Next guest is Dr. Jason Byrd. Thank you very much and welcome to The Junction.

Thanks for having me.

So, what is your background and how does it relate to the field of forensics?

Well, so I'm a forensic entomologist, and, uh, we specialize in using insects to help us determine, uh, most commonly it's the post mortem interval, or portions of the post mortem interval, so how long an animal has been deceased. But entomology can be useful in determining, uh, a geographic origin, you know, where the, uh, original, uh, colonization may have been. Uh, may have occurred if the animal has been transported. Uh, we can use it for, uh, toxicology. See if there's any drugs or toxins on board. Cause you can use maggots gram for gram as you would the, the animal tissue. And, um, a genetic analysis. Because at some point in time these insects are going to leave what they were feeding on and distribute themselves out in the environment. Um, and they'll spend 60 percent of their life cycle at least out in the environment. Um, so if a crime scene investigator recovers some of these insects and they're not, are associated with the body, we have to prove that they did come from the body. So we can do a genetic analysis to, uh, A, determine their species, so we know what we're dealing with, and then B, determining what they were feeding upon to, to match it to the, you know, the animal in question or the, the human remains in question at a crime scene to prove that indeed it came from that body and then this estimation is then going to give us a post mortem interval that relates to that body.

So I know that the main question that people ask you is basically how long dead? Now, is that what the insects are actually telling you?

So there's a bit of a debate on that one. Um, so entomologists, uh, disagree a little bit, but in my work, I try to use, uh, when I send a report to an investigator, I try to target the time of colonization. That's when the flies were depositing eggs or maggot on that human or animal. Um, and I use that because that is the point that biological clock starts with the insect growth on the body. And then we can put them in environmental chambers, different temperatures, we can rear them under different light cycles, so we can put a lot of statistics to that part. So that is the time of colonization. And I can say that, you know, the individual, be it human or animal, was it dead, you know, on or before colonization, because if we're dealing with mice, those are different species. So we can, you know, rule that out in most cases. But that may not be the time of death, because the time of death could have preceded the time of colonization. And it makes sense, because somebody dies, an animal dies, it takes a while for flies to, you know, be able to show up and find it. The problem with that is, is, That's kind of a different set of research, right? Uh, fly arrival rates, how long does it take them to get there? How are they impacted by light and dark cycles as far as sunrise and sunset and different weather patterns? And that for many species, we just don't have that type of data. And even for the species that we do have, that type of data is from really limited research areas. So to avoid all of this, um, you know, one off situation that's hard to repeat and then really becomes more, um, a professional opinion than anything else. Uh, I don't, I don't put any of the pre colonization interval information in my reports. I just do the post colonization or time of colonization try to target. And then, you know, they want to know how long dead. So it's not going to maybe give them how long dead, but it gives them a huge portion of how long dead. And then sometimes that's enough, you know, it can make or break alibis, puts people in particular places at particular locations. But I feel more confident with being able to stay with what we can put some statistics to.

I love watching crime, crime shows, but I look at them for the entertainment value. Right. And looking at it, it's kind of funny about the, you know, how quickly and how decisive they are in, in their findings. But that's not really the, the case, right? Like in the, in these shows, somebody will look at. Some maggot in the field and say, this is exactly this bug. And this body has been dead for X amount. And then when I took the, the forensics masters from UFL and during entomology, I realized that the, the range that's given, it's not as precise. So what are the factors that go into that and how long can a range be?

It depends. I mean, So the range, um, one is what species is it and how much information do we have. There are some species that's never been reared in the laboratory. So if you happen to have that scene, your, your range is pretty broad because we don't know what it's doing. Um, so that is one. And even if you do research on them, there's biological variation. I mean, just think of a litter of puppies or kittens, you know, some will outgrow the other. Same thing with a, a, an aggregation of maggots that may be deposited from the same egg clutch from the same female. Some will grow a little bit larger than others. So there's that biological variation. And then, since they are so heavily influenced with temperature, the big variation in these estimates that come in is like how, how accurate do we feel we are with the thermal history of these insects? And then how close was the weather station? Is it certified data or not? And, you know, are the conditions at the scene fairly consistent with wherever we're getting the information from the weather station. So when you put biological variation, variations in weather, um, the species itself, which we may have good data on, may not. I mean, maybe some of the data was done in the fifties. So, you know, how much, how much genetic drift has happened since that time that may, you know, They may be growing faster or slower now, current populations than what was happening in the 50s. So when you put that all together, your variation can be pretty broad. So to help with that, we try to constantly do research on new species. Um, we try to maybe put data loggers at the scene, to record many more temperature data points and what your crime scene tech is going to be. And we'll try to get, you know, most of our windows of opportunity Um, let's say, you know, maybe the body's been dead for two weeks. Um, and we're trying to plot back to a time of colonization. So we can usually get that time of colonization down to usually plus or minus 36 or 48 hours or so. So not that much, um, variation at that point in time. But when you get months out, you know, maybe your variation is a week, two weeks. So it's also depending on how long your ultimate postmortem interval is as well. So can vary quite a bit in some cases.

What's the, what's the kind of information that you need from an investigator to help you do your job as far as the things that they need to collect on the scene, both insects and environmental factors?

Yeah, well, we need temperatures, lots of temperatures. The air temperature, the body temperature, the ground temperature, um, that's if it's outside. And of course, if it's inside, you know, all the interior temperatures, whether utilities were on or off, what was the thermostat set, you know, ceiling fans on, off. Okay. Doors and windows open, closed. So just the environmental temperatures is, is, is one, you know, um, large area that we would, we really need them to document. Um, and probably that's the most valuable. The other is just sample size. We often have a problem with the, um, crime scene investigators or animal control officers, you know, whoever may be making the collections, we're just not quite getting enough. You know, we need 50 or 60 to get, get a good statistical size. Uh, maybe they give us five or six. Um, and you can look at the pictures and see that there are probably some species that's just not represented in their collections. Um, so that's another one. So getting a representative sample, um, and getting enough of what they do see is usually the big challenge.

I know I, uh, many, many years ago, I sent you a case of a dog that had died in a basement and then it was moved outside and you were able to give us like we just wanted to know if the body was dead for more than a week and you were able to give us a minimum time of colonization of about three weeks. One of the things that did not happen, though, is that the primary crime scene had a lot of larval casings. And the investigator did a great job at taking photographs of it, but they did not collect any of them. So, what is the importance as far as collecting things on the scene versus waiting until the necropsy to collect them?

Well, it's most important to collect at the scene because these insects, once they're through with their feeding period, are going to wander away from the body. They don't stay associated with it. So, always the older ones. Which could be the biggest question the investigator has, you know, what's my maximum post mortem interval? Those older ones are going to distribute themselves around the scene. So if you just come in and collect off the body, pick up the body and leave, you know, you're missing probably the most important part of that picture. Then the other issue is sometimes they don't make a collection. Um, scene is done, they then realize, ooh, well we should have collected entomology, that could help us, and then they ask us to look for photos. Sometimes that's possible because some, uh, species are distinct enough that you can identify them in the photographs. But the big problem is, for the vast majority of these insect species, you have to put them under, you know, a microscope and get that level of magnification before you can really tell what they are. Um, and so in a photo from a regular, you know, digital SLR, they all look the same. And the problem with that is, they look the same, but some of them can grow very quickly. Some species and some species grow very slowly. So it's not like you can even just group them and say well I know, you know, just the, the, the average group of, um, you know, maybe the genus that this fly comes from. It doesn't help you because within that genus you can have some very fast developing flies and some very slow developing flies. So you really need the specimens themselves, um, sent to you to back up the photographs.

What's going to be the best way for investigators to collect these samples to send them to you so that you can do a good job in identification and in determination of the time?

Well, I mean, the best thing is, you know, uh, there are plenty of, um, uh, equipment checklists that are out there. So you configure yourself an entomology collection kit that has all the tools that you need before you go out and do it. Um, but we basically need, um, a live collection and a preserved collection. That live collection helps us with the identifications because the adults are usually distinct where the larvae are not. Um, so we need the collections themselves, live and preserved. We need the weather data and photographs. Um, and a collection of the adults that are just flying around the scene. Um, some entomologists say there's really no need to worry about that because we don't use them for post mortem interval estimations anyway. Um, and that's true to an extent. You don't age the adults, but the adults can help you determine what larvae are present. And the adults also can tell you what habitat, you know, you would expect to be in. Which can be important because if I see, um, you know, adult flies, they're sun loving flies, they like really hot weather, and the crime scene is indoors or in a shed, then I can tell you that at some point in time that animal was outside, it was colonized, and somebody brought it in for concealment purposes or something like that, or vice versa. You're out in the middle of an open field on a bright, sunny day, and we have a bunch of shade loving insects that like relatively cool weather, so you know that at some point in time that animal was inside and it had been dumped, essentially. So just having a good scene collection of the representative samples that are there can Also help us confirm that that scene is where that animal, um, you know, um, decomposed or, or died and wasn't transported from somewhere else and just dumped.

So the other case that I had submitted to you was a lot different because there were a large number of deceased animals and there was a lot of insect activity. However, there was no information collected on temperature, location. and the estimated time of death was six months to over two years. So is there any information that you can get from that or is that just kind of useless?

It depends on the species, really. Um, so I wouldn't say it's useless, um, with some species because And the other species will tend to recolonize year after year after year. So it really just depends on the species. But if you've got one species, we'll kind of go through their entire life cycle in a year. And then you've got new documentation that they've at least completed that life cycle, then you know it's a minimum of a year. If it's a species that are recycled year after year after year, you know, you've got a lot of dead flies on the windowsill and on the floor. You don't know what generation you're in. You know, it could be three years. So it really just depends on the species that you're dealing with as to what they tend to do and whether they recolonize the remains and start their cycle over again. Generally, they don't. That's the reason entomology works. They will deposit their eggs, they go through their life cycle, and when that species hatches out, it goes away. It's not interested in those remains anymore. So entomology is just like input and output for the vast majority of the species.

So what resources are out there for investigators and forensic veterinarians and such to learn about how to collect the specimens, how to submit them, and that kind of stuff?

Yeah, there are several books on forensic entomology, some field manuals, um, most of the board certified entomologists have their own website. Um, but yeah, I mean, it's pretty easy to be able to find a, either from books or from the internet, a checklist of the equipment that you need, uh, the various forms that you need to be able to properly document all the environmental data, uh, chain of custody forms, of course, for your entomology collections. And then, you know, the, uh, American Board of Forensic Entomology, uh, has a list of all the boarded, um, forensic entomologists on their websites and their geographic locations. So you can find the nearest boarded entomologist to you. But you don't really need a boarded forensic entomologist to get help at the scene. I mean, you know, there's only, uh, there's less than 30. Not very likely you're actually going to get them. Um, but you need an entomologist. But entomologists are everywhere. They're at our schools, museums. You know, colleges and universities, the Agricultural Extension Service. So you just need to make a relationship with an entomologist in your area to be able to help you out. And then they may have, you know, the specialized collection tools, forceps and nets and all that to be able to loan you if you're in their area. So it's not hard to get entomology help these days.

I think it's a very valuable tool, right, especially for forensics. I really want to thank you for taking the time and thank you for what you're doing.

Yeah, thanks for being here.