The Nature Writers of Texas

The best nature writing from the newspaper, magazine, blog and book authors of the Lone Star State . . .

Sunday, September 10, 2006

Beetles, Beetles Everywhere
by Ro Wauer

Every year in late summer beetles are commonplace. But this year, probably relating to our odd weather pattern, they seem to be more numerous than usual. At least a dozen species of beetles have been found in my backyard the last few weeks, and it doesn’t take a great deal of searching. For instance, four different species share the overripe watermelon that I have placed on my feeding tray that I use to attract butterflies. The most unusual of these beetles are two long-horn beetles. One is large (about an inch in length) orange and black with equally long orange-and-black segmented antennae. Truly a marvelous creature!

The second long-horned beetle eating away at the watermelon is only half the size of the orange and black species, but is even more colorful. It is blackish blue with numerous tiny yellow, rectangular spots. Its antennae are also the length of its body. I have been unable to specifically identify these beetles, other than knowing that they are both long-horn beetles, members of the family Cerambycidae. The two other beetles sharing pieces of watermelon are more easily identified: June beetle, a heavy-set, rounded insect with a maroon upper side and less than an inch in length, and an eyed click beetle, blackish with tiny white spots and with an obvious pair of eyespots on the head.

Spending a few minutes wandering around the yard will likely turn up several more beetle species. I can expect one or two tiger beetles, scarabs, carrion beetles, stag beetles, darkling beetles, wood borers, lady bugs, weevils, and fireflies, all beetles in the insect order Coleoptera. Why so many kinds? Probably because beetles are the largest order of insects, an amazing diversity of species that utilizes every possible niche. In North America alone there are 115 families and more than 27,000 species. World-wide, there are more that 290,000 of them. Beetles are the largest order of living things, according to Richard White, in his book, Beetles, one of the Peterson Field Guides.

Yet, in spite of the huge variety of beetles, they are fairly easy to separate from other insects. All possess rather horny or leathery front wings (elytra) that usually cover the entire abdomen and nearly always meet in a straight line down the back. Beetle antennae, according to White, are highly variable, "often threadlike, sometimes sawtoothed, or with terminal segments variously enlarged." And beetle mouthparts are designed for chewing.

There are a few insects, however, that can be confused with beetles. True bugs, for instance, can resemble beetles. But bugs (Order Hemiptera) can easily be identified by their overlapping wing covers, not equally divided on their back like beetles. Hoppers, earwings, and roaches have similar characteristics. But only beetles have equally divided wing covers.

White also provides a perspective on the number of beetles within all the families found in North America. Seven families contain more than a thousand members. In declining order they include rove beetles (3100), snout beetles (2432), ground beetles (1700), leaf beetles (1475), scarab beetles (1375), darkling beetles (1300), and long-horn beetles (1100). By anybody's count, that's a lot of insects.

I have not been able to find details of what species occur only in Texas, but White does include the Texas beetle that is a single member of the Family Brachypsectridae (ugh!) occurring only from Texas to California. The Texas beetle is a tiny, flattened, ridged insect that is yellow-brown in color. Sorry, but not all that impressive!

The editor's note in White's book states: "Of the approximately 1,000,000 known species of animals on earth, about three-quarters, or 750,000, are insects. Of these, perhaps two-fifths, or 300,000, are Coleoptera, and therefore a beetle-watcher need never run out of new and exciting finds." One of every living creature is a beetle! My yard beetles prove the point!

1 Comments:

At 7:12 PM, Blogger Laura said...

Hi,

Sorry to post off-topic. I just moved to McKinney, TX from upstate NY. There are two trees in my front yard that I would like to identify. Can you help? I can send description and/or pics.

Thanks,

Laura

 

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