15 May 2019

Love is in the Air - Lovebugs, that is! : A Lowcountry Tail

Note: Dennis Adams, former Information Services Coordinator, now retired, wrote the following article about the Lowcountry's favorite(?) insect. (At least it doesn't bite - which is more than I can say about most lowcountry insects.) The article was on the Beaufort County Library's website for many years until the Library switched to Wix software in 2016. Dennis last updated the article in 2007. (My! how time files - poor pun intended.) I am reposting the article with only minor edits and additions which are shown below in italics - but I do not claim credit for the scientific names and book titles show in italics below. Those are typically printed in italics. Latest update: 17 June 2021

Lovebugs by Dennis Adams, 2007: 

Clouds of "lovebugs" swarm over Beaufort - and other parts of the lowcountry - in April and May and mid-September to October each year. Dr. Timothy A. Mousseau of the University of South Carolina says that "many people don't realize that these flies are actually invaders from Central America and have been working their way northward along the coast." The invasion began around 1920, and winds first carried the insects to Louisiana. Further, there is no truth in reports that lovebugs were introduced to the United States by misguided insect researchers.

Lovebugs are now found from Costa Rica, Guatemala, Honduras and Mexico to South Carolina, Georgia, Florida, Alabama, Louisiana, Mississippi and Texas. These black flies have a red thorax. They are not true "bugs," despite the "lovebug" nickname. The BugGuide website classifies the insects this way:

Kingdom Animalia (Animals)
   Phylum Arthropoda (Arthropods)
      Subphylum Hexapoda (Hexapods)
          Class Insecta (Insects)
              Order Diptera (Flies)
                  No Taxon ("Nematocera" (Non-Brachycera))
                        Infraorder Bibionomorpha (Gnats, Gall Midges, and March Flies)
                               Family Bibionidae (March Flies)
                                      Genus Plecia (Lovebugs)

The scientific name is Plecia nearctica, of the same Order Diptera as house flies and mosquitoes, so the insect's other nickname - "honeymoon fly" - is more apt. Though scientists have identified more than 200 species in the genus Plecia, only two species fly around the United States. Plecia americana is the second species, ranging from North Carolina to Mexico and appearing only in April, May and June. This woodland insect stays away from highways.

You can see images of Plecia americana and Plecia nearctica on the BugGuide website

According to Simon and Schuster's Guide to Insects, the mowed grass rotting along interstate highways have been the ideal breeding ground for lovebugs. The larvae also develop under cow manure. Generous rainfall and mild winter temperatures increase the numbers of lovebugs. Rains from September 1999's Hurricane Floyd accounted for a bumper crop of these "honeymoon flies" in the South Carolina Lowcountry. So with fewer owners now burning off their woodland properties each year and more cattle in bigger and better pastures, numbers of lovebugs are sure to grow.

Wikipedia https://en.wikipedia.org/wiki/Lovebug


It should come as no surprise that the nickname comes from the lovebugs' habit of mating while coupled in midair. The males' eyes are four times larger than the females', the better to spot a mate in a swarm. Up to eight males may compete for a single female. Females are the larger partner and live for only 72-86 hours, the males last nearly 92 hours. Pairs stay coupled for about 56 hours with successful fertilization taking about 12 1/2 hours, though larger male rivals may disrupt and separate the couples. Mating lovebugs do not appear to uncouple in flight or at night, and will continue to feed on nectar or pollen during their couplings. The male transfers not only sperm but also protein and sugar to nourish the female and her 152 to 600 eggs. "The male is an empty shell afterwards," said Mousseau.

Lovebugs vary in size by gender with males being the smaller. Males grow to about 1/4 inch while females tend to be around 1/3 inch in length.

Lovebugs may reach a height of 1500 feet in flight. It is apparently the larger female who does the flying for the couple. Each generation cycle lasts about four weeks.

Though lovebugs do not sting, bite, or carry disease, they do spatter thousands of auto windshields and clog countless radiators. The University of Florida's "Living with Lovebugs" by Norman C. Leppla terms them a "nuisance past, as opposed to destructive or dangerous." 

"They are drawn to vehicle vibrations and fuel vapors exposed to sunlight," wrote Bradenton (Florida) Herald reporter Brian Neill, "and they prefer diesel fuel over regular gasoline." Mousseau doubted that fuel vapor attracts lovebugs, however. He believed that lawn mowers stir up lovebugs that are hiding in the grass and vehicles hit insects that are on their way to lay eggs along the damp roadsides. Leppla confirmed that lovebugs are attracted to certain essential oils and chemical compounds, including one emitted from automobile exhaust systems that are quite similar to those emitted from decaying organic matter so enticing to an egg-bearing female lovebug. Heat from auto engines may also attract lovebugs. Leppla sums it up this way: "Lovebugs apparently accumulate in relatively warm, humid, sunny areas with food and chemicals in the atmostphere that mimic oviposition sites."

Clemson Cooperative Extension offers some practical advice regarding minimizing lovebug splatter in its Factsheet: Avoid driving during their active period -- which is 10 AM to dusk; By driving slower, the lovebugs might be able to fly out of the way of your vehicle; and Consider a grill or hood cover to prevent clogging up your car radiator or damaging your paint finish. 

Decaying lovebugs release a mild acid that can etch auto paint surfaces, especially when bacteria is left to interact with the "gunk." Leppla states that lovebug viscera is not permanently damaging unless it is left to bake in the sun for more than 24 - 48 hours. The best remedy is to use a car wax on a regular basis, soak the car surface with water and apply 15 to 20 minutes of "elbow grease," and remove the lovebugs spatter within 24 hours. The maligned lovebugs also play a helpful role: their larvae help to recycle decaying organic matter.

Hungry birds are the lovebugs' natural enemies, along with some spiders and dragonflies, but the insects are hard to control. Chemicals dropped by airplanes in the late 1960s killed few bugs and cleared the highways for only a half hour. Though a type of fungus has killed up to one third of larvae in a more recent test, researchers are far from any real solution to the lovebug problem. And because the lovebugs are classified as nuisances rather than dangerous, there is not much incentive to apply limited scientific research funds to the insect. Leppla says that "it is best just to avoid lovebugs if they become a nuisance during their brief appearances each year."

And pity poor Florida! In addition to the big "plagues" in the spring and fall, small numbers of lovebugs have been spotted there every month except November. A bumper crop occurred in 2019 due to warm weather from October to April. 

Sources:

"Living with Lovebugs" by Norman C. Leppla, UF/IFAS Extension, University of Florida, latest review December 2018.

"Love Bugs Love Wetter Weather" by Lynne Langley, Charleston Post and Courier (Charleston, SC), 24 September 1999, pp. 1-A, 19-A.

"Lovebugs Factsheet," by Eric P. Benson, Amy L. Kilpatrick and patricia A. Zungoli, HGIC 2432, 2 August 2004, accessed 15 May 2019.

Simon and Schuster's Guide to Insects by Ross H. Arnett and Richard L. Jacques, New York: Simon and Schuster, 2981.

The University of Florida and the Florida Department of Agriculture and Consumer Services maintain an in-depth page about lovebugs.

"Warm, Wet Weather May Bring Epic Lovebug Season" by Jan Wesner Childs, 7 May 2019, Weather Channel website, Accessed 15 May 2019.

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