Female crabs ‘offer sexual favours in exchange for protection’
November 4th, 2009 - 1:52 pm ICT by ANIMelbourne, Nov 4 (ANI): An Australian study has found that female fiddler crabs have sex with their male neighbours in exchange for protection against wandering male intruders.
Both male and female fiddler crabs shelter in burrows which they both must defend from intruders.
But while males have an extremely large claw that can be used as a weapon, female crabs have just two small feeding claws.
So to show female crabs defend their territory, lead author Patricia Backwell from the Australian National University and colleagues based their new study on previous work that showed that under certain circumstances, males would help protect a neighbouring male from an intruder.
In the new study, the researchers found that males will also defend neighbouring females - apparently in return for sex.
The researchers first established the background mating rate of Uca annulipes fiddler crabs on mudflats in Durban Harbour, South Africa.
They found that most of the time females mate with a carefully chosen mate in his burrow but sometimes they are willing to mate with other neighbouring male, on the surface of the mudflat.
Co-author Michael Jennions said that given how fussy females normally are with their mate choice, there must be some benefit they get out of mating with the average male neighbour.
The researchers set a number of trials in mudflats in Mozambique to study whether a male would protect a female neighbour when confronted by an intruder.
They super-glued a tether to the shell of a crab, placing it near the entrance of a female burrow to simulate an intruder.
When the intruder was male a neighbouring male rushed in to defend the female 95 percent of the time, but when the intruder was female protection only occurred 15 percent of the time.
Jennions says it makes sense for a male crab to defend a female neighbour.
“Females are a weak neighbour and it’s good to have a weak neighbour. In addition, you have the added bonus that as a male that you can mate with a neighbour if she’s a female,” ABC Online quoted Jennions as saying.
The findings have been reported in the Royal Society journal Biology Letters. (ANI)
- Crabs spy on competitors to detect female mates - Jun 02, 2010
- Shrimps 'rumble' to keep predators at bay - Sep 09, 2011
- Fiddler crabs build chimneys around their burrows to keep intruders out - Oct 13, 2008
- Chivalrous male cricket would die for his female - Oct 07, 2011
- Scientists find female frogs call out during sex to excite lover - Apr 30, 2011
- Genes drive gender specific behaviours in parenting, sex - Feb 03, 2012
- Male crabs bluff to scare rivals away - Nov 17, 2008
- Sex and aggression linked in the brain - Feb 10, 2011
- Alert crabs outwit predatory birds - Apr 19, 2011
- How lying saves crabs lives - Nov 12, 2008
- Male wolf spiders 'mate with virgins and cannibalise older females' - Apr 13, 2011
- Catching crabs with shark fins and chicken guts in rural Goa - Jan 05, 2011
- Inflatable Female Toads Are Very Selective About Who They Mate With - Jul 09, 2010
- 40-million-year-old mating mites reveal sex role reversal - Mar 01, 2011
- Female mites dominated males in sex: Experts - Mar 17, 2011
Tags: author michael, backwell, bonu, burrow, burrows, co author, colleagues, durban harbour, fiddler crabs, intruder, intruders, male crab, mate choice, mozambique, mudflat, mudflats, neighbours, sexual favours, tether, time females