Beneficial Insect — Damsel Fly
Common Name: Damsel Fly
Genus: Nabis
Damsel Bugs are 1/4 to 1/3-inch long and usually yellow to tan-colored although there
are also black ones. Their legs are stilt-like and the front legs are slightly
larger than the other legs to facilitate grasping their prey. Their narrow heads
have large bulbous eyes, long antennae and a flexible, needle-like mouth part
that is tucked under the head and body when not feeding. They have two pairs
of functional wings and some species are excellent fliers.
The nymph stages of damsel bugs feed on smaller prey including mites, aphids,
and eggs. Adult damsel bugs feed on both large and small prey including spidermites,
caterpillars, potato beetles, cabbage worms, corn earworms, and leafhoppers. Damsel
bugs can live up to two weeks without feeding on prey, but if left longerwithout food they
will start eating each other. They tend to eat pest insects, butwill also eat other beneficial
insects, including big-eyed bugs and minute piratebugs.
Adult damsel bugs overwinter and emerge in the late spring. Their favorite
overwintering spots are winter grain and alfalfa fields. When temperatureswarm the
female damsel bug lays eggs in the plant tissue of host plants. Nymph damsel bugs
resemble their adult counterparts but lack wings andgo through five stages of growth
in about two months before attainingadulthood. There are usually several generations
spread throughout thesummer months.
The nymph stages of damsel bugs feed on smaller prey including mites, aphids,
and eggs. Adult damsel bugs feed on both large and small prey including spidermites,
caterpillars, potato beetles, cabbage worms, corn earworms, and leafhoppers.
Damsel bugs can live up to two weeks without feeding on prey, but if left longer
without food they will start eating each other. They tend to eat pest insects, butwill also
eat other beneficial insects, including big-eyed bugs and minute piratebugs.
While damsel bugs play a substantial role in eliminating pests in crops and home
gardens, they are not commercially available. Damsel bugs need coverfor resting and
over-wintering, plants for egg-laying, and plenty of otherinsects for food. They can
be found in field crops such as alfalfa, soybeans,and other legumes, grassy fields,
and gardens.
To encourage damsel bugs in a garden, select a large variety of plants that will
attract many kinds of insects for their food supply. Especially good choicesinclude
caraway, Cosmos bipinnatus, fennel, spearmint, golden rod andmarigold (Tagetes
tenuifolia). Incorporating ground covers, grasses and lowshrubs into the planting
scheme provides shelter and is especially beneficial.