What I did on my summer vacation: Trip Report from the Mono Lake Bird Chautauqua

I just got back from one of my favorite events of the year, in one of my favorite places in California- the 14th annual Mono Lake Bird Chautuaqua in Lee Vining
The Chautauqua is a 3-day festival that celebrates not only birds, but the beauty and natural history of the Mono Basin, eastern Sierra Nevada, and the Great Basin. The long weekend is packed with field trips, presentations, and social events put on by people who are dedicated to protecting this important natural area and sharing its beauty with the over 400 participants who come to partake. I was looking forward to this trip for months, ever since the organizers got in touch and asked if I could lead a bug field trip. This would be my third Chautuaqua as a trip leader, and Zach’s fifth- sadly we had to miss last year’s event for crazy scheduling issues on our end. One of the wonderful things about the Chautauqua is getting to spend time with so many great people. It sounds cliched to say this, but I love getting to reconnect with old friends and make new ones- and every year it seems like we meet great new friends who I will look forward to catching up with the next year. This year was no exception.

If you’ve never been to Mono Lake, what are you waiting for? GO! NOW! I’ll wait…
The lake itself sits at the base of the eastern slope of the Sierras, just over the hill from Yosemite National Park and Tuolomne Meadows, at an elevation of almost 7000 feet. Highway 395 runs the length of the eastern Sierra, and while a few small towns dot the road, the whole area feels gloriously, luxuriously quiet and deserted after a year in Los Angeles. Mono Lake itself is formed from streams running out of the Sierras and draining into the Mono Basin. The lake has no outlet, so the water that collects has been subjected to eons of filling and evaporation cycles, concentrating salts and minerals in the water and driving the salinity levels higher than that of seawater. The lake supports an incredibly productive ecosystem, driven largely by brine shrimp and fly larvae that support migratory and breeding birds in spring, summer and autumn.

For a natural history enthusiast, Lee Vining offers spectacular scenery, clean air, and the promise of seeing lots of birds (or bugs, or whatever your pleasure) across a variety of different habitats. To the east, the sagebrush desert of the Great Basin stretches out as far as the eye can see, interrupted periodically by hills and mountains jutting up out of the landscape in dramatic fashion. To the west, the granite and metamorphic cliffs rise steeply upwards, quickly becoming snowcapped alpine peaks over 10,000 feet high- at least, in most years. California is in the 4th year of a well-publicized drought, and even after living here for a year, we were still shocked and saddened to see how dry the mountains are this year. The lack of snowpack in the Sierras is causing issues over a large part of the state as municipalities such as Los Angeles struggle to conserve what little water is available, and coming to Mono Lake is a stark reminder of just how severe this drought is. Much of Los Angeles’ water comes from the eastern Sierra, and the landscape around Lee Vining is dotted with signs warning would-be trespassers to stay off of the property, as it is now owned and controlled by the LA Water District. All Angelenos should come to Mono Lake and the Owens River Valley and witness for themselves just where their water is coming from, and what that water means to the wildlife that calls this area home.

My biggest regret of the weekend is that I forgot to get a group photo from my field trip.  The good folks who came along on my field trip Sunday morning were absolutely fantastic, and made my job as a presenter so easy.  I just wish the wind would have let up a bit so that we could have seen more butterflies, but I personally still had a great time.
I could easily spend a few thousand words extolling the virtues of Mono Lake, Lee Vining, the eastern Sierra, and of course, the Chautauqua. But I think instead I’ll put up some cellphone pictures of the long weekend, and leave you with an invitation to join the fun in 2016. Registration usually opens in the spring, and some of the programs fill up fast! Put it on your calendar!

Why Mimicry is the Coolest Thing Ever, Part 2: Mimicry Can be Mutually Beneficial

A while ago I wrote about the phenomenon of mimicry, and talked a bit about the earliest descriptions of mimicry.  In Batesian Mimicry, two species have converged on the same conspicuous “warning” phenotype, but only one is giving an honest signal.  In the case of butterflies this phenotype is usually warning coloration, or aposematism.  The honest signal indicates that the animal is toxic, and the animal who is giving this signal is called the model.  Predators that encounter the model have a bad reaction, associate it with the aposematic signal, and avoid prey with that phenotype in the future.  Mimicry comes in when another species, the mimic, is perfectly harmless but benefits from sharing a similar phenotype with the model.  Predators either can’t tell the difference between the two species, or aren’t willing to take a chance, and therefore avoid the harmless mimics.  Mimics get protection from predation by virtue of their false warning coloration, plus they don’t have to pay the metabolic cost of sequestering toxins in their bodies.  Henry Walter Bates first described this type of mimicry while studying butterflies in the Amazon.

Some of the many diverse mimetic Heliconius phenotypes

Some of the many diverse mimetic Heliconius phenotypes

In 1878, Fritz Müller proposed another type of mimicry after studying some of the same butterflies in Brazil that Bates had investigated.  These specific cases had puzzled Bates, but Müller realized that mimicry doesn’t always involve a dishonest signal.  Like Batesian mimicry, this type of mimicry was eventually named after the naturalist who first described it.  In a Müllerian mimicry system, two or more species strongly resemble each other and are poisonous to common predators.  The burden of educating a predator to avoid a specific color pattern is shared between both species, and some biologists consider it a form of mutualism.

Monarch butterflies were originally believed to be Batesian models to Viceroy butterflies after a pioneering study performed by Jane Van Zandt Brower in 1958 indicated that naive Blue Jays would reject Viceroys after exposure to Monarchs.  The story wasn’t that simple, though, as David Ritland and Lincoln Brower showed later that Viceroy toxicity varies geographically (and, actually, so does Monarch toxicity).  In some areas, Viceroys are not poisonous, and if they coexist with Monarchs, they are Batesian mimics of Monarchs.  In other areas, though, Viceroys sequester toxins from their caterpillar host plants (often salicylic acids from willow trees) and function as Müllerian mimics.  Even more interesting, Viceroys also coexist with Queens in some places.  Queens and Monarchs are closely related, both sequester toxins from milkweed plants, and both are toxic.  This means there are many combinations of species pairs and mimicry types possible just within this one group: Monarch + Viceroy can be Batesian or Müllerian mimicry; Monarch + Queen is Müllerian mimicry; and Queen + Viceroy can be Batesian or Müllerian mimicry.

Queen butterflies ingest poisons from the milkweeds that they eat as caterpillars.  The caterpillars and adults become toxic to predators.

Queen butterflies ingest poisons from the milkweeds that they eat as caterpillars. The caterpillars and adults become toxic to predators.

Today some of the strongest research on Müllerian mimicry comes from researchers studying butterflies of the genus Heliconius.  Heliconians occur in the tropics of Central and South America, and there are about 39 recognized species within the genus.  They occur in many different species combinations and a variety of color pattern phenotypes.  They take in amino acids from feeding on pollens, and these compounds allow them to make cyanic compounds- cyanide.  Published studies on Heliconius mimicry have exploded in recent years, and have led to an understanding of the genetic mechanisms controlling color evolution, the physiological processes that protect the butterflies from the poisons they are carrying, the behavioral interactions that allow butterfly species to tell each other apart and find suitable mates, and many other things.