Palp facts
Male Redback Spider
Spiders are remarkable creatures particularly the way they reproduce. In male spiders there is no internal connection between where the sperm is produced and the organ which delivers it to the female, the palp. Palps are two hairy appendages (they look like small legs) that protrude from the front of the spider. Among other things the palp acts as a siphon to collect the sperm from the male abdomen (or from a silk sac into which the sperm is deposited), and as a device to deposit that sperm into one or both female spermathecae (sperm storage containers), where the sperm can remain viable for up to two years.
I was reminded of this when I got a call last week from Michelle at Yea High School wanting to know whether I wanted to come over and photograph some Redback Spiders (Latrodectus hasseltii) outside a science block window. The sperm transferring process sounds pretty straight forward until you look at the size discrepancy between male and female redbacks (see photo below). The standard image of a black spider with a red hourglass marking is that of the female spider. Male redbacks (pictured above left) look entirely different and are way smaller.
Male (left), hidden female’s legs (top centre), egg sac (top right)
Male wrapping up prey
It sounds incredible but it’s not palp fiction.
It is busy in ant world
I am not a rock roller. When looking for invertebrates in the landscape I am reluctant to turn over logs or rocks to find things to photograph. Even if I gently put the rock back where I found it I feel that I am destroying something’s home, let alone the fact that the revealed critters could be squashed. I was therefore a little distressed when moving a load of bricks to find I had disturbed an ant colony, even more so when it was the ‘nursery’.
Uncovering an ant nursery creates a flurry of activity. Ant eggs, larvae and pupae required specific temperature and humidity conditions to develop properly. If those conditions are compromised i.e. someone moving the bricks, the young are quickly moved to an area with the correct conditions.
Eggs, larvae and pupae
The initial role of a worker ant is to look after the young by providing food or transport. As workers mature the tasks change to more energetic jobs like digging and clearing the nest. In the ‘twilight’ of their lives worker ants are given the more hazardous jobs like defending the colony or foraging for food. If they get killed – well, they were old anyway!
I’m glad our local IGA is a safe place to shop.
The lost and lonely
Twitchers (fanatical birdwatchers) lead a life of quiet desperation, always on the look-out for a ‘lifer’ – a bird species they have never seen before. This explains the phenomenon late last year when hundreds of bird-watchers flocked (pardon the pun) to the Werribee Treatment Plant after the reported sighting of a single Paradise Duck (a species rarely if ever seen in Australia) bobbing among the thousands of birds down there. Sometimes however that special bird comes to you.
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Susan who lives just west of Yea last week reported a Magpie Goose (Anseranas semipalmata) on her property and wanted to know if it was unusual in this area. This bird is neither a magpie nor a goose. The binomial name is derived from the Latin anser meaning goose, anas meaning duck, semi meaning half and palmatus meaning webbed – a half-webbed goose-duck, half-webbed referring to its feet.
Today Magpie Geese inhabit wetlands of northern Australia and southern New Guinea where they feed on water-based and land-based plant matter. Their range once extended this far south but due to systematic destruction of wetland habitas for agricultural purposes the bird has long disappeared from this landscape. Attempts have been made to re-introduce populations of Magpie Geese in the south – at Bool Lagoon near Narracorte, S.A. and in the Serendip Wetlands near Lara. The sighted bird could be a member of one of those populations, though still far from home.
So to answer the question, these days the appearance of a Magpie Goose around here is highly unusual. As Geoff our local bird guru said ‘it looks lost and lonely’. It was only around for a day. On the bright side, it may have been scoping out new territory for its mates – Yea Wetlands maybe?
C’arn the blues
A ‘blue’ on Purple Loosestrife
A recent blog described the Hesperiidae family of small butterflies, commonly known as Skippers. They are a relatively unknown group of small, generally orange/brown butterflies. Another relatively unknown family of butterflies is Lycaenidae, the Blues and Coppers, also called the Gossamer-Winged Butterflies. They are the second largest group of butterflies comprising about 30% of known butterfly species. The majority of Lycaenids in Australia exist in tropical areas. There are less than a dozen species in Tasmania. Most commonly around here this family is represented by small blue/grey butterflies which are frequenting flowers at the moment (pictured left).
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Common Grass-blues (Zizina labradus) mating
Ants tending an Imperial Hairstreak caterpillar
The distributions of species are highly localised reflecting the spread of particular plants that the larvae feed on and the relationship many species have with specific ants. Many butterflies of the Lycaenidae family have a beneficial relationship with ants (click HERE to read the previous blog about the Imperial Hairstreak). The caterpillars and pupae have a gland which releases honeydew, a sugar-rich substance secreted by a number of insects including hemipterans such as psyllids and gumtree hoppers. The ants harvest this honeydew and in return offer the caterpillars protection from predators and parasites. In some species the caterpillars enter the ants nest to pupate and the emerging adult has to find its way to the surface.
Even though larger butterflies are more easily seen, a careful look at your flowering plants at the moment will give you ‘the blues’, in a nice way.
Flight of the feather-horneds
For two weeks of the year, the last week in February and the first week in March (give or take depending on the season) the Feather-horned Beetles (Rhipicera sp.) take flight and the air is filled with these large, slow-flying insects (pictured below). The male sports large feather-like antennae which it uses to detect a mating pheromone emitted by the female beetle. The female beetle has simple rod-like antennae.
Little is known about these insects so to repeat a previous blog it is thought the larvae of this beetle are parasitic on the larvae of cicadas. The white patches on the exoskeleton are actually tufts of hairs. I think it is a case of a picture speaks a thousand words!
My challenge this year is to take a picture of the female beetle. Not as impressive in the antennae department but a key part of the story.
More tales from the Swamp Gum
Following on from reporting about the tiny critters inhabiting the leaves and flowers of a local Swamp Gum (Eucalyptus ovata), the insects I was actually searching for also turned up – Flower Wasps. Regular readers of this blog probably think I obsess about Flower Wasps and they are probably right. They are my favourite insect.
As mentioned in many! previous blogs there is sexual dimorphism in Flower Wasps. The male wasp is winged and is much larger than the female wasp. The female wasp does not have wings so to get to the nectar rich flowers at the top of a tree such as a Swamp Gum it has to entice a male to mate with her. During and after that act the male wasp flies to the higher branches to feed on the nectar and the female wasp hangs on for the ride to also feed. It is one thing to read about and know this but it is truly magic to watch it in action. The local Swamp Gum being bent over offers that opportunity as the flowers are near ground level. Pictured below is a male (winged) and female wasp feeding (and mating) at the flowers. After feeding, the female wasp drops to the ground where it searches for beetle larvae on which to lay its eggs.
The vast majority of adult wasps are nectar feeders (and therefore pollinators). Another species turning up to feed at the Swamp Gum is also a regular to this blog, a Gasteruptiid Wasp. Pictured below is a male Gasteruptiid feeding. The female is recognisable by having a white tipped ovipositor about half the length of its body in size. Female wasps lay their eggs in the nests of Blue-banded Bees. They are a regular at the Blue-banded B&B.
This Swamp Gum could be a source from many stories to come – unless the heavy downpour last night washed out all the flowers. Stay tuned.
All creatures small and smaller
Very often we don’t spend the time to stop and smell the roses…or in this case smell the honey. Many eucalypts are flowering at the moment and you can be forgiven for not noticing given the flowers are pale yellow and high up in the trees. Locally there is a Swamp Gum (Eucalyptus ovata) with its crown bent over so that the flowers are at ground level. The heady scent of honey is attracting all sorts of critters, in particular wasps. So I have been staking out the tree to try and photograph some wasps for an upcoming talk.
Whilst sitting and waiting I noticed all manner of small insects also attracted to the rich nectar source. These I would not have noticed (you can get some idea of their size by comparing what they are sitting on) unless I had stopped and watched. Pictured left and below is an Ant Fly (Family Sepsidae), so called because they usually gather in large groups and from a distance look exactly like ants. The adults are nectar feeders. The one pictured is ‘bubbling’, the practice of evaporating all the water out of the nectar so that it can consume more of ‘the good stuff’. These flies are usually found around manure where they lay their eggs. The larvae are efficient composters of it.
Smaller still was this Chalcid Wasp pictured (right) on a eucalypt leaf. Again the adults are nectar feeders. Most species from this family of wasps are parasitoid – they lay their eggs on a live but paralysed host i.e. they are parasitic but resulting in the host’s death. Some species though are termed hyperparasitoid (now focus) they lay their eggs on the eggs of wasps that lay their eggs on a host. Small in size…large in confusion.
I wonder what the term is for a wasp that lays its eggs on the eggs of a Chalcid Wasp?
More Swamp Gum tales to follow!
A prickly story
Just after we put a post about Short-beaked Echidnas on this blog in early January, we discovered an echidna burrow with a puggle (young) in it only 30m from our house, and the adult featured in that post was most likely the mother. We only located the burrow when we noticed a small patch on an old pile of top-soil was moving up and down, as if it were “breathing”. When a bit of soil was brushed away, a creature with short sharp spines was revealed.
Puggle being fed
Puggle’s first outing
After setting up a remote camera, we were able to record the comings and goings of the mother over the next month or so, and occasionally watch her during the daytime. Her visits to the burrow were an average of 4 days apart (maximum of 7 days), and after uncovering the entrance and getting in with the puggle, she spent an average of 2 hours feeding it, before packing the entrance with soil and heading off to forage for ants and termites. With such intermittent feeding the echidna milk is necessarily very rich (imagine being fed only once a week!) and the puggle ingests up to 20% of its body weight.
When first discovered the puggle was probably about 4 – 5 months old, and is now almost fully spined and getting ready to leave the nest. In fact a few days ago we watched as the young one appeared and ventured off on its first little jaunt. It’s a bit wobbly on its pins, but a capable digger and very attuned to sounds and smells, immediately becoming a partially buried prickly ball when feeling threatened.
It eventually made its way back to the burrow and during its mother’s next visit we were able to sneak up and record the repetitive rasping sound of the puggle suckling on its mother’s milk patch (click audio below) as they lay only partially-buried beside each other.
There is limited knowledge and conflicting reports on echidna weaning. One reference has the young not weaned until about 7 months old after which mother and offspring may continue to share shelter sites and forage together until the puggle is 9 – 12 months old. Another reference states the mother has no further contact with her offspring after weaning it at about 6 months in mid-January to the end of February.
If the latter is the case, we can only hope our puggle’s natural curiosity is sufficient to let it find food and survive out in the big wide world, without heading onto the road!
More photos below:
It pays to be lazy (and sneaky)
Arguably some of the most beautiful insects in Australia are the Cuckoo Wasps (pictured). Sometimes called Jewel Wasps the colours are due to the way their multi-layered and pitted exoskeletons interact with light – the same as for Stag Beetles. They are a frequent visitor to the Blue-banded B&B. I found to my surprise that they are not at all interested in the Blue-banded Bees nesting in the structure like many of the other wasp visitors, but rather the Mud Wasps building nests there.
Cuckoo Wasps are named because the process by which they rear their young uses the same principle employed by Cuckoos, laying eggs in the nest of another species. Cuckoo Wasps are parasitoid meaning they are parasitic but the end point is the death of the host. Furthermore they are klepto-parasitoid (from the Greek word kleptein meaning to steal). They steal both nests and the food provisions from other wasps.
Throughout summer wasps such as Potter Wasps and Mud-dauber Wasps are busily constructing mud nests of different shapes and sizes. Into these nests they place spiders, caterpillars, etc (depending on the species of wasps) that have been paralysed. The female wasp then lay eggs on the prey and seals the nest. When the eggs hatch they have a supply of fresh food to eat.
In steps the Cuckoo Wasp. The Cuckoo Wasp does not build a nest. It waits around the nest site of a Potter Wasp, for example and when the Potter Wasp leaves the nest to hunt for more food the Cuckoo Wasp lays its eggs in the Potter Wasp nest. The Cuckoo Wasp eggs generally hatch first. The larvae consume the stored food supply and then the Potter Wasp eggs.
The pictured wasp flew into the house and was trying to get out. Though temporarily detained, no wasps were hurt making this blog.
Aye, Aye, Skipper
Australian butterflies are divided into six families. Some of these families have members which are familiar to most people, for example the Common Brown is of the Nymph family, the Cabbage White is a White and any of the swallowtails are of course of the Swallowtail family. One of the lesser known families is Hesperiidae, commonly known as the Skippers. The appellation comes from the tendency for this group of butterflies to dart and skip low over the ground when in flight. Pictured is a member of the family, a Greenish Grass-dart (Ocybadistes walkeri).
Skippers are small butterflies usually brown and orange in colour. They can be distinguished from other butterflies by several key features. Like all butterflies they have clubs on the ends of their antennae but in the case of Skippers the club is hooked, like a crochet needle (see photo above).
Unlike most other butterflies that hold their wings vertical when at rest, the skipper when at rest holds its back pair of wings horizontal and its front pair of wings at an angle to the vertical (pictured below). As a kid its stance reminded me of an F-111 (although the purists among you will tell me that the aircraft has its front wings horizontal and its tail ‘wings’ at an angle).
Skippers are key pollinators of flowering plants, therefore are good to have in your veggie patch. Their sensitivity to toxins and pesticides makes them important environmental indicators.
Unlike the adage about cooks and broth, lots of skippers are good.
Focus On Fauna 