SECOND GENERATION PESTICIDES 

 AND CRAB DEVELOPMENT 



John D. Costlow and C. G. Bookhout 



Duke University Marine Laboratory 



Beaufort, North Carolina 28516 



ABSTRACT 



A number of compounds have been introduced recently as potential 

 substitutes for the traditional "hard" pesticides in the control of insect 

 populations. Some of these compounds, juvenile hormone inimics or analogs, 

 are intended to simulate the activity of naturally occurring juvenile hormones 

 and prevent metamorphosis or. in tlie case of insect growth regulators, control 

 differentiation or specific physiological processes at specific stages of 

 development. Because of the phylogenetic relationsliip between insects and 

 crustaceans, one miglit legitimately expect that those compounds which alter 

 or interfere with the developmental pattern of insects could also have similar 

 effects on the developmental stages of marine crustaceans. 



In salinities of 20 and 35 ppt. 100 percent mortality of megalopa of C 

 sapidus occurred when exposed to 10 ppm MONO-585 while 1 ppm reduced 

 survival from 100 percent to 40 percent. 100 percent mortality in the zoeal 

 stages of R. Jiarrisii was observed with a dilution of 1 .0 ppm in reduced 

 salinities but at 20 and 35 ppt, survival was unaffected. The concentration of 

 10 ppm MONO-585 was lethal in all experimental salinities. Exposure of C 

 sapidus megalopa to 0.1 ppm Methoprene resulted in reduced survival only 

 when lower temperatures (20-25'^C) were used. Juvenile crab stages I through 

 IV were unaffected by the concentrations of Methoprene used. 



The findings of these experiments and their possible significance to normal 

 development of larvae of these two species within the natural environment are 

 considered. 



INTRODUCTION 



A number of compounds have been introduced recently as potential 

 substitutes for the traditional, "hard" pesticides (DDT, Malathion. Dieldrin, 

 etc.) in the control of insect populations. Some of these compounds, juvenile 



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