Local variation in helminth burdens of Egyptian spiny mice (Acomys cahirinus dimidiatus) from ecologically similar sites: relationships with hormone concentrations and social behaviour

Abstract

A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. AbstractPopulations of Egyptian spiny mice (Acomys cahirinus dimidiatus) in a fragmented montane wadi system in the Sinai showed significant differences in the abundance of gut helminths. Differences in parasite load between populations were positively associated with measures of androgen activity but showed no significant relationship with glucocorticoid activity. Social discrimination tests with adult males from different wadis showed that those from sites with greater helminth abundance were less likely to investigate odours from other males and were less aggressive when subsequently interacting with the odour donors. Subjects showed markedly more investigation towards the odours of males from distant wadis compared with those from their own or immediately neighbouring wadi, but were less aggressive when confronted with odour donors from distant wadis. Despite this, there was a positive relationship between the amount of investigation towards distant male odour and subsequent aggression towards the male. While aggressiveness was positively associated with measures of androgen and glucocorticoid activity, no significant relationship emerged with individual helminth infection. Thus aggressiveness appeared to relate to overall local population levels of infection rather than individual challenge.

Local variation of haemoparasites and arthropod vectors, and intestinal protozoans in spiny mice (Acomys dimidiatus) from four montane wadis in the St Katherine Protectorate, Sinai, Egypt

“…Such differences might lead to local adaptation of mice to their prevailing parasite fauna, a phenomenon that appears to be taking place in relation to androgen metabolism and intra‐specific social behaviour in Ac. dimidatus populations (Barnard et al , 2003 b ). Indeed, it may be the case that populations of mice within wadis (which are usually associated with Bedouin gardens) are locally specialized to a particular parasite fauna.…”

“…In our earlier papers (Behnke et al , 2000, 2004; Barnard et al , 2003 b ), we referred to the host spiny mouse as Acomys cahirinus dimidiatus . Here we refer to the host as Ac.…”

“…In earlier papers we showed that the helminth communities of bank voles vary markedly between subpopulations of voles living in forest patches that are ecologically very similar but segregated from each other by natural barriers (Behnke et al , 2001; Barnard et al , 2002, 2003 a ), and that the key indicators of helminth community structure are stable in the medium term (Bajer et al , 2005). Similarly, helminth communities in spiny mice Acomys dimidiatus differ profoundly between neighbouring but isolated wadis in the mountains of the Sinai Peninsula (Behnke et al , 2000, 2004; Barnard et al , 2003 b ). In contrast to studies of rodent helminths, there are few studies of site‐specific variation in haemoparasitic infections or in protozoan infections of the intestinal tract.…”

Endogenous development, pathogenicity and host specificity of Eimeria cahirinensis Couch, Blaustein, Duszynski, Shenbrot and Nevo, 1997 (Apicomplexa: Eimeriidae) from Acomys dimidiatus (Cretzschmar 1826) (Rodentia: Muridae) from the Near East

“…have been examined for endoparasites by several authors, who reported mostly cestodes and oxyurid nematodes (Hussein and Kalantan 1993;Behnke et al 2000;Barnard et al 2003). Only a single Eimeria species, E. cahirinensis Couch, Blaustein, Duszynski, Shenbrot andNevo, 1997 (Couch et al 1997), identified on the basis of oocyst morphology, has been reported from these hosts.…”

Towards an integrative model of sociality in caviomorph rodents

“…Such conditions also could affect social interactions that, in turn, can affect social structure. Among the most likely mechanisms linking stress response and fitness are the effects on the cellular and humoral ability to mount an immune response against pathogens (Keita et al 2007; Ndong et al 2007), which in turn influences parasite infection (Barnard et al 1998, 2003) and resistance (Kiank et al 2006; Morales et al 2006; Smith et al 1996; but see Barnard et al 2003). Research aimed at determining the links between stressors such as parasitism, the stress response, and fitness would increase our understanding of the evolutionary significance of intra- and interspecific variation in sociality in caviomorphs.…”