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Chemical communication in mating shore crabs Carcinus maenas

Ekerholm, Mattias LU (2005)
Abstract (Swedish)
Popular Abstract in Swedish

Att kunna lokalisera och bedöma en partner är en av de, evolutionärt sett, viktigaste egenskaperna hos alla sexuellt reproducerande organismer. För att möjliggöra detta använder sig ett djur sig av olika (visuella, taktila, akustiska och kemiska) signaler för inomartskommunikation.



Jag har genom att studera kemiska signaler för inomartskommunikation (s.k. feromoner) hos strandkrabban Carcinus maenas kommit fram till att ämnen från motsatta könet kan spela stor roll för den naturliga sekvensen av parningsbeteenden, från sökande till parbildning. För att visa på detta har jag undersökt feromonresponser till motsatta könet hos både hanar och honor i tre rumsliga... (More)
Popular Abstract in Swedish

Att kunna lokalisera och bedöma en partner är en av de, evolutionärt sett, viktigaste egenskaperna hos alla sexuellt reproducerande organismer. För att möjliggöra detta använder sig ett djur sig av olika (visuella, taktila, akustiska och kemiska) signaler för inomartskommunikation.



Jag har genom att studera kemiska signaler för inomartskommunikation (s.k. feromoner) hos strandkrabban Carcinus maenas kommit fram till att ämnen från motsatta könet kan spela stor roll för den naturliga sekvensen av parningsbeteenden, från sökande till parbildning. För att visa på detta har jag undersökt feromonresponser till motsatta könet hos både hanar och honor i tre rumsliga kontexter.



Hanar söker efter källan till honferomoner, och beroende på feromonkoncentration och avstånd så blir responsen en allt högre grad av parningsrelaterade beteenden.



Responserna till honurin varierar mycket, och påverkas dels av ett primerferomon i honans urin och dels av honans ömsningsstatus och hanens status.



Honferomonet har beroende på bristande långdistansegenskaper dock inte kunnat förklara hur hanar attraheras på distans till honor, befintliga bevis visade snarare på motsatsen, att honor söker efter hanar. Honor I rätt ömsningsstadie söker upp hanar över långa avstånd. Honorna kan skilja på han och hondoft och att de faktiskt visar på ökad sökaktivitet, riktad mot handofter, medan hondofter inte utlöser detta sökande. Precis som hos honan finns feromonet i hanens urin, och vid höga urinkoncentrationer så visar honan upp parbildningsspecifika beteenden på liknande sätt som hanen gör till honferomonet. Honorna kan också skilja på, och föredrar att söka sig till dominanta hanars doft. Honorna drogs även i högre grad till dominanta hanarna de hade sett fightas tidigare än till obekanta dominanter.



Jag har genom min avhandling visat på hur kemisk kommunikation under parningen är av avgörande betydelse för en marin art, i detta fall strandkrabban. Resultaten visade också på ett feromonkommunikationssystem intimt knutet till parningsstrategin (lek), och att fullständiga stereotypa beteenden i anslutning till parningen kan utlösas av doftstimuli från det motsatta könet. (Less)
Abstract
Locating and evaluating a suitable partner for mating is one of the most important events in any sexually reproducing organism. To achieve this, an animal must be able to locate its partner over both long and short distances, and finally evoke the proper mating behaviour. This is made possible by use of conspecific signals picked up by one or several sensory systems, the most well investigated being visual, acoustic, tactile and olfactory.



This thesis presents evidence that the shore crab Carcinus maenas utilize pheromones and other chemical signals for mating. Briefly, I have studied male and female responses to odours and urine from both sexes in long-range, near-range and at contact range.



Males are... (More)
Locating and evaluating a suitable partner for mating is one of the most important events in any sexually reproducing organism. To achieve this, an animal must be able to locate its partner over both long and short distances, and finally evoke the proper mating behaviour. This is made possible by use of conspecific signals picked up by one or several sensory systems, the most well investigated being visual, acoustic, tactile and olfactory.



This thesis presents evidence that the shore crab Carcinus maenas utilize pheromones and other chemical signals for mating. Briefly, I have studied male and female responses to odours and urine from both sexes in long-range, near-range and at contact range.



Males are attracted to female urine pheromones. When concentration and spatial scale are varied, the same chemicals (urine) evoke a chain of different behaviours. At close distance and high concentrations pairing-related behaviours are evoked, and search-related behaviours and display are abandoned. Conversely, low concentrations on longer distances show more search and display and no pairing behaviour.



Response variability plays a significant role in modifying behaviour in this species. I have shown that much of this can be attributed to a novel primer pheromone, which increases male receptivity to the female pheromone. Female moult stage also affects male responses at contact-range, but not at near-range. Male status also affect his search, but not pairing behaviour.



The female pheromone has due to the lack of long-range properties not been able to explain how males locate females over a distance. Instead, present evidence suggested that the pattern may be reversed, with females of the right moult stage locateing males over long distances. The females are able to discriminate between male and female odour and search preferentially for males. The pheromone in male urine evokes several pairing-specific behaviours in females, similar to the case of males and female pheromones.



As a final step in linking pheromone communication to the lek mating system, we show that females are able to identify male status by odour, and preferentially search for the dominant male. Females previously exposed to a fight between the dominant and subordinate male also showed higher preference for the dominant, than females that were unfamiliar with the males.



This dissertation shows that chemical communication during the mating period is of utmost significance for a marine species, the shore crab. Apart from this I have shown that complex behavioural chains can be evoked by the same cue, presented at different spatial context and concentration. I have also shown how important it is to know the mating system of the species to be able to identify the steps where pheromones and other chemical signals affect behaviour such as search and choice of a partner. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Dr Breithaupt, Thomas, Univeristy of Hull, Hull, UK
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Zoology, Urine communication, Behavior, Spatial scale, Male pheromone, Primer pheromone, Zoologi, Olfaction
pages
100 pages
publisher
Department of Cell and Organism Biology, Lund University
defense location
Zoology building, Helgonavägen 3 223 62 Lund
defense date
2005-09-29 10:00
ISBN
91-85067-19-9
language
English
LU publication?
yes
id
66e247eb-c51b-4806-9bd9-ba589baefe16 (old id 545343)
date added to LUP
2007-09-04 11:03:26
date last changed
2016-09-19 08:45:10
@phdthesis{66e247eb-c51b-4806-9bd9-ba589baefe16,
  abstract     = {Locating and evaluating a suitable partner for mating is one of the most important events in any sexually reproducing organism. To achieve this, an animal must be able to locate its partner over both long and short distances, and finally evoke the proper mating behaviour. This is made possible by use of conspecific signals picked up by one or several sensory systems, the most well investigated being visual, acoustic, tactile and olfactory.<br/><br>
<br/><br>
This thesis presents evidence that the shore crab Carcinus maenas utilize pheromones and other chemical signals for mating. Briefly, I have studied male and female responses to odours and urine from both sexes in long-range, near-range and at contact range.<br/><br>
<br/><br>
Males are attracted to female urine pheromones. When concentration and spatial scale are varied, the same chemicals (urine) evoke a chain of different behaviours. At close distance and high concentrations pairing-related behaviours are evoked, and search-related behaviours and display are abandoned. Conversely, low concentrations on longer distances show more search and display and no pairing behaviour.<br/><br>
<br/><br>
Response variability plays a significant role in modifying behaviour in this species. I have shown that much of this can be attributed to a novel primer pheromone, which increases male receptivity to the female pheromone. Female moult stage also affects male responses at contact-range, but not at near-range. Male status also affect his search, but not pairing behaviour.<br/><br>
<br/><br>
The female pheromone has due to the lack of long-range properties not been able to explain how males locate females over a distance. Instead, present evidence suggested that the pattern may be reversed, with females of the right moult stage locateing males over long distances. The females are able to discriminate between male and female odour and search preferentially for males. The pheromone in male urine evokes several pairing-specific behaviours in females, similar to the case of males and female pheromones.<br/><br>
<br/><br>
As a final step in linking pheromone communication to the lek mating system, we show that females are able to identify male status by odour, and preferentially search for the dominant male. Females previously exposed to a fight between the dominant and subordinate male also showed higher preference for the dominant, than females that were unfamiliar with the males.<br/><br>
<br/><br>
This dissertation shows that chemical communication during the mating period is of utmost significance for a marine species, the shore crab. Apart from this I have shown that complex behavioural chains can be evoked by the same cue, presented at different spatial context and concentration. I have also shown how important it is to know the mating system of the species to be able to identify the steps where pheromones and other chemical signals affect behaviour such as search and choice of a partner.},
  author       = {Ekerholm, Mattias},
  isbn         = {91-85067-19-9},
  keyword      = {Zoology,Urine communication,Behavior,Spatial scale,Male pheromone,Primer pheromone,Zoologi,Olfaction},
  language     = {eng},
  pages        = {100},
  publisher    = {Department of Cell and Organism Biology, Lund University},
  school       = {Lund University},
  title        = {Chemical communication in mating shore crabs Carcinus maenas},
  year         = {2005},
}