Invertebrates
grrlscientist | October 16, 2008tags: fiddler crabs, marine life, photography, Image of the Day
Fiddler crabs, photographed at Bolivar Flats, Texas,
Image: Joseph Kennedy, 22 August 2008 [larger view].
Nikon D200 ,Kowa 883 telescope with TSN-PZ camera eyepiece 1/500s f/8.0 at 1000.0mm iso400.
edyong | October 9, 2008
Throughout the day, our skins are constantly sending out messages that we are completely oblivious to. The message is written in chemical form and it says, "Here I am. Come and get me". We neither see nor hear these signals but other creatures do, and they slither, crawl and swim our way in response.
These creatures are nematodes, a group of worms that are some of the most common animals on the planet. The vast majority of nematode species are parasites, and hundreds of species count humans among their potential hosts. In the developing countries of the tropics and sub-tropics, parasitic…
clock | October 3, 2008Apparently yes: Freshwater Farm Ponds Turning into Crab Farms:
North Carolina's native blue crab population has been at historic lows since 2000. Dr. Dave Eggleston, director of NC State's Center for Marine Sciences and Technology (CMAST) and professor of marine, earth and atmospheric sciences, looked at various methods for helping the population recover. He hit upon a solution which not only reduces pressure on existing crab populations, but also benefits farmers looking to diversify their crops: using irrigation ponds on farms to grow blue crabs.
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Eggleston and…
edyong | September 29, 2008
Two strangers are having a normal conversation in the middle of a large crowd. No one else can see them. No one else can listen in. Thanks to advanced gadgetry, they are talking in coded messages that only they can decipher. These invisible conversationalists sound like they've walked out of a Bond film. But they are entirely real, and their skill at secrecy is biological, not technological. They are squid.
Squid and their relatives, the octopus and cuttlefish, are masters of concealment. They have the most sophisticated camouflage abilities in the animal kingdom and use them to avoid…
edyong | September 19, 2008Genetically modified crops have received a frosty welcome in the UK, and more widely in Europe. Those opposed to such crops worry (among other things) that they could affect the flora around them by outcompeting them or by spreading their altered genes in a round of genetic pass-the-parcel. Now, a new study shows that genetically-modified crops does affect surrounding plants - but in a positive way.
Kong-Ming Wu from the Chinese Academy of Agricultural Sciences found that genetically modified cotton designed to kill an insect pest can also protect other species plants from its jaws. In…
edyong | September 10, 2008The forests of east Asia are home to giant honeybees. Each one is about an inch in length and together, they can build nests that measure a few metres across. The bees have an aggressive temperament and a reputation for being among the most dangerous of stinging insects. Within mere seconds, they can mobilise a swarm of aggressive defenders to repel marauding birds or mammals. But against wasps, they use a subtler and altogether more surprising defence - they do a Mexican wave.
Wasps, and hornets in particular, are major predators of bees and the largest ones can make even the giant bees…
edyong | September 8, 2008 In September last year, a team of scientists launched a squad of tiny animals into space aboard a Russian satellite. Once in orbit, the creatures were shunted into ventilated containers that exposed them to the vacuum of space. In this final frontier, they had no air and they were subjected to extreme dehydration, freezing temperatures, weightlessness and lashings of both cosmic and solar radiation. It's hard to imagine a more inhospitable environment for life but not only did the critters survive, they managed to reproduce on their return to Earth. Meet the planet's toughest animals - the…
clock | August 26, 2008
Thanks Bill for drawing my attention to iNaturalist which has the makings of an awesome site!
What is it?
It is essentially a Google Map where people can add pins every time they see an interesting critter: a plant, fungus, animal, etc. What is recorded is geographical coordinates and time when it was posted.
Moreover, people can link from the pins to pictures of the sighted critters if they upload them on Flickr (nice way to interlink existing social networking sites instead of reinventing the wheel). And they can put additional information, e.g., description of the habitat where they saw…
edyong | July 22, 2008A complete ban on fishing can save coral reef communities in more ways than one. A few weeks ago, I blogged about a study which found that the coral trout, a victim of severe overfishing, was bouncing back in the small regions of the Great Barrier Reef where fishing has been totally forbidden. It certainly makes sense that fish will rebound when fishing ceases, but a new study reveals that the bans have had more indirect benefits - they have protected the corals from a predatory starfish.
The crown-of-thorns starfish (Acanthaster planci) is a voracious hunter of corals and a massive problem…
edyong | July 21, 2008
Social spiders are an arachnophobe's nightmare. While the vast majority of spiders work alone, the odd few live communally and cooperate to hunt and feed. Their numbers, along with the massive webs that they all have a spinneret in creating, allow them to tackle prey far larger than themselves. The aftermath of a kill opens up new conflicts for the spiders that other cooperating hunters like lions or wolves don't share. They don't divide up the carcass to eat separately, for like all spiders, they digest their prey outside their bodies.
All the colony members spit their digestive enzymes…
edyong | July 19, 2008
In April 1998, an aggressive creature named Tyson smashed through the quarter-inch-thick glass wall of his cell. He was soon subdued by nervous attendants and moved to a more secure facility in Great Yarmouth. Unlike his heavyweight namesake, Tyson was only four inches long. But scientists have recently found that Tyson, like all his kin, can throw one of the fastest and most powerful punches in nature. He was a mantis shrimp.
Mantis shrimps are aggressive relatives of crabs and lobsters and prey upon other animals by crippling them with devastating jabs. Their secret weapons are a pair…
edyong | July 12, 2008
There is an old joke that if Spider-Man has the powers of a spider, he really ought to be shooting webs from somewhere less salubrious than his hands. In the films and comic books, Peter Parker is empowered with the powers of a human-sized arachnid through a spider bite. He effortlessly scales walls and ceilings and shoots sticky webs from his wrists. Now, scientists have found a type of spider that does just that.
Like Spider-Man, most spiders can climb sheer surfaces and they do so with two techniques. The most obvious are small claws, called tarsi, that grip onto rough surfaces. Going…
edyong | July 3, 2008Spider silk is a most amazing and versatile material, and spiders put it to all sorts of uses. It helps them to climb, to travel from place to place and most famously, to ensnare their prey. But one group of spiders, the uloborids, use their silk in a unique way - as a murderous garbage-compactor.
Most spiders kill with venom and even those that pose no threat to humans pack enough poison to deal with insect prey. Their famous webs are simply elegant traps, designed to immobilise prey so that the spider can deliver a fatal bite. But the uloborid spiders have uniquely lost their venom…
edyong | June 27, 2008For humans, sight is the most important of senses but only after we are born. Within the womb, surrounded by fluid, muscle and darkness, vision is of limited use and our eyes remain closed. But not all animals are similarly kept in the dark.
Cuttlefish develop inside eggs that are initially stained black with ink, but as the embryo grows and the egg swells, the outer layer slowly becomes transparent. By this time, the developing cuttlefish's eyes are fully formed and we now know that even before they are born, they can use visual information from the outside world to shape their adult…
edyong | June 26, 2008I've written two news stories in this week's New Scientist. One is on the different tactics of four-year-old boys and girls as they compete for animal puppets. The other is on the webs spun by black widow spiders. The article on the venomous, evil, little critters is longer so I'm going to use this space to talk about the black widows instead...
Black widows are notorious for both the toxicity of their venom and the cannibalistic nature of their sex, but their webs are equally interesting and less well known.
The basic design - the "sheet-based" web - consists of a well-defined horizontal…
clock | June 25, 2008Believe it or not, this appears to have something to do with their circadian rhythms!
Back in the 1960s and early 1970s, there was quite a lot of research published on the circadian rhythms in earthworms, mostly by Miriam Bennett. As far as I can tell, nobody's followed up on that work since. I know, from a trusted source, that earthworms will not run in running-wheels, believe it or not! The wheels were modified to contain a groove down the middle (so that the worm can go only in one direction and not off the wheel), the groove was covered with filter paper (to prevent the worm from…
edyong | June 16, 2008Jellyfish may seem like simple blobs of goo, but some are surprisingly sophisticated. The box jellyfish (Tripedelia cystophora), for example, is a fast and active hunter and stalks its prey with the aid of 24 fully functioning eyes. These are grouped into four clusters called rhopalia, which lie on each side of its cube-like body. Together, they give the box jellyfish a complete 360 degree view of its world and make it highly manoeuvrable.
Each eye cluster, four eyes are merely pits containing light-sensitive pigments, but two are remarkably advanced and carry their own lenses, retinas and…
edyong | May 17, 2008As far as humans are concerned, sexually-transmitted infections are things to avoid. But imagine if these infections didn't cause death and disease, but gave you superpowers instead. It may sound like a bizarre fantasy, but it's just part of life for aphids.
Aphids mostly reproduce without sex, giving rise to many all-female generations that are exact copies (clones) of their parents. They only have sex once in autumn, the only time when mothers give birth to males. Asexual reproduction makes sense for aphid mothers since they pass on all of their genes to their daughters. If they…
edyong | May 15, 2008Last year, I blogged about an ironic public health strategy - controlling malaria with mosquitoes. The mozzies in question are genetically engineered to be resistant to the malaria parasite, Plasmodium. The idea is that these GM-mosquitoes would mate with wild ones and spread their resistance genes through the natural population.
The approach seems promising but it relies crucially on the ability of the resistant males to successfully compete for the attentions of females in wild populations. The 1960s and 1970s witnessed several failed attempts to control malaria by swamping natural…
edyong | May 8, 2008
A tenth of the planet's population occasionally suffers through devastating famines because small insects fear being bitten in the bum. That's the astonishing message from a new study of one of mankind's greatest pests - the desert locust.
Swarms can stretch for several hundred square kilometres and each of these harbours up to 80 million hungry sets of mandibles that eat their own body weight in food every day. These plagues are unpredictable but they only form when locust populations reach some sort of critical mass. Desert locusts are two insects for the price of one; at a crowded…