Tar Pits, Dung Beetles, and Megafauna

Today Los Angeles is a city with a reputation for excess, dominated by cars and actors, and there is a reason for this.  Money.  Money in the form of oil.  The combination of oil and money led to the nascent fossil fuel industry teaming up with the budding car industry in the early 20th century to sabotage the successful street and rail car industry in the Los Angeles basin.  Money led to loose laws which led to crime, gambling, and guerrilla movie studios moving into the LA area, searching for places that were outside the influence of the film establishment of the times.  All of these things are interesting, but without the oil it is unlikely Los Angeles would have taken the trajectory it did.

Oil Fields, Signal Hill, Los Angeles 1914

Oil Fields, Signal Hill, Los Angeles 1914 – source: National Geographic archives

Oil is usually found deep under ground, but the greater Los Angeles area up through the Santa Barbara area is one of a few places in the world where oil is not just close to the surface, it is on the surface, bubbling in cold pits of bitumen, also known as asphalt and tar.  This asphaltum has been important to humans for as long as they have lived in the region.  In the past it was primarily used to waterproof boats, water carriers, and cooking vessels or as an adhesive.  Now, of course we use it to make a whole range of products from gasoline to Vaseline, rubber, plastics, pantyhose, parachutes, paint, detergents, antifreeze, golf balls, and more.

Bitumen occurs where vast amounts of living material (plankton, diatoms, or plant material usually) were deposited in a quiet anaerobic environment, such as a lake or sea floor, and left alone for a long, long time.  In essence, it is liquid coal.  Coal beds are sometimes repositories for incredible collections of fossils.  These ancient remains and offer a window into the deep past, but for a window into the more recent past we need something a little different from coal.  Bitumen provides one of the best preserving agents for more recent remains.

Near Hollywood there is a famous bitumen pit redundantly named the La Brea Tar Pits (literally “The Tar Tar Pits”).  Between approximately 38,000 years ago and 11,000 years ago the La Brea Tar Pits were very active.  An enormous variety of animals and insects were lured to the waters of what appeared to be a rich wetland and were trapped by the sticky tar that lay beneath the shallow layer of water.  A few posts back I brought up the fact that condors are representatives of an extinct assemblage of fauna.  The La Brea tar Pits provide a window into that now extinct assemblage.  Los Angeles was a land of giant bears and jaguars, pygmy pronghorn antelope, camels, mammoths, dire-wolves, great birds of prey, giant ground sloths, and numerous other animals.  

Mural of the La Brea Tar Pits during the Quaternary

Mural of the La Brea Tar Pits during the Quaternary

Animals trapped by the sticky tar aroused the interest of predators and scavengers which were themselves trapped by the tar.  Herbivores, carnivores, mammals, birds, and insects all fell prey to the tar pits and many of them have been preserved in astoundingly good condition.

Pygmy Pronghorn (Capromeryx minor)

Pygmy Pronghorn (Capromeryx minor)

Along with the large animals is one of the best collections of preserved insects in the world.  Most people know that insects are important in a sort of general way.  In recent years honeybees have been in the news quite a bit and their importance in maintaining our food supply has reached the mainstream audience.  I’ve mentioned the importance of both ladybugs and dragonflies, but these are iconic and popular insects, very much in the public eye.  There are many other insects that have an importance far beyond what their diminutive size would indicate.  One of these is the dung beetle (Scarabaeinae).

Until recently much of the planet was home to a wide range of large animals, grouped into the catch-all term “megafauna”.  This is a generic term for any animal massing more than 45-100 kg (100-220lbs).  Most of the recent megafauna of each continent (with the exception of Africa) went extinct shortly after humans reached the respective region.  Here in North America we had great mammoths, elephant relatives, standing 4 meters (13 feet) tall at the shoulder and weighing 9 metric tons (10 short tons).  You can walk under the tusks of the mammoth skeleton in the La Brea Tar Pits, reach your hand up as high as you can, and the tusks are still out of reach.

Colombian Mammoth (Mammuthus columbi)

Colombian Mammoth (Mammuthus columbi)

Numerous types of ground sloth roamed the area, including both the Shasta and Harlan’s Sloths.  Harlan’s Ground Sloth was not the largest and even it stood 3 meters (10 feet) tall and weighed more than a ton.

Harlan's Ground Sloth (Paramylodon)

Harlan’s Ground Sloth (Paramylodon)

The Antique Bison, some 15-25% larger than modern bison roamed the region,

Antique Bison (Bison antiquus)

Antique Bison (Bison antiquus)

And there were, or course predators of all sorts.  Dire Wolves are particularly well represented in the La Brea Tar Pit fossils.

Dire Wolf (Canis dirus) skulls.  One panel of a 3-panel display.

Dire Wolf (Canis dirus) skulls. One panel of a 3-panel display.

There were large numbers of these animals and, like all animals, they had to eat.  The larger the animal, the more it eats.  Modern African elephants eat 100-300kg (220-660lbs) of food per day, so it is reasonable to expect that the Colombian mammoth would eat at least that much per day, if not more.  Then, just on the herbivore side of things, there were the giant ground sloths, horses, camelids, bison, elk, antelope, peccaries, deer, and numerous other species.  Additionally there all the predators; giant jaguars, sabre-toothed cats, dire wolves, American cheetahs, bears of all sorts, including the giant short-faced bear, and more besides them.

All animals must eat, and everything they eat must come out eventually.  This is something we don’t really think much about: what happens to all the animal dung?  How much of it was there?

We don’t really have any good idea just what the animal numbers were like in the past, but we do have a very good idea of the numbers of another kind of modern megafauna.  Cows.  The numbers of cows in the US probably only represent a middling-small portion of the total amount of large megafauna in the US portion of North America, but they give some insight into the kinds of numbers we are talking about when it comes to dung quantities.

The 2006 article by Losey and Vaughan provides some insight to those numbers.  Each cow can produce approximately 21 cubic meters of waste per year, that’s a volume roughly equivalent to 1.3 VW buses worth of dung per year per cow.  In 2004 there were nearly 100 million head of cattle in the US, that means more than 2 billion cubic meters of poop per year, just from cows… I’ll let that image settle in.  For comparison that’s enough to cover  Manhattan to a depth of about 70 feet (21 meters) or Disney World to about 60 feet (18 meters) in cow manure every year (in other news: Disney World is larger than Manhattan).  That’s just from the cows and just the ones in the US.

What happens to all that crap?  Enter the humble dung beetle.  For the portion of cattle that are fortunate enough to be in fields, dung beetles take care of the waste.  According to Losey and Vaughan each year dung beetles save ranchers $380 million dollars in clean-up costs.  A 2001 article by Michelle Thomas indicates that without dung beetles each year we would find 5-10% of each cattle acre unusable due to dung pile-up.  Dung beetles are so important that foreign species of dung beetles have been imported to the US and elsewhere for use in areas that experience heavy livestock use.

Dung beetles range in size from just a few millimeters to several inches in length.  Their size is dependent on the size of the dung they have to deal with.  Currently Africa has the largest land animals and the largest dung beetles.  North America used to have an enormous range of very large animals with correspondingly large droppings.  As you might expect there were some very large dung beetles living here to take care of those droppings.  The large beetle on the left is an extinct giant water beetle similar in size the the large, extinct dung beetles.   This beetle is about 2 inches (5 cm) long.

Different species of dung beetles found in the tar pits.  The large one is extinct.

Different species of small dung beetles found in the tar pits and an extinct giant water beetle that is about the size of the large extinct dung beetles.

Ecosystems are delicate things, subject to trophic cascades, as I have previously mentioned, full of unexpected consequences and side effects.  Most of the great predators in North America died out when the large herbivorous megafauna became extinct.  Scavengers also suffered, amongst them the dung beetles.  All the large dung beetles in North America swiftly followed the rest of the megafauna into extinction.  Currently in North America the dung beetles are small, more like the insects to the right in the image above than the large tan one (you can check out photos of them here).

For many people the response to this is a shrug of the shoulders, but the effects of these beetles going missing had a tremendous effect on the ecosystem, in particular on plant growth and distribution.  We don’t know, and probably will never know how great an effect their absence had.  Dung beetles, the Scarabaeinae, are extremely important ecosystem engineers, gathering fresh dung and burying it as a food source for their developing young.  By doing so they fertilize and aerate the soil, speeding up the cycle of nutrient return by putting the nutrients in a safe place where the plant roots can get to them and where they are less likely to be washed away by rain or desiccated by the sun and blown away.  In addition, dung beetles are important in limiting the spread of diseases and parasites by removing fly and pest breeding sites.

Understanding the details of the world, the interactions, the interconnectedness, the causality of it is difficult.  When we look at the present we have the fine resolution, but lack a context.  When we look at the past we establish a context, but lack the fine scale resolution.  When we look to the future, as we must, we need to be able to combine the insights of the past and the present to predict the consequences of our actions.

Hopefully we are getting better at this, but I cannot help but look at connections like that between the mammoth, dung beetle, the dire wolf, the distribution of plants, and the radiating effects of that interleaving and wonder what vital link, or set of links, we are failing to see right now and what what will mean for our future.

The Archives at the La Brea Tar Pits

Archives at the La Brea Tar Pits

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Apologies for the multiple posting.  I made an edit using the WordPress App on my iPad and it deleted the original post.  I had to restore it and repost.

The Beneficial Lady Beetles: Good Luck Bugs or God’s Little Cows

J.B.S. Haldane, one of the founders of population genetics, is credited with saying, “If one could conclude as to the nature of the Creator from a study of creation it would appear that God has an inordinate fondness for stars and beetles.”  Like most quotes attributed to famous people, it is probably apocryphal, but the point is valid.  There are a lot of Coleoptera species in the world, not as many as there are stars in the sky, but 1 out of 4 animal species in the world is a beetle of some sort. Many people experience an inordinate queasiness around insects and other arthropods.  There are a few species, however, that rarely elicit distaste.  Of these the Coccinellidae or  Ladybugs (also called Lady Birds and Lady Bird Beetles) are particularly adored.  The most iconic of these are the jewel-like red and black spotted types, of which there are many.  All told there are some 5,000 species of ladybugs around the world, not all of which are red, around 450 in North America, and approximately 175 species in California alone.  All ladybugs share the endearing, rounded shape that their name, Coccinellidae (meaning “little sphere” – Note: some sources suggest that this name means “scarlet”), derives from.  These are primarily solitary little beetles that are found nearly everywhere there are a lot of plants, especially in gardens, fields, grasslands, and shrublands.

Convergent Ladybug (Hippodamia convergens) on manzanita leaf

Convergent Lady Beetle (Hippodamia convergens) on manzanita leaf

The rounded shape that gives ladybugs somewhat of a bumbling appearance is actually highly effective armor to protect them from ants.  “Why do they need protection from ants?” one might ask.  Well, contrary to their appearance, they are fierce and merciless predators, specializing in aphids.  Hungry ladybugs will eat a wide variety of insects, but to reproduce they must eat aphids and eat large quantities of them.  An adult Convergent Lady Beetle (Hippodamia convergens), a common and easily identifiable ladybug found in the Americas from Canada to northern Bolivia, eats 40-75 aphids a day with the larvae eating only slightly fewer.  Aphids have a special relationship with ants. Aphids by themselves are small, defenseless, and relatively harmless, but, as any gardener or farmer knows and fears, they can very quickly reach immense numbers.  Aphids live off of plant sap, sinking their mouthparts into soft plant tissue like miniature vampires.  Plant sap is high in sugars that the aphids excrete in the form of honeydew.  Ants, like many animals, have an affinity for sugar and collect the sweet honeydew from aphids, in some cases treating them not so differently from the way we treat free range cows.  In exchange for honeydew the ants protect the diminutive aphid herds from predators.  Predators such as the voracious and heavily armored ladybug. Farmers and gardeners have a particular fondness for ladybugs as they can potentially save a whole crop from devastation.  The name “Ladybug” or “Lady Beetle” supposedly derives from vast numbers of ladybugs descending on pest infested fields after villagers prayed to the Virgin Mary to protect their crops.  In Germany one of the names was Mary’s Chicken, in Sweden The Virgin Mary’s Golden Hen, in Spain Gods Little Cow, in Turkey they have the name Good Luck Bug, and in Yiddish they are called Moses’s Little Cow.  In Russia seeing a ladybug indicates that a wish will soon be granted or is an indication to make a wish.  Before Christianity took over northern Europe their name was tied with the Norse goddess Frejya rather than with Mary.  Nearly all the names for ladybugs indicate how well respected and loved they are, though there are a few names reflect the burning aspect of the chemical defense they use to deter larger predators. The Convergent Lady Beetle is particularly favored by farmers in the US as a natural pest control method.  Despite their solitary nature one acre of alfalfa suffering from an aphid infestation can support up to 50,000 ladybugs by Dr. Kenneth Hagen’s estimate.  Many farmers take preemptive steps to control aphid infestations by releasing ladybugs in bulk, purchasing buckets containing between 70,000 and 80,000 individuals per gallon.

Convergent Ladybug (Hippodamia convergens) in a hibernation swarm.

Convergent Lady Beetle (Hippodamia convergens) in a hibernation swarm.

If ladybugs are solitary, how does one collect 70,000 of them?  They migrate; I’ve mentioned insect migration before, but this is not the extraordinary long distance flight of dragon flies or monarch butterflies.  This is a short migration up into the hills and mountains where the ladybugs cluster in protected areas and wait for the weather to warm up. Ladybugs do not fly if the temperature drops below 55ºF (13ºC) and the Convergent Lady Beetle spends the cooler months in diapause, an insect analogue to hibernation.  In California, Convergent Lady Beetles living in the Central Valley head up into the Sierras while those closer to the coast find local hollows and protected areas to gather in.  They often show fidelity to specific sites and, in the Sierras, can gather in vast numbers.  Individual sites can have as much as 500 gallons of ladybugs, or more than 37 million individuals.  Collectors scoop these ladybugs up and sell them to agriculturalists around the country. In the coastal portions of California the distances the ladybugs travel to wintering sites is not as great and they do not gather in the same density.

Hippodamia convergens in Redwood Regional Park

Hippodamia convergens in Redwood Regional Park

One place to see Hippodamia convergens gathering is in Redwood Regional Park in Oakland.  There is one spot that they return to, a glade near one of the streams.  They coat the low growing and dead vegetation, branches, and logs in an intermittent film of slowly moving red gems.

Hippodamia convergens on dead vegetation

Hippodamia convergens on dead vegetation

In some spots they clump like globs of foam stuck to old hemlock stalks, in other areas they gather on lichen covered logs.

Hippodamia convergens on log

Hippodamia convergens on log

They are not completely dormant.  If you sit and watch them for a few minutes you will see them slowly mill about.

Hippodamia convergens on twig

Hippodamia convergens on twig

In a few places they form a nearly even coat over branches.

Hippodamia convergens covering a branch

Hippodamia convergens covering a branch

In other spots they cluster between the stalks of old flower-heads.

Hippodamia convergens on flower head

Hippodamia convergens on flower head

Finding these conglomerations of ladybugs is particularly exciting, in part as it is so shocking even when you are expecting it.  We have so few opportunities to see large numbers of wild animals in their natural environment any more that when we do it is particularly impacting, especially if it is of a type of animal we usually see as solitary individuals.  The ladybugs are also very pretty, which is always a bonus. *** Macro photos taken with a 70-300mm lens and kenko macro-tubes at a high ISO due to the late time of day and shade.

Plant Defenses – myriad strategies

Plants, as you might imagine, devote a great deal of energy to defending themselves from predators.  We humans have a natural bias towards animals, creatures that are like us in that they are mobile and respond to stimulus on a timescale similar to ours.  Plants operate, with a few notable exceptions, on a slower timescale, but this in no way should be taken to imply that they are any less interactive vis-a-vis their surroundings.

Plants react to light and dark, sense gravity, moisture, nutrients, and toxins; some can “feel” other organisms (Venus fly traps for example) or “hear” sounds (sensitive plants).  One thing all organisms must cope with is predators and competitors, and all organisms need defenses against these threats.  Plants are no different in their needs, but they are largely immobile, so some of their defenses tend to take a different form than they do in animals.  Surprisingly, their defenses are not as different from animal defenses as one might expect.  I would break plant defenses into three broad categories: chemical, physical, and co-optive.

Chemical defenses often involve toxins of one sort or another or pungent aromas.  Some of these we assiduously avoid, such as certain members of the Sumac (Anacardiaceae) family like poison oak (Toxicodendron diversilobum) and poison ivy (Toxicodendron radicans) due to the allergen urushiol found in the sap.  Other plants using chemical defenses we consume with great relish, many of our foods and spices, for example, derive their strong flavors from the defenses the plant manufactures to deter herbivorous predators.  Mints (Lamiaceae), rosemary, cinnamon, peppers, and onions are good example of common foods we consume that utilize strong chemical defenses.  Other chemical defenses we find recreational and/or medical uses for; ephedrine from plants in the Ephedra family, THC from Cannibus, and cocaine refined from alkaloids found in the coca family (Erythroxylaceae) all have enormous economies reliant on them.

Coca cultivation in Bolivia near Coroico

Coca cultivation in Bolivia near Coroico

Chemical defenses are enormously interesting and extremely sophisticated, but they are largely hidden from us until we are affected by them.  This is part of the reason why eating unfamiliar plants is so dangerous, there are few good ways to determine if a plant is edible upon first encounter.

Physical defenses are the most obvious to us, especially when they come in the form of thorns and barbs, but those defenses barely scratch the surface of the types of physical defenses plants can employ.

An impressive but unsubtle defense - Ceiba speciosa in the Bolivian Amazon

An impressive but unsubtle defense – Ceiba speciosa in the Bolivian Amazon

Sharp pokey bits may defend plants against larger herbivores and chemicals help to protect them from insects or pathogens, but other plants themselves can be, if not predatory, at least detrimental to large trees.  Lianas and other climbing plants, epiphytes, parasitic plants, and even other large trees may need to be defended against.

Strangler fig (Ficus spp.) overwhelming a palm tree's defenses - Bolivia

Strangler fig (Ficus spp.) overwhelming a palm tree’s defenses – Bolivia

The photo above I find particular interesting as the palm tree being overwhelmed by the strangler fig usually has an effective counter to this sort of attack.  Palm trees and tree ferns both allow their old fronds to droop as they age, sheathing the trunk and providing a structure for climbing plants to adhere to.  Eventually these canny plants shed their dead fronds, and with them the uninvited plant guests that have taken up residence.  Many trees employ a similar strategy, eucalyptus and madrone have smooth bark that regularly sloughs off in strips.  The combination of smoothness and shedding makes it difficult for other plants to gain purchase.

Strangler fig is a generic term for a wide variety of tropical fig trees sharing a similar life strategy.  These are the “matapalo” or killer trees.  Rather than growing from the ground and climbing up these trees co-opt animals to carry their tiny seeds through the canopy.  A small portion of these seeds wind up in a place like the crotch of a branch or a broken limb where organic material has built up.  The young fig sends dangling roots down from the canopy in search of nutrients, eventually reaching the ground and transitioning from a vine-like life style to a more tree-like life style.  More and more ground-seeking tendrils make their way downwards, eventually ringing the host tree and strangling it.  As this happens the strangler fig uses the original host as a scaffold and sends its own canopy high enough to overshadow the unfortunate host.  The palm tree in the photo above was underneath a tree the strangler fig took root in and had the misfortune to be attacked from above rather than from below.

Color is an oft overlooked plant defense, the role of which is still being debated.  I don’t mean fruit color, that is blatant advertising and animal bribery.  The color and pattern of the leaves and trunk of plants may serve as defense against predators.

The most familiar example of this is variegation in leaves, that is the white or colored mottling seen most often in ornamental plants, but also occasionally found in the wild.

Variegated hibiscus leaf. Source

Color mottling in leaves is often a symptom of nutrient deficiency, insect predation, viral infection, or genetic chimerism (expression of more than one genetic sequence in a single organism).  In most of the above cases this indicates poor health in the plant, and a plant in poor health makes for an unappetizing meal.  Some plants seem to capitalize on this and mimic the effects of various types of poor health (eg. false leaf damage and variegation) to trick predators into avoiding what appears to a be an un-nutritious meal(1)(2).  Bark color, whether natural or as a result of mutualistic lichen growth may be a predator deterrent as well, as lighter colors may make predators more visible to other predators higher up on the food chain.

Before moving on to animal co-option I should mention one other strategy employed by some plants.  Outgrow your predators.  In this case a plant allocates few resources to defense and focuses on growth and/or reproduction.  Balsa trees follow this strategy, they grow astoundingly rapidly and produce copious numbers of seeds.  They are not long lived and have few toxins, as a result they are subject to immense amounts of predation from a wide range of species.  Some of these, such as tapirs, they avoid by growing out of their reach.  Others are more problematic.  I saw a 30 foot tall young balsa tree completely stripped of leaves by leaf cutter ants in less than two days.

Basla saplings - Bolivia

Basla saplings – Bolivia

The most interesting of the plant defenses, to my mind, is animal co-option for defense.  Ants are probably the animal most often co-opted by plants.  We don’t often think of plants as being the ones to manipulate animals, but that is more a reflection of our animal bias than of the true nature of things.  Plants are highly manipulative, in their slow manner.  Like many effective manipulators, they accomplish their ends via bribes (and in a few cases by outright lies – orchids tricking bees into trying to mate with the flowers is a classic example of vegetative duplicity).  Ants are employed as guards by a great number of plant species.

When I first arrived in the Amazon I recall thinking to myself, “Cool, I hope I get to see some of the ant/plant mutualism.”  The first plant I looked at closely was a common understory shrub in the widespread and diverse Melastomataceae family.

Melastomataceae with ant sheltering nodes at the base of the leaves - Peru

Melastomataceae with ant sheltering nodes at the base of the leaves – Peru

At the base of each leaf there was a hollow, swollen node with two small openings on the underside.  Tiny ants occupied these nodes and would rush out to defend the plant when it was bumped.  This is a surprisingly effective defense against herbivores of all sorts, insect and mammalian.  All through the Amazon (and elsewhere in the world) ants and plants have banded together.  I found arboreal ferns with hollow rootballs harboring and colonies, tall cecropia and smoke trees (“palo diablo” – devil trees) with hollow trunks harboring vast numbers of fierce and painful fire ants, and evocative single species plant stands called Chullachaqui gardens.

According to legend the Chullachaqui is a forest guardian spirit that keeps small monoculture garden plots scattered here and there in the forest.  One should be wary entering these areas, ask permission first, and be careful not to damage any of the plants the Chullachaqui grows.  This is good advice as the Chullachaqui gardens are home to a species of ant that lives underground and kills all the plants growing on the surface except for one species.  Animals that interlope are attacked also attacked and the bite and sting of the ant is painful as it contains formic acid.

One of the neatest ant-plant interactions comes in the form of hanging “ant gardens”.

Ant garden in Peru with Monstera spp.

Ant garden in Peru with Monstera spp.

The dense cluster of plants in the above photo is growing from an arboreal ant hive.  Certain plants produce seeds with fatty nodules on them that ants eat.  Ants collect the seeds and store them in their hives, clipping the edible portions off as needed.  Some of the sees sprout and send their roots into the rich material of the ant hive, reinforcing it and protecting it from rain and predators as they grow.  These hanging ant gardens are found throughout the tropics.

Ant-plant interactions are not limited to the tropics.  Some trillium species bribe ants with food to carry their seeds to good growing locations and elderberries in certain portions of North America keep a protective coterie of ants nearby by bribing them with sugar produces from nectaries grown specifically for the ants.

Co-opting an animal may well be the most sophisticated of plant strategies for its subtly, specificity, and efficiency.  Energy cost is at the root of all these strategies.  A plant only has as much energy as it can collect from the sun and soil nutrients.  It must balance its energy use amongst growth, reproduction, and defense.  Every defense a plant employs lessens the amount of energy it can devote to growth and reproduction.  Combining forces with other species can provide a relatively low-cost way for a plant to gain an aggressive, mobile, multi-pronged defense force.  Ants, for example defend their plant hosts with both physically damaging attacks and with chemicals.  That’s a two-for-one defense with an added bonus of rapid deployment for the relatively minimal investment of a home or some food.

Humans may well be mammal plants have trained best.

***

A note about the images and film vs digital in the field:

These photos (with the exception of the hibiscus leaf which is not mine) were taken in 2005 with a well used and abused Canon AE1 with a 50mm 1.4 lens and scanned from the negatives by the developing kiosks in Peru and Bolivia.  The quality of images reflects both the environmental stresses put on the camera and film and the irregular scanning quality.

For long periods of time in the field I still think that film is the better option.  I was in the jungle for months at a time, sometimes in places with no power (20+ days hiking and on a raft in Bolivia for example) and in hot, humid conditions with frequent thundering downpours and rampant mildew growth.  I love the digital camera I use now, but it would have been completely unusable for the majority of the time I spent in South America.

Film cameras do still have their place.

Chaparral Yucca, Spanish Bayonet – the many named Hesperoyucca whipplei

Despite the cool breeze blowing off the Pacific visible 1300 feet below (400 meters) and four and a half miles away (7 kilometers), it is hot.  Blisteringly so.  The sun beats down on me heating my skin like the bank of coals left over from a bonfire.  Across the valleys the slopes of the Santa Monica mountains waver in my vision as the rising heat warps the air, changing its density and bending the light.  At my feet what looks like heat shadows dance, but upon closer investigation I realize that it is a 6 inch (15cm) layer of extremely fine alkaline dust blowing over the trail like a Martian sandstorm seen from orbit.

This is one of the most diverse areas of California for birds, but all I hear is a single crow cawing as it glides over the ridge and falls into the canyon to the west of me.  Dressed all in black, even the crows must be broiling.  Here and there fence lizards and side blotch lizards scurry abruptly across patches of orangey dust leaving sharp trails in the fine powder that flies up from beneath their feet and whip-lashing tails.

Only the flies and ants are active; green bottle flies, landing to steal a lick of sweat from my arms before I shoe them away and inexhaustible armies of red ants collecting seeds to add to their larders.

It is the middle of the day, the time when the Chumash sun god grows weary of carrying the heavy bark torch he carries across the sky and stoops under its weight, allowing the flame to fall close the the planet’s surface.

Here and there on the drably greenish slopes pillars of bright white stand proud, like blowtorches, clearly visible for great distances in the bright sunlight.

Chaparral Yucca (Hesperoyucca whipplei) 3/4 of a mile away through a 300mm lens, uncropped.

Chaparral Yucca (Hesperoyucca whipplei) 3/4 of a mile away through a 300mm lens (8.5 zoom equivalent), uncropped.

These 9+ foot (3+ meter) beacons are the  inflorescences of an iconic coastal chaparral plant and the reason why I am walking in heat that even the lizards are avoiding.

This plant has a number of common names and has recently been reclassified and renamed in the academic literature.  The most common name is simply “yucca”, with the “y” portion pronounced as in “ya-all” rather than “you”.  This is not to be confused with “yuca” (pronounced with the “you” sound), the cassava root, a common food found through much of the tropics.

This particular species of yucca is also known as Chaparral Yucca, Common Yucca, Foothill Yucca, Our Lord’s Candle, Quixote Yucca, and, perhaps the most telling, Spanish Bayonet.  I find the latter name to be particularity evocative as the long, lance-like leaves are crowned with a needle-like point that easily penetrates clothing, only to break off under your skin, leaving a mark that itches for days to weeks as your body works the barb back out.

Like many organisms, this plant has been classified and reclassified, the scientific name changing back and forth as new information comes to light.  It is currently known as Hesperoyucca whipplei, a name coined in 1892 by Georg Engelmann, but it spent many years happily living under the name Yucca whipplei, when it was thought to be more closely related to Joshua Trees than recent genetic analysis indicates that it is.  Perhaps I am lazy, but I have always referred to it as yucca, and will continue to do so, relying on context to clarify which of several I mean.

The inflorescence of Chaparral Yucca is a mighty affair, that stands high above the landscape in defiance of herbivorous predators, protected by its height and the spiky ball of needle-tipped blades below.

Unopened buds at the opt ad a yucca flower stalk

Flowers and unopened buds at the top of a yucca flower stalk

A senescent yucca with a 4 foot (3+ meter) ball of blades dying after blooming)

A senescent yucca with a 4 or 5 foot (1-2 meter) ball of blades dying after blooming)

For many years these yuccas, which are monocots (having simple leaves with no branch-like structures in them) were though to be in the lily family (Liliaceae) on the basis of their flower construction which closely mirrors the multiple sets of 3  and superior ovaries that are a characteristic of lilies.  Now the yuccas have been moved into the Asparagaceae family which includes asparagus, orchids, hyacinths, Lily-of-the-Valley, and the close relative agave, known to most people in its cooked, fermented, and distilled form, Tequila.

Superior ovaries and the parts in sets of 3 and 6

Superior ovaries and the parts in sets of 3 and 6 – this flower had fallen onto a different plant

When you look at the flowers of a plant you are looking at its genitals, a thought that should give one pause the next time you buy flowers for your partner.  Unlike animals, plants cannot wander about to seek their mates and thus many must rely upon intermediaries for reproduction.  The various colors, shapes, scents, and sizes of flowers are meant to attract very specific sexual intermediaries.  Brightly colored flowers are often attractants for birds, butterflies, and bees that are active during the day, long tube-shaped flowers attract hummingbirds and insects with long tongues, flowers with fetid scents often attract flies and beetles.  The yucca has relatively large bright white flowers with a slightly sweet, nutty smell.

Bright white yucca flowers - white flowers often attract night flying animals such as moths and bats

Bright white yucca flowers – white flowers often attract night flying animals such as moths and bats

These highly scented, bright white flowers, so visible during the day, are meant to attract night flying creatures.  In this case a very specific moth, the California Yucca Moth (Tegeticula maculata).  The relationship between the Yucca Moth and the yucca plant is one of mutual dependence; despite all the other insects that come to steal nectar, only the yucca moth pollinates the plant.  As it does so, it deposits its eggs in the developing seed pods, where the larvae grow, eating some of the seeds as they grow.  These moths only lay eggs in the yucca seed capsules.  In return for pollination (sex) the plant sacrifices some of its seeds.  At this point, neither the plant, nor the moth can survive without the other.  The specificity of the relationship suggest that it is an old one.

The yucca plant is incredibly useful.  The long leaves are tough and full of strong fibers.  The whole leaves were woven into mats and sandals.  The fibers were separated and twisted into extremely strong cord; numerous time I have done this quickly in the field when I need a length of twine and do not want to cut the cord I carry in my pocket.  The flower stalk is full of water and sugar, the flowers themselves are edible, more than edible, they are delicious with a delicate nut-like flavor with a touch of bitterness, a little like cashew blended with bitter almond topped with a dash of gardenia scent.  The unripe seeds are edible raw or roasted, and the dried seeds can be ground into flour.

It is not only humans that find the plants useful and delicious, deer, rats and birds all like to eat the tasty bits, many getting water in addition to nutrients.

Yucca inflorescence being browsed on by a hungry animal

Yucca inflorescence after being browsed on by a hungry animal

It takes a yucca plant 4-6 years to reach flowering stage, then, like a century plant, it dies shortly after flowering.  Even while it is flowering the leaves begin turning color.

Yucca basal rosette with leaves dying after plant flowers

Yucca basal rosette with leaves dying after plant flowers

New plants grow from runners and dispersed seeds.

The old flower stalks can remain standing for another year or two before collapsing, often with the shredded remains of the seed pods still attached.

Fallen flower stalk with empty seed pods attached

Fallen flower stalk with empty seed pods attached

This is one of the iconic plants of the coastal chaparral environment, one which I admire, but treat with the utmost respect, having spent far too much time digging leaf-spikes out of my legs and arms over the years.

Things that Gall – plants and parasites

The word “galling” is particularly evocative.  In its most simple form something that galls is merely annoying or vexing, but the true definition connotes annoyance taken to an extreme level.  The sort of thing that will do you no harm but rankles tremendously; much like being forced to pay taxes to support actions you object to.

For us these annoyances are mental and emotional, for plants these galls are physical but are often merely annoyances for them as well.

Dried oak apple gall  on Scrub oak in California

Dried oak apple gall on Scrub oak in California

Many plants suffer from galls and the galls are so singular in form that they can be reliably used to identify individual parasite species.  A fantastic book on identifying plant galls for the California region is the Field Guide to Plant Galls of California and Other Western States.

Oak trees seem to be particularly susceptible to parasites of all sorts and a common manifestation is the Oak Apple Gall, most often seen as a hard, woody ball dangling from a twig.  These galls are created by the Oak Apple Gall Wasp, a common name for a variety of small wasps that inject their eggs into the midrib of a developing leaf and chemically trick the tree into growing a protective shell for the developing larvae.  Despite appearing woody when dried, this type of gall is actually a modified leaf.  The delicacy of these galls is more easily seen when they are still green.

Fresh Oak Apple Gall - Virginia

Fresh Oak Apple Gall – Virginia

The developing wasps browse on the oak tissue and are often preyed upon or parasitized by other animals, including birds, raccoons, and a whole host of insects, other wasps included.  Some insects use the gall for their own protection, sharing the space with the wasp larvae.

Oak Apple Gall with non-wasp larva inside next to a Twig Gall - California

Oak Apple Gall with non-wasp larva inside next to a Twig Gall – California

Certain Oak Apple Galls, the Iron Galls,  in Europe were collected to make ink.  For 1500 years ink make from the iron gall was the primary source of writing quality ink in the Western Hemisphere.  For anyone interested Evan Lindquest provides detailed instructions on how to make your own iron gall ink.

Like may things we have a long history with there is a great body of mythology and folk-lore that has accumulated around these galls.

Many galls are hard and woody, there is a Twig Gall I sliced in half in the photo above.  It appears to be empty, but a dark brown patch filled with frass (insect excrement) can be seen winding its way though the bloated tissue.

Oak Apple Galls often fall from the tree, but Twig Galls are a more permanent fixture of the tree.

Twig Gall on a scrub oak branch flowering from the tip - California

Twig Gall on a scrub oak branch flowering from the tip – California

Right now the Scrub Oak is blooming along the coastal mountains in Southern California.  The twig galls are uniformly clustered near the tips of the branches, with many of them crowned by small clusters of flowers.  This provides a bit of insight into the formation of these and other galls.

The gall must be grown, and while the living plant cells are constantly dividing, the true growth of a woody plant takes place at the tips of the branches and roots, or at the apical meristem of each limb.  The cells in the apical meristem are undifferentiated,having the potential to become a wide variety of plant organs, much like stem cells in animals.  The parasite, be it a wasp, bacteria, or virus, co-opts these “stem” cells and gives them new instructions.  In a way the galls are akin to a tightly controlled cancer initiated by the parasite organism.

The Twig Galls I was looking at today were insect formed and, as such, the insect needs to escape the protective structure once it is mature.  Many of the galls had little holes in them showing where the little wasps has crawled out.

Exit holes in a Twig Gall - California

Exit holes in a Twig Gall – California

The variation in galls is astounding.  I have seen leaf galls on wild roses that look like tiny sea-urchins dipped in vermillion.  There are galls that not only force the plant to grow a protective structure around it, but that trick the plant into producing nectar to attract ants which in turn protect the growing larvae from predators.  Many are extremely colorful and the shapes are widely varied.

Colorful leaf galls on a Sugar Maple leaf - Vermont

Colorful leaf galls on a Sugar Maple leaf – Vermont

The common theme is that the galls are all formed in developing tissue, leaves, new twigs, flowers, roots, or fruit.

A gall on Shadbush fruit - Vermont

A gall on Shadbush fruit – Vermont

Some of the Ichneumonidae wasps that make so many of the galls we see have developed a biological metallurgy, evolving zinc and manganese coated ovipositors which they use to inject chemicals and hormones into the plants they co-opt.

The specificity and regularity of the galls and the relationships between the plants and the gall formers speaks to a lengthy and complicated evolutionary history.

We pride ourselves (or are horrified by) our newly found ability to genetically manipulate plants and animals.  In truth, we have a long way to go before we catch up to what we often mistakenly call the “humble” insects.

Into the forest at Lubuk Baji – Part 2: Monkeys and Apes

The real temperature was not so great, perhaps 83°F (28°C), but the humidity and the still air in the forest made it seem hotter.  I took large, slow strides, my toes instinctively trying to grip the slippery, steep slope through my sandals, my sleeves rolled down to keep the constant flow of sweat from dripping down my arms onto my camera bag.  A bandanna looped around my neck served as a towel to mop sweat from my face, sweat that stung my eyes, sweat that was so prodigious that it felt like the inside of my mouth was sweating.

Bird calls, the occasional ululating call of a gibbon, and the clicks and whirrs of numerous insects surrounded us.  Despite the fecund richness of the forest around us the only animal life to be seen were insects, most obviously large butterflies, predominately black in color, some with large yellow patches, others with cerulean blue patches, many with white polka-dots scattered over their wings.  In the warm air they rarely stood still, preferring to dance in the solitary shafts of sunlight and flit erratically through the trees.

Large butterflies were common in the forest, many about the size of an open hand

Large butterflies were common in the forest, many about the size of an open hand

On the forest floor, amongst the leaf litter crawled the occasional giant woodlouse, relatives of common pillbug but far larger.  They would curl at the slightest provocation, looking like painted ping-pong balls.

Giant woodlouse curled up on the forest floor

Giant woodlouse curled up on the forest floor

We were looking for wild orangutan in the hills of Lubuk Baji.  We knew they were in the area, abandoned sleeping nests in the trees and their pungent scent attested to their recent presence but they remained hidden in the forest.

Lubik Baji is a small hill on the west side of Gunung Palung National Park in West Kalimantan, Indonesia.  This large park is one of the last remaining protected lowland forests and contains nearly 10% of the world’s remaining orangutan.  The nearby town of Sukadana is partially surrounded by the park and a large number of people live nearby, many of them relying on resources found within the park for their livelihoods, especially timber resources.

Gunung Palung NP wraps around Sukadana, to the east is a small hill names Lubuk Baji

Gunung Palung NP wraps around Sukadana, to the east is a small hill names Lubuk Baji

We had seemingly missed our chance to see these large forest dwelling primates, perhaps arriving too late in the day.  Our guide kept a close eye out and several times pulled us off  the trail through small tangles of spiky rattan palm to follow up on potential sightings and sounds.  Each turned out to be a false alarm.

Wandering off the trail brought its own rewards though.

Large ground orchid in the Borneo rainforest

Large ground orchid in the Borneo rainforest

Where the ground was a bit more damp large white ground orchids grew, the broad, soft leaves looking more lilly-like than orchid like.

Unknown red & blue fruit (if you know, please let me know).

Unknown red & blue fruit (if you know, please let me know).  Each blue fruit was only about 1 to 1.5cm long.  EDIT: possibly Baccaurea odoratissima

The tree above was fruiting directly from the trunk.  This is a trait called cauliflory.  Plants that exhibit cauliflory flower and fruit directly from their stems and trunks.  It is relatively common in tropical environments and rare to non-existent elsewhere.  I have seen it on many plants in the Amazon, but the fruit growing in this manner that most people will be familiar with is papaya.  I think it is one of the most striking and beautiful ways for a tree to flower, in part because it is so unexpected.

I have heard several hypotheses for why tropical trees do this; one has to do with sun protection for delicate flowers and fruits.  Tropical sun is intense and the trees may be protecting their fruits under a dark canopy.  Another thought is that it makes the fruit easier for large animals to reach as they do not have to rick precarious trips onto thin branches that may not hold their weight.  One side effect of this growth form is that trees can produce fruits of immense size.  Jackfruit (Artocarpus spp), a delicious fruit of which there are many species, produces some of the largest fruits of any tree, the largest fruits weighing up to 80 pounds (36 kilos).

Failing to see any wild primates we continued our hike along the ridge to an overlook of bare granite shaded by a grove of tall bamboo.

Looking East-Northeast over Gunung Palung National Park and parts north from the Sukadana Hills

Looking East-Northeast over Gunung Palung National Park and parts north from the Sukadana Hills

From here we finally got an overview of the surrounding countryside.  Views like this can be surprisingly rare in forested lands, even when there are hills and mountains.  Below us rice paddies infringed on the edge of the national park, then faded into a shaggy carpet of greenery.  Here and there eskers of logging tracks could be seen following stream courses and through binoculars it was clear that all the tall trees had been cleared from the lower slopes of the distant hills.

We sat enjoying the breeze and view for a time, then headed back to the stream and park building for lunch.

I grew restless and maybe 15 minutes before we were to set out I told the guide that I would go first and wait for the rest of the group later on.  Walking in nature in large groups always bothers me a bit, too many people talk too loudly, make too much noise moving through the forest, and scare off the wildlife.  I tend to walk slowly and quietly with frequent pauses to listen, look, and smell the air.

As it has so many times in the past my slow approach to nature paid off in spades.  Just downhill from the honey gathering tree I saw a large branch move across the stream and head a loud rustle, clearly not from the wind.  I froze and waited, watching the closely.  Large dark shapes clambered about, difficult to see, sometimes in deep shade, other times so strongly backlit by the sun that all I could see was a dark blob.

I waited with my camera out.  After a few minutes of quiet waiting the orangutan began moving about, foraging and breaking off large dead limbs.  I waited until they seemed accustomed to my presence, then slipped back up the trail to wait for the rest of my hiking group.  Five minutes later they came down the trail, talking and breaking dead branches on the ground.  “Shhh, tiga orangutan,” I said holding up 3 fingers.  Everyone fell silent and we crept down the hill.

The orangutan watched us for a few minutes, then returned to foraging.  One adolescent clambered directly over us, occasionally peering down through the sheltering leaves, then moving on again.

Very curious adolescent orangutan

Very curious adolescent Bornean orangutan (Pongo pygmaeus)

Most of my photos did not turn out well, the contrast was too great and the apes moved too quickly.  After much post processing one image revealed that there were at least 4 orangutan, possibly more nearby.

After about 20 minutes we continued on our way down the hill, pausing to swim in a deliciously refreshing pool at the base of a waterfall.

The trail was paralleled by a series of lovely waterfalls

The trail was paralleled by a series of lovely waterfalls

Regretfully donning our clothes once more we continued our hike out of the forest, happy at seeing the orangutan and thinking that out wildlife sights were at an end.

Just inside the margin of the forest we found that we were unexpectedly and happily wrong.

Red leaf Monkey (Presbytis rubicunda), aka Maroon Leaf Monkey

Red leaf Monkey (Presbytis rubicunda), aka Maroon Leaf Monkey

Several Red Leaf Monkeys were foraging for fruit in the semi-wild durian orchard.  They made long, graceful leaps between the trees, their tails streaming out behind them, accenting the arc of their flight.

People often think we need to protect the forest in order to protect species like the orangutan, various monkey species, birds, and other forest inhabitants.  While this is indeed true, it is only part of the picture.  The forest denizens must be protected as well because without them the forest changes, sometimes radically, becoming a completely different environment.

Many species of plants require their seeds to be consumed along with their fruit and carried far off as part of their dispersal strategy.  Many seeds must pass through the digestive tracts of specific animals before they will germinate.  The extinction of one animal species can have repercussions that are slow to manifest, are difficult to reverse, and may have a wider impact through the ecosystem.

We often talk of specific species as being keystone species.  It may be wiser to think of all species as being keystone species.

Red Leaf Monkey watching me

Red Leaf Monkey watching me

Away Dog! Apocynaceae, the Dogbane family

Near my house, next to the road the ground is sandy with a scattering of pebbles in the mix.  Like much of Vermont what is not bedrock is ground up glacial debris deposited when the vast continental glaciers melted away.  The ground is sandier than most places at my house because I am perched on the southern slope of a small rock outcrop, a place where the downward pressure of the glacier was lighter, water flowed under the ice, and fine sediment was deposited.

In that sandy ground there are wild strawberries, mosses, dandelions, fleabane, hay scented ferns, a few coneflowers, some potentillas, Allegheny blackberry, a little bracken fern, and a small stand of dogbane (Apocynum cannabinum) with delicate pink flowers.

Hemp Dogbane (Apocynum cannabinum)

Before moving to Vermont my only experience with this plant was via books.  I always wondered why it was called Dogbane.  Was it like negative catnip for dogs?  Or was it simply toxic to dogs?  Apparently it is a toxin, and not just to dogs.  Ingestion of any portion can induce cardiac arrest and both the family and genus name literally translate to, “Away Dog!”  Apocynum cannabinum has, thick, milky sap, much like a milkweed, indeed Milkweeds (Asclepiadoideae) are now considered to be a subfamily of the Dogbanes (Apocynaceae).  Other members of the Dogbane family include two of my least favorite plants, Oleander and Vinca, both from the Mediterranean and common in California where they were introduced as ornamentals.  Oleander can be seen in any urban environment in Southern California, most often as a highway divider plant.  The sap is extremely toxic, raising painful rashes, and the smoke can be lethal if inhaled.  Vinca, more commonly known as periwinkle, is  common in Northern California where it invades riparian areas, covering both ground and small trees in a dense, vining mat of glossy green leaves studded with pretty blue flowers.  It is nearly impossibly to eradicate once in place.

In the past some Apocynaceae species were used to make a poor quality rubber, others for toxin to apply to arrows.  Some species produce edible fruit and others edible flowers.  We extract heart drugs from a few of them as well.

The dogbane in my yard, Apocynum cannabinum, is a traditional North American source for extremely strong fiber, hence the “cannabinum ” species name, referring to the hemp-like characteristic of the plant.  Common names run from simply Dogbane, to Indian Hemp, Wild Cotton, and Hemp Dogbane.  The fibers are stripped from the stalk in late fall and can be twisted into a fine, strong cord.  Cords made from dogbane were prized for their great strength and used for sewing, fishing lines, and other work requiring fine cordage.

The Hemp Dogbane ranges from calf high to chest high.  The ones in my yard top out at waist high.  The have an odd branching structure, perhaps best described as irregular opposite.  The main stalk continually divides in a binary fashion, with one side acting as a dominate leader, this pattern is often repeated on the side branches, but in some cases buds on both side of the stem will form side branches instead.  The result is a roughly Y shaped plant that rapidly spreads as it grows.

Apocynum cannabinum whole plant.

The leaves are opposite and the undersides are covered with a fine pubescence.  I expect that the hairy leaves are an adaptation to help cope with moisture stress.  Plants often evolve this trait to create a boundary layer of trapped, still air that aids in preventing moisture from being blown away.  The upper leaf surfaces have a matte waxy texture, a little like nasturtium leaves.  Water beads and runs off of them rapidly.

Apocynum cannabinum leaf hairs

The seeds are held in long, horn-like pods.  This time of year few of the seed pods have developed, but a couple of plants are a little further along in the cycle than others.

Apocynum cannabinum seed pods, not fully developed

Few of the leaves have any insect damage, but the flowers are popular with a number of insect species.  I’ve seen ants, flies, bees, and moths going to them.  Hidden amongst the flowers are predators as well.  The Goldenrod Crab Spider (Misumena vatia) seems fond of my dogbane.

Goldenrod Crab Spider (Misumena vatia) playing parlor games with a fly

Goldenrod Crab Spiders are so called because they often hide amongst the bright yellow flowers of goldenrod, a common meadow plant in New England.  The spiders change color from white to yellow and back again based on input from their eyes.  The yellow color seeps up to stain their carapace, providing camouflage.  When they move to a pale flower the production of this pigment stops and the spiders slowly turn white once more.  Experiments show that the spider will not change color if it cannot see what color plant it is on.

These are not web building spiders, they are ambush hunters, grabbing unsuspecting prey in their wide arms.

The smell of the flowers is odd and difficult to describe, incorporating many scents including a dusty sweetness and a faint rankness like dried meat on the edge of going bad, but they are pretty.