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You are here: Home / Associated publications / Belgian Journal of Zoology / Bibliographic References / Dwarf spiders (Erigoninae, Linyphiidae, Araneae): good candidates for evolutionary research

D Vanacker, J Vanden Borre, A Jonckheere, L Maes, S Pardo, F Hendrickx, and JP Maelfait (2003)

Dwarf spiders (Erigoninae, Linyphiidae, Araneae): good candidates for evolutionary research


Males of numerous erigonine dwarf spider species, including those in the genera Oedothorax and Diplocephalus, are characterised by elaborate structures on the head region. Three evolutionary hypotheses for these head structures are : lock-and-key (reproductive isolation) hypothesis, ``conflict of interest hypothesis'' and diverse sexual selection hypotheses. Oedothorax gibbosus (Blackwall, 184 1) is a dwarf spider characterised by male dimorphism; the gibbosus morph has a hunch on the last third of the carapace, anterior to which is a hairy groove; the tuberosus morph does not have these features. During the so-called gustatorial courtship the female inserts her chelicerae into the hairy groove of gibbosus. Species recognition experiments reveal the occurrence of interspecific homo- and heterosexual ``gustatorial courtships'' of the female as well as the male of the closely related species Oedothorax fuscus (Blackwall, 1834) towards the gibbosus male. These interspecific courtships can be interpreted as robbery of the nuptial gift located in the groove and the hunch of the gibbosus males. Gibbosus males can also rob the nuptial gift of each other, but this occurs only rarely. We have never observed a `gustatorial robbery' between a tuberosus male and a gibbosus male. There are also interspecific interactions between a tuberosus male and an O. fuscus female suggesting poorly developed reproductive isolation between these sister species. These interspecific courtships are in disagreement with the lock-and-key hypothesis. Indeed, according to this hypothesis the head structures of erigonine males should function as an early prevention of hybridisation. Female chelicerae and male head structures thus do not operate as key and lock. Therefore, the head structures might have evolved under the influence of sexual selection.

Araneae; Erigoninae; speciation hypotheses; head structures; interspecific courtships; nuptial feeding
  • ISSN: 0777-6276

ISSN 2295-0451 (online version)
ISSN 0777-6279 (printed version)
impact factor 2015: 0,87.

Prof. Dr. Isa Schön
Royal Belgian Institute of Natural Sciences
Vautierstraat 29
1000 Brussels, Belgium


Annales de la Société malacologique de Belgique
​Annales de la Société royale malacologique et zoologique de Belgique
Annales de la Société Royale Zoologique de Belgique
Belgian Journal of Zoology