Fluoxetine effect on life cycle and some morphological parameters of Dermestes maculatus (Coleoptera: Dermestidae)

Abstract

The study of cadaveric insects for detecting xenobiotics in a qualitative and quantitative way is called forensic entomotoxicology. It also studies how xenobiotics can affect insect development. Generally, antidepressants are the most chemical agents used in suicide. In a previous study was determinate and quantified fluoxetine (selective inhibitor serotonine recapture, SSRI) in Dermestes maculatus (Coleoptera: Dermestidae), an insect of forensic interest. In this study was evaluated the effect of fluoxetine on D. maculatus development. For that, adults of this species were put inside plastic containers and fed with a mixture of pig muscle and fluoxetine (treatment) considering a 2000 mg/kg concentration to emulate lethal overdose for humans and animals. As control were used beetles fed only with pig muscle. The containers were maintained in an incubator at 30°C±1°C, 55.4% relative humidity and 12:12 h Light:Dark photoperiod. Observations and quantifications were performed diary from the beginning until ending life cycle of beetles. Larvae of each instar, pupae and adults were collected to register total body length, and in the case of larvae, were also registered cephalic width and weight. Durations of each larval instar, each stage of development and total cycle were registered. Two replicates were performed. Larval mortality was not affected by treatment, no differences were found between control and treatment. It was not found a notorious and systematic difference in the duration of egg stage that suggested a treatment effect. From larval instar 2 to larval instar 5 (L2-L5) was observed a systematic reduction of larval instar duration due to treatment. The durations of the larval stage and pupal stage were slightly short in treatment than in control. The total duration of the life cycle was almost the same in the treatment and control. When larval weight was analyzed it was not observed a systematic difference between control and treatment but was observed a systematic increase in larval length due to treatment. With respect to cephalic width, it could not be discarded an effect of treatment and if this is the case, the cephalic width would be major particularly in the last instars. The results would suggest that fluoxetine could produce alterations on D. maculatus development, in duration and some morphological aspects, although the total duration of the life cycle would not be altered. Because the results are based in two replicates or trials, the results will be verified with a third replicate that is being performed.