Exploiding yourself for the good of your kin

Image taken from http://www.myrmecos.net/insects/ManzAphid3.html

It's been quiet for a while. Not because any lack of cool things to write about; just because a general gloomy period with lots of work and a home computer not willing to cooperate.

But now I'm back. At least for a post. Better one post in the blog than ten in the head, we might say. Well, you perhaps have noticed that I like insects. And you perhaps know that I like a touch of the weird and morbid. So of couse I just had to write something about this: apids exploding themselves for safety of the community in a manner that would make 2nd-WW-kamikaze-soldiers and al quaida green with envy.

These aphids life in so called galls, a ball-like plant tissue that has been induced by the aphids. Then they prefer to live a cosy, non-disturbed life in there, which of course is not always the case. A lot of things could threat their existance, so therefore it's been necessary to evolve an efficient defence system using community members with an explicit role - the soldiers.

So when the gall is damaged, the soldiers aggregate around the area and explode (!), which results in the formation of a sealing goo that protects the gall.

Beats building a ugly wall and shooting at every moving object passing it.

200 year anniversary!

Happy birthday Mr Darwin!

Snikes!

I suppose you haven't missed out on the news about a gigantic snake snirling around this globe for a couple of million years ago?

This fella (baptized as Titanoboa cerrejonensis) was around 13 m long (larger than the snake trying to eat Jennifer Lopez in the lame movie Anaconda, according to the researcher), and it's assumed that there's been even larger ones crawling on the surface of the earth we now walk...now that is something I'd gladly live a life without ever coming across.

Source:

http://blogs.nature.com/news/thegreatbeyond/2009/02/giant_snake_eats_worlds_media.html

http://www.nature.com/news/2009/090204/full/news.2009.80.html

Worm up your life!

This is more horrific than any scary movie ever.

Ressurection

What's been seen as a combination of dreams and science fiction has been accomplished: an extinct (sub)species, The Pyrenean ibex (Capra pyrenaica pyrenaica), has been brought back into the world of the living. I can't wait for the ressurection of the Dodo...or the mammut!

Source:
http://www.newscientist.com/blogs/shortsharpscience/2009/02/first-animal-to-be-cloned-back.html

Separated by germs

There's a group of parasitiod Hymenopteras called The Jewel Wasps, Nansonia. They like to lay there eggs in or on other insects, where the larvae will exploit their host's nutrients, which in the end leads to the host's death. I've written about similar systems before.

What I haven't written about (because I didn't know it until now) is the very facinating background of how three species, N, vitripennis, N. giraulti and N. longicornis, are reproductively isolated in nature (they can't produce any offspring, basically). Usually, reproductive isolation is a result of the genetic conflicts of the gametes (egg and spermcells), making embryonic development impossible or severely harder. Or, as in moths, reproductive isolation is the result of the species using different chemicals (pheromones!) to find eachother for mating. There are many more quite easy-to-comprehend examples of the beckground to reproductive isolation. But now I've found this information about the three Nansonia species.

Some more background is needed though, before I get to the basis of what I'd like to say: in some insects, a certain type of bacteria has somewhere along the evolutionary line managed to infect and stay put in the insects cells. The bacterium, known as Wolbachia, has then gradually evolved in sync with the insect so that it becomes kind of symbiont (endosymbiosis - a phenomenon that has led to the mitochondria found in plant, fungi and animal cells, as well as the chloroplasts in plant cells). The different insect species therefore have different variations of Wolbachia. Well, it turns out that in the three Nansonia species, it's their species specific Wolbachia that causes reproductive isolation. Because if the Wolbachia is removed (using antibiotics) the species are suddenly able to breed and produce fertile offspring. I don't know about you but for me this is SO cool. Yes, I'm odd.

Source:
Genome Mapping and Genomics in Animals, Volume 1
Wayne Hunter, Chittaranjan Kole (Editors)
Genome Mapping and Genomics in Arthropods
C H A P T E R 3
The Jewel Wasp – Nasonia
Jürgen Gadau, Oliver Niehuis, Aitana Peire, John H. Werren, Emmanuelle Baudry, and Leo W. Beukeboom

Itsy bitsy spider

Image taken from http://scienceblogs.com/pharyngula/2006/03/spider_kama_sutra.php

Living in a more or less religion-influenced society, it's easy to judge our culture as becoming more and more obsessed in things regarding mating. Girls show off bums and hill-look-a-like body parts, boys try to excell by showing off how good of a catch that they are, commersials try to sell just about everything by giving it a touch of mating-indications. This may be percieved as vulgar and cheap to many of us, but in the spotlight of evolution it's really a good concept because this will pass on genes for ever and ever (although they will be changed over time).

As I've mentioned before, there's plenty of variation among mating systems, and everything seems to be allowed as long as it yields offspring of reproductive value. The spider Homalonychus theologus for example, has a thing for bondage, which might be a word of perverse indications to some of us. This does not become H. theologus, who's life is dictated by other matters than morals and family values. When the male approaches a female, he wraps her legs in silk before proceeding with mating. This behaviour can be found in other spiders as well (Xysticus, Tibellus, Latrodectus, Dictyna, Oxyopes and Nephila maculata).

Basically, it's quite "easy" to come up with theories to why "weird" mating systems arise:
1. We have a group of interbreeding individuals.
2. In one of the individuals, a mutation (or mutations) is induced in it's gametes (sperm and egg cells).
3. The resulting offspring bearing this mutations has a deviation from the original mating system due to this.
4. The mating deviation causes this individual to be able to mate more, mate more succesfully, or mate in any other way that will increase it's ability to produce offspring.
5. The offspring (or atleast some of them, depending on the nature of the mutation) will inherit it's parent mating system deviation and thus have a reproductive advantage to the individuals without the mutation.
6. Over time (without taking other evolutionary factors in regard, such as genetic drift) this mutation will increase in frequency and become normal.

Since humans are cultural beings, it's not very easy or wise to try to explain all our "deviation" with genetics. But the fact that sex sells is very easy, because liking to reproduce (sex) generally means (in a world without contraceptives....as in 50 years ago and backwards in time) a lot of kids, which means a lot of kids growing up to liking to reproduce and so forth. So don't blame our world todaty, if you don't like what you see; blame our ancestors. But then, if they'd listened to your possible arguments, you may not have been born. Ever.


(Of course it's good to question everything, especially the media and fields out to exploit your wallet, but questioning everything ad absurdum will not lead us anywhere than to supression of innate behavioural factors).

Source: http://www.bioone.org/perlserv/?request=get-abstract&doi=10.1636%2FM03-4&ct=1