MASS. EXPERIMENT STATION BULLETIN No. 285 



Figure 2. 



-Number of Punctures Made In Apples by Twenty Plum CurcuHos when 

 Confined at Low, Normal, and High Temperatures. 

 Waltham, Mass., 1930 



INSECTARf 



--ffOOT CELLAR 

 ■o— CUE £N HOUSE 



19 20 £1 32 S3 24 a 16 2710 £9 30 %l 12 3 4 5 6 7 B 9 10 II 12 13 14 IS 16 17 19 



MAY JUNE 



Activity of Beetles 



Preliminary Experiments in 1930 



The first experiments relating to the effect of temperature on the activity of 

 the plum curculio were made in a root cellar, a greenhouse, and an open-air 

 insectary. The temperature in the root cellar was always below 70 ° F. and repre- 

 sented moderately cool conditions, while that in the greenhouse was always above 

 70° F., reaching over 100° F. on warm, sunny days, and represented warm 

 conditions. Records of the activity of 20 beetles were made daily from May 19 

 to June 18 which was the period of greatest normal activity. In the root cellar, 

 each beetle made an average of 31.45 punctures; in the insectary, 59.55; and in 

 the greenhouse, 99.55. As shown in Table 2, the total number of punctures at 

 normal outdoor temperatures was approximately twice as many as under cool 

 conditions, and one-half as many as at high temperatures. Figure 2 shows the 

 daily fluctuation in activity which is in direct relation to the outside temperature, 

 and this is reflected in the records for both the greenhouse and root cellar where 

 the temperature was only partially controlled. 



Table 2. — Activity of Twenty Plum Curculio Beetles Each at Low, Normal, 

 AND High Temperatures. Waltham, Mass., May 19 to June 18, 1930 



A nalysis of Insectary Records 



An analysis of the insectary records for 1927 to 1930 inclusive shows that a 

 similar stimulation in activity corresponding with the maximum daily tempera- 

 ture has been apparent throughout the life history studies. When the records 

 of daily activity are grouped according to each ten degrees of maximum ten pera- 

 ture (Table 3), there is a steady but variable gain in the number of punctures 



