Distinct Behavioral Patterns Across a Non-Native Population of Gambusia affinis

Area of Science:

• Ecology
• Evolutionary Biology
• Behavioral Ecology

Background:

• Invasive species often exhibit phenotypic differences at range boundaries compared to established populations.
• Understanding the extent and drivers of such variation is crucial for predicting invasion success.
• The western mosquitofish (Gambusia affinis) is a widespread invasive species suitable for studying range expansion dynamics.

Purpose of the Study:

• To investigate behavioral variation in western mosquitofish subpopulations established for different durations.
• To determine if exploratory behavior, boldness, activity level, and sociality differ among these subpopulations.
• To assess correlations between these behaviors and whether variation in correlated behaviors differs by establishment time.

Main Methods:

• Fish were collected from three western mosquitofish subpopulations in the Susquehanna River watershed, differing in estimated establishment time.
• Collected fish were subjected to a series of behavioral tests.
• Behaviors analyzed included exploratory behavior, boldness, activity level, and sociality.

Main Results:

• Fish from the longest-established subpopulation exhibited significantly higher activity levels compared to those from more recently established subpopulations.
• High boldness, activity levels, and sociality were found to be correlated across all studied subpopulations.
• No significant differences were found in the variation of these correlated behaviors based on the estimated time since subpopulation establishment.

Conclusions:

• While western mosquitofish subpopulations show some behavioral divergence (activity levels) related to establishment time, this variation is not uniform across all studied behaviors.
• The correlated suite of boldness, activity, and sociality did not exhibit differential variation based on establishment duration in this study.
• Further research is needed to fully understand the role of phenotypic variation in facilitating the success of invasive species.