Survival, Growth, and Reproduction: Comparison of Marbled Crayfish with Four Prominent Crayfish Invaders

Abstract

Biological invasions are increasingly recognized ecological and economic threats to biodiversity and are projected to increase in the future. Introduced freshwater crayfish in particular are protruding invaders, exerting tremendous impacts on native biodiversity and ecosystem functioning, as exemplified by the North American spiny-cheek, signal and red swamp crayfish as well as the Australian common yabby. The marbled crayfish is among the most outstanding freshwater crayfish invaders due to its parthenogenetic reproduction combined with early maturation and high fecundity. As their introduced ranges expand, their sympatric populations become more frequent. The question of which species and under what circumstances will dominate in their introduced communities is of great interest to biodiversity conservation as it can offer valuable insights for understanding and prioritization of management efforts. In order to examine which of the aforementioned species may be more successful as an invader, we conducted a set of independent trials evaluating survival, growth, claw injury, and reproduction using single-species stocks (intraspecific interactions) and mixed stocks (interspecific interactions) of marbled crayfish vs. other crayfish invaders since the onset of exogenous feeding. In both single and mixed stocks, red swamp crayfish and yabby grew faster than marbled crayfish, while marbled crayfish were superior to both spiny-cheek and signal crayfish in terms of growth. With the exception of signal crayfish, the faster-growing species consistently reached a higher survival rate. The faster-growing species tended to negatively impair smaller counterparts by greater claw injury, delayed maturation, and reduced fecundity. Only marbled crayfish laid eggs as early as 14 weeks in this study, which is earlier than previously reported in the literature. Thus, the success of marbled crayfish among invasive crayfish is significantly driven by relatively fast growth as well as an early and frequent reproduction. These results shed light on how interactions between invasive populations can unfold when their expansion ranges overlap in the wild, thereby contributing to the knowledge base on the complex population dynamics between existing and emerging invasive species.

Physiological performance of native and invasive crayfish species in a changing environment: insights from Dynamic Energy Budget models

“…This is the case here as well: P. virginalis is the smallest species and can reproduce at much lower ( \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$f<0.3$\end{document} ) food availability than other species ( \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$f>0.4$\end{document} ). In line with our model, experimental studies recorded higher growth rates of P. virginalis juveniles over P. leniusculus ( Kouba et al , 2021 ). They also recorded consistently higher survival rates of P. virginalis in competitive trials.…”

“…The invasive P. leniusculus also has a considerably higher reproduction rate than the two native species, but still lags behind P. virginalis . The higher reproduction rates of invasive crayfish reflect current knowledge: successful crayfish invaders are in general competitively superior and exhibit higher fecundity, earlier maturation and broader tolerance to environmental stress ( Kouba et al , 2021 ), and may thus maintain higher reproductive output and earlier maturation even in suboptimal conditions of low food availability due to, e.g., competition in co-occurring populations, as shown in this study.…”

“…Besides through disease transmission, invasive crayfish often displace native European crayfish populations through competitive exclusion due to, among others, their broader physiological tolerance and advantageous life history traits ( Kouba et al , 2021 ). Thus, we used DEB models to identify main conservation issues with respect to food availability and expected increases in temperature due to climate change.…”

“…The simulated scaled food availability ( \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$f$\end{document} ) ranged from the value barely supporting maturation, to the value exceeding the theoretical maximum. Extremes of the range are ecologically less relevant: at low extremes the population would not grow, and values higher than \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$f=1$\end{document} are anomalous, but could explain large size of P. virginalis reported by Kouba et al ( 2021 ) and Vogt et al ( 2015 ). Effects of simulated levels in food availability varied between species, but a general trend can be observed, where the small P. virginalis belonging to Cambaridae responds to favorable environments by increasing its ultimate length by a much larger factor (+260%) compared with the three crayfish belonging to the Astacidae family (+114% to +150%).…”

“…The first of the two invasive crayfish species considered in the study, P. leniusculus , is the most successful crayfish invader of European freshwaters ( Kouba et al , 2014 ); the second species, P. virginalis , is the emerging invader and the only known obligatory parthenogenetic freshwater crayfish species ( Andriantsoa et al , 2019 ; Kouba et al , 2021 ; Vogt, 2020 ). Both invaders are potential vectors of crayfish plague, a disease caused by the oomycete pathogen Aphanomyces astaci , which is mostly lethal to native crayfish ( Martín-Torrijos et al , 2019 ).…”