Watch Out for Your Neighbor: Climbing onto Shrubs Is Related to Risk of Cannibalism in the Scorpion Buthus cf. occitanus.

Francisco Sánchez-Piñero,Fernando Urbano-Tenorio,Ofer Ovadia

doi:10.1371/journal.pone.0161747

Francisco Sánchez-Piñero, Fernando Urbano-Tenorio + Show 1 more

Open Access

https://doi.org/10.1371/journal.pone.0161747

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Journal: PloS one	Publication Date: Sep 21, 2016
Citations: 8	License type: CC BY 4.0

Affiliation: University of Granada

Abstract

The distribution and behavior of foraging animals usually imply a balance between resource availability and predation risk. In some predators such as scorpions, cannibalism constitutes an important mortality factor determining their ecology and behavior. Climbing on vegetation by scorpions has been related both to prey availability and to predation (cannibalism) risk. We tested different hypotheses proposed to explain climbing on vegetation by scorpions. We analyzed shrub climbing in Buthus cf. occitanus with regard to the following: a) better suitability of prey size for scorpions foraging on shrubs than on the ground, b) selection of shrub species with higher prey load, c) seasonal variations in prey availability on shrubs, and d) whether or not cannibalism risk on the ground increases the frequency of shrub climbing. Prey availability on shrubs was compared by estimating prey abundance in sticky traps placed in shrubs. A prey sample from shrubs was measured to compare prey size. Scorpions were sampled in six plots (50 m x 10 m) to estimate the proportion of individuals climbing on shrubs. Size difference and distance between individuals and their closest scorpion neighbor were measured to assess cannibalism risk. The results showed that mean prey size was two-fold larger on the ground. Selection of particular shrub species was not related to prey availability. Seasonal variations in the number of scorpions on shrubs were related to the number of active scorpions, but not with fluctuations in prey availability. Size differences between a scorpion and its nearest neighbor were positively related with a higher probability for a scorpion to climb onto a shrub when at a disadvantage, but distance was not significantly related. These results do not support hypotheses explaining shrub climbing based on resource availability. By contrast, our results provide evidence that shrub climbing is related to cannibalism risk.

Highlights

Foraging animals balance resource finding and acquisition in response to food availability and predation risk [1], [2], [3]
Our results provide evidence that shrub climbing is related to cannibalism risk
Shrub Climbing by Buthus occitanus Scorpions behavior and spatial distribution [3], [4]

Summary

Introduction

Foraging animals balance resource finding and acquisition in response to food availability and predation risk [1], [2], [3]. Predation threat becomes an important factor determining where animals can feed safely, affecting trophic interactions as well as population and community structure [4], [5]. In predators with size-structured populations, cannibalism is usually an important interaction shaping the distribution, behavior, and population structure of these species [6], [7], [8]. Cannibalism is an asymmetric interaction usually involving a larger-sized predator feeding on smaller conspecifics [6]. Responses to avoid or minimize cannibalism such as the use of (micro-)habitats and activity periods that exhibit low risk of cannibalism may have evolved in cannibalistic species [10], [11]. Few studies have focused on whether cannibalism affects foraging behavior and microhabitat use [6], [9]

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