Flight altitude selection increases orientation performance in high-flying nocturnal insect migrants
Aralimara, Prabhuraj, Reynolds, Andy M., Lim, Ka S., Reynolds, Don R. and Chapman, Jason W. (2011) Flight altitude selection increases orientation performance in high-flying nocturnal insect migrants. Animal Behaviour, 82. pp. 1221-1225. ISSN 0003-3472 (online) (doi:10.1016/j.anbehav.2011.09.013)Full text not available from this repository.
Many insects migrate at high altitudes where they utilize fast-ﬂowing airstreams for long-distance transport. Nocturnal insect migrants typically exhibit a strongly unimodal distribution of ﬂight headings (a phenomenon termed ‘common orientation’), and the mean heading is often aligned downwind. In addition, these nocturnal migrants are sometimes concentrated into shallow altitudinal zones (termed ‘layers’). The mechanism by which widely separated insects select and maintain common ﬂight headings had until recently eluded explanation, but recent theoretical advances have shown that atmospheric turbulence might enable insects to perceive the downwind direction and orient accordingly. This theory predicts that common orientation downwind should be: (1) widespread in nocturnal insect migrants; (2) facilitated when insects are concentrated into layers; and (3) more pronounced in larger insects. We tested these ideas using radar observations of 647 independent nocturnal migration events, and found strong support for all three predictions: (1) common orientation occurred in 75e90% of events; (2) common orientation was more frequent, had signiﬁcantly less scatter and was signiﬁcantly closer to downwind when insects migrated in layers; and (3) large insects exhibited signiﬁcantly tighter orientation than ‘medium-sized’ insects. Our results provide robust evidence that wind-related common orientation is mediated by detection of atmospheric turbulence.
|Uncontrolled Keywords:||entomological radar, ﬂight altitude, insect layer, migration, orientation cue, turbulence|
|Subjects:||S Agriculture > S Agriculture (General)|
|School / Department / Research Groups:||Natural Resources Institute|
Natural Resources Institute > Agriculture, Health & Environment
|Last Modified:||10 Feb 2012 09:24|
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