Body size, host choice and sex allocation in a spider-hunting pompilid wasp

István Karsai, Kálmán Somogyi, Ian C.W. Hardy

Research output: Contribution to journalArticle

13 Citations (Scopus)


Two important relationships in parasitoid evolutionary ecology are those between adult size and fitness and between host quality and sex ratio. Sexually differential size-fitness relationships underlie predicted sex-ratio relationships. Despite each relationship receiving considerable attention, they have seldom been studied simultaneously or using field data. Here we report the biology of Anoplius viaticus paganus Dahlbom, a little known parasitoid of spiders, using field and laboratory data. We found that larger foraging females were able to select larger host spiders from the field, thus identifying a relatively novel component of the size-fitness relationship. Larger offspring developed from larger hosts and, in agreement with the prediction of the host quality model of sex allocation, were generally female. Data on the size-fitness relationship for males are lacking and, in common with many prior studies, we could not evaluate sexually differential size-fitness relationships as an explanation for the observed sex-ratio patterns. Nonetheless, A. v. paganus exhibited one of the strongest relationships between host size and offspring sex ratio yet reported.

Original languageEnglish
Pages (from-to)285-296
Number of pages12
JournalBiological Journal of the Linnean Society
Issue number2
Publication statusPublished - Feb 1 2006



  • Anoplius
  • Field data
  • Host size
  • Sex ratio
  • Size-fitness relationship

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

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