Eristalis tenax
The hoverfly that mimics bees and supports pollination
Overview
Eristalis tenax is a species of hoverfly from the Syrphidae family, commonly known as the drone fly or flower fly. It closely resembles a honeybee, which is a classic case of Batesian mimicry—gaining protection from predators by imitating a more dangerous species. Despite its appearance, E. tenax is harmless and lacks a stinger.
Distribution and Appearance
Originally native to Europe, this species is now widespread across the globe, thriving in urban, rural, and wild environments. Adults have a stocky, hairy body with yellow and black markings, large compound eyes, and clear wings. Their bee-like flight and flower-visiting behavior reinforce the illusion of being a stinging insect.
Ecological Role
Eristalis tenax plays an important role in pollination. As adults feed on nectar and pollen, they inadvertently transfer pollen from flower to flower, helping various plants reproduce. In times of declining bee populations, these flies serve as valuable supplementary pollinators in ecosystems and agriculture.
Larval Stage
The larvae, known as rat-tailed maggots, are adapted to live in stagnant, oxygen-poor water rich in organic matter—such as sewage, compost pits, or decaying plant material. They possess a long, snorkel-like breathing tube that allows them to remain submerged while still accessing air.
Life Cycle
Females lay eggs near organic-rich water sources. After hatching, the larvae develop in these semi-aquatic environments before pupating and emerging as adults. The entire life cycle can be completed in a few weeks, allowing for multiple generations per year in suitable climates.
Scientific and Environmental Interest
Eristalis tenax is often used in environmental studies as a bioindicator due to its presence in various habitats, including polluted areas. Its mimicry, adaptive larval form, and ecological role make it a subject of interest in entomology and conservation biology.