Chris Chafer wrote up figbirds eating Christmas beetles and I've
subsequently seen it myself. I have often seen remains of related
beetles (Scarabidae) in pellets of Boobooks, so assume that they'd eat
Christmas beetles, too.
I concur with Ian Temby re the relative impacts of parasitic insects and
predatory birds on beetle numbers, and the need for restoration of
conditions favouring the parasites. Christmas beetle superabundance is a
symptom of simplified ecosystems!
As to how the wasps find beetle larvae, a good question. I suppose they
operate in a manner similar to that of the ichneumonid wasps that
parasitise 'lawn grubs'. The latter eat grass roots and are usually in
the root zone of grasses, i.e. close to the surface but pretty well
concealed. Their presence in a lawn is heralded by patches of dead grass
( very trying for those folk who seek perfection in a lawn), followed in
a week or two by a noticeable increase in the numbers of slender orange
wasps buzzing low over the lawn. Female wasps are equipped with a long
ovipositor at the end of their abdomen and can be watched pushing this
into the lawn to pierce and deposit an egg into a located grub... how
exactly do they locate the grub? I don't know - anyone else got the
answer?
Richard
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+----------------------------------------+
Richard Johnson
Habitat Case Studies Project Officer
Qld Parks & Wildlife Service
Southwest District
Tel: (07) 4622 4266 Fax: (07) 46 22 4151
E-mail:
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