compare crime
scene temperatures to official Environment Canada records for the same times. The
statistical comparison, and appropriate adjustments if necessary, will facilitate a
retrospective capture of crime scene temperature data. In conjunction with known
biological information about the species of blow flies recovered from the victim's
remains, I will be able to track back to the time when blow flies first colonised the
corpse. Depending on environmental conditions, this time is often consistent with time of
death. Such an insect investigation into decomposing remains will help the Coroners Office
determine time of death when other scientific methods no longer apply.
Claim investigation
Hold it, this is an article about bugs on bodies and establishing
time of death? What does this have to do with insurance? Consider the following example of
an insurance claim where insects come into the picture - a case of insect infestation of
foodstuffs (the names and places have been changed to protect parties). Using similar
analytical techniques as above it was possible to determine the timing of an outbreak of
Indian meal moth in a company work plant and, hence, the origin of insect infestation in a
food product. Snack-A-Rooney Inc. processes raw materials, including dried fruits nuts and
grains into a health food treat marketed worldwide. Raw materials are received into the
plant from several different suppliers, processed and packaged into product within a three
to five day period, stored for up to three months, whereupon it is shipped to customers.
Disaster strikes
One fall day, Snack-A-Rooney's CEO John Greeves, is called by a
Florida customer. The customer claims the snacks, wrapping intact, were being returned
because "worms" could be seen through the transparent cellophane packaging.
Snack-A-Rooney is suddenly flooded with calls and product returns. |
The company is
further plagued by an outbreak of moths at its plant. Greeves alerts his insurance broker
who sets in motion a claim. A claims adjuster is called in to investigate the claim,
following which I was brought into the picture. I visit the scene and take samples of the
infested and still wrapped product as well as "clean samples". I note that the
returned product originated from the same lot number dating back three and a half months
earlier. I also discover that the company's current moth outbreak is one of a series and
get the quality control people to dig out the dates. During a tour of the facilities, I
observe that the adult moths stuck to the sticky traps are indeed Indian meal moths.
"What kind of climate control do you have in here?" I inquire. Silence. The
quality control people exchange worried glances. "Actually, there hasn't been, it's
been turned off since spring. It's pretty well the same as it is outside this time of
year", is the somewhat hesitant reply. They observe while I pencil in yet another
item into my notebook.
Temperature data
Fortunately for Snack-A-Rooney there is an Environment Canada
weather station close by. I expect the temperatures for both places to be comparable with
minor variations in microclimate. I later procure the weather records through the claims
adjuster. Could there be a direct relationship between the timing of the arrival of
infested skids from suppliers into Snack-A-Rooney's plant late spring and the subsequent
moth outbreaks? Or, could the origin of infestation be explained through local means? The
Indian meal moth is a common insect – could moths have flown into the plant from
outdoors? Alternatively, could they have originated from within the plant itself? The
possibility that a hefty amount of product had been simultaneously infested at retail
outlets globally was eliminated after minute examination of the packaging. The packaging
was intact and there were no means of entrance by adult or larval moths. |
Insects and
temperature
There are linear relationships between the development of most
insects and temperature. There are also minimum temperatures below which development of
the insect is suspended. The relationships vary between insect species, but this rule
generally applies, and the Indian meal moth is no exception. Literature research is now
critical. Without specific information on the temperature dynamics of the Indian meal moth
with respect to its developmental rate, any conclusions I may later draw will not suffer
scrutiny by litigation experts, should push come to shove.
Forensic entomology methodology is steeped in decades of research
through the agricultural and forestry industries. I am not disappointed by what I find.
The amazing part of the methodology in this case is that relative humidity played a
quantitative role in the analyses, whereas it does not in criminal cases using maggots.
Fly larvae feeding on decomposing remains are almost totally immersed in a semi-fluid,
then fluid medium. Humidity, therefore, does not matter to them. It matters to the eggs,
in a qualitative sense, in that they need humidity in order to hatch and for young larvae
to subsequently establish in their food substrate.
Indian meal moth larvae (caterpillars), colonise dried foodstuffs. The
caterpillars are soft-bodied, with the exception of the head capsule, and naked. Relative
humidity and moisture of their food substrate is therefore quantitatively relevant to
their survival and growth. Development at 22ºC, for instance, takes 24% longer at a
relative humidity of 43% compared with a level of 70%.
Laying the cards down
My job as a forensic entomologist is to examine the pieces of the
puzzle as simply and objectively as possible. This meant that Snack-A-Rooney Inc. had to
lay all the cards on the table. Little did they know when they
  |