Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Biologist Discovers What May Be World’s ’Pickiest’ Mates

03.08.2005


Photo of male California fiddler crab
Credit: Catherine deRivera


California fiddler crabs may be among the world’s pickiest animal when it comes to selecting a mate.

A study conducted by a biologist at the University of California, San Diego that appears in the August issue of the journal Animal Behaviour found that females of the species Uca crenulata may check out 100 or more male fiddler crabs and their burrows before finally deciding on a mate.

“As far as I know, no other species has been observed sampling nearly as many candidates as the California fiddler crab,” said Catherine deRivera, who conducted the study while a doctoral student and a lecturer at UCSD. She is now a research biologist at the Aquatic Bioinvasions Research and Policy Institute, a joint entity of the Smithsonian Environmental Research Center and Portland State University.



deRivera and a group of UCSD students who assisted her conducted their observations in the Sweetwater River estuary in Chula Vista, south of San Diego, near the Mexico-U.S. border. She said previous studies of mate selection in other animals, such as birds and the natterjack toad, found that females of most species typically sampled only a handful of potential mates before making a final selection.

“Most animals sample just a few mates, presumably because search costs override the benefits of lengthy searches,” she said in her paper. But female California fiddler crabs are much pickier, she discovered in her study, checking out male suitors and their bachelor pads an average of 23 times before making a final selection. One particularly choosy crab visited 106 male burrows, fully entering 15 of them, during her one hour and six minute search.

Why are female fiddler crabs so picky? The survival of their offspring, deRivera found in her experiments, appears to be strongly linked to the size of their mate and, more importantly, his corresponding abode.

“The size of the male’s burrow affects the development time of his larvae,” she said. “A burrow of just the right size allows larvae to hatch at the safest time, the peak outward nighttime flow of the biweekly tidal cycle.”

“Wide burrows speed incubation, so they cause the larvae to hatch too early and miss the peak tides. This research provides one of the first examples of how choosy resource selection can help offspring survivorship.”

Male fiddler crabs attract suitors by standing in front of their burrows and waving their enlarged claws at prospective female passers by, much as humans motions “come here” with their arms and hands

“The California fiddler crabs use a lateral wave that looks much like a human beckoning ’come here’,” deRivera said. “It also seems to serve as a ’come hither’ signal, as a male waves, standing at his burrow entrance, and interested females come over.”

Interested females initially eye the males, who select their burrows based upon their body size, and if they’re interested, partially or fully enter a burrow to size it up.

“The burrow openings, which are circular, are just big enough for the owners to get in,” deRivera said. “Crabs enter burrows sideways so have to fit in front to back and top to bottom.”

When a female has found a mate and burrow to her liking, typically one that is about the same size as she, either she or the male will plug up the opening of the burrow and the couple will mate and incubate their eggs, which later hatch and release tiny crab larvae that are quickly flushed from the estuary by high night tides.

deRivera found that larger female crabs couldn’t be as picky about choosing mates as their smaller counterparts. They took less time, she noted, because they entered fewer burrows, primarily because many of the burrows they passed were too small to accommodate them and successfully incubate their eggs and release their larvae.

“Larvae were successfully released during high-amplitude nocturnal tides only when females incubated in burrows that allowed the larvae to exit the estuary swiftly and thus reduce predation risk, but not when females incubated in burrows that were too wide or narrow,” deRivera writes in her paper. “The effect of burrow aperture on incubation duration may explain why females sampled many male burrows as they searched for a mate and why females of different size classes selected and sampled differently.”

Comment: Catherine deRivera (503) 725-9798, derivera@pdx.edu, derivera@si.edu
Media Contact: Kim McDonald (858) 534-7572

Catherine deRivera | EurekAlert!
Further information:
http://www.ucsd.edu

More articles from Life Sciences:

nachricht Toward a 'smart' patch that automatically delivers insulin when needed
18.01.2017 | American Chemical Society

nachricht 127 at one blow...
18.01.2017 | Stiftung Zoologisches Forschungsmuseum Alexander Koenig, Leibniz-Institut für Biodiversität der Tiere

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

A big nano boost for solar cells

18.01.2017 | Power and Electrical Engineering

Glass's off-kilter harmonies

18.01.2017 | Materials Sciences

Toward a 'smart' patch that automatically delivers insulin when needed

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>