Beyond wingbeats: dispersal capacity and morphophysiological determinants in Helicoverpa zea (Lepidoptera: Noctuidae)

Abstract

Abstract Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) is a polyphagous pest impacting numerous economic crops. This impact is facilitated by its long-range dispersal capacity, which can lead to the colonization of new cultivated areas in the agricultural landscape and the potential spread of insecticide-resistant populations. Despite these negative implications, it is unclear how ecological and morphological factors influence H. zea flight capacity. Here, we investigated the dispersal capacity and morphophysiological determinants of the flight performance of H. zea. Tethered flight mill experiments were conducted to examine the impact of mating status, age [young (2-day-old), middle-aged (3- to 6-day-old), or old (7- to 9-day-old)], and sex on the flight capacity of moths under controlled conditions. We found that the flight capacity was not influenced by mating status or the number of mature eggs. Males flew faster than females, and middle-aged moths’ flight had higher performance (speed, time, and distance) than young and old moths. Body size and wing-to-thorax ratio negatively influenced the moth flight time. Male’s body size was larger than females, but they had a smaller forewing area and smaller wing-to-thorax ratio. Middle-aged moths exhibited the highest likelihood of engaging in migratory movements (> 10 km). Finally, oogenesis-flight syndrome was not detected, confirming the hypothesis of facultative migration in this species. Our results enhance our understanding of the factors influencing the flight behavior of H. zea, which can be used to predict the long-range capacity of infestation of this species, and the spread of resistance genes to management tools, such as insecticides and Bacillus thuringiensis (Bt) toxins expressed in transgenic crops.