Wednesday, 17 January 2018

Tailed Emperor Caterpillars

As summer has warmed up and butterflies have become more abundant in the garden I have been watching for Tailed Emperor Charaxes sempronius females visiting or laying eggs on the Persian Silk Tree in the garden. I found a hatched butterfly there last year, so wanted to see any caterpillars.

See: the adult here

I haven't seen any butterflies yet this year, but at least one has laid eggs while I wasn't watching. I found chewed leaves the other day and I have been out at night watching the caterpillars since. They are mostly nocturnal feeders. Although I did see one feeding at about 1100 hr one day.

There are six of these caterpillars on the tree at the moment and they are all at this large stage. I never noticed any chewed leaves when they were small yellow instars.

There are many species of caterpillar which adopt defensive postures, curl up, or drop off their branch whenever they are approached by a potential predator, like me, but these didn't do that. They simply carried on eating or walking along a branch while I watched them. The four pairs of prolegs on the abdomen can be clearly seen in this photograph, with the pair of claspers on the last tail segment. The prolegs have tiny, tiny hooks on their tips for hanging onto vegetation.

Their heads are adorned with these marvelous horns. I watched an ant wander close to one and it faced it off, presenting its horned head-plate at the ant, tracing its path as it passed. Not that the ant probably noticed, they follow scents more than vision. But the horns might deter bird predators. And what are those two little horns in the centre. Anyone know?

In this photograph one pair of the true legs on the thorax can be clearly seen, they are segmented with little claws on the end. This caterpillar carried on munching as I clicked away, its mandibles chomping sideways at the leaf with quite astonishing speed and efficiency.

Once they have fed enough, they crawl back along their branches to pre-formed beds. These are silken pads spread on a leaf, or used to hold two or three leaves together. The silk is sticky, and firm on the leaf, and the caterpillars can hold onto it easily. This is important to help the caterpillars stay attached to the leaf when the wind blows. For they certainly bounced about one windy day when I was watching them. They held on effortlessly.

And there they sleep and grow for much of the rest of the night and most of the day, curled up safely camouflaged and with a firm grip of their leaf bed. Isn't it amazing what goes on in the garden.

Monday, 1 January 2018

Wet Scales

First day of the year and a grand day.

I went to Tidbinbilla Nature Reserve outside Canberra to wander around the wetlands. Well, specifically to see platypus as they are such gorgeous animals. That was as good as ever, so then on for a general look around and experience the wildlife.

While scanning the water surface of the ponds, I noticed a little ripple crossing from bank to bank. It was far too small for a platypus wake. It was a little lizard, about 15 cm long, a species of skink I have yet to identify - anyone know?

The lizard swam with a serpentine motion, waving from side to side with its legs tucked into its flanks, not used to paddle.

Farther on I saw another scaly creature in the water, a Red-bellied Black Snake. A beautiful snake and a marvelously adapted predator. This one was creeping up on another small lizard which was basking on the bank. It never got near enough to strike, or perhaps it did not really want to catch the lizard. That snake carried on slowly patrolling along the edge of the water. Then I noticed two more snakes within ten metres of the first. So I moved slowly and grabbed some shots.

Red-bellies are elapid snakes so are venomous, but they not aggressive and I only watched them, not approached them. They approached me while I kept still.

The red scales on their underside are a rich, yet delicate fiery colour. Their scales are always clean and they shone in the sunshine as the snakes slipped through the grass.

The detailed pattern of how the snakes' scales fit with one another is fascinating, exquisite and no more so than around the head.

They constantly flicked their forked tongues out when hunting, scanning the air for chemical clues of where prey might be lurking.

When seen head on, a victim's last view, they always impress me with their focused attention.

Friday, 29 December 2017

December moths on Black Mountain

Another month, another survey of moths on Black Mountain in Canberra with Suzi Bond and Glenn Cocking. And another set of different moth species, all new to me. The one above is a species of Emerald, Chlorocoma melocrossa, Geometridae,  c 3 cm wingspan.

This one, a Triangular Geometrid Moth Epidesmia chilonaria, was not attracted to the lights but was hanging on a grass stem out in the shadows. So low to the ground that I almost stepped on it, a familiar habit of the species. The noticeably long labial palpi protrude as a pointed 'nose' between the antennae, and this one is partially showing some of her yellow hindwing. c 5 cm wingspan.

Not a moth, and not just a smudge on the bark of a tree. This is a case, a sort of tube, a onesie made of silk and pieces of fine dirt, soil, tiny specks of forest litter. And inside is a Psychidae moth caterpillar, possibly Australian Bagmoth Cebysa leucotelus, snug and safe from predators as it crawled up a branch. It feeds on lichen. c 2 cm long.

A side-on view of the same silk onesie. A tiny gap can be seen between the case and the bark. I would like to watch how these caterpillars build such hideaways around themselves as they grow and feed.

Although most of the moths were attracted to the lights and landed on the white sheet next to the lights, I like to photograph them away from the sheet, on nearby trees and shrubs. They make dramatic images, like this a Capusa sp. Geometridae, on a gum tree. c 5 cm wingspan.

This tiny moth wouldn't land on the surrounding vegetation, so I just had to accept a shot of it on the light sheet. I can't pin down this one to species, although it is likely an Oecophoridae. c 1 cm wingspan.

Isn't she so beautiful. This was probably my favourite for the night - I'll have a new favourite next month. I like her black and white socks and the fiery red/orange patch on the back of her thorax. She is a species of Cryptophasa, Xyloryctidae, c 3 cm wingspan.

I would like to find a caterpillar of one of these. They burrow into the stem of their host plant, gather food at night and bring it back to eat in their burrow during the day. But how do I find one, go out at night with a torch I suppose.

Tuesday, 19 December 2017

A long sit

This pair of Tawny Frogmouths have had a bad season. Back on 6th October (seen above) they were together in their nest tree. Unusually, the female was sitting on the nest in the daytime, so I assume that was because she was laying an egg and had not finished before sunrise, so she stayed on the nest during the day. That is usually the male's task.

Sadly, they then took turns, the male sitting on the nest by day, and both for spells at night, for the next nine weeks. They must have had an infertile egg, or possibly two of them, but that would seem unlikely, and very bad luck. They only stopped trying to incubate and hatch it last week, and it is probably now too late for them to try again. When I suspected that they had a dud egg, weeks ago now, when they should have had chicks, I was tempted to climb up and take the egg away from them so that they could go ahead and re-lay. But, I don't interfere with nature, so I left them to be, sad as it is to witness.

The immediate neighbouring pair also had a dud egg, but they did have a viable one too, and they successfully hatched and fledged a chick (a few weeks ago, see above when it had just left the nest). I saw them again last week, with the chick now well developed and almost full grown since fledging on the 7th November.

The remains of their dud egg, the split shell, was lying below their nest on the day the chick fledged. It had already been eaten by an opportunist predator.

Meanwhile, the next pair along successfully raised two chicks. It is only by studying birds closely that we learn what happens to them when breeding. So many different things can go wrong in life.

Friday, 1 December 2017

November Moths

Delexocha ochrocausta - wingspan c2 cm
note the long upward curved labial palps and fringed hind edges to the wings

I was out on another moth foray in the the Black Mountain woodland in November, with Glenn Cocking and Suzi Bond. Between this trip and that in October, there was quite a difference in the species and abundance of moths attracted to the lights. However, as I am simply a beginner in moth identification I was following their guidance, so what I present here is a very short list of the moths seen. All I aim to do is share my experience with others and illustrate the variety of moths, their colours and forms that can be found in one night with a light.

Wingia aurata - wingspan c2 cm
This Golden Leaf Moth has an amazing face as well as upturned hind edge to its wings. The shape and colour probably mimic a fallen leaf or piece of bark. The flash lighting exaggerates the gloss on the wing scales, it would be mat-toned in daylight when at rest.

Termessa nivosa - c2.5 cm
A Snowy Footman - what a wonderful name. This species' caterpillars feed on lichen, algae and moss and live beneath loose flakes of tree bark.

Melanodes anthracitaria - wingspan c5 cm
No common name - most moths do not have one. This is one of the abundant Geometridae species flying that night and its dark grey/black colouring fitted well on a piece of partially burned wood. There are two colour forms of this species, this and a yellow and black type. There are also two colour forms of caterpillar, green and brown. Both colours of caterpillar can come from the dark adults, but only the green from the yellow and black form. I wonder why this has evolved to the benefit of the species.

Sandava scitisignata - wingspan c2 cm
Fungi Snout - all moths should have such character names. The caterpillars of this species feed on fungi. I like mushrooms too.

Idaea costaria - wingspan c1.5 cm
A White-edged Wave - the pale leading edge to the wings, the costa, shows white in artificial light when they flutter and land around it. This is another geometridae, and like most of those species its mottled camouflage colouring blends with the substrate it lands on. In this case, a log with no bark.