Dammit Jim!

After a few days touring Beijing and seeing the normal Great, Forbidden and Heavenly sights, I noticed the guidebook mentioned the Peking Man Site in Zhoukoudian as being reasonably nearby. After several days of temples and castles and with the Chinese National Holiday promising to swamp every tourist location in Beijing, I thought it might be nice to take a trip out to see Peking Man’s cave.

To continue in the unintentional theme of bug mating rituals and to see if I can work out how to embed a video here is a cool video of a male jumping spider courting a female:

The sound is half the fun so don’t forget to turn up your speakers. It seems like it must be a part of some research project with the fancy recording set up but I’m not sure who made it. Anyway it seemed pretty cool, so I took a quick look at the literature to see what was going on.

Science Daily ran an interesting summary about researchers verifying the identity of a giant organism found in the Devonian. I’ve always had a soft spot for the Devonian since the rocks in my hometown in Michigan are all from that period so I thought I’d take a look. Even without the childhood memories of brachiopods and trilobites, the Devonian is a pretty cool period in time from about 410 to 360 million years. In the ocean, nautilus-like ammonites flourished while the first bony fish and sharks evolved and radiated. On land, the Devonian started empty with only bacterial and algal mats covering the ground. By the end of the Devonian, forests of ferns and trees populated by insects and other arthropods were flourishing while our tetrapod ancestors took their first steps on to land. Between these two extremes of lush forests and barren ground, an organism whose identity remained unknown for a hundred years after it’s discovery developed and towered over the landscape.

The first scientist, J. W. Dawson, to describe these fossil “logs” (like the picture to the left) thought they were palm tree-like plants and classified them as ancestors of conifers Prototaxites (Taxus is a genus of conifers). When Dawson presented his work in 1870, another scientist attacked it saying that the organism must be a form of giant algae and tried to illegitimately rename the genus. Dawson defended his decision for a while and then silently about-faced, renamed the genus (also illegitimately) and said he had never meant that to imply a relation to conifers. Although there were some suggestions for other classifications, the genus remained largely identified as an algae until 2001 when Hueber published a definitive 36 page paper on the subject.

Spiders males are often cannibalized by their mates after sex. Spiders have two penis-like organs, called pedipalps, which usually break during sex meaning male spiders can only have sex twice. I wasn’t going to write about anymore spider sex but I came across a couple articles about the adaptations that can occur since males with no remaining pedipalps males are evolutionary useless. Often females help their mates find purpose by using the male as dinner. Scientists had thought that this was an example of competition between the sexes with the large female taking advantage of the undersized male (like the picture to the left). Sort of a male spiders are from Mars, female spiders are from Cannibal World Centauri 6. But in 1996 M. C. B. Andrade noticed that males of the redback spider actually perform a difficult somersault maneuver just to position their bodies in prime eating position (her video).

While I am in danger of feeding my reputation as sexually fixated, I did want to put up one more post about weird mating systems before moving onto other non-sexual types of biology. I was taking a quick look at the literature after the post about spider genital breakage and came across an interesting paper on mating in queenless ants (Dinoponera quadriceps). These ants are really interesting in and of themselves and I think I’ll write more about them later. But for now, they have a pretty curious way of mating that manages to one-up the spiders.