Esperance Fauna

Flower Spider - Diaea species 'Mallee'

2009-11-14T19:04:00.007+08:00

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Flower Spider - Diaea species 'Mallee'

Flower Spiders belong to the Thomisidae family along with 27 genera and nearly 150 Australian species, and this only represents the described ones, as many like the above await scientific classification. There are a number of white spiders in this group, but those in the genus Diaea can be recognised by the eye arrangement that is shaped like a smiley mouth.

These are ambush spiders that normally wait camouflaged on similar brightly colored flowers for a visiting flying insect in hope of a nectar meal, but end up being a meal themselves. Interestingly, the spiders above were not on a blooming flower - one was under a cluster of bright yellow pop-flowers, whilst the other was on a very odorous plant that had finished flowering, but clearly still attracting flying insects, as this spider was waiting exposed on top of a leaf and possibly hoping it looked like an actual flower, which may represent another hunting technique of these spiders.

I have denoted this species as 'Mallee" simply because that is where I found them, although each was on a sandy inclusion with a number of heathland species. The first was encountered at 45 km (28 miles) north of Esperance, whilst the other was 110 km (68 miles) NW of Esperance and were discovered during October/November. Maybe arachnid enthusiasts can just go looking and find these spiders, but I must rely on accidentally crossing their paths when looking at the vegetation, so for me to encounter two of them within a week or so, I suspect they might be common in these more arid inland locations.

Bag-shelter Moth - Ochrogaster lunifer

2009-10-30T19:13:00.005+08:00

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Bag-shelter Moth - Ochrogaster lunifer

On the mainland Ochrogaster lunifer is just about Australia wide and because of this wide distribution can be highly variable in color and markings. Amongst the moth studying entomologists there is the suspicion that there may be more than one species represented under the O. lunifer banner. The one photographed above is one of the more unusual and highly spectacular forms, with the photographs not doing the coloration justice due to a camera failure. It was a rich golden color not unlike my photos in another post of the Case Moth - Lomera pantosemna, also the abdomen was horizontally striped with bright orange and black bands, so quite a stunning individual.

The caterpillars are known as Processionary Caterpillars and move from one food source to another head to tail. However, I have not noticed this habit locally, although their silken nests that usually envelop small Myrtaceae shrubs close to the ground, are not infrequently encountered, and for this reason I do not think local Bag Moths produce as many larvae compared to the long lines of Procession Caterpillars noted elsewhere.

The male 2.5 cm (1") long moth above was seen over a couple of days during mid-October and unless they ignore house lights to unerringly follow the pheromones of the female moths, are not particularly common in the sandy heaths around Esperance. Although apparently, they are only around for a short period as they have no mouth parts to feed and so die within a few days after they have mated and started a new generation. As a word of warning, the hairs on the caterpillar, their silken nests and those on the tail end of the adults can cause skin rashes, so should be avoided, nevertheless they are well worth a prolonged gander.

Southcentral Pyrgomorph - Monistria consobrina

2009-10-08T17:25:00.004+08:00

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Southcentral Pyrgomorph - Monistria consobrina

A more recently described member of the Pyrgomorphidae family and differs from a similar local species, the Orange Grasshopper - Monistria maculicornis http://esperancewildlife.blogspot.com/2009/07/orange-grasshopper-monistria.html primarily by the size of the spots, which are smaller with M. consobrina.

The above couple were encountered during the day in shallow sand over limestone near Quagi Beach (55 km or 34 miles west of Esperance) where they were part of several individuals in an opening, who scattered at my approach. The smaller one who is riding on the back of the much larger female is a male, which is apparently not unusual in the Monistria genus, where the genders are markedly different in size. The male in this instance is not mating with the female, but has made his claim on her by taking up his jockey-like (and mating) position, thereby stopping other males from mounting her. In this position he will vigorously defend his seat against other males and may have lost one of his small wings in the process to reveal the bright red marking that normally covers it.

The red patch is a means of defence against predators, not other males, and if they are about to be attacked by a bird, retile or mammal will flutter these small wings to flash the bright red splashes to indicate to the potential predator that they are not very good to eat, or be dangerous in other ways. As these grasshoppers generally eat highly aromatic foliage and other plants that would make them very distasteful, therefore from the predators point of view, not worth eating.

The size of the female was 4-5 cm (2") in length and quite stocky, and going on the action of the male, they were likely gathering to mate, which in this instance was the end of September.

My thanks to Dr David Rentz and Martyn Robinson, the latter from the Australian Museum for identification and background information on the Monistria genus.

Dichromodes confluaria

2009-10-05T15:30:00.007+08:00

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Dichromodes confluaria - Geometridae

A distinctively marked delta winged moth that is common to the Esperance region. It belongs to the Geometridae family whose larvae are commonly known as Loopers or Inchworms based on their looping locomotion, when they bring their rear end to the head end, thereby creating a loop with their body. It also belongs to the Oenochrominae subfamily that are well represented in Western Australia with numerous family members relying on the flora family Myrtaceae for sustenance. Myrtaceae includes Eucalyptus, Melaleuca and a vast array of other genera, most of which are very common here, as are the invertebrates (like this moth) that depend upon them.

Dichromodes confluaria is attracted to house lights and can often be found clinging to windows on calm, humid and not too cold evenings, particularly during August and September. There are males and females in the photographs above, the males have the attractive comb-like (pectinate) antennae, whilst the females have simple whip-like ones. Size wise, the head/body length is between 1.5 and 2 cm or nearly 3/4", although recently I have come across several closer to 1 cm, which gives them a considerable size range. Such differences also apply to people and in some instances to the same extent, so we should be open to such events.

Apterogryllus species - Gryllidae

2009-09-06T18:35:00.002+08:00

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Apterogryllus species - Gryllidae

Gryllidae is the largest cricket family and the members are known as the 'true crickets' when compared to other Orthoptera families. The genus Apterogryllus is an endemic one and collectively known as Wingless Burrowing Crickets, as they make extensive burrows and spend much of their time there. Their vertical burrows are 30 cm (12") or more in depth, with an enlarged living and vegetative storage chamber often with one or more side tunnels. During the heat of summer the entrance is sealed off, leaving the cricket safely entombed to emerge after seasonal rainfall.

The Australian Faunal Directory lists 20 Apterogryllus species, of which most were described or revised during the 1980's. From the distribution of these species, it is clear they are primary a tropical group, being largely found in the Northern Territory and Queensland. In Western Australia there are only 4 described species and all were collected from the far north of the State.

As these crickets are wingless, it is thought with their limited means of migration and sedentary lifestyle, various groups could easily become isolated to evolve into numerous localised species. If this speculation is valid, then the southerly distribution of the Apterogryllus species above, may mean it is undescribed

The photographs of the above male burrowing cricket were taken in late March, a time when the first rains often begin to fall and although these are not sufficient to cause flooding in our local sandy soils, it could have stirred a cricket predator requiring the cricket to flee for its life, or as I suspect, he was seeking a female wingless borrowing cricket, as is common with many burrowing male spiders at this time of year, who take advantage of pleasantly warm and humid nocturnal conditions.

My thanks to Dr David Rentz for identification.

Leponosandrus lepismoides - Anostostomatidae

2009-09-04T16:54:00.005+08:00

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Leponosandrus lepismoides - Anostostomatidae

Anostostomatidae is another cricket family thought to be of Gondwana origin, with most genera restricted to the southern hemisphere. In New Zealand they are represented by several endemic weta cricket groups including the Giant Wetas that can reach 10 cm or 4" in head/body length, which are considerably larger than Australian family representatives. Of the Leponosandrus genus, L. lepismoides is the only species, but is widespread in Australia. However, I have not found it to be particularly common in the Esperance region, although this may be due to my limited nocturnal observations and it may be more common elsewhere in the district.

These crickets are also known as King Crickets and are represented by several Australian genera and include others where professional opinion differs, or where further research is required, so like others in the Orthoptera Order, there is much to keep entomologists occupied for years to come.

The diet of King Crickets is quite diverse and includes extensive hunting and scavenging of most animals within its size range, they will also consume many soft organisms, including herbs, fungi and fruits, so they are quite high on the invertebrate food chain, although they too fall prey to large spiders, night birds and small predatory mammals.

Leponosandrus lepismoides is around 3 cm in head/body length (little over 1") and I have only seen them in October, although they must be around at other times, but probably in a more productive location. This I would imagine to be around ephemeral swamps and flood plains, where their preferred food types would be more readily available.

My thanks to Dr David Rentz for the identification

Gryllacrididae species B - Raspy Cricket

2009-08-28T16:58:00.003+08:00

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Gryllacrididae species B - Raspy Cricket

This Raspy Cricket is much smaller than Gryllacrididae species A, the other common local species (http://esperancewildlife.blogspot.com/2009/08/gryllacrididae-species-raspy-cricket.html), being less than 2 cm (1/2") in length, but although smaller it has incredibly long antennae of around 6 times its head/body length. Why it should need them this long is to me a mystery. although I have watched them feeling into every crevice as they move slowly along when on the ground. Presumably if it encounters a lurking predator, it at least has a 6 body length start, which may explain why the antennae of some crickets are broken. However, the larger huntsmen spiders seem to catch a few.

Disregarding the size difference between this species and Gryllacrididae species A, there are other differences that a close look will reveal. The egg laying ovipositor of the females is the most obvious, being long and straight with species A, but shorter and curved with species B. Also the mating male of species A, grasps and grimly hangs onto the female's ovipositor, whereas species B hardly touches it. Maybe the additional weight of the larger species requires it to gain additional support.

This smaller cricket appears to be more secretive than the larger one and is usually only encountered during March/April when they are commonly seen and heard calling for mates, but rarely noticed at other times as is the larger Raspy Cricket.

Gryllacrididae species A - Raspy Cricket

2009-08-24T16:09:00.005+08:00

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Gryllacrididae species A - Raspy Cricket

The crickets in this worldwide family are not well known with the last major Australian review published in 1990 by Rentz and John. The Australian Faunal Directory lists 28 genera and almost 100 species, but estimates suggest the number of species is closer to 200 and worldwide 600, giving Australia about a third of the total family population. Gryllacrididae is primarily a southern hemisphere family with only a few species occurring north of the equator, thereby providing strong evidence for a Gondwana origin.

Many species dig vertical burrows and line them with a silken substance they produce from their mouths, others use this substance to make shelters by gluing leaves together. They are nocturnal and being omnivores, venture forth at night to hunt small invertebrates or to feed on vegetation or detritus. Interestingly, there is evidence that they use the stars to navigate the way back to their shelters.

From an ecological point of view, these crickets play an important role in the food chain and although they are predatory themselves, they are commonly preyed upon by larger animals, particularly mammals and the larger spiders. Another feature of the Gryllacrididae crickets is their very long antennae, often several times the length of the insect, which they fold back over themselves.

There are several common names for these crickets, but most of the Australian ones are generally known as Raspy Crickets, due to the raspy sound they produce when they rub their abdomen against their legs, which they can use as a means of defence. Most of these crickets are apparently very habitat specific, but if you have ever taken the trouble to look closely at them, superficially they all look very much the same. So with that factor in mind and without microscopic examination, we appear to have at least two or three common species (one or maybe two large, and one much smaller) in the sandy heath habitat where most of my observations of these insects have taken place.

The single species above, or possibly 2 similar sized species are the larger of the local Raspy Crickets, having a head/body length of around 3 cm (11/4") and are regularly encountered during December and January, and again during April and May, leaving them noticeably absent during winter and the height of summer when they presumably remain in their shelters.

My thanks to Dr David Rentz for identification.

Psacadonotus species - Tettigonioidea

2009-08-20T21:42:00.006+08:00

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Psacadonotus species - probably P. kenkulun

These katydids are not well known and currently Psacadonotus has only 8 species, of which some are represented from only a handful of individuals and one northern species by a single insect. They mainly inhabit the southern heathland of WA and SA although they are not found on the intervening Nullarbor. In the Esperance district there are three known species, Psacadonotus psithyros recorded west of Ravensthorpe, Psacadonotus serratimerus near Mt Ragged, and Psacadonotus kenkulun that is recorded just a few kilometres away from my sightings and is quite likely the same. The Psacadonotus katydids belong to an interesting group that are flightless and predatory on other invertebrates. The head/body length (excluding the ovipositor) of the illustrated species above was around 5 cm or 2 inches.

Interestingly, most collected Psacadonotus insects are male, whilst all the ones I have encountered were female and of which, two were laying eggs and had their ovipositors deep into the soil, a situation according to David Rentz that is rarely seen. I would imagine the local very deep, fine grained white sands are ideal for their egg-laying activities, I also slash walking tracks and periodically burn pockets of vegetation, both of which provide many small open areas these katydids need and apparently seek. Despite being flightless, these insects do have long legs that are used to walk rather than hop, but they can appear and disappear remarkably quickly, so no doubt could travel a hundred or so metres to reach ideal habitat, likewise the juveniles could disperse the same way, as I have not seen them either.

Being both a grazer and a predator, I would think their most productive food sites would be low-lying areas around receding ephemeral swamps (locally very widespread), where herbaceous vegetation and small invertebrates are more common. So would suspect they spend most of their time around the swamps and flood plains, with the pregnant females visiting the well-drained sandy hillocks to lay their eggs. This could possibly explain my unusual female observations.

The timing of their appearance in this elevated sandy habitat also coincided with rainfall or high humidity and was noted during August, then again at the end of February to the latter part of May. They were not seen in Winter or during the height of Summer.

My thanks to Dr David Rentz for identification.

Meadow Katydid - Conocephalus species

2009-08-17T19:17:00.003+08:00

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Meadow Katydid - Conocephalus species

These katydids were originally called Longhorned Grasshoppers although they are not even closely related and actually belong to different suborders. The most obvious differences between katydids and grasshoppers are the katydids have long antennae (half to several times their body length) and the females have a long egg-laying ovipositor; whereas grasshoppers have short antennae (less than 30 segments) and the females do not possess an ovipositor.

The above Meadow Katydid is probably an undescribed species or an unusual color morph of a known one, but the actual insect (dead) is required to be certain. As I try not to interfere with wildlife I refuse to collect and kill them for any reason, therefore I must live with a certain level of ignorance if identification cannot be gained from a photograph, which to me is not a bad exchange.

The above Conocephalus species was photographed in early April, which is almost the same time of year as my record of Upolu Meadow Katydid - Conocephalus upoluensis http://esperancewildlife.blogspot.com/2009/08/upolu-meadow-katydid-conocephalus.html, size was also similar to that species.

Upolu Meadow Katydid - Conocephalus upoluensis

2009-08-14T17:50:00.005+08:00

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Upolu Meadow Katydid - Conocephalus upoluensis

The Conocephalus genus is apparently still very much a work in progress with many species undescribed. The last time the Subfamily Conocephalinae was comprehensively reviewed, was in 1891 by Redtenbacker when collections were much smaller and many species unknown. Dr David Rentz has done a considerable amount of research into this group and even after describing a number of new species, admits there are many pieces of the taxonomical jigsaw yet to be fitted together. Conocephalus upoluensis was initially only thought to exist on Norfolk Island, but in his most recent book "Grasshopper Country" states this species is the most common of the Meadow Katydids and personally identified the one in the above photos as the same species, which were taken in WA near Esperance. Yet if you check the internet, there are many references (some from highly authoritative organisations) that still regard the Upolu Meadow Katydid in Australia as having a solely Norfolk Island distribution, which I suspect only reflects the current confusion over the identification surrounding this genus. Upolu is an Island of Samoa, which I presume was where this katydid was first encountered, or thought to originate.

There is currently around 30 Australian Conocephalus species that are also known as Longhorned Grasshoppers, although they are only distantly related to grasshoppers, so not a good common name and Meadow Katydids is far more applicable. However these katydids apparently consume grasses, sedges and broadleaf sedge like plants. Around Esperance besides the Stipa (Speargrass) species, there are few native grasses, but we do have many sedges and sedge-like plants from which they presumably feed, unless they have developed a taste for introduced grasses of which due to farming we are resplendent.

This Meadow Katydid is not very large with a head/body length of around 2 cm (1"), but with the much longer wings, an additional 50% or more can be added to it physical appearance. Whether I have just overlooked these katydids I cannot say, but I have not found them particularly common and as the male above was recorded in late March, it is possible with their large wings, they fly in on the strong easterly winds that prevail during summer.

My thanks to Dr David Rentz for identification.

Marauding Katydid - Metaballus species

2009-08-11T19:46:00.005+08:00

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Marauding Katydid - Metaballus species

The Metaballus genus currently comprises 10 species and is another group of katydids from the large Tettigoniidae family. Those shown above are likely to be the more common species of the Esperance region, namely Metaballus frontallis the Common Marauding Katydid, but a specimen is required to be sure (I thank Dr David Rentz for the genus identification).

I am not sure how members of this group acquired the name of Marauding Katydids, although besides feeding on vegetation like most katydids, they will expand their diet by killing and eating other insects, so may well plunder available resources. Another meaning for Marauding is Predatory that would fit this katydids habits very well. Interestingly, this group is also known for practising mate selection role-reversal, where in certain situations, the females will compete with each other for a male with better genes or a gift of the nutritious male spermatophylax (a glutinous product of the male's reproductive glands that the females eat and being better nourished can lay more and healthier eggs).

Mate selection is quite interesting with these katydids and much has been written about them. Apparently, when the male Metaballus calls, a female can tell whether he is well nourished and healthy by the length of the silence between calls. Sub-standard males have longer silences between calls than alpha males, who the females select in preference, this is obviously the female doing the choosing (unless there is an abundance of females). The Role-reversal happens when there is a shortage of nutrition, then the females will compete for the male's spermatophylaxes, the male will then decide which female he will gift it and then mate with. In this he will tend to choose the larger female as she will produce more eggs. The male is apparently quite particular in his choice of mate, as he has literally invested a considerable amount of himself to ensure his genes are perpetuated (something like 25% of his body weight gos into producing the spermatophylax).

Metaballus frontallis is a widespread species occurring in sandy heathland along the south coast of Western Australia. They are normally active during daylight hours and found in the warmer months from late spring to early autumn.

Tindale's Shieldback Katydid - Oligodectoides tindalei

2009-08-08T19:33:00.005+08:00

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Tindale's Shieldback Katydid - Oligodectoides tindalei

Oligodectoides tindalei is the only species in the Oligodectoides genus from the large Tettigonioidea family. It occurs across all southern States except Tasmania, which may be due to it being very cold sensitive. Tindale's Shieldback Katydid is one of the smallest katydids and can be very common in mallee and heath environments, particularly where the lower story vegetation is made up of grasses and dry-land short stemmed sedges.

Around Esperance it is one of the small grasshopper like insects that do giant leaps to get out of your way when walking along bush tracks. It is little more than 1 cm (1/2") in head/body length, but getting a close look is almost impossible without a capture net, for those long legs make them excellent jumpers and being small too, very difficult to locate again once they have taken off. The male above was obviously a little disorientated being discovered at night in late March when many of his fellows are beginning to die off due to cooler night-time temperatures.

My thanks to Dr David Rentz for identification.

Kawanaphila species - Zaprochilinae - Tettigoniidae

2009-07-29T16:19:00.005+08:00

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Kawanaphila species - Zaprochilinae - Tettigoniidae

The genus Kawanaphila currently has 11 species that were described by Dr David Rentz in 1993. and who has also kindly identified the above specimens. These katydids form the major portion of the Subfamily Zaprochilinae, which contains 3 other genera and a total of 17 species and all are characterised by having specialised elongated mouth parts to enable them to reach, collect and feed on nectar/pollen, which in the process may also pollinate the flower. A previously posted katydid species Windbalea viride (http://esperancewildlife.blogspot.com/2009/07/green-westwind-katydid-windbalea-viride.html) is another member of this group and although strongly winged, has a similar mouth structure. There are 2 known Kawanaphila species in the Esperance region, K. mirla and K. yarraga, but there could be more involving range extensions of the other species, or the presence of unknown species. From the photographs above there looks to be at least 2 species, but microscopic inspection is required and for that you need the katydid.

These katydids are quite common in the Esperance region and seem to favour Banksia blooms, interestingly, most of these insects are females, with only a single juvenile male recorded. As the males of these insects are apparently not territorial, I personally wonder about the evident shortage. Size wise (head and body), the orange ones tend to be a little larger at a little over 3 cm (1"), whereas the darker ones tend to be smaller.

Unlike most crickets and grasshoppers, these katydids are most active during winter/spring, particularly in July, but I have also recorded one feeding in October. These katydids are nocturnal, so use the coldest part of the day during the coldest months. The only reason that comes to mind for this unusual insect behaviour is there are considerably less predators around at these times. I would also imagine being perched on a large flower where you are highlighted, have your head down feeding for extended periods and owing to your nectar feeding lifestyle would probably taste rather nice. So based on that, going to such lengths to avoid predators seems quite reasonable.

Green Westwind Katydid - Windbalea viride

2009-07-27T18:43:00.004+08:00

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Green Westwind Katydid - Windbalea viride

A very distinctive katydid from the south coast of WA, but currently it is listed as Critically Endangered in the IUCN (International Union for Conservation of Nature) Red List of Threatened Species, a listing just below the 'extinction in the wild' category. In the Banksia speciosa heath to the east of Esperance it is still reasonably common, but even here in this locally widespread habitat, there are many areas that have been cleared, degraded or become disjointed, which for an insect relying heavily on this type of vegetation, its long-term viability is of concern.

As can be seen in the above photographs the Green Westwind Katydid was only encountered feeding on the flowers of Banksia speciosa, which may include not only the nectar, but also the pollen.

The wings are held stiffly at an angle from the body, making identification easy and it is thought this distinctive wing arrangement may aid the katydid's camouflage, for when at rest in a leafy environment the elevated wings appear as a green leaf or the base of a stem. However juveniles lack wings, therefore cannot camouflage themselves in the same manner, so presumably must hide the best they can.

The Australian Faunal Directory lists two katydid species in the Windbalea genus, but only Windbalea viride is found locally. Those photographed above were encountered from November to late February.

My thanks to Dr David Rentz for identification.

Slender Snout-nosed Katydid - Mygalopsis pauperculus

2009-07-21T18:12:00.008+08:00

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Slender Snout-nosed Katydid - Mygalopsis pauperculus

One of the most endearing katydids, looking like a cheeky hybrid between a weasel and a prawn, but like other katydids it belongs in the large and diverse Tettigoniidae family. Those character laden small beady eyes either side of that long pointed snout and the even longer whiskers (antennae), present an impish little face full of inquisitiveness, but it is not as it looks! The eyes, snout and antennae are at the top of the head, whilst the mouth parts are tucked tightly in, permitting it to feed freely whilst still looking for predators, and if one appears, it can use the snout like projection to deter an attack. Such a defence would obviously be largely bluff, but with a large slow moving animal like this katydid, any additional defence other than from a green or brown camouflage that may or may not work, must be a plus.

It is interesting to note that this katydid has a green and an orange/brown form, which is independent of gender. I asked Dr David Rentz (who kindy identified the species) the reason for these color forms and he thought it a likely safeguard where at least some animals would be camouflaged regardless of environmental conditions. My observations are too limited to be little more than guesswork, but with the animals I noted, the green females were seen during spring and early summer, whilst the brown females were noted during the dryer summer/autumn. Males of both green and brown were encountered in the middle period during January. So seasonal environmental conditions may also play a role.

Whilst browsing the web I came across the following regarding the coloration of another Mygalopsis species that may also be pertinent here.

>>The environmental control of colouration in a bushcricket, Mygalopsis marki Bailey (Orthoptera: Tettigoniidae)
A. J. LYMBERY
Department of Zoology, University of Western Australia, Nedlands 6009, Western Australia and Department of Agriculture, Baron-Hay Court, South Perth 6151, Western Australia
Abstract
The environmental factors proximately influencing variable colouration in the bushcricket, Mygalopsis marki, were studied in natural populations and under controlled laboratory conditions. Two major components of variable colouration were identified; a green/brown dimorphism in ground colour hue (dominant wave length) and continuous variation in the darkness of brown insects, representing a contrast between ground colour value (brightness) and the intensity of overlying black pattern. Ground colour hue differed between natural populations in different seasons and at different localities. The proportion of brown individuals was greater in populations developing over late summer than over spring at the same locality, and in populations from drier localities, as indicated by vegetation type, in the same season. Experimental studies showed that colour change occurred at moults, with green colouration promoted by increased water intake in developing nymphs. Ground colour value and pattern differed between natural populations at different localities, but not in different seasons. Ground colour value was less, and pattern was greater, in populations from localities with a dense cover of forbs and grasses. Experimental studies showed that ground colour value and pattern were influenced by the intensity of incident radiation received by developing nymphs, with decreased intensity promoting lower value and greater pattern.<<

The Slender Snout-nosed Katydid is one of five species listed in the Australian Faunal Directory, which collectively are known as Sluggish snout-nosed katydids. Mygalopsis pauperculus is restricted to the southern near coastal region of WA and has a head/body length of around 5 cm or 2".

Sand Grasshopper - Urnisa guttulosa

2009-07-17T17:54:00.004+08:00

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Sand Grasshopper - Urnisa guttulosa

I have no idea as to how common these grasshoppers are in the Esperance region, but the one above had almost certainly been blown off-course as this species is normally an inland species inhabiting red sandy soils, thus enabling it to use its dark mottled colors to blend into the environment, whereas here on the south coast white sands, it stands out like a beacon.

These grasshoppers in their normal red sand environment, bury themselves (using their long middle pair of legs) so only the top of the head with the large bulging eyes are visible. Here it can hide, keep reasonably cool and conserve moisture in their hotter and more central Australian habitat. They do not occur in plague proportions like locusts and represent no substantial threat to agriculture. The above Sand Grasshopper was noted at the end of January and probably caught a ride on the frequent northerly winds of this time of year.

My thanks to Dr David Rentz for identification.

Australian Aiolopus - Aiolopus thalassinus

2009-07-14T17:40:00.005+08:00

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Australian Aiolopus - Aiolopus thalassinus

Aiolopus thalassinus belongs to the large grasshopper family Acrididae, along with the similar looking Australian plague locust, Chortoicetes terminifera, whose distribution reaches to a little north of Esperance, but whom no doubt will fly down periodically although not in plague numbers. The Australian Aiolopus has in fact a much larger distribution than the Australian Plague Locust, so you may ask why is it not also called a locust? The reason is not the physical difference between a grasshopper and locust, but a behavioural one! Locust swarm in huge numbers to migrate and devastate any agricultural enterprise encountered, whereas grasshoppers and this includes Aiolopus thalassinus, do not collect together in swarms nor migrate, and although they can congregate in large numbers and cause some damage to crops, they are nowhere near as numerous or devastating as true locusts.

This non-swarming behaviour of Aiolopus thalassinus is consistent throughout the world, where in subspecies form it occurs in warm and predominantly grassland environments. However they sometimes do take on some locust characteristics, like a feeding frenzy when food is plentiful and high in nutrition. resulting in a population explosion to then possibly pose a threat to local crops. However in Australia this threat is small, as with their non migratory nature, predators (of which they have many, including birds, mammals, reptiles, other insects and spiders) assist considerably in keeping their numbers in check, particularly in higher rainfall agricultural districts where predator numbers are usually higher, therefore Aiolopus thalassinus is rarely overly troublesome.

Locally, this grasshopper becomes noticeable when the weather warms in late spring and will persist (increasing in numbers) until late autumn, with some surviving into winter. When walking around bush-tracks during this period, invariably grasshoppers will suddenly lift-off at your feet to fly a short distance to then re-settle and most of these will likely be the Australian Aiolopus. In flight they have mostly clear, non-colored wings and are not particularly large, varying from 2.5 to 4.5 cm (1" to 13/4") in length (males generally being smaller than females).

My thanks to Dr. David Rentz for identification.

Small Balloonwinged Katydid - Tympanophora diminuta

2009-07-10T17:32:00.004+08:00

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Small Balloonwinged Katydid - Tympanophora diminuta

According to the Australian Faunal Directory the Tympanophora genus currently has 14 species and is another member of the increasingly large Tettigonioidea family, which are commonly known as Katydids.

The Small Balloonwinged Katydid is visually one of the most appealing of the katydids, particularly the instar (undeveloped wings) with an expressive face, big widely spaced eyes and the 'Popeye' proportioned forearms, the latter not repeated in the adult form (my thanks to Martyn Robinson of the Australian Museum for identification).

Both the katydids above are male, the females are wingless and have a long straight ovipositor, and although they are normally accompanied by at least one male I did not notice any nearby, so maybe mine were unattached bachelors. Esperance is reasonably central to the Tympanophora diminuta's territory, having been recorded 40 km (25 miles) east of Ravesthorpe, to near Mt Ragged 140 km east of Esperance, a total distance of around 280 km (175 miles). The territory extends inland for only 50 or so km (30 miles), as the Small Balloonwinged Katydid seems to be largely dependant on heathland and further inland you begin to enter the Mallee zone.

This colorful katydid is around 2 cm (3/4") in length (excluding legs and antennae) and I have noted it in the Esperance district during October and November.

Slender Gumleaf Grasshopper - Goniaea vocans

2009-07-07T15:37:00.002+08:00

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Slender Gumleaf Grasshopper - Goniaea vocans

Goniaea is another genus from the large grasshopper Acrididae family. Although these Gumleaf Grasshoppers are a little different by eating dead gumleaves, and are therefore usually encountered on the ground under eucalypts. They forage during the day and hide at night under leaf-litter, which brings into question their orange/brown coloration that is not a good disguise amongst the dominant grey toning of fallen vegetation. However, I would think this coloration is not primarily for concealment, but to advertise, their distasteful nature due to a diet of eucalypt leaves.

The ones seen locally, have been in a low-lying, flood plain (cool and moist in an otherwise dry environment) that is not too overgrown. Here they have been observed from January to April, although infrequently.

My thanks to Dr David Rentz for identification.

Orange Grasshopper - Monistria maculicornis

2009-07-03T16:46:00.004+08:00

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Orange Grasshopper - Monistria maculicornis

The Monistria genus is part of the relatively small Pyrgomorphidae family of grasshoppers, which contains 13 genera and around 25 species. I have not seen many Orange Grasshoppers in the Esperance region, which may just be my lack of observation, or a general lack of aromatic plants that are apparently consumed by these grasshoppers (As a general observation, aromatic plants are very much more common further inland than near the coast). It is thought the consumption of these odorous plants would make them very distasteful to birds and other predators, and in this instance, the orange coloration serves as a warning of this condition.

As can be seen above, this specimen has only scattered orange spots, but I have seen photographs taken elsewhere of very orange colored insects, so color intensity other than genetic composition, may relate to available food, maturity, or a even a hotter/drier environment. The one above (a female) was around 5 cm (2") in length and quite stout. Interestingly, the 'nose in the air' pose is very misleading, as a feature of this family is a pointed head (the part being held in the air), but the mouth parts are pointing down and here are actually facing the sedge-like vegetation.

I have only seen Monistria maculicornis in the month of March. And my thanks to Dr David Rentz for identification.

Bark-mimicking Grasshopper - Coryphistes ruricola

2009-06-29T17:59:00.006+08:00

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Bark-mimicking Grasshopper - Coryphistes ruricola

Coryphistes ruricola (kindly identified by Dr David Rentz) is very widespread and occurs in all States except Tasmania. It is convincingly camouflaged on rough barked trees, or amongst dead twigs and even possibly on dry Banksia cones, but sticks out like a sore thumb everywhere else. Growing to around 5 cm (2") in head/body length, it is attractively marbled in grey/brown markings, with short flattish antennae that is a species distinguishing feature.

The Australian Faunal Directory lists two other Coryphistes species, which are also widespread, but not in the Esperance region, making this grasshopper locally quite distinct. The most obvious rough barked trees in this district where this grasshopper can use its camouflage, is the Flat-top Yate, Eucalyptus occidentalis, and mature Banksia speciosa plants. However, many Bark-mimicking Grasshopper instars (juveniles) must be able to hide during the day in other locations, as they are often far from these plants and unlike the adults, lack wings to fly back. This is important as the Bark-mimicking Grasshoppers feed on a variety of low shrubs of which their bark-mimicking camouflage is of little use, particularly when feeding on colored flowers or green leaves. This they partly overcome by foraging mainly at night when there are fewer predators, plus probably use micro-habitats of dead vegetation on which to hide, where their camouflage can be put to better effect.

This grasshopper is reasonably common in heathland around Esperance and I have encountered them during spring and autumn, but not during hot summer or cold winter periods.

Migratory Locust - Locusta migratoria

2009-06-27T19:20:00.005+08:00

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Migratory Locust - Locusta migratoria

The Migratory Locust occurs in the warmer, somewhat arid regions of the world and often in plague proportions. It has two phases with the plague one called the Gregarious Phase and in Australia this is restricted to the western outback area of Queensland. The other, the Solitary Phase or non-swarming phase, is more widespread and has even been recorded south of Perth, but according to Dr David Rentz (who kindly identified my photographs) they are not recorded for the Esperance region, however they are not uncommon here, plus I have records of them going back several years. Perhaps they have been misidentified as the Yellow-winged Locust - Gastrimargus musicus, which although smaller, are when at rest, very similar to the adult Solitary phase of the Migratory Locust, but when in flight their yellow wings are quite distinctive and so they are easily separated.

Locally Migratory Locusts can be found in numbers during the warmer months from January to April and although they can still be encountered during May, they have become very slow and are fast losing muscle control, making them easy prey for predators like Magpies. They can grow to over 7 cm (3") in head/body length, so are a good meal for many a predator and no doubt would help greatly in building fat reserves to carry them over the scarce insect winter months.

Color variation is a feature of all locusts and is largely dependant on their phase, temperature and nutrition. In their plague Gregarious Phase they are yellow to orange in coloration but are not found locally. The Solitary Phase adults come in various morphs from brown, to grey, to green, with the green morph probably having had greater access to higher nutrition levels in the nymphal stage and likely represents a higher coastal rainfall background.

Male and female locust are easily distinguished as the females have a couple of small projections at the end of their abdomen (much like male crickets), whereas the male locust has a smooth and rounded rear, due to a protective plate that conceals the reproductive organs. A male and female example has been notated above.

Pachysaga ocrocercus - Tettigonioidae

2009-06-23T19:08:00.009+08:00

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Pachysaga ocrocercus - Tettigonioidae

The Tettigonioidae family is the largest family of Australian crickets with over 900 species. Common names for this extensive group are Katydids, Bush Crickets and Longhorned Grasshoppers, the latter included due to their long antennae, a basic feature separating them from Grasshoppers that have short antennae with less than 30 segments. A larger distinction separating Grasshoppers from Crickets, is the Crickets including Tettigonioidae females have a sword-like appendage projecting from their abdomen called an ovipositor, which is used to reach deeply into nesting materials in order to lay and keep their eggs out of harms way. Female Grasshoppers do not possess an ovipositor, but lay more eggs to counter any predatory activity as a result of a more shallow nesting site.

Pachysaga ocrocercus (kindly identified by Dr David Rentz) is a large tubby Bush Cricket with a body length of around 3 cm (over 1"). It is commonly found on deep sandy soils and occasionally on granite outcrops, and may be encountered during the day although they are more active at night. Their longitudinal brown markings allow them to blend into leaf-litter, providing they don't fall upside down like one photographed above, to reveal an attractive white spotted purple tummy, which rather destroys the effect of their well camouflaged dorsal coloration.

Despite their typical cricket/grasshopper shape with long rear legs, they do not hop, but slowly walk away with great purpose, usually to the nearest clump of vegetation in order to hide. Females are seen more frequently than males, although the males have less need to expose themselves to lay eggs, so may be more common than they seem to be. Pachysaga ocrocercus is somewhat ungainly when climbing sedges and shrubs and are usually found either on the ground or within 30 cm (1') of it. Locally I have recorded them from August to December and again in March, they favor calm although not hot or cold conditions, but with reasonable humidity. Egg laying has been noted over most of this period.

Net-casting Spider - Deinopis unicolor

2009-06-19T16:32:00.006+08:00

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Net-casting Spider - Deinopis unicolor

If you think you have seen a giant Daddy Long-legs Spider, then you have probably encountered a Net-casting Spider from the family Deinopidae, which for good reason is also known as the Ogre-faced Spider. In the Esperance region, there is only the one species, but in Queensland and NSW there are several. They use their long legs to hold open a small sticky silken, but stretchy net and when a flying insect comes within range, it quickly thrusts itself forward letting go of the expanded net in order to capture it.

With the local species the male is only slightly smaller than the female, but is slimmer and has longer legs. The female body length is around 2 cm (3/4") with the male slightly less, but the legs of the male (front and back) are close to 10 cm or 4" in overall length. These long legs give the spider a strange (running into the wind) locomotion as it holds itself well off the ground when on the move, to virtually glide on tip-toe with legs trailing, but with the femurs (thigh parts) remaining more or less horizontal.

These spiders only hunt at night, so in order to catch flying insects by actively ensnaring them, the Net-casting Spider has excellent eye-sight with two very large forward facing eyes, they also have six other eyes, but these are much smaller. Preferred habitat are rocks or something providing a solid background, with light intersecting vegetation where in a sheltered position, it can (whilst hanging down) lie in wait for passing prey that are funnelled along the vertical wall.

Deinopis unicolor is not particularly common where I am, which may just reflect the shortage of suitable habitat, but when they have been encountered, it has been from March to June.