4.1.3. Bald brood

Lesser wax moths (and to a lesser extent greater wax moths) can cause “bald brood” in infected colonies. Lesser wax moth larvae will tunnel just below the surface of brood cells. The cells are uncapped and the developing bee pupae inside exposed (Fig. 12). This condition can be confused with general hygienic behaviour where adult bees detected disease / pest-compromised brood and uncap the cells. However, bald brood usually occurs over multiple cells in a linear pattern: uncapped brood cells that are adjacent to one another. The line of damage may turn in any direction based on the tunnelling habits of the larva. There may also be wax moth larva faecal pellets on the heads of the developing bee brood.

Fig. 12. The fore- and hind wings of the greater (A – forewing, B – hind wing) and lesser (C – forewing, D – hind wing) wax moths. The forewing breadth is 5-7 mm for greater wax moths. The termen of the greater wax moth forewing is concave while the Cu of the hind wing is 4-branched. The forewing breadth is less than 5 mm for the lesser wax moth. The lesser wax moth forewing termen is convex and the Cu of the hind wing is 3-branched. Figure text and redrawn images are from Ferguson 1987.

Figure 12