Life History Responses of Four Invasive Crayfish Species Under Prolonged Suboptimal Temperatures

Area of Science:

• Ecology
• Invasive Species Biology
• Climate Change Ecology

Background:

• Temperature significantly influences poikilothermic organisms, affecting life-history traits and competitive interactions.
• Understanding how suboptimal temperatures modulate interactions among invasive species is crucial for predicting invasion outcomes.
• Comparative data on invasive crayfish performance under cold conditions is limited.

Purpose of the Study:

• To experimentally compare the growth, survival, and reproduction of the invasive marbled crayfish (Procambarus virginalis) with three other invasive North American crayfish species under suboptimal and fluctuating temperatures.
• To assess how single-species and mixed-species interactions are affected by prolonged cold periods followed by a temperature increase.
• To determine the species-specific competitive potential and resilience of invasive crayfish under altered thermal regimes.

Main Methods:

• Laboratory experiments involving marbled crayfish, spiny-cheek crayfish (Faxonius limosus), signal crayfish (Pacifastacus leniusculus), and red swamp crayfish (Procambarus clarkii).
• Species were cultured individually and in mixed stocks under prolonged suboptimal temperatures (~16°C for 45 weeks), followed by a short-term increase (~20°C).
• Growth, survival, and reproductive performance (glair gland formation, ovulation, hatching) were assessed across three independent trials.

Main Results:

• Marbled crayfish showed reduced growth at low temperatures but compensated, outperforming spiny-cheek crayfish in growth and survival.
• Marbled crayfish were suppressed by red swamp crayfish but showed temporary growth advantages with signal crayfish, leading to size convergence.
• Survival varied based on size, dominance, and aggression, with marbled crayfish exhibiting high survival in single-species groups. Reproductive development was temperature-constrained, with hatching only occurring after warming.

Conclusions:

• Suboptimal temperatures do not eliminate competitive asymmetries among invasive crayfish but alter invasion dynamics in species-specific ways.
• The marbled crayfish demonstrates resilience and competitive capacity in colder environments, influencing invasion potential under climate change.
• Understanding thermal influences on interspecific competition is vital for managing invasive species in a changing climate.