A typical crane fly on the outside of a building. Photo credit: Carrie Stevenson, UF IFAS Extension
All my life, I’ve known them as mosquito hawks. Built like extra-large, spindly-legged versions of mosquitoes, they look a bit intimidating. However, growing up we were told they were harmless and actually fed solely on mosquitoes. In the days before Google, I just accepted it as fact and was glad to see them around.
In early March, there was a bit of an invasion of these insects. I started seeing them everywhere outdoors and inside my office building. They are slow movers, bouncing in the air more than flying. After several days of seeing them everywhere, though, they pretty much disappeared.
Several crane flies appear to have met their demise inside my office building. Photo credit: Carrie Stevenson, UF IFAS Extension
Like much folk wisdom accrued through my life, the story of the mosquito hawk is not totally true. They are harmless, that much is correct. While many people do know them as mosquito hawks, the accepted common name is the crane fly. Crane flies come in a wide variety of sizes and colors, ranging as some of the smallest and largest species in the fly Order, Diptera. Their diversity is rather mind-blowing, with the Family Tipulidae including about 15,000 species of crane flies worldwide.
Crane fly larvae live in aquatic environments and feed on decaying plant material. Photo credit: North Carolina State University
As for being voracious predators of mosquitoes, we have no such luck. Crane flies barely eat at all, because their adult life span is as short as those two weeks I recently noticed them around. They spend most of their lives as aquatic larvae, living in streams, pond edges, and rotting vegetation. Adults do not have the right mouth anatomy to eat other insect prey, instead drinking only by sponging up water in dew form or taking nectar from plants. Their primary purpose in adulthood is to complete the mating process. Females lay eggs near water, hence the location as larvae. After this hedonistic spring break experience of adult life, they die.
Crane flies, in both larval and adult forms, are popular snacks for other wildlife. The adults are easy targets for birds and bats. The larvae, which in some species are as large as a pinky finger, are tasty morsels for fish and amphibians. During their larval existence, crane flies ingest debris, helping with the decomposition process and filtering the water bodies they live in. Despite their short life span, crane flies make an outsized contribution to the food web.
Recently, I’ve been asked about a deer fly trapping method that I wrote about a number of years ago. So, here it is. This aggravating insect is active now.
Deer flies, which are in the horsefly family, are annoying as they repeatedly and persistently dive for their victims until they inflict a painful bite.
Dr. Russ Mizell, now retired UF/IFAS Extension entomologist, experimented with a method to trap this insect. Mizell wanted to identify the optimum shape, size, color and speed to attract deer flies. If successful, he could temporarily remove a deer fly population long enough to enjoy an outdoor gathering without being bothered by deer flies.
Mizell said he started the research as a high school science project with his son but “it got so interesting, I just kept doing it.”
Deer flies wait for prey to walk before attacking. So, they are highly attracted to movement.
With this in mind, Mizell and his son decided the best way to snare deer flies was to “troll” for them from a slow-moving vehicle. Working in spring and summer when deer flies are most prominent, they set out to discover what kind of trap worked best.
They built a test platform on the hood of their vehicle that could troll seven different shapes at once. They ambled along in deer fly-infested countryside for set periods of one to five minutes, testing pyramids, squares, balloons, plant containers and other shapes, all coated with Tanglefoot (commercially available sticky spray for insects), then counting immobilized prey. They tried black, tan, blue and shapes of other colors suspended from various heights.
The trap that enticed the most deer flies proved to be a 6-inch flowerpot painted bright blue and coated with Tanglefoot. This trap captured as many as 30 deer flies in a one-minute test. It worked best when suspended three to six feet above the ground and trolled no faster than 10 feet per second or about 7 miles per hour.
The traps are remarkably effective, Mizell said. “Many times, after running the traps through an area, we found there were no deer flies left,” he said. “You trap them out for a short period until they repopulate the area.”
The traps also work when attached to a baseball cap and trolled by the hat’s wearer. But instead of attaching a flowerpot to your cap, you could attach a blue drink cup painted with Tanglefoot.
Despite its effectiveness, its aesthetic appeal leaves something to be desired.
A threadleaf sundew in bloom, with its series of buds trailing down. Photo credit: Carrie Stevenson, UF IFAS Extension
The mucky, sunny spaces here in northwest Florida are inevitably full of beauty and surprises. Due to the sopping wet, acidic, and nutrient poor soil, plants in these areas must make some unusual adaptations. Wetland bogs are home to several interesting and carnivorous species, like pitcher plants and sundews. Most sundew species I come across are the tiny, pinwheel shaped dwarf sundews (Drosera brevifolia), which lie prone to the ground.
At a recent visit to the Roy Hyatt Environmental Center, I noticed a showy purple flower that at first I assumed was a meadow beauty.
Threadleaf sundew leaves glisten in the sunlight adjacent to a crop of purple flowers growing from separate stems. Photo credit: Hugh and Carol Nourse
Lavender, four-petaled meadow beauty flowers are common in wet areas. However, this plant was a bit different. First, it had five petals; but even more unusual was that something akin to a green caterpillar was hanging from every flower bloom. Intrigued, I bent closer and saw that the green segments were not a dangling invertebrate, but a series of fuzzy green flower buds. The bud closest to the purple flower was a deep violet and close to flowering.
Fields of curled fiddlehead leaves of the threadleaf sundew are a whimsical sight in wetland bogs. Photo credit: North Carolina State Extension Service (NCSES)
In all my years of exploring and leading people around pitcher plant prairies, I’ve encountered Tracy’s sundew/threadleaf sundew (Drosera tracyi)—a type of sundew with an upright, sap-covered stem—but never one in bloom.
Up-close view of a Drosera tracyi leaf. Photo credit: NC State Extension
Typically, you’ll only come across the slender, threadlike ( a structure known as “filiform”) fiddlehead leaves. These leaves look more like stems, and are bright green and covered in dewy, sticky, deadly-to-insects droplets. Insects are attracted to the shimmering drops of mucus, triggering a hormone in the plant that causes the leaf and its glands to fold over the prey. Once stuck, the insects suffocate and are digested by enzymes in the leaf glands.
The purple flowers appear in May or June, atop a single leafless stem that appears unattached to the threadleaf sundew leaves. According to the Georgia Biodiversity Portal, this series of flowers will “open one by one, from the bottom of a coiled inflorescence up, with unopened buds at the top. Flowers begin to open about 9:00 am and close about five hours later; some flowers persist for two days.” Threadleaf sundews can self-pollinate but are also attractive to bees.
In 2016, I wrote an article for Gardening in the Panhandle called “Attract Pollinators with Dotted Horsemint” introducing readers to this tough native plant that supports native pollinators. If you have flowers in your garden, you probably have pollinators and a whole lot of other insects but if you want a plant that lets you observe a really diverse palate of bugs dotted horsemint Monarda punctata.
When I find I have some downtime at home I have a habit of wandering the yard looking for interesting insects. Admittedly, I usually have my phone in hand hoping to get a great photo or video of my arthropod visitors, but it is a productive task, too. As strange as it may sound, I can count this hobby as part of my integrated pest management landscape maintenance strategy – scouting!
My favorite plant to visit on my scouting run is normally not afflicted with pests, but it hosts so many different insects it always gets a stop on my rounds. When dotted horsemint is in full flower it is visited by a lot more than pollinators. I’ve recorded daily visits from assassin bugs, ants, beetles, flies, dragonflies, spiders, thread-waisted wasps, honey bees, butterflies, and moths.
Here’s a photo album of frequent visitors to my dotted horsemint from this summer – enjoy!
