Determinants of Helminth Infection in a Subterranean Rodent, the Cape Dune Mole-Rat (Bathyergus suillus)

Abstract

The helminth fauna of the largest bathyergid, the Cape molerat (Bathyergus suillus) was studied throughout an entire calendar year. The species richness encountered was low, with only 3 species of nematodes (Longistriata bathyergi, Mammalakis macrospiculum, and Trichostrongylus sp.) and 2 species of cestodes (Taenia sp. and Rodentolepis sp.). At less than 10%, the prevalence for all helminths species was similarly low and may be a result of the solitary lifestyle and the subterranean habitat exploited by this rodent. Clear seasonal patterns were apparent for the most common nematode (L. bathyergi), and prevalence and abundance were highest among non-pregnant females compared to males and pregnant females. Dispersal patterns associated with the mating system of the host could explain this pattern. In contrast, the prevalence of the most common cestode (Taenia sp.) was neither determined by season nor host sex, suggesting that foraging habits may constantly expose B. suillus to this parasite.Although parasites are ubiquitous, individuals within host populations often show marked variation in parasite prevalence and abundance, and the parasite distribution is highly skewed (Poulin, 2007). Such heterogeneities can be caused by both intrinsic and extrinsic factors, which determine the exposure and susceptibility of hosts to parasites. Effects of intrinsic factors such as host sex have been reported for many vertebrate species (Poulin, 1996;Klein, 2004). Gender bias has been alternatively linked to body size differences (Moore and Wilson, 2002), differences in space use patterns (e.g., Scantlebury et al., 2010), and the immunosuppressive effects of androgens (Folstad and Karter, 1992;Klein, 2004). Extrinsic factors such as rainfall and temperature, on the other hand, often act on the parasite directly, resulting in variation in the spatial and temporal distribution of parasites (Poulin, 2007). Such extrinsic factors and, as a consequence, the distribution of parasites often differ between habitats, and, accordingly, habitat use can determine the exposure of hosts to parasites (Froeschke et al., 2010).It has repeatedly been noted that the subterranean niche of fossorial rodents may limit their exposure to parasites, and this has been linked to the low parasite species richness encountered in a number of subterranean rodents (Gardner, 1985;Hafner et al., 2000;Rossin and Malizia, 2002;Rossin et al., 2010). Rodents from a range of families have adapted to a subterranean lifestyle, and, despite their diverse origin, they show remarkable similarities with respect to morphology, physiology, and basic life history traits. Their cryptic lifestyle has contributed to the paucity of information about their parasite fauna. However, efforts have been made, and studies on the North American geomyids, the South American octodontids, as well as the European spalacines have reported a number of cestodes, nematodes, and coccidian parasites for these rodents (Gardner, 1985;Hafner et al., 2000;Rossin and Malizia, 2002;Rossin et ...

First Report of Gastrointestinal Parasites from Ansell's Mole-Rat (Fukomys anselli) in Zambia

“…Similar to other subterranean rodents the observed helminth species richness for F. anselli was low supporting the hypothesis that the subterranean niche limits the exposure to parasites (Rossin et al, 2010;Lutermann and Bennett, 2012). At the same time, with 4 nematodes (as specimens identified as Protospirura sp.…”

“…At the same time, with 4 nematodes (as specimens identified as Protospirura sp. likely belong to P. numidica and P. muricola, however, their poor condition did not permit a reliable identification beyond genus level) and 2 cestode species the helminth community of F. anselli exhibits a greater species diversity than has previously been reported for the genus as well as for any other bathyergid species while prevalence and abundance of these species is comparatively low (Scharff et al, 1997;Tenora et al, 2003;Viljoen et al, 2011;Lutermann and Bennett, 2012;Lutermann et al, 2013;Archer et al, 2017). Since sample sizes were relatively small for F. kafuensis and F. mechowi (Scharff et al, 1997), it remains unclear whether a similarly great species diversity is more common in the genus Fukomys.…”

“…Notable exceptions are subterranean species including many members of the Ctenomyidae and Bathyergidae. They only sustain a small number of helminth species which is generally attributed to the limited host exposure in burrow systems (Rossin et al, 2010;Lutermann and Bennett, 2012). However, studies of the helminth fauna of subterranean rodents are scant and hence our knowledge of their helminth fauna might be biased.…”

Helminth communities in murid rodents from southern and northern localities in Lao PDR: the role of habitat and season

“…More rarely, the roles of habitat and the level of human influence have been specifically investigated (Udonsi 1989;Kataranovski et al, 2008;Chaisiri et al, 2010;Froeschke et al, 2010;Milazzo et al, 2010;Lutermann & Bennett, 2012).…”

The Distribution of Gastrointestinal Parasites in Two Populations of Common Mole-Rats (Cryptomys hottentotus hottentotus)

“…As in other subterranean mammals, low species richness of macroparasites is common in bathyergids (Viljoen et al, 2011;Lutermann and Bennett, 2012;Lutermann et al, 2013Lutermann et al, , 2015Archer et al, 2014). Mammalakis macrospiculum has previously only been reported from Bathyergus suillus (Schreber 1782), which occurs sympatrically with our study species in the mesic habitat and this may account for the host sharing (Inglis, 1991;Bennett and Faulkes, 2000;Lutermann and Bennett, 2012). Specimens of Neoheligmonella sp.…”