Snorkeling with hybrids in the Solomon Islands

It’s not often that we come across a naturally occurring and rather obvious animal hybrids while snorkeling. That said, there is one relatively common hybrid that exists in the Solomon Islands and the species is easily observed. It is the beautiful White bonnet anemonefish (Amphiprion leucokranos), which can show variable color patterns and lives with a number of symbiotic anemones. This unusual anemonefish is commonly found with other species of anemonefish in their host anemones and there has been a long-standing theory that A. leucokranos was a cross between Orangefin anemonefish (A. chrysopterus) and Orange anemonefish (A. sandaracinos). Using genetic evidence and field observations this theory has recently been proven correct.

Interestingly, due to a strict size-based dominance hierarchy and protandrous hermaphrodite life history, the larger Orangefin anemonefish always act as females while the smaller Orange anemonefish serve as mating males. While snorkeling on our recent Solomon Islands adventure we were able to observe several examples of White bonnet anemonefish living with Orange anemonefish that had spawned and were protecting a healthy patch of eggs. This observation points to there being hybrid backcrosses and genetics being mixed freely within this population of White bonnet anemonefish. It also brings up the question of what a “species” really is. How we define “species” or “subspecies” does not always explain what actually exists in Nature. Whatever the case, it is absolutely fascinating that we can detect natural selection and the processes of evolution while snorkeling.