CONTROL OF THE CIGARETTE BEETLE 



11 



Table 3. — Cigarette beetles caught in closed-storage warehouses 1 filled with Turkish 

 tobacco, in relation to temperature and season, experiment 3, 1933 



Date 



Inter- 

 val 



Traps 



Beetles caught 



Total 



Average 

 per trap 



Temperature 



Average 

 maxi- 

 mum 



Average 

 mini- 

 mum 



M< 



May 26. 

 June9.. 

 June 23 _ 

 July 7.. 

 July 17. 

 July 24 

 Aug. 7_. 

 Aug. 21. 

 Aug. 2S_ 

 Sept. 7. 

 Sept.9. 

 Sept. 13 

 Sept. 20. 

 Sept. 29. 

 Oct. 4 3_ 



Days 

 2 14 

 14 

 14 

 14 

 10 

 7 

 14 

 14 

 7 

 10 

 2 

 4 

 7 

 9 

 5 



Number 

 11 

 40 

 40 

 40 

 40 

 55 

 57 

 55 

 55 

 53 

 59 

 ' 64 



60 



Number 



300, 400 

 3, 134, 900 

 3, 605, 450 

 776, 600 

 5, 050, 000 

 10, 958, 000 

 42, 942, 000 



30, 758, 000 

 24, 961, 000 

 20, 042, 8C0 



31, 923, 050 

 61, 095, 600 

 39, 625, 000 

 31, 096, 550 

 23, 693, 900 



Number 



27, 309 



78, 373 



90, 136 



19, 415 



126, 250 



199, 236 



753, 368 



559, 236 



453, 836 



345, 556 



541, 069 



954, 619 



660, 417 



518, 276 



394, 898 



'F. 

 73.0 

 75.0 

 76.0 

 78.0 

 76.0 

 79.0 

 78.5 

 77.5 

 76.0 

 73.5 

 77.5 

 77.5 

 74.5 

 71.5 

 67.5 



i Total space, 3,125,000 cubic feet. 



2 Traps started on May 12. 



3 The experiment was terminated on Oct. 4, because the warehouses were fumigated with hydrocyanic 

 acid gas on this date. 



SEX RATIOS 



The writers have been unable to find any external characters on 

 adults of the cigarette beetle by which males can be distinguished 

 from females. During the summer of 1932 a method for determining 

 sex ratios in samples of beetles taken from the traps was developed. 4 

 The beetles were soaked overnight in a 10-percent solution of potas- 

 sium hydroxide, and were than placed in a small glass dish containing 

 glycerin. The bodies of the beetles were sufficiently cleared by this 

 treatment to reveal the genitalia when examined under the binocular 

 microscope. After becoming more familiar with the anatomy of the 

 beetles, the writers found it practicable to place the specimens in 

 glycerin and dissect them under the binocular microscope. In the 

 experiments conducted in 1932, 5,878 beetles were examined in this 

 manner, and 2,150, or 36.6 percent, were males, while 3,728, or 63.4 

 percent, were females. During 1933, of 1,140 beetles examined, 497, 

 or 43.6 percent, were males and 643, or 56.4 percent, were females. 



EGGS IN BODIES OF TRAPPED FEMALES 



On August 10 a sample containing 110 female cigarette beetles 

 was collected from a trap that had been in operation 16 hours, and the 

 beetles were dissected. An average of only 4.4 eggs per female was 

 found. Because of this small number, it was decided to make other 

 dissections at varying intervals. Another sample of 110 females 

 was dissected on August 21, after the trap had been in operation for 

 36 hours. An average of 8.5 eggs per female was found. On Septem- 

 ber 6, 3 samples of 10 females each were taken from a trap at intervals 

 of 1, 2, and 12 hours, respectively. A marked increase in the average 

 number of eggs per female was found in these samples, as follows: 

 21.3 after 1 hour, 22.3 after 2 hours, and 19.7 after 12 hours. Crowding 

 of the beetles in the glass jar attached to the trap apparently causes 

 females to deposit most of their mature eggs. 



* The writers wish to acknowledge the work of C. W. Kearns, field aid at the Tobacco Insect Laboratory 

 during the summers of 1932 and 1933, in developing this method. 



