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Solitary and Gregarious Locusts Differ in Circadian Rhythmicity of a Visual Output Neuron

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journal contribution
posted on 26.06.2012, 12:18 by Edward Gaten, Stephen J. Huston, Harold B. Dowse, Tom Matheson
Locusts demonstrate remarkable phenotypic plasticity driven by changes in population density. This density dependent phase polyphenism is associated with many physiological, behavioral, and morphological changes, including observations that cryptic solitarious (solitary-reared) individuals start to fly at dusk, whereas gregarious (crowd-reared) individuals are day-active. We have recorded for 24-36 h, from an identified visual output neuron, the descending contralateral movement detector (DCMD) of Schistocerca gregaria in solitarious and gregarious animals. DCMD signals impending collision and participates in flight avoidance maneuvers. The strength of DCMD's response to looming stimuli, characterized by the number of evoked spikes and peak firing rate, varies approximately sinusoidally with a period close to 24 h under constant light in solitarious locusts. In gregarious individuals the 24-h pattern is more complex, being modified by secondary ultradian rhythms. DCMD's strongest responses occur around expected dusk in solitarious locusts but up to 6 h earlier in gregarious locusts, matching the times of day at which locusts of each type are most active. We thus demonstrate a neuronal correlate of a temporal shift in behavior that is observed in gregarious locusts. Our ability to alter the nature of a circadian rhythm by manipulating the rearing density of locusts under identical light-dark cycles may provide important tools to investigate further the mechanisms underlying diurnal rhythmicity.

History

Citation

Journal of Biological Rhythms, 2012, 27 (3), pp. 196-205

Author affiliation

/Organisation/COLLEGE OF MEDICINE, BIOLOGICAL SCIENCES AND PSYCHOLOGY/School of Biological Sciences/Department of Biology

Version

AM (Accepted Manuscript)

Published in

Journal of Biological Rhythms

Publisher

Sage Publications

issn

0748-7304

eissn

1552-4531

Copyright date

2012

Available date

30/06/2013

Publisher version

http://jbr.sagepub.com/content/27/3/196

Language

en

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