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Quantifying income breeding: using geometrid moths as an example
Author(s) -
Javoiš Juhan,
Molleman Freerk,
Tammaru Toomas
Publication year - 2011
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/j.1570-7458.2011.01120.x
Subject(s) - biology , lepidoptera genitalia , sexual dimorphism , ecology , larva , zoology
Although the general concept of capital vs. income breeding has become widely used in insect ecology, finding easy‐to‐measure indices for quantifying the role of larval‐ vs. adult‐derived nutrients in egg production has remained a challenge. When searching for possible candidates for this task, we evaluated the applicability of three morphometric ratios to be measured on freshly eclosed adults: (1) relative size of female abdomen, (2) sexual size dimorphism, and (3) proportion of volume of mature eggs relative to total volume of female abdomen. We report the values of these indices in five species of geometrid moths [ Hypomecis punctinalis Scopoli, Ematurga atomaria L., Selenia tetralunaria Hufnagel, Semiothisa clathrata L., and Epirrhoe alternata Müller (all Lepidoptera: Geometridae)] and compare them to the degrees of income breeding measured directly by oviposition experiments. As a comparison, we also recorded the ovigeny index and the effect of income on lifespan. All morphometric indices varied considerably between the species studied, and, as predicted, the values of all three proposed indices were higher in the more capital‐breeding species. The only exception to this pattern was a low proportion of mature eggs in abdomens in one primarily capital‐breeding species, S. tetralunaria . Unlike other capital breeders, this species also proved to be largely synovigenic, indicating that capital breeding and pro‐ovigeny are not strictly linked. The reproductive traits measured concord with ecological niches occupied by the species studied: the oligophagous meadow dwellers were largely income breeding and synovigenic, whereas the polyphagous forest dwellers were capital breeders. The high and predictable among‐species variation in egg‐production strategies suggests that geometrid moths form a promising target group for comparative studies on respective traits. Simple anatomical indices, in turn, appear to be applicable as easy‐to‐record proxies of egg production strategies.