Plecia nearctica

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Geographic Range

Today, lovebugs occur in large populations in every state along the Gulf of Mexico as well as Georgia and South Carolina. Populations of lovebugs also exist throughout Central America. Plecia nearctica was recognized in Texas and Louisiana as early as 1911, but was not seen in Florida until about 1949. (Buschman, 1976; Cherry and Raid, 2000; Thompson, 1975)

Habitat

Both larval and adult lovebugs are found primarily in grass habitats. Plecia nearctica are strong flyers, however, and can be encountered in almost any habitat. They are especially partial to freshly cut lawns, animal pastures, and decaying vegetation. Adult lovebugs have even been spotted several miles off the Gulf Coast (over water), and at altitudes of 1500 feet. (Buschman, 1976; Chambers, 1977)

  • Range elevation
    457.2 (high) m
    1500.00 (high) ft

Physical Description

Lovebugs are sexually dimorphic. Males are much smaller than females, but have larger eyes. Lovebugs have seven to twelve segments on each antenna and have branched wings. Their bodies are mostly black, with a large orange/red area on top of the thorax. (Thompson, 1975)

  • Sexual Dimorphism
  • female larger

Development

Eggs hatch and mature through larval and pupal stages, emerging as adults between 3 and 9 months later.

Eclosion from the pupae takes about five hours for males, and six for females. Within two hours of emerging, both males and females are fully pigmented. (Kish, et al., 1977; Thornhill, 1976)

Reproduction

Plecia nearctica emerge from their pupal stage ready to mate. Males emerge first and hover above the emergence site. Male lovebug swarms consist of large males near the ground, medium males in the middle, and small males farthest from the ground. The large males (closest to the ground) are able to "pair" with the females before the other males. There is evidence of a great amount of male intraspecific competition over females.

Once the females emerge, they fly up through the swarm of males. Males usually grasp females in the air, but always have to "pair" on the ground. Males may also try to "break up" other copulating pairs in order to take the female. Males can separate couples that have not completely engaged their genitalia. If a couple has been paired more than four and a half minutes, they are almost impossible to separate.

During copulation, males face the opposite direction of the female. Lovebugs remain paired for about three days. Because of their short lifespan, lengthy copulation is especially costly for males. Although lovebugs are able to mate more then once, they usually do not. After the male and female separate, the female lays her eggs and dies.

Plecia nearctica are most noted for their copulating method. Males and females are seen flying together, attached at a 180-degree angle. (Thornhill, 1976; Thornhill, 1980)

Plecia nearctica emerge between the months of March and December, with the largest groups emerging in May and September. After emerging, male lovebugs swarm around the nesting site waiting to mate with the females.

Female lovebugs lay their eggs in decaying vegetation and soil. (Kish, et al., 1977; Thornhill, 1976)

  • Breeding interval
    Lovebugs breed only once in their lifetimes.
  • Breeding season
    May, September

After ovipostion, there is no further parental care or involvement.

  • Parental Investment
  • pre-fertilization
    • provisioning
    • protecting
      • female

Lifespan/Longevity

Like many other insects, lovebugs have a short lifespan. After metamorphosis, adult males live from two to five days and adult females up to seven. (Hieber and Cohen, 1983)

Behavior

There is evidence that lovebugs do not move around during the dark hours, and most flying activity can be observed between 10:00 am and 4:00 pm (Thornhill, 1980). Lovebugs wait until the sun comes up and the temperature reaches at least 20 degrees Celsius to begin moving around. In the morning, males begin hovering above the emergence site. Thousands of males have been seen hovering over a single pasture. All males orient into the wind, and wait for the females to begin emerging.

By mid to late-morning mated pairs begin searching for food. Females are thought to control the movement and direction of the pair. Lovebugs fly in searching patterns for food and water throughout the afternoon. Many lovebugs are seen along highways flying aimlessly. Several experiments have shown lovebugs are attracted to the invisible car fumes along highways. This invisible fume trail contains organic compounds that confuse female lovebugs. Females oviposit in decaying organic material, which gives off a very similar chemical signal. Large numbers of Plecia nearctica adults have also been witnessed near traffic lights and gas stations.

Hovering starts again in the late afternoon and continues until sunset. Once it is dark, however, flying stops. Pairs land on vegetation and usually do not move throughout the night. The "dark" hours are spent resting. (Callahan and Denmark, 1973; Chambers, 1977; Hieber and Cohen, 1983; Thornhill, 1980)

Communication and Perception

Because of their short lifespan, quickly finding a mate is important for the success of P. nearctica. Males swarming over nesting sites dart out and "hit" any insect or object that flies in their area. If it has not contacted a female, then the male goes back to hovering. Males use physical contact, visual, and auditory cues to find single females.

Females use chemical scents and visual cues in order to find appropriate locations for ovipositing. (Buschman, 1976)

Food Habits

Adult Plecia nearctica are completely dependent upon nectar and pollen as food. Lovebugs feed during the day, and are thought to stop feeding in the late afternoon. Lovebug larvae use decaying vegetation as a source of food. Emerging lovebugs cannot survive more than 24 hours without food.

Because of the mating position (females and males in opposite directions), it is believed that males do not feed as often as females. (Leppla, et al., 1974; Thornhill, 1976; Van Handel, 1976)

  • Plant Foods
  • leaves
  • nectar
  • pollen

Predation

There are no known species that prey on the early stages of P. nearctica, nor are there any that particularly feed on the adult fly. Lovebugs are considered to be pests to humans. Biologists have tested different fungi on lovebug larva as a possibility of biological control. (Kish, et al., 1977; Thompson, 1975)

Ecosystem Roles

Lovebugs are an introduced species, and do not have many natural enemies. Because of this, lovebug populations continue to grow and move. Many people consider P. nearctica a pest. Methods are being sought to control the populations of these insects. Beauveria bassiana, a fungus, is being considered as a tool in the control of P. nearctica. In testing, Beauveria bassiana, proved to be pathogenic to the lovebug and to cause signifigant mortality among larva and adults. (Callahan and Denmark, 1974; Kish, et al., 1977)

Economic Importance for Humans: Positive

Plecia nearctica lay their eggs in places with dying vegetation. After hatching, the larva feeds on this vegetation. Lovebug larva benefit humans by breaking down dead vegetation and returning it to the soil. (Thompson, 1975)

Economic Importance for Humans: Negative

Adult lovebugs are considered to be a "pain" by many people. They are attracted to highways where they are smashed by passing vehicles. The bodies of lovebugs cause damage to the paint of cars and can cause radiators to overheat. Lovebugs are also attracted to freshly painted surfaces and can be seen in the dried paint of many buildings. (Callahan and Denmark, 1974)

Conservation Status

Lovebugs are not in danger of extinction and are not part of any conservation programs.

Other Comments

Plecia nearctica was first described in Galveston, Texas in 1940.

Humans most likely aided in the quick dispersal of P. nearctica across the Gulf Coast states. Adult lovebugs can easily be transported in cars and their larvae through commercial shipments of sod. (Buschman, 1976; Cherry and Raid, 2000; Thompson, 1975)

Contributors

Sara Diamond (author), Animal Diversity Web.

Sheralyn Chilson (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

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Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

herbivore

An animal that eats mainly plants or parts of plants.

internal fertilization

fertilization takes place within the female's body

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nectarivore

an animal that mainly eats nectar from flowers

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

polymorphic

"many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic. Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.

semelparous

offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

taiga

Coniferous or boreal forest, located in a band across northern North America, Europe, and Asia. This terrestrial biome also occurs at high elevations. Long, cold winters and short, wet summers. Few species of trees are present; these are primarily conifers that grow in dense stands with little undergrowth. Some deciduous trees also may be present.

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

References

Buschman, L. 1976. Invasion of Florida by the Lovebug *Plecia nearctica* (Diptera:Bibionidae). Florida Entomologist,, 59(2): 191-194.

Callahan, P., H. Denmark. 1973. Attraction of the lovebug, *Plecia nearctica* (Diptera: Bibionidae), to UV Irradiated Automobile Exhaust Fumes. Florida Entomologist,, 56(2): 115-119.

Callahan, P., H. Denmark. 1974. The Lovebug Phenomenon. Proceedings of the Tall Timbers Conference on ecological animal control by habitat management: 93-101.

Chambers, S. 1977. Genetic Characteristics of a Colonizing Episode in the Lovebug, *Plecia nearctica*. Annals of the Entomological Society of America,, 70(4): 537-540.

Cherry, R., R. Raid. 2000. Seasonal flight of *Plecia nearctica* (Diptera:Bibionidae) in Southern Florida. Florida Entomologist,, 83(1): 94-96.

Hieber, C., J. Cohen. 1983. Sexual Selection in the Lovebug, *Plecia nearctica*: The role of male choice. Evolution,, 37(5): 987-992.

Kish, L., I. Terry, G. Allen. 1977. Three fungi tested against the lovebug, *Plecia nearctica*, in Florida. Florida Entomologist,, 60(4): 291-295.

Leppla, N., J. Sharp, W. Turner, E. Hamilton, D. Bennett. 1974. Rhythmic Activity of *Plecia nearctica*. Environmental Entomology,, 3(2): 323-326.

Thompson, C. 1975. Lovebugs, a review of the Nearctic Species of Plecia Wiedemann (Diptera:Bibionidae). Coop Econ Insect Rep Anim Plant Health Serv Plant Prot Quar Programs,, 25(8): 87-91.

Thornhill, R. 1976. Reproductive Behavior of the Lovebug, *Plecia nearctica* (Diptera:Bibionidae). Annals of the Entomological Society of America,, 69(5): 843-847.

Thornhill, R. 1980. Sexual Selection within Mating Swarms of the Lovebug, *Plecia nearctica* (Diptera:Bibionidae). Animal Behavior,, 28: 405-412.

Van Handel, E. 1976. Metabolism of the Lovebug *Plecia nearctica* (Diptera:Bibionidae). Annals of the Entomological Society of America,, 69(2): 215-216.