Ectoparasites in an Urban Population of Big Brown Bats (Eptesicus Fuscus) in Colorado

Abstract

Ectoparasites of an urban population of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado, were investigated during summers 2002, 2003, and 2004. Eleven species of ectoparasites were found (the macronyssid mite Steatonyssus occidentalis, the wing mite Spinturnix bakeri, the myobiid mites Acanthophthirius caudata and Pteracarus aculeus, the chirodiscid mite Alabidocarpus eptesicus, the demodicid mite Demodex sp., the chigger Leptotrombidium myotis, the soft tick Carios kelleyi, the batfly Basilia forcipata, the batbug Cimex pilosellus, and the flea Myodopsylla borealis). Five species were analyzed by prevalence and intensity (C. pilosellus, M. borealis, L. myotis, S. bakeri, and S. occidentalis) based on 2161 counts of 1702 marked individual bats over the 3 summer study periods. We investigated 4 factors potentially influencing prevalence and intensity: age class of the host, reproductive status of adult female hosts, roosts in which the hosts were found, and abiotic conditions during the year sampled. The macronyssid mite, S. occidentalis, was the most prevalent and abundant ectoparasite. Adult big brown bats had more ectoparasites than volant juveniles for most of the species analyzed. In a sample of known age bats at 1 large colony, bats of 4 yr of age or greater had higher ectoparasite loads of S. occidentalis and S. bakeri when compared with younger bats. Lactating female bats had the highest prevalence and intensities of most ectoparasites. Annual differences in ectoparasite prevalence and intensity were related to temperature and humidity, which can affect the nidicolous species of ectoparasites. Residents of 2 buildings sprayed insecticides in response to Cimex sp., and this appeared to reduce ectoparasitism of S. occidentalis and C. pilosellus present at these buildings. Intensity of S. occidentalis had no influence on annual survival of big brown bats.

The chiggerflea Hectopsylla pulex (Siphonaptera: Tungidae) as an ectoparasite of free-tailed bats (Chiroptera: Molossidae)

“…Pearce and O'Shea (2007) found that large adult brown bats had more ectoparasites than volant juveniles for most of the species analysed. Mite load and the condition of the bats were negatively correlated in a study by Lourenço and Palmeirim (2007) and the information available suggests that this may be due to an effect of parasitism.…”

The first fossil streblid bat fly, Enischnomyia stegosoma n. g., n. sp. (Diptera: Hippoboscoidea: Streblidae)

“…At least one species of the genus, E. fuscus (Palisot de Beauvois), occurs today in Hispaniola (Rodríguez-Durán & Kunz, 2001). Extant species of Eptesicus are parasitised by nycteribiid bat flies of the genus Basilia Miranda Ribeiro, 1903 in Panama, Venezuela and Colorado (Guimarães, 1966;Pearce & O'Shea, 2007). Another possible host candidate for Enischnomyia stegosoma is a tree-roosting red bat of the genus Lasiurus H. Allen.…”

Lack of Association between Ectoparasite Intensities and Rabies Virus Neutralizing Antibody Seroprevalence in Wild Big Brown Bats (Eptesicus fuscus), Fort Collins, Colorado

“…We used an analysis of relative variable importance (Burnam andAnderson 2002, Neubaum et al 2006) using Akaike's Information Criteria corrected for sample size (AICc) to determine the relative importance of these variables to the seroprevalence of RVNA in big brown bats. Our objectives in this analysis did not include testing of hypotheses about factors influencing ectoparasite intensities, which are explored by Pearce and O'Shea (2007), but we focus, instead, on factors influencing the presence of RVNA.…”