Force and Boldness: Cumulative Assets of a Successful Crayfish Invader

Lucian Pârvulescu,Kristian Miok,Ioan Marcu,Dan Ioan Stoia,Oana Maria Aburel,Mihajel Vereş,Mirela Danina Muntean,Melania Sterie,Adela Estera Puha,Mihaela Constanţa Ion

doi:10.3389/fevo.2021.581247

Abstract

Multiple causes can determine the disturbance of natural equilibrium in a population of a species, with a common one being the presence of invasive competitors. Invasives can drive native species to the resettlement of the trophic position, changing reproduction strategies or even daily normal behaviours. Here, we investigated the hypothesis that more effective anatomical features of an intruder (Faxonius limosus) come with increased boldness behaviour, contributing to their invasion success in competition against the native species (Pontastacus leptodactylus). We tested the boldness of specimens representing the two species by video-based assessment of crayfish individuals’ attempts to leave their settlement microenvironment. The experiment was followed by a series of measurements concerning chelae biometry, force and muscle energetics. The native species was less expressive in terms of boldness even if it had larger chelae and better muscular tissue performance. In contrast, because of better biomechanical construction of the chelae, the invasive species was capable of twice superior force achievements, which expectedly explained its bolder behaviour. These findings suggest that, in interspecific agonistic interactions, the behaviour strategy of the invasive crayfish species is based on sheer physical superiority, whereas the native crayfish relies on intimidation display.

Highlights

Biological invasions are one of the most challenging issues for nowadays conservationists (Nentwig et al, 2018; Flood et al, 2020)
The invasive crayfish F. limosus was more confident than the native P. leptodactylus, taking more risks as demonstrated by our laboratory experiments
The species F. limosus exhibited superior values of every parameter except those related to body size, emphasising the differences observed from a biomechanical point of view

Summary

Introduction

Biological invasions are one of the most challenging issues for nowadays conservationists (Nentwig et al, 2018; Flood et al, 2020). Multiple perspectives have been approached to understand and depict the processes behind successful invasions, such as ecological (Lodge, 1993; South et al, 2020), economical (Perrings et al, 2002), or pathological (Strauss et al, 2012) ones. Eco-behavioural perspectives might allow more insights into the complex process of biological invasions. We Invasion Driven by Force addressed the hypothesis that a successful crayfish invader is driven by its own bolder behaviour against shyness of the native resident. We used behaviour, morpho-mechanical and bioenergetic approaches

Objectives

Methods

Conclusion