Greater wax moth (Galleria mellonella)
The greater wax moth is a major pest of the
beekeeping industry in the United States, particularly in the
south. The larvae damage the comb and honey by tunneling into the
wax and leaving behind a mass of webs and debris. Healthy bee
colonies are usually able to defend themselves against this pest
and suffer only minor damage. A strong colony will carry larvae
and adult moths out of the hive and prevent damage. Comb which
has been removed from the hive and stored by the beekeeper, however, is
the most vulnerable to attack. Fumigants, heat, and cold can be
used to protect stored comb.
The wax moth undergoes complete metamorphosis: egg,
larva, pupa, adult. In nature all stages of the wax moth may be
present at the same time and except during cold weather, development is
continuous. The mated female moth deposits small, white, slightly
oblong eggs in masses in cracks away from the light. Eggs hatch
in five to eight days at 75 to 81 degrees F, but may require up to 35
days of incubation at temperatures of 50 to 60 degrees F.
Newly hatched larvae immediately begin to burrow
into the wax. Although the larvae consume a large amount of wax,
it is the impurities and remains of the old bee coccoons which provide
them with most of their nourishment. Because of this, new comb or
foundation is a poor food and is seldom attacked. Depending on
the temperature, larval development ranges from one to five
months - the warmer the temperature, the faster the development.
The most favorable temperature for development is 84 to 93 degrees F.
Young larvae are white, about 1mm long, and very
active. Mature larvae are about 25 mm long, golden-gray or brown
in color, and move much slower. When ready to pupate, the larvae
spin coccoons. Pupation takes from eight days to two months
depending on temperature. The wax moth is about 2 cm long with a
wingspread of 2.5 to 3 cm. The size of an adult varies depending
on the quality of food consumed while a larva. The male is
slightly smaller than the female and has scalloped-shaped wing edges.
Availability: These need to be
ordered and will be available after spring break.
Housing: Keep the larvae in a
glass or plastic jar, about quart jar size, with a cloth lid tightly
secured so no larvae escape. It is best to cover the cloth
lid with a wire mesh screen, as larger larvae can chew through cloth
alone. It is best to keep the culture jar in the dark.
Larvae will burrow into their food and may not always be visible.
The jar should be kept at 84 to 93 degrees F for best results, and
development from egg to adult at this temperature should take four to
six weeks. When the larvae are ready to pupate, they will leave
the medium and pupate in the top part of the jar. The white
coccoons can be easily removed and place into a new container (new jar
with cardboard to climb on) to await adult emergence.
Food: Fill the larval jar
two-thirds full of medium (you will receive medium with your
larvae). Larvae will not need any additional food or water
outside of this medium. Adults do not need food and water
and will live for one to three weeks under these conditions.