REARING INSECTS
A significant step in identifying immature insects, especially flies, is the rearing of larvae into adult insects. This process is not as easy as it may initially sound. Because these immature insects are the reference materials for the forensic entomologist’s estimation of PMI, their growth environments (temperature, humidity, space, light, etc.) must be closely controlled and monitored. A vent hood is a necessity: Because their food source is rotting meat (typically beef, pork, or liver), the smell can become unpleasant. Depending on how many cases the entomologist works on at one time, the rearing laboratory must be able to keep all the samples and insects separate. It is important to remember that fly larvae grow into adult flies, and they must be kept from zipping across the laboratory! And, finally, the laboratory must be designed so that it is easy to clean after the case work is completed. Specially devised chambers for insect rearing can be purchased, but they are very expensive. Many entomology laboratories use large aquariums, disposable containers (often, pint-sized ice cream or plastic containers with holes punched in the lid for ventilation), and pie tins as inexpensive but effective larval growth chambers. Some insects require special conditions for growth that mimic the phase of decomposition that the insects recognize as appealing, such as dermestid beetles, which colonize remains only after they have become dry and desiccated.
FIGURE 1 Insects commonly found on or near dead bodies. (a) Springtail, (b) Rove Beetle, (c) Housefly, (d) Carrion Beetle, (e) Blow Fly (blue), (f) Cockroach (American), (g) Assassin bug (Hemiptera, Reduviidae), (h) Hymenopter (Hymenoptera).
