Clever birds are lousy: Co-variation between avian innovation and the taxonomic richness of their amblyceran lice

Zoltán Vas, Louis Lefebvre, Kevin P. Johnson, Jeno Reiczigel, Lajos Rózsa

Research output: Contribution to journalArticlepeer-review


Lice (Insecta: Phthiraptera) are ectoparasites that reduce host life expectancy and sexual attractiveness. Their taxonomic richness varies considerably among their hosts. Previous studies have already explored some important factors shaping louse diversity. An unexplored potential correlate of louse taxonomic richness is host behavioural flexibility. In this comparative study, we examine the relationship between louse generic richness, innovative capabilities (as a proxy for behavioural flexibility), and brain size while controlling for host species diversity, phylogeny, body size and research effort. Using data for 108 avian families, we found a highly significant positive relationship between host innovative capabilities and the taxonomic richness of amblyceran lice, but a lack of a similar relationship in ischnoceran lice. Host brain size had only a marginal impact on amblyceran diversity and no correlation with ischnoceran diversity. This suggests that the effect in Amblycera is not mediated by metabolic limitations due to the energetic costs of brain size and maintenance, rather directly caused by the ecological differences between hosts with differing cognitive capabilities. We propose four alternative and mutually non-exclusive hypotheses that may explain this phenomenon.

Original languageEnglish (US)
Pages (from-to)1295-1300
Number of pages6
JournalInternational Journal for Parasitology
Issue number12
StatePublished - Oct 2011


  • Behavioural flexibility
  • Brain size
  • Ectoparasite
  • Host-parasite evolution
  • Independent contrast
  • Lice

ASJC Scopus subject areas

  • Parasitology
  • Infectious Diseases


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