zoology biology benno meyer rochow science blog forensic entomology

The Insect Crown Witness

Crucial testimony without words

Many years ago I spent several highly enjoyable and educational months on the Trobriand Islands (nowadays also referred to as Kiriwina Islands) off the coast of the south-eastern end of Papua New Guinea. The islands became famous, because of Bronislaw Malinowski’s 1929 ethnographic book “The Sexual Life of Savages in North-Western Melanesia”. Local residents over there display a considerable knowledge concerning insects and their lives and on several, occasions I was warned not to drink from this or that stream because a particular insect had been sighted on or near the water, indicating a poor status of the water’s drinkability. I was also warned not to proceed any further into the jungle, when a particular species of fly was spotted that occurred when an animal corpse was somewhere nearby.

The Trobriand Islanders, in fact, use an insect as a “living thermometer”: the head louse. If children’s heads during frequent daily delousing sessions are found to harbour head lice, it is taken as a good sign: the children are healthy. Are no lice to be found, the parents will get worried. The livelihood of a louse depends on its host‘s state of health and should the host develop a temperature or suffer from hypothermia the louse is the first one to know, sensing temperature fluctuations as little as 0.3°C. As reliable health-indicators lice are even deliberately placed on the heads of infants. By the way, after only one week of staying in their hut with my native Trobriand Island friends, I was already judged to be perfectly healthy.

Customs officials, in conjunction with the police and entomologists, too, have successfully used insects as indicators (although not necessarily the louse), for example to determine the precise geographical origin of certain goods, including cannabis. And for forensic scientists insects may hold invaluable clues to solve a crime, the case of a headless woman found in gorse and bracken in England during a summer years ago, being just one case in point. A pathologist’s estimation of the time of death had been 7-10 days ago, but the total absence of blowfly larvae in combination with the presence of full-grown larvae and pupae of a separate species of fly (Ophyra sp.) suggested that the body had been kept elsewhere, possibly indoors in a warm and dry place. When the head of that poor female victim was found, it contained blowfly pupae and some maggots, but only one was identified as an Ophyra sp. This proved that the head had received a very different treatment from the body. Later confessions by the murderer revealed that the body of the woman had been kept in a sauna room for five months and that the severed head had been kept in the boot of his car. Tried and convicted on the evidence of some humble flies, the murderer had and still has ample time to ponder about the virtue of righteousness and justice.

And how does one study the succession of flies and other insects associated with human deaths? Well, there is, for example, the famous Tennessee “Body Farm” (and now also one in Australia), where corpses of people who had made their bodies available to science are placed out in the open, half buried in the soil or water, covered by leaves, clothed or naked and then have their colonization by insects monitored: over days, weeks and even many months and years. It is, of course, important to possess such detailed information, but whether people who donated their bodies to scientific research expected that kind of research to be done with them when no longer alive, I cannot answer.

© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2018.
Unauthorized use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to V.B Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com with appropriate and specific direction to the original content.

One thought on “The Insect Crown Witness

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s