Observations of oviposition patterns adopted by uniparental lines of the solitary parthenogenetic endoparasitoid Venturia canescens Gravenhorst (Hymenoptera: Ichneumonidae) reveal that the occurrence of superparasitism is influenced by the genealogical relationship between adult wasps and conspecific progeny which they encounter within parasitized hosts (larvae of the Indian meal moth Plodia interpunctella Hübner (Lepidoptera: Pyralidae)): the closer the relationship, the lower the occurrence of superparasitism. This behaviour has an adaptive interpretation because it allows Venturia to avoid selective penalties incurred when larval offspring compete with genetically similar progeny. Venturia's ability to discriminate between her own eggs, those of her relatives, and those of other conspecifics is mediated by a chemical marker produced by Dufour's gland, an accessory of the adult female's reproductive system. This conclusion is supported by chemical analyses which reveal that, while Dufour's glands from unrelated females show highly significant variation between the spectra of volatile hydrocarbons contained in their respective secretions, closely‐related females show negligible differences in their chemical constitutions. These findings lend further weight to current theory that superparasitism can be deliberately deployed as an adaptive part of a wasp's behavioural repertoire, and also identify the physiological mechanism by which such an oviposition response may be achieved.
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Marris et al. (1996) studied this question.