Friday, 19 September 2014

A Most Primitive Moth

Meet Sabatinca sterops, one of the world's most primitive moths. Fossils of related species in the family Micropterygidae have been found in amber in Lebanon that date back at least 120 million years.

But why is it considered "primitive". Well, it bears the following combination of characteristics: chewing mouthparts (most Lepidoptera have sucking mouthparts or no mouthparts at all as adults); raised hair-scales and the forewings and hind wings are similar in shape and venation. These are considered basal features in the Lepidoptera.

Nine Australian micropterigid species are known. Most occur in eastern rainforests including Tasmania. Several species are purplish or with dark bands and are of similar size. All are presently included in the genus Sabatinca but have been divided into two groups. One, "The Australian Group", includes the "golden species" of which S. sterops is a member.

We encountered large numbers of this moth recently on the lower slopes of Mt Lewis (ca. 700 m), Queensland. They were most active dusk and shortly thereafter. Mt Lewis is covered by rainforest and it is incredibly dry at this time of the year. Some saplings are wilting because of the lack of moisture. Larger trees are dropping leaves. the undergrowth of annuals is mostly dead. So it was surprising to see this small moth flying in large numbers in the undergrowth.

S. sterops measures only 2.5 mm from head to tip of wings. The adults are said to visit flowers where they feed on pollen. Little is known of the whereabouts of the larvae of many species. Some have been found in rotting logs. It is hard to imagine the tiny caterpillars surviving in the dry soil of the rainforest. They may be associated with liverworts or other primitive plants present on branches or rocks.

S. sterops is known from specimens taken from Cooktown to Mission Beach, Queensland. With the tens of specimens we found at our site on Mt Lewis, there must be millions of the moths spread over its geographic range.


Literature
Zborowski, P., Edwards, T. 2007. A Guide to the Australian Moths. CSIRO Publishing, 214 pp. Collingwood, Vic.

Tuesday, 2 September 2014

A Small Mystery Solved

By the way, Spring is springing and it is good to see some regulars back in the blog business (see Snail's blog noted to the left of this offering).

A trip out Dimbulah way seemed slightly less than successful the other night until a I took a closer look at three tiny black and white cockroaches that appeared at the light sheet.


It seems they are the second known representatives of what was described as Ectoneura hanitschi (Burmeister). The type was photographed and appears on p. 250 of the cockroach guide. It is a small species measuring only about 5 mm it was attracted to Blacklight on a cool and windy night.


This lovely photo by Buck Richardson does not portray the dry, dusty and rather miserable habitat of the foreground. The light sheets were positioned not far from this "idyllic" setting. Trees included several eucalypts, Acacia, Grevillea and several small shrubs. The understory was largely grass, Speargrass, Heteropogon contortus, and Kangaroo Grass, Themeda. There were termite mounds close by and these may harbour this cockroach. But with 3 specimens showing up at light, the cockroaches could spend the day under loose bark or in leaf litter or elsewhere, who knows?

A few words about "hanitschi". This species was described from Burnside, Northern Territory. This locality is hundreds of kilometres from the Dimbulah site. Burnside is probably in the vicinity of what is now Marrakai, NT. We are a bit unsure of the precise location at this point. The original specimen was collected by Edward Handschin many years ago and described by Princis in 1965 as a "replacement" name for a taxon described by Richard Hanitsch in 1934.

The Burnside habitat is probably ecologically similar to the site near Dimbulah. In fact, several katydids reflect a broad distribution across the Top End of Australia. They include Conocephalus upoluensis (Karny), Nicsara bifasciata (Redtenbacher) and Chlorobalius leucoviridis Tepper just to name a few. So it is not entirely surprising to find an insect from two such widely separated localities. It seems quite possible that this cockroach will be found at locales between the two places should someone care to look.

Based on the specimens found near Dimbulah, this cockroach is misplaced in the genus Ectoneura. It is more appropriately ascribed to the related genus Choristima based on the presence of a single apical spine on the fore femur and the minute punctures on the pronotum. Chortistimas are typically more robust than most Ectoneura cockroaches.

Seems like an unduly amount of verbiage for a few little cockroaches. But there is a story for all creatures large and small!

Literature
Rentz, D. 2014. A Guide to the Cockroaches of Australia. CSIRO Publishing 318 pp.


Friday, 22 August 2014

Coremata

Coremata, including Hair Pencils, is a phenomenon associated with Lepidoptera. They are signalling structures produced by males that are seeking females. They have been proven to transmit pheromones that act as aphrodisiacs and even tranquillisers to females. Further they may act as repellents to rival males.

I have documented this situation before in this blog. The hairs protruding from the abdomen of Syntorarcha iriastis Meyrick, the sound-producing moth, are the Hair Pencils.

Moth of the family Arctiidae seem to be the champions when it comes to the ultimate in bizarre development of Coremata and Hair Pencils. I have seen the phenomena only twice, once on a fieldtrip in the 60's with the late Don MacNeill in California and the other just a few days ago in th Daintree region of far north Queensland.

Here we see a relatively common tropical moth, Creatonotos gangis (Linnaeus). This male has the portion of his abdomen extruded displaying the Coremata and the Hair Pencils. The tubes, the Coremata, are inflated by blood pressure and the hairs transmit the pheromones. The moth was probably in the early stages of this "broadcast" since the last few hairs have not been separated.

I have seen many individuals of this moth at night but have never seen it with this display. I was very fortunate to have had my camera handy and not to have stumbled or moved the twig where the male was perched. Even the slightest disturbance would cause him to retract the Coremata.

Viewed from the side, structures are even more striking.

This moth was described by Linnaeus in 1763. What would he have thought if he had seen it in this juxtaposition?

Friday, 15 August 2014

Constant Cacophany

Ever since the end of May on nights when it is warm and wet, the rainforest pulses with what seems to be a continual din of cricket song.

The songster is a short-winged field cricket, Cephalogryllus species.


This is a pretty large cricket, measuring about 25 mm in length. They seem to be quite common but localised to some extent with small aggregations here and there.

They are subterranean.  Males sing from the burrow entrances after dark on nights when the humidity and temperature is to their liking. It seems that they are silent when the temperature drops to 14C. The short wings serve only to produce the song. They are too short for flight.
There are 14 described species all from the Australian tropics. This one is most likely C. tau Otte and Alexander, but the hind leg is quite different from that described for typical C. tau. So it may be undescrbed.

You can hear a recording of this species at:
https://www.flickr.com/photos/naturenoises/10466004004/in/set-72157636917906914

Although the loud sounds coming from these crickets reminds one of a continuous calling tree cricket (Oecanthinae), the individual calls are just long trills followed by a pause. But they are not co-ordinated so the result to the ear is a continuous trill. They are highly ventriloquial and individuals are very difficult to pinpoint. Once this is successful, it is often a bit embarrassing that the calling male was so close and yet apparently "invisible".

The crickets use their heads to move soil to the surface when they are excavating, hence the origin of the generic name. I have not properly dug the burrows to reveal their structure. This is a tedious task as the burrows meander through a labyrinth of roots and stones. The few that I have dug produce only males. Several had last instar male nymphs.
This is a last instar male. Note the short, undeveloped first pair of wings, the tegmina.

The biology of these neat insects is still poorly known. They re said to drag dead leaves into their burrows. I have never seen an individual abroad at night. Baiting with an oatmeal trail has resulted in only a few cockroaches and beetles but none of these crickets. One would assume that the reason for the males' calling is to attract females. This would seem to necessitate females moving about on the surface of the ground but as noted above, females have not been found. I have checked the oatmeal at several times during the night.
It was noted in Otte and Alexander's treatise on the crickets of Australia that the excavated soil around the entrance to the burrows was peppered with cricket droppings. These can be seen as the black spots above. This may not be happenstance. Could the droppings have some attractive properties that aid in the procurement of females? On the other hand, they may have some repellant function to ward off enemies. Of course, at this point, this is just conjecture and there may be nothing associated with the droppings.

Cephalogryllus crickets seem to be very common and widespread. Similar loud calls are heard each night in the rainforest across the street from the Cairns Botanical Gardens and in the forest near the Gondwanaland section


Literature
Otte, D. Alexander, R. D. 1983. The Australian Crickets (Orthoptera: Gryllidae). Academy of Natural Sciences of Philadelphia. Monograph 22Pp. 1-477.

Thursday, 3 July 2014

National Moth Weeks Approaches

Dear All:

Have had hard drive problems recently but things are getting back to "normal".  regret that I have lost all my blog mailing lists.

 Arctiidae: Scaphidriotis camptopleura
 Crambidae; Pyraustinae; Agrotera amethealis 
 Noctuidae; Catocalinae; Avatha discolor
Eupterotidae; Eupterotinae;  Cotana serratonota (female)
 Notodontidae; Thaumetopoeinae; Epicoma contristis
Cossidae; Zeuxerinae; Endoxyla mackeri 
 Cossidae; Zeuxerinae; Endoxyla mackeri 

 Crambidae; Acentropinae; Magarosticha sp
Hypertrophidae; Eupselia sp

Saturday, 31 May 2014

A Tale Of Two Katydids

To a biologist, this is an interesting story showing the value of morphological, cytological and behvioural characters in solving a taxonomic anomaly.
Alinjarria elongata Rentz, Su and Ueshima, male

In the second volume of my Monograph of the Tettigoniidae of Australia I described 15 species of the genus Hemisaga. This and several other genera were accorded a new subfamily, the Austrosaginae. This subfamily occurs in the southern portion of Australia. Hemisaga does as well but there was one species that was a distributional odd-ball.

examples of the genus Hemisaga:

 A male of Hemisaga lunodonta Rentz, a species from Fitzgerald River National Park, Western Australia
A male of Hemisaga pericalles Rentz, a species from the south coast of Western Australia near Albany.

There was a single record of a female of what appeared to be a Hemisaga from Mataranka, Northern Territory. This locality was thousands of kilometres form the nearest record of the genus. One might first think that the specimen was mislabeled. But this was not so, and especially not so because it was collected by my predecessor at CSIRO Entomology, Dr KHL Key. Ken was meticulous record keeper and had exhaustive fieldnotes. When they were checked, this odd katydid was recorded as collected in a grassy area near the motel.

I described it as Hemisaga elongata noting that is had a suite of characters that was not found in other Hemisaga species.

In 1999 a trip was made to Mataranka and the species was rediscovered. Males and females were found mostly in Sorghum grasses at night. And it was found in other areas such as in the Palmerston Developmental area not far from Darwin. Here it was found in the shrubby vegetation behind the mangroves. This katydid seems to specialise in feeding on other katydids. In both localities our observations indicated a preference for Caedicia species.
 A female of Hemisaga elongata. Note the very slender shape fo the katydid.
A male of Hemisaga elongata. Note the elongate male cerci (claspers), the inspiration for the  name.

The story continues.

Local collecting trips conducted after moving to the northern tropics in 2003 took me and Jadon Van Pelt to the mixed open woodland north of Mt Malloy. To my astonishment, we found what looked like Hemisaga elongata. After several trips to the area, we found a small number of individuals over a period of two years. This katydid was an adult in July and August-during the dry season. The herbaceous vegetation was dry and grasses were dead. Not many other katydids were around but several grasshopper species were still present.

The Queensland species was found to be quite distinct from H. elongata. In fact there was enough evidence to place both species in a new genus, Alinjarria. [Alinjarria is derived from an aboriginal word meaning  "north", an allusion to the distribution of both species.] The common name for the genus is "Imitators" based on the deception that it was a member of Hemisaga. The species was named Alinjarria jadoni Rentz, Su, Ueshima in honour of Jadon who found the first specimen.

But this put a species on each side of the continent in the northern tropics. No other member of the Austrosaginae occurs in the tropics. Further study was warranted.

All of the austrosaginae katydids reported in the monograph had eggs that had distinctive "caps". Eggs of both A. elongata and A. jadoni lacked caps. In addition, the karyotype of both species demonstrated Alinjarria was different from any known species of Hemisaga.
Male of Alinjarria jadoni.

Using the morphological, both structures and the egg morphology, it was obvious that Alinjarria was not and austrosagine but a member of the subfamily Listroscelidinae. This subfamily has a number of genera in the tropics and all are known to be predators. Austrosagines, on the other hand, feed on seeds and fruits. So biologically Alinjarria was also better placed in the Listroscelidinae.

This blog was prompted by the discovery of A. jadoni in mixed woodland near Mutchilba, Queensland.

Metzger Road near Mutchilba, Qld.                        Buck Richardson photo

This area is not dissimilar to the habitat where Jadon's Imitator was originally collected. It is regularly "prescribed burned" so there is a minimum of native shrubbery and most of the herbaceous vegetation and grasses are introduced species.

Female of  Alinjarria jadoni from Metzger Rd

The vegetation was "crackle-dry". Daily rains along the coast have not penetrated inland very far. The katydids were not what one would consider common. Two males were found on the 25 May. Another trip was made on 28 May and a slightly different locality was searched. The vegetation looked the same but the katydids were not found. We returned to the original spot and 2 females were located at sunset. This was a sufficient series to validate the species from an area slightly west of the type locality.

The challenge now is to trace the westward distribution of A. jadoni. With this katydid appearing to be quite rare, this may take some time.

Literature

Rentz, DCF. 1993. A monograph of the Tettigoniidae of Australia. Volume 2. The Phasmodinae, Zaprochilinae and Austrosaginae. With contributions by D. Colless and N. Ueshima. CSIRO Pp. 1-386.

Rentz, DCF., Su, Y.-N., Ueshima, N. 2007. Studies in Australian Tettigoniidae. A New genus of Listroscelidine katydids from northern Australia. (Orthoptera: Tettigoniidae; Listroscelidinae). Transactions of the American Entomological Society, 133: 279-296.


Friday, 30 May 2014

The Last Throes of Summer

Here in the tropics we approach the Dry Season with cooler temperatures, lower humidity, less rain and fewer insects- It's almost winter in the tropics.

Harbingers of the end of the wet season are some of the following orthopteroid insects.

Meet the Mundurra Fierce Predatory Katydid, Hexacentrus mundurra Rentz.
 Males hang upside down and stridulate from dusk from low perches in open areas of grassland and mixed vegetation. The incessant song continues until late in the evening when tmeratures drop. The sound is loud and travels for a great distance. It can easily be heard from a moving car.
 This species is a true predator and it seems to specialise in subduing other katydids.
Females look quite different from the males. The wings are just used for short flights or gliding, whereas, the males wings (tegmina) are modified for sound production. Males can also take short flights when necessary. However, the escape technique is to drop deep into the vegetation and remain still until the danger passes.
The Giant Rainforest Mantis (at least 60 mm in length), Hierodula majuscula (Tindale), Mantidae; Mantinae seems to show up at the lights for only a few weeks at the end of the season. I have never seen nymphs around in the garden so I assume it drops by on its nocturnal excursions. The spines on the forelegs can deliver a painful prick if this species is not handled carefully.
The most surpsising drop-in is the Migratory Locust, Locusta migratoria Linnaeus, Acrididae; Acridinae; Oedpiodini. This large locust is thought not to fly at night and but I have found it at light in Kuranda sporadically over the years but only during May. I have recorded it in May 2005, 2009, 2010 and 2014. On our last trip to the Daintree, it was very common and large numbers of individuals would take flight when disturbed during the day. However, after dark many were found sedentary in grass and none were attracted to our lights. This species is a grass feeder.

The only plague of recorded for this species in Australia was 1974-76 during favourable years. However, overseas this species is a major pest of rice, corn, sorghum and related plants.