in the diurnal tiger beetles (Cicindelinae), which
catch ants and flies; they include the fastest of all
beetles and have exceptional vision as well as very
strong, sharp mandibles. In the water, the diving
beetles (Dytiscidae) fill the role of ground beetles
as active hunters, feeding on leeches, water snails,
and sometimes amphibians and fish.
In the suborder Polyphaga, which includes the
majority of all beetles, many feeding strategies are
used, and some of the most diverse groups have
made the switch to living plants, but some families
remain primarily predatory. Staphylinidae, as
adults and larvae, are either carabid-like active
hunters of invertebrates (such as the Devil’s Coach
Horse, Ocypus olens) or are predators in specific
environments, for example hunting for fly larvae
in dung or carrion, or ant larvae, while living as
myrmecophiles in ant nests. Most Coccinellidae
are predators of soft-bodied aphids or scale
insects, which occur in such large numbers that
adult or larval ladybugs hardly have to hunt at all,
but simply graze on clusters of barely mobile
prey. This apparently easy food supply comes at
a cost, because the aphids and scale insects are
exposed on the plants, making the ladybugs, in
turn, exposed to other predators; to protect
themselves the ladybugs secrete unpleasant
chemicals, combined with bright warning
coloration to deter their enemies.
left | Coccinella septempunctata
(Coccinellidae) Larva of the Seven
Spot Ladybird, widespread throughout
the northern hemisphere and seen
here grazing on aphids.
below | Dytiscus marginalis
The adult of the European Great
Diving Beetle is as voracious as
its larva. This female has killed
a stickleback Gasterosteus aculeatus.