Orientation in high-flying migrant insects in relation to flows: mechanisms and strategies

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.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'.Rothamsted Research is a national institute of bioscience strategically funded by the UK Biotechnology and Biological Sciences Research Council (BBSRC). The visiting scholarship of G.H. at Rothamsted was funded by Nanjing Agricultural University and the Priority Academic Programme Development of Jiangsu Higher Education Institutions. S.P.S. acknowledges the Ramanujan Fellowship from the Department of Science and Technology, India