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Defensive secretions of larvae of a carabid beetle
Author(s) -
Holliday Alison E.,
Mattingly Travis M.,
Holliday Neil J.
Publication year - 2015
Publication title -
physiological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 57
eISSN - 1365-3032
pISSN - 0307-6962
DOI - 10.1111/phen.12096
Subject(s) - hydroquinone , biology , larva , benzoquinone , gas chromatography–mass spectrometry , mass spectrometry , zoology , gas chromatography , botany , chromatography , biochemistry , chemistry
Secretions of an eversible gland on the metathorax of larvae of Chlaenius cordicollis K irby ( C oleoptera: C arabidae) are investigated by headspace analysis using solid phase microextraction followed by gas chromatography‐mass spectrometry ( GC‐MS ). Larvae from M anitoba, C anada and P ennsylvania, U.S.A ., are sampled. Nine presumed defensive compounds are detected when the gland is everted, and this represents the first characterization of defensive secretions of larvae of a carabid beetle. With the exception of a single component (2‐methoxy‐4‐methylphenol), these compounds are distinct from those found in the defensive secretion of adult C. cordicollis . However, seven are more oxidized versions of the alkylphenolic compounds secreted by adult beetles: three hydroquinones (hydroquinone, methylhydroquinone and 2,3‐dimethylhydroquinone) and four quinones ( p ‐benzoquinone, toluquinone, 2,3‐dimethylquinone and ethyl‐ p ‐benzoquinone). An additional alkoxyphenol (2‐methoxy‐4‐ethylphenol) is also detected. Two patterns of composition are observed: in one, p ‐benzoquinone and hydroquinone are undetectable and the ratio of toluquinone : 2,3‐dimethylquinone is 1 : 4.6 ± 0.6 (mean ± SE ); in the other, all nine compounds are detectable and the ratio of toluquinone : 2,3‐dimethylquinone is 1 : 1.0 ± 0.2. These differences in pattern do not appear to be related to geographical source, sex or age of the larvae.