Arquivos de periódicos de junho 2019

19 de junho de 2019

Wasp Observations in Northern Victoria

This article first appeared in the Victorian Entomologist for June 2019. See the Entomological Society of Victoria



Ichneumonid Lissopimpla excelsa at Miepoll.

At some locations there is tall grass in which numerous insects will roost, like wasps. They certainly sleep in other spots too but they are quite easy to spot against the pale grass. There were common species, like the Orchid Dupe or Dusky-winged Ichneumonid Lissopimpla excelsa. Males of this species are attracted to Cryptostylis that emit the same pheromones as the female wasps and pollination occurs by pseudocopulation. There are many other species in the Ichneumonidae family with males and females usually not appearing significantly different (apart from an often long ovipositor in some of these species) but on these trips only a few species were seen.

Many female insects have a long ovipositor at the end of their bodies which is used to lay their eggs into something (such as larvae or pupae in the case of wasps). Some wasps are capable of inflicting a painful sting in us humans – these are usually species that hunt living creatures that must be disabled quickly. It is worth remembering only female wasps can sting as this is with a modified ovipositor. What they catch is actually food for their larva as the adult wasps in most species feed on flowers, which is where they are most often observed during the day (but photographing them there while busy feeding is more challenging).



Pompilidae Ferreola handschini at Miepoll.

A well known wasp family are the Spider Wasps (Pompilidae). Some of these get quite large (ones that prey on huntsman spiders) and many sport some orange coloration as a warning to potential predators to indicate they can have a nasty sting (I know, I accidentally stood on one during these trips). A fairly commonly encountered species was Ferreola handschini, which is mostly black with unusual orange “shoulders” (so is at least relatively easy to identify).

Wasps in the family Crabronidae hunt other insects, including catching flies in flight, so they are often very swift and agile flyers, and are also similarly hasty when feeding at flowers. They can feature vivid yellow eyes and among the more well known are the Bembix sand wasps, a genus with about 90 species in Australia. These dig nesting chambers in sand, when it is often easiest to photograph them. The second sand wasp pictured was a lot smaller.



Crabronidae (Bembicinae subfamily) Bembix sp. left and unknown species right, both at Burramine within metres

Probably the family containing the most familiar wasps (including the invasive European Wasp) is Vespidae, which includes Potter Wasp (Eumeninae) and Paper Wasp (Polistinae) subfamilies (among others). Below is a photo of Delta bicinctum, a not uncommon potter wasp but I have never seen a pair together. These were photographed in the morning where they had roosted in the grass overnight but they were already starting to get fidgety with my big black camera pointing at them.




Vespidae: Eumeninae Delta bicinctum pair still at their overnight roost at Peechelba East

Smaller but with a similar waist (petiole) to Delta, the attractive black and yellow Deuterodiscoelius species is not one I’ve seen before and one that hasn’t been photographed much. It too was in the morning before it had warmed up sufficiently. Also pictured are two similar black potter wasps with differing amounts of orange at the end of the abdomen.




Vespidae: Eumeninae Deuterodiscoelius sp. at Eldorado



Two similar Vespidae in the Eumeninae subfamily at Burramine

Paper wasps (Polistinae) build honeycomb nests hanging from vegetation, rock overhangs and artificial structures. Polistes humilis is widespread and common in south-eastern Australia (including Melbourne) but inland I also found Polistes erythrinus, which is dark brown and significantly larger.




Vespidae: Polistinae Polistes erythrinus at Burramine

The family Sphecidae goes by several common names including Thread-waisted Wasps. This includes the Slender Mud-daubers of which two species are relatively abundant in Victoria. Sceliphron laetum is generally more yellow than Sceliphron formosum (especially the antennae) and they have different patterns on their back. See http://museum.wa.gov.au/research/collections/terrestrial-zoology/entomology-insect-collection/entomology-factsheets/sceliphron



Sphecidae Sceliphron laetum at Burramine (left) and Sceliphron formosum at Peechelba East (right)

Another family are Thynnid Wasps (Thynnidae) where the females are wingless as they spend most of their time burrowing underground looking for insect larvae to host their offspring. The sting of these is said to be quite painful. Probably the most well known is the so called Blue Ant Diamma bicolorbut there are many more species. Many males in this family are tricked into mating with orchids that emit the same pheromone as the female wasp. Members show significant sexual dimorphism, the female is usually significantly smaller than the male as for many he takes her to the flowers for feeding. One in this family that I thought I saw quite often was a black one with yellow mouth parts however when I started to collate some images for this article I realised there were at least two species. One has dark legs and black shaded wings while the other has red legs and reddish wings. Before I noticed this I usually just photographed the first one at a site and therefore may have missed the other species (so I now pay more attention). Thynnid Wasps used to be classified as a subfamily under Flower Wasps (Tiphiidae).



Thynnid Wasps with black legs (left) and red legs (right), both at Peechelba East



mating pairs of Thynnid Wasps showing typical sexual dimorphism, both at Burramine

Both sexes in at least most Flower Wasps are winged, as are those of the similar family Scoliidae. Particularly inland I have regularly encountered the 15mm long males (excluding antennae)of the Yellow Flower Wasp Radumeris tasmaniensis but less commonly the quite large female. Both of them appear amazingly hairy. Males are also tricked into mating by the deceptive Calochilus campestris beard-orchid.



Thynnidae Radumeris tasmaniensis male left and female right, both at Burramine

So many different wasps (Australia has thousands of species), although I only saw perhaps a few dozen so one wonders where all the others are hiding. But this number also makes them difficult to identify. I am only able to get to family with most of them and I don’t know if there is a specialist that can help more. A lot probably look very similar and may require concealed microscopic features.

For all the observations I records during these three trips have a look at the following iNaturalist project I created for them:
https://www.inaturalist.org/projects/rr-2019a

Publicado em 19 de junho de 2019, 02:44 AM por reiner reiner | 1 comentário | Deixar um comentário

18 de junho de 2019

Dragonfly Observations in Northern Victoria

This article first appeared in the Victorian Entomologist for April 2019. See the Entomological Society of Victoria

This summer I had the opportunity to make several trips inland and spent time exploring the lower Ovens River (north from Wangaratta) and the Murray River (mostly a little downstream from Yarrawonga). Part of the reason was to try and get photographs of some inland dragonfly species that I hadn’t seen very often. Time was spent during the day to observe insects sunning themselves or waiting at breeding sites and also spotlighting at night for roosting ones. Early in the morning is also a good time to observe insects still roosting (before it gets warm enough for them) but on many of the days it became quite hot so the insects were active earlier.

The first visit to the area this season was actually an aborted trip through the alps after my camera played up. I camped near Wangaratta and while spotlighting I saw a Nighthawk dragonfly Apocordulia macrops*. Despite searching previously at known sites (as well as this location) this is the first time I had seen the species. Mine are now probably the only “natural” photos of them as previous ones are museum specimens or individuals reared from larva collected during water sampling. With a new camera and suitable weather I decided to return a few days later and this time saw two males roosting on the first night.



Nighthawk dragonfly Apocordulia macrops males.

During this trip I also visited a site along Reedy Creek below Woolshed Falls, Beechworth, where a few years ago I had seen some less common dragonflies. I again saw a few species including my first ever female Unicorn Hunter Austrogomphus cornutus*.



Unicorn Hunter Austrogomphus cornutus female left, male right

Two other species of interest were Royal Tigertail Parasynthemis regina and Stout Vicetail Hemigomphus heteroclytus. The latter is difficult to distinguish from Southern Vicetail Hemigomphus gouldii, which is much more common in Victoria. The only way I can tell is by getting a good view of the male’s appendages and refer to the key.



Royal Tigertail Parasynthemis regina female left, male right



Stout Vicetail Hemigomphus heteroclytus male, with a close-up of the tail

After returning home and looking on the map I noticed the reserve extends almost all the way to Eldorado, with numerous potential access points and camp sites, so something to visit on the next trip. When I returned I saw some female Hemigomphus gouldii (but still haven’t got good photos of them) as well as numerous more Austrogomphus cornutus.

Along the Ovens River north of Wangaratta I encountered a few of the Inland Hunter Austrogomphus australis. At one site there were two and I didn't realise at the time that one was a female – I was amazed at how adept it was catching a couple of Pygmy Grasshoppers (Tetrigidae) from her perch as they jumped past. It was only until processing the photos that I noticed it was a female – males at breeding sites are generally not that interested in prey.



Inland Hunter Austrogomphus australis female left, male right

On the final day along the Murray River I also finally managed to get some good photos of a mature female Gold-fronted Riverdamsel Pseudagrion aureofrons*, a species not very common in Victoria south of this river.




Gold-fronted Riverdamsel Pseudagrion aureofrons male top, female bottom-left, mating pair bottom-right

I did see a Twinspot Hunter Austroepigomphus praeruptus at Miepoll again (where the first modern recordings in Victoria were made), and also at a new location at Wahring a short distance away, but only males and no good photos.

For all the observations I recorded during these trips have a look at the following iNaturalist project I created for them:
https://www.inaturalist.org/projects/rr-2019a

  • Some of the photos of Odonata taken on these trips will appear in my upcoming book to be published by the Society soon (currently in limbo with them).

Publicado em 18 de junho de 2019, 05:21 AM por reiner reiner | 1 comentário | Deixar um comentário