26 



relative humidity or saturation for initiation of snail activity. In 

 each of the three observations over the three years, 100% relative hu- 

 midity was obtained before the initiation of any significant snail ac- 

 tivity. The July 18, 1977, observation resulted in a snail line slope 

 of M=3. The resulting line slope of the percent relative humidity was 

 M=0 until 3:30 a.m. when it began increasing. Saturation was reached 

 at 3:45 a.m. The slope formed from 96% to 100% relative humidity was 

 M=3, the same as with the snail activity line slope. Again the correla- 

 tion of the slopes was demonstrated. 



The problem with locating the snails during light hours made snail 

 activity determination extremely difficult. For this reason no attempt 

 was made to determine the relationship of the termination of snail ac- 

 tivity with a decreasing relative humidity. Smith, 1976 , (unpublished 

 data) was able to demonstrate a rapid decline in snail activity when 

 the relative humidity fell below 100%, again supporting the need for 

 100% relative humidity for activity. 



The citrus tree snails were determined to be active only during 

 periods of 100% relative humidity. This was demonstrated in all three re- 

 plicates. D. do rmani , which is dependent on water, has evolved to an 

 arboreal habitat and utilized available water sources found during 100% 

 relative humidity. Locomotion is believed limited to this condition 

 due to excessive pedal secretions used to maintain adhesion to the sur- 

 face. If sufficient water was not present the snail would quickly 

 desiccate. During showers the snails have been observed to be active 

 throughout the day. This would suggest the dependence of the snail on 



Smith, B. 1976. Graduate Student. Department of Entomology and 

 and Nematology, I.F.A.S., (University of Florida). 



