Lovebug larvae feed on decaying plant matter on and just below the soil surface, while adults sip nectar from flowers. That two-stage diet surprises many people who encounter these slow-flying insects splattered across car grilles every spring and fall, since nothing about a highway suggests a meal. The explanation for their roadside swarms has nothing to do with food, and the full picture of their feeding habits reveals an insect that is far more ecologically useful than its reputation suggests.
What Larvae Eat
Lovebug larvae (the immature, worm-like stage of Plecia nearctica) are detritivores. They live in the top layer of soil and thatch, feeding on partially decomposed leaves, grass clippings, and other dead vegetation. If you rake back a thick layer of lawn thatch or leaf litter in the southeastern United States during summer or early fall, you may find dense concentrations of these small, grayish larvae chewing through the organic debris.
Their preferred habitat is anywhere plant material is actively breaking down: beneath mowed grass that has been left in place, around cattle pastures where manure and plant litter mix, and along roadside ditches where mowed vegetation accumulates. Moisture matters a great deal. Larvae need a damp environment to survive, so you find them in highest numbers where soil stays consistently moist and organic matter is abundant. Dry, sandy soils with little leaf cover produce far fewer lovebugs.
Larvae spend the longest portion of the lovebug life cycle in this stage, sometimes several months. During that time they consume a remarkable volume of dead plant material relative to their size, steadily converting leaf litter into nutrient-rich waste that gets worked back into the soil. In this respect, they function much like earthworms or other soil-dwelling decomposers, cycling nutrients and improving soil structure.
How Larvae Break Down Tough Plant Material
Dead leaves and grass stems are made largely of cellulose and lignin, compounds that are notoriously difficult for animals to digest on their own. Lovebug larvae, like many other detritivorous insects, rely on microbial communities in their gut to help break these complex molecules into simpler, absorbable nutrients. This is a widespread strategy among insects that feed on decaying organic material. A review of insect gut microbiome research found that digestion of recalcitrant plant polymers is one of the most common and important roles gut bacteria play across many insect orders, alongside detoxification and essential nutrient synthesis.1PubMed Central. Most dominant roles of insect gut bacteria: digestion, detoxification, or essential nutrient provision?
The decomposition process that lovebug larvae contribute to is not just about the larvae themselves. By the time a larva ingests a piece of dead leaf, fungi and bacteria have already begun softening and breaking it down externally. The larvae are eating a mixture of plant fiber and the microorganisms colonizing it, gaining nutrition from both. Their gut bacteria then finish the job, extracting energy from whatever cellulose and hemicellulose remains. The larvae’s frass (fecal material) is further broken down by soil microbes, completing a nutrient loop that enriches the topsoil.
What Adult Lovebugs Eat
Once a lovebug pupates and emerges as a winged adult, its diet changes entirely. Adults feed on nectar and pollen from flowers. Their mouthparts are suited for lapping up liquid nectar rather than chewing solid food, so they visit blooming plants in much the same way butterflies or other nectar-feeding flies do.
Research on adult lovebug feeding behavior has shown that they are attracted to specific floral volatile compounds. A study using chemical lures demonstrated that lovebugs respond to phenylacetaldehyde, a compound commonly emitted by flowers to attract pollinators.2Florida Entomologist. Attraction of Plecia nearctica (Diptera: Bibionidae) to Floral Lures Containing Phenylacetaldehyde This confirms that adult lovebugs actively seek out flowers by scent, not just by stumbling onto them. In the wild, they have been observed visiting a range of flowering plants, including sweet clover, goldenrod, and various wildflowers common across the Gulf Coast states.
Adults do not live long enough for their feeding to be elaborate. The adult lifespan is typically just a few days to about a week, during which mating and egg-laying are the primary activities. Nectar feeding provides the quick energy adults need for flight and reproduction, but it is not a prolonged or complex dietary phase. Females that survive long enough to lay eggs deposit them in moist soil rich in decaying vegetation, completing the cycle by placing the next generation directly in their food source.
Do Lovebugs Pollinate Anything?
Because adults visit flowers for nectar, they inevitably pick up and transfer some pollen. Whether this makes them meaningful pollinators is another question. Lovebugs are not especially efficient at pollen transfer compared to bees or even some other fly species. Their bodies are not as hairy or well-suited to trapping pollen grains, and their flower visits tend to be less systematic. Still, when they appear in large numbers, they can contribute to pollination in a minor, incidental way. They are best understood as occasional pollinators rather than specialists, and no major crop in the southeastern United States depends on them for pollination.
That said, the sheer density of lovebugs during peak flight seasons means even a modest per-insect pollination contribution adds up. In natural ecosystems with abundant wildflowers, their visits likely provide some benefit to plant reproduction, though quantifying that contribution precisely has not been a research priority.
Why They Swarm on Highways
The question people ask most often about lovebugs is not really about their diet at all. It is about why millions of them hover over roads and highways, splattering windshields and clogging radiators. The answer has nothing to do with feeding. Research dating back to the 1970s established that lovebugs are attracted to automobile exhaust gases, engine heat, and the thermal updrafts created by sun-baked asphalt.3Oxford Academic. Heat, Sound, and Engine Exhaust as Lovebug Attractants
Vehicle exhaust contains compounds that chemically resemble some of the volatile organic chemicals released by decaying vegetation. One hypothesis is that female lovebugs looking for egg-laying sites are drawn to these exhaust plumes because they mimic the chemical signature of decomposing plant material, which is where larvae need to be. The heat from engines and road surfaces likely amplifies the attraction. Freshly mowed highway medians and shoulders, which combine warm pavement with cut grass releasing volatile organics, seem to be especially effective at drawing swarms.
So while lovebugs are not eating anything on the highway, the underlying reason they congregate there connects back to their diet in an indirect way. The chemical cues that guide females to suitable larval habitat overlap with the chemical fingerprint of internal combustion engines, and that overlap creates the nuisance that most people associate with these insects.
Common Myths About Lovebug Feeding
Several persistent myths surround what lovebugs eat. The most widespread is that they eat mosquitoes. This is flatly false. At no stage of their life cycle do lovebugs consume mosquitoes or any other insect. Larvae are strict detritivores, and adults feed only on nectar. The myth likely arose because people noticed lovebug populations increasing in the southeastern United States and assumed they must have been introduced to control mosquitoes. In reality, lovebugs expanded their range northward from Central America on their own, probably assisted by habitat changes like increased cattle ranching and grass cultivation, which created vast tracts of ideal larval habitat.
A related myth holds that lovebugs were genetically engineered at the University of Florida and released as a biological control agent. This is an urban legend with no basis in fact. University of Florida entomologists have studied lovebugs extensively, but the institution has never engineered or released them. The species’ range expansion was natural and driven by the availability of suitable habitat, not any deliberate human intervention.
Another misconception is that lovebugs bite or sting. They do neither. They have no biting mouthparts capable of piercing skin, and they possess no stinger. If one lands on you, it is probably resting or has been drawn in by the carbon dioxide in your breath, body heat, or a nearby chemical cue. The only real nuisance they cause is the damage their acidic body fluids can do to car paint if not washed off promptly.
Seasonal Patterns and How They Affect Feeding
Lovebugs have two major adult flight seasons each year: one in late April through May, and another in late August through September. The timing varies slightly depending on latitude and local weather, with flights starting earlier in southern Florida and later in the northern Gulf states. Between these flights, larvae are underground, quietly feeding on decomposing plant matter.
The spring flight tends to be somewhat smaller than the fall flight, though both can be dramatic in lovebug-heavy areas. During flight seasons, the enormous number of adults all searching for nectar at once can strip small flower patches quickly, but the impact on plants is negligible given the brevity of the adult phase. Within a couple of weeks, the flight is over, the adults die, and the eggs they deposited hatch into larvae that begin their months-long feeding phase in the soil.
Weather influences both the larval and adult stages. A particularly wet summer produces more abundant decaying vegetation, which supports larger larval populations, which in turn leads to denser adult flights the following season. Conversely, drought can reduce lovebug numbers by drying out the thatch layer larvae depend on. This boom-and-bust pattern explains why some years produce overwhelming lovebug swarms while other years are relatively mild.
How Lovebugs Compare to Other Bibionid Flies
Lovebugs belong to the family Bibionidae, commonly known as march flies. There are thousands of bibionid species worldwide, and most share the same basic life cycle pattern: larvae that feed on decaying organic matter in soil, and adults that feed on nectar or pollen. What makes Plecia nearctica stand out is not its diet but its abundance. Most bibionid flies appear in modest numbers and go unnoticed. Lovebugs, thanks to the enormous stretches of managed grassland and pasture across the southeastern United States, have access to more larval habitat than their relatives typically enjoy. The result is population densities that can reach staggering levels during flight season.
Some bibionid species in other parts of the world have larvae that feed on living plant roots rather than dead material, occasionally causing minor agricultural damage. Lovebug larvae, by contrast, are almost exclusively saprophagous, meaning they eat only dead and decaying tissue. This distinction matters because it means lovebug larvae are beneficial to soil health rather than harmful to crops or lawns. If anything, their activity in the thatch layer helps prevent the buildup of dead vegetation that can smother grass and harbor plant pathogens.
Lovebugs and Lawn or Garden Health
Because lovebug larvae feed on dead plant material in the soil, they are generally beneficial to lawns, gardens, and pastures. Their feeding and burrowing activity helps aerate compacted thatch, speed decomposition, and return nutrients to the root zone. Homeowners in Florida and along the Gulf Coast who notice lovebug larvae in their yard are sometimes alarmed, but these larvae are not eating living roots or damaging healthy plants.
The frass produced by lovebug larvae acts as a natural fertilizer, releasing nitrogen, phosphorus, and other nutrients in forms that plant roots can readily absorb. In cattle pastures, where organic matter from manure and mowed grass accumulates quickly, lovebug larvae can process a significant fraction of the surface litter. Ranchers and farmers in the southeastern states have generally come to view lovebugs as a mild seasonal annoyance in their adult form and a quiet asset in their larval form.
There is no practical reason to try to eliminate lovebug larvae from soil. Pesticide applications targeting larvae are largely ineffective anyway, since the larvae live within a dense thatch matrix that insecticides penetrate poorly. More to the point, killing them would remove a natural decomposition service and potentially worsen thatch buildup problems. The most effective approach to managing the adult nuisance phase is simply keeping a good car wax on your vehicle and washing off splattered bugs within a day or two before the acidic residue etches the paint.
What Happens When Lovebugs Have Nothing to Eat
Adult lovebugs that cannot find nectar do not switch to an alternative food source. They simply run out of energy and die sooner. Since adults carry some energy reserves from the larval stage (stored as fat body tissue accumulated during their months of feeding underground), they can survive briefly even without feeding. But nectar extends their adult lifespan and gives females the energy they need to develop and deposit a full clutch of eggs. A female that emerges into an area with poor flowering resources will likely lay fewer eggs, reducing the next generation’s numbers.
Larvae are more resilient to food scarcity because they are mobile within the soil and can seek out pockets of decaying material. However, if the soil dries out completely or if organic matter is removed (as in very intensively maintained landscapes with no thatch or leaf litter), larvae either die or fail to grow to pupation size. This is one reason lovebugs are less common in highly urban, paved-over environments and more abundant in suburban and rural areas with abundant vegetation and organic debris.
The relationship between habitat quality and lovebug abundance is straightforward: more decaying plant material in moist soil produces more larvae, which produces more adults. Anything that reduces the supply of dead vegetation on the ground, whether drought, fire, or intensive landscape maintenance, suppresses lovebug populations. Anything that increases it, like heavy mowing, leaf accumulation, or cattle grazing on improved pastures, boosts them. This basic connection between larval food supply and population size is why lovebug swarms are a fixture of the Gulf Coast landscape, where warm, humid conditions and lush vegetation create ideal feeding grounds year after year.