Insects are the most diverse and abundant group of terrestrial migrants often involving the movement of billions to trillions of individuals in a single season. Insects play a critical role in ecosystems worldwide, both as ecosystem service providers (e.g. pollination and biocontrol), as well as causing detrimental effects (e.g. huge invasions of migratory pest species, such as locusts). Insect migration also involves the immense movement of biomass, resulting in significant nutrient transport between habitats. However, despite their significant role in ecosystems, the migratory pathways and mechanisms behind large-scale population connectivity of insects, is poorly understood. Migration involves movement across large spatial scales, which can pose challenges for studying this phenomenon, particularly when tracking small migratory animals, such as insects. Therefore, remote sensing methods such as radar combined with remote technology that can be carried by the animals themselves, can prove particularly useful for studying this fascinating phenomenon.
This will be the first study of its kind to combine the state-of-the-art methods of individual insect tracking (using radio-telemetry) and radar methods to record migratory behaviour and direction, while also investigating departure decisions along the migratory route. Therefore, results from the proposed research will have wide-ranging impacts for understanding the mechanisms behind insect migrations and the movement patterns of both species of conservation concern and pest species, and facilitate effective management actions. Understanding insect movements and landscape use will also have significant implications for identifying the mechanisms that contribute to the observed patterns of insect population decline.
Using a unique combination of individual tracking, vertical-looking radar and trapping data, we investigated the migratory behaviour of hawkmoths to provide insight into migratory routes and departure decisions. In this project, we aimed to investigate two main sets of objectives, which provide the basis for three work packages:
Objective 1 (Work Package 1): Our objective was to investigate the influence of radio-transmitters on the flight behaviour of hawkmoths in the field and the laboratory. Secondly, we investigated the movement behaviour of hawkmoths to gain important baseline information on flight behaviour, movements and home range size.
Objective 2 (Work Packages 2 and 3): Our objectives were to elucidate the migratory pathways of hawkmoths, to understand migratory flight and orientation behaviour in relation to topography and weather conditions along these routes. Furthermore, we aimed to investigate which factors influence individual departure decisions and stopovers en route.
