Parasites
sporte | August 6, 2008Microbiologist develop some strange habits when it comes to food.
Some take a fatalistic approach. They reason that microbes are everywhere, we're going to die anyway, we might as well eat dirt and make antibodies. You know these people. They quote things like the "10 second rule" when food drops on the floor, tell you we're all getting asthma because we're too obsessed with cleanliness, and let their dogs wash their dishes.
Eeew.
With a few possible exceptions, I'm in the other camp.
I'm the one who freaks out if the cover is left off the salad dressing during dinner. I brush my…
edyong | August 2, 2008
The next time you buy salmon from your local supermarket, think about the hidden costs in each succulent fillet. Compared to wild fish, farmed salmon is far less likely to burden your wallet. But by buying it, you may be placing a much larger burden on the environment. Fish stocks around the world are declining due to over-fishing and 'aquaculture' - the farming of fish - was originally thought to help. But farming brings with it a host of ecological problems.
If the farmed fish are meat-eaters, as salmon are, they must be fed on the proteins and oils of wild fish, which does nothing to…
edyong | July 25, 2008To a science-fiction filmmaker, the concept of being controlled by unseen forces is creative gold, but for the rest of us, it's a fairly unsettling prospect. But like it or not, it's clear that parasites - creatures that live off (and often control) the bodies of others - are an integral part of the world we live in and carry an influence that far exceeds their small size.
Now, a painstaking survey of the residents of river estuaries shows that parasites do indeed punch above their weight, and they aren't slouches in that department either. Despite their tiny size, their combined mass…
edyong | June 24, 2008In 1994, a third of the lions in the Serengeti were killed off by a massive epidemic of canine distemper virus (CDV), an often fatal infection that affects a wide range of carnivorous mammals. Seven years later, a similar epidemic slashed the lion population in the nearby Ngorongoro Crater. While CDV was undoubtedly involved, the scale of the deaths was unprecedented. What was it about the 1994 and 2001 epidemics that claimed so many lives?
Now, a team of scientific detectives led by Linda Munson from the University of California Davis, have solved the mystery. It turns out that the lions'…
edyong | June 5, 2008 On Wednesday, I posted about a parasitic wasp that turns a caterpillar into both a living incubator and a zombie-like bodyguard for its larvae. Well, it seems to be a bumper week for wasp research; today, we have yet another demonstration of the amazing tactics used by these macabre parents to provision their young with food.
The stunning colours of the jewel wasp (Ampulex compressa) belie its gruesome habits. Its grubs feed on the bodies of cockroaches supplied by their mother. When a female wasp finds a roach, she stings it twice - once in its mid-section to immobilise its front legs…
edyong | June 3, 2008Bodyguards have a tough and risky job but they usually get paid for their trouble. But not the caterpillar of the geometer moth. Against its will, it is recruited to defend the developing young of a parasitic wasp, and the only 'reward' it gets for its trouble is to be eaten inside out by the larvae of its attacker.
The vast majority of wasps are "parasitoids", animals that practice the grisly art of body-snatching. They lay their eggs in the bodies of other living animals to provide their newly hatched grubs with a fresh supply of meat. Like HR Giger's alien, the full-grown larvae then…
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 3, 2008I'm away for the weekend so I thought that I'd repost an article from the old Wordpress blog. This is actually the first ever article I wrote for Not Exactly Rocket Science and I've updated it slightly to take more recent findings into account. I'm considering doing these reposts every Saturday, but let me know whether you're keen on the idea.
Cancer cells are, for all intents and purposes, immortal. Having broken free of the rules and strictures that govern other cells, they are free to grow and divide as they please. In a short space of time, a lone cancer cell can form a mass of identical…
edyong | March 16, 2008
Tropical parasitic diseases may lack the headline-grabbing power of bird flu or SARS and they may fail to grab the pharmaceutical industry's attention. But there is no doubt that they are a massive problem. Schistosomiasis, a disease that many people in Western countries will never have heard of, currently afflicts 3% of the world's population, a staggering 20 million people, and almost four times that number are at risk.
Schistosomiasis, also known as bilharzia, affects people living across the tropics. It's caused by parasitic flatworms called blood-flukes, belonging to the genus…
edyong | February 27, 2008
Male insects have a tough time of it. Aside from the usual threats of predators, competitors and the odd hungry female, many are plagued by discriminatory parasites intent on killing them, while leaving their female peers unharmed. These "male-killers" are incredibly successful and infect a wide range of insects, who are themselves a very successful group. One of these killers, a bacteria known as Wolbachia, may well be the world's most successful parasite.
The male-killers are paragons of selfishness. Their success hinges on successfully infecting females, for whithin egg cells, they find…
awild | January 31, 2008
We often think of ants as paragons of hard work, but a surprising number of species get by through mooching off the labor of others. Trachymyrmex fungus growers, the larger spiny ants pictured above, do things the old-fashioned way. They dig their own nests, send workers out to gather food, and meticulously cultivate the fungus garden that serves as the primary food source for the colony.
Then, along comes the slim, sneaky Megalomyrmex symmetochus. These little parasites hollow out a cozy little nest within the Trachymyrmex garden and spend their time leisurely consuming the brood of…
grrlscientist | January 24, 2008tags: researchblogging.org, neotropical ants, Cephalotes atratus, parasitic nematodes, Myrmeconema neotropicum, tetradonematid nematode, evolution, coevolution, fruit mimicry
A neotropical black ant, Cephalotes atratus,
infected with the newly described parasitic nematode,Myrmeconema neotropicum.
The ant's infected and swollen abdomen does not actually take on a red pigment.
It becomes a translucent amber. With the yellowish parasite eggs inside and a touch
of sunlight, it appears bright red.
Image: Steve Yanoviak, University of Arkansas.
In the first known example of a parasite causing…
bleimanb | January 18, 2008Just when Andrew and I decided once and for all that ants couldn't get any more delicious looking, along comes a new parasitic roundworm that turns our whole world on its head! The newly discovered nematode enters the ants when they eat bird droppings and causes their abdomens to resemble ripe, tasty berries. This in turn draws the attention of birds who love both berries and ants. The birds eat the ants, crap out the parasites, and the whole thing starts over again. Now we know what Elton John was talking about in that song in the Lion King!
Seriously though take a look at the picture below…
awild | January 17, 2008
Here's a story about a parasitic nematode that turns black ants into ripe red berries. What's this about?
The parasite needs to get its eggs from an infected ant to healthy ants. Apparently it hasn't been successful the old-fashioned way, just broadcasting its eggs about the environment. Instead, these little worms have figured out a far more effective egg delivery vehicle: birds.
Ants of the genus Cephalotes often feed from bird droppings (for instance, see here). If a parasitic egg can get itself into a bird's digestive system, it'll wind up in a juicy fecal pellet where it may be…