The Natural History and Development of Cuterebra Approximata (Diptera: Cuterebridae) in its Natural Host, Peromyscus Maniculatus (Rodentia: Cricetidae), in Western Montana1

Abstract

In western Montana, Cuterebra approximata shows spring and fall peaks of infection, but apparently maintains a univoltine life cycle. Peromyscus malliculatus serves as the natural host, and an average infection incidence of 14.6% was observed in infected populations. Six other rodent species, sympatric in areas of natural infection, were refractory to C. approximata in laboratory studies. Larval development was rapid in P. manicutatus (22–25 days) but required several days longer when larvae originated from refrigerated or overwintering eggs. Pupae from fall infections enter a prolonged diapause, but those from spring infections develop more rapidly. Adult flies from both groups emerge in late summer. Adult sex ratio in laboratory-reared flies was 1.94: 1 in favor of males.