As WeDigBio rapidly approaches, we have one last batch of Swallowtail butterflies ready for transcription — these from the American Museum of Natural History. By now you (and I) may have seen quite a few of these large, colorful butterflies. Do we really need more?
Yes! I’m working toward understanding variations in wing shape across the full geographic range and diversity of the group. Some museums have particular strengths in certain parts of the world, and more established museums like the American Museum and the Smithsonian (remember that batch from last month?) have specimens that are particularly rare and historic. This is valuable to me because I want to examine specimens from all species of New World Swallowtails, and this trip to the American Museum completed my collection of digital images.
I was particularly excited to come across several specimens of the Esperanza Swallowtail, Pterourus esperanza. These were the first I had seen in visits to three other major museums and searching through thousands of specimens. Esperanza Swallowtails are found only in the cloud forests of the Northern Sierra in Oaxaca, Mexico, and weren’t even described until 1975. A 2013 study estimated the population size to be 286 individuals. The precious few specimens at the American Museum can help give us insight into the evolutionary context for this rare and enigmatic species. That understanding can hopefully help better conserve this and other swallowtail species.

Keep an eye out for these neat oddities as you transcribe. They’re a treat!

--Originally posted on Notes From Nature blog, 17 October, 2017

This update was a little slow in coming, but we had a new paper come out recently that highlights some of the benefits of using large citizen science datasets to understand invasion dynamics. Specifically, we looked at the well-documented invasion of Eurasian collared doves in North America following their introduction in Florida in 1989. Our study benefited in large part from collared dove sightings by birders posted to the eBird website, by which we could track new locality records as the species spread. It turns out all that compulsive list-making can really benefit science!

In the paper, we wanted to understand how the rate of invasion of collared doves in North America related to the position of invaded habitats within the suitable abiotic niche of the species. That's a mouthful. Let's step back. Think about it this way. In a given location, there will be an annual mean temperature, annual precipitation, etc. The combination of these variables at this location can be thought of as its position in "niche space" just as its latitude and longitude describe its location in geographic space.

In the paper, we inferred the dimensions of abiotic niche space (i.e. temperature, precipitation, etc.) suitable to collared doves based on its known distribution. We then looked at records of the expansion of collared doves as they invaded North America. We then calculated the position of the invasion front in niche space every year to see if doves moved faster in more suitable habitat. This was our hypothesis, since we thought more comfortable habitat would lead to more offspring being produced and consequently more birds to disperse and invade.

What we found was actually the opposite! The invasion moved faster through unsuitable habitat. We hope in the future that these methods can be used to explore other well-documented species invasions to see if this pattern is the exception, or a hint at a new paradigm for invasion dynamics.

Citation:
Ingenloff, K, CM Hensz, T Anamza, V Barve, LP Campbell, JC Cooper, ED Komp, L Jimenez, KV Olson, L Osorio-Olvera, HL Owens, AT Peterson, AM Samy, M Simões, J Soberón. 2017. Predictable invasion dynamics in North American populations of the Eurasian Collared Dove Streptopelia decaocto. Proceedings of the Royal Society B 284: 20171157. doi: 10.1098/rspb.2017.1157

Article link: http://rspb.royalsocietypublishing.org/content/284/1862/20171157