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Isotopic fractionation with morphological change and sexual specificity in the lappet moth E uthrix potatoria
Author(s) -
Sato Nozomu,
Azuma Nobuyuki
Publication year - 2016
Publication title -
entomologia experimentalis et applicata
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.765
H-Index - 83
eISSN - 1570-7458
pISSN - 0013-8703
DOI - 10.1111/eea.12509
Subject(s) - metamorphosis , biology , larva , sexual maturity , stable isotope ratio , zoology , fractionation , pupa , ecology , chemistry , physics , organic chemistry , quantum mechanics
The δ 15 N values of adult holometabolous insects exceed those of larvae, but otherwise little information on terrestrial invertebrates has been obtained in food‐web analyses using stable isotope ratios (δ 15 N, δ 13 C). Changes in δ 13 C during metamorphosis and differences between males and females have not been examined. We collected the larvae and cocoons of E uthrix potatoria (L.) ( L epidoptera: L asiocampidae) in the field and used them to assess the species’ isotopic fractionation. Each emerged moth was divided into five body parts. We conducted stable N and C isotope analyses for each body part, as well as for cocoons and exuviae, and also compared stable isotope ratios between sexes. We confirmed δ 15 N enrichment through metamorphosis and estimated that δ 15 N enrichment is accomplished by the relative concentration of 15 N due to the excretion of copious meconium, which contains abundant 14 N. We also observed changes in δ 13 C values through metamorphosis. Both isotope values tended to change more in males than in females. The proportion of the whole‐adult weight represented by meconium was higher in males than in females, suggesting that high meconium secretion in males contributes to the sexual difference in δ 15 N. These phenomena may be common in Holometabola, which require a pupal stage. For more accurate food‐web assessments, it is important to consider stable isotope changes during different life cycles, as well as sexual differences.