Floral to green: mating switches moth olfactory coding and preference.
Mating induces profound physiological changes in a wide range of insects, leading to behavioural adjustments to match the internal state of the animal. Here, we show for the first time, to our knowledge, that a noctuid moth switches its olfactory response from food to egg-laying cues following mating. Unmated females of the cotton leafworm (Spodoptera littoralis) are strongly attracted to lilac flowers (Syringa vulgaris). After mating, attraction to floral odour is abolished and the females fly instead to green-leaf odour of the larval host plant cotton, Gossypium hirsutum. This behavioural switch is owing to a marked change in the olfactory representation of floral and green odours in the primary olfactory centre, the antennal lobe (AL). Calcium imaging, using authentic and synthetic odours, shows that the ensemble of AL glomeruli dedicated to either lilac or cotton odour is selectively up- and downregulated in response to mating. A clear-cut behavioural modulation as a function of mating is a useful substrate for studies of the neural mechanisms underlying behavioural decisions. Modulation of odour-driven behaviour through concerted regulation of odour maps contributes to our understanding of state-dependent choice and host shifts in insect herbivores.
Chemical Ecology Group, Swedish University of Agricultural Sciences, 230 53 Alnarp, Sweden.
Ahmed M
AM
Saveer
Sophie H
SH
Kromann
Göran
G
Birgersson
Marie
M
Bengtsson
Tobias
T
Lindblom
Anna
A
Balkenius
Bill S
BS
Hansson
Peter
P
Witzgall
Paul G
PG
Becher
Rickard
R
Ignell
D000704:Analysis of Variance; D000818:Animals; D001070:Appetitive Behavior / Q000502:physiology; D001931:Brain Mapping; D003463:Cues; D005260:Female; D035264:Flowers / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D003368:Gossypium / Q000737:chemistry; D007091:Image Processing, Computer-Assisted; D009036:Moths / Q000502:physiology*; D009812:Odorants; D018515:Plant Leaves / Q000737:chemistry; D012726:Sexual Behavior, Animal / Q000502:physiology*; D012903:Smell / Q000502:physiology*; D013548:Sweden; D031662:Syringa / Q000737:chemistry