Bee moth larvae are the caterpillar-stage young of the greater wax moth (Galleria mellonella), a widespread pest that tunnels through beeswax comb and can destroy stored honeycomb frames in a matter of weeks. These larvae feed on beeswax, pollen, honey residue, and cocoon silk left behind by developing bees, making active and stored hives vulnerable to serious structural damage.
What Bee Moth Larvae Are
The greater wax moth is found on every continent where honeybees are kept. It’s a holometabolous insect, meaning it passes through four distinct life stages: egg, larva, pupa, and adult. The larval stage is the one that causes problems for beekeepers, because it’s the only stage that actively feeds on comb.
Adult wax moths have degenerate mouthparts and cannot eat at all. They live just 7 to 30 days, with males outlasting females. Their sole purpose as adults is reproduction. A single female can lay hundreds of eggs in cracks and crevices inside a hive or on stored comb, and the larvae that hatch do all the damage.
How To Identify the Larvae
Freshly hatched bee moth larvae are tiny, about 1.4 mm long, with a translucent to whitish body. The head stands out: it’s a shiny pale brown with dark black eye spots and heavily hardened mandibles built for chewing through wax. Each larva has three pairs of true legs near the head and five pairs of fleshy prolegs along the abdomen.
As the larvae grow through successive molts, they become more opaque and eventually take on a grayish or dirty white color, sometimes with a slight pinkish tint. Fully grown larvae can reach roughly 25 to 30 mm. You’ll usually spot them before you see them individually, though. The telltale signs in a hive or on stored frames are silk-lined tunnels bored through the comb, along with dark frass (droppings) and webbing matted across the wax surface.
Life Cycle and Timing
The entire life cycle, from egg to adult, takes roughly 30 to 90 days depending on temperature, humidity, and available food. Warmer conditions speed everything up dramatically. In a heated storage building during summer, a generation can turn over in about a month. In cooler conditions, development slows to a crawl.
The pupal stage alone lasts anywhere from 8 to 50 days based on ambient temperature. Larvae spin a tough cocoon, often gouging a shallow depression into the wooden frame to anchor it. These cocoon scars on woodenware are a lasting sign of past infestations even after the moths are gone. Because development accelerates with heat, bee moth larvae are far more destructive in warm climates and during summer months. Cool storage below about 40°F (4°C) effectively halts their development entirely.
Why They’re a Problem for Beekeepers
In a strong, healthy colony, worker bees patrol the comb and remove or kill wax moth eggs and small larvae before they gain a foothold. The real danger comes when colonies are weak, recently lost their queen, or have died out, leaving comb unprotected. Stored frames of drawn comb waiting for the next season are especially vulnerable.
Once larvae establish themselves, they tunnel through the midrib of the comb, destroying cells and leaving behind a mess of silk, frass, and chewed wax. A heavy infestation can reduce an entire super of drawn comb to a webbed, unusable mass. For beekeepers, drawn comb is one of the most valuable assets in the apiary, since bees expend significant energy to build it. Losing frames to wax moths means colonies must rebuild comb from scratch the following season, which cuts into honey production.
Controlling Bee Moth Larvae
The most reliable non-chemical control is cold storage. Keeping empty frames in a freezer or unheated space where temperatures stay consistently below 40°F stops larvae from developing. A hard freeze at 0°F for at least 4 to 5 hours kills eggs, larvae, and pupae already present on frames. Many beekeepers cycle stored comb through a chest freezer before putting it into long-term storage.
Good ventilation and light also discourage adult moths from laying eggs. Stacking supers with spacers that allow airflow, or storing frames in well-lit areas, makes the environment less hospitable. Strong colonies are the best in-hive defense, so keeping hives queenright and avoiding excess empty space inside the hive box reduces vulnerability.
Biological Control Options
The U.S. Environmental Protection Agency has moved to register a product containing a naturally occurring soil bacterium, Bacillus thuringiensis subspecies aizawai (Bta), specifically for use inside beehives. This bacterium produces a crystallized protein that is toxic to wax moth larvae but does not harm bees, humans, or other non-target organisms.
To use it, beekeepers apply a diluted solution directly to empty honeycomb frames before putting them into winter storage. It’s a one-time treatment per storage cycle. When wax moth larvae attempt to feed on treated comb, they ingest the protein, which attaches to the lining of their gut and eventually causes it to rupture. The product is designed for both commercial operations and hobbyist beekeepers, offering a targeted alternative to chemical fumigants that have traditionally been used to protect stored comb.
Other Uses for Wax Moth Larvae
Despite their reputation as pests, bee moth larvae have value outside the apiary. They are widely sold as fishing bait under names like “waxworms,” prized for their soft body and high fat content that attracts panfish, trout, and other species. They’re also a popular feeder insect for pet reptiles, amphibians, and birds.
In scientific research, Galleria mellonella larvae have become a surprisingly important model organism. Their immune system shares functional similarities with the innate immune response in mammals, making them useful for studying bacterial infections, testing new antimicrobial compounds, and screening drug toxicity, all without the ethical and cost barriers of mammalian testing. Researchers have also studied these larvae for their ability to break down polyethylene, a common plastic, though practical applications for waste management remain early-stage.