Pages

Monday, October 12, 2015

Classic Natural History I: Anna Bateson's botany

I've lately had a little bit more free time, having had my experiments burned (more burned in the Jerusalem fire after I wrote the blog post about the Rocky Fire) and having just submitted a manuscript I'd been working on. So I've decided to spend a few hours a week reading older natural history and ecology papers. I've been working through the 1800's in American Naturalist, Annals of Botany and Science Gossip - a wonderful popular magazine including observations of natural history, short articles and summaries of research. I've done this haphazardly, reading the table of contents to find interesting articles. I surely let many interesting ones through, but there is practically limitless material, so that is unavoidable. 

I'm going to try to highlight some of these papers - the astute observations, clever experimentation, often beautiful writing, and a little history, too. I probably would have left out the last piece, but several things - including Charley Eisemann's beautiful history/biography/natural history piece on Annette Braun, a forgotten but influential naturalist; Graham et al's the Essential Naturalist, and Bernd Heinrich's biography of his father - have inspired me over the past few years to think a bit more about the people and history behind old natural history.


Many also have beautiful illustrations (like this domestic hybrid pitcher plant). From M.C. Cooke's Freaks and Marvels of Plant Life (1882).

A few papers I found that seemed quite cool were those of Anna Bateson (1863-1928). She was sister to William Bateson, a famous botanist of the day. She worked at as an "assistant" in Cambridge's Balfour Biological Laboratory for woman students, closely with Darwin's son Francis and built upon Darwin's plant work herself. She helped found the Cambridge Women's Suffrage society in 1884

One thing I often appreciate about older papers is the lack of the standard paper formula (Intro, Methods, Results, Discussion), instead a more narrative style that presents data and observations where necessary in the story. Bateson's "The effect of cross fertilization on inconspicuous flowers" from Annals of Botany in 1888 is a really nicely laid out concise argument. She starts with Charles Darwin's observation that while many small flowers are selfing and not visited often by pollinators, it would be strange that they would still be open if they were completely selfing. 

Darwin did not do these experiments because of the "difficulty of [crossing] them". Bateson did this tedious job for three species (of three families!) and found clear outcrossing benefits in all. Her experimental prowess is obvious, as is her sense of experimental design ("it would have been a better method to have obtained the self-fertilized seeds by artificial fertilization also"). And her conclusion - that outcrossing is a benefit to even usually-selfing plants is certainly correct. 

Also from Cooke's book, where he explains the actions of plant tendrils, a phenomenon still being researched mechanistically.

Another clever experiment concerned geotropism. She and Francis Darwin hypothesized, based on prior theory, that a stem lying directly on the horizontal is the most stimulated to move. They note that this is actually harder to test than it might seem, as if you simply let a stem curl, it will be subjected to varying stimulus as it curls upward (if the hypothesis is correct). Cleverly, they came up with a method to expose plants to varying stimuli independent of their response, by pinning them down for two hours at a given angle (they use three: stem pointed 60 degrees up, 60 degrees down and horizontal). They then released all three treatments for an hour and measured the angle. They got quite clear data supporting their hypothesis. In both cabbage (n=36) and plantain (n = 148), horizontally-placed stems curved more intensely than either down-sloped or up-sloped stems. I don't know much about geotropism, so I can't actually comment on the lasting scientific value of this experiment, but it was an elegant and simple experiment (science fair? lab demonstration?). 

The last paper is more of a monograph and concerns irregular flowers (i.e. not radially symmetric). Anna and her brother William detail many examples of abnormalities in flowers. They suggest that irregular flowers must have evolved from regular ancestors (we know macroevolutionary patterns and part of the molecular basis for this now) and that the best way to study the possibly evolutionary pathway is to look at variation in flowers now, to see what variation evolution is acting on in the present.

Plate of floral mutants in Bateson and Bateson 1891.

They write very clearly about natural selection and macroevolution in the introduction, making clear difficulties with the lack of intermediate forms, determining descent, and the apparent lack of utility of intermediate forms of an organ (essentially Paley's watchmaker argument addressed by Dawkins). They even mention punctuated equilibrium versus gradualism "Supposing, then, that such a series of ancestors were before us, the matter to be determined would be the degree to which the series is continuous or discontinuous: that is to say whether the differences between any one member and its immediate successor are so small as to be imperceptible, or whether there are distinct and palpable difference between them; or whether they are sometimes small, and sometimes so great as to cause interruptions in the series and divide it into groups". They follow this with a nice metaphor of evolution as chemistry or physics. They fall into Gould's camp, clearly thinking that evolution proceeds with discontinuities ("the objections to supposing that the process of evolution of forms is discontinuous are derived, firstly, from the scarcity of observed instances of sudden and large variation,,, it is in the hope of dispelling [this] objection that the present observations are recorded") [1].

The crux of their careful observations of toadflax, speedwell, gladiolus, and Streptocarpus lie in the fact that they are characterizing mutants that show a phenotype of different regularity from the parent. Especially interesting are their findings of apparently radially symmetric speedwell (#19 in the plate) and varying symmetries in all the species examined. They conclude these detailed observations by pointing out that while gradualism may be common, mutations that fundamentally alter an essential feature of a species (regularity of the flower; or Lenski and lab's digestion of citrate by E. coli) do occur. They state "The facts now given, though few, are a contribution to such evidence and, in our judgement, are a sample of the kind of fact which is required to enable us to deal with the problems of descent". Given that we now know that during plant evolution, both to and from irregular flowers has occurred many times, it is likely that the Batesons' work was prescient, it was certainly detailed, well-written and well-reasoned (they present a section at the end detailing the many limitations of their observations that is nowadays hardly admitted in a question and answer session, let alone in the published paper!). 

I spent an enjoyable couple hours reading this papers and composing this post. I'd love to hear suggestions of other interesting papers, comments on these papers, and really anything else natural history. 



[1] This is of course, a sort of contrived analogy on my part, as they are taking a saltatory view - a mutant occurs in one generation in the Batesons' argument, though in my reading, they are taking a wider view in the introduction, even with the preceding "between one member and its immediate successor".

Thursday, September 3, 2015

Fire, transpiration, local hydrology and some very happy sunflowers

The Rocky fire swept through McLaughlin Reserve at the end of July. Nearly five weeks later, I resurveyed some sites that I went through the week after. The amount of life that had survived in the completely wrecked sites was astonishing, as was the quick resprouting of some plants (Rhamnus, Salix, Quercus, Vicia, Brassica, Asclepias, etc.). But the most surprising thing was the "winners" of the fire. I've walked columbine this seep many times a week during the past two summers. This time, I was struck by how large several serpentine sunflowers (Helianthus exilis) and tumbling orache (Atriplex rosea) had become.

Several stupendously super-sized serpentine sunflowers stoutly standing in foreground. A couple orache visible in the background.
Before the fire and all of last year, these were quite small plants, reaching maybe 1-2' tall with a couple dozen flowers. In many places, they end at 6-10" with just a few flowers. These plants were over 3' tall and each had a hundred or more flowers. What happened?

Last year there was a little bit of odd late-summer weather, with a few overcast cooler days (it is usually above 90 and not a cloud in the sky here). On those days, one very small seep that I had a columbine population in would fill up a couple tiny puddles that hadn't had water for months. After a couple times, I mentioned this to the reserve manager here and she pointed out that the plants around the seep don't transpire as much on cloudy days, so the water being put out by the seep was not being used up before it got to the ground. 

What transpires less than plants in overcast conditions? Dead plants. Right after the Rocky Fire, the seep with the sunflowers was flowing again big time (it is much larger and had much denser vegetation around it than the one that I could see the changes before). The amount of water in this seep now is greater than it's been since April or so. While the sunflowers and Atriplex are past the end of the visible water in the seep by a few dozen yards, it is still flowing belowground and these are pretty much the first plants that would be getting any of that water, as all plants upstream are fried.  

This section had been completely dry for months before the plants stopped sucking up all of the water flow. Also note all the greenery. That is resprouting of Aquilegia eximia, Stachys albens, Salix sp. and a few grasses and sedges (you can fire me as your naturalist if you'd like - I have no idea what species are here).  
This was an cool and unexpected - though completely logical - thing to find in the aftermath of the fire. I'm sure its been described before, but it was really eye-opening to me to see how much water those plants were transpiring and just how much influence this had on the hydrology and the success of other plants far below them (it seems like asymmetric resource competition - the manzanita and willows above were dictating the reproductive potential of the sunflowers below).

Something similar may have been happening to trigger this flowering of Mimulus guttatus, but I'm a bit puzzled, as this was in a strange location for that to occur and nothing else around it was doing particularly well. It was certainly a pleasant surprise to see some spring-like color at the end of the summer!
I'll write a longer post about the Jerusalem fire (more lost experiments... but not all!) and some other interesting observations that I've had during my last couple days of wanderings. But I've got more field work to do now. 

Dragonflies were hanging out in the seep like nothing had changed. I believe this is Aeshna walkeri (common last year here and with the same gestalt), though I didn't have my net with me to confirm and I wouldn't have wanted to disturb her egg-laying anyway (I'm a bleeding heart when it comes to dragonflies... and snakes... and beetles... and others). 


Tuesday, September 1, 2015

New paper: plant external chemical defenses!

When I came to grad school, I was convinced I'd be working on plant-caterpillar-parasitoid relationships, with a focus on plant chemistry or biocontrol. I wrote my NSF-GRFP on the artichoke plume moth and several of its parasitoids. I spent a few months looking for plume moth caterpillars on thistles (a scratchy job) with relatively little success, though not for lack of trying. My focus then shifted to a cute little butterfly, Brephidium exilis, with strange population dynamics and then parasitoid sex ratios. All of these failed (either through logistical problems or me half-assing them because they just weren't that interesting to me).

And then I happened onto Blitum (=Chenopodium) californicum at Bodega and my research took an unexpected turn. As I describe here, I was fascinated by the little fluid-filled pockets on leaf surfaces. I ran a number of small tests and found a defensive function of the bladders (probably one of many, many functions) and wrote it up and it was quickly published in Oecologia, a good journal. This being the very beginning of my second year of grad school (fall 2013), I was pretty jazzed. My committee, however, thought that I should be working on "the bigger picture". And so the ideas for this new paper on external plant defenses came about.

Writing this paper was WAY harder than I thought it was going to be. Instead of a formulaic paper, here's why I did the study (intro), here's how I did it (m&m's), here's what I found (results) and here's why its important (discussion), I was faced with a blank slate. I could write this however I wanted and that was a bit daunting. Primary and secondary school taught me how to write a coherent 3-5 paragraph essay, secondary school and college taught me how to write a term paper and college and grad school have taught me how to write a scientific paper, but no one taught me how to write a synthesis/idea/review paper. I'm glad I did it, though I think it will be a few years before I start on another paper like this.


This caterpillar (an unidentified pterophorid) lives on a plant (Hemizonia congesta) with lots of glandular trichomes, the factories of many external defensive chemicals. It blends in nicely with its "glandular trichomes". 
Taking Rick's lab motto, a Buckminster Fuller quote - "dare to be naive" - to heart, I started by thinking of what ecological differences would occur if a defensive plant chemical was situated on the plant surface instead of inside plant tissues. I came up with five basic differences between chemicals on the surface of plants (external chemical defenses: ECDs) and those inside plant tissues (internal chemical defenses: ICDs):

(1) they are in direct contact with the abiotic environment;
(2) they are not in direct contact with plant tissues apart from the cuticle;
(3) they are first contacted by the vast majority of interacting organisms;
(4) they may contact more than just the feeding and digestive parts of interacting organisms;
(5) they are secreted from specialized structures or cells (or derived from a secretion thereof).

As discussed in a prior post, glandular exudates are often sticky and can have cool tritrophic effects. Here is a mayfly (Ephemeroptera) stuck on serpentine columbine (Aquilegia eximia). 
I then took this list and delved into the literature, reading hundreds of papers on plant chemical defenses over a several month period (I cited 180 in the final paper, but probably skimmed or read abstracts of  twice that number). While external chemical defenses had not been formalized as a class, many wonderful studies had investigated plants with ECDs and I was able to find many examples both in terrestrial systems and in marine alga. I wrote up a massive tome - over 18,000 words - with carefully detailed natural history of many of the studied systems. Of course, this was not publishable, though I was proud of it (I like nothing more than to put cool natural history into an ecology/evolution framework). I worked and worked on cutting it down to its basics. In the process, I found more references and presented it at ESA last year, getting some more feedback. The process dragged on and I got more and more interested in doing experiments and less and less interested in this mammoth synthesis paper. I submitted it a couple times in various stages of cutting and was basically told it was too long. So after this past field season, I sat down for a couple weeks with no other distractions and made it into a far more focused paper, which I submitted to Biological Reviews, as it was still a bit long for most other journals. Fortunately, it was accepted with helpful reviews and after tossing a few minor points back and forth with the editor, it is now out for you to read!

Without getting into the specifics (you can read them in the paper, if you so choose), I found that many chemicals are on plant surfaces, many of these chemicals are defensive, and these may be systematically different from internal chemical defenses in the ways I hypothesized. This paper is important for three reasons: 1) hundreds of papers are published on plant chemistry and plant chemical ecology each year, but it is ecologically important where certain chemicals are located; 2) we have a rich body of theory on plant chemical defenses, but some parts of it are rather untested, and ECDs may allow some tests of certain theories (e.g. optimal defense theory) and; 3) many important crop plants have external defenses, which are easily manipulable in many cases, and it may be useful to think about them in this way to come up with better pest management schemes.

I'm really curious about how this paper and this new classification scheme is received. Am I just cluttering the literature with new terms, or are these ecological differences informative and useful? We will see!

Castilleja minor, a species of paintbrush and a hemiparasite, has really cool oily exudates. The pictured caterpillar, possibly an Autographa (?) species, seems undeterred, though it does mostly eat the insides of the flowers and fruit, which may avoid the exudates. 

Sunday, August 9, 2015

Oops, my field site disappeared: lessons learned from the Rocky Fire

Last week, on the 29th, I was coming back in after a day in the field at the UC-Davis McLaughlin Reserve (in Lake County, CA) where I do all my work. I was setting up some insects in containers in the building when some one from next door came over to point out a smoke plume rising NW of the reserve.

I wonder if this is the first photo of the Rocky Fire... it was taken at either 4:01 PM, Cal Fire says it started at 3:29, a few miles NW of the reserve. 
Within a few minutes, it was obvious that this wasn't going to be like the other, smaller fires that were put out quickly the week before in the same area. I continued doing my work and made dinner. I wasn't particularly concerned, since the wind was pushing towards the fire and the plume was making its way away. By nightfall, it got worse, and the wind began to shift.

7:57 PM and the smoke plume still moving away from us.  
At this time, I went next door to the mining building to hang out with the safety guy there, who was on site in case this caused any problems for them. By 10ish, the power had gone out, the wind had come around and there was smoke and a small amount of ash falling. By 11, CalFire had shown up and told us it had jumped the road and that we were going to be evacuated soon. I packed up a few clothes, my bug nets, computer and a little bit of food and was on the road by midnight and back in Davis a little before 3 AM (nearly hitting a deer in the process). I fully expected to be back in a day or two. I had planned to stay there for a couple weeks - my longest continuous trip of the summer - as both the tarweeds and the columbines are in the middle of their season in late July/early August.

Navarretia mellita, the subject of one of my experiments, which was going along swimmingly before I left. 
After the evacuation and my near deer miss, I was running on a bit of adrenaline... I got to sleep by 4 AM or so and was up again by seven. And I spent the better part of the following week that I was evacuated refreshing the CalFire website as the fire grew in waves until nearly 70,000 acres (that is ~110 square miles). My sites all lay pretty much on the fire perimeter - I had no idea what to expect until I got back, as I knew that fires burned patchily.

Doing small-scale insect-plant interactions, I do my experiments on a plant-scale - manipulating traits of one plant, and I mostly work on annuals and all on a yearly basis (which means I can't do a pre-/post-fire comparison). I do many experiments each season - this year I was running 7 at the time of the fire - all in the northern and western parts of the reserve, where the fire was most intense. So my heart was racing the whole trip back, when I was allowed in on Thursday (the 6th - over a week after evacuation). I dropped some refrigerated stuff off and quickly hurried out to my sites...

This is the wet meadow where my recently published experiment took place and where I had another experiment going this year. 
As I drove in to my columbine experiment, I knew it wasn't going to be a pretty sight. You can still see a streambed on the left side. Surrounding it was a nice population of serpentine columbine (Aquilegia eximia), hedge-nettle (Stachys albens) and common monkeyflower (Mimulus guttatus) with a scattered coffeeberrry (Rhamnus sp.) and willow (Salix sp.), bordered by THICK chaparral (manzanitas, oaks, chamise, etc.). I did find remnants of the experiment...

I should have bought the pin flags rated for raging-wildfire temperatures. Next time. 
My next experiment was through a tiny circuitous trail which I had carefully machete hacked earlier in the season through manzanita and cypress. It involved going over and under a number of logs and around small breaks in the chaparral. Yesterday I could walk (and see) in a straight line through a whole lot of nothing. All I found was a tiny bit of melted flagging tape, attached to a columbine stalk that had somehow escaped total incineration...

Based on its location (and most of my landmark shrubs were gone), I think this was control #50. It formerly was under a manzanita. I found it in the middle of a large, barren field.  

All was not lost, however! My next project was a huge set of experiments examining defensive induction in a tarweed, Hemizonia congesta (this specific epitaph is accurate, at least for me). Fire fighters had made a dozer line through the upper end of this field between two roads. The flames reached the two roads and the firebreak, but fortunately never jumped and my site (containing 250 plants which I had been following for months), ~200 meters beyond, remained intact. I was a bit worried that perhaps the insects would have been affected, but the insect communities seemed normal in abundance and identity.

My site is on the middle hump in the mid-ground. You can see the sparse vegetation on those serpentine barrens compared to the field of Avena in the non-serpentine areas. 
The grasslands were wild to walk around. Grass fires don't burn as hot nor for as long as chaparral fires, so some things survived. Not among those surviving were the rabbit-poop looking burnt star thistle flowers and fruit.
 
It burned the spines right off the thistle flowers. And it looked like most hadn't seeded... hooray!
The living stuff on the right is a variety of tarweeds (Hemizonia, Holocarpha and Calycedinia spp.) growing on a serpentine barren (low biomass). The burned area on the left was Avena and star thistle and had much higher biomass and apparently burns better. 
Like the wicked witch of the west when confronted with water, milkweeds (this is Asclepias eriocarpa) apparently just melt in the face of fire. 

Not all the milkeeds melted, fortunately for this large monarch caterpillar (and the orange oleander aphids out of focus in the foreground). There were a bunch on a small surviving patch of Asclepias fascicularis which was no more than 2 meters from completely scorched earth. I wonder whether they emigrated here from melted plants or if they were all on the one patch to begin with.
The grassy areas had tons of Mourning Doves. More than I've ever seen at one time in my life. Did they group up after the fire and emigrate right to my field site? I don't have a clue. I usually see them near Croton (Eremocarpus) setigerus, but that's not around this site - I wonder if they were eating burned thistle heads or other seeds exposed by the burning of all the grass.

The patchiness of the fire on a microscale was crazy. Here a small patch of seeding Mimulus nudatus (a rare California endemic found only in serpentine soils in a small part of the northern coast range) stands amidst a scorched landscape. 
Another set of experiments I had were also very close to a burned area, but they too, were spared. I was studying the ecology of two sticky species: Navarretia mellita and Madia elegans. Both are weedy species that love disturbance. There is an old road above the center that is drive-able, but rarely driven and hosts nice populations of both species that like the roadside disturbance. The Navarretia experiment was pretty much fine, being about 5 yards from the road. In the couple weeks that I hadn't checked it, some of the seeds had dehisced, but I had final inflorescence number for all the plants, which is enough of a fitness proxy for my purposes.

Big flags, little tiny plants.
The tarweed (Madia elegans), on the other hand, suffered a little bit. During the fire, trucks must have driven by that site hundreds and hundreds of times... I was there for the afternoon yesterday and had 4 or 5 cars drive by twice each (it is a dead-end) - and that was long after the fire was out in that section. Tarweeds are sticky and I was manipulating the amount of insects they caught (following up on Billy and Ian's Madia study and my columbine study). Most of the plants were within a yard of the road edge (non were on the road - none got hit), but with the hundreds of vehicle passes the amount of dirt kicked up and subsequently caught by the tarweeds was crazy. The treatments - varying amounts of dead fruit flies - were sort-of intact, but redoing the treatments was a major trial, as the fruit flies wouldn't stick. This will get better as they grow and they ought to flower for another month or so, so perhaps this won't be a complete wash... we'll see.

Its hard to see in this picture, but pretty much every glandular trichome on the plant had dust stuck to it, rendering it pretty much completely unsticky. 
The last experiment, a manzanita fruit manipulation, had pretty much been doomed from the get-go. I started the experiment early in the season, when the plants thought they had lots of water, but soon after, they aborted all the fruit I had in the experiment. So I moved to a new site, on the edge of a pond, where the shrubs were a little bit happier, but I started it too late (as I was still nursing the first try along a little bit). The fire left only one of those manzanitas standing at all as it whipped around the pond. Not a huge loss, though it would have been nice to get the last set of data.

A dead deer in the pond that the manzanitas were next to. I don't know for sure that this was fire related, but it seems likely as the chaparral up to this pond on three sides was burned completely for hundreds and hundreds of meters. 
 In the pond, besides the dead deer pictured above, life seemed to go on fine. The tule and cattails were intact, as good, water-filled greenery should be. Pied-billed grebes continued to feed streaky little babies and coot made all their funny noises. I finally saw the first Ruddy Duck baby of the year - in years past there have been quite a few in this pond and this year there were quite a few pairs, but only one duckling seems to have come out. A Gadwall nest that I found a few weeks back should have hatched (or been preyed upon by coyotes, raccoons, etc., by now) and a few rather large babies were around the pond, along with the first Green-winged Teal of the season. Tiger beetles ran on the shores and dragonflies flitted by, as if nothing had happened.

I'm not sure where this jackrabbit fled during the fire, but he's a survivor for sure - there wasn't much unparched in the area that I found him. There were a good number of these around - and strikingly, in a lone patch of Garrya, with literally nothing for hundreds of yards around, a chipmunk scolded me!
Other folks lost experiments as well. This was a bird exclosure, under which was a chamise that had been monitored for years. 
The amount of life around, even in burned areas just a week later was astounding. While exploring, I heard a pair of Rufous-Crowned Sparrows chipping from a couple mostly demolished manzanitas along a completely devegetated streambed. They popped out to check me out - I suspect that most territorial animals are dealing with a lot of stragglers coming by. I had a secondhand report of a mountain lion wandering down a road near fire crews in the middle of the day - not a typical behavior. While watching sandpipers, I heard a barking, like that of a large dog coming from near where my truck was parked. Thinking it might be a lost dog displaced by the fire, I headed towards it. As I neared the truck, on a rock above it was a coyote, looking down at me and barking like hell. As I fumbled in my backpack for my camera, he ducked behind the rock and continued berating me until I left.

Walking through dense manzanita chaparral is miserable. Walking through the same area now is quite easy.

Though it makes you quite dirty. This was after only about 10 minutes. After an afternoon of hiking around, I looked like a coal miner.
For a number of reasons, I spend a bit of time looking at spiders: they are important predators on many plants, I've worked on crab spider behavior, and much of the Bahamian island research revolves around them. One of the first signs of life in the fire area was funnel web spider (Agelenidae) webs, which are a thick mat of webbing with hole the size of a nickel or so (like a funnel, as the name suggests). There were tons of them on top of the blacked dirt and vegetation.

A nice clean, fresh, funnel web on top of blackened soil. 
In contrast, in non-burned areas, the webs were messy with ash that was clearly flying in large quantities with the fire nearby. I wondered why the spiders hadn't spun a new web or cleaned it out. I suspect that the reason has to do with how costly spider silk is to the spider. Being made of protein and laid out carefully, it is both nutritionally costly and time-intensive to make a web. Many spiders eat their webs if they take them down and there is even a group of parasitic spiders which eat the webs that other spiders make (!!!).

A web with lots of entrapped ash. I think it is a theridiid, but I didn't look too closely. All the webs were covered like this.
Pocket gophers also survived, with fresh diggings in the 5 or so days since the fire passed through this area. I just saw my first pocket gopher a few weeks ago, while being acquainted with their diggings for years. They have really, really weird ears.

Its been a really interesting time to look at the natural history of this area. The next few years, while I continue my phd, will also be an interesting time of watching fire-following plants, resprouters and who knows what else.

The fire opened up previously hidden scenes from dense chaparral, like this midden. I guess this was from when there was a nearby shale quarry operating, but I'm not sure. Those beer cans look old...
AND THEN...

I wrote most of this the night of 8/8/15. About 4 PM today (8/9/15), another call came on the radio about a smoke plume. I hurried outside and shit... another BIG fire, within a couple miles, this time SW of the station. This one has been termed the Jerusalem fire. I hurried and collected some seeds for a friend and reconned some badly dozered sections in the SE portion of the reserve.

Jerusalem fire, ~4:30 PM, 8/9/15. If the twittosphere is to be believed, those two plumes are from two separate arson fires.
These dozer lines are ridiculous. There are at least 4  (and a road) between this particular one and anywhere the Rocky fire actually burned. They tore the shit out of some really nice oak woodland habitat and compacted soil, etc. 
Fire haze does produce extremely beautiful light.

This charred live oak (?) leaf was one of many which rained down during my hike... the fire was 3-5 miles away at this point.

Like ecologists, firefighters seem to like to put flagging tape on anything interesting. Here on abandoned machinery. Its also on gates, fences, various poles, etc. 

A constant part of the wildlife now, these big birds are really thirsty, sometimes drinking 3,000 gallons every few minutes. I'm getting better at my identification of these. I think this is a Boeing 234 "Chinook", but these two rotor helicopters seem almost as confusing as empid flycatchers... field guide.here
We'll see how this one pans out... I'm not particularly worried for my experiments now. If they burn, they burn but there is a lot of burned area between this one and them (it is continuous, but the fire would need to turn a couple different ways before it got to anything).

The pond this CH-47 just refilled from is part of the complex where the field component of this paper took place. 

I did learn some field season lessons, as well.

Things I will do differently next summer:

1) Space my experiments out farther! The farther apart they are, the more likely a fire line will go between them in case something like this happens again.
2) Put them a little farther back from roads (this also would protect against accidental drive-overs).
3) Put them in a matrix of previously burned areas. Its hard to reburn the same areas two years in a row (though the Wragg fire managed that this year in Yolo/Solano counties!). That will allow a little extra safety.

And finally - while I lost some work (a couple months on a couple projects), I'll certainly be able to repeat those next year and I'll get a couple completed experiments from the seaon. Thankfully, I didn't lose my house, my pets, my vehicles or my livelihood - others did.

A lone manzanita looks out over a burned land. The road you can see in the back right is Roundtop road, in Knoxville Recreation area. It would be a good place to check this out from (but do not, under any circumstances, camp in the campground there). I guess the area to the right all has already/will burn in the Jerusalem fire, too. 

Wednesday, July 22, 2015

Sticky plant attraction, a new paper

I could not possibly do as good a job as the summary of this paper written by Elizabeth Preston, here, so I'll first tell the backstory - and when it comes out, I'll detail another cool part of it (which is not in the preprint version - instead buried in the appendices).

Heliothis phloxiphaga eating a flower bud of Aquilegia eximia, the serpentine or sticky columbine. Lake County, CA. 
Last summer, I spent most of my time studying Trichostema laxum, which I've written about in a previous post. I was trying to test my hypothesis that external chemical defenses are easily washed away by rain (which may be driving the pattern that few are found in wet areas) and spent countless hours doing various pieces of this - observing pollinators (the volatiles washed off might affect pollination positively or negatively), counting insects, leaves, buds, flowers and seeds (which can be done in situ!) and by July, the drought and some jackrabbits made this experiment look rather grim. I still haven't brought myself to analyze these data, as it ended so depressingly...

As the floral color polymorphism was not in the experimental population, I didn't notice it until the end of the summer, and gathered some, but not enough, data on it. Lake County, CA. 
I was getting a little frustrated and I wandered around, naturalizing, which is always a remedy for frustration (to me at least). I came upon a columbine - Aquilegia eximia - which I instantly knew held some potential for cool experiments. The first thing I noticed was that it was extremely sticky and covered in dead insects and the second was that it had a bunch of predators on it. I immediately thought to Billy Krimmel and Ian Pearse's cool paper on tarweeds (doi:10.1111/ele.12032) , in which they demonstrated that the dead insects provided food for predators, which protected the plant from herbivores. I figured initially that I would simply test this in another system.

A Hoplinus nymph (probably the most important predator in the system) approaches an
entrapped fly.
Because I was out in the field without access to a genetics lab to get dead flies, I couldn't replicate their design - where they added dead fruit flies to plants to supplement carrion - so instead I removed all the carrion from half of my 50 plants, hypothesizing that I would get a decrease in predators and an increase in herbivory (which we did!). I also thought hard about what else to test to add to Billy and Ian's work. I thought that, perhaps, it would be interesting to test whether the plants attracted the various entrapped insects (mostly small flies, wasps and beetles) somehow. Lots of plants attract insects - pollinators are the most obvious, but volatile signals attract predators, other herbivores and even birds (doi: 10.1111/ele.12177). Having petri dishes, plastic mesh and tanglefoot in my field kit - I made little sticky traps, with a sticky mesh top and a petri dish bottom and I put either columbine stems and leaves (a very small amount) or nothing in them. Collecting them 24 hours later, I found that the dishes with columbine had higher insects than the empty ones (which would demonstrate the ambient rate of insects landing on these traps). The trapped insects were also little flies, wasps and beetles, just like on the plants themselves.

Dead Hymenoptera on columbine (I may be giving up entomologist credentials, but I am not sure whether it is a wasp or an ant alate).

So this became a story - perhaps logically - that the plants were somehow attracting insects to kill and feed to the beneficial predators on their surfaces (retaining their services). I presented this work in a talk at a little student conference at Davis during recruitment weekend and played with several ways to frame the story. The first was to be rather dry - columbines attract insects and control a tritrophic defense (or something along those lines). Instead, I thought long and hard about trying to make a metaphor (socialism - a worker's paradise for the predatory bugs or a Roman bread and circus type thing, but they didn't really work) and while I don't remember how I came up with this - I settled on the sirens, figures of classical mythology who lured sailors to their deaths. I therefore framed it as these poor insects - innocent sailors of the California air - are somehow drawn to their deaths on the columbines. Of course, the columbines put the insects to good use in their defense, leaving open the question - which I am sure classical mythologists lose much sleep over - what did the sirens do with their collection of dead sailors?

Serpentine columbines in flower. Lake County, CA. 
Read more here!

Eric F. LoPresti, Ian Seth Pearse, and Grace K. Charles In press. The siren song of a sticky plant: columbines provision mutualist arthropods by attracting and killing passerby insects. Ecology. http://dx.doi.org/10.1890/15-0342.1