Looking Beyond the Surface – Effort Not Appearance in Courtship

http://bugguide.net/node/view/275475/bgimage (accessed on 28 March 2010)

http://bugguide.net/node/view/275475/bgimage (accessed on 28 March 2010)

 

The brush-legged wolf-spider (Schizocosa ocreata) is only 1 out of the more than 2000 species of wolf spiders. Males of the brush-legged wolf-spider have dark pigmentation and tufts of bristles on the tibiae of their forelegs – a conspicuous secondary sexual trait. They employ multimodal courtship display (visual, vibration and semaphore) to attract females for copulation. It was wondered if the tufts or bristles of hair have any impact on females’ preference for mates.

It was found that the tufts made the courtship message easier to detect by females and the removal of the male spiders’ tufts on their forelegs only had an impact when the females could see the males but not feel the vibration signals. In fact, under circumstances when both visual and vibration courtship displays are detected, “female receptivity do not vary with the presence or absence of tufts”.  Instead, females mated more often with males who initiated courtship first and put in more effort in courtship display (lifting their legs up and down in a slow manner and not just wavingof legs).

All these findings suggest that courtship effort is a better predictor of courtship success than ornamentation (tufts of bristles) of brush-legged wolf spiders.  I find this interesting and unique because in most other species, certain physical traits (particularly more attractive “ornamentation”) in males are preferred by females. For example, for the male fiddler crab, the bigger and brighter its claw, the sexier females find it, as it is an indication of its fitness. Thus, selecting “quality mates with good genes” is a part of natural selection. However, there are times in which we should look beyond the exterior to examine what is really underneath and not judge someone (whether animal or human)solely based on physical traits and appearances. Humans too, can take a leaf from the brush-legged wolf-spider (Schizocosa ocreata) when finding a mate.

References

Article – Wolf Spiders” by S. Hart. Animal Communication Project, 25 March 2003. URL: http://acp.eugraph.com/spiders/wolf.html (accessed 30 March 2010).

Scientific Journal – S.J. Scheffer, G.W. Uetz and G.E. Stratton, 1996. Sexual Selection, male morphology, and the efficacy of courtship signalling in two wolf spiders (Araneae: Lycosidae). Journal of Behavioural Ecology and Sociobiology, Volume 38 (1): 17-23. URL:  http://beheco.oxfordjournals.org/cgi/content/abstract/20/6/1242

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