Oviposition site-selection by Bactrocera dorsalis is mediated through an innate recognition template tuned to γ-octalactone.
Innate recognition templates (IRTs) in insects are developed through many years of evolution. Here we investigated olfactory cues mediating oviposition behavior in the oriental fruit fly, Bactrocera dorsalis, and their role in triggering an IRT for oviposition site recognition. Behavioral assays with electrophysiologically active compounds from a preferred host, mango, revealed that one of the volatiles tested, γ-octalactone, had a powerful effect in eliciting oviposition by gravid B. dorsalis females. Electrophysiological responses were obtained and flies clearly differentiated between treated and untreated substrates over a wide range of concentrations of γ-octalactone. It triggered an innate response in flies, overriding inputs from other modalities required for oviposition site evaluation. A complex blend of mango volatiles not containing γ-octalactone elicited low levels of oviposition, whereas γ-octalactone alone elicited more oviposition response. Naïve flies with different rearing histories showed similar responses to γ-octalactone. Taken together, these results indicate that oviposition site selection in B. dorsalis is mediated through an IRT tuned to γ-octalactone. Our study provides empirical data on a cue underpinning innate behavior and may also find use in control operations against this invasive horticultural pest.
National Fellow Lab, Division of Entomology and Nematology, Indian Institute of Horticultural Research, Bangalore, India.
Kamala Jayanthi
KJ
Pagadala Damodaram
National Fellow Lab, Division of Entomology and Nematology, Indian Institute of Horticultural Research, Bangalore, India.
Vivek
V
Kempraj
National Fellow Lab, Division of Entomology and Nematology, Indian Institute of Horticultural Research, Bangalore, India.
Ravindra Mahadappa
RM
Aurade
Department of Ecology, National Bureau of Agriculturally Important Insects, Bangalore, India.
Ravindra Kothapalli
RK
Venkataramanappa
National Fellow Lab, Division of Entomology and Nematology, Indian Institute of Horticultural Research, Bangalore, India.
Bakthavatsalam
B
Nandagopal
Department of Ecology, National Bureau of Agriculturally Important Insects, Bangalore, India.
Abraham
A
Verghese
Biological Chemistry and Crop Protection, Rothamsted Research, West Common, Harpenden, United Kingdom.
Toby
T
Bruce
D000818:Animals; D001522:Behavior, Animal; D002630:Chemotactic Factors / Q000494:pharmacology / Q000502:physiology*; D005260:Female; D007783:Lactones / Q000378:metabolism* / Q000494:pharmacology; D055696:Olfactory Perception; D010058:Oviposition / Q000187:drug effects*; D010571:Pest Control; D033621:Tephritidae / Q000502:physiology*
D002630:Chemotactic Factors; D007783:Lactones