Please use this identifier to cite or link to this item:
|Title:||Eunuchs are better fighters||Authors:||Kralj-Fišer, S.
Orb web spider
|Issue Date:||May-2011||Citation:||Kralj-Fišer, S., Gregorič, M., Zhang, S., Li, D., Kuntner, M. (2011-05). Eunuchs are better fighters. Animal Behaviour 81 (5) : 933-939. ScholarBank@NUS Repository. https://doi.org/10.1016/j.anbehav.2011.02.010||Abstract:||Genital amputation, that is, genital damage or loss, seems maladaptive because it renders the amputee functionally sterile, but is nevertheless common in sexually dimorphic spiders. In these species, male genital amputation correlates with plugging of female genitals and with sexual cannibalism. Genital amputation in male spiders may be partial or full; the latter is known as the eunuch phenomenon. We tested two adaptive hypotheses about eunuch behaviour in an orb web spider, Nephilengys malabarensis: (1) the plugging hypothesis (i.e. broken male genitals (palps) effectively plug the female genitals) and (2) the better fighter hypothesis (i.e. eunuch males are better fighters than their intact rivals). By staging mating trials, we documented genital amputation (occurrence and frequency), sexual cannibalism and genital organ reuse, morphologically examined plugs to infer their effectiveness, and conducted a series of male-male contests to determine whether eunuch males were better fighters. Copulations always resulted in amputation of the palps: 87.5% of males became eunuchs directly during copulation and plugged females, while 12.5% of males first partially damaged the palps and then severed them after copulation. Sexual cannibalism and plugging effectiveness both reached 75%. Eunuchs guarded females, were highly aggressive and active, and initiated and won contests more often, whereas intact males and half-eunuchs showed significantly lower levels of guarding behaviour, aggression and general activity. Thus, both hypotheses are supported and we conclude that the eunuch phenomenon is adaptive. © 2011 The Association for the Study of Animal Behaviour.||Source Title:||Animal Behaviour||URI:||http://scholarbank.nus.edu.sg/handle/10635/100611||ISSN:||00033472||DOI:||10.1016/j.anbehav.2011.02.010|
|Appears in Collections:||Staff Publications|
Show full item record
Files in This Item:
There are no files associated with this item.
checked on Jan 31, 2023
WEB OF SCIENCETM
checked on Jan 24, 2023
checked on Feb 2, 2023
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.