Flies

Order: Diptera
Family: Bombyliidae, Conopidae, Stratiomyiidae, Syrphidae, Tachinidae, Calliphoridae

Beetles

Order: Coleoptera
Family: Anthicidae, Buprestidae, Cantharidae, Cerambycidae, Chrysomelidae, Curculionidae

Description

Flies and Beetles are two diverse insect groups that play a minor role in pollination. Like all insects, flies and beetles have three pairs of legs, antennae, and three body segments (a head, thorax, and abdomen). Morphology is highly variable in both insect groups; especially beetles whose hardened outer wings (called elytra) sometimes display ornate colors and patterns. 

Quick Facts

  • Flies and beetles are insect groups in the families Diptera and Coleoptera, respectively.
  • Beetles are the most diverse insect group, with over 350,000 described species. There are around 30,000 beetle species in the United States.
  • There are over 110,000 fly species in the world. While flies do not sting, species in the families Bombyliidae and Syrphidae are excellent bee mimics. Their appearance helps ward off predators.
flower longhorn beetle

Flower longhorn beetle (Analeptura lineola) visiting a flower.
Ansel Oommen, Bugwood.org

Flies and beetles are insects that play a minor role in pollination. Collectively, there are over 450,000 species in these two insect families. While uncommon, some plant species depend on flies and beetles for pollination.

syrphid flies

Syrphid fly visiting a flower. Some pollinating flies mimic bees to deter predators.
Whitney Cranshaw, Colorado State University, Bugwood.org

midge fly

Midge Fly (family Chironomidae).
Johnny N. Dell, Bugwood.org

bee fly

Bee fly (Bombylius sp.) visiting a flower. Some pollinating flies mimic bees to deter predators.
Johnny N. Dell, Bugwood.org

Description continued

Beetles and flies are considered relatively minor pollinators but there are notable exceptions. For example, cocoa tree reproduction depends on cross-pollination by midge flies! Unlike many plants, the small white flowers of cocoa trees are distributed on the trunk and lower hanging branches. They produce a mushroom-like odor, which is attractive to the tiny flies. Similarly, skunk cabbages emit a foul aroma during blooms. This attracts scavenging flies and beetles, though the flower does not produce any nectar. In addition to producing chemical attractants, skunk cabbage flower coloration resembles dung or carrion and is visually attractive to these insects.

Life History and Habits

  • Flies and beetles undergo complete metamorphosis, meaning they have four life stages: egg, larva, pupa, and adult.
  • Fly larvae are called maggots.
  • Some fly and beetle species have aquatic juvenile stages that develop in freshwater habitats.
  • Beetles have chewing mouth parts; flies have sucking mouth parts. In the case of blood sucking flies like mosquitoes, the mouth part also contains a piercing structure.
  • Both insect groups lay their eggs in a variety of substrates including decaying plant or animal matter, dung, or in the case of some fly species, living animal flesh. These substrates serve as food for larvae.

References

Smithsonian Institution. (n.d.). Beetles (Coleoptera). Smithsonian Institution. Available www.si.edu/spotlight/buginfo/beetle
Smithsonian Institution. (n.d.). True Flies (Diptera). Smithsonian Institution. Available www.si.edu/spotlight/buginfo
United States Department of Agriculture. (n.d.). Fly Pollination. USDA: US Forest Service. Available www.fs.fed.us/wildflowers/pollinators/