An an amazing ecosystem has developed for fauna in the Park. Birds, frogs, native rats, lizards, possums, yabbies, a myriad of insects and fungi made their way to the Park attracted by the food and shelter that 300 locally indigenous plant species offer. A complex food chain is becoming apparent. Worms and fungi break down the hundreds of truckloads of mulch, building topsoil. Trees mature, produce food for insects and shelter for birds and smaller plants. Two years of good rain and stormwater from our neighbours has improved water quality in the lakes and the number and variety of land and water-dependent birds increases every year.
Here some examples of our fauna
- Our monthly bird surveys regularly record almost 1,000 individual birds and ~50 species. The total number of species observed in the Park since 2007 stands at 80 water-dependent birds and raptors, and 75 land-based bird species, total 155 (See our Fauna pages for details and current list of bird species: Westgate Park bird species list by AMcCutcheon)
- Ring and brush-tail possums and Rakali (native water rat) have been seen. Snake-necked Turtles breed in the Park and are often seen in the Large Lagoon. Yabbies are in the Dam. Tiger snakes, a Blue-tongued Lizard, Marbled Gecko and skinks are occasionally seen. The Spotted Marsh Frog and the Common Froglet are usually heard calling in our smaller wetlands
- Dragonflies, damselflies, butterflies and moths and their larvae are numerous and diverse, as are spiders. Scale, galls, psylids, bugs, beetles, flies, wasps, midges, bees, aphids, sawflies, springtails, ants and many more are now part of the food chain.
See our Fauna pages for more species.
Mosquito fish were introduced in the main freshwater lake some years ago and these feed on frog spawn and tadpoles so there are few frogs in and around the larger lakes. However, the Spotted Marsh Frog and the Common Froglet are thriving in other wetlands if their calls are anything to go by. The frog spawn (above left) that appeared in the newly established Windmill Soak is probably that of the Spotted Marsh Frog which lays its eggs in water surrounded by plants. The tiny Common Froglet (above right) was found in a wheelbarrow of the compound. Its eggs are attached to leaves and twigs and its tadpoles take 3 months to metamorphose.
Because of its long period of isolation, Australia has a unique collection of insects and spiders, some species surviving the last 400 million years. Indeed Australia’s fauna is dominated by these invertebrates and they play a major role in almost every terrestrial and freshwater environment.
Dragonflies and Damselflies
Moths and butterflies
There are around 250,000 species of moth and 20,000 species of butterfly world-wide, many yet to be described. Here is how you tell which is a moth and which a butterfly:
- Moths have feathery antenna – butterflies have smooth antenna with a club shape at the end.
- Moths tend to have short, fat and very hairy bodies, butterflies have smoother, more slender bodies with less hair.
- Moths are usually a dull colour, butterflies brightly coloured.
- Moth caterpillars spin silk cocoons in which to pupate. Butterfly caterpillars turn into exposed pupa – a crysalis
- Moths are active at night, butterflies during the day
The Australian Admiral – Vanessa itea butterfly is common in Southern Australia, appears in early spring and can produce several generations in one season. Eggs are domed, green, strongly ribbed, laid singly or more often in pairs on the foodplant. The larvae are brown, greyish green or yellow with paler stripes on top and along the sides, the pupa are brown with darker markings, sometimes with silver or gold spots.The adults feed on fermented tree sap, the larvae on stinging nettles.
The Chequered Swallowtail – Princeps demoleus is widespread but not common along the south-east coast. The adults feed on a range of flowers but the larvae feed on plants in the pea family. Eggs are round and yellow, the larvae black with black spines in their early stages, later with orange patches along sides. They are green or yellowish when mature, with black, orange and white patterns and paired short spines front and back. The pupa are green or brown with darker markings.
The Sheoake Moth – Pernattia pusilla – lays its oval white eggs along branchlets of its host; the Allocasuarina verticilata. The spent egg shells shown above. The beautiful caterpillars are well camouflaged with stripes of blue, red and yellow. Note its bright red ‘headband’ and long elegant tufts. In early spring the caterpillars retreat to pupate inside a silk cocoon they spin.
Case moths spin their cases out of silk and attach neatly sized twigs and other material to the outside for protection and camouflage.They spend most of their lives in the caterpillar stage – 1-2 years – and stay inside the cocoon, dragging it from place to place. If threatened they can seal off the entry and cut a new opening once the threat has passed. The females continue to live in their cases after they have pupated into adult moths but the males leave their cases fly off in search of females. These are possibly Stick Case Moths – Clania lewini.
www.arachne.org.au says spiders are the most successful terrestrial predators on Earth and occupy virtually every possible habitat niche. The British arachnologist, W.S. Bristowe established that an English meadow in late summer could support a population of around 5 million spiders/ha. The weight of insects consumed by English spiders each year easily exceeds the weight of the entire human population of England. They are everywhere. They occupy a vital place in the food web and without them we would be literally drowning in insects.
The 2,000 species of spiders in Australia play an immensely important role in the ecology of most environments because of the food they provide to a wide range of predators and because they help to control insect populations. All spiders are carnivores and will prey on anything of appropriate size.
The female Golden Orb Weaving Spider, Nephila sp. weaves a strong, orb-shaped, vertical web with a golden sheen. She rests, head down in the centre, waiting for prey which is quickly wrapped in silk, bitten and eaten or hung for later. The web is semi-permanent. Tiny (6mm) red and brown male spiders live around the edges of the web waiting for a mating opportunity. The female wraps her single egg sac in a mass of golden silk which is then hidden on foliage away from the web, disguised within a curled leaf or sprig of twigs. Predators of orb weavers include several bird species and wasps which land on the web, lure the spider to the perimeter by imitating a struggling insect’s vibrations and then carry the spider away to be paralysed and stored as live food for their young.
The female Garden Orb Weaver, Eriophora transmarina, is only marginally larger than the male and lays 200-300 eggs which are encased in a fluffy silken cocoon and attached to foliage. The spiderlings hatch and are dispersed by floating on the breeze using small silk strands as ‘balloons. They build their own tiny orb webs, wait out the winter, develop during spring and mature in summer. Seen here the female rests during the day with legs drawn close, neatly camouflaged against a reed seed head. The strong, sticky, vertical web is generally constructed in the evening and taken down before dawn. Beneath the spider is the skin of a dragonfly nymph. Honeyeaters are common predators.
There are over 100 species of Garden Orb Weavers in Australia.
The Long-jawed Spider, Tetragnatha family, build small horizontal or inclined orb webs, often near water and are difficult to see because of their habit of resting 0n twigs with all legs aligned. Their long thin legs make it possible to straddle their sparse webs. Their distinctive long jaws are used in mating. The female encases her eggs in a fine white sack attached to a stalk and may rest beside it during the day.
The Leaf-curling Spider, Phonognatha graeffei is also an orb weaving spider, retreating inside a dead leaf it has curled and sealed at the top with silk. Their legs hang from the bottom, feeling the web for the vibrations of prey. Leaf-curling Spiders are usually fat, oval-shaped spiders with red-brown legs and body and a yellow pattern on their backs. The female lays her eggs within another curled leaf which is silked up and hung in the foliage away from the web.
This female Purple-winged Mantid – Tenodera australasiae – is around 100mm long and identified by the white stripe down its abdomen and short purple wings. The males are brown. This species feeds mostly on bees and flies. The female lays up to 400 eggs in a frothy substance which hardens to form an ootheca or capsule which is usually glued onto bark, twigs, fences etc.
Flies, wasps and midges
Most wasp larvae are maggot-like and legless but the Blue-steel Sawfly Perga affinis larvae resemble the caterpillars of moths and butterflies. They now appear in winter in the Park in significant numbers, defoliating many young eucalypts. Adult sawflies have a saw-like appendage which they use to open a leaf and insert their eggs, hence the name. These large black caterpillars feed at night and during the day, cluster together. Bottom right shows a closeup of a head and front legs. They can, if disturbed, release a fluid strongly smelling of eucalyptus oil. This is thought to deter birds and insects that might parasitise them. They move from tree to tree en masse and at maturity, burrow underground to pupate.
The Black Flower Wasp Discolia sorer with its iridescent blue wings, is common to the mainland eastern states. Adults feed on nectar from flowers and the powerful adule female burrows into the soil to find scarab grubs on which it lays an egg after a sting. The larvae emerges and feeds on the still-living grub and the adult emerges next season. They are useful predators of these grubs which are a pest in lawns and they pollinate native plants. They don’t generally sting humans and are not aggressive.
Most flies lay eggs but some can lay live young. Fly larvae or maggots are pale and legless with reduced heads. They prefer moist habitats and generally feed on decaying animal and plant matter, fungi, carrion and dung. Most maggots move away from their feeding medium to pupate and often build a case called puparium. Some flies can transmit disease but others are beneficial because they parasitise pest insects or pollinate plants.
Chironomidae, or non-biting midges, are numerous in the Park. They feed on the sucrose in plant sap and resemble mosquitoes but lack the wing scales and elongated mouthparts. They have spectacular ‘plumose’ or hairy antennae. There are over 10,000 species worldwide. Their nymph stage is aquatic making them an important food source for fish. Adults are consumed by insectivorous birds and bats.
Australia has over 5,600 species of bugs, cicadas, plant hoppers, scale insects, lerps, mealybugs, galls and aphids. Bugs typically suck sap from plants through tube-like mouthparts but can eat seeds and fruit and some are predatory, catching insects and sometimes smaller bugs.
Around the Park these globs of foam appear in Sept/October especially on Goodenia ovata. They are formed by tiny Spittle Bug nymphs which feed on plant sap, consuming so much water and carbohydrate that excess fluid is produced. The nymph uses its body to ‘pump’ bubbles into the fluid and its hind legs to cover themselves with the froth. This shields the nymph from predators, insulates them from temperature extremes and prevents dehydration. In the bottom right photo the nymph is just visible producing bubbles. After <5 moults the adult bug will emerge and lay eggs in late summer.
The Harlequin Bug – Dindymus versicolour is a common sight around Melbourne, often in clusters and mating pairs joined at the end of the abdomens; the larger female <12mm long, usually dictating the direction of movement! They feed on a wide variety of plants and are considered a mild pest to crops. In winter they retreat to dark, shady places and are unable to fly when it is cold. Eggs are laid in spring in undisturbed vegetation or crevices and they hatch to produce similar looking nymphs or instars which go through 5 stages of development and behave in much the same way as the adults. On the far right of the bottom right photo are a pair of what are presumed to be instars of the species.
A Shield or Stink Bug – Poecilometis sp. (above left) feed on eucalypts, hiding under loose bark where they suck up the tree sap. Some Shield Bug species are able to prise open the white shell protecting the lerp psyllid bug and feed on both the nymph and adult as seems to be the case here. The females of some shield bugs stand guard over their eggs and remain there until the eggs have hatched and the nymphs (instars) first moult. The first instar feeds on the bacteria deposited by the adult with the eggs. There are 5 stages of instar; each stage more closely resembling the adult. Wings begin to be developed in the 3rd instar. Instars and adults can produce foul smelling defensive odours.
The Psyllid bug is common in the Park and typically feeds on Eucalyptus camaldulensis – Red River Gum leaves. The white, sugary coating, or lerp, protects the psyllid from some predators however it is a favourite food of pardalotes, honeyeaters, parrots, silvereyes and willy-wagtails and a host of insects such as parasitic wasps. Psyllid nymphs and adults feed on sugar rich phloem from the host plant. They excrete sticky honeydew which crystallises and hardens to form the lerp. Nymphs grow to adulthood under the lerp and, on completing development, the winged adults leave the protection of the lerp and fly to new plants to mate, feed and lay eggs. Sooty moulds can grow on the lerp (above right). Aboriginal people collected these for food and the name is derived from the Aboriginal word; ‘larp’.
Scale insects are mostly parasites of plants, feeding on the sap drawn directly from the plant’s vascular system. Adult female scales are almost always lose their instar legs and become immobile and permanently attached to the plant. They secrete a waxy coating for protection. Adult males can have wings but do not feed and die within a day or two. The first instars or crawl around in search of a place to settle down and feed. These scale have ants acting as herders and carry the young ones to favourable sites to feed in return for harvesting honeydew.
Springtails, family Collembola, date back 400 million years. They are wingless, soft-bodied animals just 1-2mm in length, seen above on fungi. They have a spring like structure under the belly that catapults them into the air. They speed up the process of decay and deposit nutrient-rich faeces back into the earth and they transport spores of mycorrhizal fungi and mycorrhiza-helper bacteria, assisting plant/fungal symbioses. They also help control fungal diseases in plants by consuming mycelia and spores of pathogenic fungi.
Galls appear as a variety of lumpy abnormalities of leaves, buds, stems and roots of plants caused by a reaction of the plant to secretions by insects. These include wasps, flies, beetles, psyllids, coccids, moths and nematodes. Bacteria and fungi can also produce galls but this is less common. The leaves of eucalypts and acacias, are most affected in the Park. Apart from being unsightly however, the damage to the plant is usually minimal.
Typically the adult lays eggs on or in the plant material and the larvae and nymph stages feed from the readily availability of plant sap in the highly nutritious cells on the inside wall. The gall can enclose a single insect but some contain several, each within a separate chamber. The gall provides protection from predators although wasps and other insects can parasitise them.