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Full-Text Articles in Life Sciences

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 Dec 2019

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 Nov 2019

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 Oct 2019

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 Sep 2019

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 Jul 2019

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 Apr 2019

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 Mar 2019

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 Mar 2019

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 Feb 2019

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 Jan 2019

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 …