THE BOLL- WEEVIL PROBLEM 13 



HIBERNATION. 



As has bepn pointed out, the boll weevil passes the winter in the 

 adult stage. In the fall when frosts occur, immature stages ma}- ho 

 fomid in the squares or bolls. Provided the food supply is sufficient, 

 many of these immature stages continue their development at a very 

 slow rate, and adults finally emerge. Thus there may be a somewhat 

 contmuous production of adults during the winter. Ordinarily, how- 

 ever, tliis is not the case, since the frosts that destroy the cotton 

 generally Idll practically all of the immature stages of the weevil. 



With the advent of cool weather in the fall the adult boU weevils 

 in cotton fields begin to seek protection against the winter. They fly 

 from the fields in every direction, although their movements are gov- 

 erned partially by the prevailing winds. They may fly into hedges, 

 woods, cornfields, haystacks, farm buildings, or other places. Speci- 

 mens have been found in such situations, and also in considerable 

 numbers in Spanish moss growing some distance above the ground 

 on trees. A number of weevils also obtain hibernating quarters 

 without leaving the cotton fields. These may crawl into cracks in 

 the ground, under grass, weeds, and other trash, and into the burrs 

 from which the cotton has been picked. In some cases several thou- 

 sand weevils per acre have been fomid hibernating in such situations. 

 Here, however, the mortality is greater than where the protection is 

 better. In fact, hibernation in the fields is not of great importance 

 except in southern localities. That the majority of weevils that hiber- 

 nate successfully do not pass the winter in the cotton fields has 

 been showTi by many experimental observations and is demonstrated 

 every year in the infested territory by the appearance of the first 

 damage in the immediate vicinity of woods and in other places where 

 conditions for protection are favorable. 



During the winter the weevils take no food and remain practically 

 dormant. On especially warm days they may move about to a cer- 

 tain extent. During the very mild winter of 1906-7 hibernatmg 

 weevils were found moving about more or less throughout the neriod 

 from November to March. 



The number of weevils hibernating successfully has been deter- 

 mined very accurately for different conditions. It varies with the 

 temperature of the winter and with the region. Heavily timbered 

 regions, especially where Spanish moss occurs, show the smallest 

 winter mortality. In Louisiana, out of 25,000 weevils, 2.82 per cent 

 survived the winter of 1905-6. These weevils were placed in a variety 

 of conditions that must have approached those which weevils must 

 encounter naturally. The winter referred to was practically a normal 

 one so far as temperature and precipitation were concerned. In 

 extensive work in Texas during the winter of 1906-7, out of 75,000 



