Tuesday, January 26, 2010

Frequency dependent cichlid

The original fequency dependent cichlid fish paper is in Science:
Frequency-Dependent Natural Selection in the Handedness of Scale-Eating Cichlid Fish.

It looks like this common text book story is true. The figure nicely illustrates that having a neat story isn't enough to get your paper into Science but having ten years of data to back it up will do the trick.


Tara said...

There are other spp. of fish that "take bites" out of individuals (would these be termed micropredators then?)

The following paper was mentioned in my parasitology lecture: it seems that one species of fish (the bluestriped fangblenny) is able to take bites from fish at cleaner stations by effectively mimicking the mutualistic cleaner fishes.

Facultative mimicry: cues for colour change and colour accuracy in a coral reef fish (Cheney, 2007)

Mimetic species evolve colours and body patterns to closely resemble poisonous species and thus avoid
predation (Batesian mimicry), or resemble beneficial or harmless species in order to approach and attack
prey (aggressive mimicry). Facultative mimicry, the ability to switch between mimic and non-mimic
colours at will, is uncommon in the animal kingdom, but has been shown in a cephalopod, and recently in a
marine fish, the bluestriped fangblenny Plagiotremus rhinorhynchos, an aggressive mimic of the juvenile
cleaner fish Labroides dimidiatus. Here we demonstrate for the first time that fangblennies adopted mimic
colours in the presence of juvenile cleaner fish; however, this only occurred in smaller individuals. Field
data indicated that when juvenile cleaner fish were abundant, the proportion of mimic to non-mimic
fangblennies was greater, suggesting that fangblennies adopt their mimic disguise depending on the
availability of cleaner fish. Finally, measurements of spectral reflectance suggest that not only do mimic
fangblennies accurately resemble the colour of their cleaner fish models but also mimic other species of fish
that they associate with. This study provides insights into the cues that control this remarkable facultative
mimicry system and qualitatively measures its accuracy.

John Latto said...

Ecologically such species are acting like herbivores. The ecological distinction between a carnivore and a herbivore considers whether they kill their host (herbivore generally no, carnivore generally yes) so rodents that eat seeds and small seedlings are acting ecologically more like carnivores and fish that 'graze' on other fish are behaving more like herbivores.

Fangblenny! What a great name!