British Butterfly Thrives on Climate Change

Climate change is reviving   a once rare British butterfly, according to a new article in the journal Science.   The brown argus butterfly was once scarce, but has doubled the size of its range in the last 20 years.   The study, authored by biologists at the University of York, indicates that at warmer temperatures brown argus butterflies are able to feed on more common plant species, allowing them to expand into new territory.

Brown argus caterpillars normally feed on the rockrose plant, but they occasionally use plants in the geranium family during warm summers. The rockrose usually lives on sunny, south facing slopes and brown argus caterpillars depended on these warm microclimates for survival. However, for the last 20 years summer temperatures have been on the rise and the brown argus has been shifting it’s egg laying towards geraniums.

During cold summers, the brown argus butterfly uses the rockrose plant (left) but climate warming has allowed it to thrive on the wild geranium (right)

To test whether climate caused the shift in food choice, lead author Rachel Pateman and her colleagues used data collected from 200 sampling sites in southern England.  Butterfly sightings at the sampling locations were reported by volunteer naturalists, and some sites  been monitored since the 1900s.   Each sampling location had only rockrose or only geranium growing nearby.  The researchers used butterfly counts from the volunteer records and matched it to historical temperature data. They found that the butterfly populations grew faster at geranium-only sites during warm periods, and faster at rockrose sites in cool years.

The scientists also looked at  changes in brown argus populations in the last 20 years, when temperatures have been especially warm.  They found that the brown argus had become  5.3 time more plentiful at geraniums sites, but that

The brown argus has nearly doubled the size of its range in the last 20 years. Dark red and blue are locations where it was found prior to 1990, the light blue and pink circles indicate new territory gained in the past two decades. Most gains have been in areas where geraniums are found.

rockrose areas had not changed at all. The butterfly had also expanded it’s range north by 79 kilometers in just 20 years. Co-author Chris Thomas thinks that the common geranium plant may serve as a stepping stone, allowing the brown argus to branch out into new regions without having to fly long distances.  Says Thomas “Wild Geraniums are widespread in the landscape, the butterflies can now move from one patch of host plants to next and hence move rapidly through the landscape expanding their range generation after generation.”

While climate change has been an unexpected bonus for the brown argus, it’s unlikely to be such a boon for other species.  According to Stanford biologist Terry Root (who was not involved in the study), for every species that turns out to be a climate change “winner” there are expected to be three “loser” species that suffer population declines or go extinct.

Teen Lepidopterist Decodes the Secret to Butterfly Sense of Smell

Alexandra Sourakov working in the University of Florida Butterfly house

Alexandra Sourakov has logged hours of research at the University of Florida’s butterfly house.  She used a combination of behavioral experiments and electorantennography (measurements of electrical current in butterfly antennae) to determine how butterflies find food.  Her most recent paper on foraging in Blue Morpho butterflies appears in this month’s edition of Psyche – Journal of Entomology.  Alexandra Sourakov is also about to finish her sophomore year of high school.

Sourakov began her study as part of an eighth grade science project. She used the butterflies in the University of Florida Natural History museum’s butterfly house to see whether flower-feeding and fruit-feeding butterflies responded differently to color. Sourakov used different colored landing pads baited with food to see whether butterflies preferred brightly colored surfaces to black. She found that flower- feeding butterflies were attracted to bright hues, but that fruit-feeding butterflies were indifferent to color. Presumably, flower-feeding butterflies evolved to respond to color cues because they aid in finding brightly colored flowers, while fruit-feeding butterflies usually feed on fruit that has fallen to the dark forest floor, where visual cues would be of little use.

Blue morpho butterflies sense odors with their legs and mouth parts in addition to their antennae, according to a new study by high school student,Alexandra Sourakov

After winning the science fair, Sourakov decided to scale up her research program to investigate how the fruit feeding butterflies found their food. If they weren’t using color, how did they find fruit? Partnering with USDA researcher and science fair judge Adrian Duehl, she launched a multi-faceted approach to understanding butterfly foraging. Sourakov and Duehl used gas chromatography to determine what chemicals in rotting fruit might be attractive to butterflies. They applied these chemicals as volatiles to the antennae of Blue Morpho and Owl butterflies. These two fruit-feeding species did not show any preferences for color during the experiment. With the help of electrodes, they measured the electrical output when the butterfly was exposed to different chemicals. They found that several chemicals that give bananas their distinctive odor provoked a response in the butterfly antennae. Even more interesting, they found that it wasn’t only the antennae that registered a response of the chemical, the legs and proboscis (feeding tube) also responded to the scents. The labial palpi (mouth parts on a butterfly’s head below the antennae) reacted to a different set of chemicals, indicating that butterflies may use multiple organs to detect a variety of odors.

“I was surprised by the results from the body parts because I wasn’t even sure if any of them, except the antennae, would react to the volatile chemicals,” said Alexandra Sourakov in an interview to the University of Florida News. “This was interesting because it shows a joint message may be sent to the brain from these different organs. This expands our understanding of butterflies’ sense of smell.”

The researchers hope that their work will allow them to develop new types of bait designed to target specific species of insect, while leaving other species unaffected.  You can read Alexandra’s full article here:

Early spring meltdown a threat to butterflies and flowers

Spring has been coming early to the Rocky Mountains, and while warm weather may be good news for humans, it’s bad news for flowers and butterflies. A  long term study by Carol Boggs (Stanford University) and David Inouye (University of Maryland) shows that early snowmelt causes a decrease in flower populations, which in turn means reduced food for the mormon fritillary butterfly. In years where the snow pack melted early, spring frosts often damaged newly emerged plants, and the butterfly’s preferred flowers became scarce.   Caterpillars were also casualties of this early spring thaw; butterfly larvae emerged before the danger of frost had passed and were often victims of sudden freezes. The Rocky Mountains are warming faster than other parts of the country, so the effects of early snow melt are expected to worsen in coming years.

The Rocky Mountain Biological Laboratory in Gothic, CO

Mormon fritillary caterpillars have an unusual life cycle that makes them especially vulnerable to climate change: their eggs hatch in late summer before snow fall and caterpillars hibernate under the snow pack until spring.  Early snow melt can be  a  false alarm for caterpillars: if they come out of hibernation before the danger of frost has passed, they may perish in a sudden cold snap.  Adult butterflies are similarly affected by spring frosts.  Females depend on nectar to produce eggs, and early frosts can kill  newly sprouted flowers. In years where flowers are scarce and butterflies are abundant, females must compete for food and produce fewer eggs, resulting in smaller butterfly populations the next spring.

Boggs has been studying the mormon fritillary for 34 years at the Rocky Mountain Biological Laboratory (where Jessica and Heidi do their field work).  She and Inouye wanted to use this long term data set to  test whether early warming had an effect on butterfly populations.  The researchers combined  flower surveys with butterfly population counts from 1980 to 2005, and used this data to build a mathematical model to see whether the number of flowers and the snow melt date in a given year could predict how many butterflies emerged in the spring.  They found that the number of flowers per female was a good predictor of butterfly populations the next spring. However,  flowers alone didn’t explain the population declines: early snow melt also decreased butterfly populations in the following year through caterpillar mortality.  Together, these two factors explained 84% of the variation in butterfly populations.  The study showed that climate can affect a species in two ways, indirectly through it’s food chain and directly through temperature stress.

Boggs and Inoye were able to detect this pattern because their data set spans three decades. Long term studies like this one are the only way to accurately detect the effects of climate change. Becasue there can be substantial variation in temperature from year to year, it may take decades to understand how slow shifts in climate affect wildlife populations. The Rocky Mountains are a particularly important location for climate change research because they are a warming hot spot. The american west is warming 70% faster than the global average, and temperature data from Rocky Mountain Biological Laboratory shows that the average temperature has increases 0.72 degrees F per decade. While that sounds small to a human, it can mean big problems for butterflies and flowers.

If you want to follow the weather at the Rocky Mountain Biological Laboratory, you can find weekly updates  here

To read the full paper:

Boggs, C., & Inouye, D. (2012). A single climate driver has direct and indirect effects on insect population dynamics Ecology Letters DOI: 10.1111/j.1461-0248.2012.01766.x

Science Online 2012

This week Jess and I attended the Science Online 2012 conference in Raleigh.  This so -called  “un-conference” is designed to bring together scientists, science writers, educators, and bloggers of all stripes to learn about using the web for science communication.  The conference was an amazing experience, and I met so many people doing cool things.  Although pretty much every session or workshop was incredible, I narrowed my list down to my five favorite things about Science Online. Before I start the list,  I have to thank the National Evolutionary Synthesis Center, who gave me a scholarship so I could attend.  It was a real honor to be selected, and I’m really grateful that I got to go to this amazing conference.  Also, look for Grad Student Jess’s post soon about her favorite things from Science Online 2012!

Five Favorite Things About Science Online:

1.  The constant tweeting! Lots of conference goers chose to live-tweet the workshops and sessions at Science Online.  At first I found the constant tweeting a little overwhelimng, but pretty soon I was compulsively checking twitter with the rest of the crowd.  It was great to be able to see what was going on in other sessions, and it provided a fun record of everything that went on at the conference from insightful comments to the location of free ice cream.  Below a map of all the tweets at Science Online (Jessica and I are in there somewhere!)


Science Online 2012 Tweet Map

2. A special science themed story slam by The Monti! Some readers may be familar with The Moth, a live storytelling event in which people (often young, bespectacled Brooklyintes) share funny, sad or surprising stories with a live audience. It’s like stand up commedy, if standup commedy hit a nerve as well as tickled your funny bone. The Monti is a local version of the Moth, run by Jeff Polish a former scientist turned story teller.  Ben Lillie of Story Collider (another great story telling project) performed too! I’ll definitely be attending their other non-science shows around Chapel Hill and Durham.

3.  A stand up set from science comedian Brian Mallow

4.  Map making workshop taught by Tim De Chant, who writes the awesome blog Per Square Mile. Understanding how species move across the environment is such an important part of my work, and sometimes you just need a good map to make your point. We learned about some cool, open source map making  and spatial analysis tools, like QGIS .  Look forward to some cool maps and graphics on the blog!

5.  Sketchnote seminar taught by Perrin Ireland of Alpha Chimp Studios, a company that teaches visual brainstorming.   Sketch-noting is a style of visual note taking, and is a popular way to share ideas from meetings and conferences.  It also helps you remember information and pay attention too!  The famous TED talks lecture series uses visual note taking so attendees can learn about talks they’ve missed.  Here’s a quick overview of visual note taking from the pioneer of the field, Sunni Brown.

Coming soon: Jess’s take on Science Online.

Prehistoric Moths Show Their True Colors

Happy 2012 butterfly fans!  In order to better celebrate the future, we’re taking a  look back into the past: the ancient past.  The earliest known butterflies and moths evolved about 50 million years ago (although there is some evidence that they might be even older and have coexisted with the dinosaurs).  However since fossils are pretty drab, nobody really knew what the ancient butterflies looked like until recently.

Butterfly scales reflect light to produce colorful patterns

Now scientists at Yale  have used fossilized moth scales to figure out what color ancient moths and butterflies were.  Butterfly wings get their vibrant hues from  scales that reflect light to produce colors and patterns.   These so called “strucutral colors” are produced by layers within the scales that reflect light like a prism.   The research group, led by Professor Maria MacNamara, analyzed the structure of the fossilized moth scales to determine how they would have reflected light, and therefore what color the moths would have appeared.

MacNamara's reconstruction of the fossil moth. The bright colors likely served as a warning to predators

The moths turned out to be bright green with blue wing tips, which means they would have been conspicuous as they fed on flowers in ancient forests.  However, the closest living relative to the fossil moths, the forester moth, also uses bright colors to warn predators that it is toxic.  MacNamara and her group think that ancient moths may also have been able to store toxins to ward off predators and used their colorful wings to deter attacks.    These results are exciting to biologists as well as paleontologists because they show that predator-prey interactions were as important in the ancient past as they are today.

McNamara ME, Briggs DE, Orr PJ, Wedmann S, Noh H, & Cao H (2011). Fossilized biophotonic nanostructures reveal the original colors of 47-million-year-old moths. PLoS biology, 9 (11) PMID: 22110404

New Atlas Maps all 441 Species of European Butterflies

Butterfly Biodiversity in Europe. The areas of highest biodiversity are in the alps and the mediterranean.

Get excited, because the Distribution Atlas of Butterflies in Europe was released today, and butterfly scientists will be lining up around the block to get their hands on a copy.   The new atlas gives detailed maps of the ranges of  all 441 butterfly species found in Europe.  The new maps were calculated with computer mapping software from a whopping 655,000 field observations of butterflies all over Europe.  To produce this massive book on butterfly biology the highly efficient team of German scientists in charge of the project got help from 272 volunteer naturalists.   The map is just one more reason that I need to move to Europe, because we don’t have maps nearly this detailed or recent for North American species (although will definitely give you all your basic butterfly facts if you’re interested).  I often spend a lot of time looking for butterflies where an old field guide said I could find them, only to find out that that population has gone locally extinct.  North American, lepidopterists, please take note!

The atlas will be useful both in identifying sparse populations, and identifying areas where there is high butterfly biodiversity for conservation.   One in three butterfly species has a range less than 1% of the area of Europe.  Put another way, most butterfly species can be found only in an area smaller than Portugal.   It’s a good thing someone is keeping track of them.

Butterflies and Social Science

One of the really fun things about my fellowship  in Japan was meeting other students from different  fields.  One person who does especially cool work is my friend Annabel Vallard, who is a postdoctoral fellow at the Center for South East Asian Studies  in Paris.  Annabel is an anthropologist who studies the silk production in Japan, Thailand, and Laos.  As I mentioned before, Silk worms are not technically butterflies.  However, they are in the same order (Lepidoptera), and I didn’t want to pass up the chance to interview a butterfly social scientist because of a technicality.

Silkworm farmer in Laos posing with a tray of silkworms

Annabel got interested in silkworms when she was studying textile industry in Laos and Thailand for her thesis. Since silk weaving is an important craft in the area, she started talking with rural silk producers about how they raise silk worms.  One thing she found out was that the Japanese government had started a collaboration in Thailand as early as the first decade of 1900’s and in Laos during the late 1950s in order to improve silk quality and to help impoverished Laotian and Thai silk farmers. Japan as a nation is very committed to international development and aid, and often sends its scientists abroad to do research or teach in developing countries.  Annabel’s work in Thailand and Laos focused on interviewing the silk farmers and the Thai and Laotian staff at the research station about how they raised silk worms as well as how they interpreted the scientific research and protocols for silk worm care.  Although scientists try to accurately follow standard protocols for their research, every person will perceive these instructions differently, and each culture has its own way of interpreting the same directions.  She’s now starting a new phase of the project here in Japan, trying to find the Japanese scientists who worked on the silkworm development programs in Thailand and Laos and to find out not only what they did in the project but what their current relationship to silkworms is.

Development programs and Silk

Even though the Japanese government started the program with the best intentions, silk

Postage Stamp Promoting Silkworm Production in Laos

production in Laos and Thailand was (and still is) a pretty different process from silk production in Japan.  In the previous blog post, I explained how the Meji emperor was influential in developing the science of silkworm breeding and rearing.  By the 1950s, silk production was a highly industrialized process in Japan, and silkworms were raised in sterile laboratories on artificial diet. However, Thailand and Laos were still using traditional methods of silk production.  Silk is still produced by individual households, where silkworms are raised in bamboo trays behind the kitchen and are fed mulberry leaves from the garden around the house.  At first, Japanese researchers tried to introduce the Japanese species of silk worms. However, the laboratory bred silkworms had evolved in sterile conditions and at cooler temperatures.  When they were crammed together in bamboo trays in the humid atmosphere of Laotian and Thai homes, they would get sick and die.  Eventually Japanese researchers hybridized the Japanese lab silk worms with Laotian and Thai native silkworms, and they produced a strain that could survive in the tropical heat in people’s homes. Today in Laos the Japanese government ships the research stations these special eggs produced in laboratories, the research station staff raises them, breeds the adult silkworms and supervises their reproduction. Then, they sell the new generations of eggs to local silk farmers that will raise them to maturity. More than half a century later, the Lao-Japanese program is still going, and every few years the Japanese government sends a diverse team of scientists to the field station to continue the research efforts.  The research team usually includes entomologists, soil experts, silk machinery engineers and silk worm disease experts.  Annabel’s new project is to find researchers who have participated in the project and to explore the manufacture of these biotechnological materials altogether in human imaginary and in practice. Annabel is interested in more than just silk worm raising technique though.  Just like Jess and I are interested in using butterflies to understand big questions about how insects can evolve in a changing climate, Annabel is interested in studying how two cultures can go about the same process in different ways, and what happens when people from those cultures try to work together.

A Day in the Life of a Butterfly Social Scientist

research station staff washing silkworm trays

Jess and I have talked a lot on the blog about what the daily life of a butterfly biologist is like.  Annabel’s work schedule is really different from that of a biologist.  Modern anthropologists use a method of data collection called “participant observation” where they try to become a part of daily life in the community they study.  They go about mundane tasks with the people while trying to observe and record what they are actually doing.   Since Annabel is just beginning her research here in Japan, her work right now consists of meeting with scientists and trying to track down the researchers who worked on the Laotian and Thai development projects.  In Thailand and Laos, however, her work day takes her to the silk research stations where she works alongside the staff to see what they’re doing.   If they’re breeding silkworms, cleaning cages, or answering questions from silk farmers, she’s right there watching how they work and sometimes working with them.  When they stop for a tea break or go out for a beer after work, she goes too.

While Jess and I use a lot of lab equipment, Annabel just uses a list of questions and a tape recorder or video camera to watch how people work.  She says recording is really important because it’s easy to miss something while you’re thinking of your next question.  However, it’s not just a simple interview process and you have to be a strong observer to catch and remember the smallest details.  Annabel says that you have sometimes to let your research subjects lead the conversation, and be flexible when they surprise you with a new topic or idea.  “In anthropology you have to be open to what will happen next”, she says.

Ethnoentomology: The Social Science of Insects

When I asked Annabel what surprised her the most when she started the silk worm project, she said “the fact that people can have such strong relationships with insects.”  Annabel says that there is a growing field related to anthropology called Ethnoentomology.  You may have heard of Ethnobotany, the study of how communities use plants, and Ethnoentomology is basically the same thing but for insects.   In the past, anthropologists usually studied human-insect interactions when insects were part of food, myths or ceremonies.  Now anthropologists are becoming interested in how people organize economic and social institutions around insects.  Most ethnoentomologists do this by studying a small scale example in detail.  For example one of Annabel’s colleagues, Nicolas Césard, studies urban bee keeping  in  France while another, Stéphane Rennesson, studies beetle fighting rings in Thailand.  Of course, biologists like Jessica and I are part of a community with our own beliefs, hierarchy and rituals surrounding insects.   Biological scientists are now becoming the subjects of research themselves, as anthropologists try to understand how the scientific community works .  While it can feel a little strange to be under observation yourself, I think it’s great that we have social scientists to help biological scientists understand the way we do our job.