Chronology of reproductive investment determines predation risk aversion in a felid-ungulate system.

Daniel A Crawford,Michael J Cherry,Richard B Chandler,David B Shindle,Brian D Kelly,Elina P Garrison,Karl V Miller,L Mike Conner

doi:10.1002/ece3.4947

Abstract

Fear of predators can behaviorally mediate prey population dynamics, particularly when predation risk influences reproductive investment. However, the costs of reproductive investment may mitigate predation risk aversion relative to periods when the link between reproductive output and prey behavior is weaker.We posit that intensity of reproductive investment in ungulates may predict their response to predation risk such that the sexes increase risk exposure during biological seasons that are pivotal to reproductive success, such as the fawn‐rearing and breeding seasons for females and males, respectively.We examined the activity patterns of sympatric white‐tailed deer (Odocoileus virginianus), a sexually segregated polygynous ungulate, and Florida panthers (Puma concolor coryi) in the context of the “risky times – risky places hypothesis” and the reproductive strategy hypothesis. We compared detection rates and diel activity overlap of both species using motion‐triggered camera traps positioned on (n = 120) and off (n = 60) anthropogenic trails across five reproductive seasons.Florida panthers were nocturnal and primarily observed on‐trail providing an experimental framework with risky times and risky places. Contrary to studies in other taxa inversely correlating prey reproductive investment to predation risk, the sexes of deer were more risk prone during sex‐specific seasons associated with intense reproductive investment.Our results suggest spatiotemporally variable predation risk influences sex‐specific behavioral decision‐making in deer such that reproductive success is maximized.

Highlights

Predators impact prey populations directly through mortality or indirectly through nonconsumptive predation risk effects
Our results provide strong correlative evidence that risk of predation by panthers induces white‐tailed deer activity patterns that are substantially different from activity patterns in other parts of their range where panthers do not occur
Increases in nocturnal activity of deer exposed to human hunting pressure are well documented (Kilgo, Labisky, & Fritzen, 1998; Kilpatrick & Lima, 1999; Little et al, 2015; Webb, Gee, Strickland, Demarais, & DeYoung, 2010)

Summary

| INTRODUCTION

Predators impact prey populations directly through mortality or indirectly through nonconsumptive predation risk effects. In addition to affecting morphology and physiological processes, predators influence prey behavior as individuals attempt to optimize foraging such that energetic intake is maximized and risk is minimized. Many hypotheses attempt to explain the behavioral differences between the sexes, but a generalizable consensus regarding drivers of demographically variable behavior is lacking as a result of the context‐specific factors (i.e., predator community, habitat composition) affecting ungulate species (Bleich, Bowyer, & Wehausen, 1997; Festa‐Bianchet, 2012; Pérez-Barbería, Robertson, & Gordon, 2005). Male breeding success and maternal investment are cornerstones of fitness; predation risk must be considered to understand ungulate fitness as both sexes attempt to optimize energetic intake under risk of predation according to their respective reproductive physiologies and energetic demands. We predicted that males would be most risk prone during the breeding season

| METHODS

| DISCUSSION

Findings

CONFLICT OF INTEREST