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Section 2. Effects of Relative Humidity on Snail Activity 



Introduction 



No information has been reported on the effect of environmental 

 conditions on the citrus tree snail's movement. Therefore, studies 

 were conducted to obtain information on the relationship of snail ac- 

 tivity and relative humidity. This information is necessary to de- 

 termine if relative humidity is a limiting factor in snail activity. 

 If snail activity is directly dependent on relative humidity, it would 

 be possible to monitor for periods favorable for the snail and to deter- 

 mine the hours of snail activity. 

 Materials and Methods 



A naturally occurring population of the citrus tree 

 snail, D. dormani was located within a grove in Orange Lake, Florida. 

 The grove was unsprayed and was maintained with a cover crop or ground 

 cover. It was observed that the snails were generally active at night 

 or during heavy rains. Twenty snails were located to determine the 

 snail activity and relationship to relative humidity. Ten quiescent 

 snails on each of two adjacent trees were located and marked on the 



D 



dorsum of the shell with an identification number using Day-glow paint. 



Application was made with a one milliliter tuberculin syringe. A 



spring type clothespin was placed adjacent to each snail and was marked 

 with the same number as the snail. 



A battery operated ultraviolet lamp, model U.L.V.-56, illuminated 



p 

 the Day-glow pigment which facilitated locating the snails at night. 



Relative humidity, time, and percent snail activity (percent of snails 

 active per unit time) were recorded every half hour from 9:00 p.m. un- 

 til! 8:00 a.m. The experiments were terminated at 8:00 a.m. because 



