Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Lovesick Crab Hot on the Odour Trail

21.10.2005


Stimulated by a female pheromone, a crab male will grasp a female and carry her, thus protecting her during the period around her moulting. Mating is possible only during a short time after the moult.


With the antennae to the ground, the female shore crab hunts for prince charming. The olfactory organs are contained within the antennae of crabs. To the shore crab, odours and tastes form the letters of the language of love. The role of chemical communication in the love life of shore crabs has been charted in a new dissertation from Lund University in Sweden.

Mattias Ekerholm at the department of Cell and Organism Biology, Lund University in Sweden has studied the role of odours in shore crab mating. The female needs to find a male quickly, since she can only mate during a brief period directly after shedding her old shell ( i.e. moulting). She sniffs her way to a group of males competing for dominance. Following the scent trail of a dominant male, she also tries to avoid other males. Once near the male, she is overwhelmed by his odour, and rises up on tip-toe at the same time as she pumps her urine towards him. The female urine contains a pheromone that immediately makes the male respond. Mattias describes mating the following way:

- Now the male also starts walking around on tip-toe. With claws extended, he tries to look as impressive as possible. He has picked up the scent of the female. He then sniffs and tastes his way along her scent trail and, after a while he manages to find her.



- They circle around each other for a while, suddenly he rushes towards her and tries to grab and carry her beneath him. She first resists him to assess his quality. If he manages to hold her, she eventually stops resisting. He has passed the test and won the female.

The male then carries the female beneath him for between a few days to over a week. During this time, mating and insemination take place. To ensure that the male does not let her go while moulting - when she is most vulnerable - she releases another odour that reinforces the male’s determination to carry her.

Recently, the shore crab has become more common along the Swedish west coast. This is thought to be either due to decreased predation from cod, or increased abundance of filamentous green algae, the settling substrate of the larvae.

Unintentionally, the shore crab has been introduced to other parts of the world. In Canada, USA (where it is known as the green crab), and Australia, it is perceived as a pest species, where it eats or outcompetes native fauna, and damages aquaculture. Sexual pheromones, that is, chemical substances utilized for between-sex communication may be useful to manage these populations. This technique has been successfully applied to insect pest management.

- We still know very little about pheromones in marine animals compared to those used by insects. But in five years, there may be a reliable and effective means of utilizing pheromones in pest management. In that case I think it is better to direct interest to the male pheromone than the female, since it works to attract females over long distances. If you want to reduce the population, it is also more effective to trap the females, Mattias Ekerholm says.

Göran Frankel | alfa

More articles from Ecology, The Environment and Conservation:

nachricht A new indicator for marine ecosystem changes: the diatom/dinoflagellate index
21.08.2017 | Leibniz-Institut für Ostseeforschung Warnemünde

nachricht Value from wastewater
16.08.2017 | Hochschule Landshut

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Cholesterol-lowering drugs may fight infectious disease

22.08.2017 | Health and Medicine

Meter-sized single-crystal graphene growth becomes possible

22.08.2017 | Materials Sciences

Repairing damaged hearts with self-healing heart cells

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>