BOTFLY (DIPTERA, OESTRIDAE) PARASITISM OF ORD KANGAROO RATS (DIPODOMYS-ORDII) AT SUFFIELD-NATIONAL-WILDLIFE AREA, ALBERTA, CANADA

During field study of Ord's kangaroo rat (Dipodomys ordii) at Suffield National Wildlife Area, Alberta, Canada, a high prevalence of parasit ism by botfly (Diptera: Oestridae) larvae was observed. Botflies have not previously been documented as parasites of kangaroo rats. Botfly p arasitism could have a significant impact on the growth, survival, and reproduction of Ord's kangaroo rat, which is considered a vulnerable species in Canada. Therefore, it is important to investigate how botfl y parasitism varies with season and with gender or age of host. In 199 5, 525 individual kangaroo rats were caught by nightlighting and live trapping for a total of 952 capture records. Upon capture, each kangar oo rat was ear-tagged and thoroughly examined for parasites and wounds . Third-instar botfly (Cuterebra polita) larvae were observed in kanga roo rats between 16 June and 23 August. Prevalence was 34% based on 45 4 kangaroo rats sampled during that time, whereas the mean intensity w as 2.3 larvae per infested host (n = 156, range = 1-11). In contrast t o some other studies of botfly parasitism of rodents, there were no ge nder or age biases in either prevalence or intensity of infestation. T he index of dispersion was 2.8, indicating that the parasites were agg regated in hosts. Botfly parasitism could be an important factor affec ting northern populations of kangaroo rats; future investigations into the potential effects of botfly larvae on host fitness are warranted.