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Beneficial Insects and Spiders
by Marg Fleming
August 11, 2000

Many gardeners are making a conscious effort to curb their use of chemicals for the welfare of the environment. Manufacturers have complied by increasing the selection of safe products. Soap sprays, diatomaceous earth, compatible bacteria (BT), and companion planting techniques are all gaining a wider popularity in the wake of a growing concern for the Earth.

As chemicals are gradually eliminated from your gardening routine, you will initially find that the populations of common pests such as aphids will increase. Coping with this initial population explosion can really test your sincerity in restricting your use of pesticides. But be patient. Soon the populations of other less prolific insect species will also increase in response to the healthier environment. But these are the “good guys” of the insect world. They will target and consume your plant pests.

An insect that has recently gained notoriety is the common lady bug. This colourful beetle has red wing covers with black spots. This showy cape parts before flight to expose the delicate wings that propel the lady bug to its next eatery. The main course – aphids.

The obvious adult lady bug is voracious, consuming thousands of aphids during its lifetime. The beetles wander up and down plant stems searching for destructive, soft-bodied aphids, and quickly consume them. But less obvious and perhaps even more violently predacious is the lady bug larva.

This immature worm-like form of the lady bug is about 5 mm. Long and deep charcoal grey in colour. Its body resembles a tiny accordion often patterned with one or two orange segments. It moves quickly over plants by its six short legs (typical of insects), which are located towards the head. Its appetite is seemingly insatiable as it moves from one aphid to the next. Be aware that these immature insects are beneficial to your garden. They are meat eaters, not vegetarians.

As far back as the Middle Ages, lady bugs were dedicated to theVirgin because of their stunning beauty and practical use. Hence “Lady bug”.

On nearby ponds it is worthwhile to spend some time observing dragon flies. They and their close kin the diaphanous damsel flies and iridescent turquoise darning needles all wage war on biting flies. These choppers of the insect world zero in on winged pests and snatch them from the air with a fiercely sharp, extendable lower jaw. They cleverly hover around people near the water, knowing that their main meal considers us a prime target.

Often confused with insects are eight-legged spiders. As insect populations increase, spiders become more obvious. Crab spiders (also called golden rod spiders or flower spiders) can alter their appearance slightly to match the colour of the flower on which they “hide” for hapless insects. In full view and with outstretched “arms” the clever spider in yellow camouflage will sit on the yellow centre of a daisy, then clutch and kill visiting insects. White spiders conceal themselves on or under white petals preparing for rarely unsuccessful sneak attacks on unprepared pollinators. I have seen one such spider, white in colour, hiding in the centre of a double pink peony. Down each side of its abdomen he sported two beautiful peony-pink blotches, an exact match for the flower in which he was concealed.

As fearsome as they look, curious robber flies dart lightly on the breeze, deadly only to pesky flying insects such as deer flies.

Get to know the beneficial insects and spiders in the garden. Be able to recognize both mature and larval forms. A comprehensive handbook of insects and spiders makes an educational and thoughtful gift for anyone wishing to increase their environmental awareness.

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