Biology Reference
In-Depth Information
Family
CHRYSOMELIDAE
(leaf beetles)
DESCRIPTION
Adult:
6-8 mm long; rather bulbous, the elytra
noticeably expanded towards the hind end; bluish to
violet, with black antennae, tibiae and tarsi.
Larva:
up
to 11 mm long; cylindrical and mainly black.
A very large family of mainly small, leaf-feeding beetles;
adults often rounded, shiny and brightly coloured. The
family includes flea beetles, whose hind legs have
strongly swollen femora and are adapted for jumping.
Larvae commonly feed in exposed positions on the leaves
of host plants, but many attack plant roots or mine within
the leaves, leaf stalks and stems.
LIFE HISTORY
Adults hibernate and emerge in the spring, the females
eventually laying eggs in large, scattered groups on the
fully expanded leaves. Larvae occur gregariously on
both sides of the leaves from June to July, feeding for
about three weeks. At first they browse on the upper
epidermis, but later they bite out holes between the
major veins. Fully grown larvae drop to the ground
to pupate, either on or just below the surface, and
adults appear 1-2 weeks later. These adults browse
on the foliage before overwintering. There is a single
generation annually.
Agelastica alni
(Linnaeus) (
253-256
)
Alder leaf beetle
An important pest of alder (
Alnus
) in mainland
Europe, where infestations are often severe on wild
and cultivated plants; also associated with beech
(
Fagus sylvatica
), hazel (
Corylus
), hornbeam (
Carpinus
betulus
) and lime (
Tilia
).
253
254
253
Alder leaf beetle (
Agelastica alni
).
254
Larva of alder leaf beetle (
Agelastica alni
).
255
256
255
Larvae of alder leaf beetle (
Agelastica alni
).
256
Alder leaf beetle (
Agelastica alni
) damage to leaves of
Alnus
.
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