Archive for October, 2010

An Interview with Professor Jonathan Snow

Jonathan Snow, Visiting Assistant Professor of Biology at Williams College, received his B.A. from Williams College in 1996, after which he completed his graduate studies at UCSF and his post-doctoral training at Harvard Medical School on the effects of transcriptional regulation in immune system development.  He decided to come back to Williams to teach and to continue his research on immune development, using the honeybee as his model.

As one of his seminar students, I was given an opportunity to interview Professor Snow on his research interests and his thoughts on teaching at his alma mater.

October 26, 2010

Joshua: Tell me about the kind of research you did before honeybees.

Professor Snow: My career before honeybees involved understanding the mechanisms of blood cell development in mammalian models, primarily in mice.

J: Was this the focus of your research for doctoral and post-doctoral research?

PS: Yes.  I was a graduate student at UCSF, where I studied the role of specific transcription factors in blood development and autoimmunity.  I did my post-doctoral work at the Children’s Hospital in Boston on the molecular mechanisms by which genes are turned on and off in mammalian blood development.

J: What got you interested in honeybee research?

PS: I wanted a change of direction, which is common for scientists leaving their postdoctoral work to go to more permanent positions.  I had been interested in food production and sustainable agriculture, and I was looking for ways to tie that to the molecular level questions I had been asking.  I randomly enrolled in a beekeeping class with the Essex County Beekeepers’ Association and realized that honeybees might provide the perfect way to join my two interests.  Many of the molecules that I had previously studied in blood development are present in bees as well, specifically those involved in blood cell development and immune function.

It was exciting to me that the science I was working on could be applicable to help an organism in crisis that is really important for agricultural and natural ecosystems.  Switching to honeybee research was also a big opportunity, because it gave me a chance to change to work on something I was really enthusiastic about, and you don’t get many chances to do that.

J: What specific areas are you interested in/are you researching now?

PS: Right now I’m looking at the honeybee gut as an immune organ.  This actually goes back to some of my first research interests in immune cells involved in resisting pathogens in the gut.  In that work we were looking at damage to the gut caused by the immune system in the gut reacting inappropriately in autoimmunity. As the gut represents an important immune barrier, this destruction can have serious consequences for health.

J: Why is the gut such an important barrier?

PS: Bees are social insects that are in constant contact, sharing and passing food among other things, and in this way they are very much like humans.  A lot of pathogens can be quickly shared in a social group through this behavior and gut exposure.

J: There are many hypotheses that explain Colony Collapse Disorder.  What is your take?

PS: Yes, there are lots of hypotheses, and I think jury is still out on the cause or causes.  However, I think it is likely a combination of habitat loss, changes in beekeeping practices, chemical exposure to environmental toxins, and emerging pathogens.   Once bee hives are weakened through some combination of environmental stresses, pathogens can cause hive collapse.  An understanding of how bees fight pathogens will be crucial to our response to Colony Collapse.

Even winter weather puts stress on hives.  Overwintering is difficult for honeybees in colder climates, as it closes bees inside the hive for longer periods of time and there are few nectar sources during this part of the year.  If the hive cannot quickly gather food and produce larvae in the spring, there can be major consequences. This nutritional stress coupled with a long incubation time stuck in the hive can lead to pathogen buildup further eroding hive health and potentially leading to its destruction.

J: What is the honeybee’s food source during the winter?

PS: It’s the honey they make!  Honeybees take nectar back to the hive, regurgitate it and put the nectar into wax combs.  They then manually evaporate the nectar until it is about 17% water, the rest being sugar from flower nectar.  It’s a very good storage method for sugar: it’s so dry that microorganisms can’t live in it.  It’s analogous to salting meat in order to preserve it.  The nectar is essentially dried out.  In addition to honey, pollen is also stored in the combs as a protein and fat source.  I actually think pollen tastes good!  A very strong taste.

J: Anything else about bees that captures your imagination?

PS: Honeybees together create what is called a superorganism: the hive shares traits that we would normally associate with organisms.  Honeybees work together and the level of organization and efficiency within the superorganism is amazing.  It reminds me of the complex feedback mechanisms in mammalian bodies.  The hive is carefully controlled, but there is no one bee that makes decisions.  They all reach a rough consensus, even though all have genetically diverse ’opinions’.  For example, the majority of bees must agree when the hive will stop rearing larvae for the winter.

J: Any thoughts as to why bees are so social and hierarchical?  Is there an evolutionary answer to this?

PS: I’ve read that superorganisms like bees and ants only represent about 2% of all insect species but about 70% of insect biomass on Earth.  Bees are very good at what they do.  The benefits of social organization are easier survival and perhaps the monopolization of food sources.  A whole hive of bees can outcompete other insects for food sources.

J: You’ve switched gears a little to teach at Williams.  What inspired you to come back?

PS: I had a really good experience in the Williams College Biology Department – seeing good teachers in action at the front of the class made me think that it would be really fun to stand up there and teach as well.  Being able to come back to teach for the alma mater for a few years seemed like a great opportunity.  It’s been a lot of fun!

All the complicated life in the hive …

“Most people don’t have any idea about all the complicated life going on inside a hive. Bees have a secret life we don’t know anything about.” -August in The Secret Life of Bees

For several years now, people have been wondering what, exactly, is happening inside the hives of honeybees.  Colony collapse disorder has been decimating hives, confounding beekeepers, and even causing a low-level panic in the general public.  Just a few moments ago, the New York Times published an article announcing a modicum of success in solving this mystery, “Possible Cause for Bee Die-Off Found,” by Kirk Johnson.

Entomologists and military scientists have found a fungus that is apparently working in tandem with a virus to somehow compromise the bee nutrition.

Lots of questions still to answer … but let’s hope this is a first step in identifying the problem or problems and working toward a solution.

It’s well past time to unravel this particular piece of complicated life inside the hive!


10 2010

Mellow Yellow: Lovely Lindera Benzoin, North American Native Spicebush

Lindera benzoin at Fercliff in late September (planted here with Juniperus chinensis ‘Sargentii’ and Ilex verticillata ‘Red Sprite’)

Lindera benzoin (Spicebush) in front of the Secret Garden wall at Ferncliff (see complete plant list below)

The question comes up every September in my garden. The meter-reader, oil delivery driver and countless guests have asked: “What’s that bright yellow shrub over there by the wall… The one covered with birds and red berries?” When I ask, “Have you heard of Lindera benzoin, North American spicebush?”, the answer is invariably ‘no’. And no matter how many times I make the introduction, it’s always surprising to me that this gorgeous shrub isn’t more widely known and used in the landscape. Spicebush’s season-spanning, informal beauty makes her the perfect choice for naturalizing along woodland boundaries and in countless other transitional situations. But as you can see from the photo above, this native plant also works beautifully in a mixed-border; with other trees, shrubs, bulbs and perennials.

Lindera benzoin, autumn leaf detail

The show begins in first weeks of April, when the spicebush’s lightly-fragrant, lemon-yellow blossoms begin to open on the dreariest of days. These early flowers are an important source of nectar to pollinating insects —including native and honey bees—and a welcome sight to my winter-weary eyes. The specimen pictured above — in front of the stone wall surrounding the Secret Garden— has developed a round, mounded shape in full sun (I prune very lightly after the early spring blossoms fade). Lindera benzoin will also tolerate light shade, and the groupings here at the edge of the native forest have developed a more open, but graceful habit. After the early flowers fade, attractive, blue-green foliage (the leaves have a delightfully spicy, masculine fragrance when crushed, and can be used to make tea, herbal sachets or potpourri) makes a fine backdrop for other players in front of the perennial border.

Lindera benzoin at Fercliff in late September (planted here with Juniperus chinensis ‘Sargentii’ and Ilex verticillata ‘Red Sprite’)

As pretty and uplifting as this shrub is when blossoming in April, come September, spicebush really turns things up a notch in the garden when its foliage shifts from cool green to brilliant, lemon-gold. The female plants (this species is dioecious and a male must be planted nearby for the female to produce fruit), with their bright red berries (edible/substitute for allspice), are especially fetching in autumn; attracting birds from the nearby forest by the dozen. Combinations with other showy, autumn shrubs and trees —such as bold red viburnum (particluarly V.bodnatense and V. trilobum), dogwood, witch hazel, and red vein enkianthus— are always gorgeous. And rich purple or deep-blue blossoms —including monkshood (Aconitum) and asters in autumn, and glory-of-the-snow (Chinodoxa), crocus and grape hyacinth (Muscari) in spring— make lovely, perennial and bulb pairings with spicebush on either end of the growing season as well. Conifers, particularly deep green hemlock (Tsuga canadensis) and blue spruce cultivars (Picea pungens) also provide a striking contrast to luminous Lindera benzoin, both in texture and color. And keep in mind the design possibilities of deep violet foliage when choosing a spot for spicebush. Dark, burgundy shrubs, including Physocarpus opulifolius ‘Diablo’, P. opufolius ’Summer Wine’ and Cotinus ‘Royal Purple’, really bring out the golden hues in Lindera benzoin; as do perennials like purple fountain grass (Pennisetum rubrum) and Sedum ‘Matrona’ or S. ‘Purple Emperor’. In a shadier situation, try spicebush in combination with the purple foliage of Heuchera cultiavars (like ‘Plum Pudding’ and ‘Palace Purple’) or perhaps Actaea racemosa (aka Cimicifuga racemosa ‘Hillside Black Beauty’ or ‘Brunette’).

Lindera benzoin provides a luminous, gold backdrop for other autumn colors (here with Viburnum bodnantense ‘Dawn’)

Hardy in zones 4-9, Lindera benzoin is a native of N. America from the north into Canada and on south to Florida; into midwestern Michigan and Kansas, and southwest to moderate climate zones of Texas. As a landscaping plant, spicebush is relatively trouble-free in the garden or naturalized settings; forming a mound-shaped shrub (6-12′ high and wide) when planted in a sunny location. In the shade the shrub tends to form a more open shape (a bit like Amelanchier); absolutely lovely, though subtle, when in bloom. Lindera benzoin prefers even soil-moisture (dry conditions make for a scruffy looking specimen) with cooling mulch about the root-zone (helpful to preserve even soil temperature and moisture)

Perhaps you’re already acquainted with lovely Lindera. If so, remember to pass on the good word. Mid to late fall is a great time to add shrubs to the landscape (see related post here). This native plant is an important part of our natural, North American habitat, and a significant source of food for insects (bees and butterfly larvae) and birds. But it seems to me that the spring blossoms, red fruit and glorious, golden, autumn color of Lindera benzoin provide all the promotional material any plant could ever need…

North American Native Spice Bush (Lindera benzoin) – Shown here at Ferncliff with Pennisetum alopecuroides ‘Hameln’ (and in the background Cornus kousa, Ilex verticillata and Juniperus chubebsus ‘Sargentii’, seed pod remnants of Rudbeckia. And to the left Fothergilla major ‘Mt Airy’ and various Sedum)

Lindera benzoin bloom Photo is via PIWO (CreativeCommons license Flickr)


10 2010