Wax moths are common pests that threaten beehives. While their name suggests a simple diet of wax, their feeding habits are more intricate and damaging. This article explores their specific dietary preferences and the significant impact on bee colonies.
The Main Meal: Beeswax and Hive Components
The destructive larval stage of the wax moth life cycle primarily consumes beeswax, especially comb that has previously housed honey, pollen, and developing bees. It is not solely the wax itself that attracts them, but rather the nutritional residues embedded within it, including pollen, remnants of honey, propolis, and the silk cocoons and shed skins left behind by emerging bees. Both the Greater Wax Moth (Galleria mellonella) and the Lesser Wax Moth (Achroia grisella) show a strong preference for these materials. These larvae tunnel through the comb, leaving behind silken webs and feces as they feed. They particularly target darker, older brood combs, which are richer in these nutritional byproducts than new or purely honey-filled combs.
Why Beeswax is Appealing
Wax moth larvae possess unique digestive capabilities, allowing them to break down complex substances found in beeswax and other hive debris. Their gut microbiota aids this digestion. Beeswax itself, though indigestible to humans, contains lipids that provide a significant energy source for the larvae. The protein content necessary for their rapid growth and development comes from pollen and the remains of bee cocoons and larval skins. Honey remnants contribute carbohydrates, supplying additional energy. This rich combination of fats, proteins, and carbohydrates within the hive components provides the complete nutritional profile required for the wax moth larvae to mature quickly.
Consequences of Their Appetite
The feeding activity of wax moth larvae causes considerable damage, particularly within a beekeeping context. As they tunnel through the comb, they destroy its structural integrity, rendering it unusable for bees. Their burrowing can ruin honey stores and spread silken webbing and dark, granular feces, known as frass, throughout the hive. This destruction can lead to the collapse of bee colonies, especially those that are already weak, diseased, or stressed. The tunneling can also result in “bald brood,” a condition where developing bee pupae are exposed as the larvae partly remove cell caps. In severe infestations, the extensive webbing can even trap emerging bees, a condition called galleriasis, preventing them from leaving their cells.