Sunday 27 September 2020

Entomopathogenic Fungi'ed Fluffy Flies

Spring in Canberra this year has had an abundance of wet weather and variably cool mornings. Conditions which are ideal for a pathogenic fungus which infects a range of insects, but is particularly noticeable to us humans when it affects flies. Entomophthora is also sometimes known as the puppeteer fungus and causes infected flies to have distended abdomens, with spread legs, and outstretched, often forward-pointing, wings.

Entomophthora comes from the Greek roots entomo (entomo), meaning insect, and   jqora (phthora), meaning deterioration/damage/destruction/decay – so a very apt construction. It belongs to a group (Phylum) of fungi called Zygomycota, and is very far removed from the various fungi, such as mushrooms, bracket fungi, and even yeast, that we are more familiar with.

The reason for the name puppeteer fungus is the concept that some of these fungi effectively hijack the insect’s brain, turning them into ‘zombies’ with behaviours that enhance the further success of the fungal infection.

Entomophthora fungus is not uncommon, provided the right conditions prevail, but infected flies, apart from being small, tend to cling to the undersides of leaves or are otherwise unobvious and not noticed by the vast majority of people. I found a dozen or so infected and very dead flies early one dewy morning in mid-September when I was inspecting our nectarine tree to see how much fruit set there might be this year. Later, I found more on a range of other plants, including azaleas and on the undersides of the leaves of the olive tree. These provided opportunities for what I think are some beautiful, if rather gruesome, photos.

Several links to further information are provided at the end of this post.

Saturday 18 July 2020

Winter Damselflies

There are a lot of comments around at the moment by people noticing that some birds seem to think winter is over already for this year! Various species from thornbills to ravens have been seen collecting nesting material, and several species of cuckoos have been heard calling, both here in Canberra and elsewhere, quite unseasonally, suggesting they think the birds whose nests they parasitise might also be active, or nearly so.

And it’s true that for mid-July we have had relatively few severe frosts or particularly low sub-zero temperatures. It seems the dragonflies and damselflies have also picked up on this.

It was a slower wind-down to the dragonfly season this year, in my view, with several species persisting for longer than I would expect them to. Wandering Ringtails (Austrolestes leda), and even a few Inland Ringtails (Austrolestes aridus) which seem to be rather itinerant here in Canberra but had a relatively good season this year, were being found well into May, and even June. Not only by me, but by number of people submitting their photographic records to Canberra Nature Map (CNM). Tau Emeralds (Hemicordulia tau) also seemed to persist, admittedly in relatively small numbers, longer than I am used to, with one reported as late as 14 June.

And yesterday (17 July), a record came in to CNM from Shorty, aka ‘rawshorty’, of a Wandering Ringtail on Mount Ainslie saddle. What’s more it was a teneral male, meaning it was only recently emerged from its watery larval home (presumably a small dam in the Mount Ainslie Nature Reserve) and was not yet fully coloured-up, and was munching into what looked like a small water beetle or some such.

A teneral Wandering Ringtail (male) photographed by Shorty on Mount Ainslie.

It is known that in some places (that have a distinct winter that precludes pretty much all dragonfly activity) Wandering Ringtails may ‘over-winter’, which is not a usual behaviour of damselflies. But I never expected this would occur in Canberra which really does get very cold! I had made some half-hearted efforts in previous years to see if I could find any overwintering individuals, but had never been successful. So, when Shorty’s image showed up I thought it time to have another look.

I rationalised to myself that the best bet would probably be a small, well vegetated swamp with a northerly aspect which would allow any sunshine to warm the shallow waters quickly. So I decided to check out a tiny seepage swamp on the northern flanks of Black Mountain, just off Belconnen Way, where I know Wandering Ringtails can be abundant when the summer conditions are favourable. I had recorded a late emergence event of this species there on 14 May (32 individuals including seven mating pairs) and assumed they would be the last for the 2019-20 season.

When I arrived, the sunshine was weakly obscured by a haze of high cloud, there was a slight breeze, and it was a balmy 12.5°C (it had got down to a relatively mild 0.2°C overnight). It all looked very quiet except for the four cockies and four Wood Ducks and I spent a good 15 minutes scrutinising the sedges for any perched damselflies. But then, just as I was about to leave and was doing one final scan with the binoculars – there it was. A male Wandering Ringtail. All by itself, not moving but being gently buffeted by the breeze and presumably trying to soak up as much warmth as was possible. I clicked away, even the 400 mm lens finding the distance difficult, but any attempt to get closer would mean approaching it from the other side of the swamp and directly into the low-angled sun. But I had my proof and felt quite chuffed. And it really hadn’t been that difficult.

An adult male Wandering Ringtail at a tiny swamp on the northern flanks of Black Mountain in mid-July

I went and checked out the nearby small dam, largely shaded by trees, and as expected found no activity there at all. Returning to the swamp, I went to take just a few more photos, but the damselfly had moved on. I eventually relocated it about 2 metres away, and in a clump of sedge right on the edge of the opposite bank. I worked my way around slowly and what I hoped was unobtrusively until close enough to crouch down and use the little Lumix camera on macro, getting near enough to largely overcome the poor lighting direction. When my closeness did eventually disturb it, it fluttered weakly just 20 cm away and re-perched. Poor thing, I thought, not even warm enough to be able to fly properly.

It wasn’t until I got home and downloaded the photos that I realised the macro shots were of an individual with a malformed wing-tip, and obviously different to the individual I first photographed with the long lens. So – at least two males were present on this tiny swamp in mid-July. There’s no way to know if they were survivors of the emergence I recorded two months previously in mid-May, or had emerged much more recently, like Shorty’s male on Mount Ainslie, but it is clear that, at least this year, this incredibly hardy little species (they are only about 35-40 mm long and incredibly slender) can survive a Canberra winter!

Canberra Nature Map is at: 

Monday 9 December 2019

Christmas beetle cocky feast

Early one morning last week, I was wandering up my street (bird watching) and noticed a group of Sulphur-crested Cockatoos on the road under a large eucalyptus tree. They were clearly feeding on something on the ground. Closer inspection revealed their interest was in Christmas beetles. There were ten cockatoos on the ground, a further three in the outer foliage of the tree and a couple more on prominent perches nearby (possibly sentinels?).

The birds on the ground were feasting on fallen beetles – some alive and still crawling, many barely alive, and many more quite dead. The birds in the tree were clambering about the outer foliage deliberately seeking out and ‘plucking’ the beetles feeding on the fresh young foliage. 

In both situations, the cockatoos manipulated the beetles, using both beak and feet, in the same way they would an equivalent-sized fruit, or acorn; the softer inner parts of the beetle being scooped out and eaten before the exoskeletal husk was unceremoniously dropped, adding to the carnage below. From the remnants, it appears the muscle tissue inside the thorax was possibly the main attraction.

The following morning, a slightly smaller group of cockies again arrived on the scene and began helping themselves to the dwindling supply of beetles. They seemed a little less engaged, or a little more distracted, and were soon dispersed when a small dog showed up. Some of the cockatoos moved off down the street to feed on the under-ripe fruit of a flowing plum tree for desert.

My interest and surprise in these events was twofold. 

Firstly, the sheer number of Christmas beetles was impressive, particularly in times when the incidence of these beetles seems to be reducing year by year. I estimated at least several hundred beetles on the ground, and many more were visible in the foliage. As far as I could discern, all were Anoplognathus chloropyrus, the Green-tailed Christmas Beetle, even though several different species of Christmas beetles occur in Canberra.

Secondly, animal material is a rare component of the diet of Sulphur-crested Cockatoos. HANZAB (Handbook of Australian, New Zealand and Antarctic Birds - the Australian ornithologist’s ‘bible’) and another authoritative book on Australian parrots mention a few instances of insect material being consumed, including the larvae of longhorn beetles from dead trees, and the larvae and/or eggs of Diptera (fly larvae), Hymenoptera (ant eggs) and Orthoptera (grasshopper larvae and eggs). Christmas beetles are not mentioned. Indeed there is no mention of adult forms of any kind of insect being eaten, let alone such large, crunchy, heavily sclerotized ones as Christmas beetles (not that this would be an issue for the cockies’ massive bills).

When available, Christmas beetles are readily eaten by a range of other birds in the area, including the Australian Ravens that breed each year in the tree in question, Pied Currawongs, Australian Magpies, Noisy Friarbirds, Dollarbirds and so on. But this appears to be the first instance, at least that I am aware of, of Sulphur-crested Cockatoos exploiting this food resource. It seems this might be quite an unusual occurrence, and quite possibly related to the severity of the ongoing drought.

I hope enough of the Chrissie beetles survived to procreate and produce the next generation...

Tuesday 5 February 2019

Twin-spot Hunters find Canberra

It was Saturday afternoon and 40 degrees outside. I was in the relative comfort of the study, the fan blowing a cooling breeze, when a report came through on the online Canberra Nature Map (CNM) of a Unicorn Hunter – a type of dragonfly that, in the ACT, frequents sand or shingle beds along some of the lower altitude rivers. As a moderator for dragonflies on the CNM platform I logged in and had a look at the photo. An initial cursory glance showed a tell-tale yellow double band at the 7th abdominal segment, then I looked at the antehumeral stripe to ensure it was ‘attached’ to the collar – it was; but something about the spots on the side of the final abdominal segments, and the pattern of the yellow patches on the side of the thorax, just didn’t seem quite right. Then I looked at the location of the sighting. It was all wrong. It was from open woodland, though not too far from a few small ‘farm’ dams. But nothing like the sandy-edged river locations preferred by Unicorn Hunters.

The photograph submitted to Canberra Nature Map, initially suggested to be a Unicorn Hunter.
So I took a closer look at the thoracic and abdominal patterns against the various other ‘hunters’ in the Theischinger & Hawking field guide, and it became very apparent that the photo was in fact of a thing called Austroepigomphus praeruptus or Austroepigomphus melaleucae, the Twin-spot Hunter.

This species pair has a bit of a confused history. The original A. praeruptus was described by Selys, in 1858, based on a single specimen from South Australia; but the specimen was lost and has never been relocated. Meanwhile, in 1909, Tillyard described a very similar species from Queensland and called it A. melaleucae. Although the vast majority of known records are from Queensland and northern NSW, it seems that the species has now been accepted as A. praeruptus and A. melaleucae has been relegated to junior synonym status.

There are close to a hundred records of the species in the Atlas of Living Australia (ALA), generally from inland south-eastern Queensland and inland north-eastern NSW, but with some more coastal records, including as far north as Cairns and as far south as Sydney. Interestingly, there is a 1976 record from Elanora Heights in the bushland of northern Sydney, less than a kilometre from where I grew up and where I was a teenager at the time! There is also a tight cluster of three records by Reiner Richter, from January/February 2016, from a small drying creek between Shepparton and Euroa in northern Victoria.

Distibution of the 92 Atlas of Living Australia records (Jan 2019).

In a personal email, Reiner indicated to me that a record, in iNaturalist, is of, finally, a recent record of the species from South Australia. This was of an individual in a very poor state from the Adelaide hills. 

So the finding of an individual of this species in the ACT is an important and, for me personally, very exciting outcome, and fills a sizable gap in the species’ distribution. I got onto John Bundock (the naturalist photographer ‘colleague’ of mine who found the dragonfly and submitted the record) immediately by phone, quizzing him on details such as was it just the one individual, how far was it from the nearest water, did it hang about, did he have any other photos of it etc, etc. It seemed to take a while, but I eventually convinced him of the significance and excitement of his find and we agreed to go out together in the morning to try to gather further evidence.

Next day, Sunday 27 January 2019, dawned quite overcast and we were even subjected to the occasional brief shower as we searched the first dam. Not the greatest dragonfly hunting weather. It remained cloudy for several hours but eventually gave way to more extended sunny periods and reached a temperature of 30 degrees. We searched the woodland where John had seen the dragonfly, now three days prior; we searched another couple of nearby small dams, all of which had relatively low water levels. Blue Skimmers and Common Bluetails were particularly evident, and we also recorded a few Red & Blue Damsels and a single Blue Ringtail, but we found no evidence of any Twin-spot Hunters.

We decided to head deeper into the woodland reserve to a couple of other small dams that I’d been wanting to survey for a while, and as we went, photographing any other insect life that caught our attention, my mind started to formulate a possible scenario. If this species is known to inhabit “sluggish streams and rivers, including isolated riverine pools”, it may well be likely that the species has adapted to a nomadic lifestyle. This might go some way to explaining its very patchy distribution through eastern and south-eastern Australia, and the individual John had seen may well have been an itinerant or wind-blown ‘traveller’. Fine as a theory, but not great for my personal aspirations of seeing the species which I desperately wanted to do.

At the other dams there were lots more of what we’d already seen and we added Tau Emeralds, an Inland Hunter and Wandering Percher. But still no twin-spots. So finally, defeated by lack of success and the heat, we decided to head back towards the car. We did a bit of a loop past another drying dam before rejoining the main track just above one of the dams we’d checked earlier that morning. As we approached, I noticed a Royal Tigertail perched on a small emergent branch just out from the bank. We hadn’t seen this species earlier, so I raised my camera and, even through the viewfinder, I realised fairly quickly that this was no Royal Tigertail. I mentally checked off abdominal banding and spots and thoracic markings and knew straight off this was in fact a Twin-spot Hunter. Yes! We spent about half an hour scanning the dam and taking hundreds of photos, eventually seeing three of the twin-spots together.

When we dropped down to the next dam, the one we first surveyed in dull showery conditions, we tallied no less than eight individual Twin-spot Hunters, all along one edge of the dam, perching mainly on logs and emergent submerged branches, but also occasionally on the stems of rushes or on the gravelly bank. What a difference a bit of sunshine can make.

This completely changed things. These were not blow-ins, but in all likelihood had emerged locally. The species was a ‘resident’, at least for one season, of the ACT.

Now we need to monitor over the remainder of this season, and more importantly, check other potential sites in the region, and see if they show up again next season.

Tuesday 8 December 2015

Inland Hunter inexpectata

Last Wednesday I took a lunchtime stroll along the northern edge of West Basin, a section of Lake Burley Griffin. It is just across Parkes Way from where I work and is in the heart of Canberra. I should confess that it wasn’t really just a stroll, so much as a survey of what odonates (dragonflies and damselflies) might have been present at the time. This is part of my fairly concerted effort this summer to get a feel for what odonate species occur in the ACT and when they are present through the season.

Apart from the expected damselflies - Blue Ringtails, Red & Blue Damsels and Common Bluetails (all of which have been present there for the past month or so) - I saw four or five individuals of a smallish black and yellow dragonfly. From the shape and body markings these were clearly a type of gomphid (Family Gomphidae) and at first I thought they might have been either Stout or Southern Vicetails (Hemigomphus heteroclytus and Hemigomphus gouldii respectively) which are not uncommon in some of the ACT’s rivers. But some decent views through the binoculars at close range of one individual made me think differently. It clearly had dorsal stripes down the abdominal segments and appeared to be some sort of ‘hunter’ rather than a ‘vicetail’, possibly a Unicorn Hunter Austrogomphus cornutus, but clearly not a Yellow-striped Hunter Austrogomphus guerini that I’m relatively familiar with. As I didn’t have my camera with me I took mental notes of what would hopefully be diagnostic ID features and jotted down a few comments in my little notebook.

Stout Vicetail Hemigomphus heteroclytus; Coppins Crossing, ACT; 5 Dec 2015.

Southern Vicetail Hemigomphus gouldii; Gudgenby River, ACT; 26 Dec 2014.

Unicorn Hunter Austrogomphus cornutus; Gudgenby River, ACT; 26 Dec 2014.

Yellow-striped Hunter Austrogomphus guerini; Gudgenby River, ACT; 26 Dec 2014.

When I got back to work I looked up the field guide (Theischinger & Hawking 2006) and the only thing that looked like what I had seen was Inland Hunter Austrogomphus australis. A species I'd never seen before.

The match was good for what I had seen, and nothing else really fitted. The problem was the field guide, and later the Atlas of Living Australia (ALA) when I looked it up, indicated that this species doesn’t occur in Canberra. The nearest records in ALA are from Wodonga (220 km to the south-west), Griffith (300 km to the west) and up near Tambar Springs (415 km to the north).

Distribution of Inland Hunter according to the Theischinger & Hawking field guide.

Distribution of records of Inland Hunter in the Atlas of Living Australia (ALA) at 4 Dec 2015.

It was kind of exciting but also frustrating that I had no visual record, and I determined to go back next day, with camera, and get some evidence/proof. So you can imagine my acute frustration when Thursday lunchtime revealed absolutely no sign of any of these dragonflies, despite walking back and forth and checking closely the locations where I had seen them the day before, under similar warm, bright sunny conditions.

What had been clear on the Wednesday was that these dragonflies were always associated with sandy/gravelly patches, be they gravelled pedestrian tracks along the edge of the lake or the tiny patch of gravelly sand that purports to be Acton Beach. I thought it unlikely that there would be several individuals at this location one day, and none the next, so I returned again on Friday lunchtime and this time was successful. I spent the better part of an hour photographing one of these dragonflies as it came and went, perching on the gravel and darting out over the water if I got too close or something else disturbed it. Just before heading back to work I saw a second individual and they had a brief skirmish the way dragonflies often do.

Inland Hunter Austrogomphus australis; Acton Beach, Canberra, ACT; 4 Dec 2015.

Inland Hunter Austrogomphus australis; Acton Beach, Canberra, ACT; 4 Dec 2015.

Inland Hunter Austrogomphus australis; Acton Beach, Canberra, ACT; 4 Dec 2015.

So I felt vindicated. Not only had I relocated at least two of these dragonflies, but I got quite a few photos, and most gratifyingly they clearly indicated that they were indeed Inland Hunters - and my mental note taking was validated.

Later that night as I went through the photos, culling the out-of-focus and leaving the small fraction that remained acceptable, it became clear, based on details of the colour development on the final four segments of the abdomen, and to a lesser extent the shape and completeness of the humeral stripe on the synthorax, that the photos represented at least six different individuals – all males. Only twice had the same individual returned for a second sitting. My initial assumption that the same individual had been coming and going was patently wrong.

But the question remains – what was this species doing in Canberra? The field guide indicates that the species “inhabits rivers and riverine pools, common and widespread in the inland river systems of eastern Australia.” Well that description is not at odds with the Canberra situation, but it doesn’t explain the near total lack of records of the species (at least in ALA) from the Murrumbidgee and Lachlan catchments.

So what was going on? Could it be that Canberra is within the species’ normal range but for whatever reason had not been reported from here before? Seems unlikely given that one of Australia’s foremost odonatologists, J.A.L. Watson had lived and worked in Canberra for many years. And why are there no records from along the lower courses of the ‘bidgee and Lachlan?

Or might it be that the species has expanded its range or increased its population size in this region? Could climate change be a factor? Or might the species be migratory and I had just happened across a cluster of migrants, or even wind-blown individuals from further west? Starting to scrape the barrel a bit here I think, particularly as, as far as I know, Gomphids tend to be rather territorial rather than migratory.

Anyway, I got to thinking if there were at least half a dozen of these things at one small beach right near the city, there must be others about. The closest place I could think of with similar habitat features was Grevillea Park at the eastern end of Lake Burley Griffin (LBG), about 3 km away. So early on Sunday afternoon I dropped by and scanned the ‘beach’ there and did indeed find and photograph another single male Inland Hunter.

Inland Hunter Austrogomphus australis; Grevillea Park, Canberra, ACT; 6 Dec 2015.

Inland Hunter Austrogomphus australis; Grevillea Park, Canberra, ACT; 6 Dec 2015.

But the more surprising discovery was of yet another individual at Coppins Crossing on my way home. Coppins Crossing is on the Molonglo River about 12 km downstream of the lake and presents quite a different habitat to the shores of LBG. The river there is fairly muddy (probably due to the massive multi-suburban development of ‘North Weston’ not far upstream) and not particularly fast-flowing except where it percolates through some rocky sections. The male I saw (which I had initially assumed was just another of quite a few Stout Vicetails present along that stretch of the river, and only discerned as an Inland Hunter later that night as I went through the photos) was perched on the top of a small rock in the middle of an expanded pondage where the water was murky and still.

Inland Hunter Austrogomphus australis; Coppins Crossing, ACT; 6 Dec 2015.

So it has been quite a special few days in which I’ve found a species that supposedly doesn’t occur in Canberra in three different Canberra locations. And I’m left wondering what to think about it and what to do about it. As a first step, I’ve written this blog post and will make the records available on ALA and Bowerbird…

And I'll keep hunting!