Geoscience Reference
In-Depth Information
F
IG. 29
Carabus granulatus
, one of the largest ground beetles (Carabidae). (Drawn by R. C. Welch.)
Earthworms are thought to play an important part in the diet of
Carabus
species,
especially for the subterranean larvae, but both adults and larvae will attack almost
every kind of insect within reach. Much the same applies to the species of
Ptero-
stichus
,
Agonum
and
Calathus
, except that they take smaller prey including spiders,
ants, aphids, springtails and the larvae of flies and other beetles. Experiments have
shown that these ground beetles will consume more than their own body weight of
food in a day. More often, of course, food is a strictly limiting resource which must
be continuously searched for through the litter and soil.
Whereas most of the larger ground beetles are nocturnal, the closely allied tiger
beetles, belonging to the genus
Cincindela
, are active in bright sunshine. They are
often common in open sandy heathland where they may be seen in early spring run-
ning rapidly over the ground and taking short flights. The prominent eyes and huge
scimitar-like mandibles betray their hunting nature, while their equally voracious lar-
vae adopt a strategy of concealment. They lie in burrows up to 30 cm deep waiting
for passing prey which are seized and dragged down in a manner reminiscent of the
