Behavioral Ecology and Sociobiology

, Volume 67, Issue 11, pp 1719–1730

Same-sex sexual behavior in insects and arachnids: prevalence, causes, and consequences


DOI: 10.1007/s00265-013-1610-x

Cite this article as:
Scharf, I. & Martin, O.Y. Behav Ecol Sociobiol (2013) 67: 1719. doi:10.1007/s00265-013-1610-x


Same-sex sexual (SSS) behavior represents an evolutionary puzzle: whilst associated costs seem obvious, positive contributions to fitness remain unclear. Various adaptive explanations have been proposed and thorough reviews exist for vertebrates, but a thorough synthesis of causes for SSS behavior in invertebrates is lacking. Here we provide evidence for such behavior in ~110 species of insects and arachnids. Males are more frequently involved in SSS behavior in the laboratory than in the field, and isolation, high density, and exposure to female pheromones increase its prevalence. SSS behavior is often shorter than the equivalent heterosexual behavior. Most cases can be explained via mistaken identification by the active (courting/mounting) male. Adaptive explanations, such as sperm transfer of the mounting male via the mounted one or gaining experience by young males, are of limited general significance. The passive (being courted/mounted) male is sometimes responsible for this “mistake” by releasing sex pheromones or carrying female pheromones that were attached to his cuticle during prior mating activity. Passive males often resist courting/mating attempts. SSS behavior in arthropods is predominantly based on mistaken identification and is probably maintained because the cost of rejecting a valid opportunity to mate with a female is greater than that of mistakenly mating with a male. Many species exhibiting SSS behavior also mate with related species, another case of mistaken identification. Future research should focus on uncovering the situations/contexts in which mistaken identification is more or less costly for males.


Homosexual Intra-sexual Reproductive interference Male–male Mating costs 

Supplementary material

265_2013_1610_MOESM1_ESM.xls (120 kb)
ESM 1(XLS 119 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  1. 1.Department of Zoology, Faculty of Life SciencesTel Aviv UniversityTel AvivIsrael
  2. 2.Experimental Ecology, Institute of Integrative Biology IBZETH ZurichZurichSwitzerland

Personalised recommendations