22 September 2011

The SciFund Challenge

I’ve been very pleased that non-scientists have been good enough to support Marmorkrebs.org projects in the past with a bit of their time. The contributions of pet owners have been featured in two papers from my lab to date.

In that spirit, I will be participating in the SciFund Challenge! This is an experiment in social networking and crowdfunding. In November and December, participating scientists will try to raise a small amount of money for a research project. This will be conducted in association with Rockethub.

I will have more details as we get closer to the official launch of the project. In the meantime, check out the SciFund blog for more news and explanations for the rationale behind this project.


Faulkes Z. 2010. The spread of the parthenogenetic marbled crayfish, Marmorkrebs (Procambarus sp.), in the North American pet trade. Aquatic Invasions 5(4): 447-450. http://dx.doi.org/10.3391/ai.2010.5.4.16

Jimenez SA, Faulkes Z. 2010. Establishment and care of a laboratory colony of parthenogenetic marbled crayfish, Marmorkrebs. Invertebrate Rearing 1(1): 10-18. http://inverts.info/content/establishment-and-care-laboratory-colony-parthenogenetic-marbled-crayfish-marmorkrebs

16 September 2011

Being a fish out of water

It might be tricky to keep mangrove rivulus in your typical aquarium. Mangrove rivulus are rather found of jumping out of water – and staying there.

Being out of water is a rather different place from being in the water, and so this fish obviously have some evolutionary adaptations that allow it to pull off this stunt. But a new paper asks a different, possibly more subtle: do mangrove rivulus adapt to being in or out of water in the short term?

ResearchBlogging.orgMangrove rivulus have an advantage for studying these sorts of short-term physiological changes, as many of them are genetically identical, because they are hermaphrodites - not all that unusual among animals, but that they are self-fertilizing hermaphrodites is a rare and exceptional feature among vertebrates.

Turko and colleagues first did a simple correlative study, allowing the fish to jump out of their tanks as often as they want. Most stayed in the water most  of the time, but a few appeared to have what would have been a death wish in most other fish: they were out of the water almost two thirds of the time (64%). The authors saw differences in the gill shape that were correlated with the amount of time fish spent in or out of water.

But because correlation does not mean causation, the authors sensibly went back and did an experiment. They monitored animals for a week, then prevented them all from leaving the water, sacrificed half to check on their gills, and then left the remaining half go back to being free to leave the water if they chose.

The first that were prevented from leaving the water had different gill shapes than those that were allowed to return to the air. This strong suggests that the fishes’ behaviour drove the changes in the gill morphology.

But there is a problem in interpretation here. At the start of the second experiment, the fish were leaving water rather less than in the first correlation study. And there were no correlations between gill shape and the fish’s behaviour after the first week, as there was in the first study. The differences in gill shape emerged only after the week were the fish were forced to stay within water. The researchers suggest that there may be a minimum time the fish have to spend out of water for the gill remodeling effect to occur.

This makes me wonder if there were be a way to do the experiment were fish were forced to stay out of water for set periods of time. Here, the experimenters were at the mercy of the fish voluntarily leaving the water. It may be a little bit trickier, but the results would be much easier to interpret.

Related posts

Conquest of the land, a la Chubby Checker (on NeuroDojo)
Celebrate diversity: The fish that fertilizes itself


Turko A, Earley R, Wright P. 2011. Behaviour drives morphology: voluntary emersion patterns shape gill structure in genetically identical mangrove rivulus. Animal Behaviour 82(1): 39-47. DOI: 10.1016/j.anbehav.2011.03.001

06 September 2011

Molting in a nightclub

AT least, molting in a nightclub is the best explanation I have at hand for the soundtrack on this video.