The leaf beetles
(family Chrysomelidae) generally have antennae 1/2 their body
length
or less, and are characterized by their bright metallic colors. The
adult beetles feed on
leaves and flowers; the larvae attack roots, eat leaves, or tunnel
within them. Many beetles
of this family are important agricultural pests. There are roughly
1,400 species in North America.
Habitat: Meadows and forest
clearings, roadsides /
Food: Dogbane and other members of the milkweed family /
Life cycle: eggs are laid on the host plant or on
the
ground; larvae tunnel through soil to roots, feed, and pupate in
soil.
Here
is an interesting photo essay on the extreme variability of the
cryptic markings on this species of beetle.
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Milkweed Leaf Beetles
"Plant chemical defenses
can be eaten by herbivores, stored, and used in defense against
predators. To be effective defensive agents, the
sequestered chemicals cannot be metabolized into inactive
products. Utilizing plant chemicals can be costly to herbivores
because it often requires specialized handling, storage, and
modification (Bowers 1992). This cost can be seen when plants
that utilize plant chemicals are compared to those plants that
do not in a situation where herbivores are excluded. Caterpillar
and adult
monarch butterflies
store
cardiac glycosides from
milkweed, making these organisms distasteful.
After eating a monarch caterpillar or butterfly, its bird
predator will vomit and will avoid eating similar individuals in
the future (Huheey 1984). Species that feed on milkweeds are
usually
aposematically colored.
Aposomatic species are those that advertise
their distastefulness by being brightly colored (see
Guilford 1990). Two different species of milkweed bug in the
family
Hemiptera,
Lygaeus
kalmii and
Oncopeltus fasciatus, are thus
colored, with bright orange and black markings."* As you can
see, the milkweed leaf beetle shares the same color-scheme as
the milkweed bugs and the Monarch and Viceroy butterflies.
Predators therefor are thought to shun any insects with these
colors.
*From The Wikipedia "Herbivore
adaptations to plant defense."
Leaf
Beetles in Copulo
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