Adrenal hormones likely affect anti-predator behavior in animals. With experimental field studies, we first investigated associations between mean fecal glucocorticoid metabolite (fGC) excretion and vigilance and with behavioral responses to alarm call playbacks in free-ranging meerkats (Suricata suricatta). We then tested how vigilance and behavioral responses to alarm call playbacks were affected in individuals administered exogenous cortisol. We found a positive association between mean fGC concentrations and vigilance behavior, but no relationship with 2 the intensity of behavioral responses to alarm calls. However, in response to alarm call playbacks, individuals administered cortisol took slightly longer to resume foraging than control individuals treated with saline solution. Vigilance behavior, which occurs in the presence and absence of dangerous stimuli, serves to detect and avoid potential dangers, whereas responses to alarm calls serve to avoid immediate predation. Our data show that mean fGC excretion in meerkats was associated with vigilance, as a re-occurring anti-predator behavior over long time periods, and experimentally induced elevations of plasma cortisol affected the response to immediate threats. Together, our results indicate an association between the two types of anti-predator behavior and glucocorticoids, but that the underlying mechanisms may differ. Our study emphasizes the need to consider appropriate measures of adrenal activity specific to different contexts when assessing links between stress physiology and different anti-predator behaviors.

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Vicariant geographic isolation and resource partitioning have long been independently identified as processes contributing to the morphological divergence of closely-related species. However, little is known about the extent to which vicariant history influences the adaptive ecological divergence associated with resource partitioning and trophic specialization within species. The present study thus quantified the contribution of vicariant historical genetic divergence to the adaptive contemporary morphological divergence of intraspecific feeding specialists in the Rainbow smelt (Pisces: Osmerus mordax). This species is characterized by the polyphyletic origin of two lacustrine feeding specialists originating in two intraspecific lineages associated with independent glacial refuges. The historical genetic segregation was initiated approximately 350 000 years ago, whereas the lacustrine trophic segregation arose within the past 10 000 years. Wild caught lacustrine smelt populations were grouped a priori based on known historical genetic identities (Acadian and Atlantic mitochondrial DNA clades) and contemporary feeding specializations (microphageous and macrophageous morphotypes). The present study demonstrated that independent suites of correlated morphological traits are associated with either vicariant history or contemporary feeding specializations. Second, functionally-similar feeding specialists exhibit distinct morphologies resulting largely from vicariant historical processes. Although, the evolutionary processes producing historical phenotypes remains unknown, the results obtained demonstrate how adaptive radiation associated with ecological resource partitioning and feeding specializations can be strongly influenced by intraspecific phenotypic diversification resulting from relatively recent vicariant histories.

Entre les années 1960 et 1980, la pêche récréative hivernale au Québec est graduellement passée d’une pratique marginale à une activité souvent structurée et prenant la forme de villages de pêche offrant parfois un service de location de cabanes. Malgré l’importance de cette activité, la pêche hivernale demeure peu étudiée comparativement à la pêche estivale. Cet article présente un portrait actualisé de la pêche hivernale au Québec. Les principales espèces recherchées par les pêcheurs sportifs en hiver sont le doré jaune, le doré noir, la perchaude, le grand brochet, le poulamon atlantique et l’éperlan arc-en-ciel. Dans les systèmes du fleuve Saint-Laurent, de l’estuaire et du golfe du Saint-Laurent, de leurs tributaires et du lac Champlain (baie Missisquoi), 132 sites de pêche hivernale ont été répertoriés en 2018-2019, totalisant environ 4 700 cabanes de pêche. Les informations disponibles sur la pêche hivernale dans certaines régions du Québec, particulièrement en eaux intérieures, demeurent toutefois incomplètes. La pêche hivernale présente de grandes possibilités de mise en valeur, mais elle engendre une pression de pêche qu’il importe de considérer dans la gestion des stocks de poissons au Québec.