Fantail Darter: Etheostoma flabellare


The spawning begins in the spring with a male finding a suitable 'nest'. This usually in shallow water under flat rocks (Knapp, Roland A., and Robert Craig Sargent 1989). Once he finds a spot suitable he waits for a female.  There are a couple observed traits males display that makes them more desirable to females. Larger males are more likely to mate than their smaller counter parts. The larger size makes the male more advantageous when it comes to defending the nest (Moretz, Jason A., and William Rogers 2004). Females also prefer males that already have eggs. The fantail darter is a species where the male tends the eggs, so when a females sees a male already with eggs she deems him an appropriate protector for future young as well. This has caused males to evolve egg-mimicry strategies. Many now have structures that looks like eggs attached to the dorsal fin. While this has been seen in both sexes, the egg-mimicry is much larger and more developed among the males versus the females (Knapp, Roland A., and Robert Craig Sargent 1989).        

When a female then chooses a male she will deposit her eggs in the nesting area, one or two at a time, and attach them to the underside of a rock. This can total to between nine to twenty-four eggs. After she is done the male will release his sperm over the eggs to fertilize them. While this is happening both sexes exhibit a color change in parts of their bodies where the lower fins and regions of the head turn black (Moretz, Jason A., and William Rogers 2004).

Throughout this process there usually are multiple behaviors observed. The most common behavior is during the courtship either is sex will start to quiver in place. There are several hypotheses as to what this quivering signals or is brought on by. One is that the female does it to help entice the male and encourage him to fertilize eggs, and the male quivers for the female to release her eggs. Another possibility could be that it is caused by the release of gametes. The second most seen behavior is both sexes will have a rest period where both will lie on the river bottom facing each other in no particular way. It also is very common for both the male and female to lay directly next to one another with their heads facing the opposite way (Moretz, Jason A., and William Rogers 2004).

Once the eggs are fertilized it will take a little less than 35 days for them to hatch. During this time the male will watch over them and often resort to filial cannibalism. It is more common among smaller amounts of eggs that the male will eat all of them, and males with more eggs are more likely to consume only part of their offspring. This is thought to be done so that the male can gain nutrients that he cannot find elsewhere (Lindstrom K., and R. C. Sargent 1997).



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