LONGEVITY OF WEEVILS AFTEK EMERGENCE. 85 



These facts indicate that the records for Calvert and Victoria are 

 probably considerably below the normal survival period for emerged 

 weevils in the field, and the records for Dallas are at least conserva- 

 tive. The difference in duration of life between the males and 

 females was but slight, but rather uniformly in favor of the males. 

 In each locality the maximum longevity was shoMai by males. This 

 fact agrees with previous conclusions regarding the relative duration 

 of life of the two sexes. Apparently copulation does not materially 

 affect the longevity of either sex. In this connection it may be 

 stated that unquestionable instances of mating were found among 

 weevils immediately after their emergence and before there was any 

 possibihty of their having fed. This was of rare occurrence, and the 

 question of fertility resulting was not positivejly determined. 



From the records it becomes evident that many emerged weevils 

 may survive from six to twelve weeks without food and that the 

 average survival for all weevils may be between one and two weeks. 



There is some evidence to show that it is possible for these unfed 

 weevils to move rather extensively in search of food, and undoubtedly 

 this is done in many instances. Other observations, however, indi- 

 cate that if food is not found in the vicinity of emergence the weevils 

 may become quiet for a considerable period before again seeking food, 

 and in this way their movement may occur only through compara- 

 tively short distances. It is also probable that when they first find 

 a food supply they do not intentionally leave it in search of other 

 plants which may be in a more advanced stage of growth. 



As to the proportion of each sex among the weevils surviving in 

 these experiments it appears that 57 per cent were males. The maxi- 

 mum longevity of any weevil was ninety days. Tliis was a male 

 which was kept under outdoor conditions from March 1, when it 

 emerged, to May 30, when it died. The maximum life for a female 

 was eighty-eight days. Tliis weevil emerged April 25 and died July 

 20. The average temperature under which tliis lot of weevils was 

 kept ranged between 45 and 60 degrees and the average length of life 

 for all of the 55 weevils tested in series 17 at Dallas was slightly more 

 than tliirty days. Tliis emphasized the important effect of tempera- 

 ture upon the period of survival without food. 



The grand total for average duration of life shows 10.1 days for 

 more than 4,600 weevils. The males lived on an average one-half 

 day longer than did the females. 



It would be both interesting and valuable if the records showing a 

 summary of the results for each sex in each series of experiments 

 could be presented in full. It is thought, however, that the corre- 

 sponding records for the fed weevils have a greater value and it may 

 be allowable to present in place of the full records for the unfed 

 weevils merely a brief statement of the most important facts as to 

 the survival of each sex. 



