Friday, September 4, 2009

Milkweed Bugs

An early morning pileup of immature Milkweed Bugs. Given the abundance of Butterfly Milkweed this year, it’s not strange that the bugs that feed on them are also here in large numbers. The nymphs congregate to form a large mass during the night and these are just beginning to stir with the warmth of the rising sun.

These bugs are usually abundant on milkweed pods during late summer. They are seed eaters and they specialize in milkweed. One of my college entomology projects was to raise these bugs and I ended up raising three generations and several thousand bugs.

A pair of mating adults. These are true bugs with the piercing straw-like mouth parts. You can see the mouth stretching beneath the head and thorax of the upper bug. The small dots on the skin of the milkweed pod are scars created by the bug penetrating the pod in search of seeds. It takes a long mouth to reach down into that pod.

But how do the tiny nymphs feed? They are equipped with extra long mouth parts. The mouth on this little guy stretches the length of the body. It looks just long enough to reach the seeds inside the pod.

Like all bugs, molting is a part of growing. Shedding the old skin didn’t take these guys more than a couple minutes. The hardest part seemed to be pulling that long mouth free of the old skin.

In the lower right of this picture is a mating pair of Milkweed Bugs. In the upper right is a lone male that has been slowly stalking the mating pair.

With a final rush, he closed in and aggressively pushed and shook the other male. The couple broke apart and the intruding male chased off after the female. The female doesn’t seem impressed by any of this macho activity.

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