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.