CSI Special Insects Unit Forensic Entomology

Here's a fascinating niche science that, if you ask me, we should see on prime-time TV way more often: forensic entomology, the study of insects and arthropods used in legal investigations. As it turns out, there are lots of cool ways insects can help us solve crimes. Fair warning, though: you may not want to watch this one over lunch! [Music/intro] The field of forensic entomology is
actually pretty broad and is commonly divided up into three general areas: urban, stored product, and medico-legal. The urban specialty focuses on insects in human dwellings.

Scientists who do this kind of work
could surely tell you all kinds of amazing things about what goes on in
your kitchen cabinets at night, but as forensic experts, they specialize in
investigating both civil and criminal cases helping in lawsuits involving, say, damages from a cockroach or bed bug infestation. Stored product entomology, meanwhile, usually deals with the contamination of commercial products, like if you find a
family of dead ants in your fast food burrito, or a bunch of moth wings in your candy bar, or spiders in your toilet paper roll. But
the medico-legal area is the most flashy, popularized part of the field. It's what you might see on an episode of CSI and it often involves reading the signs of blood sucking or carrion-feeding
insects at violent crime scenes typically involving murder, suicide, abuse, and neglect.

At a fresh crime scene, for example, forensic entomologist would know that tiny flecks of what look like spattered blood could actually be the prints of roaches
or flies that had walked through blood elsewhere at the scene. These experts can even match human DNA from the blood found in blood feeding insects, living or dead. One murder case in Italy was solved when investigators scraped a blood filled mosquito off the wall in a
suspect's house and found it contained the blood of the victim. Take that, bad guys!  Crime-solving, bug-loving scientists are also often called upon to help estimate a victim's time of death.

A dead body goes through a whole series of phases from putrefaction and
fermentation to dry decay and skeletonization, and each phase attracts different life
stages and types of insects. Forensic entomologists use this rotating cast of critters to help determine a body's death in a couple of ways usually involving larval development and species succession. The larval development technique studies the size and
prevalence of maggots and other larva and is usually useful if the body is less
than a month old.  If the corpse is older, it's best to use the species succession
method.

For example, blow flies are great quickly discovering dead meat because they like their food fresh and full of fluids, so determining what phase they're in can often provide the most accurate estimates for time of death, but as the flesh dries out the blow flies
take off just as other species like the coffin fly arrive in force. Once the corpse is too dry for even
maggots, all the flies clear out. Then beetles often roll in. Some species like hide and carrion beetles have robust mouth parts they can work on the remaining
dried flesh and ligaments.

Mites and moth larvae round out the final cleaning crew, consuming the remaining hair and leaving only a skeleton.  So thanks to all the insects out there and
the scientists who study them for solving crimes and doing a job I would rather not do!  And thanks for
watching this SciShow Dose especially to all of our subscribers on Subbable who make this whole channel possible.  Did you know that you can be an honorary associate
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