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 claris (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.

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

New Book

Every Australian knows Ms Densey Clyne from her many books and articles on the Australian biota and from her appearances on the "Burke's Backyard" TV show. Some may have thought she has "disappeared". Well she has. She moved from suburban Sydney to the wilds of Wauchope, NSW a few years ago where she continues her writing. 

Densey has just produced a new book, published by New Holland. She provides a note on its content below.

 

“An egg on its  way to being a butterfly.     The unlovely child of a

pretty moth.  Gardener's bane  and farmer's foe. Is that how we see

caterpillars ?   Are they  really  nothing more than expendable   pests,

guzzling grubs doing mayhem on our prize plants?      Nothing could be

farther from the truth.  Upstaged by their glamorous  parents,

caterpillars are worth more   than a passing glance or a shot of

insecticide. 

 

“ Caterpillars  play an important role in the health of the planet as

recyclers.     A major food source for other animals, their vulnerability

has led to amazing defence strategies and lifestyles.    They are the

architects and artisans of the insect world.   They carry inside them the

blueprints for some of nature's  loveliest creations,  and  they  too can be

stunningly beautiful.

 

“There are many books about butterflies and moths but their long and

eventful  lives as caterpillars is usually overlooked.  My book  “The Secret

Life of Caterpillars”  seeks  to set the record straight.     Aimed at

readers young and old  it presents the larval forms of the Lepidoptera   as

diverse and  fascinating little animals in their own right.   Densey Clyne"

Insects on the move

Two Migratory Locusts attracted to the lights in the rainforest at night.

Insects on the Move

 Having the light sheet operating each night presents some phenomena from time to time. Late last week a single Migratory Locust, Locusta migratoria (Linnaeus) landed on the sheet. This large grasshopper is not an inhabitant of the rainforest and it is not the first time I have found them here. On the 15^th of May 2005 one was found at the light and last week on the 15^th of May 2009 another (a female) was also found. Last night 2 males and a female were collected. The females were in reproductive diapause. During the day I have seen a few more of the locusts flying in the open.

 The Migratory Locust feeds on grasses and related crops such as sugar cane. These are the locusts that swarm in huge numbers in Africa. Their nocturnal movements have beenwell  documented. The presence of this grasshopper in the northern rainforests does not agree with the distribution maps of the Australian Plague Locust Commission  In our book A Guide to Australian Grasshoppers and Locusts, we show a considerably greater distribution of this locust in Australia than noted above. These locusts fortunately, do not cause the damage that they do in Africa and Asia in Australia.

 

A few water beetles on the ground below the light.


A single beetle taking refuge in the litter below the light. Perhaps, the beetle will fly off the following night.

Of related interest is the flight of the large dytiscid water beetle Cybister tripunctatus (Olivier) on the same night. Each year for one or two nights, large numbers of these beetles can be found at the lights of filling stations or at porch lights. I began collecting a few each year and placing them in my aquarium. They live quite peacefully with adult Australian Rainbowfish Melanotaenia splendida  and Purple-spotted Gudgeons Mogurnda mogurnda and, although they are large and considered quite predaceous, they don’t make moves on the fish at all. Perhaps, these species, which occur in the waterways in this area, have some chemical way of coping with the voracious appetites of the beetle. I can report that when cleaning the tank, the beetles readily bite my arm. They are often quicker than the gudgeons (what isn’t!) when a piece of meat is offered to the fish. The beetles are quick and swim off with it. The fish never attempt to capture the beetles. Indeed, the beetles are a bit too large for the fish to cope with and they do have repugnant secretions that are meant inhibit with such attacks.

 

The beetles that I capture at the lights live for at least a year in the aquarium and never attempt to leave. I guess they take one flight in their life and if they reach water, that’s where they stay. They readily eat flake fish food and will consume a dead fish. I don’t know the sex the beetles and have never observed any mating or egg-laying. Although the larvae of dytiscid water beetles are often called Water Tigers because of their predatory habit on fishes and other aquatic life, I suspect any young water beetle larvae would be consumed by my fish.

 

Now what is causing this movement of insects in the night? The moon is in the last quarter and the nights are clear and cloudless. I noticed that there were gyrinid whirligig water beetles also at the lights last night. As readers of this blog will note, we have a creek on the premises and the much larger Barron River is less than 1 km distant. I have puddled around in our creek after dark on a number of occasions and have not seen the dytiscids there. So the beetles may come from the Barron. I have seen them at lights in downtown Cairns indicating that they may fly considerable distances for whatever reasons.

 

There is a lot still to learn about the biology of some of our most common insects.

 

Prairie Dogs: A new book

A friend from childhood days in San Francisco, Con Slobodchikoff,  has published a book that deserves some publicity. Prairie Dogs are an icon of the Midwest prairie ecosystem of North America, but as one might suspect, their numbers have been critically reduced in recent decades due to all the usual causes.

 

Con and his associates have documented many aspects of the biology of these communal rodents in an impressive book. Of interest to me as a specialist entomologist dealing with creatures that communicate by sound, is the interpretation of the sounds produced by Prairie Dogs. Just last year I had the privilege of seeing a population of prairie dogs that are being re-established on the plains of Wind River Ranch, Watrous, New Mexico. They are appealing animals with a highly developed sense of community and this book will introduce you to their world.

The book can be viewed and ordered from Con's website.

 

 

Cassowary Calendar 2009 #1

It is with great relief that we report the return of the Cassowaries to our property. We have not seen them since last August. Up till then, they were wandering through each day, sometimes more than once. We had all sorts of negative thoughts as to what might have happened to them. The worst case scenario was that they had been hit by a car or that the loose dogs in the neighborhood had chased them away. The latter seems quite probable as these birds are susceptible to attacks from dogs. They can handle themselves if confronted by a single dog but if more than one is threatening them, they are usually goners. Neighbours across the street pay no heed to the leash laws and their dogs are frequently on our property. Other residents have seen them chasing the Cassowaries. We hope to be able to report on their presence regularly now.

Seeing the pair together might suggest that the courting season is upon us. If this is the case, the male will disappear for about 6 weeks while he incubates the eggs and then he will emerge with the season's hatchlings. Let's hope........

Tiger Moths (Family Arctiidae)

Tiger Moths!
Most North American readers will have a mental image of what a Tiger Moth (Family Arctiidae) should look like. A couple of examples are included below. We have equally spectacular species in Australia but there are not many of the true Tiger Moths (Arctiinae) that fall into that subfamily. However, we have many moths in another subfamily, the Lithosiinae. The moths in this group are appropriately called the Lichen Moths. In the Kuranda rainforests we have plenty of moss and lichens and more than 20 species of lithosiine moths come to our lights. Some are quite small and do not fit the image of a Tiger Moth by a non-specialist like myself. I get several species each night at the “light sheet”. My light sheet always evokes humour when the real moth-collecting professionals visit. It’s been hanging in the same place for over 5 years and has not been washed. The usual collecting sheet is white! This one is green because there is an accumulation of lichens and algae actually growing on the sheet itself (which is actually an old curtain). Lichen Moth caterpillars often “graze” on the fields of algae on the sheet during the day.

Most Tiger Moths exude distasteful liquids when mishandled. The ultimate in this defense is seen when froth bubbles up from the thorax.


The Light Sheet!


There are several Australian sites that cater to the Lichen Moths. There is even an article documenting the use of Lichen Moths as indicators of air pollution

I have been aided by the excellent website for the identification of Australian caterpillars. Have a look.

A few typical Tiger Moths in the Subfamily Arctiinae.


Halisidota tessellaris (Smith), the Banded Tussock Moth is a North American species. Photographed in Medford, New Jersey


A typical Australian Tiger Moth, Spilosoma curvata (Donovan), the Crimson Tiger Moth. Photographed at Bawley Point, NSW

Creatonotos gangis (Linnaeus) a rainforest Tiger Moth. The describer of this species was the Swede Carolus Linnaeus as you can tell from the name following the Latin name. It's inclusion in brackets () tells the user that Linnaeus originally described this species in some other genus. Being a Linnaeus name, it was probably described around 1758 and would be among the earliest of officially-named Australian species.

Amerila nigropunctata (Bethune-Baker) is one of several species of large Tiger Moths that appear at the lights. This one has large clear windows on the fore wings.

Amerila alberti (Rothschild) is a sluggish species that seems quite delicate. It's behaviour belies its poisonous nature. It, and other species in the genus, and other Tiger Moths for that matter, exudes a distasteful and probably toxic substance from the thorax whe it is disturbed.

Bubbles of froth from an irritated A. alberti.

Nyctemera baulus (Boisduval) is common visitor throughout the year. It is also known from New Guinea and some of the Pacific Islands.


Argina repleta (Drury) is known at the Crotalaria Pod-borer. The caterpillars of this moth feed on Crotalaria pods. The moth can be common at times. It is also known from New Guinea.

We have covered some of the typical Arctiine moths. Now here are a few Lithosiines.


Cyana sp. is brightly coloured. There is a reason for this. This moth, and others of the Tiger Moth family, is toxic to vertebrate predators such as lizards and birds. The bright orange colour is recognised by these potential predators and they avoid eating them. Arctiid moths often stay on the light sheet all day without being annoyed by birds and lizards. And well they should be. Members of the Arctiidae are loaded with alkaloids that are very toxic indeed. Cyana is a member of a mimicry ring involving Meullerian associations. Check out the link for a full discussion and a great photo of Fritz Meuller!


Heterallactis stenochrysa Turner is very common at our lights. It is a small species being only about 5 mm in length.


Microstola ammoscia Turner is a drab little moth that is present on the light sheet nearly every night of the year. It is a small species measuring about 8 mm in total length.



Scaphridriotis sp. is an uncommon little moth measuring about 5 mm in length. It usually perches with the wings slightly apart. Two species have been described in the genus.

Schistophleps albida (Walker)

The similar-sized Chamaita barnardi (Lucas)

Schistophleps albida (Walker) is one of two species that show up in autumn-the end of the wet season. This April often 50 individuals can be found on the light sheet each night. These are small, delicate moths and seem to lack scales. The moths measure about 6 mm in length. You can view the peculiar larva of this species. It occurs with C. barnardi. Check the antennae for differences.


Schistophleps obducta (Lucas) is a slightly larger and much less common species.


Macaduma sp. is slightly larger than the above and is rather variable in colour. It has a recognizable posture.


Teulisna bipunctata (Walker) is a much larger moth than some of those above. It measures approximately 15 mm and is easily ideitified by the pair of spots and the curvature of its wings. There are a number of drab grey species that resemble this moth in many ways. Most are yet to be named.

Lyclene pyraula (Meyrick) is one of the most brilliant of the Tiger Moths to visit our lights. It is always quiescent and never bothered by brids or lizards. It pays to advertise!


Asura polyspila Turner is well known to moth collectors in the tropics. It is a common visitor to lights. There are a number of species in the genus that differ in colour pattern.


Manulea sp. is a larger moth than many of the other lithosiines. It averages about 22 mm in length. Its resting posture is distinctive.

Manulea dorsalis (Walker). Believe it or not, this may be the same species as the one above. Perhaps, an example of extreme variation.

This caterpillar is grazing on the algae growing on the light sheet. Judging from the photos, it is likely to be the caterpillar of the moth above.

Oeonistis altica (Linnaeus) is a spectacular Lichen Moth. It usually rests high on its legs. It is beautiful when spread. This large moth measures some 25-30 mm in length. As far as I can tell, nothing is known of its biology.

Thanks to Ted Edwards and Don Herbison-Evans and Dave Britton for identifications and comments.

The Flatidae

Flatidae

Every so often the taxonomists get it right. The Flatidae is aptly named because they are, or most of them are. These small mostly greenish bugs are related to leafhoppers. They are members of the superfamily Fulgoroidea. This is a diverse group—really; more than 10,000 species are known worldwide.

Flatids visit the lights regularly and as with most of these sorts of insects, they are rarely seen during the day unless you happen to be looking in the right place. They are plant feeders, sucking the juices of certain trees and shrubs. The Australian species can be identified by using the very “user-friendly” key provided by Murray Fletcher. In fact, this is the reason for this blog. The key can be used to identify the families, and many species, of the Australian Fulgoriodea. We need more keys like this one. Up close, they are delightful insects and well worth a bit of time taken to identify them.


Paradaksha meeki Distant is known from northern Australia and New Guinea and is one of the larger species, measuring about 14 mm from head to tail. A beaut species only rarely seen at the lights.

Euphanta munda (Walker) is one of 5 species known from Australia. The genus is a northern one with species known from Nerw Guinea, Fiji and Indonesia. This one measures about 7 mm.




Siphanta is the largest known flatid genus in Australia with some 40 or more species known. So it's not surprising to find several in the Kuranda region. Determining their host plants would be the next step in attempting to understand their biology. Siphanta species are also found in the Philippines and eastwards to Hawaii. It appears that some species have been introduced through commerce to California. Siphanta galeata Kirkaldy is one of the larger species in the genus, measuring about 9 mm. It is known only from northern Queensland. The brown spots seem to be distinctive.

The Green Planthopper, Siphanta acuta (Walker) is a widespread species known from all over Australia as well as California, Hawaii and South Africa.

Geraldtonia protea Distant is the largest flatid we have around Kuranda. It is a giant measuring some 18 mm. Males have the dark spot that helps to camouflage it a bit, giving the impression of an imperfect leaf. Females are usually uniformly green. I see only 2-3 a year on the light sheet.

Not all flatids are flat in the sense of being laterally compressed. There are some that are dorso-ventrally flattened.

Uxantis comprises 15 species from northern Australia to the Philippines. Two species occur in Australia. This is probably U. consputa Stal. It is rather common but seasonal with most specimens coming at the end of the wet season, that is, late March.


Masilla sp. must spend the day resting on trunks or branches where they would blend in with the lichens and algae. Four species are known and this is probably the commonest, M. sicca Walker.