Grapevine Beetle – Pelidnota punctata
RIP Grapevine Beetle. These big beetles always seem to be on their last legs when I find them
The grapevine beetle is a member of the subfamily Rutelinae of the Scarab beetle family. These potentially destructive beetles are known as shining leaf chafers. Adult chafers eat the leaves and flowers of many deciduous trees, shrubs and other plants, but rarely cause any serious damage. However, their fat, white grubs (reaching 40-45 mm long when full grown) live in the soil and feed on plant roots, especially those of grasses and cereals, and are occasional pests in pastures, nurseries, gardens, and in grassy amenity areas like golf-courses. The injury to grassland and lawns results in poorly growing patches that quickly turn brown in dry weather; the grubs can be found immediately below the surface, usually lying in a characteristic comma-like position.
The grubs sometimes attack vegetables and other garden plants, e.g. lettuce, rasberry, strawberry and young ornamental trees. Injury to the roots and rootstock causes small saplings and tender tap-rooted plants like lettuce, to wilt suddenly or to show stunted growth and a tendency to shed leaves prematurely. Plants growing in rows are usually attacked in succession as the grubs move along from one plant to the next. Chafer grubs feed below ground for 3-4 years before changing into adult beetles.
One thing I find interesting about scarab beetles – they react to a camera flash by flinching and quickly furling their antennae. Not many insects even notice a camera flash; some jumping spiders are notably flash-averse.
Many scarabs have beautiful metallic colors. The scarab beetles’ antennae are distinctive, clubbed and tipped with leaflike plates called lamellae, that can be drawn into a compact ball, or fanned out when sensing odors. The front tibia are evolved for digging. The C-shaped larvae, called grubs, are always pale yellow or white. Both adults and larvae are nocturnal. Many scarabs are scavengers that recycle dung, carrion, and decaying vegetable matter. Others are agricultural pests (i.e. the Japanese beetle). The scarab family has 1300 North American species.
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