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Comparison of male antennal morphology and sensilla physiology for sex pheromone olfactory sensing between sibling moth species: Ectropis grisescens and Ectropis obliqua (Geometridae)
Author(s) -
Jing Liu,
Zhaoqun Li,
Zongxiu Luo,
Xiaoming Cai,
Lei Bian,
Zhaojun Xin,
Chen Zongmao
Publication year - 2019
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.21545
Subject(s) - sensillum , biology , sex pheromone , pheromone , lepidoptera genitalia , olfactory system , botany , pest analysis , female sex , zoology , anatomy , medicine , neuroscience
Ectropis grisescens and Ectropis obliqua (Lepidoptera: Geometridae) are sibling pest species that co‐occur on tea plants. The sex pheromone components of both species contain (Z,Z,Z)‐3,6,9‐octadecatriene and (Z,Z)‐3,9‐ cis ‐6,7‐epoxy‐octadecadiene. E. obliqua has (Z,Z)‐3,9‐ cis ‐6,7‐epoxy‐nonadecadiene as an additional sex pheromone component, which ensures reproductive segregation between the two species. To ascertain the detection mechanism of olfactory organs for sex pheromone components of E. grisescens and E. obliqua , we applied scanning electron microscopy and single sensillum recording to compare antennal morphology and sensillum physiology in the two species. There was no apparent morphological difference between the antennae of the two species. Both species responded similarly to all three sex pheromone components, including, E. obliqua specific component. The distribution patterns of antennal sensilla trichodea differed between the two species. Sex pheromone olfactory sensing in these sibling species appears to be determined by the density of different types of olfactory sensing neurons. Dose‐dependent responses of sensilla trichodea type 1 to (Z,Z)‐3,9‐ cis ‐6,7‐epoxy‐octadecadiene, the most abundant component, showed an “all or none” pattern and the other two components showed sigmoidal dose‐response curves with a half threshold of 10 −4 (dilution equal to the concentration of 10 μg/μl). These results suggest that the major sex pheromone component functions as an on–off controller while secondary components function as modulators during olfactory transmission to the primary olfactory center.