| 2. Not all insects are pests; in fact, a great many of them are
beneficial to man. Entomologists recognize the good done by
beneficial insects as well as the injury done by harmful ones.
Predators, parasites, and pollinators are the most important
beneficial insects. |
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3. Everyone recognizes the familiar ladybug, or ladybird beetle.
Many species have an enormous appetite for aphids--one of our
most common plant pests. Others prefer scale insects and mites
and are very effective in reducing infestations. |
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4. Ladybug larvae are equally relentless predators. Their
colorful, but ferocious appearance often causes unknowing
gardeners to assume that they must be harmful. Nothing could be
further from the truth. |
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5. The praying mantis is another widely-recognized insect
predator. Nymphs and adults alike lie in wait for an unlucky
insect which strays too close, then strike out to grab it with
their modified front legs. |
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6. Ambush bugs use the same lie-in-wait tactic. Notice that
their front legs are also enlarged and modified. The bright
yellow colors of this species camouflage them in their favorite
hideout--goldenrod flower. |
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7. The larvae of common lacewings are miniature monsters when
viewed at close range. They are deadly enemies of small
caterpillars, aphids, and other soft-bodied insects. |
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8. The lowly ground beetle, so common under logs and debris, is
another friend of man. Both larvae and adults are predaceous and
feed on a wide variety of insects. |
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9. Less common, but still important, robber flies are deadly
enemies of grasshoppers, wasps, and other flies which they
capture on the wing. Some of their prey are as large or larger
than they are. |
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10. Tachinid flies are parasites of other insects. This fly has
laid its small white eggs just above the legs of the caterpillar
in front of it. Upon hatching, the fly maggots will burrow
through their hosts skin and feed on its internal organs. The
caterpillar will die just as the larvae emerge and complete their
development. |
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11. In addition to these flies, many small wasps are important
parasites of other insects. It is very difficult to measure how
important these insects are, but there is no doubt that they are
extremely valuable allies to us. Without their behind-the-scenes
help, our pest problems would be infinitely worse. |
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12. The benefit of insects which pollinate flowers is somewhat
easier to estimate since without them there would be no apples,
pears, cherries, citrus fruit, nuts, berries, coffee, melons,
cucumbers, squash, or many other common foods. Pollinating
insects are estimated to be worth a least 8 billion dollars
annually. Dozens of species of flower flies and wild bees
inadvertently transfer pollen from one flower to another as they
gather nectar to feed themselves and their young. |
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13. The best known pollinator and man s best friend among the
insects in the honey bee. Besides the pollinating services it
renders, this insect provides us with honey which we eat and
beeswax which we use in making candles, polishes, inks, and
cosmetics. It is hard to imagine what life would be like without the natural
pest control, flower pollination, and products provided to us by
these beneficial insects. |
| 14. That concludes Part 5, Beneficial Insects. |
| 15. Credits |