Sauvard, D. | bioRxiv Science

bioRxiv2026

Flight performance of the highly invasive box tree moth Cydalima perspectalis (Lepidoptera: Crambidae)

The multivoltine non-native box tree moth, Cydalima perspectalis (Lepidoptera: Crambidae), was accidentally introduced in several continents and exhibited a very rapid expansion in its invaded ranges, colonising around 40 countries in less than twenty years. Initially observed in urban areas, it quickly spread to forest stands, causing significant damage to boxwood trees. If the role of the ornamental plant trade in its fast invasion has been investigated, the insects flight capabilities has thus far been overlooked, limiting estimations of its natural dispersal. In this context, we assessed the flight performance of the adults and investigated potential effects of sex, age and generation using computer-monitored flight mills. Under these controled conditions, we estimated the distance flown per night and over the adults lifespan in both sexes for each generation. The adults were able to fly on average 18 km within their lifespan, even though distances flown were highly variable, including several females capable of performing long-distance flights (up to 150 km). The distances covered were partly correlated with the age and body mass of the adults. Mated females flew longer distances than virgin ones, but long dispersal seemed to limit their fecundity. Finally, the overwintering generation presented the highest flight capabilities with individuals able to cover 22 km on average while the late summer generation covered only 10 km. The box tree moth showed good dispersal abilities that likely played a significant role in its rapid local expansion, while human-mediated dispersal favoured its long-distance dispersal.

ecology↗

bioRxiv2024

Intra- and interspecific variations in flight performance of oak-associated Agrilinae (Coleoptera: Buprestidae) using computerised flight mills

AO_SCPLOWBSTRACTC_SCPLOWSeveral Agrilinae species (Coleoptera: Buprestidae) are secondary pests of broadleaf forests, and some of them are also major invasive pests. These thermophilous borers are expected to be favoured by climate change and the global deterioration of forest health, and ultimately expand their range and damage. Flight behaviour and performance of these insects are poorly known despite their critical role in dispersal inside and outside native ranges and their relevance for management purposes. This study aimed to assess intra- and interspecific variability in active flight of several Agrilinae species and effects of sex and mass on this variability to contribute to filling this gap. We assessed the flight performance of eleven species associated with oaks (nine Agrilus, one Coraebus and one Meliboeus) plus one Agrilus species associated with the herbaceous layer. Computer-monitored flight mills were used to measure flight parameters, including periods, durations, distances and velocity in 250 beetles. Overall, flight capacities were rather homogeneous among species, with a dominance of poor flyers and only Coraebus undatus showed outstanding performance. Beetles generally performed several short flight bouts within one trial, and only a few individuals sustained long flight. The maximal total distance covered across multiple assays until death ranged from 170 to 16 097 m depending on the species, with a median between 35 and 966 m (excluding individuals that never flew). On top of this interspecific variability, flight distances also varied greatly among individuals, but were not influenced by sex. Preflight body mass had mixed effects depending on the species, presumably related to different dispersal patterns. In our experimental conditions, most species had limited average dispersal capacities over multiple flight trials. Overall, dispersal over long distances and colonisation events probably depend mainly on a small proportion of individuals which largely exceeded the median performance.

animal behavior and cognition↗