1 6 4 Timothy C. Carter et al. 



tures between fecal volume and prey availability were noted except that 

 Homoptera occurred in significantly lower volume (p < 0.001) in fecal samples 

 than were available in the environment. The relatively large number of evening 

 bats netted allows for a comparison between adult males (n = 16), adult females 

 (n = 41), and juveniles (n=42) of the percent volume of insect taxa in fecal sam- 

 ples to the percent availability in environment (Table 1). 



Regardless of sex and age, the fecal volume of evening bats was com- 

 posed primarily of Coleoptera, Hymenoptera, and Hemiptera (combined these 

 groups comprised 88% or more of the diet). Adult males consumed significant- 

 ly fewer Coleoptera (p = 0.001) and Homoptera (p < 0.001) than were available 

 in the environment (Table 1). The large proportion of Hymenoptera in fecal sam- 

 ples of males compared to availability was not significant (p = 0.071), but sug- 

 gests a feeding preference. Adult males consumed smaller proportions of Lepi- 

 doptera, Hemiptera, and Diptera than did males or juveniles. Combined, these 

 taxa constituted only 23.5 % of the diet and were consumed in roughly equiva- 

 lent proportion to their availability in the environment (21%). Adult females 

 showed little feeding selectivity. Homoptera differed significantly (p = 0.004) 

 between the percent volume in the fecal samples and their availability in the 

 environment. However, these comprised only a very small portion (0.5 %) of the 

 diet. The taxa comprising over 99.5% of the fecal contents were consumed in 

 equal proportion to their availability in the environment. Juvenile evening bats 

 consumed similar prey to that of adult males and females. However, their prey 

 consisted of significantly fewer Coleoptera (p = 0.056), Homoptera (p < 0.001), 

 and Diptera (p < 0.001) than were available in their environment. 



Significant differences in fecal volume of prey species were observed 

 between adult male and female evening bats. Male evening bats consumed sig- 

 nificantly fewer Coleoptera (p = 0.025) than females and also significantly fewer 

 than in proportion to their availability (Table 1, Figure 1). Males also consumed 

 significantly more Hymenoptera (p = 0.039) than females, and in significantly 

 higher proportion to their availability. This might be related to differences in the 

 physiological state and metabolic requirements of males and females during the 

 time of the year of our study (e.g., parturition and lactation). Adult females are 

 expected to be under high levels of nutritional stress and coupled with time con- 

 straints imposed by offspring, might not be able to be as selective in their diets 

 as adult males. Juveniles are not as constrained by time or energy as they are by 

 their lack of foraging experience. Juveniles may be less selective, eating what- 

 ever they can catch. Adult males are not restricted by time constraints, experi- 

 ence or energy demands, allowing them more dietary selectivity. 



A few reports on the foraging habits of the evening bat are available 

 (Ross 1967 in Freeman 1981, Whitaker 1972, Zinn 1977, Whitaker and Clem 

 1992, Feldhamer et al. 1995). Most of these studies had small sample sizes, and 

 none compared diet to relative prey abundance. Coleoptera were generally 



