Artificial selection for enhanced flight propensity in an invasive species (Ceratitis capitata) reveals minimal...

Enhanced flight propensity may facilitate range expansions with implications for evolutionary potential, population dynamics, and species invasions. This study investigated artificial selection for flight propensity in a highly invasive agricultural fruit pest, the Mediterranean fruit fly (Medfly), Ceratitis capitata under laboratory conditions. A selection filter was applied for 4-5 generations of C. capitata to select for the fastest (and as a reference group the most lethargic) flyers. Individuals that were able to rapidly overcome a flight barrier were termed "Flyers", while philopatric individuals were referred to as "Non-flyers." Flight propensity was quantified using flight performance measurements, whereas walking speed was used as a measurement of locomotor activity. Reproductive traits, thermal performance (i.e., chill coma recovery and heat knockdown time), and desiccation and starvation resistance were assessed for potential physiological trade-offs that may be associated with increased flight propensity. Flight performance trials showed that Flyers performed significantly better than Non-flyers after 4-5 generations of selection, with only female Flyers showing an increased body mass compared to Non-flyers. Cold stress-resistance was the only trait where Non-flyers outperformed Flyers, while thermal tolerance and fecundity traits remained similar between Flyers and Non-flyers. These findings demonstrated that it may be possible to select for enhanced flight propensity without incurring substantial performance or life-history costs. The ability to improve flight performance with minimal costs could be a key factor contributing to the success of invasive species, such as the Mediterranean fruit fly.