behavioral or locomotory patterns. While the short-term effects on 
development of two species of Decapoda are described in this paper, nothing is 
known of the way in which long-term exposure to sublethal concentrations 
through a number of successive generations may contribute to mutagenic 
effects. Within the realm of the chemistry of these compounds, a number of 
questions also remain unanswered. Several authors have described the rate at 
which insect growth regulators degenerate within certain natural and artificial 
environments (16, 18) but none of these studies have investigated the 
degradation rate in either an estuarine or a marine environment. Most of the 
research which has been conducted thus far has concentrated on the effects of 
the intact compound, and no data appear to be available on either the 
breakdown products which may occur under estuarine conditions, their fate in 
the natural marine environment, or the way in which they may affect 
developmental processes of marine invertebrate animals. 
Although it is clear that the juvenile hormone mimics and insect growth 
regulators may offer great potential as replacements for many of the more 
persistent pesticides, it seems equally clear that a considerable amount of 
research remains to be done to assure their proper use within the estuarine and 
coastal environments. 
ACKNOWLEDGMENTS 
We are grateful to Zoecon Corporation, Palo Alto, California, for providing 
the pure compound methoprene (Altosid R ) and to the Monsanto Corporation, 
St. Louis, Missouri, for supplying MONO-585 for experimental use. This 
research was supported by a grant (R-803838-01-0) from the Environmental 
Protection Agency. 
REFERENCES 
1. Christiansen, M.E., J.D. Costlow, Jr. and R.J. Monroe. 1977a. Effects of 
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of the Mud-Crab Rhithropanopeus harrisii in Various Salinities and Cyclic 
Temperatures. Mar. Biol., 39:269-279. 
2. Christiansen, M.E., J.D. Costlow, Jr. and R.J. Monroe. 1977b. Effects of 
the Juvenile Hormone Mimic ZR-512 (Altozar R ) on Larval Development of 
the Mud-Crab Rhithropanopeus harrisii at Various Cyclic Temperatures. 
Mar. Biol. 39:281-288. 
3. Costlow, J.D., Jr. 1967. The Effect of Salinity and Temperature on 
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