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Environmentally enriched male mink gain more copulations than stereotypic, barren-reared competitors

Authors :
Steve Bursian
Rupert Palme
David Galicia
Jeff Bowman
Jeannette Kanefsky
Albrecht I. Schulte-Hostedde
Kim T. Scribner
A. C. Napolitano
Georgia Mason
Hélène Filion
María Díez-León
Source :
PLoS ONE, Vol 8, Iss 11, p e80494 (2013), Dadun. Depósito Académico Digital de la Universidad de Navarra, instname, PLoS ONE
Publication Year :
2013

Abstract

Wild carnivores in zoos, conservation breeding centres, and farms commonly live in relatively small, unstimulating enclosures. Under these captive conditions, in a range of species including giant pandas, black-footed ferrets, and European mink, male reproductive abilities are often poor. Such problems have long been hypothesized to be caused by these animals' housing conditions. We show for the first time that rearing under welfare-improving (i.e., highly valued and stress-reducing) environmental enrichments enhances male carnivores' copulatory performance: in mate choice competitions, enriched male American mink (Neovison vison) mated more often than non-enriched males. We screened for several potential mediators of this effect. First was physiological stress and its impact on reproductive physiology; second, stress-mediated changes in morphology and variables related to immunocompetence that could influence male attractiveness; and third, behavioural changes likely to affect social competence, particularly autistic-like excessive routine and repetition ('perseveration') as is reflected in the stereotypies common in captive animals. Consistent with physiological stress, excreted steroid metabolites revealed that non-enriched males had higher cortisol levels and lower androgen levels than enriched conspecifics. Their os penises (bacula) also tended to be less developed. Consistent with reduced attractiveness, non-enriched males were lighter, with comparatively small spleens and a trend to greater fluctuating asymmetry. Consistent with impaired social competence, non-enriched males performed more stereotypic behaviour (e. g., pacing) in their home cages. Of all these effects, the only significant predictor of copulation number was stereotypy (a trend suggesting that low bodyweights may also be influential): highly stereotypic males gained the fewest copulations. The neurophysiological changes underlying stereotypy thus handicap males sexually. We hypothesise that such males are abnormally perseverative when interacting with females. Investigating similar problems in other taxa would be worthwhile, since many vertebrates, wild and domestic, live in conditions that cause stereotypic behaviour and/or impair neurological development.

Details

Language :
English
Database :
OpenAIRE
Journal :
PLoS ONE, Vol 8, Iss 11, p e80494 (2013), Dadun. Depósito Académico Digital de la Universidad de Navarra, instname, PLoS ONE
Accession number :
edsair.doi.dedup.....9e835c2679c2e7cfee94a25b0990974b