Schedule of Events
|
Day |
Time |
Event |
Location |
Notes |
|
Friday, May 6th |
7:00pm |
Registration Registration
Mixer |
Lowenberger Lowenberger
Lounge |
|
|
Saturday, May
7th |
6:30-10:00 |
Plenary:
B. Rosemary
Grant Break Session
One: Behavioural
Ecology, Evolution and
Aquatic Lunch Plenary:
Lynda Corkum Break Session
Two: Behavioural
Ecology, Evolution and Conservation
Biology Poster
set-up Poster
Session Banquet |
Thistle 325 Thistle 245, 244
and 246 Thistle 325 Thistle 245, 244
and 246 Pond Inlet Pond Inlet |
-Sat.
registration takes place in Thistle |
|
Sunday, May 8th |
|
Plenary: Ellie Prepas Break Session
Three: Behavioural
Ecology, Evolution and
Neuroscience/Other Lunch Plenary: Marie-Josée
Fortin Closing
Remarks General
Meeting |
Thistle 325 Thistle 245, 244
and 246 Thistle 325 |
|
Schedule of Oral Presentations
|
Time |
Behavioural Ecology |
Evolution |
Aquatic, Conservation, and more… |
|
Saturday AM |
Thistle 245 M. Kasumovic M. Boisvert S. Vijayan J. Gorrell M. Moscicki Moderator: C. Russell |
Thistle 246 M. Johnson S.
Stewart-Williams M. Mallett M. Peso Moderator: M.
Peso |
Thistle 244 Aquatic Behav. Ecology A. Drake C. Kerling D. Linley A. Valois J. Richardson Moderator: J.
Richardson |
|
Saturday PM |
Thistle 245 Y. Brandt M. Andrade J.L. Fitzpatrick G. Burness A.
Schulte-Hostedde Moderator: A.
Sharp |
Thistle 246 D. Punzalan A. Pischedda J. Lindell G. Dingle Julie Marantette Moderator: S.
Prager |
Thistle 244 Conservation Biology V. St. Amour K. Duncan H. Kharouba J. Norghauer K. Marshall Moderator: R.
Kroeker |
|
Sunday AM |
Thistle 245 M.D. Biaggio K. Stiver M. Sudan K. Judge S. Matchett Moderator: K.
Judge |
Thistle 246 T. Kiyonari F. Chain J. Gibbs M.J. Fitzpatrick Moderator: M.J.
Fitzpatrick |
Thistle 244 Neuroscience/Other N. Lee A. Mason M. Pereira V. Redwing H. May Moderator: H. May |
Plenary Speakers
Dr. Barbara Rosemary Grant-Princeton
University
Dr. Grant is interested in the diversity of individuals produced by the
interaction between genetics, ecology and behavior. How natural selection acts on
this variation; the evolutionary response to natural selection and the bearing
this has on the process of speciation.
A fundamental problem in the study of evolution is to understand the steps
involved in the process of speciation, because the question of how one species
splits into two addresses the foundation of the biodiversity we see around us
today. Yet there is much controversy about the process of speciation. Debates
center around, the extent of the role of genetic variation, past history and geography
in lineage divergence and the role of genetic variation, behavior and learning
as factors in the formation of reproductive barriers to gene flow between
closely related sympatric species, and whether or not speciation can occur in
sympatry.
Dr. Lynda Corkum–University of
Potential
Control of an Invasive Fish, the Round Goby, using Pheromones
The success of the
invasive fish, the round goby (Neogobius
melanostomus) may be due to its pheromonal communication between males and
females during reproduction. We hypothesize that reproductive males (RM)
release pheromones into the water that attract females to nests and deter
males. Histological and biochemical studies showed that specialized glandular
tissue in the male reproductive system produce androgen steroids, two of which
(11-oxo-etiocholanolone (ETIO) and 11-oxo-ETIO-sulfate) are novel compounds in
teleosts. Lab experiments showed that males do not respond (positively or
negatively) to conspecific male odours (washings). In contrast, ripe females
exposed to RM washings spent more time near the odour source, swam faster, and
swam directly to the odour source when compared with responses to control
water. When responses of females were tested against blends of synthesized
steroids found in male round goby gonads, there was an overall significant
difference between treatment and control, but no difference in response between
reproductive and non-reproductive females. Different blends of steroids did not
elicit differences in behavioural responses by females. Although females are
attracted to the total blend of steroids, responses by females to male washings
are more dramatic. Thus, the blend of identified steroids is likely missing an
active ingredient.
Dr. Ellie Prepas-Lakehead University
Dr.
Dr. Prepas focuses on the collection and organization of an appropriate
database on fresh water in the Boreal (northern)
The modelling approach to be used in the research will be integrated into
detailed forest management plans of forest companies over the next five years.
Dr. Marie-Josee Fortin-University of
Management decisions regarding conservation reserve design are dependent on
our ability to characterize landscape spatial heterogeneity and its effects
on species biodiversity and persistence. Understanding speciesspatial
habitat requirements in fragmented forested landscapes can increase our
ability to maintain species biodiversity at the landscape scale. Here, I
present a method of using spatial graph theory to identify a network of
patches that maximizes habitat connectivity in multi-use forested
landscapes with a fixed conservation area budget. A case study in a forest
management unit in Québec is presented to illustrate the utility of
combining spatial graph measures with geomatic approaches to prioritize
patches for inclusion in a spatial reserve network.
Oral Presentation Abstracts
(Alphabetical by Presenter’s last name)
Adaptationist
lessons from the edge: sacrificial redback spiders dismantle spandrels
Maydianne CB Andrade*
Gould
and Lewontin’s influential paper (1979) emphasizes errors in the adaptationist
program. Loose interpretation of this paper has lead to frequent invocations of
constraints in explanations of behavioural evolution. I use empirical research
on self- sacrificial male redback spiders (Latrodectus
hasselti) to question whether this is the most productive approach to
understanding behaviour. I consider two contexts in which redback males are
faced with situations that strongly favour solutions that might be considered
impossible to a constraint-focused researcher. Male redback spiders facilitate sexual cannibalism by
females during mating by moving the
posterior portion of their abdomen over
the female’s mouthparts. The female begins to eat the male during
sperm transfer. However, a complete mating requires two
copulations—one with each of the female’s paired,
independent sperm storage organs, and males must achieve that second copulation despite the significant injury inflicted during the
first copulation. I show that males have
a unique trait that allows them to survive partial cannibalism by their
voracious mates and thus achieve complete copulations. Second, I show males are
able to detect and preferentially inseminate
previously- unused female reproductive tracts despite the absence of any known sense organs or cues
with which such discrimination might be
accomplished. I conclude by supporting
Alcock's (1998) argument that the
constraint-based approach to studying
behaviour may severely restrict the range of hypotheses considered plausible, and thus
may unnecessarily retard development of
understanding. (Behavioral
Ecology)
Experienced
females leave their options open: evidence for cryptic choice in redbacks
M. Daniela Biaggio* & Maydianne C. B. Andrade
Factors controlling female mating decisions are poorly understood,
but recent work suggests information gathered by juveniles might affect adult
mating behaviors. Female Australian redback spiders (Latrodectus hasselti) encounter 0-8 males in nature, yet sometimes
remain unmated. Choosiness should be affected by this risk. Adult males often
cohabit in webs with sub-adult females, so females may use male presence to
gauge the future availability of mates. We predicted females that cohabit with
males as sub-adults would be choosier than those who cohabit with younger
juvenile females or who were reared in isolation (controls). We measured adult
choosiness as the number of copulations obtained by a separate set of males in
staged matings following cohabitation. Females have paired reproductive tracts,
in each of which the first male to mate deposits a sperm plug and achieves
sperm precedence. Thus males achieve 100% paternity only if they copulate
twice. In our study, as predicted, females that had cohabitated with males
manipulated paternity by frequently restricting males to 1 or 0 copulations,
while females in both control treatments usually permitted 2 copulations
(cryptic choice). Females controlled mating through aggression or fatal
cannibalism of males after a single copulation.
Thus females may use sub-adult experience to increase the possibility of
polyandry (by preventing sperm precedence) when males are common. In contrast,
females are less choosy and reduce the risk of remaining unmated when males are
rare. This study indicates that laboratory research on mating behavior should
consider potential mating bias introduced by isolating females, particularly in
species where juvenile social interactions are common. (Behavioral Ecology)
Bumble bees (Bombus impatients) can estimate multiple
durations in concurrent fashion
Michael J. Boisvert* and David F. Sherry
All environmental events can be defined temporally by their location
in time, their position in a sequence, and their duration. It is therefore expected that temporal
sensitivity and the ability to adjust behavior to the temporal structure of the
environment should be phylogenetically widespread. Little is known, however, about
invertebrates' ability to time durations.
Bumble bees responded to the time elapsed between successive food
rewards with proboscis extension responses that were reinforced after either a
fixed interval of time or on a schedule in which time intervals of different
durations were mixed. Behavior varied
as a function of time under both simple and mixed timing conditions. In simple interval conditions, maximal proboscis
extension rates occurred near the end of the interval while in mixed interval
conditions, maximal rates were clustered around short and long interval
values. Bumble bees learned rapidly to
time interval durations and flexibly timed multiple durations simultaneously. (Behavioral Ecology)
Jaws of life:
allometry and function of spider chelicerae
Yoni Brandt* & Maydianne Andrade
The chelicerae (jaws) of spiders in the genus Tetragnatha serve an unusual function and are conspicuously
elongated, often exceeding the carapace in length. In addition to the ubiquitous
functions of subduing prey and fighting with rivals, the chelicerae are
employed for clasping and securing the partner in copulation. The degree of jaw
elongation within Tetragnatha varies
considerably between age classes, size classes, sexes and species. In many
animal taxa, copulatory appendages show negative allometry (relative appendage
size decreases as body size increases) whereas appendages used in fighting and
display are positively allometric (relative appendage size increases with body size). Herein we describe patterns of variation in
adults, as a step toward elucidating the selective pressures and constraints
that shape the length of chelicerae in Tetragnatha.
Jaw elongation is absent in juvenile instars, detectable in the penultimate instar,
and highly developed in the adults. Females are moderately larger than males in
body length, yet in all species, the chelicerae of males are longer than female
chelicerae. Among species, male jaws are moderately positively allometric,
whereas female jaws are highly positively allometric. Hawaiian species are smaller than North
American species, and the allometric coefficients in both sexes are lower in
the Hawaiian species than in the North-American species. Male and female body
length and jaw length are significantly correlated. In T. guatemalensis, a North American species, male and female
allometric coefficients are similar in magnitude to inter-specific allometric
coefficients. We discuss the potential of size- assortative mating and patterns
of intra-specific body size variation to account for patterns of Tetragnathid
jaw elongation. (Behavioral Ecology)
Energetics and
individual quality in tree swallows
Gary Burness*
Within any population, some individuals consistently achieve
higher reproductive success than others of similar age and breeding
experience. Using tree swallows as a
model, I have tried to understand some of the factors that help to define
individual “quality”. In tree swallows,
adults rearing naturally large broods of nestlings are presumed to be of higher
quality than individuals with smaller broods.
I have shown that adults rearing large broods spend less energy per
nestling than adults rearing small broods.
Despite this, the growth rate of individual nestlings does not vary with
brood size. I hypothesize that adults
rearing large broods have higher foraging efficiency, possibly due to
differences in foraging strategy or skill levels. Among swallows rearing broods of the same
size, females (but not males) with higher daily energy expenditure have faster
growing nestlings, a presumed correlate of fitness. The ability to attain high
energy expenditure seems dependent on a high digestive capacity, which may
entail elevated costs of self- maintenance.
To explore the potential trade-off between adult self-maintenance and
offspring quality, I have immunochallenged adults and nestlings at two breeding
sites differing in food availability.
Adults at the low food site did not have a depressed cell-mediated
immune response or elevated basal levels of corticosterone. Nestlings at the low food site grew more
slowly however, suggesting adults were unwilling to sacrifice their own
self-maintenance for the benefit of increased offspring quality. (Behavioral Ecology)
Multiple
Mechanisms Promote the Retained Expression of Duplicate Genes
Frederic Chain* and B. Evans
Gene duplications can facilitate genetic innovation and catalyze
reproductive incompatibilities and adaptive radiation. The mechanisms that maintain the expression
of both gene copies can exhibit coding region changes that might add,
compromise, or not affect protein function.
We tested the applicability of three types of mechanisms for promoting
the retained expression of duplicated genes in 290 expressed paralogs of the
tetraploid clawed frog, Xenopus laevis. Tests were based on explicit expectations
concerning the ka/ks ratio, and the number and location of substitutions after
duplication. Results provide evidence
for multiple mechanisms acting within the same genome, within the same
functional classes of genes, within the same period of time following
duplication, and even on the same set of duplicated genes. Each copy of a duplicate gene may be subject
to distinct evolutionary constraints, and this could be associated with
degradation or enhancement of function.
The evolution of most X.laevis paralogs
is consistent with retained expression via mechanisms that do not radically
alter functional constraints, such as selection to preserve post-duplication
stoichiometry or temporal, quantitative, or spatial subfunctionalization. (Evolution)
The
reproductive success of war heroes
Greg Dingle*
Non-kin based altruism is difficult for evolutionists to explain.
Yet people across the world are known to perform acts of extreme altruism that
appear to clash with their fitness interests. Individuals who perform these
acts are typically praised by their communities. Their actions are deemed "heroic".
This public reaction suggests possible benefits to these individuals, such as
increased attention prestige and attractiveness. If heroic acts conferred
increased reproductive success among our ancestors, then heritable traits that
underlie heroism could have been selected for. Alternatively, heroic acts may
garner only momentary gratefulness and fleeting praise. To test whether heroism
can affect reproductive success, I investigated 57 male US Medal of Honor
recipients from WWI. I found that the Medal of Honor recipients were more
likely to have married and had more children than other comparable groups of
veterans, independent of age, socioeconomic status and geographic factors.
Environmental factors affecting growth of Eastern
sand darter, Ammocrpyta pellucida, in the lower Thames River, Ontario
A. Drake*, M. Power, M. Koops, S.
Doka, and N. Mandrak
Environmental
factors affecting growth of Eastern sand darter, Ammocrpyta pellucida, in the lower
How increasing
the number of protected areas impacts species at risk
K. Duncan*, H. Kharouba and J.T. Kerr
Rates
of species endangerment in
Rapid
increases in reproductive investment in in a cooperatively breeding fish
J.L. Fitzpatrick*, J. K. Desjardins, K. A. Stiver, R. Montgomerie, S.
Balshine
One
of the outstanding puzzles in cooperative breeding lies in understanding how
reproduction is partitioned among group members. While dominant individuals may attempt to suppress
the reproduction of subordinates to maintain reproductive primacy, subordinates
may attempt to steal reproductive opportunities, potentially leading to intense
and pervasive sperm competition between dominant and subordinate individuals. If behavioural subordinates are suppressed,
then subordinate investment in reproduction should be less than dominant
individuals, but if sperm competition occurs widely then behaviourally
subordinate individuals are expected to invest substantially more in reproduction.
To examine these predictions we compared reproductive investment in dominant
male breeders and subordinate male helpers of the cooperatively breeding
cichlid Neolamprologus pulcher from
Maintenance of
polymorphic foraging strategies by frequency-dependent selection
M.J. Fitzpatrick*, E. Feder, L. Rowe and M.B. Sokolowski
Negative
frequency-dependent selection is believed to be a powerful and prevalent
evolutionary force that maintains polymorphisms in nature. If the relative
fitness of each of a pair of alleles increases when it is rare in the population,
then each allele can only achieve its highest fitness when the other is present
in the population at high frequencies. We explored whether the rover/sitter
behavioural polymorphism found in larvae of the fruit fly D. melanogaster can be maintained by negative frequency-dependent
selection. This has become a model system for behaviour genetics since it
directly links allelic variation within a gene to variation in behaviour and
orthologs have been recently found to influence similar behaviours in additional
organisms. In fruit fly larvae, rovers and sitters arise mainly from allelic
variation in the foraging gene. Rovers feed less but move more than sitters
when foraging on a food patch. Rovers are also more likely to explore new food
patches than sitters. We find that when raised under a constant density and in
conditions known to impose a stress on survival, rovers attain their highest
relative fitness when rare in the population (outnumbered 3 to 1 by sitters).
Likewise, sitters attain their highest fitness when they are similarly rare in
the population. Moreover, the involvement of the foraging gene was further
confirmed using a mutant (a sitter generated on a rover genetic background) in
place of the natural sitter strain. These results imply that rovers and sitters
can be stably maintained in nature by negative frequency-dependent selection.
Our study is important since we provide a rare example of negative
frequency-dependent selection maintaining naturally occurring allelic variation
at a single locus.
An integrative
taxonomic approach to the problematic bee subgenus Dialictus
Jason Gibbs*
Bees play a vital role as pollinators of both
wildflowers and agricultural crops worldwide.
But pollination services worldwide are in decline. Evidence also
suggests that bees may be excellent predictors of ecosystem health, because
they are more extinction prone than almost all other organisms. Despite their
importance, our knowledge of bee species richness is poor. Identification and
classification of species is integral for the understanding of biology and so
an efficient taxonomy is a prerequisite for the development of sustainable use
of natural and anthropogenically altered systems. (Other)
Are
individuals in good condition “healthy”?
A test using American red squirrels.
J. Gorrell* and A. Schulte-Hostedde
Laurentian
University
Body condition, determined
by the residuals from a regression of body mass on structural size, is presumed
to reflect individual energy reserves. A
major assumption is that individuals in good condition are better able to
withstand ecological stressors (e.g. disease) and are thus healthier than
individuals in poor condition. Aspects
of health, including hormone levels and the immune function may play a major
role with respect to individual quality.
The idea that animals in good condition are healthy has never been
tested. A wild population of American
red squirrel (Tamiasciurus hudsonicus)
from
GxE causes
variable selection on life-history strategy in Common Evening Primrose
Marc Johnson*
Monocarpic plants, where reproduction is fatal,
frequently exhibit variation in the length of their pre-reproductive period
prior to flowering. If this life-history
variation in flowering strategy has a genetic basis, genotype- by-environment
interactions (GxE) may maintain phenotypic diversity in flowering
strategy. The native monocarpic plant
Common Evening Primrose (Oenothera
biennis L., Onagraceae) exhibits variation for annual versus biennial
flowering strategies. I tested whether
there was genetic variation for flowering strategy in O. biennis, and whether environmental variation causes GxE that
imposes variable selection on flowering strategy. In a field experiment, I randomized >900
plants from 14 clonal families (genotypes) into five distinct habitats that
represented a natural productivity gradient.
GxE strongly affected the lifetime fruit production of O.
biennis, with the rank-order in relative fitness of genotypes
changing substantially between habitats.
I detected genetic variation in annual versus biennial strategies in
most habitats, as well as a GxE effect on flowering strategy. This variation in
flowering strategy was correlated with genetic variation in relative fitness,
and phenotypic and genotypic selection analyses revealed that environmental
variation resulted in variable directional selection on annual versus biennial
strategies. Specifically, a biennial
strategy was favoured in moderately productive environments, while an annual
strategy was favoured in low productivity environments. These results highlight the importance of
variable selection for the maintenance of genetic variation in the life-history
strategy of a monocarpic plant. (Evolution)
Condition-dependence
of male lifetime reproductive effort in a field cricket.
Kevin Judge* and Janice Ting
Male development
tracks rapidly shifting sexual versus natural selection pressures
M. M. Kasumovic* and M. C. B. Andrade
It is a central tenant of
evolutionary biology that natural and sexual selection often work in opposition
to shape phenotypic distributions. Australian redback spiders (Latrodectus hasselti) show large
variation in male quantitative traits. We show redback males have tactical,
condition-dependant developmental shifts tracking fluctuations in the relative
importance of competition and mate searching survival. Juvenile males exposed
to pheromonal cues of different conspecific densities rapidly shifted
development time and adult size to match the selective context likely to be
faced upon maturity. We demonstrate shifted phenotypes are optimum for the
conditions in which they arise. Males matured smaller and more rapidly at high
females densities. In these conditions, mate searching mortality is minimal,
but first male sperm precedence imposes strong selection for finding virgin
females. As predicted, small males outcompeted larger males in scramble
competitions. At low female densities, males matured larger and outcompeted
smaller males in the direct competitions more likely under these conditions.
Larger males are also more likely to survive arduous mate searching. Thus
continuous variation in male traits critical to competitive success arose from
adaptive, context-dependent plasticity. This contradicts the common emphasis on
heritable variation in the ability to acquire sufficient resources to reach
some optimum trait value (e.g., large size). Moreover, this highlights the
importance of context-specific tests of fitness. We propose that male
phenotypes alone are not good indicators of fitness, and quality should instead
be measured as the ability to develop tactically in response to cues of
environmental and selective heterogeneity. (Behavioural Ecology)
Efficacy of
anti-predator behaviour in wood frog tadpoles (Rana sylvatica)
Candice L. Kerling* and Jean M.L. Richardson
Tadpoles are vulnerable to predation, but they can
reduce risk by lowering their activity.
To test the efficacy of reduced activity level in wood frog tadpoles (Rana sylvatica), tadpoles from three
populations were subject to three predator treatments (uncaged predator, caged
predator, and no predator) for two natural predators (Notonectidae and Anax junius). The number of tadpoles active was surveyed
both at the start and end of a 24 hour test period, and mortality examined in
the uncaged predator treatment.
Proportion of tadpoles active decreased as predation risk
increased. Predator type did not affect
tadpole behavioural response or mortality rates. Predation rates did differ among the three
populations studied. These results
combined suggest tadpoles respond to predation risk in a complex and
population-specific manner. Future work
will look for non-additive effects of multiple predators and examine neighbour
effects on survivorship. (Behavioral Ecology)
The
effectiveness of protected areas in
H.M. Kharouba* and J.T.Kerr
There is increasing evidence that global changes
(i.e. climate and land use) have affected the distribution of several taxa.
This redistribution is expected to alter the species assemblages of parks as
ranges shift relative to these areas. Here, we studied the impacts of recent
global changes on the distribution of Canadian butterfly species within
protected areas. We measured change in species richness and turnover for 187 butterfly species in
long- established protected areas networks across two epochs (1880-1949 and 1950-2000) using
recently established distribution
modelling techniques. To determine the
effectiveness of these reserve networks, we compared richness change in the
networks within each ecozone to randomly selected areas using a null model.
Butterfly species richness has generally increased throughout
Punishing
doesn’t yield a solution to the problem of cooperation but rewarding does
Toko Kiyonari*, Pat Barclay, Margo Wilson, & Martin Daly
Cooperation within non-kin groups presents an
evolutionary puzzle. Punishment can sustain cooperation, but the provision of
such “altruistic punishment” suffers from a second-order free-riding problem
since non- punishers can free-ride on the costly punishment provided by others.
A possible solution to this problem is “second-order punishment” of non-
punishers; more generally, the threat or promise of higher-order sanctions
might be what maintains the lower-order sanctions that enforce cooperation in
collective action problems. In a previous study, we found that voluntary
second- order punishment was very rare, but second-order rewarding was common
enough to cover the costs of first-order rewarding. The present study extended
these findings by showing that people typically didn’t reward those who
“altruistically” punished non-cooperators, but did punish those who failed to
reward cooperators. This suggests that people are more inclined to reward those
who deliver altruistic benefits than those who deliver altruistic punishment,
and thus that rewards may have played a more important role than punishment in
the emergence of human non-kin cooperation. (Evolution)
How a fly
knows what’s what and where it is
N. Lee* and A. C. Mason
Ormia
ochracea are acoustic parasitoids of singing crickets that
possess a specialised auditory system capable of accurate sound source
localisation. Directional hearing functions solely in the context of localising
the 5 KHz tone pulses of host cricket calling songs. Correct phonotaxis
involves both recognition and accurate localisation of a sound source, and both
of these tasks require precise measurements of time intervals between sound
pulses originating from the same source. However, the natural auditory scene is
often complex as multiple signalers may produce sound pulses that overlap in
time, therefore masking temporal cues used in these auditory processing
tasks. Indeed, behavioural experiments
have previously shown that flies misdirect their phonotaxis behaviour under
certain stimulus conditions. We use stimulus conditions with known behavioural
responses and simultaneous summed nerve recordings from the left and right
auditory tract to describe neural response parameters that correspond with
correct and incorrect phonotaxis behaviour. Results indicate that summed nerve
response amplitudes are dependent on the duration of the time interval between
arriving sound pulses. Responses from
the left and right auditory tract are equal in amplitude to the first set of
competing pulses for all stimulus conditions. Response amplitude to subsequent
pulses decrease when competing sources overlap in time, with most prominent
amplitude decreases observed in response to a contralateral sound source. This study is the first step to describing
auditory processing of multiple sound sources in Ormia and neural response
parameters are found to be consistent and can predict correct and incorrect
phonotactic responses. (Behavioral Ecology)
Sharp mtDNA
contact zones contradict ongoing gene flow in Baja Californian lizards
Johan Lindell*, Fausto R. Méndez-de la Cruz and Robert W. Murphy
Department
of Zoology,
Contact zones have been described as “natural laboratories
for evolutionary studies” where evolutionary processes such as natural
selection, development of isolation mechanisms, and speciation can be studied.
Contact zones have historically been viewed as evolutionary intermediate stages
of relative short time span, terminated either by resumed gene flow leading to
reunion of differentiated populations or by the development of isolating
mechanisms leading to speciation. We present an old and remarkably sharp
contact zone in mitochondrial DNA in the black-tailed brush lizard (Urosaurus nigricaudus) of
The
maintenance of genetic variation for fitness in an unchanging environment
Martin A. Mallet* and Adam K. Chippindale
Queen's
University
The occurence of substantial genetic variation for
fitness, even in laboratory populations maintained under constant conditions,
presents a question that is central to evolutionary genetics. The forces
maintaining this variation in large outbred sexual populations have received
little direct empirical study, despite much theoretical work. Part of the
problem is that net fitness is a slippery measure; its components may be
negatively correlated and it is sensitive to the genetic and environmental
context in which it is measured. We can use laboratory-adapted populations to
overcome these difficulties because their well- defined lifecycles make total
fitness directly measurable. Using a population of D. melanogaster isolated in 1975 and maintained at large population
sizes under relatively constant conditions, we propose to quantify the factors
which contribute to the maintenance of genetic variation for total fitness in
an unchanging environment. Genetic variation for net fitness will be measured
using hemiclone analysis, which allows us to isolate haploid genomes from the
base population and measure their average fitness effects. Fitness of these
haploid genomes will be assessed both when expressed as males and as females,
giving us an estimate of their sex-dependent fitness effects. Using this
system, we will also assess the impact of mutation on the entire genome without
the artefacts associated with inbreeding as well as examine the contribution of
interactions between whole genomes in determining individual fitness. Together,
these experiments will yield insights into the genetic structure of fitness in D. melanogaster, and the forces which
create and maintain genetic variation in the ultimate currency of selection. (Evolution)
Seismic signal
production in a wolf spider: parallel vs multicomponent signals
Elias, DO, Lee, N, Hebets, EA, Mason, AC*
Animal signals can consist of multiple parts within
or across sensory modalities (multi- component signals or multimodal signals).
While recent work has focused on multimodal signals, the production, processing
and evolution of multi- component signals has received considerably less
attention. Here, using synchronous highspeed video and laser vibrometer
recordings followed by experimental manipulations of putative sound- producing
structures, we explored the mechanisms of seismic signal production in the
courtship display of Schizocosa
stridulans Stratton. Two types of seismic courtship signals were observed. Revs consist of a high- frequency component
produced by flexions of the male pedipalp (stridulation) simultaneous with a
lowfrequency component produced by movements of
the abdomen (tremulation). This multi-component signal is produced by
independent structures and represents a parallel multi-component display. By
contrast, idle displays consist of a high- intensity component produced by
drumming of the forelegs on the substrate (percussion) followed by a
high-frequency component produced by flexions of the male pedipalp
(stridulation). While the components of the idle display are also produced by
independent structures, the leg drumming and palp flexions occur serially and
do not overlap in time. We discuss the
selective pressures that may drive the evolution of multiple sound-producing
structures as well as the selective pressures that drive the evolution of
parallel versus serial multi-component signals. (Ethology/Neuroscience)
Does scent
reinforcement affect spatial learning in a nocturnal gecko?
S. Pasachnik,
In
their natural environment, animals must navigate around their home range in
order to find the optimum shelter, food source and mate selection. In animals with
a known affinity for a discrete home range, individuals use a variety of
indicators to identify the most advantageous choice available. Discerning how
reptiles negotiate their way through life has been extensively studied but
rarely in the context of chemosensory cues. Also, maze-learning and orientation studies have been confined
to typically only the specific task at
hand and not relative to condition of
the reward (be it food, heat, shelter, mate, etc.). Velvet geckos (Oedura lesueurii) are highly selective
in habitat choice and suitable retreat-sites are chosen based primarily on
thermal preferences, social interactions and predator avoidance. Previous
experiments have shown avoidance of predators to be of higher priority than
thermoregulation, yet in other trials, social interaction (presence of a larger
male) took precedence over predator avoidance. Based results of an extensive,
long- term field study, laboratory experiments were carried out to gauge the
extent to which chemosensory navigation and memory are involved in retreat-site
selection. We tested the hypothesis that location and condition of a favourable
retreat-site can be learned, and whether a non-threatening scent cue reinforces
that learning. The results of the learning trials and implications for further
field studies will be discussed. (Behavioral Ecology)
Responses of
Crayfish to a Reflective Environment Depend on Dominance Status
H.Y. May* and A.J. Mercier
Previous research has shown that several aspects of
behaviour exhibited by socialized crayfish are modified by mirrors or by the
reflection in a glass aquarium.
Socialization of crayfish is known to generate a dominance hierarchy
composed of dominant and subordinate animals.
The present study tested the hypothesis that responses to a reflective
environment depend on dominance status.
50 crayfish were maintained in pairs for two weeks to establish stable
dominance ranks. 25 crayfish were
isolated for two weeks and used as a control group. All crayfish were observed in an aquarium in
which half of the walls were lined with mirrors and the other half were lined
with non-reflective plastic. Dominant
crayfish spent significantly more time on the reflective side of the aquarium
than on the non-reflective side, while subordinant and isolated crayfish showed
no preference. Dominant crayfish spent
more time in reflective corners, turned more frequently toward reflective
corners and crossed more frequently toward reflective walls. Such differences were not observed for
subordinate or isolated crayfish.
Subordinate crayfish exhibited more reverse walking on the reflective
side of the aquarium than on the non-reflective side, but other groups did not. Thus, responses to a reflection depend on
dominance status. Future research will
use heart rate recordings to examine the physiological state of crayfish while
exploring a reflective environment. Research supported by NSERC. (Ethology/Neuroscience)
Performance
and herbivory of tropical tree seedlings after experimental defoliation: effec
Julian M. Norghauer*, Jay R. Malcolm, Barbara L. Zimmerman
Faculty
of Forestry,
Despite the posited importance of insect herbivory
in affecting tropical tree populations and the vulnerability of seedlings,
herbivory of juvenile plants and interactions with biotic and abiotic factors
have rarely been examined in concert. Here, we tested predictions of several
key hypotheses, including the Limiting Resource Model (LRM), the Plant Vigour
Hypothesis (PVH), and the Janzen-Connell Mechanism (JCM). We outplanted
mahogany (Swietenia macrophylla King)
juveniles into canopy gaps and understorey and
compared their performance under simulated attack by a specialist caterpillar (Steniscadia
poliophaea) by clipping 0%, 10%, 50%, or 90% of leaf area. Seedling performance and natural
herbivory were measured over the subsequent 8 mo. Predictions from the
hypotheses were supported in all cases.
As predicted by the LRM, juveniles in gaps tolerated simulated herbivory
very well (3% died), whereas 79% of severely damaged (90% clipped) understorey
juveniles died. However, moderate to severe simulated herbivory (50% and 90%)
reduced gap juveniles’ above-ground growth by 36% and 56% respectively and
resulted in smaller-sized leaves being produced (irrespective of canopy cover).
As predicted by the PVH, gap juveniles consistently produced more and larger
leaves than understorey juveniles, but also suffered greater percent post-clipping herbivory (up
to 100% leaf area lost) than in the
understorey. All gaps were discovered by
the specialist folivore, whereas it caused damage at only ~30% of understorey
locations. Support for JCM was limited to the wet months and was influenced by
canopy cover. Early-wet season herbivory to gap juveniles increased with total
conspecific adult numbers and dbh within a 125-m radius, bu not in the mid-wet
months; whereas more understorey juveniles were attacked near (<50 m)
reproductive adults in both early- and mid-wet months. Collectively, our results
suggest that S. poliophaea can
function as both a distant- and density-responsive enemy; and hence is capable
of generating strong Janzen-Connell effects on juvenile growth and limiting
recruitment of S. macrophylla in this
forest. We conclude that a richer, more comprehensive picture of Janzen-Connell
type plant-insect dynamics can emerge by integrating light availability in
tropical forests and its consequences for host-plant tolerance, vigour, and
susceptibility to natural enemy attacks. (Conservation Biology)
Usefulness and
the Picturesque: An Experiment in Ecocriticism
Michael Pereira*
Deep ecologists Bill Devall and George Sessions once
remarked that the environmental crisis resultant of technocratic-industrial
societies is increasingly “coming to be understood as a crisis of character and
of culture”. This paper is an experiment in a kind of cultural criticism which
centres on just such a point of view.
Through a brief overview of ecocritical methodology followed by a
detailed case study this paper explores the potential for an ecologically
informed criticism to begin unearthing the historical and cultural roots of the
contemporary environmental crisis. The paper begins with an examination of what
“ecocriticism” is and a brief profile the field’s evolution. Following this is
a detailed case study comparing
Christopher Columbus' "Journal from
the First Voyage to America" to
Ralph Waldo Emerson's essay
"Nature", which endeavours the demonstrate how the ecocritical method
can be applied textually, and the
possibilities it opens for deeper
reconsideration of cultural history. In conclusion, I suggest that while science
and technology have served as manifestations of a deep cultural pathos, it is
ultimately our culture, indeed our very attitudes and perceptions of nature
that must evolve if we are to survive. (Other)
Influence of
body size on egg size in solitary and eusocial bees
Marianne Peso* and Miriam Richards
Fully
developed bee oocytes (eggs) are sausage-shaped, slightly curved and variable
in size. Egg size varies across bee
species in accordance with the level of sociality (Michener 1974), solitary
bees laying the largest eggs and highly eusocial bees laying the smallest eggs
relative to their body sizes. I examined bees from different taxa exhibiting
different levels of sociality. Since most solitary bees produce only one brood
per season, they may be able to invest more resources into each egg than eusocial
bees that have several broods per season.
I recorded a number of body size measurements, including head width,
subcostal vein length, intertegular width, abdomen width, and femur length as
well as egg length and egg width measurements. Egg volume was approximated by
using egg width and length measurements to calculate the volume of a cylinder.
Preliminary results from Augochlorella
striata, Halictus ligatus and Osmia conjuncta, Ceratina calcarata and
Xylocopa virginica indicate that egg size varies with body size. According to both the principal components and
the regression analyses, head width positively correlates with egg length,
indicating that the larger the bee, the larger the egg. The regression analysis
also shows a positive correlation between species and egg length. This suggests
that the egg size and body size relationship remains consistent across bee
species and does not vary with sociality. It is possible that full egg size is
limited by body size in females who still need to fly while developing large
eggs. More bee species representing other levels of sociality will be included
in this analysis to see of the relationship still holds true. (Behavioral Ecology)
Hope for the
shallow end of the gene pool: Sexual conflict opposes sexual selection
Alison Pischedda* and A. Chippindale
Queen's
University
Evolution based on the benefits of acquiring ‘good
genes’ in sexual selection is only
plausible with the reliable transmission
of genetic quality across generations. Accumulating evidence suggests
that sexually antagonistic (SA) genes with opposite effects on fitness when
expressed in the two sexes may be common in animals and plants. These SA genes
should weaken the potential indirect genetic benefits of sexual selection by
reducing the fitness of opposite-sex progeny from high fitness parents. Here we
use hemiclonal analysis in Drosophila
melanogaster to directly measure the inheritance of fitness. We show that
any potential genetic benefits of sexual selection are reversed because high
fitness males produce low fitness daughters, and high fitness females produce
low fitness sons. Moreover, male fitness
was not inherited by sons, consistent with theory and evidence connecting SA genes
with the X chromosome. This inheritance pattern may help explain how genetic
variation for fitness persists in spite of strong sexual selection, and why the
ZW sex-chromosome system in birds and butterflies fosters the evolution of
extreme sexual display traits in males. (Evolution)
Condition
dependence of sexually dimorphic colouration and longevity in the ambush bug
David Punzalan*, M. Cooray, F. H. Rodd and L. Rowe
Sexually selected traits are predicted to exhibit
stronger condition dependence than non- sexually selected traits. We tested this prediction in the colour
dimorphic ambush bug Phymata
(Evolution)
Swimming
Endurance in Tadpoles
J. Richardson*
Larval anurans (tadpoles) segregate into pond types
that differ in predator regime and permanence.
Different pond types favour different, incompatible, trait values in
tadpoles inhabiting those ponds and this has resulted in a diversification of
larval traits in anurans using different pond types for breeding. Burst swimming speed in response to a simulated
predator attack is one such trait.
However, little is known about sustained swimming ability in tadpoles, a
second component of swimming performance that may be important to larval
fitness in the presence of predators. In
this study, I consider the swimming endurance of tadpoles from species of three
different anuran families (Pseudacris
triseriata, Rana sylvatica, Bufo americanus) and show that swimming
endurance differs significantly among species, and in accordance with pond use
and activity level. (Behavioral Ecology)
Geographic
variation in ejaculate investment in walleye
Albrecht Schulte-Hostedde*, Tracy Dannell, and George Morgan
Laurentian
University
Walleye (Sander
vitreus) are large, freshwater fish with a mating system under which sperm
competition is likely to occur.
Variation in the relative size of the testes is evident across
populations, ranging from 1.73% to 4.32% of somatic body mass. Here, we use data from 60 lake populations of
walleye spanning northern
The Role the
Ranavirus in Relation to Fluctuating Asymmetry in the Green Frog (Rana clamitans)
V. St-Amour* and D. Lesbarrères
Laurentian
University
Amphibian
populations are facing rapid declines and recent discoveries have shown that
Emergent Infectious Diseases (EIDs) such as Ranavirus and chytrid fungus are
playing major roles. Although these diseases are involved in the decline of
certain populations little is known about the effects of these EIDs in relation
to development. Developmental stability
can be measured using fluctuating asymmetry (FA) which is often used as a tool
to measure stress and the overall fitness of organisms. The theory assumes that an organism presents
mechanisms that control asymmetry during development. Such mechanisms may be
costly to the individual and when faced with other stressors it is believed
that these mechanisms will suffer resulting in fluctuating asymmetry. Using genetic tools several populations of
green frogs (Rana clamitans) were
analyzed for presence or absence of Ranavirus. Infected and non infected
individuals were then measured to determine FA under the hypothesis that FA
will be more likely to be observed in individuals infected by Ranavirus. Since secondary sexual traits are more costly
than non-sexual traits we also expected to observe FA in the former rather than
in the latter. Preliminary results show
a trend of fluctuating asymmetry when comparing sexual traits among infected
and non-infected individuals. This shows
that not only are EIDs causing massive die offs they are also having a further
reaching effect on the development of those individuals carrying the diseases.
(Conservation Biology)
Altruistic
behaviour among kin versus non-kin
Steve Stewart-Williams*
Evolutionary
principles suggest that, although altruism need not be directed exclusively toward
kin, there will be differences in the nature of altruism among kin vs. non-kin.
The present study sought to explore these differences. Participants were 295 undergraduate students
who each completed a questionnaire about help exchanged with siblings, cousins,
acquaintances, or friends. For siblings, cousins, and acquaintances, greater
relatedness was associated with higher levels of helping. Friends were an exception, however, receiving
as much or more help than kin. Consistent with an evolutionary analysis, as the
cost of helping increased, a higher proportion of help went to siblings and
cousins, and a lower proportion to acquaintances and friends. For low-cost
help, people helped friends more than kin. In contrast, for medium-cost help,
they helped siblings and friends equally, and for high-cost help they expressed
a greater willingness to help siblings than friends (despite being closer to
friends). Partial support was found for the hypothesis that non-kin
relationships involve higher levels of reciprocal exchange than do kin
relationships. These findings are not readily explained in non-evolutionary
terms, and therefore constitute good support for an evolutionary explanation of
human altruism. (Evolution)
Relatedness
estimates suggest male-biased dispersal in a cichlid fish
K.A. Stiver*, J.K. Desjardins, J. Fitzpatrick, B. Neff, J.S. Quinn &
S. Balshine
Ecological
constraints can lead to delayed dispersal, a hallmark of cooperative breeders.
Limited dispersal may result in genetic isolation due to decreased gene flow
between subpopulations. However, even
in such philopatric species, sex differences in costs and benefits associated
with dispersal may predispose one sex to disperse. Recent theory suggests that
a critical factor determining sex-bias in dispersal is comparative risk of kin
competition; for example, where males experience increased mating competition
relative to females, they are expected to be the dispersing sex. To test this theory, we used calculations of genetic
similarity to estimate sex-bias in dispersal using a cooperatively breeding
cichlid fish from
(Behavioral Ecology)
Male Mate
Choice in the Guppy (Poecilia reticulata)
Meeta Sudan*
Males
generally maximize their reproductive success by mating as many times as
possible. Nevertheless, when mating indiscriminately
is costly for males and females vary in quality, males are expected to be
selective. Research has shown that male
guppies (Poecilia reticulata), favour larger females over smaller females, as
female fecundity increases with body size.
In addition, non-pregnant females tend to receive more courtship
displays than pregnant females.
However, these previous studies did not account for female response to
males, as female behaviour might have affected males’ mate preferences. Pregnant female guppies are markedly
unreceptive to male courtship.
Furthermore, pregnant females develop a distinct dark spot near their
anal fins called a gravid spot. Males
may use this to avoid wasting time and energy on courting or attempting to
copulate with pregnant females. I used
the guppy to examine male mate preference for female pregnancy status and size
while strictly controlling for female response and based solely on visual
cues. I predicted that, given a choice
between females of varying size and mating status, males should choose virgin
females over pregnant females regardless of size. I found that males did not display any
significant mate preferences, which is in contrast to my previous study, which
showed a significant preference for virgin females. Whereas the previous study only physically
separated males and females for months during maturation, the present study
separated them physically and visually.
Therefore, male visual experience of females may have an important
influence on male mate selection and deserves further investigation.
(Behavioral Ecology)
The effects of
added landscape cover on foraging behaviour of gerbils
S.Vijayan*, B. P. Kotler and S.Mukherjee
Ben
Gurion Unversity, Israel, (previous)
The
effects of added landscape cover on foraging behavior of two coexisting gerbils
(Gerbillus pyramidum and Gerbillus andersoni allenbyi) were
investigated by experimentally manipulating cover patches in an otherwise
natural setting. The artificial cover manipulations were used to manipulate the
predator lethality (mainly foxes) in the grids.
Three types of cover manipulation were used in the experiment, i.e. No-
Fox cover (low cover, 10 cm), Fox cover (high cover, 30 cm) and natural cover
(control) with no addition. By providing additional artificial cover and food
patches, we quantified how foraging decisions (like time allocation,
apprehension) are affected by the risk of predation. I used manipulated seed
resource patches (seed trays) with electronic readers (“smart” seed trays) to
record the species foraging activity. The gerbils showed significantly lower
GUDs (giving up density: the amount of seeds remaining in a food patch
following a forager’s visit) in the no-fox cover patches as compared to the other
two cover types. Thus, no-fox cover provided low cost of foraging in terms of
reduced predation risks. At no-fox cover stations, the dominant species G. pyramidum had significantly lower
GUDs compared to G. andersoni allenbyi,
suggesting it to be more efficient than the latter. The cover manipulation also
had a significant effect on habitat quality as the numbers of gerbil burrows
were significantly greater at no-fox cover stations than the other station
types, suggesting a preference for habitats in which high quality refuges from
foxes are abundant. Data from the
electronic seed trays reveal that the average activity time in different cover
types were significantly different. The gerbils in no-fox cover stations showed
lesser activity, but had lower GUDs (higher harvest rates), suggesting that
they can effectively use their activity time in foraging without worrying about
their safety. In control stations (natural habitat), high activity time with
higher GUDs suggest that the gerbils apparently have to devote more time in
vigilance related activities, which is consistent with the results from
previous studies on rodents. However, in
fox cover stations the gerbils had the least activity with high GUDs suggesting
less preference of habitats in which the covers merely acts as an obstruction
instead of providing safety. Fox activity was significantly higher in control
stations compared to other cover types and was with accordance to the gerbil’s
behavior of selectivity for the full tray (measure of apprehension). (Behavioral
Ecology)
Poster Presentation
Abstracts
(Alphabetical by Presenter’s last name)
Theromoregulatory responses of the bearded dragon, Pogona vitticeps, to hyphoxia
Viviana Cadena Ruiz *
It
has been demonstrated that lizards significantly lower their preferred body
temperature in response to low oxygen concentrations as a way of protecting
vital organs from oxygen depletion. It has also been proposed that lizards will
thermoregulate less precisely when the costs associated with it are high. We
evaluated the effect of four levels of hypoxia (10%, 7%, 5% and 4%) on the
precision and level of thermoregulation of the bearded dragon, Pogona
vitticeps. The upper (UET) and lower (LET) ambient escape temperatures as well
as the selected ambient (Ta) and internal body temperatures (Tb) of eight
bearded dragons were tested in an electronic shuttle box. Tb was significantly
lowered from 34.7 °C in normoxia to 33.1°C at 4% O2. Although hypoxia had no
significant effect on UET, LET was significantly reduced from 25.7 °C at 21% O2
to 21.4°C at 4% O2. The precision of thermoregulation was determined by the
preferred Tb range (given by the central 68% of the distribution). The
preferred Tb range was found to be progressively wider with exposure to lower
O2 concentrations and significantly different between normoxia and 4% O2 (27.6
to 41.0 and 23.2 to 40.6 °C respectively). The present study indicates that,
during profound hypoxia (4% O2), the bearded dragon reduces O2 demands by both,
lowering its preferred Tb and minimizing locomotion at the expense of precise
behavioural thermoregulation. (Other)
Allometry and
sexual selection in the whirligig beetle Dineutus
nigrior
E. Fairn*, A. Schulte-Hostedde and
Y. Alarie
Laurentian
University
Sexually
selected traits often exhibit positive allometry and the presence of positive
allometry in a trait can be interpreted as evidence that larger trait size is
favored by sexual selection. The “one-size fits all” hypothesis suggests that
sexual selection favors an intermediate size in male genitalia and predicts
that the allometric slope for male genitalia is lower than for other body
parts. Mating behavior in whirligig beetles includes males attempting to grasp
and hold the female using protarsal pads covered with adhesive setae. Females
resist copulation attempts by swimming erratically. The male accessory gland
produces components of the ejaculate that in some insects induce ovulation or a
refractory period in females and therefore decrease the risk of sperm
competition. We used allometry and a mating experiment to test the “one-size
fits all” hypothesis and to determine if body size, protarsal pad size, and
accessory gland size are sexually selected in the whirligig beetle Dineutus nigrior. The allometric slope
for aedeagus length was the lowest of the traits we tested which is consistent
with the prediction from the “one- size fits all” hypothesis. The length and
width of the male accessory gland exhibited positive allometry suggesting that
this trait is sexually selected. The size of the protarsal pad was isometric
and was not correlated with any measure of mating success. Body size was
associated with the probability of obtaining a copulation and was correlated
with total reproductive effort suggesting body size may be sexually selected. (Evolution)
Maintenance of
the rover-sitter polymorphism of Drosophila
melanogaster
Elah Feder, Mark Fitzpatrick, Marla Sokolowski, Locke Rowe
One
of the central problems in evolutionary biology is the question of what
maintains non-neutral genetic variation. Yet empirically supported explanations
for genetic variation in natural systems are rare. The naturally occurring rover-sitter
polymorphism of Drosophila melanogaster
presents us with an ideal system for exploring this problem. A recent study found that larval viability of
rovers and sitters is negatively frequency- dependent when reared in
low-quality food conditions. To assess
the robustness of this phenomenon, I set up populations consisting of either
rovers or sitters and introduced first instar larvae of either rover or sitter
genotype at one of three times in population development: 24 hr (early), 48 hr
(middle), 96 hr (late). Results from 3
runs of this experiment were variable, but suggested that the operation of
negative frequency dependence is sensitive to the degree and quality of stress
experienced in the environment, with frequency dependence only being detected
when conditions were neither overly stressful nor benign. In addition, late treatments (96 hr) in all 3
runs exhibited average survivorship levels 20% or less with no detectable
frequency dependence, suggesting that environmental conditions deteriorated
rapidly and that negative frequency dependence may be important early in
population development when the major stressors are competition for food rather
than waste accumulation.
(Evolution)
A comparison
of ethanol and methanol for preserving bees (Hymenoptera: Apoidea).
M. Frampton1*, S. Prager1, S. Droege2,
and M. Richards1
1Brock
University, St. Catharines, Ontario.
2 Patuxent Wildlife Research Centre, Beltsville, Maryland.
Several methods have been reported for preserving insect specimens for the purpose of maintaining collections. We have evaluated the use of different alcohol preservatives to determine which is preferable for maximizing DNA retrieval and PCR amplification. Three bee species, Lasioglossum (Dialictus) admirandum, Lasioglossum marginatum and Augochlorella striata were stored in either ethanol (50, 70 or 95%), methanol (50 or 95%) or in an ethanol-methanol solution (70:30 or 95:5). Extracted DNA was quantified both visually and spectrophotometrically. Polymerase chain reaction was performed on the cytochrome c oxidase subunit I gene. The quality of PCR amplification was determined visually using ethidium bromide staining and was scored based on the brightness of the bands. Preliminary results suggest that maximum DNA can be extracted from samples stored in 50% methanol and that maximum PCR amplification is obtained from specimens stored in ethanolic solutions of >70%. (Other)
Sperm
longevity affects female remating rate: evidence from experimental evolution
Jessica Kundapur* & Adam Chippindale
Queen's
University
The
post-copulatory survival of sperm, which can potentially affect sperm
competition and remating rates, is highly variable across taxa. However,
surprisingly little is known about genetic variation in the characters
influencing sperm storage or longevity. In Drosophila, recent evidence suggests
that (1) sperm cells experience either mass mortality within, or ejection from,
the female reproductive tract over relatively short periods of time, (2) there
is genetic variation in both male and female aspects of sperm competition, and
(3) sperm size coevolves with the female storage organs. I attempted to
experimentally evolve enhanced sperm longevity by depriving mated females of
males for 10 days prior to founding a new generation. After over 20 generations
of selection, females in selected lines were less likely to remate when exposed
to new males and had increased numbers of offspring irrespective of the
presence of males, compared to controls. These data point to a complex set of interactions
between the sexes and reproductive strategies.
(Evolution)
Population
genetics and landscape ecology of muskrats (Ondatra
zibethicus)
Sophie Laurence* and Albrecht Schulte-Hostedde
Laurentian
University
Environmental
factors such as physical barriers have been shown to affect gene flow and
population genetic structure. Small species are expected to show more evidence
of spatial structuring than large species which have greater potential to
disperse and have large home ranges. In
terms of dispersal and gene flow, genetic distances between populations may
vary depending on habitat fragmentation and physical barriers resulting in
potential geographic isolation. The muskrat, Ondatra zibethicus, will be used as a model to examine these
issues. Because of the biology of this species, substantial genetic
differentiation at small geographic scales is predicted as is significant
isolation by distance. However, other characteristics of the species ecology
may promote relatively high rates of gene flow. Moreover, populations may show
genetic evidence for sex biased dispersal. Reduction in gene flow leading to
population genetic structuring should ultimately lead to population divergence
with respect to phenotype. These
phenotypic differences may be the result of local adaptation or genetic drift.
To examine this issue, we are examining skull morphology as a measure of
phenotypic variation to determine whether genetically structured populations
have diverged enough to result in phenotypic divergence. Comparisons among
populations in the context of habitat will allow us to determine if these
differences are the result of random drift or due to adaptations to local
habitat condition.
(Landscape Biology)
Geographic
variation in the design of male threespine stickleback nuptial signals
A.Y. Laurin* and R.J. Scott
The
threespine stickleback fish (Gasterosteus
aculeatus) is an excellent model for studying the evolution of
communication systems. Males of this
species produce a nuptial signal that is comprised of a red chin, blue-green
dorsum and bright blue iris. The signal has been studied extensively under
laboratory conditions and shown to play a role in both inter- and intra- sexual
selection as well as in pre-mating reproductive isolation. Although much is known about the strategic
design (function) of this signal, very little is known regarding its tactical
design (structure). Signalling theory
predicts that the tactical design of a signal ill be shaped by the signalling
environment to maintain effectiveness (i.e., the signal stimulates the
receiver’s sensory system). In the context of stickleback, male nuptial signals
are expected to be correlated with variability in spectral characteristics
among lakes in order to maintain signal effectiveness (contrast). Here, we report the first examination of
stickleback nuptial signals in the wild, and show that chromatic and brightness
contrast among spectrally divergent lakes is achieved by modifying signal
design. (Evolution)
Mechanisms
behind climate induced changes in Arctic aquatic ecosystems
A. Medeiros*
While
changes in chironomid and diatom community composition have been linked to
climate change, the actual mechanisms in which climate warming has affected
invertebrate populations have not been elucidated. If permafrost layers are
decreasing in thickness, there could be greater interaction of pond, lake, and
stream water with hyporheic environments and groundwater inputs. Since hyporheic zones are known to influence
nitrate and phosphorus concentrations, a larger hyporheic influence could lead
to greater abundances in algal and chironomid communities. These influences could cause the alteration
and reorganization of arctic food-webs and community structure. It is therefore
necessary to identify the influence of climate change on the active
hydrological zones in arctic ponds, lakes, and streams, to evaluate their
potential impacts on biological communities. (Aquatic Ecology)
Effects of
veiling light on nuptial signal characteristics in threespine stickleback, Gasterosteus aculeatus
Valerie Mucciarelli*
Communication
involves the generation, transmission, and reception of signals and is essential
for a variety of functions including mating.
Effective mating signals are those that are conspicuous with respect to
the communicator's background and that transmit well through the signaling
medium. Male threespine stickleback (Gasterosteus aculeatus) develop a
nuptial signal (red chin) that is an effective signal in most coastal and
freshwater habitats. Never the less, spectral properties of water vary among
different environments and consequently variation in signals may arise among
populations to maintain signal effectiveness.
I investigated the relationship between the veiling effect (light
between the observer and an object is scattered, decreasing the contrast
between an object and its background) among several British Columbia lakes and the
threespine stickleback nuptial signal variation. I found that peak reflectance of male nuptial
signals shifted to longer wavelengths in lakes that had the poorest
transmission of red light. I also developed and tested a mathematical model of
signal contrast degradation based on the human visual system. This model can be applied to the threespine
stickleback visual system to predict variability among lakes in male signal
characteristics. (Aquatic Ecology)
The effects of
weather variation and habitat alteration on Niagara Region bee population
dynamics
Sandra Regan*, Amy Rutgers-Kelley, and Miriam Richards
In 2001 the Glenridge Quarry landfill was
closed and converted into a naturalization site of Carolinian grassland and
meadow. From 2003 to 2005, bees were collected in six sites at the
naturalization site and the adjacent Brock University campus using standardized
collection methods. Bee specimens were identified, counted and measured to
examine population dynamics and response to annual weather and disturbance
changes.
In years with hot and dry weather, ideal foraging conditions, bee brood should be larger in terms of abundance or body size. In cold wet years, brood should experience reduced abundance or body size. I found a significant effect of annual variation on bee abundance but not body size.
In 2003 collection sites were established and classified by disturbance levels. Since 2003, two high disturbance landfill sites have decreased in disturbance accompanied by an increase in bee abundance. Two low disturbance old field sites have experienced an increase in surrounding disturbance leading to a decrease in bee abundance. Meanwhile, an intermediate disturbance meadow has maintained both interference level and relatively stable bee abundance through three years of collection with slight variation accounted for by annual weather conditions.
Annual abundance fluctuations show how rapidly bee populations respond to anthropogenic impacts changing their habitat through both restoration and degradation. Abundance does vary with annual weather change but patterns are noticeable only in relatively stable landscapes where the impacts of ongoing habitat alterations do not override.
Speciation in
a bottle: Does intersexual coevolution drive evolutionary divergence
Mark Rogers*, Adam Chippindale
Queen's
University
Theory
suggests that a combination of genetic drift and intersexual coevolution may be
a potent mechanism of speciation. We have been investigating the apparent rapid
divergence of reproductive traits in a unique complex of laboratory-evolved
Drosophila populations. A laboratory- adapted founder population was split into
six sister populations which have now been evolving under identical conditions
in allopatry for ?700 generations. Using genetically-marked replica populations
of all six original populations we conducted a full-generation competitive
fitness assay with all possible combinations of populations. Preliminary analysis
has revealed that female (population) fitness was highest when two different
populations were combined. This effect may derive from divergence in characters
relating to resource competition or reproductive interaction between the sexes.
If the latter, it suggests that foreign males are, on average, less harmful to
females than local males are, promoting gene flow if these populations came
back into contact at a hybrid-zone. (Evolution)
Prospective
Range Expansion Due to Global Warming in the Large Carpenter Bee, Xylocopa virginica virginica.
Dimitri A. Skandalis, Sean Prager, Glenn J. Tattersall, Joshua C. Shaw, Miriam H. Richards
Our group focuses on the life history of the large carpenter bee, Xylocopa virginica virginica, at the northern extent of its range, currently, Southern Ontario in Canada, and Maine in the United States. Unlike other overwintering insects, the large carpenter bees nest in exposed wood structures, which afford little or no protection against the winter climate. X.v. virginica is intolerant of freezing, but can maintain liquid tissues well below the equilibrium freezing point (supercooling to ~-30°C, equilibrium freezing at ~-4°C). The minimum extreme winter temperature thus likely represents the winter selection pressure. We also have extensive data concerning the periods of activity of this bee during the spring and summer, the foraging season. The length of the foraging season is dictated in part by the magnitude of degree-days in base 14°C, the threshold temperature of activity. Eleven potential sites where X.v. virginica populations are not currently known to exist were analysed for winter and summer temperature shifts using scenarios for the years 2050 and 2100 in the Canadian Global Climate Model. These sites were chosen for their representativeness of geographic distribution from the western extent of the Great Lakes, to the Maritimes. Overall, the increase in winter temperatures, already of import to Canadian ecology, was found to be more directly influential than spring temperatures. In the best case of global warming, the range of X.v. virginica may increase to two new locales out of the analysed eleven. However, in the worst case of warming, this species’ range may increase to ten out of the eleven sites, from Duluth, Michigan (western Lake Superior) to Halifax, Nova Scotia (Maritimes).
Bees as
Bio-Indicators for Oak Savannah Restoration
Alana Taylor* and Laurence Packer
The
purpose of my study is to examine the changes in bee communities since the
restoration of various oak savannah habitats in southern Ontario over the past
20 years. As habitats become
increasingly fragmented, ways of rapidly determining which habitats to conserve
is becoming more and more essential. One
method to approach this problem is the use of indicator taxa to determine
biodiversity in an ecosystem. In theory,
the diversity of the indicator taxa should reflect the diversity and state of
other species within the given ecosystem (Kerr et al., 2000). Bees have been chosen as the indicator taxa for this study
for two reasons: (1) they are highly prone to extinction (Zayed and Packer 2005) and (2)
they are a vital part almost all
terrestrial ecosystems as most habitat
conservation depends on the presence of pollinators
(Michener, 2000). (Conservation Biology)
Interval
Timing by Foraging Bumble Bees, Bombus
impatiens
Anthea J. Veal*, Michael J. Boisvert and David F. Sherry
Interval
timing mechanisms are assumed to function in the foraging domain, however, they
are usually examined in artificial operant contexts. In experiments with bumble
bees, a high-quality floral reward became available after a fixed delay elapsed
since the initiation of a foraging bout in another patch. Bees were trained to
forage in a screened enclosure that contained 13 artificial flowers. At the
start of a trial, twelve flowers contained a small volume of 25% sucrose
reward, the remaining flower was empty. Either 60 s or 90 s after the first
reward was taken, the HQ flower filled with a large volume of 50% sucrose
reward. Bees scheduled visits to the HQ flower sooner when the delay was 60 s
than when it was 90 s and the times of visits to the HQ flower corresponded
closely to the delay. These findings extend earlier demonstrations of interval
timing by bumble bees trained on fixed interval schedules, and suggest that
bees can also time intervals in the minutes range while foraging. (Behavioral
Ecology)
Size-dependent
female mate copying in the guppy (Poecilia
reticulata)
Jelena Vukomanovic* & F. Helen Rodd
Previous
work on guppies has shown that small females copy the mate choice decisions of larger
females, but not vice versa. We extended this work to ask, when put in a
situation where they have little information available to distinguish between
males, whether large females will also copy large females, and small females
will copy small ones. Using Dugatkin's (1992) criteria, we found that both
small and large females will copy the mate choice decisions of large females,
but that neither small nor large females copy small females. However, we did
not find evidence of mate copying using criteria used by other researchers. We
discuss possible explanations for our observations and we propose that the
advantages of avoiding sexually transmitted parasites (e.g. Gyrodactylus turnbulli) could be
maintaining this pattern of copying behaviour. (Behavioral Ecology)