Wednesday, October 28, 2009


Hallowe'en this week, and for whatever reason spider science has been making headlines.

For instance, there's a new giant orb-weaver spider from Africa. Orb-weaver spiders are that archetypical spider that most of us think of when we think spiders. They're the ones we see sitting on the webs, that capture insects as they fly by, and are the type we put up as part of our Hallowe'en displays. We have plenty of orb-weaver species here in Canada, but this African one is in a league of its own. First of all, there's the size: the females of this particular species (Nephila komaci) grow to about 10-12 cm across, while the males are 1/5 that size. Can't picture that? It's about the size of the palm of a large man's hand! Then there's the web. Unlike most diaphanous spider webs, this one, over a metre across, is more string like, and is capable of catching small birds. Which the spiders will eat, although they prefer grasshoppers and other insects.

Another spider in the news is the Australian redback. In this case, it's a story of how lazy male spiders can win the mating game. This work comes from the lab of Dr. Maydianne Andrade at the University of Toronto, Scarborough, where they've been studying the mating habits of this relative of the black widow. The interaction of males and females in this species is unique to say the least, it'll be covered in some detail in my book when it comes out in the spring, but for now all you need to know is that the males have to court the females if they want to mate. And it's no short commitment, males have to put in almost 2 hours of attention if they want to mate before they get turned into a meal. Except for this new research, which shows that sometimes males can sneak in and mate without putting in the work, as long as another male has spent the time in courting. The bad news, for the hard worker, is that he doesn't get to mate, he's out-maneuvered by the other male.

And talking of sneaky spiders, earlier this year a spider was discovered making a decoy. By taking refuse and packing it together on the web, it can make a copy of itself to distract predators.

Why so much spider science? Part of it is probably just pure curiosity. But spiders are interesting for another scientific reason. They're a great model for studying evolution and behaviour. Take the male/female size difference. By looking at closely related spiders, we can understand what's driving this evolution in size disparity. The same with behaviour; spiders are a great system for looking at sexual conflict between males and females, and again, sometimes closely related species can behave quite differently, which lets researchers ask interesting questions.

If only they were a little cuter...

Wednesday, October 21, 2009

What's it all about?

Sex anyway.

From a biological perspective, sex is something of a mystery. First of all, it's inefficient. If you want to reproduce sexually, the first thing you need to do is get two individuals, one of each sex, together in the same place. Then, they have to like each other, at least enough to procreate. And, for males, that's the end of the biological role. Sure, humans, and plenty of other species, use males to help protect the offspring, or provide food, or for myriad other reasons. But if those males weren't there using up resources, there could be more females, and potentially twice as many offspring around. More offspring means a greater chance of success for a species.

Which is where researchers have looked for the problems that might be associated with asexuality. By the way, for the purpose of this, I'm going to talk about asexuality in general terms, in fact there are two quite distinct forms, true asexuality, where reproduction is by either fission (like in bacteria) or parthenogensis (where females produce eggs that turn into fully functional organisms), or self-fertilization (where an animal produces both eggs and sperm and is able to fertilize their own gametes).

But back to the problems. The first one is the build up of potentially damaging mutations. This is sometimes referred to as Muller's Ratchet. Basically, the theory is that copying between generations isn't perfect. Each new generation will pick up a few mutations from its parent. That means as time passes, the number of mutations will increase. On its own, each mutation is not a particularly big problem, but if you collect enough, your health is going to suffer, and the species will become less viable. Remember also, that mutations are generally irreversible, so it's not like they are going to fix themselves from one generation to the next. The male then, the theory goes, helps get rid of these mutations by bringing in new genetic information that mixes with the mothers, and hopefully slows the mutation rate.

There's a second theoretical problem that relates to the enviroment. In this problem, you have a species that's wonderfully adapted to where it's living. But then something changes. It might be a new virus that the species hasn't seen before. Or the temperature might start to change. Whatever it is, if you don't have a gene that allows you to adapt, you're in trouble. Males in this case are often the source of the needed genes that either allow resistance or adaptation.

At least those are the theories. What Dr. Patrick Phillips and his team from the University of Oregon wanted to figure out was whether the theories were true or not. In an advanced online publication in Nature Magazine he took C. elegans and manipulated it to turn it into a self-fertilizing hermaphrodite. Sure enough over time, these worms built up mutations, showing the first theory has merit. Then, when challenging the hermaphrodites with a bacterial pathogen, again they were unable to resist infection and disease. In both experiments, controls with hermaphrodites that could outbreed with males did just fine, showing that males do prevent these problems.

So, men can take heart, biologically we do have a function. And of course beyond the basic genetic role, human males, and males of many other species have expanded their role to protection and sharing in the general raising of young. Which is good, we wouldn't want to end up like the Triplewart Seademon. Males of this species are simply a parasitic bag of sperm attached to their female...

Wednesday, October 7, 2009

Nobel Week

My favourite week of the year!

I'm going to do things a little differently in the blog this week. I could describe the winning nobel prizes, but there are plenty of sources for that information. Instead, I'm going to talk about why I think there's still room for the Nobel categories.

There's been some debate this year (as there is every year) about the relevance of the prizes today. There are plenty of fields, important to modern science, that aren't captured in the Nobel's list of possibilities. Environmental research, for instance, is not captured by Medicine, Physics or Chemistry. There's an argument to be made that the categories should be redefined and broadened to recognize fields that didn't exist in the time of Nobel himself.

I'm going to argue against that. Well, not vehemently, because if there were more categories, that would only be a good thing. But when you look at this year's awards, it seems to me that the Nobel committee does pay attention to relevance.

All of these three science awards are for relatively recent work. And in each case, real practical outcomes that affect vast numbers of people, have been achieved. Telomere research has taught us about aging, and cancer and lots of diseases. The CCD and fibre optics have changed communication forever, and we're only scratching the surface of their potential. Ribosomes are a fundamental building block in the cell, and we have a whole class of antibiotics that owe their existence to the understanding of the ribosomal structure. But in all these cases, none of the practicl outcomes would have been possible without the fundamental discoveries of the researchers. In the end, that's what's great about the Nobel prizes. At a time when a lot of research funding is headed to 'applied' research, those who perform basic work can still be gratified to know that their fundamental science will be applauded and recognized by the most famous award of all.

Keep the Nobels, but make more prizes too!