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Michael Aranda walks you through the crime-fighting science of forensic entomology, the study of insects used in criminal investigations. As if you needed more reasons to love bugs. But be warned: You might not want to watch this during lunch.
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Here is 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.


 Forensic entomology

The field of forensic entomology is actually pretty broad, and it's 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 often involves reading the signs of blood sucking or carrying feeding insects at violent crime scenes, typically involving murder, suicide, abuse, and neglect.

 Solving crimes

At a fresh crime scene, for example, forensic entomologists would know that tiny flecks of what looks like spattered blood could actually be the prints of roaches or flies that walk 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 techniques study 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, blowflies are great at 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 blowflies take off just as other species, such as 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 that can work on the remaining dried flesh and ligaments. Mites and moth larvae round out the final cleaning crew, consuming 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.


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