Eimerian guilds (Apicomplexa: Eimeriidae) in Richardson's (Spermophilus richardsonii) and Wyoming (Spermophilus...

Feces of Richardson's ground squirrels (Spermophilus richardsonii) were examined to determine occurrence and prevalence of eimerian species and to compare guilds in these hosts to previously described guilds from Wyoming ground squirrels (Spermophilus elegans). Six species of Eimeria were collected from 100 Richardson's ground squirrels: Eimeria beecheyi (36% infected); Eimeria bilamellata (13%); Eimeria callospermophili-Eimeria morainensis complex (41%); Eimeria lateralis (6%); and Eimeria spermophili (9%). The species composition and prevalences were essentially identical in the 2 congeneric hosts. Three species were consistently more (> 30%) and 3 were consistently less (< 20%) prevalent in both host species. Furthermore, in both squirrel species the rare species were more prevalent in juveniles. Eimerian guilds such as these may be common to many species of ground-dwelling sciurid squirrels. The report of E. beecheyi in Richardson's ground squirrel constitutes a new host record for this species.