Predation Life History Responses to Increased Temperature Variability

Miguel Barbosa,Joao Pestana,Amadeu M V M Soares

doi:10.1371/journal.pone.0107971

Abstract

The evolution of life history traits is regulated by energy expenditure, which is, in turn, governed by temperature. The forecasted increase in temperature variability is expected to impose greater stress to organisms, in turn influencing the balance of energy expenditure and consequently life history responses. Here we examine how increased temperature variability affects life history responses to predation. Individuals reared under constant temperatures responded to different levels of predation risk as appropriate: namely, by producing greater number of neonates of smaller sizes and reducing the time to first brood. In contrast, we detected no response to predation regime when temperature was more variable. In addition, population growth rate was slowest among individuals reared under variable temperatures. Increased temperature variability also affected the development of inducible defenses. The combined effects of failing to respond to predation risk, slower growth rate and the miss-match development of morphological defenses supports suggestions that increased variability in temperature poses a greater risk for species adaptation than that posed by a mean shift in temperature.

Highlights

Temperature directly affects metabolic rate and energy expenditure
Our results indicate that predation risk has a significant effect on brood size (Table 1, Figure 1A)
Individuals reared under constant temperature, responded to increased predation risk by producing more neonates (Table 2, Figure 1A)

Summary

Introduction

Changes in temperature are often accompanied by both physiological and behavioural responses. One example of temperature change stress-induced disruption is the loss of the ability to recognize and respond to predation threat [1]. While organisms are typically able to cope with a natural rate of temperature change, increased variability in temperature is likely to impose additional physiological stress, potentially affecting the way organisms respond to environmental conditions. We address this issue by examining the effects of increased variation in temperature on life history responses to predation risk

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Conclusion