Limited Variability of Genitalia in the Genus Pimpla (Hymenoptera: Ichneumonidae): Inter- or Intraspecific Causes?

Author: Teder, TT

Source: Netherlands Journal of Zoology, Volume 48, Number 4, 1998 , pp. 335-347(13)

Publisher: BRILL

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Abstract:

We studied the morphometric variability of genitalia in five species of the genus Pimpla (Hymenoptera, Ichneumonidae). This genus is characterized by a high intraspecific variation in body size, a simple structure of the genitalia and many closely related species. We found that genitalic characters of all studied species vary less than characters related to body size. However, there exists an overlap in genitalic characters between different species. The pattern of variance and the ecology of the species studied suggests that low variance of genitalia cannot be explained by interspecific causes (mechanical isolation) or sperm competition. The most likely explanation for the low variance of genitalia is assuring mechanical fit between male and female during copulation. Sexual selection by female choice may be a cause of the observed pattern of variance as well, if females have active preference for males with larger genitalia. We suggest that genitalia of insects with a large variation in body size vary less than other morphological characters to ensure intraspecific mechanical fit.

Keywords: genitalia; body size; morphometry; Ichneumonidae; Pimpla

Document Type: Research article

DOI: http://dx.doi.org/10.1163/156854298X00039

Affiliations: 1: Institute of Zoology and Botany, Estonian Agricultural University, Riia 181, EE2400 Tartu, Estonia, Institute of Zoology and Hydrobiology, Tartu University, EE2400 Tartu, Estonia

Publication date: 1998-01-01

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