Syrphid Flies
Syrphidae
📖 Description
Syrphid flies are among the most important beneficial insects in both agricultural and garden settings, serving a dual role as pollinators in their adult stage and as voracious aphid predators in their larval stage. A single syrphid fly larva can consume hundreds of aphids during its development, making them extremely effective biological control agents. The adults are important pollinators, visiting a wide range of flowering plants and sometimes matching or exceeding the pollination efficiency of bees for certain crops. Their bee-mimicking appearance is a remarkable example of Batesian mimicry, deterring predators despite their complete harmlessness.
⚠️ Symptoms to watch for
- Adults hovering around flowers in the garden,Legless larvae found among aphid colonies on leaves,Declining aphid populations in areas with active hover fly larvae,Shriveled, empty aphid skins left behind by feeding larvae,Increased pollination of flowering crops
🩹 Treatment
- Plant alyssum, dill, coriander, and buckwheat to attract adults (organic),Provide shallow water sources and moist habitat for larvae,Avoid broad-spectrum insecticides that kill both larvae and adults,Tolerate small aphid populations to support syrphid fly reproduction
🌿 Organic treatments
- Plant alyssum, dill, coriander, and buckwheat to attract adults
🛡️ Prevention
- Plant diverse flowering species with overlapping bloom periods,Include sweet alyssum, buckwheat, and phacelia as insectary plants,Reduce or eliminate broad-spectrum insecticide applications,Maintain some aphid-tolerant plants as larval food sources
🪴 Affected plants
- Roses,Vegetables,Fruit Trees,Herb Gardens
🦋 Natural predators
- Birds,Spiders,Assassin Bugs
🌱 Host plants
- Rosa spp.,Brassica spp.,Malus domestica,Lactuca sativa
🔄 Lifecycle
- Syrphid flies undergo complete metamorphosis.
- Females lay single white, oval eggs on or near aphid colonies.
- Eggs hatch in 2-3 days, and larvae feed on aphids for 1-2 weeks, each consuming 200-800 aphids before pupating in the soil or on plants.
- Adults emerge after 1-2 weeks and live for several weeks, feeding on nectar and pollen.
- Multiple generations occur per year, with two to five generations common in temperate regions.
- Some species overwinter as adults in protected locations.
📅 Season
- Spring through Fall (most abundant in summer)
🔎 Appearance
- Syrphid flies, also known as hover flies or flower flies, are bee and wasp mimics with black and yellow striped abdomens that make them appear dangerous, though they are completely harmless.
- They have large, rounded heads with prominent compound eyes that meet at the top in males, and relatively short, clubbed antennae.
- Unlike bees, they have only one pair of wings and no narrowed waist.
- They are exceptional fliers, able to hover motionless in midair and dart with precision.
- Larvae are elongated, legless maggots that vary from green to brown, often semi-transparent, found crawling among aphid colonies.
💥 Damage level
- Low
🔁 Reproduction rate
- Fast
🗺️ Geographic regions
- Worldwide
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