Deep-sea giant squid (Architeuthis) remain one of the ocean’s most charismatic zoological mysteries. While there are plenty of specimens in museums around the world, little is known about their behaviour. Only recently have fleeting glimpses been captured of these creatures in their natural habitat; a 2005 paper (http://rspb.royalsocietypublishing.org/content/272/1581/2583.full) in Proceedings of the Royal Society B described the first ever wild observations of a live giant squid. The author’s photographs showed a huge squid actively hunting at 900m below the surface and they even managed to recover a tentacle that snagged on the bait line (see panels ‘e’ and ‘f’ in the figure).
We also know about the predator-prey interaction between sperm whales and giant squid from the sharp-sucker scars often seen on whale skin and stomach contents (squid beaks are indigestible making them a useful clue to the diet of sperm whales).
Earlier this year, footage taken by a manned submersible was broadcast showing a giant squid 1000m deep in the North Pacific. The footage was captured using near-infrared light (using invisible to humans and squid) since giant squid avoid the bright white light used in conventional filming- perhaps something to do with those enormous eyes? (have a look here: http://www.eeb.yale.edu/ugrad/eeb171pdfs/sa-246-1982.pdf)
See clips from the video at http://www.youtube.com/watch?v=1KN5N1QDaRQ
(picture credit: NHK/NEP/Discovery Channel via Reuters)
As an aside, it’s worth taking a look at this report on the unusual mating behaviour of giant squid – it turns out that male squid giant inject spermatophores directly into wounds that they form on the tentacles of a female:
More recently a somewhat alarming article showed how male squid overcome the challenges of mating at great depths using a ‘super squid sex organ’ – see the long white tubular structure in the picture below.
Definitely a video that will make you laugh! The male red-capped Manakin (Pipra mentalis), a bird found in Costa Rica and Belize (watch out for it if you go there on the Field Course), does a rather cool moonwalk as part of its courtship ritual. It also produces some rather bizarre clicks with its wings. Two YouTube videos show these behaviours:
Researcher describes her work on the Manakin, including excellent high-speed film of how the wing-clicking, concluding with an odd imitation and a rather obvious M Jackson soundtrack.
Better footage, but the English soundtrack has been irritatingly overdubbed in what my ignorant ear thinks is either Russian or Polish. The bird will make you laugh, though.
The advantage of sex, we are told, is that it increases genetic variability and enables organisms to cope with changing environments. There is a rotifer (small freshwater invert) which has done without sex for 80 million years… How do they cope? BBC summary, original article and magazine article in Science (both need you or your institution to have a subscription to get past the abstract).
Seems like a daft question, but the genetic bases of these effects can be quite simple. This article from Science (subscription needed to get past abstract) gives an example from pied flycatchers and shows that the genes are sex-linked. There’s also this summary in the same issue (same rules apply). Thanks to Per Smiseth for this.
Interesting thought piece from BBC journalist Mark Mardell about the contradictory effects of EU policies on the Iberian Lynx. Includes sound of lynx love-making!
A female bonnethead shark (part of the hammerhead family) gave birth to a pup (yes, some sharks are viviparous – this was very important for realising that mammals have eggs. Read my book!). What was interesting is that she had not been in contact with a male – it was a case of parthenogenesis, unusual in such a large animal. Original article in Biological Letters (open access), BBC news item.
Filed under Fish, Oceans, Sex
One of the key areas of evolutionary biology that is crying out for experimental data is sexual selection. This magazine article describes a recent article in Current Biology, which sheds new light on the “lek paradox”. Do male sexual traits (eg peacock “tails”) directly confer a genetic advantage or not? How can they if they are subject to strong sexual selection? In which case, why do females continue to discriminate when they get no genetic benefit?
Filed under Behaviour, Sex
Just the thing for final year students wanting to do some general revision - a Current Biology “primer” article on mate choice. The rest of you should read it, too!
Cool video of Firefly squid coming to shore in Japan in order to lay their eggs. (BBC news, may not work outside UK.)