Difference in glucose tolerance between phytophagous and insectivorous bats
Bats are mostly insectivorous or phytophagous. It is hypothesized that bats are evolved from small insectivorous mammals. Therefore, the digestive and metabolic systems of phytophagous and insectivorous bats must have evolved differently to adapt to their dietary habits. To investigate the difference in sugar tolerance in bats, we determined changes in blood glucose levels after intraperitoneal (i.p.) injection of glucose in three species of phytophagous and four species of insectivorous bats under resting conditions. Results showed that phytophagous bats eliminated blood glucose faster than insectivorous bats. All three species of fruit bats reduced blood glucose to fasting levels within 30–45 min, whereas all insectivorous bats failed to lower blood glucose to fasting levels even 120 min after i.p. glucose injection. Taken together, results of this study suggest that bats have undergone adaptations and become diversified in dietary habits.
KeywordsGlucose clearance Phytophagous bats Insectivorous bats
We thank Hui Liu, Qin Zhang, Qiqi Shen, and Jiao Zhao for their help with animal experiments, Quangsheng Liu for valuable advices. We also thank Prof. Yi-Hsuan Pan for providing experimental material. This work was supported by grants from the GDAS Special Project of Science and Technology Development (2017GDASCX-0107 and 2018GDASCX-0107), the Science & Technology Planning Project of Guangzhou (201707010128), and the Guangdong Provincial Science and Technology Program (2018B030324001).
XP, XH, and LZ designed the study. XP performed the experiments. XP, XH, YS, JL, HX, and JW collected bats. XP, LZ, XH, YS, JL, HX, and JW analyzed the data and wrote the manuscript.
- Altringham JD (1996) Bats: biology and behaviour. Oxford University Press, OxfordGoogle Scholar
- Balcombe JP, Barnard ND, Sandusky C (2004) Laboratory routines cause animal stress. J Am Assoc Lab Anim Sci 43(6):42–51Google Scholar
- Caviedes-Vidal E, Chediack JG, Cruz-Neto AP et al (2004) Sugar absorption in bats. Are they mammals or birds? Integr Compar Biol 44(6):534Google Scholar
- Chippendale GM (1978) The functions of carbohydrates in insect life processes. In: Rockstein M (ed) Biochemistry of insects. Academic Press, London, pp 2–57Google Scholar
- del Rio CM (1994) Nutritional ecology of fruit-eating and flower-visiting birds and bats. The digestive system in mammals: food, form and function. Cambridge University Press, Cambridge, pp 103–127Google Scholar
- Hill JE, Smith JD (1984) Bats: a natural history. Cambridge University Press, CambridgeGoogle Scholar
- Karasov WH, Hume ID (1997) Vertebrate gastrointestinal system. Compr Physiol 119:853–859Google Scholar
- Keegan DJ (1984) Glucose absorption in the fruit bat studied using the intestinal ring method. S Afr J Sci 80:132Google Scholar
- Kunz TH (1988) Ecological and behavioral methods for the study of bats. Smithsonian Institution Press, WashingtonGoogle Scholar
- Kunz TH, Fenton MB (2003) Bat ecology. The University of Chicago Press, ChicagoGoogle Scholar
- Widmaier EP, Kunz TH (1993) Basal, diurnal, and stress-induced levels of glucose and glucocorticoids in captive bats. J Exp Biol 265(5):533–540Google Scholar
- Zhang Q (2017) Comparison of glucose metabolism capacity and islet cell characteristics between Cynopterus sphinx and Hipposideros armiger. Central South University of Forestry and Technology, ChangShaGoogle Scholar