Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Bizarre reproductive techniques discovered for deep-ocean squid

10.12.2008
Males that produce sperm packages that can penetrate deep into the skin. Females with bellies full of stored sperm. Males that seriously injure the females during mating.

This is just a selection of the bizarre reproductive techniques that marine biologist Henk-Jan Hoving has discovered with different species of deep-ocean squid. He will be awarded a PhD by the University of Groningen (Netherlands) on 19 December 2008.

‘Reproducing in the deep ocean is a real challenge’, says Hoving. The deep ocean is unbelievably huge – 80 percent of the seafloor lies at depths of two kilometres or more. It’s not easy to find a partner in that gigantic, pitch-black environment. So, once you find one, you have to seize the moment. Squids that live in the deep ocean have developed a wide range of fascinating reproductive techniques to this end.

Deep cuts

Hoving investigated the reproductive techniques of no fewer than ten different squids and related cuttlefish – from the twelve-metre long giant squid to a mini-squid of no more than twenty-five millimetres in length. Along the way he made a number of remarkable discoveries. Hoving: ‘Reproduction is no fun if you’re a squid. With one species, the Taningia danae, I discovered that the males give the females cuts of at least 5 centimetres deep in their necks with their beaks or hooks – they don’t have suction pads. They then insert their packets of sperm, also called spermatophores, into the cuts.’

Through the skin

With a different species, the Moroteuthis ingens, the spermatophores are introduced in a more peaceful way. ‘With this species the spermatophores penetrate the skin independently. They probably do that with the help of an enzyme-like substance that dissolves tissue.’ Hoving is the first to be able to prove that these sperm packets are able to penetrate the skin under their own steam. He discovered this when he experimentally placed spermatophores on the skin of just-caught individuals. His results are supported by an incident in Japan, where someone had to have an operation after eating squid to remove a spermatophore that lodged in his throat.

Sperm in reserve

When studying the mini-squid Heteroteuthis dispar, Hoving also made an extraordinary discovery. For the first time he found a squid that probably fertilizes its eggs internally. ‘The females have a pouch for storing sperm that is directly linked to the belly and the oviducts. This indicates that fertilization takes place within the body and not outside - which is more common for squid.’ Males fill the female’s pouch with a great deal of sperm. About three percent of the body weight of a female who has mated consists of stored sperm. This has a number of advantages. The females, who produce eggs over a long period, thus have a steady supply ‘in reserve’ which they can make use of. Another advantage is that when the pouch is full, no sperm from other males will fit.

Female characteristics

Hoving was also the first to discover male squid with female characteristics. ‘Usually, squid have separate sexes. There are no hermaphrodites, as with snails. But with one species, Ancistrocheirus lesueurii, some of the males turned out to have small glands that in females are involved in egg production. They also had significantly longer bodies than “normal” males.’ Hoving cannot explain this phenomenon. ‘It’s possible that it’s the result of hormones and hormone-like substances that end up in the surface water as a result of human action – for example use of the pill – and then sink down to the deep ocean. However, it may also be an alternative reproductive strategy and a way of getting closer to the females.’

Vulnerable ecosystem

Hoving’s research has produced a wealth of information about deep-ocean squid. ‘Previously, there was little known about these organisms. That was because they were very difficult to study. The deep ocean is very inaccessible. Diving to such depths is only possible with the help of advanced technology.’ In order to gain an understanding of the reproductive habits of squid he had to use dead individuals, which he got hold of in many inventive ways. ‘For example, I’ve joined scientific expeditions but have also used examples that were found in the 1960s and 1970s in the stomachs of commercially caught sperm whales.’ Hoving hopes that his research will contribute to sustainable exploitation of the deep ocean. ‘Fishing is taking place at deeper and deeper depths. The deep ocean is a very vulnerable ecosystem, however. We desperately need to learn more about this ecosystem.’

Jos Speekman | alfa
Further information:
http://www.rug.nl

More articles from Life Sciences:

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>