PHYSIOLOGICAL STUDIES ON HIBERNATION IN 



THE POTATO BEETLE, LEPTINOTARSA 



DECEMLINEATA SAY. 1 



DAVID E. FINK. 



(From the Bureau of Entomology, United States Department of Agriculture, 



Washington, and the Zoological Laboratory, University 



of Pennsylvania, Philadelphia.) 



CONTENTS. 



INTRODUCTION 381 



MATERIAL AND METHODS 383 



EXPERIMENTS AND DISCUSSION 384 



1. Food Experiments 384 



(a) Number of feeding days before hibernation 385 



(b) Breeding activities 387 



(c) Metabolism during feeding experiments 388 



2. Preparation for Hibernation 390 



(a) Water and fat content ' , . 391 



(b) Hibernating gland 392 



3. Metabolism of Active, Starving and Hibernating Beetles 395 



(a) Respiratory quotient 397 



4. Recovery from Hibernation 399 



(a) Adjustment of the Water Content 400 



5. Catalase and Oxidase Activity 401 



(a) Catalase 401 



(6) Oxidase 402 



SUMMARY 403 



BIBLIOGRAPHY 404 



INTRODUCTION. 



An inquiry into the nature and cause of the phenomenon of 

 hibernation has for many years engaged the attention of investi- 

 gators. The literature on the physiological study of hibernating 

 mammals covers a wide range of research, the most significant 

 of which appears to be into the effects of temperature, food and 

 gaseous exchange. The experimental evidence brought forward 

 by Dubois (10), Pembrey (17), Valentin (25), Weinland and 

 Riehl (29) and others, indicates that hibernating animals placed 



1 A thesis in zoology presented to the Faculty of the Graduate School of the 

 University of Pennsylvania in partial fulfillment of the requirement for the degree 

 of Doctor of Philosophy. 



381 



