The transition to social inbred mating systems in spiders: Role of inbreeding tolerance in a subsocial predecessor

Trine Bilde, Yael Lubin, Deborah Smith, Jutta M. Schneider, Alexei A. Maklakov

    Research output: Contribution to journalArticlepeer-review

    96 Scopus citations

    Abstract

    The social spiders are unusual among cooperatively breeding animals in being highly inbred. In contrast, most other social organisms are outbred owing to inbreeding avoidance mechanisms. The social spiders appear to originate from solitary subsocial ancestors, implying a transition from outbreeding to inbreeding mating systems. Such a transition may be constrained by inbreeding avoidance tactics or fitness loss due to inbreeding depression. We examined whether the mating system of a subsocial spider, in a genus with three social congeners, is likely to facilitate or hinder the transition to inbreeding social systems. Populations of subsocial Stegodyphus lineatus are substructured and spiders occur in patches, which may consist of kin groups. We investigated whether male mating dispersal prevents matings within kin groups in natural populations. Approximately half of the marked males that were recovered made short moves (< 5m) and mated within their natal patch. This potential for inbreeding was counterbalanced by a relatively high proportion of immigrant males. In mating experiments, we tested whether inbreeding actually results in lower offspring fitness. Two levels of inbreeding were tested: full sibling versus non-sib matings and matings of individuals within and between naturally occurring patches of spiders. Neither full siblings nor patch mates were discriminated against as mates. Sibling matings had no effect on direct fitness traits such as fecundity, hatching success, time to hatching and survival of the offspring, but negatively affected offspring growth rates and adult body size of both males and females. Neither direct nor indirect fitness measures differed significantly between within patch and between-patch pairs. We tested the relatedness between patch mates and nonpatch mates using DNA fingerprinting (TE-AFLP). Kinship explained 30% of the genetic variation among patches, confirming that patches are often composed of kin. Overall, we found limited male dispersal, lack of kin discrimination, and tolerance to low levels of inbreeding. These results suggest a history of inbreeding which may reduce the frequency of deleterious recessive alleles in the population and promote the evolution of inbreeding tolerance. It is likely that the lack of inbreeding avoidance in subsocial predecessors has facilitated the transition to regular inbreeding social systems.

    Original languageEnglish
    Pages (from-to)160-174
    Number of pages15
    JournalEvolution
    Volume59
    Issue number1
    DOIs
    StatePublished - 1 Jan 2005

    Keywords

    • DNA fingerprinting
    • Inbreeding avoidance
    • Inbreeding rate
    • Inbreeding tolerance
    • Kin-structured population
    • Life-history traits
    • Sibling mating; sex-specific dispersal

    ASJC Scopus subject areas

    • Ecology, Evolution, Behavior and Systematics
    • Genetics
    • General Agricultural and Biological Sciences

    Fingerprint

    Dive into the research topics of 'The transition to social inbred mating systems in spiders: Role of inbreeding tolerance in a subsocial predecessor'. Together they form a unique fingerprint.

    Cite this