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| Dead insects could help solve crimes. |
When investigators arrive at a crime scene, some of the most valuable witnesses may be impossible to question. They have no names, no memories and no account of what they saw.
They are insects.
Researchers at the FAMU College of Agriculture and Food Sciences are studying the insects that colonize decomposing remains, using their presence and life cycles to help forensic investigators estimate how long a person has been dead and reconstruct what happened after death.
The work, known as forensic entomology, could help address a shortage of region-specific data, particularly in North Florida.
Lee Bushong, an associate professor of forensics and criminal justice, and Anamika Sharma, an assistant professor of entomology, are leading an interdisciplinary research team examining how insects respond to decomposition under Florida’s environmental conditions.
“Our goal is to better understand what insects are attracted to decomposing remains and how quickly they arrive,” Dr. Sharma said. “That information can help investigators estimate the time since death and provide valuable evidence during an investigation.”
Decomposition sets off a biological succession. Different insects arrive at different stages, creating a sequence that can help forensic scientists estimate the postmortem interval — the time between death and the discovery of remains.
Blow flies and flesh flies often appear early, followed by beetles and other species as decomposition progresses. Their presence and developmental stages can provide investigators with clues about how long remains have been exposed.
But those estimates depend heavily on local conditions.
Temperature, humidity, weather and habitat all affect insect development, making data from one region less reliable when applied elsewhere.
Florida presents particular challenges.
“Florida’s climate is very warm and humid, and insects love this kind of environment, so anything that is decomposing in this climate will decompose much faster,” Dr. Sharma said.
To study those conditions, her team uses animal carcasses as models for natural decomposition.
“We collect a dead deer carcass, and study the insects on the dead body,” she said. “We research what type of insects the carcass is attracting, at what rate and in which sequence.”
Researchers record the species that arrive, when they appear and how environmental conditions influence their development.
The findings could provide law enforcement with more reliable data for Florida death investigations.
“In North Florida, we do not have a lot of data historically available,” Dr. Bushong said. “So any data that we collect here is going to help our law enforcement and police departments.”
The research could also help investigators determine whether remains have been moved.
Dr. Sharma’s team is documenting fly species found throughout Florida, creating a geographic record that could eventually help identify where remains may have originated.
“We are right now collecting the different species of flies in Florida,” she said. “So if somebody were to move a dead body from another state and it had a specific species on it, we would be able to tell that the body has been moved.”
The researchers emphasize that insect evidence is not a perfect clock. Weather, temperature and habitat can alter both decomposition and insect activity.
“Small changes in weather, temperature, or habitat can influence insect activity and decomposition,” said Maya Mancle, who recently earned a master’s degree in entomology with a concentration in forensic entomology.
That is why Florida-specific research is important, she said.
“Florida’s warm temperatures, high humidity and diverse insect populations create decomposition patterns that differ from other regions of the country,” Ms. Mancle said. “Because insect development is heavily influenced by temperature and climate, it’s important to collect region-specific data.”
The research also serves as a hands-on laboratory for FAMU students preparing for careers in forensic science.
Dr. Sharma teaches an undergraduate course with Dr. Bushong in which students examine animal carcasses and study the insects associated with decomposition.
“I teach a class along with Bushong for undergraduate students at FAMU where they also examine dead carcasses and research the insects around the body, so they get hands-on experience early,” she said.
For Ms. Mancle, the work brought together her interests in criminal justice and science.
“My academic background combines criminal justice and entomology because I’ve always been interested in applying science to criminal investigations,” she said.
During the project, she monitored decomposition, identifying insect species and tracking their arrival and development.
“Animal carcasses serve as an excellent model because they closely mimic many of the biological processes that occur during human decomposition,” she said.
The research has shown her how insects can provide information that might otherwise be unavailable to investigators.
“Insects are often some of the first organisms to arrive after death,” Ms. Mancle said. “By identifying these insects and understanding their life cycles, researchers can estimate how long a body has been decomposing and sometimes gain insight into environmental conditions surrounding the death.”
For FAMU researchers, the broader objective is to build a scientific database that reflects Florida’s climate, geography and insect populations.
For law enforcement, that could mean more precise tools for reconstructing deaths. For students, it offers an opportunity to learn forensic science not only from textbooks but at the site of decomposition itself.
And for families awaiting answers, researchers hope the data will ultimately help investigators provide them with greater accuracy and confidence.
“The findings can improve the accuracy of death investigations,” Ms. Mancle said, “helping investigators provide more reliable information to families and the justice system.”