sophisticatedscientist

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Do Bugs Do Drugs?

Thirty years ago, the use of entomology in an investigation was considered bizarre, despite the firm scientific backing and historical uses- I guess people just didn’t like bugs that much! Fortunately, people are starting to come around and entomological evidence is now considered an accepted sub discipline of forensic science. Forensic entomology is still growing, and new studies are uncovering valuable information that can be useful in many realms of forensic investigation.

Since the beginning of forensic entomology flies have been at the forefront of research and discovery. An entomologist can analyze the environmental condition and compare this to the lifecycles of flies present on the body. This information can help a forensic entomologist determine the post-mortem interval (PMI). Scientists have recently discovered that drugs and poisons can affect decomposition rates by changing how the body reacts with the environment. Evidence of drugs and poisons can be found by testing the blood, urine, solid tissues, and hairs from the dead body. But what happens when all that is left is a skeleton?

A recent advancement in the field of forensic entomology has discovered that insects collected from a carcass can be ued as an alternative toxicological specimen. Scientists have discovered that poisons and toxins can be found in the exoskeleton of insects feeding on the corpse. An insect’s exoskeleton is composed of chitin, a comparable substance too keratein protein. Similarly to keratein, chitin stores drugs for a long time. Empty fly puparial cases can also be used to test for toxins, as well as skin from carrion beetles. Knowing the toxicological report from a victim’s corpse can help determine the PMI and, in some cases, piece together how a crime unfolded.

The use of insects to determine toxins and poisons in and around a corpse has some very interesting and practical applications in not only to the field of forensic entomology but also anthropology. Research on toxicological applications of insects, is currently being used to determine drug use in ancient skeletal remains. Soon, scientists and investigators will not only be able to determine if a deceased victim was drugged but also if our mummified ancestors were rocking out with a bit of cocaine on the weekend.

References

Joseph, I., Mathew, D., Sathyan, P., & Vargheese, G. (2011, July). The use of insects in forensic investigations: An overview on the scope of forensic entomology.

Mashaly, A., Ibrahim, A. Forensic entomology research in Egypt: a review article. Egypt J Forensic Sci 12, 11 (2022). https://doi.org/10.1186/s41935-022-00272-8

Paola A. Magni, Sasha C. Voss, Roberto Testi, Matteo Borrini, Ian R. Dadour, A Biological and Procedural Review of Forensically Significant Dermestes Species (Coleoptera: Dermestidae), Journal of Medical Entomology, Volume 52, Issue 5, September 2015, Pages 755–769, https://doi.org/10.1093/jme/tjv106

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Crime Solving Insects

You may be surprised to find out that police officers, firefighters and paramedics aren’t usually the first to arrive at the scene of a gruesome crime. The quickest first responders are actually…insects! As a corpse decomposes, flies are drawn to the odors produced by gases and biological fluids leaking from a corpse. The use of insects as evidence in criminal trials is called forensic entomology. You may be wondering; how did this all start? How long have we been studying bugs for evidence? Well, let me weave you a tail or rather- let Tz’u Sung tell this tale. After all, he wrote the oldest extant book on forensic medicine. In his book The Washing Away of Wrongs, he tells a tale of a 13th century murder that happened on a rice field, a local peasant was hacked to death by a hand sickle. Having no suspects or witnesses, the investigator gathered the farmworkers and got them to stand in a line and lay down their tools. When they did this, blowflies flew towards the sickle that had remnants of blood on it. Just like that, the murderer was caught and confessed to the gruesome crime. Since the 13th century the field of forensic entomology has expanded and evolved.

Forensic entomologists can study details such as the species, life cycle, and succession patterns of insects. This information can be used to determine the PMI, for my psychologically sound readers who do not spend their Friday evenings watching binge watching crime shows, the PMI is the post-mortem interval, this tells us the time elapsed since death. Pretty cool right? But wait, it doesn’t stop there! Forensic entomology can help determine not only the PMI but also the estimated place of death if the body has been moved and if the victim had been given drugs. Thanks to the advances and newly acquired knowledge of entomology, numerous people who had been wrongly convicted of crimes are finally free. This was just what happened in the case of Kirstin Blaise Lobato, who in 2001 was wrongly convicted of a heinous murder and served 16 years! She was able to walk free in 2018, thanks to entomologists who after reviewing the photographs noted a lack of insects on the deceased and thus came up with a new PMI that proved Lobato’s innocence.

The North Carolina State University is the sight of the infamous body farm, researchers are currently conducting experiments to tackle the serious issue of child abuse, they want to better understand how the bodies of children and infants break down in the environment. These researchers of course aren’t using human children, instead they are using small pigs and documenting their decomposition in various scenarios that are commonly found when a child is “disposed” of. They were wrapped in plastic bags, blankets, and buried in shallow graves. This study discovered important information such as how fast it takes for maggots to get to blanket wrapped corpse, they noted that specimens in plastic bags decomposed at a much slower rate as very few insects could get to the corpse. They also noted how the weather played a role in life cycle of various flies and thus the decomposition process. This study proved that pigs are in fact an appropriate model for humans, and that children and babies decompose more quickly that adults. This study has also helped researchers further understand the sequence of insect colonization.

Insects colonize cadavers in a predictable sequence, also known as insect succession. Four categories of insects can be found on a decomposing body i) necrophagous species, ii) Predators and parasites feeding on necrophagous species, iii) Omnivorous species including arthropods feeding on the corpse, iv) Other species such as springtails and spiders that use the corpse as a microhabitat. The first two groups are of the most important for the purpose of forensic entomology. They contain insects from the order Diptera (flies) and Coleoptera (beetles). The dominant species used in forensic entomology belong to order Diptera and are commonly referred to as blow flies, flesh flies, and house flies. These gross corpse dwellers arrive within minutes following death, the usual areas of egg laying are natural body openings and wounds. The life cycle of Diptera insects is fast, which allows them to quickly colonize cadavers, See image attached

From the life cycle attached to this post, we can see that if an entomologist finds, let’s say pupa belonging to a blow fly on the corpse, then the corpse died more than 130 hours ago. Likewise, if they find adult blow flies but no eggs then the corpse died less than 23 hours ago. There is a large array of insects that colonize cadavers, the presence of predaceous insects that eat larvae can tell us that a corpse is between 2 and 7 days old. The PMI becomes more precise with every larvae, pupa and insect that is identified. Forensic entomologists collect samples of every species present on the cadaver making sure to account for the temperature, as their life cycle is dependent on suitable weather conditions. Since the identification of maggots can be difficult, they will usually raise the maggots to adulthood to confirm their species. Through laboratory studies, scientists have established the developmental rates of key necrophagous insects developing at a constant temperature. This information provides forensic entomologists with a measurement called accumulated degree days (ADD), using this they can adjust for the temperatures and other environmental conditions to accurately determine the PMI.

The field of forensic entomology is rapidly proving itself to be one of the most reliable methods of crime scene investigation. The information these tiny insects hold is endless, maggots can hold a victim’s DNA, which would be incredibly useful in the case where a body has been destroyed. They can also be analyzed to test if a victim had been taking drugs, or poisoned. Maggots can also consume and be tested for gunshot residue; experiments are currently being done to identify bomb residue down to the type of bomb used. The use of forensic entomology to help solve war crimes is a relatively new and exciting topic, if you would like to learn more about it I would recommend checking out Crime Scene Intelligence: An Experiment in Forensic Entomology by Albert M Cruz. As you can see, forensic entomology is an incredibly gross and important study. In every murder there are thousands of tiny witnesses, like puzzle pieces waiting to be assembled to reveal the whole picture.

[sophisticatedscientist]

So, what's your body count?

The body farm at the University of Tennessee has housed more than 1800 corpses and 1700 skeletons. These bodies have been donated for the advancement of decomposition science. The bodies are exposed to several different scenarios and left to do their thing- you know rot and such. Some of the conditions replicate what would happen if a body were; locked in a trunk, submerged under water, hidden under leaf litter, run over by a lawn mower (yes this was a real study), encased in concrete, and frozen, the possibilities are endless. Studying these scenarios help researchers, coroners and crime scene investigators understand how long it takes for a body will decompose in various situations. I hope that this post will give you some insight into the stages of body decomposition and the various types of insects that help with process along the way.

The first stage of decomposition occurs shortly after death and is known as Pallor mortis. Once the heart is no longer beating, the body’s cells can no longer maintain homeostasis. This causes the skin to go pale and the body limp. Next is the onset or Algor Mortis, the corpse begins to cool down and now has a real Edward Cullen vibe and is cold to the touch. Between 20-30 minutes after death, Livor Mortis sets in, and the blood will pool into the interstitial tissues the body. Causing putrefaction of internal organs, skin staining and purple patches of skin that look like giant bruises. At this point moving a corpse can be very tricky, as the release of hydrolytic enzymes cause a loosening of the epidermis and dermis which can result in the skin slipping all over the place. In the instance where fingerprints are needed the technician wears the skin on their hands to take fingerprints. Buffalo Bill from Silence of the lambs would be proud.

During the second stage the corpse becomes a feeding ground for bacteria. Green bottle flies, flesh flies, and house flies swarm body cavities, entering the corpse, and laying their eggs. Within the first 24 hours those eggs hatch into cute little maggots that eat their way deeper into the corpse. Have you ever heard of the myth that hair and fingernails continue to grow after death? Well, in a sense they do! When your body shrinks and muscles stiffen, known as rigor mortis. They push on hair follicles and nails, which makes it look like they have grown longer.

Within a few days the feeding frenzy of fly’s and maggots leads to bloat. Maggots move as one mass over the corpse, spreading bacteria which releases gases like hydrogen sulfide, carbon dioxide and methane. These gases cause the corpse to swell up to twice the original size! This gas also acts as an attractant to other insects, it lets them know that the party is in full swing! With the increase of juicy fly larvae, the predatory beetles such as rove beetles, carrion beetles, hister beetles and the Devils Coach- horse beetle make their way onto the corpse, devouring maggots and laying eggs inside of the corpse. Unfortunately for the maggots there is one more party guest, the Parasitoid wasp. They are known to implant their eggs inside the maggots, who then get eaten alive from within. At this point the corpse has become both a banquet and a slaughterhouse.

After three days of decomposition, the corpse moves onto the third stage, Purge. The build- up of gases put a lot of pressure on your skin and muscle tissue. This bloating can cause the corpse to “pop”, these ruptures release gases and the liquefied internal organs start to seep out through the eyes, nose, mouth, and any other large orifice. This purge is very rich in nitrogen, so rich that the plants will all die off but in about a year the soil will be rich and ready to sustain life. At almost every stage of decomposition, the corpse has provided nutrients and a home for many insects. However, it’s not just insects that love eating a corpse, several species of fungi enjoy the chemical by-products of decaying flash as well. The two main groups are ammonia fungi, these guys feed on urine and feces, and post-putrefactive fungi that grow and feed on the corpse.

Within six months to a year, given the right conditions comes the final dry stage. The soft tissue has been consumed by animals, insects, of fungi. Leaving the corpse as nothing but a pile of cartilage, bones, and loose hanging scraps of skin.Human decomposition is a complex process with many different factors that can change the rate of decomposition. The work done at the body farm, highlights this and has allowed law enforcement and investigators to uncover some of the mysteries of death. Every stage of decomposition holds secrets and clues that provide new insights for forensic investigators.

[sophisticatedscientist]

Beetles that turn death into dinner

This article follows the work of two scientists. One studying soil, she describes soil as the “breathing skin of the planet, full of myriad different, beautiful forms of invisible life” and another studying how carrion beetles use their immune system to defend their babies and the carcass they are feeding on against microbes. They never would have guessed that their perspective fields of study would have so much in common. Their research opens the reader into a world most have yet to explore. Insects such as the carrion beetle are masters of death, they have the ability to turn death into life.

Carrion beetles can smell a carcass from kilometers away. They use this carcass to raise a family, producing gut antimicrobial secretions that protects themselves and their brood from fungal and bacterial invasions. Carrion beetles are incredible parents, they stay with their young long after they have hatched. It is together, as a family that they devour carcasses providing important nutrients for our earth. Carrion beetles have a vital role to play in soil biology, making them a central part of a functioning ecosystem.

I can agree that corpses stuffed with creepy insects is not the most pleasant thought, but I hope that reading this article can give readers a different perspective of our friends, the carrion beetles.

[sophisticatedscientist]

Hello!

My name is Bronwyn, I am a fourth-year biology student at the University of New Brunswick. I enjoy all things biology; bugs, bacteria, botany, you name it! With such a wide scope of interests I have found myself in some very interesting courses. I have taken classes like botany, entomology, microbiology, etc. When I am not studying or working at the science library, you can find me tinkering about on my farm or at the fire station either training or responding to a call.

My passion for biology has recently extended into the field of forensic entomology and I hope to share a little bit about that topic with you on this blog. Forensic entomology combines two of the most interesting topics- decomposition, and entomology. Bugs and bodies just go together, it’s a fact. Sort of like peas and carrots or something less disgusting like peanut butter and jelly. Where there is a dead body, there will be necrophilous insects. Forensic entomology can help determine the time of death, the location of death and other very useful information that can be used in a criminal investigation. In this blog we will dive into human decomposition we will learn all about the different insects that colonize cadavers. Science stuff aside, wouldn’t it be nice to know what’s in store for you ‘beyond the grave?'