Prey Selection 167 



(1939) and Swift et al. (1985) both reported Diptera to be the most important 

 food source for the eastern pipistrelle. 



Eptesicus fuscus 



Three taxonomic orders of prey were observed in the fecal samples of 

 three big brown bats. Coleoptera and Lepidoptera were found in 100% of the 

 fecal samples, whereas Diptera was only observed in one (Table 2). The diet of 

 these bats was dominated by Coleoptera (78%). Beetles were fed upon in pro- 

 portions equal to their availability. Lepidoptera appeared to be selectively fed 

 upon. They comprised 21% of the fecal volume, compared to 5% of available 

 insects sampled in the environment (p = 0.056). The small proportion of Diptera 

 observed in fecal samples was not significantly different from their availability. 

 Hymenoptera, Hemiptera, or Homoptera were not observed in the fecal samples. 

 The diet of the bats we examined was similar to that reported in previous stud- 

 ies, in that Coleoptera predominated in the diet (Hamilton 1933, Phillips 1966, 

 Ross 1967 in Freeman 1981, Whitaker 1972, Whitaker 1995). Whitaker (1972) 

 found that 4.3% of the diet was composed of non-flying insects, suggesting that 

 big brown bats may occasionally glean from the ground or foliage. 



Lasiurus intermedius 



The fecal samples of the two northern yellow bats captured were com- 

 posed entirely of Coleoptera and Hymenoptera (Table 2). Coleoptera and 

 Hymenoptera made up 3 1 % and 69% of the fecal samples by volume, respec- 

 tively. No significant difference between percent fecal volume and percent avail- 

 ability was observed for Coleoptera. However, differences between fecal vol- 

 ume and availability of Hymenoptera approached significance (p = 0.067), sug- 

 gesting a feeding preference for this taxa. 



Previous studies reported Coleoptera as the most frequently consumed 

 prey taxa (Sherman 1939, Zinn 1977). Hymenoptera were also found in lower 

 volumes. Ivey (1959) reported observing northern yellow bats foraging in back 

 dune depressions where mosquitoes and flies were abundant. However, in con- 

 trast to Webster et al. (1980), he did not actually witness bats consuming these 

 insects. 



CONCLUSION 

 Despite small sample sizes, we found significant differences among 

 available and consumed prey in all five species of bats studied. Although there 

 are some biases associated with any type of sampling (Taylor and Carter 1961, 

 Rabinowitz and Tuttle 1982); the comparison of the available prey and prey that 

 represented in the fecal samples gives us a greater insight into the complex for- 

 aging habits of some of the bat species found in the Southeast. 



