Meet an Emesine

Emesines are members of the Assassin Bug family, Reduviidae. They are often very elongate and stick-like. They are characterised by having raptorial forelegs- like those of a mantis. This species shows up at the light sheet on rare occasions and picks off moths and other small insects. It is a rather small insect as you can judge by the weave of the sheet.

Cassowary Tragedy

All the joy of the appearance of the latest batch of young cassowaries has suddenly come a cropper with Mr Cassowary showing up without any of his offspring. It seems some tragedy must have struck. Perhaps, the current drought was too much for the young chicks and they starved or they have met an early end at the hands of a goanna or python. Whatever, the entire clutch is gone and they will have to start again. Both the male and female Cassowary seem quite wary when they stop by.

Dust

You have probably read about the dust storms of recent days in Australia. Yesterday (24 Sept.) the dust arrived in Cairns, not far from here. There was little wind on the ground, in fact, in Sydney and Canberra there was little wind. The wind that carried the material was high in the stratosphere. But where does it come from? Some of the sources are agricultural fields. Others originate in river valleys where fine-grained sediment particles are being picked up by the winds.

What Caused the Dust Storm?
During the winter in Australia low pressure storms are generated in the Indian and Southern Oceans, whipping up huge seas (great for blackfish!) and creating severe cold fronts which sweep across southern and eastern Australia A severe thunderstorm with 100 km per hour (60 mph) plus winds formed in South Australia on Monday and began whipping up dust from the drought-affected outback regions. As the vegetations dries out, the topsoil is loosened, and it easily blows away. As the dust travelled into the eastern seaboard of New South Wales, which is in drought, it grew in size and by Wednesday morning was affecting most of NSW, the fifth biggest state or territory and representing 10% of the continent, and had descended on Sydney like a thick red blanket. Estimates suggest that during the peak of the storm, the continent was losing 75,000 tonnes of dust per hour off the NSW coast north of Sydney.

This is not entirely unusual. These storms happen every few years and have been occurring over the millennia, removing topsoil from the continent. This coupled with natural and man-made erosion make Australia one of the most infertile regions of the world. In brief, there is virtually no topsoil left. We are down to bedrock. This is precisely why the continent cannot sustain continued human growth. Resources are such that the carrying capacity for Australia is probably around 12-15 million inhabitants. Once we get over that number, problems arise. There is not enough arable land to feed such a population. Water resources, even with more dams, are limited as droughts are commonplace and “natural” in this part of the world. Recent estimations of the population increasing to 39 million in 40 years is really a doomsday prediction. Yet, the politicians see it as positive with their single paradigm “growth” being the sole measure of human development. How wrong they will be.

View of Cairns yesterday at 4.00 pm from Ross Lookout on the Kuranda Range Road.

As above.

What is It?

I noticed a blob on a leaf surface and then looked a bit closer. It moved. On touch it raised the curly structures. Under the microscope it became obvious that is was an insect resembling an imperfection in the leaf or a bird dropping.

The curly structures are actually waxy filaments. They can raise or lower them depending on the situation. Both Murray Fletcher and Lois O'Brien think it's a ricaniid--a fulgoroid sucking bug. Murray suggests it may be Aprivesa exuta.

Disturbed, the filaments are raised and the creature sits motionless.
The filaments are raised and positioned forward when the creature is disturbed, otherwise the are held flat between the hind filaments.
Note the hind filaments, seemingly paired on each side.
Examination of the head region reveals it is a fulgoroid, probably Aprivesa exuta. See some related bugs, the Flatidae represented earlier on this blog.

Sleeping Eggfly

The Varied Eggfly, Hypolimnas bolina, resting for weeks on the same branch, night and day.

If you have been reading this blog you may recall that in 2007 I noted a butterfly posed in the same position on a shrub over a period of weeks. Well it’s happened again this year with the same species, the Varied Eggfly, Hypolimnas bolina. This time it was not far from the 2007 observation. The Eggfly was first noticed on 15 July 2009 and was photographed during the day a week or so later. On 25 August the Eggfly was still there. It’s interesting because cold weather does not seem to be governing this behaviour. We have had several nights at 16C and daytime temps over 20C. The caterpillar is quite spectacular. I’ll keep you posted on the Eggfly's activities.

Cassowary delights; Cassowary calendar 2009 #2

Cassowary delights

What a thrill to se Mr Cassowary show up for the first time of the season with 4 youngsters. They are a little larger than the young he first showed up with last year indicating they are a bit older. He seemed unperturbed by my presence and allowed photos and admiration. Then, a quick as they appeared, they vanished into the undergrowth. Now let's hope the dogs, pigs and cars show a little respect.


13 Aug. 2009

Orchid Foes

Orchid Foes

You would think that by moving to the tropics one would be able to grow almost any orchid. Wrong. Where we live in the rainforest, there is not enough light to successfully grow most species. What you need in tropics is a cleared area where you can erect a shade house and control the light and the moisture. We chose to live in the rainforest without making many changes. So we are subject to the depredations of a great many creatures. Orchids seem to attract a number of insects that are intent on feeding on them.

Here are a few that occur in the Kuranda region beetles, moths, butterflies and katydids are the most common culprits. A beautiful butterfly, the Orchid Flash, Hypocaena danis (Fabricius), a lycaenid, is a great destroyer of orchid flowers. This native species attacks most orchids, native and introduced. Females are attracted to developing flower spikes, probably by some odour that the plants themselves secrete at this time. The female Orchid Flash lays an egg or two on a developing flower or along the spike. It never seems to lay more eggs than the spike can successfully carry. If on a developing bud, the egg will hatch and the tiny caterpillar will bore into the bud and then begin to feed. As the bud develops, so does the caterpillar and it eventually eats its way out and proceeds down the stem to other buds. If in flower, it eats the flowers and often assumes the colour of the flower itself, thereby concealing itself from potential vertebrate predators.

The Orchid Flash, beautiful but deadly to your orchids.


Larva of the Orchid Flash. This caterpillar assumes the colour of the part of the plant on which it feeds. The ant is "tending" to the needs of the caterpillar and receives sugary secretions for its efforts. Not a good association as far as your plants are concerned. 
This caterpillar has been feeding on the green stem and leaves of the orchid.
The pupa of the Orchid Flash. Once you find this, it's generally too late for your flowers. The caterpillar has done its damage.
Eggs of the Orchid Flash. You can prevent the eggs from hatching by just scraping them carefully from the buds or using a light pyrethrum spray. Best to move the plant indoors or it will be attacked again.

Beetles

In the beetle department, several species lie in wait to attack your plants. They are all very destructive. the most obvious is the Dendrobium Beetle Stethopachys formosa Baly. Adults are brightly coloured. In New South Wales they are mostly black and orange. In Kuranda, we have both orange and yellow beetles. The adults feed on the flowers of Dendrobiums, their relatives and hybrids and other genera such as Cymbidium. The beetles are very active and fly when approached, soon to return to their destructive activities. The larvae are more insidious. They bore inside the stems where they hollow them out and eventually kill the stem. Any group of native Dendrobiums can be seen with yellow, dead and dying stems caused by the larval activities. The pupal cases of the larvae can be deceiving. The resemble chunks of Styrofoam, a substance used by orchid growers in their potting mixes. So they can go unnoticed and develop without interruption if you are not a careful observer.
Dendrobium beetles feeding on flowers and foliage of a Dendrobium. Other species of orchids are also attacked.

Larva of the Dendrobium Beetle.                               Graeme Cocks photo

Pupa and pupal case of the Dendrobium Beetle. Note the similarity to a bit of Styrofoam.                                                                                                          Graeme Cocks photo


Orchid weevils are very small and can easily go unnoticed. However, their damage can be very extensive and frustrating. One species, Orchidophilus aterrimus (Waterhouse) is the primary culprit. (see # 1 in the plate). This species is not native to Australia but was introduced and is often “shared” amongst orchid growers when plants are exchanged or sold. Prena (2008) states that it is native to Indonesia, Malaysia and the Philippines. Another species, O. insidiosus Prena, was described from “Australia” but from specimens taken in San Francisco from Sarcochiulus hartmannii plants sent from the Sydney Botanic Gardens. It may not be native to Australia according to Prena. Still another little weevil, Tadius sp, occurs in Queensland and is widely distributed in the Oriental region according to Zimmerman (1993: 138). Oberprieler (in litt.) states that this weevil (placed in its own family, the Erirhinidae) has been reared from Vanda orchids in the Northern Territory. He also stresses that the Australian National Insect Collection has very few specimens of any of these and he would be happy to receive them together with the names of the orchids on which they have been found.
Orchid weevil plate from Prena (2008). O. aterrimus is shown in the top across. O. insidiosus is the bottom one with the spots. 

Katydids

Last but not least is the biggest, and potentially the most destructive “pound for pound”, of the insect pests of orchids in the Queensland tropics are members of the katydid genus Austrosalomona. Species of this genus occur up and down the east coast from Cooktown to Bateman’s Bay, NSW. In Kuranda, it is an undescribed species of the genus that is at fault. It does not restrict itself to orchids but will feed, at night, on flowers, fruits, developing shoots of a wide variety of plants. Because it its size and abundance, it can have a devastating effect on a small collection of orchids.

A male Austrosalomona sp. feeding on the flowers of Heliconia sp. at night.

Cockroaches

Almost anyplace in Australia where orchids grow, cockroaches can be found in and around them. One species, the Orchid Cockroach, Shelfordina orchidae (Asahina) has been found in orchid collections in Canberra and its feeding activities recorded by Lepschi (1989). It is thought to have originally come from Panama! Its gut contents have contained fungi and pollen. The same species has been collected in the wild at Lake Barrine, Yungaburra and Curtin Fig., not far from Kuranda. However, cockroaches are often found in orchid collections but actual observations of them causing damage are few and far between. They may just find the potting mixture a convenient place to live and may just “graze” on the particulate material on the leaf surfaces after dark. More observations are needed.
The Orchid cockroach. Many cockroaches of the family Blattellidae have a similar appearance and it's best to have your specimens identified by an expert to be certain that your have the genuine Orchid Cockroach. The common German Cockroach looks somewhat similar to this one but it is vastly different.

Other hazards to orchid culture in the tropics are Red-legged Pademelons (a small rainforest wallaby) and Brush Turkeys.

Acknowledgements

I would like to thank Dr Michael Braby for comments on the biology of the Orchid Flash. His books on the Butterflies of Australia published by CSIRO are a must for anyone interested in identifying Aussie butterflies. Graeme Cocks is thanked for some most fortuitous photos of the Dendrobium beetle larva and pupa. Rolf Oberprieler provided all the information quoted above on the weevils that attack orchids.

Literature Cited

Braby, M. F. 2004. The Complete Field Guide to Butterflies of Australia. CSIRO Publishing. Collingwood, Vic. Pp. 1-338. 

Lepschi, B. J. 1989. preliminary note on the food of Imblattella orchidae Asahina (Blattodea: Blattellidae) Australian Entomological Magazine 16: 41-42.

Prena, J. 2008.  A synopsis of the orchid weevil genus Orchidophilus Buchanan (Curculionidae, Baridinae), with taxonomic rectifications and description of one new species. Zootaxa 1783: 18-30.

Zimmerman, E. C. 1993. Australian Weevils Volume III Nanophyidae, Rhynchophoridae, Erirhinidae, Curculionidae,: Amycterinae, Literature consulted. CSIRO, Melbourne, Pp. 1-854.