Chemical sex recognition in the harvestman Discocyrtus prospicuus (Arachnida: Opiliones)

Author(s)

Fernandes, Nathalia S. ; Stanley, Estefania ; Costa, Fernando G. ; Toscano-Gadea, Carlos A. ; Willemart, Rodrigo H.

• Document type: Journal article
• Source: ACTA ETHOLOGICA; v. 20, n. 3, p. 215-221, OCT 2017.
• Web of Science Citations: 1

Abstract

Several arachnid species use chemicals to detect sexual partners. In harvestmen, there are evidences that chemicals may play a role in intraspecific communication. Using the behavior of Discocyrtus prospicuus (Holmberg 1876), whose males expose the penis to females before they engage in mating posture, we tested if males detect females by contact chemoreception (chemicals left on the substrate) and if males detect females by olfaction. First, we exposed males to three experimental groups, where males had to choose between two substrates: female chemicals/blank control; male chemicals/blank control; female/male chemicals. Then, we gave males access to volatiles of males, females, and control simultaneously. We predicted that males would expose the penis when approaching volatiles and chemicals deposited on the substrate by females. We also tested if males spent more time close to the source of female volatiles and on the substrate with female chemicals and if males tapped the substrate with female chemicals for more time than the others. Finally, we put males and females together to observe if males would expose the penis upon touching the female's cuticle. Most of our predictions were not supported, though males did tap for more time when exposed to female cues instead of male cues and exposed the penis in 70% of the observations when interacting with the female but only after touching her. Our data does not support olfaction as a way to detect females and corroborate the idea that contact chemicals, either on the substrate or on female's cuticle, play an important role in the detection and recognition of the opposite sex. This is the first evidence in harvestmen that males may react differently to female/male chemicals. (AU)

• FAPESP's process: 10/00915-0 - Chemical communication in harvestmen (Arachnida, Opiliones): morphology, behavior and chemistry
• Grantee: Rodrigo Hirata Willemart
• Support Opportunities: Research Grants - Young Investigators Grants