Does silk mediate chemical communication between the sexes in a nuptial feeding spider?
Chemical signals play a crucial role in reproduction as a means for locating mates and/or gaining information about their quality, ultimately affecting mating system dynamics and mate choice. In spiders, one of the potential sources of chemical signalling is silk. However, while female silk is known to attract mates and/or elicit courtship, due to sex-specific roles in mate searching, male silk-related signals are often neglected. In the hunting spider Pisaura mirabilis (Pisauridae), both sexes leave silk draglines during movements while males additionally use silk to wrap nuptial gifts (food donations to females at mating). We explored the potential for both silk types (draglines and gift silk) to release signals and tested the hypothesis that chemical compounds bound to gifts’ silk serve to elicit female attraction. We conducted behavioural choice assays for dragline and gift silk, and their putative transmission mode (airborne or contact) by testing (i) male and female attraction towards draglines of the opposite sex and (ii) female attraction towards gift silk. Whereas males were attracted to female draglines (contact cues), females did not respond to male silk of any type. We suggest that females use draglines for advertisement to secure copulation and foraging of nuptial gifts. If these signals ease male mate searching, attractive male draglines are unnecessary. Overall, males may not invest in chemical stimulation but rather exploit female foraging interests through gift giving. Alternatively, they may release signals that prime other female sexual behaviours or towards which females may have evolved resistance.
Animals commonly use chemical signals to communicate during reproduction, and spiders have the potential to release such signals from their silk. We investigated whether two silk types, draglines released during movements and silk covering male nuptial gifts (prey offered to females at mating) are attractive to the opposite sex in a hunting spider. While males were attracted to female draglines, females did not respond to male silk of any type. Females may be using silk to advertise themselves to secure matings and food through reception of nuptial gifts. If males can successfully locate females, attracting females through draglines may be unnecessary. The finding that males do not release attractant signals in the silk cover of their nuptial gifts further suggests that rather than attempting to increase their attractiveness by using chemical stimulation, males may be uniquely exploiting females’ interest in food through gift giving behaviour.
KeywordsSilk Sexual selection Chemical signals Nuptial gifts
We thank Patricia Velado Lobato for assistance in data collection and Federico Cappa for constructive contribution to the experimental design and comments on the manuscript.
CT conceived the study, MB and TC designed the experiments, MB collected the data, TC analysed the data and CT led the writing of the manuscript with all authors contributing relevantly to the draft and giving final approval for publication.
- Albo MJ, Toft S, Bilde T (2013) Sexual selection, ecology and evolution of nuptial gifts in spiders. Sex Sel Perspect Model Neotrop:183–200Google Scholar
- Arnqvist G, Rowe L (2013) Sexual conflict. Princeton University Press, PrincetonGoogle Scholar
- Bates D, Mächler M, Bolker B, Walker S (2014) Fitting linear mixed-effects models using lme4. arXiv preprint arXiv:1406.5823.Google Scholar
- Bradbury JW, Vehrencamp SL (2011) Principles of animal communication, 2nd edn. Sinauer Associates, Inc., MassachussetsGoogle Scholar
- Bristowe WS, Locket GH (1926) The courtship of British lycosid spiders, and its probable significance. Proc Zool Soc 96(1):317–347. https://doi.org/10.1111/j.1096-3642.1926.tb01551.x CrossRefGoogle Scholar
- Darwin C (1871) Sexual selection and the descent of man. Murray, LondonGoogle Scholar
- Fromhage L, Jennions M, Kokko H (2016) The evolution of sex roles in mate searching. Evolution (N Y) 70:617–624Google Scholar
- Gaskett AC (2007) Spider sex pheromones: emission, reception, structures, and functions. 82:27–48Google Scholar
- Ghislandi PG, Beyer M, Velado P, Tuni C (2017) Silk wrapping of nuptial gifts aids cheating behaviour in male spiders. 28:744–749Google Scholar
- Havrilak JA, Shimmel KM, Rypstra AL, Persons MH (2014) Are you paying attention? Female wolf spiders increase dragline silk advertisements when males do not court. 345–352. doi: https://doi.org/10.1111/eth.12340
- Nentwig W, Kuhn-Nentwig L (2013) Spider ecophysiologyGoogle Scholar
- R Core Team (2014) R: a language and environment for statistical computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
- Roland C, Rovner JS (1983) Chemical and vibratory communication in the aquatic pisaurid spider Dolomedes triton. J Arachnol:77–85Google Scholar
- Taylor PW (1998) Dragline-mediated mate-searching in Trite planiceps (Araneae, Salticidae). J Arachnol:330–334Google Scholar
- van Helsdingen PJ (1965) Sexual behaviour of Lepthyphantes leprosus (Ohlert) (Araneida, Linyphiidae), with notes on the function of the genital organs. Zool Meded 41:15–42Google Scholar