Date of Award


Document Type


Degree Name

Master of Science (MS)




One bat species in North America, Hyotis luclfugus LeConte (Chiroptera: Vespertilionidae), is well known biological 1y, but information concerning its ectoparasites is scattered and generally lacking for the north-central United States* The purpose of this investigation was to obtain information on the distribution, similarity, and abundance of arthropod ectoparasites between mtemity colonies of Little Brown Bats in northwestern Minnesota and northeastern North Dakota,

locations of bat colonies were requested frm various sources in 8 counties in the forest of Minnesota and 9 in the prairie of North Dakota throughout the summer of 1979. The age, sm t and reproductive condition of each bat was determined. Ectoparasites were recovered from hosts by examination under a dissecting microscope. Insects were mounted in Canada balsam for identification. Most snipes were mounted in Moyer's medium. Chiggers and sarcoptid mites were mounted directly from storage in 70% ethanol Into a polyvinyl alcohol and lactophenol medium.

A total of 379 Myoti s luci fiigus (205 adult??, 106 juvenile//, 68 juvenile??} were examined, from 11 colonies in Minnesota (358 specimens and 3 in North Dakota (26 specimens). All colonies were associated with man-made structures and each colony usually consisted of 25 to 150 individuals. Pregnant females carried 1 fetus. The period of juvenile development, as characterized by an increase in body size, weight, pelage, and the attainment of flight, was found to mainly occur in July

A total of 4 species cf Insects and 7 species of mites were taken from 326 of 341 hosts examined. The occurrence and rate of infestation of each species varied between colonies, by collecting date, and the tine of day of host capture. The density of fleas (Myodopsyila ins ignis), bat bugs (Cimex adjunctus), and mites (Macronyssus crosbyi) was found to possibly be related to host reproductive condition, the age of immature hosts, and the roost environment. No differences were noted in ectoparasite burden between male and female juveniles. Collectively, juveniles were found to be highly susceptable to ectoparasite feeding.

Forest colonies in Minnesota had the greatest number of ectoparasite species (11) and the highest similarity of ectoparasite faunas. North Dakota colonies, with 4 species of ectoparasites, were most similar to each other in the lack of ectoparasites, including bat bugs and sarcoptid mites. The widespread distribution of 2 species, Myodopsyiia insignis and Macronyssus crosbyi, accounted for most of the similarity of ectoparasite faunas between forest and prairie colonies.