Insects of Southern Australian Broadacre Farming Systems - Grains ...

WASPS, BEES & ANTS (Order Hymenoptera)
Hymenoptera - hymeno (membrane); ptera (wing)
The Hymenoptera is divided into 71 families and contains
about 15,000 species in Australia. The Hymenoptera is
divided into two suborders - Symphyta (sawflies), which
have no distinct waist and Apocrita (ants, bees and
wasps), which have a distinct waist. This order includes
harmful, as well as some of our most beneficial insects.
Hymenopteran habits can vary considerably: some are
predaceous; some parasitic; some cause plant galls;
some feed on plant foliage and others, like honey bees,
live on plant pollen and nectar.
Wasps are important as parasitoids of broadacre pests
and are the only group covered in this section. Bees are
well known as important pollinators of crops and are
frequently seen in flowering crops, such as canola during
spring. Ants may also be abundant, particularly during
the warmer months of the year, and may play a role
as scavengers or in seed dispersal and burial. Sawflies
include the ‘spitfire’ grubs which can occasionally be
seen in clusters feeding on some native trees.
Main characteristics
Larval form
Most are legless (maggot-like) and differ from similar
looking fly maggots (Diptera) as they generally have
visible chewing mouthparts and a developed head
region. Larval forms of the parasitoid wasps are rarely seen
in broadacre crops because they are generally concealed
within the bodies of the prey from which they are feeding.
Legs are present in some hymenopteran larvae, such as
sawflies. Sawfly larvae look similar to moth caterpillars
(Lepidoptera) because they have numerous abdominal
prolegs, but they are more fleshy in appearance and do not
have specialised hooks (crochets) at the base of prolegs.
Adult form
Can be winged or wingless insects. Winged species
have two pairs of membranous wings with relatively few
veins. The forewings are always slightly longer than the
hind wings. The body of wasps, bees and ants are usually
identified by their characteristic narrow waist or the
constricted area that appears to separate the last two
body segments (the thorax and the abdomen). Sawflies
have wide waists.
Mouthparts are formed for chewing (e.g. adult wasps) or
can be modified for sucking (e.g. honey bees). In females,
the abdomen ends in an egg laying tube (ovipositor)
that is often prominent and can be modified to a stinger
or a saw-like organ in some species.
Lifecycle
Complete metamorphosis.
Lifecycles can vary considerably between species. Wasp
parasitoids have a lifecycle that coincides with their host.
In general, eggs are either injected into the host prey or
attached to the outer body. The larval stage feeds on
their host, which is often killed in the process. Larvae
that feed internally either emerge from their host to
pupate (e.g. braconid wasps), or emerge from the host
as adults (e.g. aphid parasitoids). Different species can
attack different stages of the host’s lifecycle.
Many species are colonial and are fed by members of
the colony. Adult wasps mostly feed on nectar and
honeydew.
Groups (families) relevant to broadacre
cropping
Predatory wasps (F: Ichneumonidae and Braconidae):
Small to large wasps, including Diadegma semiclausum, a
larval parasitoid of diamondback moth. Most beneficial
wasps that attack moth larvae and aphids associated
with broadacre crops belong to these two wasp families.
Major species are covered in detail in this section on
pages 84-88.
Bees (F: Apidae): This family includes the introduced
honey bee Apis mellifera, but also many native species
that are important plant pollinators and may be seen
visiting flowers.
Ants (F: Formicidae): All ants belong to the one family.
Worker ants, soldiers and males are commonly seen
and in some species the queen is also visible. The
feeding habits of adult ants can vary and may range
from specialist to generalist predators, scavengers
and omnivores, to seed-eaters, fungus or honeydew
feeders. Some ant species play an important role in seed
dispersal.
SECTION 4 COMMON Pest, Beneficial AND EXOTIC Species
81
Insects of Southern Australian Broadacre Farming Systems Identification Manual and Education Resource © 2012