Life Sciences Commons^™

A Kin-Selection Model Of Fairness In Heterogeneous Populations, Geoff Wild, Veronica J. Flear, Graham J. Thompson

Biology Publications

Humans and other primates exhibit pro-social preferences for fairness. These preferences are thought to be reinforced by strong reciprocity, a policy that rewards fair actors and punishes unfair ones. Theories of fairness based on strong reciprocity have been criticized for overlooking the importance of individual differences in socially heterogeneous populations. Here, we explore the evolution of fairness in a heterogeneous population. We analyse the Ultimatum Game in cases where players’ roles in the game are determined by their status. Importantly, our model allows for non-random pairing of players, and so we also explore the role played by kin selection in …

Long-Term Winter-Site Fidelity In Song Sparrows (Melospiza Melodia), Tosha R. Kelly, Keith A. Hobson, Garth @. Casbourn, Elizabeth A. Macdougall-Shackleton, Scott A. Macdougall-Shackleton

Biology Publications

In migratory animals, the degree to which individuals return to the same wintering sites across multiple years can affect fitness and population dynamics, and thus has important implications for conservation. Despite this, long-term evaluations of wintering-site fidelity are rare for migratory birds: many populations are intensively studied on their breeding grounds but tracking the migratory movements of small birds once they leave the breeding grounds is challenging. To evaluate patterns of overwintering location and fidelity, we collected winter-grown claw tissue from 301 Song Sparrows (Melospiza melodia; 449 samples) captured in spring at their breeding grounds over six consecutive …

No Evidence That Songbirds Use Odour Cues To Avoid Malaria-Infected Conspecifics, Leanne A. Grieves, Elizabeth A. Macdougall-Shackleton

Biology Publications

Many animals have evolved mechanisms to detect and avoid parasitized conspecifics, primarily through odour cues, but whether birds are capable of odour-mediated parasite avoidance is unknown. Recently, we showed that exposing song sparrows (Melospiza melodia) to avian malaria parasites (Plasmodium sp.) alters the chemical composition of their preen oil, which is the major source of body odour in birds. Here, we presented song sparrows with preen oil from uninfected (sham-inoculated) and malaria-infected conspecifics, predicting that birds would spend more time with odour cues from uninfected than infected birds. Birds without detectable malarial infections spent about 50% more …

Seasonal Migration Distance Varies With Natal Dispersal And Predicts Parasitic Infection In Song Sparrows, Tosha R. Kelly, Heather L. Macgillivray, Yanina Sarquis-Adamson, Matthew J. Watson, Keith A. Hobson, Elizabeth A. Macdougall-Shackleton

Biology Publications

Seasonal migration and natal dispersal represent the major large-scale movements in the lives of animals. Individuals that are relatively prone to movement and exploration might thus be more likely to disperse and also to migrate farther. Such movement might be either negatively associated with parasitic infection (if infection prevents hosts from successful long-distance migration) or positively associated (e.g. if longer-distance migrants encounter more abundant or more diverse parasites). We examined whether natal dispersal tendency predicts seasonal migration distance in song sparrows (Melospiza melodia) and whether migration distance predicts infection with bloodborne parasites upon arrival at the breeding grounds. …

Fear Of Large Carnivores Is Tied To Ungulate Habitat Use: Evidence From A Bifactorial Experiment, Haley K. Epperly, Michael Clinchy, Liana Y. Zanette, Robert A. Mcceery

Biology Publications

The fear large carnivores inspire in large ungulates has been argued to have cascading effects down food webs. However, a direct link between ungulate habitat use and their fear of large carnivores has not been experimentally tested. To fill this critical gap, we conducted a bi-factorial experiment in an African savanna. We removed shrub cover and broadcast large carnivore vocalizations (leopard, hyena, dog) or non-threatening control vocalizations in both experimentally cleared and shrubby control sites. We recorded the proactive (frequency of visitation) and reactive (fleeing or vigilance) responses of multiple prey (impala, warthog, nyala and bushbuck). Critically, we found a …

Erratum: Publisher Correction: Fear Of Large Carnivores Is Tied To Ungulate Habitat Use: Evidence From A Bifactorial Experiment (Scientific Reports (2021) 11 1 (12979)), Haley K. Epperly, Michael Clinchy, Liana Y. Zanette, Robert A. Mccleery

Biology Publications

No abstract provided.

Fear Of Predators In Free-Living Wildlife Reduces Population Growth Over Generations, Marek C. Allen, Michael Clinchy, Liana Y. Zanette

Biology Publications

Data set for article in Fear of predators in free ‐ living wildlife reduces population growth over generations

in

Proceedings of the National Academy of Sciences of the United States of America

Epigenetic Memories And The Evolution Of Infectious Diseases, Geoff Wild

Biology Publications

Genes with identical DNA sequence may show differential expression because of epigenetic marks. Where epigenetic marks respond to past conditions, they represent a form of “memory”. Despite their medical relevance, the impact of memories on the evolution of infectious diseases has rarely been considered. Here we explore the evolution of virulence in pathogens that carry memories of the sex of their previous host. We show that this form of memory provides information about the sex of present and future hosts when the sexes differ in their pathogen’s transmission pattern. Memories of past hosts enable the evolution of greater virulence in …

Persistence Of Diet Effects On The Drosophila Suzukii Microbiota, Yanira Jiménez Padilla, Ebenezer Esan, Kevin D. Floate, Brent J. Sinclair

Biology Publications

The insect commensal microbiota consists of prokaryotes and eukaryotes. The effect of diet and the persistence of the gut microbiota in Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) are not well-understood. We transferred subsets of a single population of D. suzukii to different fruit-based diets (blueberry, raspberry, and strawberry) for three generations and then returned them to a common, banana-based, laboratory diet. We used 16S (bacteria) and ITS (fungi) sequencing of female endosymbiont-free flies to identify the microbiota. We identified 2700 bacterial and 350 fungal OTUs; there was no correlation between the number of bacterial and fungal OTUs in a sample. Bacterial …

Reversing Sodium Differentials Between The Hemolymph And Hindgut Speeds Chill Coma Recovery But Reduces Survival In The Fall Field Cricket, Gryllus Pennsylvanicus, Jacqueline E. Lebenzon, Lauren E. Des Marteaux, Brent J. Sinclair

Biology Publications

Chill-susceptible insects enter the reversible state of chill coma at their critical thermal minimum (CT_min­). During chill coma, movement of Na⁺ and water from the hemolymph to the gut lumen disrupt ion and water balance. Recovery from cold exposure requires re-establishment of this balance, and failure to do so results in chilling injury or death. We hypothesized that the passive leak of Na⁺ and consequently water during cold exposure is driven by the [Na⁺] differential between the gut and hemolymph. To determine the extent to which this [Na⁺] differential affects cold …

Dissection Of Anoplophora Glabripennis (Coleoptera: Cerambycidae) Larval Tissues For Physiological And Molecular Studies, Alex S. Torson, Lauren E. Des Marteaux, Susan Bowman, Meng Lei Zhang, Kevin Ong, Daniel Doucet, Brent J Sinclair, Amanda D. Roe

Biology Publications

Many biological processes are partitioned among organs and tissues, necessitating tissue-specific or organ-specific analysis (particularly for comparative -omics studies). Standardised techniques for tissue identification and dissection are therefore imperative for comparing among studies. Here we describe dissection protocols for isolating six key tissues/organs from larvae of the Asian longhorned beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae): the supraoesophageal ganglion, posterior midgut, hindgut, Malpighian tubules, fat body, and thoracic muscle. We also describe how to extract haemolymph and preserve whole larvae for measurements such as protein, lipid, and carbohydrate content. We include dissection protocols for both fresh-killed and previously frozen specimens. Although …

A Comparison Of Low Temperature Biology Of Pieris Rapae From Ontario, Canada, And Yakutia, Far Eastern Russia, Natalia G. Li, Jantina Toxopeus, Martin Moos, Jesper G. Sørensen, Brent J. Sinclair

Biology Publications

Low temperatures limit the distribution and abundance of ectotherms. However, many insects can survive low temperatures by employing one of two cold tolerance strategies: freeze avoidance or freeze tolerance. Very few species can employ both strategies, but those that do provide a rare opportunity to study the mechanisms that differentiate freeze tolerance and freeze avoidance. We showed that overwintering pupae of the cabbage white butterfly Pieris rapae can be freeze tolerant or freeze avoidant. A population of P. rapae in northeastern Russia (Yakutsk) froze at c. -9.3 °C and were freeze-tolerant in 2002-2003 when overwintered outside. However, P. rapae from …

Thermal Variability And Plasticity Drive The Outcome Of A Host-Pathogen Interaction, Laura V. Ferguson, Brent J. Sinclair

Biology Publications

Variable, changing, climates may affect each participant in a biotic interaction differently. We explored the effects of temperature and plasticity on the outcome of a host-pathogen interaction to try to predict the outcomes of infection under fluctuating temperatures. We infected Gryllus veletis crickets with the entomopathogenic fungus Metarhizium brunneum under constant (6 °C, 12 °C, 18 °C or 25 °C) or fluctuating temperatures (6 °C to 18 °C or 6 °C to 25 °C). We also acclimated crickets and fungi to constant or fluctuating conditions. Crickets acclimated to fluctuating conditions survived best under constant conditions if paired with warm-acclimated fungus. …

Humans, But Not Their Dogs, Displace Pumas From Their Kills: An Experimental Approach, Justin P. Suraci, Justine A. Smith, Michael Clinchy, Liana Y. Zanette, Christopher C. Wilmers

Biology Publications

Domestic dogs are the most abundant large carnivore on the planet, and their ubiquity has led to concern regarding the impacts of dogs as predators of and competitors with native wildlife. If native large carnivores perceive dogs as threatening, impacts could extend to the community level by altering interactions between large carnivores and their prey. Dog impacts may be further exacerbated if these human-associated predators are also perceived as indicators of risk from humans. However, observational approaches used to date have led to ambiguity regarding the effects of dog presence on wildlife. We experimentally quantified dog impacts on the behavior …

Thermal Limits Of Summer-Collected Pardosa Wolf Spiders (Araneae: Lycosidae) From The Yukon Territory And Greenland, Susan E. Anthony, Christopher M. Buddle, Toke T. Høye, Brent J. Sinclair

Biology Publications

Arctic and sub-Arctic terrestrial ectotherms contend with large daily and seasonal temperature ranges. However, there are few data available on the thermal biology of these high-latitude species, especially arachnids. We determined the lower and upper thermal limits of seven species of wolf spider from the genus Pardosa (Araneae: Lycosidae) collected in summer from the Yukon Territory (Canada) and Southern Greenland. None of these species survived freezing, and while spiderlings appeared freeze-avoidant, surviving to their supercooling point (SCP, the temperature at which they spontaneously freeze), chill-susceptible adults and juveniles died at temperatures above their SCP. The critical thermal minimum (CTmin, the …

Fear Of Humans As Apex Predators Has Landscape-Scale Impacts From Mountain Lions To Mice, Justin P. Suraci, Michael Clinchy, Liana Y. Zanette, Christopher C. Wilmers

Biology Publications

Apex predators such as large carnivores can have cascading, landscape-scale impacts across wildlife communities, which could result largely from the fear they inspire, although this has yet to be experimentally demonstrated. Humans have supplanted large carnivores as apex predators in many systems, and similarly pervasive impacts may now result from fear of the human ‘super predator’. We conducted a landscape-scale playback experiment demonstrating that the sound of humans speaking generates a landscape of fear with pervasive effects across wildlife communities. Large carnivores avoided human voices and moved more cautiously when hearing humans, while medium-sized carnivores became more elusive and reduced …

Playback Of Predator Calls Inhibits And Delays Dawn Singing In A Songbird Community, Peter Santema, Mihai Valcu, Michael Clinchy, Liana Zanette, Bart Kempenaers

Biology Publications

Recent studies have demonstrated that experimental increases in perceived predation risk can substantially impair breeding behavior and reduce reproductive success. Perceived predation risk may also occur in the context of sexual signaling, with potential consequences for sexual selection. In songbirds, singing at dawn is an important sexual signal but may also attract predators. Here, we report on 2 experiments designed to test whether perceived predation risk affects the occurrence and timing of dawn singing in a songbird community. In a pilot experiment, we broadcast predator playbacks intermittently across half a forest plot and nonpredator playbacks across the other half throughout …

Gut Yeasts Do Not Improve Desiccation Survival In Drosophila Melanogaster, Joanne M. Tang, Yanira Jiménez Padilla, Marc-André Lachance, Brent J. Sinclair

Biology Publications

A healthy gut microbiota generally improves the performance of its insect host. Although the effects can be specific to the species composition of the microbial community, the role of gut microbiota in determining water balance has not been well explored. We used axenic and gnotobiotic (reared with a known microbiota) Drosophila melanogaster to test three hypotheses about the effects of gut yeasts on the water balance of adult flies: 1) that gut yeasts would improve desiccation survival in adult flies; 2) that larval yeasts would improve adult desiccation survival; 3) that the effects would be species-specific, such that yeasts closely …

Overwintering Red Velvet Mites Are Freeze Tolerant, Susan E. Anthony, Brent J. Sinclair

Biology Publications

Although many arthropods are freeze tolerant (able to withstand internal ice), small-bodied terrestrial arthropods such as mites are thought to be constrained to freeze avoidance. We field-collected active adult red velvet mites, Allothrombium sp. (Trombidiidae), in winter in Southwestern Ontario, Canada, where temperatures drop below −20°C. These mites froze between −3.6° and −9.2°C and survived internal ice formation. All late-winter mites survived being frozen for 24 h at −9°C, and 50% survived 1 wk. The lower lethal temperature (LLT50; low temperature that kills 50% of mites) was ca. −20°C in midwinter. Hemolymph osmolality and glycerol concentration increased in midwinter, accompanied …

Loss Of Ion Homeostasis Is Not The Cause Of Chill Coma Or Impaired Dispersal In False Codling Moth Thaumatotibia Leucotreta (Lepidoptera: Tortricidae), Minette Karsten, Jacqueline E. Lebenzon, Brent J. Sinclair, John S. Terblanche

Biology Publications

Dispersal is a central requirement of a successful sterile insect release programme, but field-released false codling moth (FCM) typically suffer from poor dispersal ability, especially at low ambient temperatures. Here we test the hypothesis that poor activity and dispersal in FCM is caused by delayed or perturbed recovery of ion and/or water homeostasis after chilling for handling and transport prior to field release. Hemolymph and flight muscle were collected from two treatment groups at three time points that targeted thermal conditions above and below the chill coma induction threshold of ~ 6 °C: 1) control moths kept at 25 °C, …

How Crickets Become Freeze Tolerant: The Transcriptomic Underpinnings Of Acclimation In Gryllus Veletis, Jantina Toxopeus, Lauren E. Des Marteaux, Brent J. Sinclair

Biology Publications

Some ectotherms can survive internal ice formation. In temperate regions, freeze tolerance is often induced by decreasing temperature and/or photoperiod during autumn. However, we have limited understanding of how seasonal changes in physiology contribute to freeze tolerance, and how these changes are regulated. During a six week autumn-like acclimation, late-instar juveniles of the spring field cricket Gryllus veletis (Orthoptera: Gryllidae) become freeze tolerant, which is correlated with accumulation of low molecular weight cryoprotectants, elevation of the temperature at which freezing begins, and metabolic rate suppression. We used RNA-Seq to assemble a de novo transcriptome of this emerging laboratory model for …

Incorporating Temperature And Precipitation Extremes Into Process-Based Models Of African Lepidoptera Changes The Predicted Distribution Under Climate Change, Madeleine G. Barton, John S. Terblanche, Brent J. Sinclair

Biology Publications

Terrestrial insects are responding to ongoing climate change. While these responses have been primarily linked to rising temperatures, insects are sensitive to desiccation, and the impacts of altered precipitation regimes remain relatively unexplored. Here, we develop a mechanistic model of survival and performance responses to both temperature and desiccation stress, focussing on Lepidoptera in Africa, where a general understanding of such responses to climate change is urgently required. We run the model with climate data from general circulation models at daily time intervals under current (2011–2015) and projected future (2046–2050) climate scenarios. We first simulate four hypothetical, but typical, Lepidoptera …

Laboratory Acclimation To Autumn-Like Conditions Induces Freeze Tolerance In The Spring Field Cricket Gryllus Veletis (Orthoptera: Gryllidae), Jantina Toxopeus, Alexander H. Mckinnon, Tomáš Štětina, Kurtis F. Turnbull, Brent J Sinclair

Biology Publications

Many temperate insects encounter temperatures low enough to freeze their body fluids. Remarkably, some insects are freeze-tolerant, surviving this internal ice formation. However, the mechanisms underlying freeze tolerance are not well-understood, in part due to a lack of tractable model organisms. We describe a novel laboratory model to study insect freeze tolerance, the spring field cricket Gryllus veletis (Orthopera: Gryllidae). Following acclimation to six weeks of decreasing temperature and photoperiod, G. veletis become freeze-tolerant, similar to those exposed to natural autumn conditions in London, Ontario, Canada. Acclimated crickets suppress their metabolic rate by c. 33%, and survive freezing for up …

Mechanisms Underlying Insect Freeze Tolerance., Jantina Toxopeus, Brent J Sinclair

Biology Publications

Freeze tolerance - the ability to survive internal ice formation - has evolved repeatedly in insects, facilitating survival in environments with low temperatures and/or high risk of freezing. Surviving internal ice formation poses several challenges because freezing can cause cellular dehydration and mechanical damage, and restricts the opportunity to metabolise and respond to environmental challenges. While freeze-tolerant insects accumulate many potentially protective molecules, there is no apparent 'magic bullet' - a molecule or class of molecules that appears to be necessary or sufficient to support this cold-tolerance strategy. In addition, the mechanisms underlying freeze tolerance have been minimally explored. Herein, …

The Effect Of Cold Acclimation On Active Ion Transport In Cricket Ionoregulatory Tissues., Lauren E Des Marteaux, Soheila Khazraeenia, Gil Y Yerushalmi, Andrew Donini, Natalia G Li, Brent J Sinclair

Biology Publications

Cold-acclimated insects defend ion and water transport function during cold exposure. We hypothesized that this is achieved via enhanced active transport. The Malpighian tubules and rectum are likely targets for such transport modifications, and recent transcriptomic studies indicate shifts in Na+-K+ ATPase (NKA) and V-ATPase expression in these tissues following cold acclimation. Here we quantify the effect of cold acclimation (one week at 12 °C) on active transport in the ionoregulatory organs of adult Gryllus pennsylvanicus field crickets. We compared primary urine production of warm- and cold-acclimated crickets in excised Malpighian tubules via Ramsay assay at a range of temperatures …

Effects Of Cold Acclimation On Rectal Macromorphology, Ultrastructure, And Cytoskeletal Stability In Gryllus Pennsylvanicus Crickets., Lauren E Des Marteaux, Joseph R Stinziano, Brent J Sinclair

Biology Publications

Cold-acclimated insects maintain ion and water balance in the cold, potentially by reducing permeability or increasing diffusion distance across ionoregulatory epithelia such as the rectum. We explored whether cold acclimation induces structural modifications that minimize water and ion diffusion across the rectum and maintain rectal cell integrity. We investigated rectal structure and cytoskeletal stability in chill-susceptible adult Gryllus pennsylvanicus crickets acclimated for one week to either warm (25 °C) or cold (12 °C) conditions. After acclimation, we used light and transmission electron microscopy to examine rectal macromorphology and rectal pad paracellular ultrastructure. We also used fluorescence microscopy and a filamentous-actin …

Seasonal Shifts In The Insect Gut Microbiome Are Concurrent With Changes In Cold Tolerance And Immunity, Laura V. Ferguson, Pranav Dhakal, Jacqueline E. Lebenzon, David E. Heinrichs, Carol Bucking, Brent Sinclair

Biology Publications

1. Seasonal changes in the environment, such as varying temperature, have the potential to change the functional relationship between ectothermic animals, such as insects, and their microbiomes. Our objectives were to determine: (a) whether seasonal changes in temperature shift the composition of the insect gut microbiome, and (b) whether changes in the microbiome are concomitant with changes in the physiology of the host, including the immune system and response to cold.
2. We exposed laboratory populations of the spring field cricket, Gryllus veletis (Orthoptera: Gryllidae), to simulated overwintering conditions in both a laboratory microcosm and a field‐like microcosm containing soil and leaves. …

Too Important To Tamper With: Predation Risk Affects Body Mass And Escape Behaviour But Not Escape Ability, Benjamin T. Walters, Tin Nok Natalie Cheng, Justin Doyle, Chistopher G. Guglielmo, Michael Clinchy, Liana Y. Zanette

Biology Publications

Escaping from a predator is a matter of life or death, and prey are expected to adaptively alter their physiology under chronic predation risk in ways that may affect escape. Theoretical models assume that escape performance is mass dependent, whereby scared prey strategically maintain an optimal body mass to enhance escape. Experiments testing the mass-dependent predation risk hypothesis have demonstrated that prior experience of predation risk can affect body mass, and the behavioural decisions about evasive actions to take. Other studies on natural changes in body mass indicate that mass can affect escape. No single experiment has tested if all …

Insect Immunity Varies Idiosyncratically During Overwintering., Laura V Ferguson, Brent J Sinclair

Biology Publications

Overwintering insects face multiple stressors, including pathogen and parasite pressures that shift with seasons. However, we know little of how the insect immune system fluctuates with season, particularly in the overwintering period. To understand how immune activity changes across autumn, winter, and spring, we tracked immune activity of three temperate insects that overwinter as larvae: a weevil (Curculio sp., Coleoptera), gallfly (Eurosta solidaginis, Diptera), and larvae of the lepidopteran Pyrrharctia isabella. We measured baseline circulating hemocyte numbers, phenoloxidase activity, and humoral antimicrobial activity, as well as survival of fungal infection and melanization response at 12°C and 25°C to capture any …

Thermal Preference And Performance In A Sub-Antarctic Caterpillar: A Test Of The Coadaptation Hypothesis And Its Alternatives., Tanya M Haupt, Brent J Sinclair, Steven L Chown

Biology Publications

Physiological ecologists have long assumed that thermoregulatory behaviour will evolve to optimise physiological performance. The coadaptation hypothesis predicts that an animal's preferred body temperature will correspond to the temperature at which its performance is optimal. Here we use a strong inference approach to examine the relationship between thermal preference and locomotor performance in the caterpillars of a wingless sub-Antarctic moth, Pringleophaga marioni Viette (Tineidae). The coadaptation hypothesis and its alternatives (suboptimal is optimal, thermodynamic effect, trait variation) are tested. Compared to the optimal movement temperature (22.5°C for field-fresh caterpillars and 25, 20, 22.5, 25 and 20°C following seven day acclimations …