Dispersal propensity, but not flight performance, explains variation in dispersal ability

Area of Science:

• Ecology
• Evolutionary Biology
• Entomology

Background:

• Dispersal is crucial for species range expansion and genetic structure.
• Traits differentiating dispersing from resident invertebrates are often unknown, especially in non-polymorphic species.
• Understanding these traits is vital for managing invasive species like Ceratitis capitata.

Purpose of the Study:

• To identify phenotypic traits associated with dispersal in the invasive fruit fly, Ceratitis capitata.
• To investigate the relationship between morphological traits and flight performance in dispersing insects.
• To understand how individual variation in dispersal influences insect population dynamics.

Main Methods:

• Mark-release-recapture (MRR) experiments were conducted on Ceratitis capitata.
• Comprehensive morphometric assessments were performed on captured individuals.
• Minimal adequate modeling and information theoretic approaches identified key predictors of dispersal.
• Flight ability was tested under controlled laboratory conditions.

Main Results:

• A higher thorax mass to body mass ratio was identified as a key predictor of dispersal-prone flies.
• This ratio correlated with increased mean flight duration, particularly in males.
• Increased voluntary flight activity (number and duration) was also associated with a larger thorax mass to body mass ratio.
• No significant differences were found in other whole-animal flight performance metrics.

Conclusions:

• The thorax mass to body mass ratio is a significant predictor of dispersal propensity in Ceratitis capitata.
• Enhanced voluntary flight behavior, influenced by this ratio, can significantly alter insect movement patterns.
• This finding helps explain variation in insect dispersal ability and its ecological consequences.