Behavioral differences in an over‐invasion scenario: marbled vs. spiny‐cheek crayfish

Stefan M Linzmaier,Jonathan M Jeschke,Larissa S Goebel,Florian Ruland

doi:10.1002/ecs2.2385

Abstract

AbstractNew species often invade ecosystems already dominated by previous invaders. Ornamental freshwater crayfish, particularly parthenogenetic marbled crayfish (Procambarus virginalis), increasingly establish in European water bodies where they interact with resident native and non‐native species. Behavioral traits and behavioral syndromes can influence the outcome of these species interactions. The behavior of non‐native crayfish is often studied in notorious invaders but rarely in new and emerging species, although those provide the best opportunity for management. Activity, aggressiveness, and boldness have repeatedly been associated with invasion success and species displacement. Further, crayfish can adapt their behavior after they have established in the new range. We investigated whether marbled crayfish can displace the widely established spiny‐cheek crayfish (Orconectes limosus). Specifically, we compared their behavioral traits and evaluated whether these traits differ, using marbled crayfish populations from aquaria and the field and spiny‐cheek crayfish from the field. We staged agonistic encounters, measured activity levels, and recorded the response to a simulated threat of both species and both origins (field and aquarium) in laboratory trials. We found that in agonistic encounters, marbled crayfish were on average more aggressive than spiny‐cheek crayfish, even against larger opponents. Aggressiveness and activity were positively correlated, which is indicative for an aggression syndrome. Marbled crayfish from the field were less active than those from aquaria, but there was no difference in aggressiveness. Marbled crayfish often froze in response to a simulated threat, whereas spiny‐cheek crayfish reacted either offensively or defensively. These results from the laboratory illustrate potentially important behavioral mechanisms behind crayfish over‐invasions and show behavioral plasticity in a species where all known individuals are genetically identical. To better understand the invasion process in nature, the species’ reproductive biology and interactions with other members of the community should be considered. We conclude that the recent success of marbled crayfish in establishing new populations could be influenced by their behavioral flexibility and their potential to competitively persist in the presence of established invasive crayfish.

Highlights

Species invasions have already massively altered aquatic communities and are still increasing worldwide (Gallardo et al 2016, Seebens et al 2017)
Aggressiveness, and boldness have repeatedly been associated with invasion success and species displacement
We conclude that the recent success of marbled crayfish in establishing new populations could be influenced by their behavioral flexibility and their potential to competitively persist in the presence of established invasive crayfish

Summary

Introduction

Species invasions have already massively altered aquatic communities and are still increasing worldwide (Gallardo et al 2016, Seebens et al 2017). The consequences of multiple species invasions are largely unknown (Hewitt and Huxel 2002), but the invasion outcome and interaction strength between invading and resident species can be assessed by behavioral differences and correlated suites of behavioral traits (i.e., behavioral syndromes; Chapple et al 2012, Sih et al 2012, Penk et al 2017). Some behavioral traits such as activity, aggressiveness, and boldness have repeatedly been associated with invasion success (Weis 2010, Chapple et al 2012). Comparative studies across invading species can help elucidate what makes some invaders more successful than others (van Kleunen et al 2010)

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Discussion

Conclusion