The lovebug, Plecia nearctica, is a member of the family of march flies. It is also known as the honeymoon fly, kissingbug, or double-headed bug. The adult is a small, flying insect common to parts of Central America and the southeastern United States, especially along the Gulf Coast. During and after mating, adult pairs remain coupled, even in flight, for up to several days. 
The lovebug was first described in 1940 by D. E. Hardy from Galveston, Texas. At that time, he reported the incidence of lovebugs to be widespread, but most common in Texas, Florida, Alabama, and Louisiana. However, by the end of the 20th century the species had spread heavily to all areas bordering the Gulf of Mexico, as well as Georgia, and South Carolina. L. A. Hetrick, writing in 1970, found it very widespread in central and northern Florida and described its flights as reaching altitudes of 300 to 450 metres (980 to 1,480 ft) and extending several kilometers over the Gulf. In 2006, it was reported as far north as Wilmington, North Carolina.
Immature lovebugs larvae feed on partially decayed vegetation in the landscape and, in this respect, are beneficial. Adults primarily feed on nectar from various plants, particularly sweet clover, goldenrod, and Brazilian pepper. 
Semi-annual pest status
Localized lovebug flights can number in the hundreds of thousands. The slow, drifting movement of the insects is almost reminiscent of snow fall except that the flies also rise in the air. Two major flights occur each year, first in late spring, then again in late summer. In south Florida, a third (but smaller) flight can occur in December. The spring flight occurs during late April and May, and in the summer during late August and September. Flights extend over periods of four to five weeks. Mating takes place almost immediately after emergence of the females. Adult females live only three to four days, while males live a little longer.
This species' reputation as a public nuisance is due not to any bite or sting (it is incapable of either), but to its slightly acidic body chemistry. Because airborne lovebugs can exist in enormous numbers near highways, they die in large numbers on automobile windshields, hoods, and radiator grills when the vehicles travel at high speeds. If left for more than an hour or two, the remains become extremely difficult to remove. Their body chemistry has a nearly neutral 6.5 pH but may become acidic at 4.25 pH if left on the car for a day. In the past, the acidity of the dead adult body, especially the female's egg masses, often resulted in pits and etches in automotive paint and chrome if not quickly removed. However, advances in automotive paints and protective coatings have reduced this threat significantly. Now the greatest concern is excessive clogging of vehicle radiator air passages with the bodies of the adults, with the reduction of the cooling effect on engines, and the obstruction of windshields when the remains of the adults and egg masses are smeared on the glass.
Lovebug adults are attracted to light-colored surfaces, especially if they are freshly painted, but adults congregate almost anywhere apparently reacting to the effects of sunlight on automobile fumes, asphalt, and other products affected by environmental factors still not completely understood.
Much speculation about the lovebug still thrives. This is partly because the larval form of this insect is seldom seen, as it lives and feeds in the thatch of grasses for most of the year. While various fungi are suspected of being natural controls for this species, biological control of these non-pest flies is not a priority for funding.
Research by L.L. Buschman showed that migration explained the introduction of the lovebug into Florida and other southeastern states, contrary to the urban myth that the University of Florida created them by manipulating DNA to control mosquito populations.
Lovebugs are subject to some significant natural controls, such as various parasitic fungi, and dry weather—which dries out the thatch resulting in a higher mortality rate for the immatures. As the lovebug migrated around the Gulf Coast, first to Texas, then Louisiana, then further eastward, the initial populations for many years were so excessive that they caused public concern and initiated rumors of their origin. However, as pest populations migrate naturally, their natural controls are usually not far behind. While it often took decades, lovebug flights are no longer present in the huge numbers that once existed simply because their natural controls (mostly fungi) caught up with established populations. In many areas, local lovebug flights may only be present in excessively large numbers due to occasional local conditions that may not be repeated in successive years.
While lovebugs are not a favored food of most insectivores due to their acidic taste, lovebug larvae—and some adults—are food for birds such as quail and robins. Arthropod predators include spiders, some predatory insects such as earwigs, at least two species of beetle larvae, and centipedes.
- Hardy, D. E. (1940) "Studies in New World Plecia (Bibionidae: Diptera)". Journal of the Kansas Entomological Society 13: 15–27.
- Denmark, Harold; Mead, Frank; Fasulo, Thomas (April 2010). "Lovebug, Plecia nearctica Hardy". Featured Creatures. University of Florida/IFAS. Retrieved 22 September 2010.
- Leppla, Norman (September 2009). "Living with lovebugs". Electronic Data Information Source of UF/IFAS Extension. Institute of Food and Agricultural Sciences, University of Florida. Retrieved 23 September 2010.
- Hetrick, L. (March 1970). "Biology of the 'love-bug', Plecia nearctica (Diptera: Bibionidae)". Florida Entomologist. Entomological Society of Florida. Retrieved 23 September 2008.
- Mousseau, Timothy (July 2009). "Lovebugs on the move". University of South Carolina. Retrieved 23 September 2010.
- Short, Donald (May 2003). "Lovebugs in Florida". Electronic Data Information Source of UF/IFAS Extension. Institute of Food and Agricultural Sciences, University of Florida. Retrieved 17 July 2008.