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Unexpected Treasure: The Entomological Value of Bycatch Examination

bycatch samples

Over more than two decades of mosquito surveillance at the Florida Keys Mosquito Control District, research director Lawrence Hribar has examined bycatch in traps, resulting in new distribution records for new distribution information for 98 species of Diptera, 35 copepods, 14 lepidopterans, and one species each of Hemiptera, Hymenoptera, Amphipoda. Among the Dipterans were various species of flies (left) and a new fungus gnat species, Calusamyia hribari, shown at right. (Photos by Lawrence Hribar)

By Melissa Mayer

You’ve probably heard the saying “one man’s trash is another man’s treasure,” but new research published in June in the Annals of the Entomological Society of America takes that folk wisdom to a new level. For Lawrence Hribar, research director at the Florida Keys Mosquito Control District (FKMCD) and author of the paper, the non-target organisms caught during surveillance activities represent a trove of scientific data.

So Many Insects, So Much Time

FKMCD has surveilled for mosquitoes for 22 years, deploying weekly traps at 105 sites and collecting daily samples on the mosquito control inspectors’ routes. That’s a lot of mosquitoes—and even more bycatch.

Melissa Mayer

Melissa Mayer

After picking out the mosquito specimens for counting and identification, the team examines that bycatch. Over the past two decades, this has enabled Hribar and his colleagues to extend the documented ranges of some insects, set records, report on seasonal abundance, and identify seven brand new species.

“There’s so much out there that we know so little about,” says Hribar. “There are many insects, even very common ones, for which we do not know the true geographic distributions. Examining bycatch gave me an opportunity to become familiar with families of flies that I’d otherwise not have encountered.”

Hribar presents new distribution information for 98 species of Diptera (including four crane flies, eight chironomid midges, 23 biting midges, and six mosquitoes, among others); 35 copepods (increasing the number of species in the Florida Keys from one to 36); 14 Lepidoptera (mostly plume moths); and one species each of Hemiptera (thread-legged bug Empicoris subparallelus), Hymenoptera (fairyfly Alaptis globosicornis), and Amphipoda (lawn shrimp Talitroides sp.).

That last one was quite unexpected. “Finding the lawn shrimp in the trap was a surprise,” says Hribar. “I didn’t even know there were such animals. In doing the literature review it struck me how many people have the same concerns—all these insects are being collected, can’t we get some information rather than tossing them into the trash?”

The Buzz Around Florida

Hribar sent a survey to all 64 mosquito control programs in Florida. He received responses from nearly 61 percent of recipients and discovered that just over a third of those examine bycatch at least some of the time.

Lawrence Hribar

Lawrence Hribar

For some agencies, the decision about how to handle bycatch lies with the person processing the traps. Some respondents reported saving specimens for education programs and one even used bycatch as fishing bait. Interestingly, about half of the responding agencies have an entomologist or biologist on staff with experience in insect identification, and Hribar reports a moderate correlation between that and bycatch examination.

When it comes to why so much of this bycatch goes unexamined, Hribar says that, in the Florida Keys, mosquito trap catches can reach the tens of thousands per night. Processing just the mosquitoes is labor-intensive, and some agencies and individuals may perceive bycatch examination as too expensive and worry that the task splits the staff’s attention.

Hribar doesn’t see it that way. For him, bycatch examination is a solid return on public investment since it could expand local knowledge bases and alert localities to emerging disease vectors or agricultural pests. Still, he says another option is to simply measure and record the quantity of bycatch without attempting species identification since this data may reveal trends over time.

Big Catch, Big Opportunity

For those interested in examining bycatch, doing so could fill in the knowledge gaps that impede invertebrate conservation efforts. This includes finding undescribed species and uncovering new information about a species’ distribution, abundance, and relationship with the environment.

Filling in these knowledge gaps requires long-term data collection, and Hribar says mosquito control programs are uniquely positioned to do that. Pressing issues like habitat destruction and climate change—and even the possibility of broad-scale declines in insect abundance or biodiversity—add a sense of urgency, with Hribar noting “an imperative to collect what we can while we can” in the paper.

For Hribar, the take-home message is that it’s never too late to start collecting this data. To agencies and individuals whose interest is piqued by his findings, he urges, “I’d say, ‘Do it.’ Pick one group, one order, maybe one family, and start collecting. You don’t have to do everything, just do something.”

Annals of the Entomological Society of AmericaRead More

Expanding Basic Entomological Knowledge by Using Mosquito Surveillance Bycatch

Annals of the Entomological Society of America


Melissa Mayer is a freelance science writer based in Portland, Oregon. Email:


  1. Very interesting and not unexpected. I also see many unexpected insects being given to PMP’s by homeowners for “what is this”?. When I get them and identify then the literature on their expected locations is off by 2-3 states many times. Operaating up in New England I now know of many insects that would be considered “invasive” form literature printed 10-12 years ago..

  2. I have six years of monthly insect samples collected with directional UV traps at two contrasting locations 1) Chihuahuan Desert near Big Bend National Park (Terlingua Ranch ~ 10 inches PPT per year) and Central Texas Live Oak Savanna south of Austin Texas (Freeman Ranch near San Marcos, Texas ~35 inches PPT per year). Collections were made during the new moon phase, and include a wide range of taxa. Samples were collected from Feb. through November. Samples need to be sorted and identified – there are probably numerous un-described species. I can provide more details. I’m trying to find someone with the interest and resources to process the samples and publish the numerous papers that would come out of the analysis. I hate to discard the samples, since they represent a unique time period in the potential decline of insect abundance. Contact me for more details –

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