The lovebug (Plecia nearctica) is a species of march fly found in parts of Central America and the southeastern United States, especially along the Gulf Coast.
The species was first described in 1940 by D. E. Hardy, though it had been observed in Louisiana as early as 1911. At the time, Hardy reported the distribution of lovebugs to be widespread, but more common in Texas and Louisiana than other Gulf States. By the end of the 20th century, the species had spread to all areas bordering the Gulf of Mexico, the entirety of Florida, and had spread as far as Georgia and South Carolina. L. A. Hetrick, writing in 1970, found the bug was also widespread in central and northern Florida and described its flights as reaching altitudes of and extending several kilometers over the Gulf.
Lovebug larvae feed on partially decayed vegetation in the landscape and, in this respect, are beneficial to humans. Adults primarily feed on nectar from various plants, particularly sweet clover, goldenrod, and Brazilian pepper.
Semi-annual pest status
thumbnail|Lovebugs at a [[bus stop at Walt Disney World Resort in September 2006]]
Male/female pairs (joined tail-to-tail) will hover in the air, drifting slowly. Two major flights occur each year; the spring flight occurs during late April and May, and the summer flight occurs during late August and September. Flights extend over periods of four to five weeks. In South Florida, a third (but smaller) flight can occur in December. Because airborne lovebugs can exist in enormous numbers near highways, they die in large numbers on automobile windshields, hoods, and radiator grilles when vehicles travel at highway 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. 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 by the bodies of the adults, with a 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 eggs generally hatch after 2–4 days, depending on the flight season. Once the eggs have hatched, the larvae start feeding on the decaying material around them, such as decaying plants on the soil and other organic material, and live and remain in the soil until they develop to the pupa stage. Lovebugs typically stay in the pupa stage about 7–9 days before reaching the adult phase, in which they can start reproducing.
Once adults, lovebugs are ready to start copulating to begin reproducing. Adult male lovebugs emerge first from the pupal stage and hover around until female lovebugs emerge. Mating between lovebugs takes place immediately after the emergence of the adult females. A male lovebug copulates and will remain paired up until the female has been fully fertilized. Copulation takes place for 2–3 days before the female detaches, lays her eggs, and dies. Adult females have been recorded to live up to seven days, while adult males may live up to two to five days, but on average, lovebugs live three to four days. However, Thornhill (1976c) recorded recapture data that showed males lived longer in the field than females.