The effect of canine tooth wear on the diet of big brown bats (Eptesicus fuscus)
The purpose of this study was to determine whether canine wear influences the diet of big brown bats (Eptesicus fuscus). We hypothesized that tooth wear reduces the ability to consume hard-bodied insects, such as beetles, and that older E. fuscus (those with worn canines) would thus include fewer beetles in their diet than younger individuals (those with less-worn canines) do. We examined 600 fecal pellets collected from 60 female bats captured at a single maternity colony in southeastern Alberta, Canada. The diets of two groups were similar in composition, despite considerable differences in canine wear. Diets were dominated by beetles (Coleoptera), which accounted for 30 to 40% of the identifiable food items. Younger bats included more beetles in their diet, although the difference was not statistically significant. The results suggest that older bats are still able to use their worn canines to effectively puncture hard exoskeleton, perhaps because of the angular shape of the worn teeth.
- Adams, R. 1996. Size-specific resource use in juvenile little brown bats, Myotis lucifugus (Chiroptera: Vespertilionidae): is there an ontogenetic shift? Canadian Journal of Zoology, 74: 1204-1210.
- Brigham, R. M„ and M. B. Saunders. 1990. The diet of big brown bats (Eptesicus fuscus) in relation to insect availability in southern Alberta, Canada. Northwest Science, 64: 7-10.
- Evans, A. R., and G. D. Sanson. 1998. The effect of tooth shape on the breakdown of insects. Journal of Zoology (London), 246: 391-400.
- Frank, C. L. 1991. Adaptations for hibernation in the depot fats of a ground squirrel (Spermophilus beldingi). Canadian Journal of Zoology, 69: 2707-2711.
- Freeman, P. W. 1979. Specialized insectivory: beetle- eating and moth-eating molossid bats. Journal of Mammalogy, 60: 467-179.
- Freeman, P. W. 1992. Canine teeth of bats (Microchiroptera): size, shape, and role in crack propagation. Biological Journal of the Linnean Society, 45: 97-115.
- Freeman, P. W. 1998. Form, function, and evolution in skulls and teeth of bats. Pp. 140-156, in Bat biology and conservation (T. H. Kunz and P. A. Racey, eds.). Smithsonian Institution Press, Washington D.C., 365 pp.
- Freeman, P. W., and W. N. Weins. 1997. Puncturing ability of bat canine teeth: the tip. Pp. 225-232, in Life among the muses: papers in honor of James S. Findley (T. L. Yates, W. L. Gannon, and D. E. Wilson, eds.). University of New Mexico Press, Albuquerque, 290 pp
- Geiser, F., and G. J. Kenagy. 1993. Dietary fats and torpor patterns in hibernating ground squirrels. Canadian Journal of Zoology, 71: 1182-1186.
- Hall, J. S. 1957. Longevity records and notes on tooth wear of bats. Journal of Mammalogy, 38: 407-409.
- Hamilton, I. M., and R. M. R. Barclay. 1998. Diets of juvenile, yearling, and adult big brown bats (Eptesicus fuscus) in southeastern Alberta. Journal of Mammalogy, 79: 764-771.
- Holroyd, S. L. 1993. Influences of some extrinsic and intrinsic factors on reproduction by big brown bats (Eptesicus fuscus) in southeastern Alberta. M.S. Thesis, University of Calgary, Calgary, Canada, 126 pp.
- Kay, R. F., and W. S. Sheine. 1979. On the relationship between chitin particle size and digestibility in the primate Galago senegalensis. TheAmerican Journal of Physical Anthropology, 50: 301-308.
- Lanyon, J. M., and G. D. Sanson. 1986. Koala (Phascolarctos cinereus) dentition and nutrition. II. Implications of tooth wear in nutrition. Journal of Zoology (London), 209: 69-181.
- Marchetti, K., and T. Price. 1989. Differences in the foraging of juvenile and adult birds: the importance of developmental constraints. Biological Reviews, 64: 51-70.
- McArthur, C„ and G. D. Sanson. 1988. Tooth wear in eastern grey kangaroos (Macropus giganteus) and western grey kangaroos (Macropus fuliginosus), and its potential influence on diet selection, digestion, and population parameters. Journal of Zoology (London), 215: 491-504.
- McLeod, M. N., and D. J. Minson. 1969. Sources of variation in the in vitro digestibility of tropical grasses. Journal of the British Grassland Society, 24: 244-249.
- Rolseth, S. L., C. E. Koehler, and R. M. R. Barclay. 1994. Differences in the diets of juvenile and adult hoary bats, Lasiurus cinereus. Journal of Mammalogy, 75: 394-398.
- Schalk, G., and R. M. Brigham. 1995. Prey selection by insectivorous bats: are essential fatty acids important? Canadian Journal of Zoology, 73: 1855-1859.
- Shiel, C„ C. McAney, C. Sullivan, and J. Fairley. 1997. Identification of arthropod fragments in bat droppings. Occasional Publication of the Mammal Society, The Mammal Society, London, 17: 1-48.
- Strait, S. G. 1993. Molar morphology and food texture among small-bodied insectivorous mammals. Journal of Mammalogy, 74: 391-402.
- Unger, P., and M. Williamson. 2000. Exploring the effects of tooth wear on functional morphology: a preliminary study using dental topographic analysis. Palaeontologica Electronica, 3: 1-18.
- Werner, E. E., and J. F. Gilliam. 1984. The ontogenetic niche and species interactions in size-structured populations. Annual Review of Ecology and Systematics, 15: 393-425.
- Whitaker, J. O., Jr. 1988. Food habits analysis of insectivorous bats. Pp. 171-179, in Ecological and behavioral methods for the study of bats (T. H. Kunz, ed.). Smithsonian Institution Press, Washington D.C., 533 pp.
- Whitaker, J. O., Jr. 1995. Food of the big brown bat Eptesicus fuscus from maternity colonies in Indiana and Illinois. The American Midland Naturalist, 134: 346-360.
- Yoerg, S. I. 1994. Development of foraging behaviour in Eurasian dippers, Cinclus cinclus, from fledging until dispersal. Animal Behaviour, 47: 577-588.