TEMPERATURE AS A FACTOR IN THE DEVELOP- 

 MENT OF ANTS. 







WITH FURTHER OBSERVATIONS ON ANTS DEPRIVED OF FOOD. 



ADELE M. FIELDE. 



Some recent experiments made by me lead to the conclusion 

 that temperature is a dominant factor in the development of ants ; 

 that, other things being equal, it determines the time of the de- 

 posit of the eggs, the length of the larval period, and the hour 

 of exit from the cocoon ; and that the developing young of un- 

 like species of ants are differently affected by the same degree of 

 heat. It also appears probable that unlike species of ants develop 

 and deposit their eggs at different temperatures, fixed for each 

 species. 



The greater activity of the adult ants in higher temperatures, 

 with the increased movement of the anterior end of the larva 

 which may be observed when the temperature rises, and the 

 quickening of the pupae which occurs in the hottest days, are 

 doubtless an effect of the stimulation of metabolism by heat. 



EXPERIMENT A. 



My N. queen Catnpoiiotus pennsylvanicus laid eggs in the first 

 week in August, 1903, which were kept in my living room where 

 the temperature seldom rose above 70 F. or 21 C, and the 

 earliest ant to issue from these eggs hatched on April 25, 1904, 

 when the temperature had risen to 78 F. or 26 C. On July 

 14, 1904, I removed this queen to a new nest, where she was kept 

 at a temperature that seldom rose above 70 F., and she laid no 

 eggs until after I had, on November 20, 1904, removed her to a 

 room where the usual temperature was from 82 to 85 F., rarely 

 falling to 70 F. and occasionally rising to 90 F. On Decem- 

 ber 2 I observed twenty eggs, which had increased to sixty on 

 December 11. The first larva appeared on December 18. On 

 December 30 all the eggs had hatched and there were several 

 tens of larvae. The first cocoon was spun on January 8, and the 



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