title: Orientation in high-flying migrant insects in relation to flows: mechanisms and strategies.
abstract: High-flying insect migrants have been shown to display sophisticated flight orientations that can, for example, maximize distance travelled by exploiting tailwinds, and reduce drift from seasonally optimal directions. Here, we provide a comprehensive overview of the theoretical and empirical evidence for the mechanisms underlying the selection and maintenance of the observed flight headings, and the detection of wind direction and speed, for insects flying hundreds of metres above the ground. Different mechanisms may be used-visual perception of the apparent ground movement or mechanosensory cues maintained by intrinsic features of the wind-depending on circumstances (e.g. day or night migrations). In addition to putative turbulence-induced velocity, acceleration and temperature cues, we present a new mathematical analysis which shows that 'jerks' (the time-derivative of accelerations) can provide indicators of wind direction at altitude. The adaptive benefits of the different orientation strategies are briefly discussed, and we place these new findings for insects within a wider context by comparisons with the latest research on other flying and swimming organisms.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.
authors.affiliation: Computational and Systems Biology Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
authors.forename: Andy M
authors.initials: AM
authors.lastname: Reynolds
authors.affiliation: Natural Resources Institute, University of Greenwich, Chatham, Kent ME4 4TB, UK Department of Agroecology, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
authors.forename: Don R
authors.initials: DR
authors.lastname: Reynolds
authors.affiliation: National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560 065, Karnataka, India.
authors.forename: Sanjay P
authors.initials: SP
authors.lastname: Sane
authors.affiliation: Department of Agroecology, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK College of Plant Protection, Nanjing Agricultural University, Nanjing, People's Republic of China.
authors.forename: Gao
authors.initials: G
authors.lastname: Hu
authors.affiliation: Department of Agroecology, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall TR10 9EZ, UK Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9EZ, UK jason.chapman@rothamsted.ac.uk.
authors.forename: Jason W
authors.initials: JW
authors.lastname: Chapman
mesh_terms: D000392:Air Movements; D025041:Animal Migration; D000818:Animals; D003463:Cues; D005426:Flight, Animal; D007313:Insecta / Q000502:physiology*; D000072458:Orientation, Spatial; D014796:Visual Perception; D014919:Wind
keywords: flight orientation; flow sensing; migration strategies; optomotor responses; turbulence directionality cues