Toad Bug - Nerthra species

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Toad Bug - Nerthra sp.

Toad Bugs are small (between 0.5 - 1 cm or around 1/4" in length) and mostly live near aquatic habitats, but some can live in much drier environments. They belong to the worldwide Gelastocoridae family, which has over 100 species in three genera, but in Australia there is one subfamily (Nerthrinae) with only one genus (Nerthra) containing 21 species. I do not know if I have photographed (above) one of more species (I suspect two), but the five in the SW of WA are Nerthra adspersa, N. femoralis, N. hirsuta, N. stali and N. tuberculata, should anyone be interested in following them up.

Despite their small size these bugs are ferocious predators, by ambushing, running down, then pouncing on their invertebrate prey. They grasp their captives in their modified claw-like front legs and then immediately begin to siphon their soft inner tissues. I have seen them hunting ants in this manner (photo center right above), where the bug has been surprisingly fast and agile, with capture happening only a second or two from when the ant was first spotted.

The Australian Toad Bugs are very common, particularly around swampy habitats with a sand or peaty topping, permitting sub-surface moisture to spread out over the surrounding area. Here the majority of bugs hunt, but remain largely motionless or move slowly unless something of interest passes by. Their dull coloration means they blend perfectly into their environment and are seldom noticed unless they move, even then you need to be alert. They also wander around in dry sandy soils on sandy hillocks well away from water, where they live under leaf-litter, rocks, logs, or simply bury themselves in the sand.

Despite their aggressive hunting methods and powerful front legs, I have never been attacked, let alone nipped, even when I have picked them up, so fear not for your little pinkies, they are quite safe in their company.

Wingless Coreid Bug - Agriopocoris species

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Wingless Coreid Bug - Agriopocoris sp.

The genus Agriopocoris is a member of the Coreidae family along with such notables as the Clown Bug ( Insects - Bugs - Clown ) and a number of agricultural pests that cause spotting on soft edible fruits. However these wingless Australian species and the Clown Bug, plus others, restrict themselves to feeding on indigenous plants and are therefore no cause for alarm from commercial growers.

There are four species of Wingless Coreid Bug listed by the Australian Faunal Directory, of which two are to be found in the Esperance region, namely Agriopocoris dollingi and Agriopocoris froggatti, so presumably the individual shown above is one of these. Like all Bugs, they are equipped with modified mouth parts to penetrate and suck up the sap of plants, or in some instances like Assassin Bugs, the blood and soft tissues of animals. However the bugs in Coreidae are all sap suckers and many are highly specialised and restricted to specific host plants.

The bug above lives mainly in the soil or under leaf-litter, climbing plants like Acacia (Wattles) and eucalypts on which they feed. The adults appear like the nymphs of other coreids, but they remain wingless throughout their lives. The photographed specimen was around 1 cm (3/8") in length, which is apparently the norm for these insects, thus with their small size and secretive nature, it is not surprising they are seldom encountered.

Clown Bug - Amorbus rubiginosus

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Clown Bug - Coreidae - Amorbus rubiginosus

The Clown Bug is named after the bright colors of the juveniles (instars), rather than anything to do with the adult bug. However this group of sap sucking insects are also known as Eucalyptus Tip Bugs (as they feed from young new leaves), Gumtree Bugs (as they mainly feed on eucalypts), Sap Sucking Bugs or Squash Bugs. Compared to the instars, the adults are quite drab, with their orange backs being covered by their adult wings. The young bugs probably have strong coloration to act as a deterrent to predators, which would not be false advertising, as many insects that feed on eucalypts concentrate the toxins within themselves to become highly distasteful or even poisonous.

The body length of the 4th instar is around 15 mm (5/8") in length, whilst the winged adult will be a little over 20 mm (around 3/4"). This particular species is not a fast mover and will usually only when disturbed, shuffle to the reverse of the leaf it occupies, but can if required, retaliate to an aggressor by releasing a deterrent pungent smelling liquid from either side of the body (between the 2nd and 3rd pair of legs). However Amorbus rubiginosus is quite laid-back and not aggressive providing it is approached slowly and carefully.

These Clown Bugs including the adults are very specific as to the plants they feed upon, which in southern Western Australia is Eucalyptus pleurocarpa (previously known as Eucalyptus tetragona, a name no longer applicable). However the range of this particular bug is greater than the range of this eucalypt, so presumably it must feed on other species, although probably not many and certainly not fruit trees or ornamentals (there are six other closely related eucalypt species in WA that would match this bugs distribution and may also be its host). Clown Bugs are quite widespread in Australia and this species can be encountered in all States except Tasmania and the dry/hot center of the country, and although different host plants are preyed upon, there are only seven widespread species noted as hosts and all of them are eucalypts or close relatives.

The adult bugs have well developed rear legs, particularly the femur (thigh), but its only purpose seems to be to encourage females to mate (apparently they prefer males with sturdy thighs). The males will extend their hind legs at right-angles to give the females a good look and of course, if they have not lost a leg in fights with other males, so much the better with a match more likely. This display probably indicates to the female the health and vigor of males for mating and reproductive purposes.