Castilleja miniata, a very common paintbrush species in Western North America

Anyone who has spent much time in the Western U.S. is probably familiar with one of our most attractive wildflowers – Castilleja, or Indian paint brush. Blooming riotously in the summer, from deserts to alpine meadows, the nearly 200 species in this genus (many endemic to North America) put on quite a display – a riot of reds, oranges, yellows, pinks, and purples. Despite being maniacally difficult to tell some of the species apart, Indian paintbrush is one of my personal favorite wildflowers, and not just for it’s breathtaking colors.

There are a couple interesting things about Castilleja. First off, the colorful blooms that make it so remarkable are not actually the flowers. They are the leafy bracts surrounding the very inconspicuous and uninteresting greenish white flowers at the very tip. Much like poinsettia, all the action is in the specially formed leaves. You can kind of see this once you know what to look for, as the color sort of shades back to green as you move down the stem.

Haustorium. Note how it goes through the tissue but doesn't puncture the cells.

Another thing you may or may not notice about Castilleja is that you almost never see it alone. Some wildflowers like mountain bluebells or little sunflower form huge monolithic stands, but Indian paintbrush is almost always scattered through an area with other plants. The reason for this is that, although it looks just like any other green forb to the naked eye, Castilleja is actually parasitic on other plants. In fact, it comes from an entire family of plant-on-plant parasites, Orobanchaceae. Although levels of parasitism range greatly in this family, they all have a defining characteristic: haustoria. Haustoria are specialized roots that drill into the roots of other plants for the purpose of stealing their resources.

Of the parasitic plants found in this family, Castilleja is actually a fairly mild parasite, known as a root hemiparasite. Since they have fairly normal green foliage, they can photosynthesize on their own. But they get a huge boost in fitness from stealing water and other essential minerals from a host plant. This may be an adaptation to places where resources, like water, are limited, the growing season is short, or the soil is poor.  And while in the wild Castilleja is almost never found without a host, they can technically survive on their own, although they are much less robust in every way if grown in isolation. Castilleja also does not kill its host plant, although it often does take a toll on its fitness and growth.

Castilleja species are generalist parasites. Although certain species do much better with and seem to “prefer” particular host species, they will usually take whatever they can get. Because the species available to them may vary greatly and because they inhabit such a wide range of ecosystems, it’s to their benefit to be flexible and work with what is around – if you’re too picky you might find yourself with no host at all. In dry areas, sagebrush is a common host plant to desert species of paintbrush. In other places, lupine species (another large genus of the western U.S.  found in a range of habitats) are one of the most common hosts. In fact, Castilleja plants that are able to latch on to lupine as a host plant may be very  lucky individuals.

Red paintbrush grooving on lupine; a common sight in the summer.

As a member of the bean family, lupines have a symbiotic relationship with nitrogen-fixing bacteria and any plant parasitizing them is going to get increased access to nitrogen. Studies have shown that Castilleja using lupines as host experience better growth, increased reproduction, and increased pollen output. Lupines may even offer some protection from herbivory to Castilleja, as along with nutrients parasites also receive the alkaloid lupinine, which is toxic and bitter to animals. This protection may be conferred to the Castilleja, although studies have shown mixed results in whether having lupine as a host actually does decrease herbivory on Indian paintbrush or not. Either way, it’s clear there are big benefits to taking advantage of lupine, and in my area it’s not uncommon to see meadows full of almost exclusively lupine and paintbrush.

Castilleja, along with other root hemiparasites, can actually have a surprisingly large effect on community structure as a whole. Introduction of a species like this can shift the entire dynamic by helping or hurting various other competitors for resources. Say you have a plant community that is dominated by one species of herbaceous plant. There is another species present, but it just can’t compete and is barely hanging on. Now, in comes a root hemiparasite like Castilleja. It gets big benefits from parasitizing the dominant species and not much from the secondary species. But in the process of parasitizing the dominant species it greatly reduces that species’ fitness. Suddenly, the secondary species can compete! This can lead to a community going from a virtual monoculture to either a stable system with the three species (parasite, dominant, and secondary) existing in roughly equal proportions, or a constantly fluctuating system where one species becomes extremely successful for awhile before the other takes over in a repeated fight for dominance.

Castilleja rehexifolia, a pretty pink paintbrush

In addition, if the root hemiparasite does better on the less dominant species, it may actual confer a competitive advantage on the secondary species and help it to increase its range against the dominant species. While the secondary species alone may have no hope of out-competing the dominant species for limited resources, in combination with Castilleja or another hemiparasite they together may succeed in elbowing out the normally successful dominant and either sharing or completely excluding it from the system it previously ruled.

As you can see, Castilleja and other root hemiparasites are forces to be reckoned with. But there is still much we don’t know about them. Are there other ways they confer benefits to their hosts? Are some species evolving to be host-specific? How much do they actually take from their hosts? And is their color (variable within a species and location) dependent on the nutrients and minerals they receive from the host plant or is there another factor? The complicated systems in which they exist and the huge variation among species make any questions about this genus difficult to answer definitively.

References:

Smith, D. (2000). The Population Dynamics and Community Ecology of Root Hemiparasitic Plants. The American naturalist, 155(1), 13-23. doi: 10.1086/303294.

Adler, L. S. (2003). Host Species Affects Herbivory, Pollination, and Reproduction in Experiments With Parasitic Castilleja. Ecology, 84(8), 2083-2091. doi: 10.1890/02-0542.

I recently read two books back-to-back that were so similar in premise, size, and even layout that I couldn’t help but compare them. Both books were dedicated in their entirety to a single of type of small mammal, written by scientists who had studied them extensively, and both promised an intimate look at not just the animal in question but our longstanding relationship with it. The two books were “The Hedgehog’s Dilemma” by Hugh Warwick and “The Story of Rats” by S. Anthony Barnett. Unfortunately, the similarities end as soon as one begins to read. The books could not be more different in style, attitude, and, I dare say, quality.

“The Story of Rats” nearly lost me prior to opening with the subtitle: “Their impact on us, and our impact on them”. While I am used to, and even guilty of, the egregious misuse of the word “impact”, it was a bit shocking to find such poor grammar so brazenly splashed across the cover of what one hopes will be an intelligent book. Nevertheless, I soldiered on, hoping to learn more about this fascinating rodent whose destiny is so closely entwined with our own.

Unfortunately, I was disappointed. The book reads as if the author’s publisher said to him one day, “Hey, you study rats, right? How about whipping us up a little book about ‘em?” and the author went home and wrote down everything he knew about his subjects over the weekend and presented it as a manuscript on Monday. Which, if you read between the lines of the preface, may not be far from the truth. Although I am sure the author is indeed an expert on rats, I spotted enough casual mistakes to make it clear that he was drawing primarily from his personal knowledge with little fact checking (stating rats were eating corn in Europe prior to the date of European discovery of the New World and inaccurately reporting Ring Around the Rosie as a reference to the plague). Small mistakes in what I do know make me wary of accepting the author’s authority on what I don’t.

At no point does the author actually define what a rat is or isn’t, although he mentions several species of rats around the world and that some are not “true rats”; yet he never tells us what makes a true rat. Unsurprisingly, most of the book is devoted to the brown rat, Rattus norvegicus, and most of what we learn in the first couple chapters is nothing that anyone who watched the “Your Friend, The Rat” Pixar short on the DVD of Ratatouille didn’t already know. Once he has dispensed with the history, he goes on to he use of rats in research, their intelligence, habits, and function as disease vectors, sometimes talking down to his audience and at other times shooting over their heads.

The writing is mostly dry, and rather lazy, and the author shows a remarkable lack of affection for his subjects. He seems to take a very mechanistic view of animal life, which bothers me, believing that almost every behavior rats exhibit is pure instinct, and dismissing their intelligence out of hand. He even says at once point, “if rats think at all…”. I find that model of scientific inquiry extremely outdated given what we know of animal intelligence today. He also is dismissive of the degree to which the study of rats can be related to human behavior, which felt like it was based on pure bias (we aren’t like them) rather than actual science. Overall, I found the book, though short, extremely tedious and unhelpful, and in some places it downright pissed me off. It would have been better titled “Some Stories About Some Rats: Why They’ve Been a Pain In Our Ass for 8,000 years”.

“The Hedgehog’s Dilemma: A Tale of Obsession, Nostalgia, and the World’s Most Charming Mammal” is almost the complete opposite in every way. From the subtitle on the author makes no secret of his adoration for the prickly little things. The writing is personal, witty, honest, funny, and engaging. From his earliest adventures as a undergrad counting hedgehogs on a remote isle in the North Sea to the current rage in America for African hedgehogs as pets, the author recounts the story of our relationship with hedgehogs with sound science as well as sound journalism. Although he admits freely to loving hedgehogs, he also attempts to take an honest scientific look at their effects on the environment and their role in the ecosystem, including in places they have been introduced.

I found this book extremely interesting, as it was written from a British perspective. In the U.K. hedgehogs are as common as squirrels are in my east coast home, and hedgehogs as well as “carers” (enthusiasts who taken in orphaned and injured hedgehogs and nurse them back to health before releasing them) are simply everywhere. To me, who grew up in a place with no hedgehogs but reading a lot of British children’s fiction, hedgehogs are either exotic creatures or magical characters who talk in fairy tales. It boggles my mind that they are such a ubiquitous part of British culture.

It is difficult not to adopt some of the author’s hoggy enthusiasm, and the book does not disappoint the sudden thirst to know more, which it itself inspires. We learn about the evolution, natural history, anthropology, and cultural effects of the hedgehog, as well as its unique personality and the even more unique personalities of those who care for them. The book is at once intensely personal and scientifically rigorous. My only complaint with the writing is a niggle – he tends to drop people’s names into the text without properly introducing who they are and where they have come from. Other than that, this book was a gem – and it gets bonus points for the section at the end about how to make your garden more hedgehog-friendly.

What, July already? Happy Canada Day everyone! And happy Independence Day on Monday! I hope everyone’s got fun plans for the weekend. Since it’s supposed to hit 103 F here on Sunday, mine include “finding a cold lake above 10,000 ft and staying there”. Enjoy the linkfest as you run out the clock before the holiday weekend.

Ecology/Evolution Links:

1: This is what we get for decades of fire suppression. The mega-fires now raging in the southwestern U.S. are so large and intense they may cause permanent damage to the ecosystem, despite it normally being considered a fire-adapted system. Small fires rejuvenate, but ones like these only devastate  (Wired Science).

2: Crows, already one of the animals strongly in the running to take over the planet from us (along with octopi, dolphins, and ants), not only have great memories but they can transfer their knowledge of danger to other crows who haven’t experienced them. Bird telepathy? Let’s hope not, but however they do it, it’s wicked cool (Global Animal).

3: Let’s hear it for the owls! The National Fish and Wildlife Service this week, after years of waiting, finally published recovery plans for both the Northern Spotted Owl and the Mexican Spotted Owl. That is, if the Mexican Spotted Owl can survive in the smoldering wreckage that is now much of its territory (NY Times).

4: Sing me home! A detailed explanation of population structure and fluctuations of  southern right whales over the past few centuries. No one knows for sure how many there are now, but the good news is they seem to be doing fairly well (Deep Blue Home).

5: Scientists are putting together an advertising campaign aimed at monkeys. No, it’s not to get them to volunteer for lab experiments. Having taught them to use money, they now hope associating a product with sex (female monkeybits) and dominance (alpha males) will make them chose that product over others. My question is, will female and male monkeys be equally susceptible to the same ads? (io9)

General Science Links:

1: More casualties of on-going budget crises – public health. Due to a government shutdown, Minnesota will lose many services, including it’s incredible public health unit which does a Swedish-quality job of stopping foodborne illnesses before they spread. Because people getting sick from MN food products will help the economy… (Superbug).

2: Remember kids, there’s no such thing as “chemical-free”. Period. If you are chemical-free, see your doctor as you may have become a ghost (Speakeasy Science).

3: As a culture and as a species we are obsessed with things we can’t explain, often lumped together under the banner of the “paranormal”. But why? Do our brains hold an answer? Salon presents an interesting and vaguely science-y discussion (Salon).

4: Autism, ever more common in this country, is often spoken of synonymously with an inability to empathize. But is that really true, or are are we confusing an inability to understand signals with a lack of feeling? (Thinking Autism Guide)

5: Matter is so awesome! Japanese researchers have developed a new alloy that can return to its original shape at a very wide range of temperatures. Apparently we already had ones that could do at a narrower range. Kinda puts some of those Roswell reports in perspective (PhysOrg).

Because-I-Feel-Like-It Links:

1: A statistical exercise of dubious value/accuracy but limitless fun calculates the number of things you are more likely to do than intentionally click on a banner ad. Better not tell that to the advertiser, though, or our whole internet economy could come crashing down (The Atlantic).

2: Misdirection – sometimes it’s the only way (xkcd).

3: Stephen Colbert makes mockery of campaign finance laws even more realer by forming his own Super PAC ostensibly to use Viacom money to run campaign ads in this election. Funny joke or brilliantly sneaky political plot? I guess we’re find out in 2012 (AV Club).

4: Dan Savage and others make a case for (some) non-monogamy. Can’t say I totally agree with him, but I can’t really judge other peoples relationships, and its a fascinating article nonetheless. Plus I adore the guy (NY Times).

5: An Anabaptist makes a compelling case for not celebrating Independence Day if you’re a Christian or a pacifist. Or both. Uncomfortably thought provoking (Pangea Blog).

And a new section wherein I tell you what to do with your weekend:

Make: An easy and impressive no-bake raspberry cheesecake. Follow this recipe, but use chocolate wafers for the crust instead of regular grahams, then top with fresh raspberries. Or a mix of raspberries and blueberries for a patriotic theme. Great to bring to cookouts this weekend.

Drink: Polygamy Porter, a Utah favorite. With a smooth taste and the tagline “Why have just one?”, it’s hard to resist. If you can’t buy it in your area, you can probably order it online (depending on your state) or pester your local store to stock it. Got wives? Get beer.

View: The night sky holds a lot of excitement in July. Mercury will be the first planet out, but we should also be able to see Venus, Saturn, and Titan with the naked eye.

See: Nothing! No good movies are coming out this weekend unless you’re in the vicinity of a showing of the limited release comedy “Terri“. If not and if you’ve already seen the brilliant Super 8, then go read Slate’s review of Transformers 3, realize you’ve dodged a bullet, and then rent the extremely underrated and frighteningly  fitting cult comedy Idiocracy and reflect upon how the former relates to the latter…

Go: Somewhere cool! It’s gonna be varying degrees of scorching across the country this weekend, and all the major lakeshores and beaches are likely to be packed. I recommend backpacking Utah’s Highline Trail, which only just finished melting out after an insane amount of snowfall this winter. Rolling terrain keeps you at a cool 10,500-13,000 feet with plenty of coyotes and mountain goats for company.

Anyways, on to our selection today. Whether you will enjoy “A Rum Affair: A True Story of Botanical Fraud” by Karl Sabbaugh probably depends greatly on how much of a plant or history nerd you are. In brief, the book is essentially a journalistic investigation of an incident in England in the early/mid 1900′s in which a distinguished professor of botany, John Heslop Harrison, was accused by John Raven (an amateur, but respected, plant enthusiast) of sowing rare species of sedges and other plants on the Scottish Island of Rum and then claiming to have found them growing there naturally, for the purposes of supporting his pet theory regarding the timing and extent of the last glaciation. Because Harrison was so respected and there was no way to prove the accusations, the papers regarding it were sealed and hidden away in the dusty records of Newcastle, nearly forgotten.

The author investigates the accusations, as well as all the incidents surrounding them and the lives and careers of the two major players, the professor and the accuser.  Although it is clear from the get-go (and the title itself, really) that the author believes the accusations of fraud to be true, he makes a fairly convincing and rational case for the guilt of the professor  (at least to this reader), without completely dismissing the value of Harrison’s other work and contributions to botany and natural history.

Although the book is highly historical in nature and Sabbaugh is not a botanist, the plants and the field of botany at the time get a very good going over, with detailed explanations of the fraud and the species involved. His lack of expertise is an asset here, as he does not shoot over the lay reader’s head with technical jargon but labors to explain the case and the science as it was explained to him. He also frames some of the conflict as a class struggle between the profession of humble origins and the privileged, talented amateur, which sheds a different light on the accusations and garners sympathy for the seemingly-insecure Harrison (although Raven is generally the more likable character). At times the writing is a bit dry and repetitive, but it is liberally sprinkled with wry humor and engaging anecdotes of those he is writing about and of his own experiences during the research process.

Although the basic information of the case is summed up nearly from page 1, if you are interested in the more esoteric details I feel the rest of the book is worth a read. This is a case that will never truly be solved; the evidence against Harrison is damning but by no means conclusive. But reading about it in detail not only provides an interesting glimpse into the world of British botany in the time period surrounding the second World War, but it also provides a setting for a discussion of larger issues regarding scientific ethics, verifiability, class discrimination, and the seeming immunity from accountability of respected authority figures in the scientific community.

I recommend this book to plant nerds, 20th century history buffs, and those looking for a good, factual mystery. It’s not terribly long and reasonably enjoyable despite some slow bits. But remember to read with a skeptical eye and judge the facts for yourself.

Give up? The grasshopper mouse! Onychomys is a genus of small mice native to western North America. The three species, O. leucogaster, O. torridus, and O. arenicola, have overlapping ranges with O. arenicola (Chihuahuan grasshopper mouse) stretching down into Mexico, while O. leucogaster‘s range reaches up to southewestern Canada. They are desert and arid adapted rodents, able to survive harsh conditions very well and are mostly found in desert, scrub, and dry plains in their ranges. Their characteristics and behavior are all very similar so I’m going to talk about the genus as a whole, although there are minor differences between species in terms of diet, habitat, etc.

Onychomys mice are very small, usually just a little over an ounce. They are actually quite adorable, with darkish brown to gray fur on their backs and light to white fur on their undersides, and a short, thick tail less than half the length of their bodies. They have relatively small ears and, although not bipedal, rise up on their hind legs and use their front limbs for various tasks rather regularly. If you were to see one in the wild, you would just think, “hey, a mouse with a short tail!”.

What makes Onychomys special – and fiercesome -among the hordes of North America rodents is its carnivory. Actually, carnivory itself is not that unusual among rodents, particularly desert ones. While many species are adapted to specialize in seeds or plant material, most are more omnivorous, incorporating small arthropods and sometimes even carrion into their diets. It’s the level of carnivory of these little guys that is impressive. They eat almost exclusively meat – mostly insects but also scorpions, small snakes and lizards, and even other rodents!

Now, these are not animals they have found dead and consumed. Onychomys are hunters. Quite aggressive ones. They will pretty much go after anything about their size or smaller that moves (with a very few exceptions in species which have toxins that make them inedible which the mice can smell from a distance), and will attack unrelentingly until it is dead. When they are near prey they sniff to identify it and then track its scent trail, silently stalking it until they are close. Then they attack, lunging at the prey with open mouths and front paws, trying to subdue it with a killing bite. In the case of vertebrates, they often go for the back of the neck, severing the spinal cord with their teeth. With arthropods they often first try to disable whatever defense the animal has, removing the stinging tails of scorpions, for instance.

From Langley, 1986

They almost never give up on prey once they’ve decided to attack, although sometimes after it is dead they may decide it’s not edible and leave it. Onychomys are of the “kill first, ask questions later” school of predation it would seem. Scientists who have studied them are often astounded at their level of aggression and their heedlessness of danger, as they attack everything from harmless crickets to other mice to the most poisonous species of scorpions in North American with the same vigor. They’ve even been known to kill kangaroo rats and cotton rats much, much larger than them in the lab (although it’s unlikely they hunt those species in the wild). In the eastern part of their range, they hunt small prairie birds.

It takes them a bit longer to subdue something heavily armed like a scorpion, but they usually manage it. Part of the reason they are able to do this is that Onychomys species seem to be at least partially immune to neurotoxins. The scorpions will sting them during an attack, and while they may retreat briefly and seem to experience pain from the wound, the normal effects of paralysis didn’t set in and the mice will return to their attacks. In the lab, trials have been done giving the mice various drugs, including sedatives and anti-psychotics, to see if that will decrease their aggression towards prey or each other.

They don’t. Drugs that would lay you or I out flat seem to roll off the backs of Onychomys and they just keep on going. They are born fighters – fairly young mice raised exclusively in a lab setting are still efficient killers when presented with prey for the first time, even when compared with wild-caught mice.

So why are these mice so aggressive and carnivorous? It seems to be a desert adaptation. Water is a problem for everyone in the desert, particularly mammals. Many rodents have developed similar adaptations to conserve/obtain water. These are often a combination of be behavioral (only coming out at night, eating only the moist parts of plants) and physiological (kidneys that concentrate urine to prevent water loss, the ability to extract metabolic water even from fairly dry food sources). While Onychomys can concentrate their urine somewhat, they are not as efficient at it as many other desert species and they can’t get metabolic water from seeds like kangaroo rats (many of which never need to drink or even eat particularly succulent foods).

It's like something from Dune: "His water is mine, now!"

They get their water from meat. Animals have a lot of water in them, more than many desert plants. Onychomys essentially usurp the water carefully hoarded by other species in their own bodies for their survival. Trials have been done feeding these rodents exclusively on meat (other mice, beef, and liver) and they were able to live quite happily without drinking water for months. If the meat was cooked, reducing the water content, they lost weight and their health immediately went downhill. It takes a lot meat to supply an active mouse with all the water and calories it need to survive in the desert, and it takes a lot of aggression to produce the high number of kills necessary to maintain that supply.

Although Onychomys are rodents, they eat like carnivores and thus sort of act like them too. They live alone or in pairs with young, not unusual for mice, but they maintain particularly huge home ranges, up to nearly 8 acres for some males. Which is simply gigantic if you’re talking about a mouse the size of a salt shaker! They are nocturnal and maintain extensive burrows in their territory which they use to live in, to escape from other predators, and to store food in the winter. They patrol and defend their territories viciously, eagerly fighting, killing, and eating intruders of the same species and other rodent species. Females have even been known to kill and eat their mates.

And they are vocal. They make various calls of alarm and identification, including the infamous howl. When patrolling their territory, they will often rise up on their hind limbs, throw back their heads, and make a loud piercing, cry. They do this, of course, particularly on spring spring and summer nights when the moon is full, although it is unknown if this behavior is a mating call or primarily a territorial display. This has led to another common name for Onychomys – wolf mouse.

References:

Rowe, A., & Rowe, M. (2006). Risk assessment by grasshopper mice (Onychomys spp.) feeding on neurotoxic prey (Centruroides spp.). Animal Behaviour, 71(3), 725-734. doi: 10.1016/j.anbehav.2005.08.003.

Ruffer, D. G. (1966). Observations on the calls of the grasshopper mouse (Onychomys leucogaster). The Ohio Journal of Science, 66(2), 219-220.

Timberlake, W., & Washburne, D. L. (1989). Feeding ecology and laboratory predatory behavior toward live and artificial moving prey in seven rodent species. Learning, 17(1), 2-11.

Langley, W. M. (1986). Development of predatory behavior in the southern grasshopper mouse (Onychomys torridus). Behaviour, 99(3/4).

McCarty, R. (1975). Onychomys torridus. Mammalian Species, 59, 1-5

McCarty, R. (1978). Onychomys leucogaster. Mammalian Species, 87, 1-6

Additional information from Animal Diversity Web and “A Desert Calling” by Michael Mares

I was pleasantly surprised to find that the book is instead part scientific memoir of 30+ years of field work on the small mammals of the world’s deserts, and part non-technical exploration of the greater principles of ecology and scientific study as they related to arid climates. The two components are woven together fairly skillfully to create a narrative that is both personal and overarching, and includes many fascinating case studies of individual species and associations that any nature geek will eat up with a spoon. From kangaroo rats that can go without free water their entire lives to pink fairy armadillos that swim through sand dunes, around every corner is another fascinating desert mammal (usually a rodent), that you probably have never heard of before.

On the personal front he talks unflinchingly about the challenges of field work in a wry, understated style. These adventures include a brush with death at the hands of a bat-borne virus, tents being shredded by the wind, getting nearly hopelessly lost in massive thorn forests, and the time their field site was declared an open shooting range during an Argentine war (“It made continuing to work there difficult,” he tells us). He also explains in detail the process and necessity of collecting rodent and mammal specimens for further study in museum collections.

Digression: Although I understand that we could not properly identify, describe, and study animals without comprehensive museum  collections, study skins, and the data gleaned from dissections, I have to admit that personally I am rather squeamish about that part of field biology. I fully admit that this bias extends mainly to vertebrates and I will happily collect a bug any day of the week, and that this is probably hypocritical. I just have a hard time reconciling the fact that the first thing ecologists usually do when we discover a new or rare animal is kill it with our overall conservatory efforts. Although the author is correct when he points that there’s never just one rodent, I also find the argument that it would have died anyway rather a flimsy one. Basically,  I know collections and type specimens are vital to science, but have personal misgivings which may or may not be valid. Although since many of the collected specimens the author mentions seem not to have just gone to a museum as skins but also into his stewpot as dinner when he had no money to buy food I can hardly begrudge him. Back to your regularly scheduled book review.

The author also talked about the less obvious problems with field work such as money, politics, and internal strife in the countries one wants to work in. He is equally candid about the scientific process and his personal experiences of bringing biases to his work and learning to overcome them. He is honest about being wrong, and what happens when scientists make assumptions about things that haven’t been properly studied. In the 70′s, when he was doing much of his field work, there was an overwhelming tendency in ecology to assume that similar habitats should contain nearly identical community structure and populations, and that these models could be applied around the world (models usually based only on North American ecology). He explains over the course of the book what parts of these ideas were correct and which were not – and how he discovered the difference. Along the way he includes narrow escapes from death, tales of how he and his crew discovered several new mammal genera, a hymn of praise to taxonomists, and a plea for desert conservation around the world.

In terms of science, his main focus is convergent evolution. He uses individual case studies to show how animals in different deserts solve the same problems in similar (or in some cases, radically different) ways despite being only distantly related. The takeaway lesson is that while you can’t expect similar habitats to always produce identical creatures, there are a limited number ways of solving the problems create by living in an area without much water, and we see these repeated again and again in nature – although sometimes with novel twists.

The explanations of the adaptations and broader ecological principles are easy to understand for a lay person, but not dumbed down at all to those who already have a basic foundation in ecology. He includes all scientific names but does not insist on referring to them only by their scientific nomenclature, and is diligent about going back and reminding the reader of pertinent facts instead of just assuming they completely absorbed a new concept from a brief mention earlier in the book. Overall, it was an easy and engaging book to read, and while long enough to provide an in-depth look at many topics, was not so long that it began to drag before the end. I highly recommend this to anyone even vaguely interested in deserts or small mammals – although be warned, if you want to learn about birds, lizards, or plants, look elsewhere. The man writes what he knows.

This gorgeous plant is Echinocereus triglochiatus Englemann, also known as claretcup cactus. No matter how many times I see it, I still find it startling to encounter a cactus in bloom. It seem so rare and magical, even though it’s actually not uncommon for many species. We encountered many blooming cacti on our Memorial Day trip to Arches National Park, mainly prickly pears (Opuntia spp.) in yellow or pink, but we only saw a few of these and they are hands down my favorite for their rich, blood red blooms.

Claretcup cactus is actually not terribly rare, although maybe not as common as prickly pears, which grow simply everywhere. There are a number of varieties which can range from having dense spines like this to no spines at all. The flower shade can differ as well, from wine-colored like these to more orange-y or pinkish. One variety, the Arizona hedgehog cactus is federally listed as endangered, due to it’s extremely limited range.

In general, the claret cup cactus can be found all over the southwestern U.S. and northern Mexico, in Ponderosa pine, Pinyon – Juniper, Sagebrush, Desert or Plains grassland, Desert shrubland, or Southwestern shrubsteppe habitats. It often grow in dense mounds of up to 500 stems (remember, in cacti the “barrel” is the stem and the spines are the leaves), although can also occur as just one or a few stems at a time. The dense mounds may offer some protection from fire or predation to those plants on the inside. They also conserve temperature, keeping the plants cooler throughout the day and then rising in temperature towards the end of the day and keeping them warmer on cold nights.

The beautiful flowers are pollinated mainly by hummingbirds, and the fruit when it ripens is bright red, juicy and sweet. It is edible by humans and most other animals, and is probably a minorly important source of food some desert creatures. Some rodents dig burrows underneath claretcup cactus colonies and nibble at the roots, which can eventually kill the plants.

If you want to see these pretty plants in bloom, head to southern Utah, Colorado, Nevada, Arizona, New Mexico, or California in April through June.

Ecology/Evolution Links:

1: Plant and animal discrimination, you say? A group of 18 ecologist have taken to the pages of Nature to get us to stop hating on invasives. Sorry, I’m just not buying it. Not everything new is bad, but mostly what we’re talking about are virulent life forms redistributed by humans in an untimely fashion – not gradual migrations (Wired).

2: A very cool and unique aquatic air-breathing spider solves its oxygen problem by taking the atmosphere with it. It can effectively use its home-made bubble as a gill to extract oxygen from the water. Post includes nifty video (Not Exactly Rocket Science).

3: Super-scary superbug with enzyme NDM-1, previously discovered in an Indian patient found, is found at a U.S. military hospital in Afghanistan for the first time. Maryn McKenna explains what the big deal is – and why it should probably be a bigger deal (Superbug).

4: More spiders? I just couldn’t help myself. The incredible Dr. Bondar shows us that handindicapped spiders can still weave a good web, even if it is a little different-y. Don’t judge them – they can do missing two legs what I can’t do with all my legs (Carin Bondar).

5: Chimps just want it more. An *ahem* novel way of solving a spacial problem involving a peanut and a…well, just read for yourself (BBC News).

General Science Links:

1: You think things like rain, snow, and hail just happen on their own? Nope. Bacteria control the weather. Okay, not just bacteria but since I’m not sure I had ever thought about atmospheric bacteria before, I’m gonna give them most of the credit (Highly Allonchthonous).

2: What is an ocean gyre? How do they work? And will they pull your ship down to the depths of Davy Jones’ locker? Yar! Ocean gyres explained, with oceanographer Emanuele Di Lorenzo (EarthSky).

3: A succinct and coherent response to incoherent reporting on the Higgs-Boson. This week Deborah Orr from the Guardian confused “physics” and “religion”. And also “journalism”. Here’s a summary with well-deserved smackdown (And Another Thing…).

4: Yes, the lights stayed on this week, but turns out we’ve just been lucky so far. Solar storms of the magnitude of ones that occurred in recorded history could easily knock out a chunk of the electrical grid for years. Yes, YEARS. Start saving your candles and bear fat, people! (Scientific American)

5: A new report sheds some light on the genetic causes of autism (hint: it’s not fromsomething you stick in your kids arm) and why girls have it so much less often than boys. Although this study reveals even more complexity to the condition than previously thought, it may provide hope for treatment using the female brain as a model (Nature News).

Because-I-Feel-Like It Links:

1: What to make for dinner this weekend (a personal favorite): Scallion pancake and cold sesame noodles. Although personally, I prefer my scallion pancake with Thai sweet chili sauce over the soy-based sauce in that recipe.

2: How to mind your own business. Will it make you happier? Probably. Will it make those around you happier? Most definitely (The Happiness Project).

3: Lessons from “127 Hours”:  how the movie should have ended. There’s more to be learned from Danny Boyle’s intense epic than how to cut your arm off with a dull knife or that a GPS with emergency beacon is a good investment (The Oatmeal).

4: We all have friends who are, well, kinda fake. But do you have actual fake friends on Facebook? Well, you and I probably don’t but if we were important, we might! (BlogAds).

5: Rachel Held Evans offers some in-depth advice on freelancing, writing, and making money. A very down-to-earth perspective from someone who is  fairly successful but still struggles with the day to day aspect of paying the bills (Rachel Held Evans).

In any case, I’ve been having a lot of fun learning more of the plants around here, so I thought I would share another batch. First up we have some real nasty pieces of work who don’t belong in Utah at all.

This alien-looking plant is myrtle spurge (Euphorbia myrsinites), also known as donkey-tail or creeping spurge. As you can see, the succulent leaves grow in a spiral around the stem. The flowers themselves aren’t much to look at but the bracts around them turn bright yellow (the same way the colored leaves of a poinsettia do). For reasons beyond my understanding it’s a popular ornamental in many places, including here (where people are obsessed with their front gardens). Probably because it’s highly tolerant of dry conditions and vaguely attractive all year round. The problem is, it doesn’t stay in the garden. The same things that make it valuable as a plant for xeriscaping also makes it an ideal weed in Utah. It has escaped into the foothills and quickly taken over large swaths of land. It is currently on the state list of noxious weeds and is probably the “most wanted” invasive offender we have at the moment. It should not be planted in gardens, as it will get out. If you see it anywhere, remove it. But be careful – not only is it destructive and poisonous to eat, but the sap can irritate eyes and cause chemical burns to the skin so wear gloves and goggles before you tangle with it!

Another foothill weed in danger of taking over around this joint is Melilotus officinalis, also known as yellow sweet clover. This one is actually kind of pretty, and doesn’t stick out like as much of a sore thumb as the spurge, given all the native pea family species we have around here. But it still doesn’t belong here and is edging out our lupines and vetches that do belong. It’s got bright yellow flowers in a raceme and typical clover-type leaves. This one is an agricultural stray – it’s grown for hay for cattle and as green manure but the seeds are easily scattered to the winds. It’s an interesting choice for cattle food, as if it’s not properly dried and gets mouldy in storage it produces a toxin which causes internal bleeding and death in those same cattle. In fact, that toxin is extracted commercially from the species for rat poison! Not really something I want growing in my nature preserve (even if plenty of our native plants are just as toxic – at least they evolved here!)

Lastly in the bad boy category we have Dalmation toadflax (Linaria dalmatica). What is it with yellow and invasive plants? I’m gonna start thinking every yellow flower I see is a weed – and that would just be sad! Anyway, this plant actually looks a little bit like spurge before they both flower – it has a very upright stem with sessile leaves in somewhat of a spiral arrangement grasping it. They had me confused for awhile But as it gets closer to flowering it starts to branch and form flowers at the leaf axils – clearly pea flowers. The flowers have a very long spur on the bottom which distinguishes them from other pea relatives around here and are, of course, bright lemon yellow. It too enjoys open, sunny areas like we find in our sagebrush foothills and montane habitats where we should be seeing lupine, sunflowers, and native vetches. This is another escaped ornamental, although it’s haphazard branching is a little scraggly and screams “weed” to me. It’s mildly toxic if you eat it, but mostly its crime is, like the clover above, crowding out the natives.

Okay, onto some lovelies! My new favorite genus is Penstemon. Now, this is a large genus with representatives in North America and Asia, but there are a fair number of native Utah Penstemon species, which are beautiful blooming perennials found in the deserts, foothills, and woodlands of the state. If you want to grow something as an ornamental, grow these! Here are three that I’ve learned to recognize so far (all three I saw in Arches National Park, but they have been known to grow up here as well).

From left to right we have P. eatonii, P. palmeri, and P. utahensis, known commonly as firecracker penstemon, pink wild snapdragon or scented penstemon, and Utah penstemon, respectively. All Penstemons share some traits – they are generally upright, with opposite leaves that usually clasp the stem (sometimes to the point of surrounding the stem, as in P. palmeri). The have tubular, two lipped flowers and although the dimensions may vary, they nearly always have three lobes on the bottom lip and a haiyr, curling, infertile staminode in the mouth of the corolla which gives them the common name “beard tongue”. P. eatonii has one of the longest, narrowest tubes with the least flare at the end, and is usually bright orange-red. P. utahensis is similiar but with a bit more flare of the tube lips and tends to be a more purply red with slightly larger flowers. P. palmeri can be recognized by it’s large size, sweet smell, distinctive flower shape, and the leaves that completely surround the lower stem.

Finally, a yellow native flower! Last time I brought you Balsamorhiza sagittata, our early spring blooming “sunflower” with the fuzzy arrow-shaped leaves. Well, that is done blooming now, and we’re starting to see another sunflower that at first glance looks just like it. Wyethia amplexicaulis, northern mule’s ears. Closely related it begins blooming just as arrow-leaved balsam root finishes it’s show. It is a bit taller than it’s cousin, and the flowers have smaller centers, and longer and more slender ray flowers – and fewer of them. But the most obvious difference to the naked eye is the leaves. Instead of soft and fuzzy arrow-shaped leaves, northern mule’s ears have dark green, glossy, elliptic leaves tapering to a point. They tend to grow rhizomatously in small stands and they help keep the sunflower show going on through the summer here!

Last but not least is a dainty little flower I spotted on a hike up Bell’s Canyon this weekend. Small-flowered woodlandstar (Lithophragma parviflorum) is aptly named. These little, delicate blooms with feathered petals grow straight up on slender stalks, one to three each (although they can have as many as 14 flowers per stalk), and dotted the mid-elevation moist meadows just like stars. I find them completely enchanting. The basal leaves are small, a little scraggly, and deeply, unevenly, palmately lobed, bearing a little resemblance to some carrot family relative (which it’s not – it’s in the saxifrage family). They can be found in any number of open habitats, from montane to sagebrush desert to prairie, but they do seem most at home in woodland clearings. They don’t tend to form stands but rather dot a large area with a couple plants here and a couple there, so they are a constant, understated presence.

Simple illustration of genetic distribution and the founder effect. The original population is on the left with three possible founder populations on the right.

So what happens then? Well, normally in a large population you have a pretty even distribution of genes that cause certain traits (eye color, tail length, you name it). As long as there is no major selective pressure being exerted for or against that trait (ie, as long as blue eyes don’t lower your chances of survival and reproduction), the distribution of those genes within the population is going to stay roughly the same. Now, if you take a small sample of individuals out of that group, the distribution of genes that cause different traits might be the same as in the large population, but there is a much greater chance of gene distribution being skewed one way or the other.

It’s like how when you flip a coin 1,000 time it will almost certainly be heads about 500 times and tails about 500 times, but out of those flips it’s possible and even likely to get a run of, say, ten heads in a row. So out of a population of individuals where maybe half are spotted and half are striped, you could end up with a subpopulation of all striped individuals. In fact, in a population where most are spotted and only a few are striped (maybe striping is a recessive trait in this species) you could still end up with a subpopulation of all striped individuals.

It’s when they start to breed that things get interesting. These individuals suddenly have a much smaller genetic pool to paddle around in, and that can cause change to happen very quickly. As we know, a small population can be trouble because genetic diseases thrive on homozygosity. So one of the first things that is likely to happen is that genetic problems that were relatively rare in the large population (because if you carried the gene for it you were not very likely to mate with someone else who also had it) become more commonplace. Sometimes this may actually end up eliminating the trait from the gene pool entirely because all the individuals with the genes for it produce only offspring that die and it doesn’t get passed on, so you’re left with an even smaller pool containing less muck. But sometimes it sticks around and becomes more common than ever – like the sad case of Tay-Sach’s disease in the Ashkenazi Jewish population.

Other traits may be more common throughout the population that never would have been in a larger population, because they were not particular advantageous (or disadventageous either). And since events that cause founder effects are often associated with a change in conditions or location for the smaller group, a change in selective pressure can mean that a trait that used to be rare and evolutionarily neutral can quite suddenly become common and desirable. Natural selection takes over and speciation from the parent group can happen much more quickly than under other conditions. We see this on islands especially, when a small group has emigrated there – new genetic distribution + new environmental conditions = evolution has a party.

The founder effect is especially strong in species that have slow reproduction rates, particularly large mammals, because the population stays small for a long time after the event that separated them. Species that reproduce copiously are less effected. If you have a million beetles, and you separate 100 of them… it won’t be that long before you have another million beetles. Of course there will still be a change in genetic distribution from the separating event, there’s no getting around that, but it won’t continue to compound for as many generations because they’ll be back up to a large breeding population that much quicker.

One of the most commonly cited examples of the founder effect is cheetahs (Acinonyx venator), particularly the cheetahs in southern and eastern Africa, which are distinct populations. And frankly, neither of them is doing that well. You see, cheetahs are so genetically close to each other that they can actually accept skin grafts from one another. Scientists think that there was a catastrophic event around the end of the last Ice Age that killed most of the existing cheetah population and caused a genetic bottleneck with the existing cheetah population. The few that were left could only breed with each other and the founder effect has a created an extremely homozygous population even thousands of years later. Another event maybe a hundred years ago, most likely hunting and human settling, caused them to split into two geographically distinct populations and decreasing the breeding pool of each even further.

"Electro-what? On my WHATS?"

The south African population is the worse off, having undergone more inbreeding resulting in such genetic problems that it can barely reproduce any longer, but both populations suffer from a low sperm count, low sperm motility, and deformed flagella, making it highly vulnerable to extinction and not all robust. (How do scientist know about the sperm? Capture and electro-ejaculation sampling. It is exactly what is sounds like.) Cheetahs also often throw up unusual or strange color morphs more often than other felids due to increased likelihood of individuals with the same recessive trait mating with each other. The only reason cheetahs may have survived as species this long is that most of the fatal genetic illnesses were probably rapidly bred out after the event that reduced the population, so although they have trouble reproducing, when they do the offspring are generally healthy (or at least not unusually likely to be unhealthy). Putting the two populations back together may be a start towards reclaiming a little diversity and giving them better odds on species survival.

Humans have been uniquely shaped by the founder effect, in a case of what is called a serial founder effect. Basically, we evolved in Africa and migrated to the rest of the world. But it didn’t happen all at once. A small group left the larger group and went north and settled down in a likely spot. They were subject to the founder effect, the population changed in response to the new conditions and the new genetic distribution, and grew larger. Then a subset of that population got tired of the crowds and set out for a new spot to settle in, where they didn’t have to share resources, and they too were subject to the founder effect, and so on. This can actually be traced by genetic studies done today. In general, the people in Africa today, descendants of the original large gene pool have the highest genetic diversity in their population, followed by people on the Indian subcontinent (one of the first places humans settled when they left Africa) and so on. Places like Iceland, which was settled late and is also an isolated area, have some of the least genetic diversity on the planet and a high incident of recessive traits like blonde hair and blue eyes.

Royal spoonbill says, "We didn't need those guys anyway!"

So as you can see, the founder effect can have a pretty strong effect, good, bad, or just different, on populations. And it has probably been the initial starting push for the speciation of many species we know today. But it is important not to assume that all speciation events are the result of a founder effect – natural selection doesn’t necessarily need any help to develop new species. For instance for a long time it was thought that the royal spoonbill (Platalea regia) in Australasia and the black-faced spoonbill (Platalea minor) in eastern Asia had speciated as a result of the ancestors of the black-faced spoonbill being separated physically from the parent population and undergoing a founder effect combined with new selective pressure in their new home. But recent studies have shown that there was almost certainly genetic mixing between the two populations long after the black-faced spoonbill ancestors had taken up residence in their new digs. It’s more likely speciation occurred slowly as one part of the group began to take advantage of new resources in a new area while others did not, and they slowly began to preferentially mate with others who did the same.

Founder effect is a vital concept in the study of populations and of evolution, but it should not be given credit for all genetic change. There are other mechanism that can effect selection and evolution, and we will look at this in future eco-vocab posts.

Yeung, C. K. L., Tsai, P.-W., Chesser, R. T., Lin, R.-C., Yao, C.-T., Tian, X.-H., et al. (2011). Testing founder effect speciation: divergence population genetics of the spoonbills Platalea regia and Pl. minor (Threskiornithidae, Aves). Molecular biology and evolution, 28(1), 473-82. doi: 10.1093/molbev/msq210.

Deshpande, O., Batzoglou, S., Feldman, M. W., & Cavalli-Sforza, L. L. (2009). A serial founder effect model for human settlement out of Africa. Proceedings. Biological sciences / The Royal Society, 276(1655), 291-300. doi: 10.1098/rspb.2008.0750.

Ramachandran, S., Deshpande, O., Roseman, C. C., Rosenberg, N. a, Feldman, M. W., & Cavalli-Sforza, L. L. (2005). Support from the relationship of genetic and geographic distance in human populations for a serial founder effect originating in Africa. Proceedings of the National Academy of Sciences of the United States of America, 102(44), 15942-7. doi: 10.1073/pnas.0507611102.

OʼBrien, S. J., Wildt, D. E., Bush, M., Caro, T. M., FitzGibbon, C., Aggundey, I., et al. (1987). East African cheetahs: evidence for two population bottlenecks? Proceedings of the National Academy of Sciences of the United States of America, 84(2), 508-11. Retrieved from http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=304238&tool=pmcentrez&rendertype=abstract.