METHODOLOGY

1. THE EFFECT OF ESCOPOLAMINE BROMIDE ON LARVAL DEVELOPMENT AND THE DETECTION OF THE DRUG IN THE LARVAE, PUPAE AND ADULTS OF Chrysomya megacephala (F.) (DIPTERA: CALLIPHORIDAE), Arício Xavier Linhares1 & Helena Gutierrez Oliveira2 1.Department of Parasitology, Campinas State University (UNICAMP), Brazil; 2. Department of Zoology, UNESP Rio Claro, Brazil INTRODUCTION The presence of drugs in the tissues of a corpse may affect the development of the larvae of necrophagous flies Introna et al., 1990; Nolte et al., 1992; Gagliano-Candela & Aventaggiato, 2001; Pien et al., 2004).. This had already been observed for several drugs such as heroine, cocaine,paracetamol, amphetamines, phenobarbital, benzodiazepines, among others. (Goff et al.,, 1989, Nolte et al., 1992, Carvalho et al, (2001). This may cause an error in the Post Mortem Inyerval (PMI) estimate. In this work, we dewtermined the effects of Escopolamine on the larvae of Chrysomya megacephala, a drug that causes depression of the central nervous system, and that is widely used for severe pain and muscular cramps A METHODOLOGY A colony of Chrysomya megacephala was establisehd in the lab, and the F2 generation was used in the experiments. The larvae were placed in glass vials containing 200 ml of an artificial rearing diet made of Water, casein, brewer’s yeast, powdered milk, agar and nipagin (Leal et al., 1982). In addition to the control group, four experimental groupos were used, containing the following concentrations of escopolamine bromide: The mean lethal dose (X) (1270 mg of scopolamine bromide/kg of diet, corresponding to the oral mean lethal dose for rats), half the mean lethal dose (X/2), 1/4 the mean lethal dose (X/4), and two times the lethal dose (2X). For each treatment group 400 larvae were used, andthree replicates were done for each treatment. Weights and lengths were individually recorded for groups of 10 larvae at 6 hour intervals up to the end of the larval stage or until they all died. One way ANOVAs were performed to compare the effect of the treatments on the development of the larvae (weight and length), and to compare de effect of the treatments on the larval development by time. The analyses were done using the statistical package SAS (SAS, Inc. 1987). B Figure 1. The effect of different concentrations of Escopolamine on the larval development of Chrysomya megacephala trhough time, as measured by weight (A) and lenght (B). C= Control; X4= one fourth the lethal dose; X2= half the lethal dose; X the lethal dose; 2X= twice the lethal dose. RESULTS AND CONCLUSION There was a significant effect of the drug concentration on larval development as measured by weight (F= 65.92; p<0.0001) and length (F= 83.86; p< 0.0001).The larvae reared in the diet containing the mean lethal (X) and the X/2dosesshowed a significant reduction in developmental time when compared to Control and X/4 groups, and all larvae reared in the diet with 2Xthemean lethalconcentration died within 24 hours after hatching. Larvae reared at the X/4concentration showed no significant difference to the Control group. The results evidence that, depending on the concentration, the presence of this drug significantly affects the larval development, and may lead to errors in estimating the postmorteminterval. REFERENCES Carvalho, L.M.L., Linhares, A.X., Trigo, J.R. 2001. “Determination of drug levels and the effect of diazepam on the growth of necrophagous flies of forensic importance in southeastern Brazil,” Forensic Sci. Int. 120: 140-144. Gagliano-Candela, R., Aventaggiato, L. 2001. “The detection of toxic substances in entomological specimens.” Int. J. Legal Med. 114:197–203. Goff, M.L., Omori, AI., Goodbrod, J.R. 1989. “Effect of cocaine in tissues on the development rate of Boetcherisca peregrina (Diptera: Sarcophagidae),” J. Med. Entomology 26: 9 1-93. Introna, F., Lo Dico, C., Caplan, Y.H., Smialek, J.E. 1990. “Opiate analysis in cadaveric blowfly larvae as an indicator of narcotic intoxication.” J. Forensic Sci. 35:118–122. Nolte, K.B., Pinder, R.D., Lord, W.D. 1992. “Insect larvae used to detect cocaine poisoning in a decomposed body,” J. Forensic Sci. 37: 1179-1185. Pien, K., Laloup, M., Pipeleers-Marichal, M., Grootaert, P., Boeck, G.D., Samyn, N., Boonen, T., Vits, K., Wood, M. 2004. “Toxicological data and growth characteristics of single post-feeding larvae and puparia of Calliphora vicina (Diptera: Calliphoridae) obtained from a controlled nordiazepam study.” Int. J. Legal Med. 118: 190-193. SAS Inc., 1988. SAS/STAT User’s Guide: Release 6.03 Edition. Cary, NC, 1028 pp. Work supported by FAPESP, grants #05/50098-0, and # 2004/08544-0