172 



creared percentages of alcohols (and thereby decreased percentages of alde- 

 hydes) significantly improved performance. One alcohol was more important 

 than thi' other in determining activity, but both alcohols must be present 

 with small amounts of the aldehydes for maximum ef fectiv:;ness. Captures of 

 boll weevils increased only slightly when doses were increased above 3 rag. 



331. ; Mitchell, E. B.; and Huddleston, P. M. 1966. Chemoreception of 

 attractarits from the cotton plant by boll weevils, Anthonomus grand is 

 (Coleoptera: Curculionidae) . Ann. Entomol. Soc. Am. 59: 867-868. 



We obtained a significant difference in mean percentage of weevils responding 

 following several treatments, compared with untreated weevils, but we noted a 

 significant difference in mean ratio (attractant: control) only when 1 or both 

 antennal clubs were removed or painted. When results from similar treatments 

 were combined, a significantly greater response was obtained by removing or 

 painting only 1 antennal club than by removing or painting both clubs. Our 

 results, and the frequent behavioral action of boll weevils "cleaning" their 

 antennal clubs with their front tarsi when they are responding to attractants 

 strongly suggest that the organs of boll weevils that receive olfactory 

 stimuli are situated in the club of the antenna. No differences in response 

 attributable to sex were detected. 



332. ; Mitchell, E. B.; and Huddleston, P. M. 1966. Effect of age, 

 nutrition, sex, and time of day on response of boll weevils to 

 an attractant from cotton. Ann. Entomol. Soc. Am. 59: 1024-1025. 



We concluded that in the continuing bioassay of plant attractants for boll 

 weevils, unsexed weevils, A-5 daya old, fed on 10% sucrose-water solutions 

 before testing will give the most reliable results for tests made at any 

 time during the day. This procedure is now being used at this laboratory 

 to bioassay attractant fractions provided by chemists. 



