Everybody loves the cute animals. Just mention the word ‘panda’ or ‘meerkeet’ or ‘kitten/puppy’ and watch everybody go all warm and runny. But say ‘roach’ or ‘rat’ or ‘squid or ‘parasite’ and watch the upper lip curl. But who’s to say which of these animals are more important in the overall scheme of things? Every animal on Earth fills a niche and fulfills a purpose or it wouldn’t be here. So today we’re going to talk about some of those animals that do NOT evoke the “Aw-w-w, how cute!” expression. And you just might learn something!
If I were making a list of the animals on my personal top 10 ‘love to hate’ list, I suspect the cockroach would be right up there at #1. But don’t sell the cockroach short. Recent research has revealed some very interesting (in the Chinese sense of the word) things about this astounding insect.
QUICK! STEP ON IT!
Researchers at the University of Queensland in Brisbane, Australia recently examined cockroaches to see whether they change their breathing patterns in response to changes in carbon dioxide or oxygen concentration, or humidity.
They discovered that changes in carbon dioxide and oxygen concentrations didn’t have a whole lot of effect on a roaches breathing habits but they did find that the widely loathed insects can hold their breath to save water.
They concluded that cockroaches close the spiracles through which they breathe primarily to save water. In dry environments the insects took shorter breaths than in moist conditions. They also discovered that when cockroaches are resting, they periodically stop breathing for as long as 40 minutes, though why they do so has been unclear.
The study deals a blow to the theory that cockroaches hold their breath to survive underground, where CO2 levels can be poisonous. Nor did the study support the idea that cockroaches hold their breath to avoid damage to their body tissue from chemical reactions with oxygen.
The nifty breath-holding adaptation has allowed cockroaches to colonize drier habitats. Cockroaches also have a waxy coating that helps hold in the water. One of the easiest ways to kill cockroaches in drier climates is to spread kitty litter made from diatomaceous Earth in your cabinets. Diatomaceous Earth is made of diatom shells and diatoms make their shells of glass. When a cockroach runs over these tiny pieces of broken glass, it scores the waxy coating on their shell and they dehydrate and die. That doesn’t work here, unfortunately, it’s too wet.
Cockroaches evolved in the humid conditions of a rainforest, but they are definitely adaptable and can cope in a wide range of environmental conditions. Will the sun ever set on the empire of the cockroach? Not any time soon. Cockroaches have been around for 250 MILLION years. They survived the dinosaurs and they will, no doubt, survive us!
So, we’ve established that, although nobody likes them, cockroaches will probably outlive humans as a species. This leads us to the next icky topic of discussion: parasites. If I’m making that list with the cockroach at the top, parasites certainly rank up there in the top ten. Parasites (specifically fleas) are the subject of the world’s shortest poem. And the poem is: “Adam had ‘em!” Parasites have certainly been around for a long time, but what happens when their hosts go extinct?
THE HIDDEN COST OF EXTINCTION
We wring our hands and gnash our teeth over the loss of endangered species like the panda or the polar bear. But what happens to the parasites hosted by endangered species when they go extinct? And although most people would side with the panda over the parasite, which group should we worry about more?
Researchers from North Carolina State University recently published a paper that examines the concept of co-extinction, or the domino effect of extinctions caused by species loss. For example, each fig species tends to be pollinated by a single fig wasp. The loss of the tree should cause the extinction of the wasp and vice versa. Mathematical models suggest that co-extinctions due to the actions of humans are very common, the paper asserts. Yet, surprisingly enough, there have been few reported cases of co-extinction in the scientific literature.
The models suggest thousands of co-extinctions have already occurred and that hundreds of thousands may be on the horizon. But few such events have been observed. The scientists aren’t sure if the co-extinctions are happening and not being tracked, or if parasites are better at switching partners than we give them credit for, or something in between. Maybe some of the ‘specialized relationships’ – like between the figs and fig wasps – aren’t so specialized.
In addition, the researchers say that the models predict that the number of parasite extinctions should be much larger than the number of host extinctions since the diversity of parasitic or affiliated species – which may include things like viruses, bacteria ticks, lice mites and a whole host of internal parasites — is several orders of magnitude greater than that of their hosts.
This numbers game alone presents strong evidence that suggests co-extinctions are more important than the original host extinctions themselves. But the paper also examines other costs of co-extinction – including the losses of biological diversity, unique species traits and what we can learn about evolutionary history.
But that’s not the really scary part. According to the researchers, there’s a distinct possibility that declines in host species could drive parasite species to switch onto alternative hosts, which in turn could escalate the rate of emerging pathogens and parasites both for humans and our domesticated animals and plants. Simply put, when a host becomes rare, its parasites have two choices: jump ship to another host or go extinct. Either situation is a problem.
The researchers noted that the regions where new human diseases like bird flu, are emerging coincide with the regions where the most mammal and bird species are endangered. We’ve talked for a long time about the negative consequences of the endangerment of the species we love but getting stuck with their parasites is a consequence nobody bargained for!
And now we turn our attention to a much more loveable animal than cockroaches and parasites, but you’ll have to admit, that octopi probably still fall in the ‘ugly’ category. And this tale relates the story of how one hapless octopus turned up in the most unlikely of places. As a fossil.
DEM BONES, DEM BONES, DEM DRY BONES
When the story broke several years ago about the ‘hobbits’ found on Flores Island in Indonesia; I was taken by this tale of miniature hominids. But what really fascinated me is that the news feeds kept referring to the ‘hobbit fossils’. I kept wondering what the real story was because fossils simply don’t form in tropical conditions. The constant rainfall keeps the bones from ever acquiring the minerals that turn them into rocks.
And when I finally read the scientific reports I discovered I was right. The Flores skeletons may have been over 80,000 years old, but they were NOT fossils. They were 80,000 year old bones. If you think about it though, fossils are almost always bones. So, what are the odds that you can find a fossil of something that has no bones? Read on.
Even if you’ve never met an octopus in the flesh, the eight arms, suckers, and sack-like body are almost as familiar a body-plan as the four legs, tail and head of cats and dogs. Unlike vertebrates, however, octopi don’t have skeletons. While this allows them to squeeze into impossibly small spaces, it does create problems for scientists interested in evolutionary history. When did octopi acquire their characteristic body-plan, for example? Nobody really knows, because fossil octopi are rarer than, well, pretty much any rare thing you care to mention.
The chances of an oct
opus corpse surviving long enough to be fossilized are so small that prior to this discovery only a single fossil species was known, and from fewer specimens than the eight legs of an octopus.
The body of an octopus is composed almost entirely of muscle and skin, and when an octopus dies, it quickly decays and liquefies into a slimy blob. After just a few days the carcass disappears entirely. The result is that preservation of an octopus as a fossil is about as unlikely as finding a fossil sneeze, and none of the 200-300 species of living octopus has ever been found in fossilized form. Until now, that is.
Paleontologists have just identified three new species of fossil octopus discovered in Cretaceous rocks in Lebanon. The five specimens are 95 million years old but, astonishingly, preserve the octopuses’ eight arms with traces of muscles and those characteristic rows of suckers. Even traces of the ink and internal gills are present in some specimens.
"These are sensational fossils, extraordinarily well preserved," says Dirk Fuchs of the Freie University Berlin, lead author of the report. But what surprised the scientists most was how similar the specimens are to modern octopus: "these things are 95 million years old, yet one of the fossils is almost indistinguishable from living species." This provides important evolutionary information.
The more primitive relatives of octopi had fleshy fins along their bodies. The new fossils are so well preserved that it’s possible to tell they didn’t have these fleshy fins. This pushes back the origins of the modern octopus by tens of millions of years, and while this is scientifically significant, perhaps the most remarkable thing about these fossils is that they exist at all.
Keuppia levante — one of the new species of fossil octopus discovered in Cretaceous rocks in Lebanon. (Credit: Dr. Dirk Fuchs)
Animals. They don’t all have to be loveable to tell us some pretty interesting things about themselves, the Earth and us! Cruise on over to the Deep Website at www.thedeepradioshow.com to learn more about ugly animals and many other topics. Enjoy!