Structure, Appearance and Characteristics Adults:
■ Usually reddish brown, brown and black in colour. Rarely black or metallic.
■ Head with labrum sclerotized and visible externally.
■ Claws equal, fixed, with or without tooth beneath.
■ Head and thorax without horn or tubercle.
■ Size ranges from 3.5 to 40 mm in length depending on species.
■ Antennae short, non-tactile, last 3-7 segments expanded on inner aspect to form a lamellate or ‘club’.
■ Chewing mouthparts. Larvae: ■ Larvae are C-shaped, sclerotized head and well developed legs.
■ Soft and greyish-white in colour.
■ Chewing mouthparts. Life Cycle Complete metamorphosis (egg – larva – pupa – adult) Eggs are large, relatively few and deposited below the surface of the soil in spring or early summer.
Pupation occurs in a cell at some depth in the soil, and the adult after emergence, can remain in the cell until rain softens the soil. Usually 3 larval instars. Generation period rarely less that 1 year and can be up to 4 years. Habitat More common in warmer climates (north-eastern regions of Australia). Larvae live in soil. Some species are nocturnal and shelter in daylight under debris or beneath the soil surface, others can be found in termite mounds (Maechidius spp.), or in enormous numbers on flowering trees (Diphucephala spp.). Also found swarming on flowers in daylight are the Phyllotocus spp. Food Larvae feed on roots and vegetable matter in soil. Adults of most species eat leaves, but a few appear to be adapted to feed on nectar. Pest Status Serious damage can be caused by some species to vegetables, wheat and sugar by larvae, which are commonly known as ‘white grubs’. The ‘grey-back’ is the most serious pest of sugar cane in North Queensland. Some species of adults can cause serious damage to trees through defoliation. Those species that swarm during the day, attracted by bright colours, have more nuisance value.
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