• Effects of Ectoparasites and Reproductive Class on Roost-Switching and Foraging Behavior of Indiana Bats (Myotis sodalis)

      2012-01-19
      Ectoparasites of bats have been known to cause harm to their hosts and to affect roost-switching. Little research exists on effects ectoparasites may have on roosting and foraging behavior of the federally endangered Indiana bat (Myotis sodalis). From 2008 through 2010, I collected ectoparasite data and documented roost-switching and foraging behavior of Indiana bats on habitat restoration lands owned by the Indianapolis International Airport (IND) in central Indiana. I tested for differences in roosting and foraging behavior between bats with varying ectoparasite loads, and for differences in ectoparasite load, roost-switching frequency, and foraging behavior between different reproductive classes of Indiana bats. I used the volume of ectoparasites of each Indiana bat when analyzing data. I found a significant difference in roost-switching frequency and ectoparasite volume between reproductive classes. Neither reproductive class nor ectoparasite load significantly affected any aspect of foraging behavior. Indiana bats in this study apparently maintained moderate loads of ectoparasites which may not affect foraging and roosting, but the insignificant results found in this study may have been due to a small sample size. The significant difference in roost-switching between reproductive classes likely demonstrates variation in bat thermoregulation. Lactating females and pregnant females have a higher need for group thermoregulation and switch roosts less frequently than post-lactating females and volant juveniles. Because ectoparasites have been found to increase in maternity colonies, volant juveniles and post-lactating females may disperse from the main colony roost and switch roosts more often to avoid higher intensities of ectoparasites.
    • Insect Abundance and Variability in an Urban-Rural Landscape and Comparison to Foraging Habitat Selection of Bats

      Oehler, Nicole M. (2012-01-19)
      I conducted a study of the relationship between prey availability and foraging habitat selection of Indiana bats (Myotis sodalis), big brown bats (Eptesicus fuscus), eastern red bats (Lasiurus borealis) and evening bats (Nycticeius humeralis) in an urban-rural landscape matrix of southwestern Indianapolis. Insects were collected from nine different habitat types found within the range of these species. Insect data were collected from 2006 to 2008 using sticky traps placed in each habitat type. Habitat types were ranked by importance to each bat species (based on previous studies) and then compared to the average number of prey insects captured per habitat sticky trap. Only the average number of insects captured per habitat sticky trap that were big brown bat and eastern red bat prey varied significantly between all nine habitat types. The average number of prey insects captured per habitat sticky trap that were Indiana bat, big brown bat, eastern red bat and evening bat prey were strongly significantly different between sampling dates within seasons. The average number of prey insects captured per habitat sticky trap that were big brown bat and evening bat prey varied significantly between sampling dates between seasons. The average number of prey insects per habitat type did not correlate significantly with habitat selection by any of the four bat species.