Invasive Widow Spiders Perform Differently at Low Temperatures from Conspecifics from the Native Range

Area of Science:

• Ecology
• Evolutionary Biology
• Invasive Species Research

Background:

• Temperature is a critical factor influencing the success of non-native species.
• Thermal tolerance and plasticity are proposed mechanisms for successful invasions.
• Australian redback spiders (Latrodectus hasselti) provide a model for studying invasion dynamics.

Purpose of the Study:

• To test hypotheses regarding the role of plasticity and native thermal breadth in successful invasions.
• To compare thermal tolerance and behavioral traits between native (Australia) and invasive (Japan) redback spider populations.

Main Methods:

• Measured critical thermal minimum (CTmin) and maximum (CTmax) for both populations.
• Assessed egg development time and hatching success at 15°C and 25°C.
• Evaluated juvenile behavior (exploration, boldness) at different temperatures.

Main Results:

• Invasive spiders had a higher CTmin but similar CTmax compared to native spiders.
• Invasive eggs showed better performance across a wider temperature range (15°C and 25°C).
• Invasive juveniles displayed temperature-dependent behavioral plasticity (faster exploration, bolder at 15°C).

Conclusions:

• The invasive redback spider population demonstrates enhanced thermal breadth and behavioral plasticity.
• Plasticity in thermal tolerance and behavior is crucial for successful establishment in novel thermal environments.
• Findings support the importance of phenotypic plasticity in the success of invasive species.