Entomological evidence collection

There are commercially available insect evidence collection kits [1], but you can customize your own to meet geographical and budget requirements.

[1] In order for entomological evidence to be of value for a death scene investigation it is important that every detail be noted and preserved.

Great care must be exercised when collecting insects to ensure that morphological characteristics are kept intact for positive species identification.

[2] In most cases, it is important to collect samples for the study of insect succession three times a day for about a month.

Insects may only be removed from the surface of the body, and great care must be taken with forceps and other tool to prevent postmortem artifacts.

Eggs are generally laid in clumps or masses, and are found in any orifice whether it be a natural opening or a wound.

In order to prevent the eggs from dehydrating it is important to place a damp tissue or other media in the collection vial.

It also important to make sure the eggs have air, placing a paper towel over the top using a rubber band provides plenty of ventilation.

As mentioned earlier it is important to note the maggot mass location and temperature, because this will influence the degree days it takes for the fly to develop.

A sample of living specimens approximately 100 of each size or distinguishable species, should be kept in a maggot rearing container.

One other insect that is forensically important is the beetle, known to provide clues to the degree of exposure the body has experienced.

[6] This technique was developed in Knoxville, Tennessee in 1989, and in the pilot study was found to be more effective than using an aerial net.

[2] Generally insects associated with carrion are strong and fast fliers, but with practice can be caught using an aerial net.

This procedure should be repeated approximately 3 times to ensure a good sample of flying insects in the area.

This is why it is important to take soil samples directly under the body so as to recover these insects that might be hidden from plain sight.

These stages can be in the form of eggs, larva (of which the largest instars are the most important for identification) pupa and adults.

The use of the recordings from the forensic entomologist of the death scene temperatures and the NWS station combined will increase the accuracy of the post mortem interval.

[2] Use of the death scene case study form assists in documenting the immediate area of where the body was discovered.

While analyzing the area the method of concentric circles is utilized in order to ensure evidence is not overlooked.

While walking in these circles, it is important to note major infestations of the insects in an area of twenty feet of where the body was located.

With the presence of an entomologist at the scene, evidence such as this can be correctly identified instead of investigators inaccurately determining the body was dragged across the ground.

[7] The death scene case study form includes recording whether the area is rural, urban, or aquatic.

In November 1995, a female heroin addict committed suicide by placing her neck across a rail road track of a moving train.

Based on the development of these flies, a postmortem interval was calculated and the body was believed to be at the site for 112 to 128 days.

Although the head was moderately mummified, the skin on the face, soft tissue of the eyes, lower jaw, ears, and tongue was absent.

Protophomia terraenovae are the most frequent species associated with people in the area of the scene and are known to have a life cycle within nineteen to twenty-three days.

Lastly, as seen in photographs taken at the scene, flies were seen to be in beginning development stages, signifying that the person died inside then taken outside.

This is not abnormal that a heroin addict dies and is ignored within friends, as he is believed to be sleeping or on a bad drug trip.

[11] An advancement that has recently been made is due to the development of techniques such as the polymerase chain reaction, PCR, to identify remains.

Researchers have been able to isolate the gut content of insects found on bodies and use techniques similar to PCR to recover mitochondrial DNA.