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UF Firefly Expert Marc Branham Discusses Insect’s Future

Like fireflies? Here, Dr. Marc Branham “sheds some light” on their situation.

The BugWeek Web Team is acutely aware that many, many species of insects and other arthropods are not popular with the human race.

It’s understandable. Regrettable, but understandable.

Some bugs eat our food crops and chew up our decorative plants; others transmit pathogens that cause diseases or make us itch; some enter our living spaces and give us the creeps.

This story isn’t about those bugs. It’s about one group of beetles that many people actually like to see, especially at night — fireflies.

Did you catch the word “beetles” a moment ago?

That’s right. Fireflies aren’t flies at all, though they have wings and are often seen traveling through the air.

They’re all members of the Coleoptera order and, more specifically, the Lampyridae family.

Worldwide, there are about 2,000 species of fireflies. Many of them — not all — produce light, something they do to signal potential mates or attract prey.

It so happens that Florida has more firefly species than any other U.S. state.

And the University of Florida’s Department of Entomology and Nematology has two of the world’s leading firefly experts. One is James E. Lloyd, a professor who’s now retired but still active in the department, and has studied fireflies since 1962. The other is Lloyd’s successor, Marc Branham, an associate professor who’s been here since 2003 and began studying fireflies in the mid-1990s.

This year, Dr. Branham is also the Conference Host and organizer of a major academic event, the International Firefly Symposium. It takes place Aug. 11-15 at the Hilton University of Florida Conference Center. The symposium takes place every few years, drawing scientists, educators, artists and other firefly enthusiasts from around the globe.

Not surprisingly, Drs. Branham and Lloyd will both be presenting; Dr. Branham will take part in five discussion sessions; Dr. Lloyd will deliver the symposium’s keynote address.

Registration is required to attend the symposium, and much of the material presented there will be technical in nature. The BugWeek Web Team always wants to make entomology accessible to the general public, so we decided to use the symposium as an excuse to sit down with Dr. Branham to talk about fireflies in much more general terms.

We hope you enjoy the following excerpts from our 60-minute discussion:

Q: So, has firefly season started in Florida yet?

A: Yes, right now fireflies are out there, we’re starting to see them at night.

Q: How are fireflies doing in Florida these days?

A: In Florida, the situation with firefly populations is both good and bad.

There are more species in Florida than in any other state in the U.S. That’s one reason why I came here. That’s good.

One of the bad things is, if you ask a lot of Floridians they’ll tell you they haven’t seen many fireflies in recent years — or any. That’s partly because the populations here are localized. It’s a tropical phenomenon — there are more firefly species present, but fewer individual insects present from each species. I’m originally from Kansas, where we have fewer firefly species but you can see thousands of insects from each species. I think that’s what a lot of people think of when they think about fireflies, incredible displays.

Jim Lloyd has worked on fireflies for more than 45 years. He’s been showing me a lot of his favorite study sites in this part of Florida. Time and time again we’ll go somewhere, see nothing, and he says, “well, they used to be here.”

There are a lot of things impacting fireflies. Some of the factors include:

Things drying out – places that used to be swampy aren’t swampy anymore. I’m not sure if this is due to climate change, or if aquifer levels are dropping, or if something else is going on. But in these areas that are drying up, the fireflies can’t find prey anymore, the snails and slugs that the larvae feed on.

I tell lots of people that light pollution at night is playing a big role. When I was a kid, people didn’t use architectural accent lights on their homes, and streetlights were less common. The problem is, fireflies divide up the night into blocks of time, and certain species appear at specific times of night. The fireflies decide to come out based on how dark it is. But if it never gets dark enough, they never come out.

Porch lights can interfere with males and females seeing each other. We have experiments that looked into this – if there’s a lot of ambient light from artificial sources, the fireflies have a hard time seeing each others’ flash patterns.

Q: How widespread is the decline in firefly populations?

A: Over the years, the numbers seem to be declining all across the United States.
It’s believed that a number of species have gone extinct in Florida. There are probably three or four that we can’t find, anyway.

Q: How can the average person encourage firefly populations?

A: If folks would like to have fireflies on their property, there are a couple of things they can do.

One is, decrease pesticide use, because you may inadvertently kill fireflies while you’re targeting other organisms. Another thing is, eliminate the use of man-made lighting in the evening.

I feel strongly that people preserve what they value. However, I think that, more and more, successive generations are not spending much time outside interacting with nature, and as a result I wonder if they will value nature. Nearly every child is a naturalist at some point. I want kids to look for and watch the critters wherever they are. If they develop a positive, personal experience in nature, maybe they will push to conserve it.

Q: Speaking of kids, how do you feel about the practice of kids catching fireflies and putting them in jars?

A: I tell kids that it’s fine to collect them in jars to look at, but they should release them the same night, because it’s good to conserve fireflies. They don’t live long in a jar without moisture.

Q: Final thoughts?

A: We need to talk to our children about conservation and biodiversity. I would hate to experience a summer night without fireflies….