ScienceBlogling Mike Dunford has an interesting post asking whether we should save an endemic Hawaiian plant, the williwilli. It’s a good post, but I have two comments, one silly and one serious. The silly comment is that how could anyone let a plant named the williwilli become extinct? It’s so damn cute (and is the plural williwillies?) Onto the serious point.
The reason that the williwilli is in trouble is because an invasive, non-native gall wasp is parasitizing the williwilli. Mike writes:
…if the invasive species outcompetes the natives, resulting in the extinction of the native species, it is simply a case of natural selection.
Here’s the serious point: I don’t think calling this natural selection is accurate. This is an example of an ecological interaction, parasitism. While the survival of the williwilli is affected, this interaction isn’t natural selection. For natural selection to be taking place, gall wasp parasitism must result in the differential survival of williwillies. In other words, plants that are more resistant to the wasps must replace plants that are more sensitive to the wasps as a result of the parasitism. Mind you, this could be happening, but I haven’t found any papers suggesting this.
To paraphrase Freud, sometimes parasitism is just parasitism.