Thursday, December 27, 2012

Amphibian parasites

This Myola tree frog (Litoria myola) is a regular visitor into our house. We actually had to move the frog outside on two occasions in recent weeks. We were sure we were dealing with the same individual as we noticed it had a couple of parasitic fly larvae under its skin. We generally don't interfere with wildlife, preferring to observe what we see and let nature take its course, but  in this case curiosity got the better of us, and decided to give the frog a hand and remove the parasites. The parasite is a fly in the genus Batrachomyia (Diptera: Chloropidae) and is apparently not life threatening to the frogs, however, having two large maggots feeding on body fluids beneath your skin cannot be comfortable. The larvae remain under the skin until they are sufficiently developed then crawl out in order to pupate underground.

The larvae maintain a breathing hole to obtain oxygen (marked with arrows in the image below). We were able to extract them through these holes quite easily. The larvae were bright yellow and 10mm long. This frog now has at least two less worries to contend with, although last night I we found it sitting on the driveway right behind the car when we were about to back out. Now it owes us three favours!

The parasite free frog which should heal completely in a matter of weeks.

One of the two Batrachomyia sp. larvae which were removed from beneath the frog's skin. The head has two hook-like appendages while the forked tail end remains close to the hole in the skin in order to breath.
Each larva remains under the skin until it is sufficiently developed then crawls out in order to pupate underground. Suprisingly, Hoskin, CJ and McCallum, HI (2007) found no evidence that Batrachomyia parasitism impacts on the body condition of these particular frogs, however, another study on several smaller species of frogs did show measurable impact on smaller specimens.

Saturday, December 8, 2012

Christmas beetles arrive

Christmas beetles have made a welcome appearance to our lights over recent nights, the photos below are beetles that appeared tonight.

This attractive beetles belong to the Scarabaeidae family and are in the genus Anoplognathus. We have over thirty species of Christmas beetles in Australia, many are found along the east coast. In some regions they have become more abundant where land clearing has provided additional grasslands which host the beetles' larvae.

The life cycle of these beetles is the same basic cycle as most beetles. In this case, eggs are laid underground in grasslands adjacent to eucalypt trees or forests. The larvae feed upon grass roots and their growth is dependant on soil temperature. Those in warmer climates may emerge a year later, whilst those in cooler regions may spend two years underground. The larvae are crescent-shaped with a pale, reddish-brown head and three pairs of legs, but can be quite difficult to distinguish from other beetle larvae.
A green Christmas beetle, Anoplognathus smaragdinus
The face of Anoplognathus smaragdinus
After pupating, the adults time their emergence with warmer conditions and are also stimulated by rainfall. Different species will emerge at different times throughout the summer; perhaps to avoid direct competition. Other factors can influence the exact timing of their emergence, such as seasonal variations in weather patterns. Most Christmas beetles emerge from November to February, but as we know, many appear in late December.
Anoplognathus porosus 
Christmas beetles are good flyers and can cover distances of several kilometres. Many fly at dusk, but they are often attracted to lights after dark and can end up buzzing around the front porch.

Anoplognathus porosus about to take off

Anoplognathus porosus in flight

Wednesday, December 5, 2012

Colourful katydid nymph

This is Kurandoptera purpura, and older nymph of the katydid featured as a hatchling recently. This individual was found locally upon citrus, and although it has outgrown the ant mimicking phase of its lifecycle it still behaves quite unusually for a katydid. It vibrates its antennae in a rapid tapping-like motion, similar to the way many wasps do. Rather than moving in a 'swaying' leaf-like manner, it moves in faster erratic bursts, which is quite wasp-like also. This nymph was not hesitant at all about moving around during the day. Again this is relatively unusual for katydids. Nymphs of most species are quite inactive during the day, relying on their camouflage to protect them from visual predators such as birds.