Last updated November 29, 2017 at 4:44 pm
When a snail kite is hungry, it only looks for one thing – a tasty little apple snail, native and plentiful to the healthy state of its North and Central American wetland habitats.
These raptors are perfectly adapted to make a meal of apple snails, with beaks and talons just the right size to scoop meat out of the shell. But in areas of Florida, another – much larger – invasive species of apple snail has taken over in the last 15 years.
Recent research has shown, in direct response, a rapid change in the local snail kite population. Researchers tagged and banded populations of the snail kites and took measurements of the birds as they grew. They also took feather samples to run genetic analysis. They were able to show that overall beaks and relative body size increased substantially over the last decade. This is less than two reproductive generations, and coincides with the recovery of their overall population numbers.
However, this change isn’t an example of rapid evolution in action – although it does indicate that evolutionary change is just around the corner. Instead, it’s caused by something called phenotype plasticity. This basically means that an organism can express and develop different characteristics – whether these are how the organism behaves or how it looks – depending on its environment.
Generally invasive species are seen as the rapidly adaptable ones – and this is true, it’s one of their defining characteristics and what makes them such a threat to otherwise healthy ecosystems. But it is heartening to see evidence that long-lived invertebrates can also adapt to changing conditions.
This research was published in Nature.