This week’s images again focus on Hymenoptera in the sample, with several interesting Tiphiidae and large numbers of smaller wasps (Pteromalidae, Chrysididae, etc.).
Among the chrysidoid wasps were one male and one female of the subfamily Elasminae (Eulophidae). The pale hind tibiae of the female clearly show the diamond pattern that Riek, 1967 offers as diagnostic for the genus Elasmus. The female seems to key out cleanly as Elasmus margiscutellum Girault, 1915, a species recorded from Canberra (Mount Majura). The male seems close to Riek’s description of the male of Elasmus aquila Girault, 1912, particularly in the enlarged posterior bristles on the scutellum, although that species has pale fore coxae. The male of Elasmus margiscutellum is not described in Riek.
One of the flies captured this week seems to have been parasitised by a nematode or other “worm” that has apparently hollowed out at least the interior of each compound eye. The fly had no wings remaining and the head was rotated through 180°. Finding information on parasites of insect eyes is very difficult since searches repeatedly return pages on insect parasites of human and animal eyes. Any information on clades that destroy the eyes of flies would be welcome. I assume that the parasite also controlled the fly’s behaviour to climb upward (and fall into the sampling bottle) despite being so badly compromised.
The trap continues to collect a wide diversity of insects in the new location. I’ve photographed a larger-than-usual selection, including several striking flies and wasps, and three different beetles from the family Mordellidae (tumbling flower beetles).
Many thanks to all those who have assisted with identifications on iNaturalist or in person.
On 3 December 1855, Edward Newman read a paper to the Entomological Society of London on Characters of a few Australian Lepidoptera, collected by Mr. Thomas R. Oxley, subsequently published (in 1856) in the society’s Transactions (New Series, 3(8): 281-300). Oxley’s specimens were collected in Victoria, Australia, “at Forest Creek, Barker’s Creek and Campbell’s Creek, all on the Mount Alexander Range, and at a distance of about eighty miles from Melbourne.”
This paper described one new plume moth on page 300:
[i.e. Lemon-tinged white, with a pale fuscous crescent on the fore wings, and with hind wings slightly ochreous grey. (Wingspan 0.65 ? inches ?)]
White with a very slight tinge of lemon colour; on the fore wings is an indistinct brown mark just at the base of the cleft ; the hind wings are pale ochreous grey.
A single specimen only was taken ; it a good deal resembles P. osteodactylus, but is readily distinguished by the paler colour of the posterior wings, and by the citron-yellow — not fuscous hue — of the antennae. A second species of Pterophorus also forms part of the collection, but is so injured that I cannot venture to characterize it.
The type for tinctidactylus is apparently lost. Subsequent authors have suggested various ways to interpret Newman’s description.
In 1994, Michael Schaffer and Ebbe S. Nielsen (in Nielsen E.S, Edwards E.D. & Rangsi T.V., Checklist of the Lepidoptera of Australia) offered a new combination, Hellinsia tinctidactylus (Newman, 1856). No explanation was offered, but this reflects Newman’s original statement that his species resembled Pterophorus osteodactylus, which is now treated as Hellinsia osteodactylus (Zeller, 1841).
In 2003, Cees Gielis (in World Catalogue of Insects Volume 4: Pterophoroidea &Alucitoidea (Lepidoptera)) tentatively (with two question marks) suggested that Newman’s species might be an alternative name for Platyptilia celidotus (Meyrick, 1884). If this proved true, Newman’s name predates Meyrick’s and would become the accepted name for the species. However, there seems no reason to suggest the identity between these species. Newman is clear that his insect is yellowish, whereas Platyptilia celidotus is a greyish to ivory-coloured insect. P. celidotus does have an streak at the base of the forewing cleft, but this is straight and angled.
There is however an Australian plume moth found in the region where Oxley collected his specimens and which fits Newman’s short description. His comparison was with Hellinsia osteodactylus, which indeed has a lemon-coloured tinge:
Imbophorus aptalis (Walker, 1864) (originally Aciptilus aptalis Walker, 1864) is a lemon-yellow coloured species with a variable crescent-shaped fuscous mark at the base of the cleft, yellow antennae, and paler hindwings than Hellinsia osteodactylus:
The resemblance seems clear. Again, Newman’s description actually predates Walker’s description of Aciptilia aptalis and the name would have precedence, if the type were still available for confirmation.
This was the first week running a Malaise trap at the new location selected for the remainder of the project. It was operated in parallel with the original Malaise trap (just 10 m further north). For the results from the original trap, see Araba Bioscan 20-27 November 2020 (Original location).
The new position is slightly higher up a slope and less screened by vegetation on the lower side. Differences in air movements and sight lines presumably contributed to such a massive discrepancy in insect volumes.
Termites swarmed on Saturday 21 and Sunday 21 November and were well represented in both traps. The new trap however caught much greater biomass and many more species, particularly Diptera and Hymenoptera. A selection of the more conspicuous or striking species are illustrated.
This was the final week operating a trap at the original location. A second Malaise trap was run in parallel this week around 10 m away and caught a much wider range of species – see the following post.
There was a swarming of termites on Saturday 21 and Sunday 22 November and the bulk of insects in this trap were from this event.
There has been a noticeable imbalance in the insects collected in the Araba Bioscan Malaise trap to date. The vast majority of larger insects have been moths, with rather few flies or wasps. This week, I chose to add a second trap (a SLAM trap which operates like a small Malaise trap with four access quadrants instead of two sides) positioned around 10 m away in slightly more exposed spot. This page provides an overview of the material caught in this trap. The balance was very different with many more beetles, including three Euomma lateralis Boheman, 1858 (Tenebrionidae: Alleculinae) and one Pterohelaeus striatopunctatus Boisduval 1835 (Tenebrionidae: Tenebrioninae), and cockroaches, including one Robshelfordia circumducta (Walker, 1869) and seven Johnrehnia concisa (Walker, 1871) (both Ectobiidae: Blatellinae), and a larger number of insects overall. This was despite this trap only being deployed for less than five complete days.
This has encouraged me to set up a second Malaise trap in the position used for the SLAM trap and to compare this in the coming week with the original trap. Assuming a greater diversity of insects also occurs in the new Malaise trap, I will decommission the first one and effectively restart the clock on the project.