Hold The Maggots Please

By Dusana Bondy, Dipl EPM
Technical Support Auditor - Abell Pest Control

Where are all these flies coming from or what about the medium sized black beetles with the white stripe across their back? If you as a tech, homeowner or plant manager have ever had to ask this question, looking towards the foundations of Forensic Entomology maybe the answer.

The true meaning of Forensic Entomology is the study of insects associated with a human corpse in an effort to determine elapsed time since death or other details of murder. Recently I had the privilege to hear Dr. Gail Anderson speak on this extremely interesting if not slightly gruesome topic. Dr. Anderson has been analyzing forensic entomology cases since 1988, and has often testified as an expert witness in court. You may already be familiar with her work, as she has been featured in several television programs. With that being said, we now move onto its relation in the Pest Control Industry. Not with human corpses, but rather with decomposing, mummified rodents or dead Cluster flies within a structure.

Its always a good idea to keep in mind, some insects are not only themselves pests, they are also indicators of other pests present within a structure. Secondary Pest Infestations often occur within a building and knowing the life cycle of both pests involved is crucial for control.

Those green, blue or purple metallic Blow Flies seen buzzing around inside an establishment are likely associated with a recently dead rodent or bird carcass inside the walls, ceiling void or heating system. Flies move in quickly and can skeletonize an animal in days. Adults lay their eggs on liquid protein; larva feed on liquid, blood and mucus, pupae seek drier areas to complete their life cycle and as adults emerge again they seek food and areas to lay eggs. Different temperatures will affect the rate at which flies will breakdown a carcass. If say for instance a mouse is dead in a cool area of a house in mid winter, that same mouse may be subject to infestations come summer time and warmer temperatures. Longer-term presence of dead rodent carcasses or accumulations of Cluster flies in attics and wall voids are perfect breeding sites for Dermestid Beetles. Dermestid Beetles include: Larder Beetles, Warehouse Beetles and Carpet Beetles.

Dermestid Beetles and their larvae feed on a variety of foodstuffs, yet a tasty meal of dead Cluster Flies is most appetizing. Control is achieved by removing the source, however if in the walls, creating a barrier with a residual dust or liquid insecticide may prove highly effective. Ultimately if a live infestation of mice or cluster flies exists, trapping is a more effective means of control. Mechanical traps, snap traps and glue boards for mice in accessible areas can be utilized. Rodenticide use for mice may get quick results, however mice or rats may die in the walls causing additional infestations. Cluster flies can be trapped in attics by using glue board fly lights that will attract the adults. Eliminating the possibility of a secondary infestation will prevent future aggravation for the homeowner.

Now hopefully, when these pests appear, one can take on the role of a Forensic Entomologist, seek out the source more easily, and solve the problem efficiently and quickly without the need for calling the police!