The tethered flight technique as a tool for studying life‐history strategies associated with migration in insects

Abstract

1. Every year billions of insects engage in long‐distance, seasonal mass migrations which have major consequences for agriculture, ecosystem services and insect‐vectored diseases. Tracking this movement in the field is difficult, with mass migrations often occurring at high altitudes and over large spatial scales.2. As such, tethered flight provides a valuable tool for studying the flight behaviour of insects, giving insights into flight propensity (e.g. distance, duration and velocity) and orientation under controlled laboratory settings. By experimentally manipulating a variety of environmental and physiological traits, numerous studies have used this technology to study the flight behaviour of migratory insects ranging in size from aphids to butterflies. Advances in functional genomics promise to extend this to the identification of genetic factors associated with flight. Tethered flight techniques have been used to study migratory flight characteristics in insects for more than 50 years, but have never been reviewed.3. This study summarises the key findings of this technology, which has been employed in studies of species from six Orders. By providing detailed descriptions of the tethered flight systems, the present study also aims to further the understanding of how tethered flight studies support field observations, the situations under which the technology is useful and how it might be used in future studies.4. The aim is to contextualise the available tethered flight studies within the broader knowledge of insect migration and to describe the significant contribution these systems have made to the literature.

High risk of the fall armyworm invading Japan and the Korean Peninsula via overseas migration

“…Based on biological characteristics of the migration of S. frugiperda, trajectories were calculated with the following parameters. (i) S. frugiperda flies downwind at high altitude (Wolf, Westbrook, Raulston, & Lingren, 1995;Nagoshi, Meagher, & Fleischer, 2009), without considering a directional deflection angle (Li et al, 2019) trajectory modelling, and this speed is similar to that of other similar-sized noctuid moths (Westbrook, 2007;Li et al, 2019;Minter et al, 2018). (iii) The noctuid insects fly at night, taking off at dusk and landing at dawn on the next day (Qi, Lv, Lan, Xie, and Zhang, 2013;Wang et al, 2017).…”

Quantifying flight aptitude variation in wildA. gambiaes.l. in order to identify long-distance migrants

“…Although an ultimate 'comprehensive flight index' and cutoff values to distinguish between long-distance migrants and appetitive flyers have yet to be found, ad hoc indices and values have been successfully used (e.g. Jones et al 2016;Minter et al 2018). Flight mill-based studies to identify long-distance migrant insects often relied on total flight, longest flight and the number of flight bouts, and computed indices derived from those (Jones et al 2016;Minter et al 2018;Naranjo 2019).…”

“…2). Following previous flight behavior studies (Dingle and Arora, 1973;Taylor et al 1992;Reynolds and Frye, 2007;Lee and Leskey, 2015;Jones et al 2016;Minter et al 2018), the mosquitoes at the far-right end of the tail were suspected to represent long-distance flyers, or…”

“…Addressing such questions using aerial sampling would be challenging for many insect species because they will be intercepted at a frequency of less than one per sampling night. Tethered-flight mills (Minter et al 2018) have been used effectively to characterize short-and long-distance flyers in many species (e.g. cotton strainers (Dysdercus fasciatus, Pyrrhocoridae) (Dingle and Arora 1973), corn leafhoppers (Dalbulus maidis, Cicadellidae) (Taylor et al 1992), the brown marmorated stinkbug (Halyomorpha halys, Pentatomidae) (Lee and Leskey 2015) and Buprestid beetles (Taylor et al 2010), facilitating investigations to address questions such as those mentioned above.…”

“…However, despite their intuitive appeal, flight mill results have also been reported to be at odds with expectations in species with well-established migration (Colvin and Gatehouse 1993;Jones et al 2016;. Thus, the approach has its value and pitfalls (Taylor et al 2010;Minter et al 2018;Naranjo 2019) and predicting when it would be useful is not always clear.…”