A World of Beetles

The great British-born biologist JBS Haldane famously once said (well perhaps, it seems surprisingly uncertain) "If one could conclude as to the nature of the Creator from a study of creation it would appear that God has an inordinate fondness for stars and beetles." He was referring to the sheer, mind-numbing numbers of beetles (and of course stars). At least 400,000 species of beetle are known, and no-one imagines that that's anywhere near all of them. For perspective consider that all species of vertebrates number less than 70,000 (and half of them are fish). I've mused before that if all those vertebrates vanished overnight, the overall biodiversity of the planet would not be greatly diminished.

A very spiffy beetle whose identity is beyond my limited knowledge, though on
reflection it does remind me of some of the Australian Net-winged Beetles, Family Lycidae.
Sanaga River, Cameroon.

By current information, beetles account for some 40% of all insect species, though recently claims have been made that the Order of flies, and/or the one that comprises ants, bees, wasps and sawflies, are even more numerous, but so far there are not the figures to support this. Perhaps even more stunningly, they currently represent about 25% of all animal species! Needless to say then, this post is going to be pretty superficial, even apart from the depth of my ignorance on invertebrates. In my defence though I do try to educate myself in the ways of the wonderful small world. 

With such a huge group it is almost impossible to generalise, but aside from the general insect structure of three body segments each with a pair of legs, and a pair of antennae, a characteristic of most beetles is the presence of a hard pair of forewings known as elytra, which are not used in flying but cover and protect the functional hindwings. When a beetle is about to take flight it lifts the elytra up and out of the way, and releases its wings. Indeed the name of the beetle Order, Coleoptera, is from the Greek for 'sheath wings'. These elytra, and of course the fancy antennae and the six legs, are obvious in the Cameroon beetle above. Mouthparts move from side to side, rather than up or down. Many of the Order of bugs (Hemiptera), which includes cicadas, can superficially resemble a beetle from above, but underneath a long tubular mouth structure gives them away. 

This is a glorious female Golden Stag Beetle Lamprima aurata, which apparently expired
on our home balcony rail one summer. The horizontal jaws can be seen if you
click on the photo to enlarge it.
Below, for comparison, is a sap-sucking hemipteran from Central Australia. It's a
pretty washed-out photo, scanned from an old slide, but it's the best illustration I
have of the tubular mouth part, here in action.

Most beetles have a complex life cycle, with a four-stage metamorphosis of egg, pupa, larva and adult.

There are some 20,000 beetle species known from Australia (plus many more to come, if only we can manage to fund taxonomy properly, a seemingly forlorn desire). The largest Australian Families, according to the Australian Museum in Sydney, are weevils (the largest animal family in the world) with 6000 Australian species, scarabs (3000), leaf beetles (3000), ground beetles (2500), rove beetles (1600), darkling beetles (1500), longicorn beetles (1200) and jewel beetles (1200). 

My goal today is simply 'introduce and enjoy', based on my own meagre photo files. It's not at all impossible that I've made mistakes in my identifications though I've tried not to - as ever I welcome advice and corrections. The simplest way might be to go through the Family list above, though I don't have photos for all of them (or I might, but if so they're among the ones that I can't recognise!).

Weevils: Family Curculionidae is among the most recognisable of beetle groups, due mostly to the presence of a rostrum (or 'snout'), a distinctive extension of the head. Another distinctive characteristic is the 'elbowed' antennae, formed of a long base with a segmented extension at an angle to it. This active little group at Shark Bay, WA, show both these characters.

They also well demonstate sclerotisation, the process of hardening and darkening
the cuticle by biochemical processes. Apart from physical protection it
also provides protection from dehydration in arid environments.

A tiny and unusually colourful weevil on a Dodonea fruit in Trephina Gorge,
East MacDonnell Ranges/Tjoritja, Central Australia.

Demonstrating the ubiquity and hardiness of beetles, this little weevil
was on a fallen tree trunk in Ushuaia NP, Tierra del Fuego in the far
south of Argentinian Patagonia, some 1200k south of Hobart.
We were told at the time that it was sacred to the indigenous inhabitants,
but I can find no reference to that. This is only one of 40 weevil
species in the archipelago.

In addition there are related families referred to as weevils, including the attractive elongate belid weevils, family Belidae.

 

 Rhinotia sp. (I'm pretty sure either R. suturalis or R. brunnea),
Bluetts Block, a dry forest remnant on the edge of Canberra.

Scarabs: Family Scarabaeidae includes the scarab beetles sacred to the ancient Egyptians, dung beetles, Christmas beetles and pasture chafers. The best-known and most colourful of these are the Christmas beetles, genus Anoplognathus, whose adults emerge from the soil in December - or at least they did until recently, when numbers have dropped alarmingly. The larvae feed on grass roots, whereas adults feed on eucalypt leaves. When numbers were high, eucalypts could be temporarily partially defoliated by them.

Anoplognathus sp., Canberra. The strong claws presumably assist in clinging to eucalypt leaves.

A large and (formerly) common Christmas beetle Anoplognathus pallidicollis,
here at Beowa NP, far south coast NSW.

Some scarabs are surprisingly colourful, including the chafers and flower chafers (I'm not going to bother you with subfamily names, not least because they're still under debate).

Diphucephala is a genus of around 70 species of chafers found over the whole continent; the larvae feed on roots and the adults on foliage.

Diphucephala on a daisy in the Snow Gum woodlands in Namadgi National Park,
above Canberra. The flower spider probably considers the beetle's armour a bit beyond it.

In summer in the ACT high country this Diphucephala can be abundant,
especially on the peas shrub Leafy Bossiaea B. foliosa.

Fiddler Beetle Eupoecila australasiae, one of the flower chafers, on Bursaria spinosa,
Jerrabomberra Wetlands, Canberra. This one is common on flowering native shrubs in summer.

A very furry little scarab on a fern in Kangaroo Valley, NSW.

I was told at the time that this pretty little fellow at Tambopata in the south Peruvian
Amazonia was a dung beetle, which has just been confirmed (thanks Susan, whose comment is below).

Another handsome little scarab that I don't have a name for,
this time on the window of our vehicle in Ngorongoro Crater, Tanzania.

And some scarabs are among the most impressive of all beetles. Some of these wonderful beasts live in Australia but hitherto my only encounters with them have been overseas. The members of one splendid subfamily are called rhinoceros beetles, for the impressive 'horn' on the head of the males, used for sparring with other males during courtship.

Male rhinoceros beetles in lowland rainforest in Costa Rica (above)
and in Andean cloud forest in Ecuador (below).

The most impressive beetles I've ever seen however were in a garden in the central ranges of Costa Rica.

Elephant Beetle Megasoma elephas, some 10cm long. They live on tree sap and fallen fruit.

Hercules Beetle Dynastes hercules; they can grow up to an amazing 17cm long,
though this one wasn't quite that size. Surprisingly it can still fly, one of the very
largest insects to do so. Their larvae help break down fallen logs in the forest.

Leaf beetles: Family Chrysomelidae is a large and varied family of mostly small, often rounded beetles with short antennae. Most adults feed on foliage of eucalypts and acacias, as do many larvae though some feed on drier material on the ground. Paropsine or tortoise beetles are familiar examples.

Larvae of Paropsis sp. on eucalypt leaf. They are often mistaken for 'spitfire caterpillars',
which also live on eucalypt leaves, but are the larvae of species of sawfly. These
larvae defend themselves with glands containing hydrocyanic acid, a pretty
convincing defence! I read that a dose of the larva's defence can kill a meat ant outright.

Adult Paropsis sp. also chewing on a eucalypus leaf, ranges of south coastal NSW.

This one, I'm pretty sure, belongs to a different sub-family (Cryptocephalinae), though that's as far as I can go.

Leaf beetle chewing its way down the edge of an acacia phyllode in
Whyalla CP, South Australia.

In the same sub-family are these funny little larvae which I came across many years ago on a management track in Tallaganda NP east of Canberra. They were chewing on the green eucalypt leaf (though why it was on the ground I have no idea). 

If you click on the photo you can see the heads of the little munchers protruding
from their little protective cases.

This is the story, briefly, as explained to me at the time by Kim Pullen of CSIRO Entomology. As the female beetle laid each egg on the ground, she caught it in the 'foot' of her rear legs and coated it in droppings, which are composed of eucalypt leaf material. When the egg hatched, the little beetle larva broke a hole at the front of the case and with the assistance of its front 'legs' moves about the forest floor eating the litter. As they grow they add to their homes with their own droppings, though I can't quite envisage the mechanism for this.These homes provide both physical protection and effective camouflage in the litter. It has been suggested that these atypical forest floor larvae play an important part in the breakdown of forest litter. Eventually they pupate within the case before emerging as adult beetles.

 

There are species of leaf beetle in Australia though which are not interested in hard eucalypt or acacia foliage. Here is one which specialises in orchids, specifically the big showy, often summer-flowering hyacinth orchids Dendrobium spp. Logically enough it is known as the Orchid or Dendrobium Beetle.

Stethopachys formosa on Hyacinth Orchid Dipodium punctatum. The adults chew up
leaves, flowers, buds and seedpods then, adding insult to considerable injury, its
larvae eat the remaining leaves and stem.

Finally for leaf beetles, a couple of attractive little ones from Costa Rica.

In lowland Caribbean rainforest.

On a telescope in a garden on the edge of San José. Maybe it was trying to look bigger...

Longicorn Beetles; Family Cerambycidae is a recognisable large group of beetles with long antennae and elongated bodies. Their larvae mostly bore into wood, living or dead, while the adults may, according to species, eat bark, wood, foliage, pollen or sap.

It's pretty clear what this one is eating, and how efficiently it's doing it.
It's a Leopard Longicorn Beetle Penthea pardalis, from near Cooktown in north Queensland.
Its larvae bore into living acacias and it has somehow found its way to overseas
acacia plantations where it has made itself extremely unwelcome.

Here are a couple more longicorns, though I have no idea of their identity beyond that.

 

Ecuadorian Amazonia, at night.

 

In our cabin at Cobbold Gorge in the Gulf Country of tropical Queensland.

On Mount Cameroon.

Jewel beetles: Family Buprestidae contains some of the most beautiful of all beetles, though over the years I seem to have been remarkably inept at finding them! (And to be honest I'm so unfamiliar with them that I'm not entirely sure of my identification here, so feel free to correct me.)

On acacia flowers,  Leeuwin Naturaliste NP, south-western Western Australia.

On Gaultheria sp. Family Ericaceae, Chilean Patagonia.

 

Unidentified jewel beetle that we we found dead on a mossy
log in Kangaroo Valley, NSW. It's missing its antennae. My thanks to Susan (comment
below) for identifying the family.

Other Australian families are smaller, though some are still substantial, others contain familiar species. Here are some of them.

 

Ladybirds: Family Coccinellidae is a family of readily recognised little hemispherical beetles, often red or yellow and sometimes spotted. They are ferocious predators of many small insects regarded as garden pests, such as aphids, mites and scale insects. There are about 500 Australian species. One particular curiosity of ladybirds is their propensity to form huge swarms of thousands of individuals, apparently when feeding has been good and they have good fat reserves. They congregate at a high point such as a mountain or a tower, mate and then scatter again. Here are a few Australian ladybirds.

Transverse Ladybird Coccinella transversalis, Australia's commonest ladybird, which
is also found as far afield as India. This one was in the Brindabella Ranges above Canberra.

Harmonia sp., among the Snow Gums in the Brindabellas.

I'm guessing Harmonia for this one too, in the Tahune Forest south of Hobart,
but am not at all sure.

Stag beetles: Family Lucanidae has nearly 100 species of stag beetle in Australia, featuring enlarged, often toothed, mandibles especially in males, and oddly angled antennae. The mandibles are supposed to resemble a deer's antlers, but I guess it's all in the eye of the beholder! Females are generally less dramatic in form. Many forest species spend their lives under rotting logs and thus are very rarely seen.

Male Stag Beetle in the Crocker Range, Sabah, Malaysian Borneo, foreground.
The 'antlers' and bent antennae are evident. The one behind appears to be a less-endowed female.

Stag Beetle, near Machu Picchu, southern Peruvian Andes.

Female Golden Stag Beetle Lamprima aurata, northern Tasmania. We found her
dead and her antennae are missing, but the colouration was still beautiful.
I think these are sometimes mistaken for Christmas beetles.
Most stag beetles are dull coloured - but not all!

Soldier Beetles: Family Cantharidae is known best for a few species of the genus Chauliognathus, in my part of the world especially for the Plague Soldier Beetle C. lugubris which gathers in huge numbers in summer. The 'plague' part of the name is most unfortunate as they do no damage, but are in fact beneficial in being major predators, both as adults and larvae, of aphids, plant-chewing caterpillars and other larvae, grasshopper eggs etc, as well as feeding on pollen and nectar. The gatherings are for mating purposes, and many of the animals in such a swarm are coupled. They have a surprisingly soft body, but protect themselves by exuding some unpleasant alkaloids, so they are best left alone.

Plague Soldier Beetles, above and below, swarming at the
Australian National Botanic Gardens.

Chequered Beetles: Family Cleridae are mostly predators of other beetles in particular, both adults and larvae, but some feed on pollen or scavenge animal carcasses. Many are found on flowers, either for the pollen or hunting pollinating insects.

Chequered beetle Eleale sp. and a flower spider on a Silver Snow Daisy Celmisia sp.,
among the Snow Gums high in Namadgi NP near Canberra.
Double trouble for visiting pollinators!

Net-winged Beetles: Family Lycidae are distinctive, except for various other species (beetles such as soldier beetles and jewel beetles, as well as some moths) which mimic them to gain protection from the lycids' well-earned reputation for being distasteful and toxic. Some adult lycids feed on nectar while others don't live long enough to need to feed.

Porrostoma rhipidum mating, Namadgi NP. This species is widespread in the
moister parts of Australia.

Some Porrostoma species are very gregarious and cluster on flowers like this
congregation on eucalypt flowers in Canberra.

A truly remarkable genus of lycids is found in India and south-east Asia. The females retain their larval form, and may be up to 8cm long in some cases, while the males are much smaller 'conventional' beetles.

Female trilobite beetle Platerodrilus sp, Mount Kinabalu, Sabah, Malaysian Borneo.

For the rest I offer a few beetles whose families I was uncertain of (ie for the most part I didn't have a clue!) until Susan kindly helped me out with a couple (plus a couple above that she identified). The first is Australian, the others are from three different continents. Identity aside I thought they are attractive and/or interesting enough to introduce you to.

This one, from King's Canyon in Central Australia is, I now know thanks to Susan,
one of the carrion beetles, Family Silphidae, which indeed feed on carcasses.

And finally some anonymous but impressive overseas species.

Amber Mountain, Madagascar. I did wonder if it was actually a bug, Oder Hemiptera, though I
fancy I could see some beetle mouthparts, but Susan confirmed that its numerous antennal
segments make it a beetle.

Northern Andes, Ecuador.

Inland rainforest, Sarawak, Malaysian Borneo, at night.

At that's the end of our beetle journey for today. I hope you've enjoyed it and learnt something - I have certainly done both. Thanks for accompanying me, and I hope you now have more of an eye for the amazing beetles that are one of the dominant forms of life on earth.

NEXT POSTING THURSDAY 23 MAY

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