The sexually dimorphic behaviour of adult Drosophila suzukii: elevated female locomotor activity and loss of siesta is a post-mating response.
The polyphagous Drosophila suzukii is a highly invasive species that causes extensive damage to a wide range of berry and stone fruit crops. A better understanding of its biology and especially its behaviour will aid the development of new control strategies. We investigated the locomotor behaviour of D. suzukii in a semi-natural environment resembling a typical summer in northern England and show that adult female D. suzukii are at least 4-fold more active during daylight hours than adult males. This result was reproduced in several laboratory environments and was shown to be a robust feature of mated, but not virgin, female flies. Both males and virgin females kept on a 12 h light:12 h dark (12LD) cycle and constant temperature displayed night-time inactivity (sleep) followed by weak activity in the morning, an afternoon period of quiescence (siesta) and then a prominent evening peak of activity. Both the siesta and the sharp evening peak at lights off were severely reduced in females after mating. Flies of either sex entrained in 12LD displayed a circadian pattern of activity in constant darkness confirming the importance of an endogenous clock in regulating adult activity. This response of females to mating is similar to that elicited in female Drosophila melanogaster by the male sex peptide (SP). We used mass spectrometry to identify a molecular ion (m/z, 5145) corresponding to the poly-hydroxylated SP of D. suzukii and to show that this molecule is transferred to the female reproductive tract during copulation. We propose that the siesta experienced by male and virgin female D. suzukii is an adaptation to avoid unnecessary exposure to the afternoon sun, but that mated females faced with the challenge of obtaining resources for egg production and finding oviposition sites take greater risks, and we suggest that the change in female behaviour is induced by the male SP.
School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK Institute of Particle Science and Engineering, School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, UK.
Calum T J
CT
Ferguson
School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
Tara L
TL
O'Neill
The Food and Environmental Research Agency, Sand Hutton, York YO41 1LZ, UK.
Neil
N
Audsley
School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK r.e.isaac@leeds.ac.uk.
R Elwyn
RE
Isaac
D000818:Animals; D002940:Circadian Rhythm; D003307:Copulation / Q000502:physiology; D003624:Darkness; D004330:Drosophila / Q000502:physiology*; D029721:Drosophila Proteins / Q000032:analysis; D005260:Female; D008124:Locomotion; D008297:Male; D010455:Peptides / Q000032:analysis; D012727:Sex Characteristics; D012890:Sleep / Q000502:physiology
D029721:Drosophila Proteins; D010455:Peptides
Circadian rhythm; Fruit fly; Pest management; Sex peptide; Sleep