Do Active and Passive Antipredator Defences in the Toad Epidalea calamita Differ between Males and Females from Natural Habitats and Agrosystems?

Francisco Javier Zamora-Camacho

doi:10.3390/d13120614

Abstract

Due to their assumed costs, simultaneous antipredator strategies are expected to face trade-offs, which, however, could be milder in individuals subjected to a more intense predator pressure. In this work, I studied the relationship between locomotion and parotoid glands in the natterjack toad, Epidalea calamita. Specifically, I predicted that individuals with reduced sprint speed would rely more on their chemical defences, having larger and more aposematically coloured parotoid glands. In addition, I expected this trade-off to be more evident in females and toads from pine grove habitats, because, according to previous work, males and toads from agrosystems are under greater predator pressure. However, sprint speed showed no relationship with coloration, but toads with proportionally greater parotoid glands were also proportionally faster. Thus, the costs of these antipredator traits might not be high enough to make them interfere, or the benefits of simultaneous optimisation of sprint speed and parotoid gland size might outweigh the costs of it in some individuals. In any case, habitat and sex did not affect these relationships, so the trends detected are valid across sexes and the habitats studied.

Highlights

Failed predator attacks may damage fitness in diverse ways [5,6]: they might result in wounds and injuries of varying degrees of seriousness, which may lead to reduced mobility and greater susceptibility to future predator attacks [7], or to infections that may compromise health and survival [8]
The full model detected that the residuals of sprint speed on SVL were greater in The fullinmodel detected that the residuals sprint speedofonparotoid
1, 85 = 4.049; p = 0.047) were significant. These results challenge both the fundamental predictions on which this work was These results challenge both the fundamental predictions on which this work was based. They provide no evidence of a trade-off between sprint speed and based

Summary

Introduction

Predators are major agents of selection on their prey [1,2]. First and foremost, the future fitness of an individual that is preyed on is reduced to zero [3,4]. Failed predator attacks may damage fitness in diverse ways [5,6]: they might result in wounds and injuries of varying degrees of seriousness, which may lead to reduced mobility and greater susceptibility to future predator attacks [7], or to infections that may compromise health and survival [8]. Predator threats can promote the expression of inducible antipredator defences that, be they behavioural [9], physical [10], or chemical [11], usually come with costs, primarily in terms of time [12] or energy consumption [13]

Methods

Results

Conclusion