Hawk Moths (Sphingidae) are a family of large, heavy-bodied moths whose caterpillars are similarly large and heavy-bodied, and they get that way by eating voraciously.
The Australian Museum says:
The caterpillar of the Impatiens Hawk Moth, Theretra oldenlandiae, is a common visitor to suburban Sydney gardens. It is most frequently found on Balsams, Impatiens balsamina, I. oliveri and I. wallerana, often eating all the leaves. Some other larval food plants include:
- Arum Lily – Zantedeschia aethiopica
- Fuchsia (any of the garden varieties)
- Grape – Vitis vinifera
The caterpillars are black with yellow spots and strips, and have a thin spine at the end of the abdomen that has a white tip. Mature larvae can reach a length of 7 cm. The larvae pupate in a loosely woven cocoon, which they construct within leaf litter.
… Although they may eat your plants as caterpillars, hawk moths are not considered pests. The adults have an important role as pollinators of many plant species and are the most significant pollinator of papaya (pawpaw) crops.
Hawk moth caterpillars regularly attack just two species of plants in our garden, the Pentas and Madonna Lily, and one or two caterpillars can, and do, strip a plant in a matter of days. The one in my photo was evicted from a white-flowering pentas to give it (the plant!) a chance of survival.
The same site notes that Australia has 65 species of hawk moth (all the adults are shown here, with links to the caterpillars) of the 850 known worldwide. I’m not sure how many of them we have around Townsville but I have photographed adults of seven species and caterpillars of about six in my garden. (Caterpillars are hard to be sure about because each species can have two or three colour forms.)
I only have caterpillar-adult pairs of four species, however, so we have at least eight species altogether: Convolvulus Hawk Moth, Agrius convolvuli; Eupanacra splendens; Grapevine Hawk Moth, Hyppotion celerio; Hippotion rosetta; Daphnis protrudens; White-brow Hawk Moth, Gnathothlibus erotus; Impatiens Hawk Moth, Theretra oldenlandiae; and Macroglossum micacea. Note that most of them don’t even have ‘common’ (i.e. English-language) names but have to get by, somehow, with Latin. I don’t think it bothers them.