This tiny, colorful insect is called a ladybird. In
North America it is known as a ladybug or a lady beetle. Other
countries have their own names for it. Although beetles are not
everyone's favorite insect, ladybirds are generally viewed with
affection. They fascinate children, and gardeners and farmers welcome
them with open arms. What makes them so popular?
Why Popular?
Most
species of this friendly little beetle just love to eat aphids, the
tiny soft-bodied insects that suck the life out of garden and
agricultural crops. Some adult ladybirds can consume several thousand
aphids in their lifetime-and the ladybirds' larvas have huge appetites
too. In addition, the beetle feeds on many other insect pests, and some
even relish plant-damaging mildews. No wonder gardeners and farmers
welcome the ladybird!
In the late 1800's, cottony-cushion scale
insects were accidentally imported from Australia into California,
U.S.A. The pest multiplied so rapidly that it threatened to wipe out
the citrus orchards and destroy the industry. Knowing that in its home
country this scale insect posed no threat to crops, an entomologist
went to Australia in search of the insect's natural enemy. He found it
to be the vedalia, a ladybird beetle. About 500 of the beetles were
shipped to California, and within a year the scale was virtually wiped
out. The citrus orchards were saved.
A Year in the Life of a Ladybird
This
attractive little beetle has a round or oval, dome-shaped body and a
flat underside. Despite having voracious appetites, most species of
ladybirds are under a half inch [12 mm] in length. Hard, shiny wing
covers called elytra protect the delicate flight wings underneath and
give the beetle its colorful pattern. When the insect flies, the elytra
open up and lift out of the way. Although ladybirds are often portrayed
as red with black spots, the approximately 5,000 species actually have
a variety of color and spot combinations. Some are orange or yellow
with black spots. Others are black with red spots. A few have no spots.
Still others have checkerboard markings or stripes.
Many species
live for a year. During winter, adults hibernate in a dry, sheltered
location. Awakening when the days get warmer, they fly in search of
plants infested with aphids. The female, after mating, lays a cluster
of tiny yellow eggs on the underside of a leaf near a good aphid
supply. Each egg hatches into a six-legged larva that looks more like a
ferocious little alligator than a future ladybird. Since the larva
spends its time eating aphids, it soon grows too big for its skin.
After shedding its skin several times, it attaches itself to a plant
and produces a pupal skin. Inside the pupa, the larva continues to grow
until it finally pops out as an adult. At first soft and pale, it
remains on the plant while its body hardens. In a day, its distinctive
markings appear.
Enemies learn to avoid the colorful ladybird.
When threatened, the beetle squirts a yellow, foul-smelling,
horrible-tasting liquid from its joints. Predators, such as birds or
spiders, never forget their first unpleasant encounter, and the
insect's bright color serves as a constant reminder.
A Problem Ladybird
One
species of ladybird, initially used as pest control, is proving
somewhat of a pest itself. The harlequin ladybird, also called the
multicolored Asian lady beetle, lives happily with other species of
ladybirds in its native habitat in northeastern Asia. Because of its
exceptional appetite for aphids and other plant pests, it was recently
introduced into North America and Europe. Unfortunately, it has
endangered native ladybirds by eating all their food. More than that,
when its preferred diet runs out-and without its natural enemies to
control it-the hungry beetle turns to devouring local ladybirds and
other beneficial insects. Entomologists view the future with alarm as
they foresee the extinction of some ladybird species. The harlequin
also makes itself unpopular by gorging on ripe fruit ready for
harvesting and by invading houses in massive numbers in the autumn to
escape the winter cold.
A few other species of ladybirds eat
precious crops instead of insect pests. Happily, however, the vast
majority are a gardener's delight.
Welcome the Ladybird
How
can you attract ladybirds to your garden? Native flowering plants
provide a welcome source of pollen and nectar. A patch of weeds and a
shallow dish of water will encourage them too. If possible, avoid using
chemical pesticides. Some dead leaves left on plants or on the ground
during the winter will provide cozy hibernation sites. Try not to
squash any bugs and eggs you find in your garden. You could be killing
the next generation of ladybirds.
Remember, just a few of these
attractive little insects will help you keep garden pests at bay
without the use of harmful pesticides. If you look after ladybirds,
they will reward you for your care.