About Me

My photo

I've been a Canberran since moving here from Adelaide on the first day of 1980. I now live in suburban Duffy with my partner Louise Maher, ABC 666 radio and on-line journalist. Among my early memories is following Sleepy Lizards (Shinglebacks) around the paddocks north of Adelaide, guarded by the faithful bull terrier. I have always been passionate about the natural world, trying to understand how it works, how the nature of Australia came to be, and sharing those understandings. My especial passions are birds, orchids and mammals. For much of my life I have been a full-time naturalist, running bush tours, writing books etc, doing consultancies, presenting a regular radio slot on local ABC, chairing a government environment advisory committee and running adult education classes. Recently I have eased back somewhat, but am still writing, teaching, doing some radio work and running overseas tours - as part of my fascination with our Gondwanan origins I've been running tours to South America for the past decade. I was awarded the Australian Plants Society Award in 2001 and the Australian Natural History Medallion in 2006, both for services to education and conservation.

Tuesday, 11 March 2014

Camouflage #2; spinelessly hiding

Last time I introduced the concept of camouflage in nature by looking at some vertebrates - mammals, birds, reptiles and frogs - which have evolved some superb patterns, shapes and postures to disappear into the background. As promised, today I'm going to continue the theme by putting the magnifying glass onto some smaller animals, invertebrates - if I can find them!

Camouflage is for the benefit of both hunters and hunted, and small animals are always potential prey, irrespective of whether they are also hunters themselves. The first few examples then are of animals which live by catching other animals, but they must also stay out of sight from the myriad of larger animals, vertebrate and invertebrate, which would devour them if given a chance. The first is one of my favourites - and I will confess that I saw it only after photographing the flower!
The flower spiders, Diaea spp., family Thomisidae, comprise some 80 species of specialised Crab Spiders,
found on every unfrozen continent, with over 30 of them native to Australia.
They lurk in and around flowers, aided by cryptic colouring (ie often brightly coloured!), and hook
unwary pollinators with their curved front legs.
This one, in the National Botanic Gardens in Canberra, is hiding, albeit in the open,
on a common local daisy, Chrysocephalum semipapposum.
A Western Australian crab spider, probably Diaea sp., on, appropriately, a spider orchid,
Caladenia (or Arachnorchis) longicauda.
The characteristic powerful jagging two front pairs of legs are obvious here.
Spiders which hunt elsewhere must also hide, including those which guard a web; a spider in a web in the day is very vulnerable to birds in particular. This one was beautifully camouflaged on the tree bark at the edge of its web.
Eriophora transmarina, family Areneidae, Gungahlin Hill Nature Reserve, Canberra.
The pattern is surprisingly reminiscent of the Tawny Frogmouths, hiding against an identical background,
that featured in my last posting.
And the spiders which do not ambush or build webs, such as the ground-ranging wolf spiders, must also take care not to be conspicuous from above.
Wolf Spider, family Lycosidae, White Dam Conservation Park, South Australia.
The dark patches resembling shadows, and the grey legs and abdomen, break up the outline superbly.
Praying Mantises, like the flower spiders, often hide in foliage or by flowers to trap pollinators; here too resembling the background colour is a big help.
It worked for this one, which is munching on a small fly!
Corang River, east of Canberra.
If you're a grasshopper or moth however, there is no question where you come in the food chain, and while it's not the only defence, camouflage can only help. Here are some examples that impressed me.
This grasshopper, in stony country near Broken Hill, western New South Wales, would have made my point better,
and been a lot safer, if it had stayed on the paler rocks, but you can see how well it would vanish there.
This beauty, in a granite landscape in Torres del Paine National Park, Chilean Patagonia,
was doing a much more convincing job.


As was this one north of Maroua, in the Sahel of Cameroon.
It is also an excellent example of the importance of orientation.
The camouflage of this beautifully mottled Hamadryas sp., above and below,
works equally well on different backgrounds.
Cerro Blanco Reserve, Guayaquil, Ecuador
 

Like the Broken Hill grasshopper above, this lovely moth wasn't on the perfect background for its pattern, but we can imagine the effectiveness if it was on a licheny tree trunk as above.
San Pedro area, Rio Madre de Dios, Peru.
A variant is to suddenly 'vanish', by flashing coloured legs (some grasshoppers) or wings (some butterflies and moths) in flight, and suddenly hiding them on alighting. The simultaneous appearance of a big eye is an additionally unnerving experience for their puzzled pursuer!
Owl Butterfly, Caligo sp., family Nymphalidae, Sacha Lodge, Ecuadorian Amazon.
Above and below.

Insect larvae are of course even more vulnerable, and many caterpillars try to stay hidden while feeding in the open.
Caterpillar on Snow Gum twig, Namadgi National Park, near Canberra.
And finally for today, it's not just land vertebrates that need and adopt camouflage, though I'm not in a position to record these for the most part. This crab however, photographed from a mangrove boardwalk, really caught my attention only when it moved.
Huskisson, New South Wales south coast.
See how perfectly the carapace pattern matches that of the sun of the sand grains!
Ghost crab, Tempurong Beach, Sabah.
This one was aware of me being too close and was moving, but flat against the sand it disappeared.
 I've had fun with this, and I hope you have too. Back next time with something completely different; something for the Gunn lobby!

BACK ON THURSDAY


No comments: