Tuesday, June 4, 2019

Perspective in Science

Threespine stickleback, the protagonists of the research article that we wrote a perspective piece for,
are a model for understanding how repeatable evolution is. This is because populations of these little fish have independently evolved to live in freshwater lakes and streams all over the Northern Hemisphere.

Repeated adaptations to life in freshwater range from anatomical features like losing armoured anti-predator defences, to growing and reproducing faster, to digestive enzymes that compensate for the dearth of fatty acids in freshwater diets.

Life in freshwater does not just involve new predators and new food sources, but also new parasites. Below is an illustration (not to scale) of the life cycle of some of the key tapeworm parasites than infect freshwater stickleback. Eggs and larvae are eaten by little crustaceans such as copepods, as depicted on the bottom of the figure. Stickleback, such as this male guarding his nest, become infected when they eat copepods full of tapeworms. Birds, such as loons and mergansers, distribute tapeworm eggs across different watersheds when they eat infected stickleback and poo out tapeworm eggs. As a result, while the stickleback in each watershed are on isolated evolutionary trajectories, they are constantly coevolving against parasites like tapeworms, with a much more global distribution. This system provides a perfect natural experiment for understanding how host immune systems evolve different ways to combat a single parasite.

Wednesday, May 1, 2019

In memorium: Henry Horn

In the acknowledgements section of my PhD defence, I drew Henry as a male satin bowerbird, as a tribute to his inventiveness, artistry and intelligence. By analogy, bowerbirds are also much less personally showy than their posturing relatives, the birds of paradise. Henry is easily the most unassuming yet brilliant people I have ever known.

He is also a great inspiration to those who are equally inspired by the art in science and nature as by the nature of art. There is no better embodiment of a Renaissance man than Henry Horn. Inventor, naturalist, mathematician, artist, poet, musician, craftsman, beloved teacher, environmentalist, humorist, lifelong explorer of the natural world.

I have never met another person who so genuinely enjoyed sharing his diverse passions with others, yet managed to make anyone feel as though each conversation with him was a comfortable, cosy chat between kindred spirits. Henry always made one see the humour in a situation and to think deeply. This is probably because of his consummate ability to do both simultaneously. The door to his office was covered in jokes, often against himself. There was a copy of a letter threatening failure at Harvard if he didn't pull up his socks academically. Also a photograph of himself at a more tender age, with a caption along the lines of "such a cute kid, where did it all go?". Once you entered, he would have original and thoughtful comments on any subject.

Some of the best pieces of advice on writing comes from Henry, and I pass it on to students all the time. 1. Read good writing, and lots of it. Preferably Jane Austen. 2. Read what you've written aloud, and if you stumble, that's a sure sign the sentence is clumsy.

There are far too many memories to list, but I speak for assorted strays and aliens who benefitted from Henry and Betty's hospitality at Thanksgiving. Their beautiful home at Stony Ford was where I had the pleasure of first encountering J. Chester's gallery and the LiWA, short for Little Wooden Animals, which accompanied him and Betty to some spectacular places. I am also personally grateful to Henry for choosing my book prize when I graduated from EEB. The last time I visited him, he showed me his children's books and lesson plans with the LiWA as protagonists, played the guitar, and showed me the new public library building at Princeton, all on top of discussing bird behaviour over Subway sandwiches.

Unlike many scientists of his stature, Henry had a deep and abiding respect for all students of nature. He spent so much time teaching and exploring with everyone, from schoolchildren to lost undergraduate and graduate students, that his intellectual legacy through other minds is immense. Now that I can no longer pop in for a chat, every memento and memory of Henry will be all the more precious. I shall be taking a walk in the woods this Sunday as I can't attend his memorial service.

Saturday, January 12, 2019

Birding Bali Barat National Park

 Bali Barat, or West Bali National Park, is in the northwestern corner of Bali, 4 hours drive through mountains and rice terraces from the madding crowd of tourists that cluster around the beaches in the south. This park was set aside as the last habitat for the Bali starling or mynah, which is found only on Bali. These beautiful birds became critically endangered due to persistent poaching for the caged bird trade, and there are now over 1,000 individuals in captive breeding programs around the world.

Fewer than 100 Bali mynahs remain in the wild, all of which gather to breed here in the park. We were lucky to see a flock of 12 birds flying from tree to tree as we stood on a hillside looking out over the forest canopy on our first morning. The next day, we found four pairs, garrulous and stunning in their startlingly white suits and brilliant blue spectacles.