Dispersión espacial de larvas postalimentarias de moscas de importancia forense: implicaciones para la investigación médico-legal

Introduction

Calliphoridae flies allow estimating the post-mortem interval, as they are the first to arrive at a decomposing body. Its larvae feed on the carcass and then move away to pupate (post-feeding dispersal). Since the environment alters the physiology and behavior of insects, the dispersal of larvae and the final location of pupae could be related to the place where the carcass is deposited. The aim of this work was to study the dispersal of post-feeding larvae in relation to environmental variables in northern Patagonia.

Materials and methods

The distribution of pupae in response to different illumination, temperature and soil inclination conditions was evaluated. A circular box divided into quadrants was used for each treatment and a control. Post-feeding larvae were placed in the center of each box, allowing them to disperse until they pupate. Differences in the number of pupae collected in each quadrant were evaluated by X² tests.

Results

According to the control, the dispersion of post-feeding larvae occurs randomly (p = 0.098). Regarding temperature, the larvae eluded the heat source (p < 0.01). The inclination treatments showed that larvae avoided the raised surface (p < 0.01). Concerning illumination conditions, no trend was observed (p = 0.41).

Conclusions

Knowing the dispersal patterns of larvae, considering environmental variables, reduces search times and let infers the sectors with the highest probability of finding pupae. In this way, it is likely to estimate a more precise post-mortem interval in the framework of medico-legal investigations.