Being a flower

The first day the tram was running, a friend and I went up to try the trail on Gold Ridge. We didn’t get very far, being unwilling to cope with lots of trail-covering snow, and settled instead into a sheltered spot, out of the wind and in the sunshine, for a little picnic.

The false hellebore (= corn lily) was just poking up above the ground in snow-free areas, and fox sparrows and robins were singing. Especially enjoyable was the cheerful sight of yellow-flowered Cooley’s buttercup (now known as Cooley’s false buttercup), which some fastidious taxonomist has decided is no longer a ‘true’ buttercup (genus Ranunculus) but rather a poor cousin–a ‘false buttercup’—in a different genus.

Cooley’s false buttercup. Photo by Kerry Howard

I doubt that the wide-open flower of this (former) buttercup has a special kind of pollinator. It is probably visited by several types of insect, from bumblebees to flies and beetles, some or all of which could be effective pollinators.

Looking at those flowers, however, gave rise to a train of thought in my messy brain, starting with the question of what a flower does and the varied problems a flower has to solve.

The most fundamental function of a flower is sexual advertisement, sometimes flagrant, sometimes coy. The advertisement is commonly visual—colored petals (visible and sometimes UV wavelengths) or petal-look-alikes, pollen-bearing stamens (the male parts, often displayed conspicuously), multiple flowers bunched together to enlarge the floral display. Less accessible to humans but often an essential component of advertisement is aroma, appealing to the scent organs of various animals—in our region, chiefly insects. Nectar, and pollen itself, serve as pollinator rewards for visiting a flower.

Traditional botanists measured the reproductive success of plants by seed-set—the female function of flowers. That view of course neglects the (in most cases) necessary role of males in pollination and seed production, and the fundamental biological fact that plants can pass on their genes through both male and female functions. Passing on genes is all that counts in the evolutionary game! (Finally recognizing the importance of male function is, in effect, male liberation!)

Most flowers contain both male and female parts, although sometimes the sexes are in separate flowers on the same plant or on different plants. When males and females are separate, we sometimes see that the male flowers are bigger or more numerous than females, suggesting that more or bigger petals are very important for male function (i.e., sending pollen to the female flowers) in those species. This observation led to the idea that male flowers are competing with each other for the privilege of siring offspring, as often happens among male animals. It also became clear that showy petals could serve one gender-function more than the other, even in flowers that contain both, but this takes some clever experimentation to figure out.

There are several further complications to understanding why a floral display looks (or smells) the way it does. One factor is the availability of resources. In the case of our local fern-leaf goldthread, any given individual can switch from being entirely male, with only stamens, to being both male and female (hermaphrodite). If an individual contains female parts and produces fruit, that is a costly process, and that individual is not likely to produce female parts or fruits the next year; instead, it will produce only stamens and function only as a male. In this case, individuals are flexible, and can switch from one role to the other. In other cases, the response to resource limitation is genetically fixed, and whole populations exhibit resource-saving traits. For example, making a flower costs a lot of water (to expand the bud into a full flower), and in drier regions, populations of certain species conserve water by making smaller flowers.

Herbivores can exert tremendous pressure on flowers, sometimes in conflict with pollinator attraction. In wild strawberries, for instance, pollinators prefer large flowers, but so do destructive weevils, leaving the plant in a tight spot: make big flowers to attract pollinators or small ones to avoid the weevils? In certain species, flowers that are colored by anthocyanins (reds, purples, pinks) are better at deterring hungry insects, and where herbivorous insects are very common, whole populations of such species have anthocyanin-colored flowers instead of pale ones, which are found where the herbivores are scarce. Just how this works is unclear: There might be some direct protection by the pigments, or there may be an association between the genes for flower color and the ability of the plant to defend itself, or perhaps the same chemical pathways are involved in both. More to be learned!

In some cases, flower color is associated with the competitive ability of the plant. Certain colors are expressed where competition for space is intense, and others where competition from other plants is weaker. Apparently the same genes, or at least associated genes, control both aspects of the plant.

That is just a sample of the complex set of factors that can contribute to determining the floral display of a plant. I don’t mean to imply that all of them are operating in every case, but they (and others) need to be considered in understanding floral biology. These complexities are greatly understudied.

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August Notes

As we wended our way up Gold ridge, en route to Gastineau Peak, we noted some quivering leaves near the ground. Pretty soon, we could discern a slender, furry body moving deliberately from plant to plant. Then a small head with a white eye-ring poked up near a stem of northern geranium, nipped off the fruit, and munched up the seeds. This red squirrel was a long way from any trees, but it was systematically depleting the geranium seed crop, just as if it had come there for that purpose.

The fruit of northern geranium is so distinctive that the plant is sometimes known as ‘cranesbill.’ It consists of a relatively tall spike (roughly an inch tall), at the base of which there are up to five attached knobs, each containing a seed. When the fruit matures and dries, a hinge at the top of the spike loosens abruptly. The spike then splits into several longitudinal sections that flip upward very rapidly. This action elevates the knobs almost explosively, flinging the seeds outward (like an underhand, backhand throw). I know from experience with another species of geranium that the force of the throw is enough to fling the seeds at least twenty-five feet, if unimpeded.

This mode of seed dispersal is called ‘ballistic dispersal. It is found locally in lupine, whose pods twist open forcefully, violets, and impatiens, which is sometimes called ‘touch-me-not” for the way in which the seed capsules pop open. The champion of the ballistics mode, however, is probably a tropical tree called Hura crepitans. The tree makes rock-hard fruits a couple of inches in diameter; the fruit splits into sections (like an orange) when it is thoroughly dry. With a mighty pop, the seeds fly in all directions at high velocity, rattling against the surrounding vegetation. The trick is to bring a few fruits home, put them on the kitchen table to dry, and wait. Then, when no one is mentally prepared, they will go off, startling the daylights out of every creature within earshot, and ricocheting all around the room.

That was a long digression from Gastineau Peak, but I couldn’t resist recalling the fun that Hura’s fruits provided. That was many years ago—these days they might just give me a heart attack.

The route up Gold Ridge provided a good floral show at the higher elevations, including gentians, monkshood, and some still-flowering geraniums. In some dense salmonberry thickets we heard muttering and clucking and peeping, so we knew there had to be a family of grouse lurking under the leaves. Only after we passed by did the hen and big chicks flutter up and over the trail into the brush on the other side.

From Gastineau Peak we looked down into Icy Gulch, where three mountain goats reclined on a green knoll. There was a stiff, chilly breeze that sent us into the lee of a small side ridge for lunch, but the ravens were enjoying it thoroughly, showing off their aerobatic maneuvers.

On another day, a friend and I came down the Fish Creek trail, just because we hadn’t walked it for a long time. Aside from a prodigious mudhole filled with a deep, sloppy, viscous mess (which we reduced somewhat by using some primitive engineering), the most notable observation was the horde of pink salmon thronging the stream up the barrier falls. The banks were littered with long-dead chum salmon, largely intact except for missing eyeballs. The ravens had been foraging selectively for the choice bits of fat that pad the eyes. Dozens of ravens were still there, including what sounded like over-grown but lazy juveniles clamoring for food delivery from their parents. But no eagles.

Strangely, there was no bear sign along the trail, despite the dense crowds of pinks, until we reached the highway bridge. There we found one bear scat—full of blueberry remnants. This begs the question: Why were bears seemingly ignoring the stream full of salmon?

April

The ice is just starting to melt on my home pond, so there is a little open water at both the inlet and the outlet. As soon as there were a few square yards of open water, a pair of mallards moved in. They rested on the edge of the ice, dabbled in the shallows, and gobbled up sunflower seeds spilled from the feeders that hang over the pond.

Then one day I noticed quite a kerfuffle out there. The female was hard to see, posed rather flat on the water. The male was very excited, vigorously bobbing his green head up and down, and splashily diving near the female several times. Quite a showy preamble! Then he was on her back, nipping the back of her neck, and they were doing the mating thing.

She will probably lay seven to ten eggs and incubate them for about four weeks. So, if she and her eggs are lucky enough to avoid predation, I may see ducklings on my pond in due course.

A stroll to Nugget Falls yielded the first purple mountain saxifrage of the season, blooming considerably in advance of others in the area. The flowers of this species are usually female, with receptive surfaces for pollen, before they become functionally male, with ripe pollen. So this plant had perhaps lost its chances for seed production, because the flowers clearly presented mature pollen. If a bee now happens to find it and remove pollen, it would be difficult to find another plant ready to receive that pollen—unless some other plants open their flowers very soon. Maybe a bee can fly to the west side of the lake, where this plant blooms on the rock peninsula. Maybe it doesn’t pay to be TOO eager! Research has shown that seed production in the species is commonly limited by insufficient pollen deposition.

In the same area, where mountain goats have been foraging and resting for months, I finally saw a nanny with a kid, moving up the ridge into the brush. The kid was pressed close to mama’s side, so what I really saw was a white blur with eight legs (well, seven legs, actually, but you get the idea…).

Another stroll, on the wetlands, treated me to my first ruby-crowned kinglet song, one of my favorites. They’ve been here for a little while, but I hadn’t heard them for myself. Six swans on the river took off when they saw me move, even though I was still pretty far away and partly concealed. Canada geese were also quite nervous and left the meadows for the far side of the river. Even the ducks were uneasy and sailed slowly away downriver (mallards, goldeneyes, ringnecks, buffleheads, green-winged teal). Sadly, I missed the mountain bluebirds that had stopped there on their way north.

A more strenuous outing took us, on snowshoes, up one of the forested slopes at Eaglecrest. We gained a fair amount of elevation and looked down on the upper cross-country ski loop and Cropley Lake. We watched a ptarmigan snatch buds from blueberry twigs, marching calmly from one bush to another. The first clue to its presence was a line of very fresh tracks in the fluffy snow that lay atop the hard crust.

The greatest fun concerned a raven. First, we heard a lovely little melody coming from high in the hemlocks. It was repeated several times. The song was unlike that of any other songbird that I know. So we couldn’t identify it—until one little trill was followed by a brief squawk. Then a raven flew in, carrying a stick, disappeared briefly, and then flew back the way it came. Back and forth it went, with a rush of air in the wing feathers, each time bringing a stick. All the sticks were about the same size, maybe a foot long or so. After the bird had made several trips, I finally spotted where the sticks were going: high in a hemlock, in a snug spot next to the trunk, was a dark lump. The next two times the busy raven arrived, we could watch it work the sticks into the existing structure. This raven was still building the nest exterior, a bit behind the others that I’ve watched, which have been gathering and carrying dry grasses for nest lining.

Ravens are technically songbirds, along with sparrows and warblers and thrushes, although that comes as a surprise to many folks. On this day, ‘our’ raven earned its technical classification, with it short, sweet, melodic song.

Then, on a fine, blue-sky day, Parks and Rec sashayed, in shirt-sleeves, up to Spaulding Meadows. We didn’t even need snowshoes until we reached the upper meadow, because the trail was well packed. This trail is far easier to negotiate in winter than in summer, because the myriad mudholes are frozen and snow-covered. The upper meadows looked like the skiing would be wonderful, and the two skiers that started out with the rest of us plodders soon disappeared and were not seen again that day. Just before the top, we found some tracks that I think were made by a pine marten. We perched on a snowbank for lunch, shielded from a little breeze by a stand of trees, and thoroughly enjoyed a view of the sunlit peaks around the glacier.

Around Cropley Lake

Ambling up from Eaglecrest to Cropley Lake at the end of July, we passed from summer back into spring. Near the lodge, the tall blueberries were ripe, attracting batteries of pickers with buckets. Just a few hundred feet higher, the low-growing bog blueberries sported their tightly closed pink buds. By the lake, flowers were still blooming while at the lower elevations, the same species had set seed. The tiny white gentian, however, dotted the meadows almost everywhere.

We found several stands of the pretty shrub called copperbush. It’s related to blueberries, but you wouldn’t know it from appearances. The flowers look entirely different: they have spreading, coppery petals instead of the pendant, pinkish-white bells of the blueberries, and the fruit is a dry capsule, not a succulent berry.

I don’t know how long Cropley Lake has been there; a small pond may have occupied the bowl originally. One drainage was blocked by a dike, decades ago, judging by the size of the spruce trees on its crest. A dam was built across another drainage, and the overflow from the dam feeds a small pool, which drains down-valley to help create Fish Creek.

We sat on the boulders just below the dam, watching the miniature Dolly Varden foraging on surface insects. They ranged in size from four to eight inches or so. Many of them had colorful orange fins, and we guessed that these were males. They could be mature individuals, despite their diminutive size.

The resident Dolly Varden in Cropley lake were undoubtedly introduced by humans many years ago. Resident Dolly Varden, which live their whole lives in fresh water, mature at a small size. A tiny female may produce only a few dozen eggs. If some of their offspring get washed downstream to the sea, they may survive and adopt an anadromous life style: growing to a large body size and re-entering fresh water to spawn. But return to Cropley Lake can’t happen; there is at least one barrier falls.

The dollies we saw in the pond below the dam may be in for a hard time, come winter. The pond must often freeze right down to the bottom, or nearly so. In past springs, I’ve sometimes seen several dead dollies here, with no living individuals in sight.

On the other side of Cropley Lake, we found a stand of creamy-flowered plants growing near a seep. They looked rather like fireweed, except for the flowers. I think I once knew them, but–as with so many things—the knowledge had faded. However, our handy plant guide told us that they are indeed yellow fireweed, more of a habitat specialist than our common pink species.

I was pleased to find numerous butterwort plants, a.k.a. bog violet. The purple flower is vaguely violet-like, but the nectar spur at the back of the flower is much longer and the face of the flower is distinguishable upon close inspection. Butterworts are insectivorous plants; their flat yellowish leaves are sticky traps for insects, which are then digested by the plant. The insects are a good source of nitrogen for plants growing in boggy, nutrient-poor soils.

Butterwort. Photo by Bob Armstrong

We also inspected the stems of the little iris relative with the ponderous name of sticky false asphodel. The flower stem is covered with sticky hairs that trap miniscule insects. Some years ago, we did experiments to see if this plant could be insectivorous, putting chemically labeled fruit flies on the sticky stem and then testing for presence of the label in the plant’s seeds and roots. No luck. There may be another function of the sticky hairs that remains to be discovered.

For those interested in the names of things: the true asphodel is an Old World lily (not an iris) and it was the flower of the Elysian Fields in Homer’s Odyssey. These fields were the meadows where dwelt the souls of the dead. (The name ‘asphodel’ was also strangely corrupted into ‘daffodil’, a totally different plant.) The famous Parisian avenue called Champs Élysées means Elysian Fields, presumably referring to the gardens that once flanked it and not to a collection of dead souls!

Bumblebees

In early spring, I look forward to seeing the first bumblebees, visiting willow catkins and early blueberry flowers. These ae queens, which mated last fall and then hibernated, each one usually in a small chamber she dug in the soil. Bumblebees can regulate their own body temperature by shivering (as can dragonflies and hawkmoths), and so they are able to be active when many other insects are immobilized by cool temperatures.

The springtime queens find sites for their nests, often using abandoned mouse or vole nests. They need the insulation provided by the fur, dry grass, moss, and feathers that the rodents gathered, but they may also drag in additional material from nearby. In each nest, a queen builds a wad of pollen on which the eggs are laid and the larvae will feed; she also builds a tiny nectar pot where she stores nectar for herself. The queen incubates her brood and feeds the larvae on regurgitated pollen and nectar. Total development time from egg to adult bee takes four to five weeks. The first brood of the season is typically small, fewer than twenty eggs; later ones may be larger, because there are then worker bees to help raise them.

Digging a nest. Photo by David Bergeson

Newly emerged adults are mostly workers; some stay in the nest to help tend the next brood and other become foragers, gathering nectar and pollen to feed the growing colony. Different kinds of flowers provide different quality (and quantity) of nectar and pollen: some nectars are rich in sugars and may differ in the specific sugars provided. Pollens also differ among flower species, with some (for example, legumes such as lupine and beach pea) having higher protein and different amino acid composition than others (such as roses and blueberries).

Foraging bumblebees can be quite selective in their choice of flowers, and the more well-stocked the nest larder, the more selective they become. They learn to use visual cues such as color and shape, and respond to the level of food reward (nectar or pollen) offered by the flower: flowers that offer high rewards are visited more often. And they learn how to handle different kinds of flowers, some of which hid the nectar or pollen deep inside a complex structure (think of lupine or monkshood) that requires a bee to manipulate the flower in a certain way to gives access to the food reward and achieves deposition of pollen and transport of pollen to another flower.

Foragers also learn to use scent cues, provided by the flower and by other bees. Foraging bees can leave scent marks on flowers they’ve visited, cuing other workers to avoid the depleted flower. When successful foragers return to their nest, they can signal their success to other workers. The returning forager runs around the nest excitedly and releases particular scents that stimulate other workers to search for the floral scent carried by returning bee. Unlike the more famous honeybees, however, bumblebees don’t signal the direction in which the food source was found.

Later in the summer, queens (and in some cases, workers too) begin to lay unfertilized eggs, which develop into males. The males do little around the house, so to speak, but sally forth to feed and look for mates. Males of many species establish a scent-marked route through their habitat, leaving their scent marks on selected sites such as rocks or tree trunks; they then patrol the route in hopes of attracting females. Other species set up small territories and perch there, defending their chosen spot from other males and waiting to accost a passing female. The females of interest are newly emerged queens; when mating is successful, the new queens go on to find hibernation sites in which to await the coming of spring. The workers die off and our new queen bumblebees may have gone to bed by now.

Many hazards threaten bumblebee colonies. Domestic colonies of bumblebees spread disease to wild populations. There are predators and parasites, of course, and environmental hazards such as flood, habitat destruction by humans, pesticides, and so on. In addition, occasionally the balance of power between a queen and her workers shifts, and the workers kill their mother; they may then rear their own sons (from unfertilized eggs). Sometimes a late-emerging queen who fails to find a good nest site turns assassin, invading a recently established nest of the same (or closely related) species, killing the resident queen if possible, after an intense battle, and usurping the brood of workers to rear her own offspring.

There is a distinctive type of bumblebee called the cuckoo bees. They are tougher and have more powerful stings than regular bumblebees. They make their living by invading young colonies, killing the queen, and usurping the old queen’s position in charge of the colony. The invader may kill and eat the host’s eggs and larvae; any surviving workers rear the invader’s offspring, all of which will be males or future queens of the invader’s species (the host nest seldom produces queens after it has been invaded by cuckoos).

Here in Southeast, a recent publication indicates that we may have about seven species of bumblebee (of over forty in North America), including one species of cuckoo bee. They are essentially impossible for non-experts to identify without killing the specimen. The easily visible banding patterns of yellow and black and sometimes red are remarkably variable over the range of a species and can vary even within more limited areas.

Difficult to identify but fun to watch: what flowers are being visited, how does the bee handle the flower, how long does each visit last, does a given bee visit more than one kind of flower and if so, where on the bee is the pollen deposited. The questions are many.

A cautionary note: Be nice to our bumblebees! Many populations of bumblebees are declining, rapidly in some areas. But we need them to pollinate our flowers! Without good pollination, there would be poor fruit crops, hungry bears and birds, much less jam and pie– a very sorry state of affairs!

Dragons and Damsels

A few days ago, I stood beside a small pond, watching showy insects zoom around. There was a small blue damselfly, checking out the weeds in the shallows. And there were two of its larger dragonfly cousins: a couple of big darners and several smaller emeralds, so-named for the intensely green eyes and greenish body of mature adults.

There are over 30 species of dragonflies and damselflies in Alaska, and in Southeast we have around 19 species (3 damsels and 16 dragons). As they become better studied, more species will probably be added to the lists. The state dragonfly is the four-spotted skimmer.

Dragon- and damsel-watching is an increasingly popular recreation. Even without bothering about taxonomic details and the minutiae of species identification (which commonly requires having the creature in hand), the behavior of these conspicuous insects can be fun to observe.

My own introduction to this group, collectively called odonates (”toothy”), came several short eons ago, when I was a graduate student. I was studying yellow-headed blackbirds in the marshy potholes of eastern Washington, where these birds, along with red-winged blackbirds, were abundant. Perhaps the most important prey the blackbird parents fed to their chicks were recently emerged odonates.

Odonate larvae are aquatic predators, capturing prey with a huge, extensible, hooked lip. They may spend a year or two, or sometimes more, in the water, feeding and growing.

Damselfly larvae breathe by means of three external gills at the back end of the slender body; the gills also help in swimming. Dragonfly larvae have internal gills, and they breathe through the back end of the digestive tract.

When they are ready to become adults, the larvae crawl up on a plant stem or rock, the larval ‘skin’ or exoskeleton splits open, and the new adult pulls itself out. Blood is pumped into the long abdomen and into the wings, which gradually expand and slowly harden. These newly emerged adults are called tenerals. They fly very weakly until their body and wings harden. So this is the stage of their life when they are extremely vulnerable to predators, such as the blackbirds. The blackbirds I was observing stuffed their chicks with tenerals all day long.

As fully mature adults, odonates are much harder for birds to catch. Odonates have four wings, which can be moved independently of each other, giving them great maneuverability in the air. Adult odonates are terrific predators of other insects, catching the prey in a basket formed by their spiny legs, and munching them up in strong jaws. They have huge eyes of multiple facets, which are fine motion-detectors. Some odonates hunt by almost constant flying and searching, and others are sit-and-wait predators, perching on a lookout spot and darting out after a passing bug.

Each adult flies for only a few weeks. During that time it forages and plays the mating game. Males of some species are territorial, defending part of a pond from other males, and waiting for females to visit. Others cruise around, looking for potential mates.

The mating process in odonates is unique among insects. The male produces sperm, which he transfers to a special chamber at the front part of the abdomen. He does this by bending forward and placing the tip of his abdomen at the entrance of the storage chamber. When he finds a female, he grabs her with special appendages on his ‘tail’, holding her by the top or back of the head. The pair may fly around in tandem for a while.

Bluets mating. Photo by Bob Armstrong

The female then loops her abdomen forward to connect with the special sperm storage chamber. In this circular or ‘wheel’ position, a pair may fly around some more. The sperm are transferred to the female, where they fertilize her eggs.

But that’s not all: females can mate with more than one male. Competition for females is intense, and males have a nifty way of beating out competitors. Their penis does more than transfer sperm. It also can remove or push aside the sperm of males that mated with this female previously. So, if this male is the last one to mate with her, he ensures that he is the father of her eggs.

In some species, the male stays with the female, either in tandem or nearby, keeping guard on his paternity while she lays the eggs. In other species, females just sneak off on their own and try to avoid getting grabbed by other males. Given what goes on in many birds and mammals, I have to wonder if some females might not let themselves get caught by a new male, if he looks like a better specimen and potential father.

Females lay their eggs in several ways. Some typically insert their eggs into plant tissue, using a sharp structure called an ovipositor (egg-placer). Other species just drop their eggs into water or dap them onto mud or moss.

It is easy to observe territorial aggression, tandem and wheel flights, and sometimes oviposition in these insects. Such behaviors are often easier to watch in odonates than in many birds.

Here are three nice introductory guides to odonate watching:

Dragonflies of Alaska (second edition), Hudson and Armstrong;

Introducing the Dragonflies of British Columbia and the Yukon, Cannings;

Dragons in the Ponds, Armstrong, Hudson, and Hermans (for children).

Going to the dredge islands

On a fine low tide in late April, I headed out to some of the dredge islands in Gastineau channel, along with two friends. Before we even got to the islands, we found several interesting things. In the middle of the dike trail lay the feathers and other remains of a dead bird. Grazing on the innards were at least twenty little brown slugs—officially known as reticulated tail-droppers. We often see them on bear scats filled with digested vegetation, and gardeners make war on them when they attack some treasured plants, but what were they getting from bird guts?

Just as we left the dike trail, our attention was drawn to a pinkish blob lying in sparse grass. A second look told us it was on octopus, stranded by a recent high tide. An octopus has no business being up in the grass, so after determining that it was still alive, we carefully put it in a plastic bag (from which it tried to crawl out, of course) and carried it with us until we reached some permanent salt water, where it was released and slowly crawled away. It may not have been in very good shape by then, and maybe some disability accounted for its being washed up into the grass, but at least it got a second chance.

The octopus tries to escape its rescuers. Photo by  Katherine Hocker

One island of this chain of islands was a real island before the channel silted up; its core is a forested ridge of bedrock, now surrounded by uplifted land that supports a ring of small spruces and elder berry bushes. An exploration of this island turned up two bird skeletons, minus the skulls; a little forensic work later determined that the bones were very likely those of bald eagles. That made us suspect that they had been shot and left to rot. A sorry thing!

Under some of the trees we found burrows that looked like old otter dens, probably made back in the days before post-glacial uplift increased the distance to permanent water. A cast-up pellet of undigested bits, probably from a raven, held—of all things—the better part of the bowl of a plastic spoon. Overhead, a group of eagles and crows circled peaceably.

We flushed several snipe from the sloughs that cross the wetland. A female harrier coursed in and out of the trees on the smaller islands, probably on her way north (although harriers do nest here occasionally). And buttercups were starting to bloom along the edges of the spruce groves.

Best of all were the lichen gardens on the smaller islands, which are made of dredged sediment from the channel. Sometimes called lichen ‘barrens’, these gardens are barren only of trees and shrubs and tall herbs. They can be a wonderfully artistic spread of color and form. The lichens were very happy, owing to recent rains, so we spent some time admiring the natural art show. We also tried very hard to place our feet where they would do the least damage. Each of these gardens of miniatures was surrounded by a ring of young spruces, lending them a feeling of seclusion and privacy.

On the way back to the car, we spotted a little group of five snow geese, busily grazing—the last reward of a profitable excursion.

Late August in Granite Basin

The day began under gray skies, but by midmorning the sun was lightening everyone’s mood. A sizable group of Parks and Rec hikers, including several visitors, headed up Perseverance Trail with plans to turn toward Granite Basin, a favorite destination of many locals.

Despite a few heavy rains in the past weeks, the trail was mostly clear of mud. A month before, the thick remnants of an old avalanche had extended over a piece of the trail and the creek. The snow pack did not melt away in the past two summers, so in July, we clambered over a heap of accumulated snow. But by late August, that old snow was gone, except for a small ledge.

The wrecks of alders and other shrubs littered the slope above the trail where the snow had lain, but many mutilated trees had produced a few late leaves. If they can get an earlier start next summer, before too long the slope may again support a cover of brush to make homes for warblers and sparrows.

Two marmots cuddled together on top of a big boulder, basking in the sun. Several clusters of mountain goats dotted Juneau Ridge. A few warblers flitted through the alders, stoking up their reserves for the coming migration. Copperbush still had a few flowers, but most of the flowers had made fruits that looked like tiny pumpkins with a handle (the remaining female part of the flower).

Copperbush. Photo by Kerry Howard

There were quite a few ripe salmon berries—rather surprising in view of the many people who use this trail. Both red and yellow-orange fruits were fairly common. For the record, although there’s a myth that the red ones taste better than the yellow-orange ones, in fact the sugar content is equal. Blind taste tests with fully ripe berries showed that humans could not distinguish between the two colors by taste. We did a little berry-foraging for ourselves. So had a grouse or ptarmigan, because we found a scat in the trail was filled with salmonberry and blueberry seeds.

Wild flowers of several sorts still bloomed along the trail, and the native species of mountain ash bore its bright red fruits. A dipper searched along the edges of the pool at the entrance to basin and swam in the shallows after aquatic insects. The dippers’ customary nest site below the big waterfall had been under snow for the last two springs and was therefore unusable, but they may have nested in another site up on the back side of the basin.

Bears had wandered along the trail, leaving scats with seeds of devil’s club and vegetation fibers. Beside the trail was a wide swath of matted, broken stalks of false hellebore (a.k.a. corn lily), where bears had apparently gone after the basal parts of the plants. According to a hiker with extensive experience as a hunter, bears really do eat this plant. Although it is known to be very poisonous to humans, it’s not the only noxious (to us) plant that bears eat.

On the return trip down Perseverance Trail, several of us had a surprise. A female black bear with two cubs appeared in the trail. We stopped, and they ducked into the brush on one side of the trail. Unfortunately, that side was very close to the creek, with a steep drop-off, so there was no ready way for the bear family to distance themselves. Because we were in a group, we carefully passed by, speaking very politely as we did so. Mama sent the cubs currying up a tree and let us know her displeasure by rattling the bushes. That gave us a little adrenalin spike, for sure, but in reality, this bear was not being aggressive at all. She was just telling us in bear language to get lost, so she and her cubs could go on their placid way. So we did, and they did!

Nectar

Most folks know that flowers often produce nectar to attract pollinators—animals that carry pollen from one flower to another, enabling seed development. Less well known is the widespread occurrence of nectar outside of flowers, produced by ‘extrafloral nectaries.’ All nectars typically contain simple sugars such as glucose, fructose, and sucrose, amino acids, some defensive compounds to deter microbes, and various micronutrients.

Extrafloral nectaries are found on many kinds of flowering plants in over ninety taxonomic families, and even on some ferns. They occur on leaves, bud coverings, fruits, or shoots. The structure of such nectaries varies enormously, from pits and slits to tiny cups to scales and hairs and thorns to no special structure at all.

There was much debate over the function of these nectar-producing structures. Some biologists claimed that the plants were just excreting unwanted molecules. But that suggestion did not account for many facts about these extrafloral nectaries, including why they are located where they are, why the plant would want to get rid of sugars and amino acids that are needed for growth, or why—in most cases—ants and sometimes wasps or flies could often be seen sipping nectar from these sources. Back in the Midwest, I remember seeing dozens of ants crawling over the buds of my mother’s peonies and wondering what they were doing there.

Eventually, it became clear from extensive research that extrafloral nectaries usually attract ants, parasitic wasps, and even predatory mites and spiders that help protect the plants from herbivores. In a few cases, extrafloral nectaries attract insect-eating birds, which may then consume harmful caterpillars. The most common protective insects are ants that patrol the plant and attack insects that would eat leaves or flowers. Some adult wasps feed on nectar and lay their eggs on plant-eating caterpillars; when the eggs hatch, the larvae eat their caterpillar hosts. When a plant is swarming with aggressive ants or attended by stinging wasps, it may even be protected from grazing and browsing mammals.

It turns out that some kinds of plants nearly always produce extrafloral nectaries, but others produce them mainly or only when they are attacked by herbivores. If one part of such a plant is attacked, nectaries may be induced all over the plant and even on the plant’s neighbors (of the same species). That is, the volatile chemicals released when an herbivore attacks a leaf induce a defensive response on other leaves, even on other plants. (This kind of chemical communication is now known among a variety of plants.) It is cheaper, metabolically, to produce defenses only when needed, especially against intermittent herbivores, rather than maintaining them permanently.

Extrafloral nectaries are most common among lowland and mid elevation tropical plants, but many temperate-zone plants have them too. Examples include some members of groups that are represented here, such as elderberries, viburnums, iris, and impatiens, but whether or not our local representatives of these groups have these nectaries is not determined. The farther north one goes, and the higher the elevation, the fewer are the species that bear these nectaries. This geographic pattern is associated with a lower availability of ants at higher latitudes and elevations, where air temperatures are cool; they are also uncommon where soils are wet. If there are few or no protective ants (or other protectors) around, why spend energy on producing extrafloral nectaries and nectar?

Nevertheless, some plants that can develop extrafloral nectaries occur in our region, despite the high latitude (and in Southeast, the wet soils) and the paucity of ants. Members of the genus Populus (cottonwoods and aspens) are known to produce extrafloral nectaries on their leaves; indeed, there is a fossil leaf of a Populus species that possessed extrafloral nectaries on its leaves, over thirty-five million years ago. Some Populus species occur in Alaska. Quaking aspen, a tree of the Interior, has extrafloral nectaries on young leaves. On black cottonwood, which grows in Southeast, the activities of sucking (but not chewing) insects can induce extrafloral nectaries on the leaves, at least on young trees. Still to be determined is whether or not bodyguards recruit to this food source and reduce herbivory on these trees.

Surprisingly, perhaps, nectaries also occur on some ferns, including bracken fern, which can be found in some places in Southeast. Ferns don’t produce flowers, so by definition, these are extrafloral structures. They appear primarily early in the season, while the fern frond is expanding. Ants and spiders sometimes attend these nectaries and cruise around the fern, attacking small herbivores.

Spring is coming, and there is something to look for, next time you are out and about, with nothing else special to do! Look at young cottonwood leaves and at young fronds of bracken fern for small glandular structures and for any insects that might be visiting these nectaries. More eyes looking would actually be very useful!

Parasites and behavior modification

OK, so parasites are creepy, disgusting, and often debilitating (but sometimes useful!). They sneak into a host’s body through food, drinking and bathing water, air and soil, or an insect bite. Less well-known, however, is their ability to alter a host’s behavior. I’m not referring here to host behavior that is a direct response to symptoms of parasite infection, such as scratching an itch, or making a hurried dash for the bathroom, or going to a doctor.

There are much more perfidious ways that parasites affect host behavior, such that the host ceases to do its normal things and, instead, behaves erratically in ways that altogether favor the parasite, usually improving its transmission to the next host. Very, very sneaky! Here are some examples.

Parasitic fungi called Cordyceps use insects as a means of promoting spore dispersal to new hosts. There are many kinds of Cordyceps, each with its own kind of host insect. An infected ant, for example, climbs up a plant stem. Somehow, the fungus alters the ant’s brain chemistry and the ant gives up all normal ant-ly behavior and just hooks itself to the stem, never to move again. The fungus gradually consumes the ant’s innards and eventually sends out a shoot that releases the spores to any passing wisp of moving air. By forcing the ant to climb upward and stay there, the fungus has improved the chances of finding a small breeze to carry its spores away. A spore that disperses successfully and lands on another ant dooms that ant to repeat the whole process.

Flukes are a kind of flatworm, and they too can create behavior modification in their hosts. For example, one species of fluke infests certain snails and castrates them. The snails go on eating, but they can’t reproduce, and the flukes multiply asexually inside the snail. The asexual offspring leave the snail and swim around looking for a fish. If they find one, such as a killifish, they hook onto the gills, move into the blood vessels until they find a nerve, and follow the nerve to the fish’s brain. They carpet the surface of the brain and sit there until the fish is eaten by a bird.

Infected fish behave differently than normal fish—they swim jerkily, too close to the surface, and turn to expose their shiny sides to the light. They become so conspicuous that foraging herons or shorebirds are way more likely to capture an infected fish than an uninfected one. Once inside the fish-eating bird, the flukes feed in the gut and reproduce sexually; the eggs pass out in the bird’s scat and get picked up by wandering snails. By entering a bird, the flukes can then be carried to new ponds and estuaries—the whole complex life cycle is geared to achieve successful dispersal.

Or how about the lancet fluke inside an ant; it makes the ant run up a blade of grass each night until the grass is eaten by an herbivore, where the fluke can reproduce. Or the horsehair worm that makes an infected cricket jump into water where the worm can reproduce. Or the parasitic wasp that makes a spider spin a novel kind of web—a protective awning under which the wasp larva will hang its cocoon. Or the thorny-headed worm that makes an infected pillbug stay out in the open when a bird can grab it; the worm can reproduce inside the bird. Or the several kinds of microscopic parasites that clog up the biting apparatus of mosquitoes or flies, such that they have to make many bites in order to get a good blood meal, thus spreading the little parasite to many new hosts. Then there’s the virus that seems to make male rats more aggressive, spreading the virus with every ratty bite, and a micro-parasite that makes rats unafraid of cats, which then pick up the parasite from the rats.

Those are just a few examples of behavior modification induced by parasites. Long before psychologists concocted the term, parasites were already very good at it. There are now so many examples from the rest of the animal kingdom, that one really must consider the possibility that parasites might be able to modify human behavior and personalities as well. Indeed, research is beginning to demonstrate that this is so!

There is a vast number of parasites in the world and virtually every species, even some of the parasites themselves, harbor multitudes of these hangers-on. There is still much to be learned, even about basic life cycles of many known parasites and their multifarious ways. Undoubtedly, many parasitic species remain to be discovered, along with their weird and wonderful habits. There is also the intriguing possibility that we could learn from parasitic effects on human behavior and thereby discover new treatments for certain afflictions such as depression or hyper-aggressiveness.

The word ‘parasite’ comes from the Greek words, meaning ‘beside the food’. The ancient Greeks reportedly used it to refer to people who served food at temple feasts. Somewhere along the line, the word left that meaning and was (and still is) used to refer to people who curry favor with others in order to receive food or other benefits. After a very long time, the word was applied to animals and other organisms that live off of others—it took centuries for folks to figure out that there were such things as animal and microbial parasites, and that these entities were actually organisms that had their own lives and life cycles. Now it seems that parasites are an integral part of the lives of any other organisms, and we are just beginning to explore all the weird and wonderful interactions among them.