An unusual collection on a caterpillar head | Natural Notes | The mail


Many moths have earlier life stages as hairy caterpillars. This one (pictured) is not only very furry, but also has an unusual “hat” arrangement. This “hat” is not litter or excrement of insects that the caterpillar has encountered during its wanderings, nor a parasite. It’s probably not a disguise, as its movement would make the caterpillar more obvious. It is made up of the skins of the caterpillar’s head that have previously moulted, which fall off as the caterpillar grows. A glance at the photo shows the smaller “head” at the top, with the newer one being the larger one attached to the head. The caterpillar molts by first splitting its exoskeleton (skin) along its back. The “skin” of the head falls last. The molted “heads” remain attached to the caterpillar’s body, each adding to the unusual collection. This stacking process seems to happen automatically, without any effort on the part of the caterpillar, and each head is added cleanly vertically, rather than twisted or one-sided. The caterpillar adds to its hairstyle from about the fourth molt, four or five old heads being the maximum normally found. However, there are photographs showing up to six. The caterpillar is the gum leaf skeletonizer, an insect that commonly eats the surface of eucalyptus leaves, leaving behind the “skeleton” of veins but no green tissue. Older caterpillars are able to consume the entire leaf. The caterpillar – measuring about 25 millimeters – is seen occasionally here, but it doesn’t seem common. Although it is said to be easy to find by examining the skeletonized leaves, it is often missed or passed by without interest or attention. Occasionally the caterpillars occur in plague proportions, defoliating patches of forest, although this is rarely seen around Ballarat. The long hairs grow in tufts and can cause skin irritation when handled. The moth is mottled gray, with some dark wavy lines. Its wingspan is about 25 mm. BIRD GROUP Birdlife Ballarat Group’s recently finalized program for the coming year includes talks on mighty owls, birds of prey, the search for the princess parrot in the Australian interior, Indonesian birds and birds of the south coast of New South Wales. Meetings are held monthly. Monthly outings are scheduled for Newstead, Colac, Castlemaine and other locations closer to Ballarat. A spring camp is planned in the Oyen region. The group recently visited the Avoca area and learned about the birds of the Torres Strait. For more information about Birdlife Ballarat Group and its activities, telephone 0408 452 058. This unusual butterfly was found inside. It’s a pretty little butterfly. DV This is a tiger butterfly, or alternate footman. It is the adult of the small hairy black or dark gray caterpillars that sometimes appear indoors in summer. Caterpillars can cause severe allergic reactions when their stinging hairs come into contact with some people’s skin. There are several species of foot butterflies. The wingspan of this one is about 30 mm. The caterpillars feed on lichen. They have been a constant summer nuisance in homes in Wendouree and other parts of Ballarat for many years, presumably feeding on lichen on the roof and moving indoors to shelter from the scorching sun. The alternate footman is a native insect. Its scientific name is Tigrioides alterna.


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