Species recognition and hybridization in four Carribbean Damselfish (Stegastes)

This study is designed to test whether species that form hybrids are more likely to treat each other as conspecifics than species that typically do not interbreed. In Jamaica, we know that the dusky damselfish (Stegastes adustus) and the longfin damselfish (S. diencaeous) have formed hybrids while the two other closely related species, the beaugregory (S. lecostictus) and the three-spot (S. planifrons) do not. Interestingly, the formation of hybrids between the longfin and the dusky appears to be island specific. That is, we recorded no hybrids in Barbados.

 

Using both Jamaica and Barbados, we will use behavioral and genetic tests to determine whether the presence or absence of hybrids can be related to species recognition and whether this recognition is related to a specific location. We have devised a simple series of behavioral tests that have been shown to be useful in testing the ability of a species to differentiate conspecifics from heterospecific individuals.

 

Because hybrids have highly variablel phenotypes, it is essential to use molecular tests to determine species status. Students will take small tissue samples from the fish and take them back to Lehigh University where they will be trained to perform genetic analyses.