'Amazing insects'

Two of many photos by Igor Ivanowicz:

Life is strange

Aquatic larva of Atherix ibis (a fly), magnified 25 times. Photo by Fabrice Parais

Why isn't the world full of pogonophora?

We could say that clade selection has occurred when a clade, such as the insects, spreads, diversifies and populates the world more successfully than another clade such as the pogonophora (no, you probably haven't heard of these obscure, worm-like creatures, and there's a reason: they are an unsuccessful clade!)...

Perhaps partly because of its segmentally modular architecture, the arthropod clade is good at evolving, at throwing up variation in multiple directions, at diversifying, at opportunistically filling niches as they become available. Other clades may be similarly successful because their embryologies are constrained to mirror-image development in various planes. The clades that we see peopling the lands and the seas are the clades that are good at evolving. In clade selection, unsuccessful clades go extinct, or fail to diversify to meet varying challenges: they wither and perish. Successful clades blossom and flourish as leaves on the phylogenetic tree.

-- Richard Dawkins speculates on 'the evolution of evolvability'. An extract from The Greatest Show... featured in the 300th edition of Edge.

'The mental powers of worms'

[Darwin wrote] "If worms have the power of acquiring some notion, however rude, of the shape of an object and of their burrows, as seems to be the case, they deserve to be called intelligent; for they then act in nearly the same manner as would a man under similar circumstances."

Where we find animal behavior that is closely analogous to what we would expect from humans in similar circumstances, and where there are no experimental grounds for distinguishing between them, the animals must be regarded as intelligent, to at least some degree, if humans are so regarded. Anything else, Darwin thought, is illogical and unfair. The best proof we have of the seriousness he attached to this principle is that he would not depart from it even in the case of worms. Considered in this light, Darwin's discussion of "the mental powers of worms" turns out to be not just the crankish musing of an old man, but a telling choice of example.

-- from Chapter 4 of Created From Animals: The Moral Implications of Darwinism by James Rachels (1990).

Plenty of room at the bottom

People see nature as trees, plants and vertebrates. Yet the world is run by little creatures most people have not heard of; 99 per cent of Earth's organisms are extremely small. For example, some of the most abundant and crucial land animals are the tiny oribatid mites, which are the size of a pinhead and look like a cross between a turtle and a spider. They are a linchpin organism of the environment, but 20 years ago when I set out to identify them no one had heard of them. Back then there were just two people in the US able to identify them. Fortunately one agreed to work with me. Yet we still don't know what the vast majority of oribatids do.

-- E O Wilson



A Eupheredermous Oribatid Nymph. Image from Macromite's blog, which quotes Richard Feynman: "A mite makes the seas roar."

P.S. 23 Aug: Archegozetes longisetosus can produce a holding force 1180 times its own weight, making it one of the strongest animals in the world relative to its mass (Heethoff and Koerner via Wiki).

Natural selection's finest

Two hundred and fifty million years of physiological fine tuning has produced a creature that will be around for a long time to come. Cockroaches, I'm afraid to say, will do well in the face of climate change.

-- George McGavin.

Inordinate posturing

the more baroque weapons, even though they look more fearsome, seem to cause lesser loss of life. The reason is that the more menacing weapons have often acquired a signaling role. Instead of risking their lives in mortal combat, males can assess each other’s strengths by sizing up a rival’s weapons, and decline combat if they seem outclassed. The ornate weapons also lend themselves to ritualized combat in which males may lock horns and assess each other’s strength without wounding each other.

-- from report on a hypothesis by Douglas J. Emlen and others.

Stockpiles of nuclear weapons large enough to destroy human life several times over may play a similar role...so long as they are not used!

image: Trypoxylus (Allomyrina) dichotomus

Not so super

Parallels between the ants and ourselves are striking for the light they shed on the nature of everyday human experiences. Some ants get forced into low-status jobs and are prevented from becoming upwardly mobile by other members of the colony. Garbage dump workers, for example, are confined to their humble and dangerous task of removing rubbish from the nest by other ants who respond aggressively to the odors that linger on the garbage workers' bodies.

-- Tim Flannery in a review article of The Superorganism by Bert Hölldobler and Edward O. Wilson.

All of a sudden, a pipe protruding into the drain above his head started spewing out water and human faeces that poured over his body.

-- Rupa Jha on 'My life cleaning Delhi's sewers'

Glass reef

This glass sponge (class Hexactinellida) created dense reefs in ancient seas that were shallow and warm. "The delicate animals were thought to exist only as fossils", says an article about a new illustrated Atlas of the Oceans, "until explorers in the 1990s discovered large reefs of living relics." The Sponge Reef Project says:

Siliceous sponge reefs or mudmounds occur several times in Earth history and they culminate in the Late Jurassic where they formed a discontinuous deep-water reef belt extending more than 7000 km. This reef system was the largest biotic structure ever built on earth. The largest reef of today, the Great Barrier Reef in Australia (2000 km), is relatively small compared to the Jurassic sponge reef belt.

Invasion of the body snatchers!

Parasites that control the minds of their hosts -- whether those hosts be fish, 'zombie' caterpillars, 'brainwashed' grasshoppers or even humans -- make for great headlines, resonanting all kinds of uncomfortable thoughts on the edge of consciousness. [1] In general, 'parasite' is a term of abuse in our culture, and scientists, notes Carl Zimmer [2], took a long time to get beyond this. Konrad Lorenz, for example, saw their only virtue as a warning to humans. "A retrogression of specific human characeristics and capacities conjures up the terrifying specter of the less than human, even of the inhuman". [3] But, argues Zimmer,

parasites are complex, highly adaptive creatures at the heart of the story of life. If there hadn't been such high walls dividing scientists who study life --the zoologists, the immunologists, the mathematical biologists, the ecologists -- parasites might have been recognised sooner as not disgusting, or at least as not merely disgusting.

Parasites find themselves a vast number of ecological niches, he notes; they even find out a way to parcel out the human eye: one species of worm in the retina, one in the chamber, one in the white of the eye, one in the orbit. Zimmer also suggests that an assertion made back in 1845 by Johann Steenstrup, a pioneer in the study of flukes, is still relevant:

I believe that I have given only the first rough outline of a province of a great terra incognita which lies unexplored before us and the exploration of which promises a return such as we can at present scarcely appreciate.[4]

Footnotes:

1. Humans fear parasitic infestations, of course, and often with good reason. At least as disturbingly, we apply the term to other people and groups of people, sometimes with horrendous political consequences. And there is sometimes for some people a lurking sense that we ourselves as a species are parasitic (the borderland between parasite and predator not being well defined).

2. Parasite Rex (2000). The book is sensationally subtitled Inside the Bizarre World of Nature's Most Dangerous Creatures.

3. According to Kenan Malik's account (Man, Beast and Zombie. 2000), Lorenz saw civilisation as a degradation of the natural state of Man, the great hunter of the Upper Paleolithic. Lorenz was, notes Malik, highly sympathetic to Nazi ideology.

4. Just one example of a recent step to better understand and manage a remarkable protozoan is the work by Hugo D. Luján et al reported here. Unlike most of its fellow eukaryotes, giardia has no mitochondria. Even stranger, each giardia cell has two nuclei.

Image: hookworm

From the shallows

Zooillogix is finally living up to the 'x' in our namesake. We have discovered a microscopic animal that engages in lesbian sex with its dead female friends in order to obtain DNA and thus survive to reproduce.

Zx. has humourously repackaged for Xmas a paper by Gladyshev et al. that actually dates from May 08, and was reported at the time. Calling what is involved 'sex' is a real stretch. Anyway, the findings do seem to shed light on the apparent conundrum that bdelloid rotifers have survived more than 80 million years without sex.

News flash

Evolutionary biologists have studied synchronous flashing [of fireflies] for 200 years...and it remains a mystery. But it is a spectacle that may be disappearing.

-- from Ban Lomtuan Journal by Seth Mydans.

Crabs

Here, for no particular reason, are three images of crabs:


Hermit crab with anemone (via Reinhold Leinfelder).


Coconut crab (via Daily Kos Marine Life Series).


Feather star crab on its host (from the feature A world of crabs on one tiny island, via Zooillogix ).

Trilobite beetle of Laos

Hat tip, Grrlscientist

Urchins

Pohls sea urchins found off Lizard Island (see New species revealed on Great Barrier and Ningaloo reefs). "The researchers spotted about 300 soft coral species, up to half of which they think are new to science, as well as dozens of small crustacean species, likewise thought to be unknown."

Bears in space

My other blog has long and proudly carried a link to Tardigrades in Space. Now, the refereed paper is in (Tardigrades survive exposure to space in low Earth orbit; see also news report).


One small step for a waterbear. A giant leap for waterbearkind!

(Space emissary from another bear here.)

P.S. The Other 95% has this covered:

Vacuum ? bah,
Freezing ? Ho-hum
Dessication? So what!
Uh, oh cosmic radiation?!
Nope got that covered too.
Cosmic radiation plus direct solar radiation?
Ok, that one hurts.
But still enough of us will survive and quickly start up again!!

P.S. 5 Dec: another kind of bear in space

Flower power

[By] increasing the numbers of male [wasps], [the orchid] could even make [them] a bit more desperate and less discriminating — another potential advantage for an orchid trying to fool a male into giving the not-quite-right-looking fake female sitting immobile inside its petals a try.

-- from Tongue Orchids’ Sexual Guile: Utterly Convincing. A slave to love, indeed.