The Planarian

Posted in Insects, Nature Articles

planaria picBliss is floating on an air mattress, drifting on the shallow waters of the Eel River. Excitement is seeing a planarian undulating across the gravel.

It stared at me. I stared at it.

The planarian is a small (1/2” or less) and simple flatworm. It lives in rivers, freshwater ponds and saltwater, gliding across the bottom as it looks for prey (small worms, crustaceans) . The two eyespots are sensitive to light, which the planarian prefers to avoid. On the sides of its triangular head, the “ears” are actually sensitive to touch and to chemicals.

On its belly is the mouth. The planarian extend its long tubular pharynx out through the mouth and secretes digestive enzymes. These begin to chemically break up the prey. The pharynx then sucks up the bits. These go into a simple gut. The intestinal cells lining the gut complete the digestion. Nutrients are dispersed throughout the body by a highly branched system of tubes. Excretory pores along the sides release the chemical waste products.

Planaria breathe through their skin, receiving oxygen and releasing carbon dioxide. They move by the beating of small hair-like projections from the cells on their bellies, or via muscle contractions. The muscles are a part of the body membrane. The nervous system is very simple: two large bodies of nerve cells (ganglions) behind the “ears”, and nerve cords and smaller ganglions in a ladder-like configuration down the body.

They are hermaphrodites, having both testes and ovaries, but they must mate to reproduce, exchanging each other’s sperm. The eggs develop internally, are shed in capsules, and several weeks later hatch into mini-adults.

So why was I excited to see one? The last time I saw one was in a biology class, in a petri dish, where it was being cut in half. Planaria have the amazing ability to regenerate missing parts. You could cut one up into over 100 pieces and each one would grow into an intact, fully functional planarian. How does this happen? About one fifth of the cells in its body are stem cells, capable of making any of the various tissues and organs, much as the cells of an early embryo (embryonic stem cells) can do.

Today, researchers studying planaria have identified a protein, TOR, which is essential for regeneration. Without it, no growth can occur. Researchers are looking for ways to inactivate TOR in cancer cells, to stop them from multiplying and to activate TOR where needed to stop degeneration caused by disease or Alzheimer’s.

Eve Broughton was educated at UC. Berkeley and lives in Whitethorn.

 

The California Slender Salamander

Posted in Amphibians and Reptiles, Nature Articles, Uncategorized

Slender California SalamanderIt may look like an earthworm but Batrachoseps attenuates is a miniscule salamander with idiosyncrasies. Two-thirds of its total 2 ½” to 5 ½” length is tail. Its tiny head is narrow and its brown skin is deeply grooved between the ribs, thus completing the earthworm disguise. Unlike an earthworm, they have bulging, front-facing eyes, tiny arms and legs, and a tooth-filled mouth. Batrachoseps are lungless and breathe through their thin moist skin. Unlike other salamanders they have four toes instead of five on each foot. The slander salamander ranges from Washington to Baja California, preferring cool, moist woodlands, oak or conifer, with deep leaf litter and decomposing wood and bark. However they are not too picky, as they have also been found in urban gardens and roadside greenery and valley grasslands. What is essential, especially during the dry season, is a cool moist retreat, often underground in rodent burrows or under rocks or logs. They are usually dormant during the dry season. With such tiny legs, they do not travel far, probably less than six feet from home base. This, along with the fact that they are an ancient lineage suggest what DNA studies have also indicated: What is currently classified as one species, B. attenuatus, has, over time, evolved into 5 or more distinct species by gradually being separated by the building of mountain ranges and the movement of the San Andreas Fault. As scientists learn more, the new species will likely be classified. Batrachoseps can sometimes be found on wet days above ground, but they mostly confine themselves to foraging in the leaf litter, or underground in termite tunnels, earthworm holes and rodent holes. Their forward-looking eyes focus on the prey, which is then snagged with their sticky projective tongue. Prey includes spiders, mites, snails and insects, in addition to earthworms and termites. Little can be said of the sex life of the slender salamander, other than that breeding takes place from December (in the hotter reaches of its range) through January. The females deposit 5 to 20 eggs in subterranean tunnels which may be shared by several females. The eggs are surrounded by capsules connected by strands of jelly; this is presumably to keep them moist for the two months of incubation. There is no aquatic larval phase. The hatched young are miniature adults, although long-legged, short-tailed and big-headed compared to their parents. So what’s the exciting idiosyncrasy? Fish, amphibians, reptiles and birds have large, oval nucleated red blood cells (RBCs). Mammals have small RBCs without a nucleus. Batrachoseps’ red RBCs also lack a nucleus? Why? During its maturation in the bone marrow, a mammalian RBC does have a nucleus (which contains the DNA), but this nucleus is ejected before the RBC is sent into circulation. The nucleated cell is 10x larger than the non-nucleated one, even through the amount of oxygen-carrying hemoglobin is the same. Slender salamanders are extremely small, and it is thought that nucleated RBCs would cause too much friction in the capillaries and possible circulatory problems.

The X-Rated Banana Slug

Posted in Fauna, Nature Articles

IMG_1987Ariolimax columbianus lives in the coastal rainforests from southern Alaska to Santa Cruz. It creeps along eating mushrooms, leaves, animal droppings and dead plant material, converting these into nitrogen-rich droppings. In doing so, they enrich the soil and spread seeds and spores.

In some forests, they are bright yellow, perhaps with black spots. Elsewhere, they can be white, brown, or olive green. The color may depend on the diet.

On the “run”, fully stretched out, a slug can be 6” to 8” long. In a more sedentary mode, the slug is more compact, about 5” long. Like their snail relatives, slugs move on a muscular foot running the length of its body. A slime is secreted, chemically intriguing because it provides traction for the muscles to push against and friction-free lubrication for dragging the body.

The slime also protects the slug from dehydration, allows the exchange of carbon dioxide for oxygen through the skin, and attracts mates. Predators seldom attack slugs because the slime anesthetizes the moist interiors of their mouths. Garter snakes, ducks, geese, moles, shrews and salamanders may eat banana slugs. Raccoons will roll the slug in dirt to neutralize the slime before eating.

The slug’s head sports 4 antennae; the lower two sense chemicals and smells, the upper two, the eyestalks, detect light and movement. All are retractable, and if you watch closely, you can see tiny eyespots moving out to the ends of the eyestalks. On the underside of the head is the mouth, with many rows of teeth to grind the food.

Behind the head is a shield – the mantle. On the right side is a hole which leads into the single lung. Beneath the mantle, also on the right side, is the genital pore. And now we get to the exciting bits.

Slugs are hermaphrodites: each slug is both male and female, and has the organs to prove it. The male organ is almost as long as the slug, and is normally kept tucked inside the body, only to protrude from the genital pore during mating. The genital pore also leads to the female parts.

When two slugs meet to mate, they begin with a few love nips (vicious), and then curl up in a ball, so that each can penetrate the other, exchanging sperm. Fertilization is internal. This coupling can last for many hours. After that, sometimes, they merely decouple and go their separate ways. But other times, for reasons not understood (but easily imagined), one gnaws off the other’s male organ. Often, this mutilation is mutual. In the future, the resultant slug can act as a female, but no longer as a male.

Sometimes, sperm are stored until the eggs are ready for fertilization. After fertilization, the 20 or more translucent eggs are laid in dark moist places, in leaves or under logs. Infant banana slugs are really cute.

Written by Eve Broughton. Eve lives in Whitethorn and was educated at UC Berkeley

 

Western Fence Lizard aka Bluebellies

Posted in Amphibians and Reptiles, Fauna, Nature Articles, Uncategorized

Fence Lizard Bellies My brother and I filled our terrarium with blue-bellies. These lizards are alert and fast but we had a secret weapon: a fishing pole. We tied one end of fishing line to the final loop on the pole, made a noose and ran the line to the base of the pole. We sneaked up on the lizard from behind, lowered the noose over his head and gently tightened the line. Capture! This method also worked for snakes.

Sceloporus occidentalis, as the Western Fence Lizard is officially known, is a small lizard, less than 8 ½ “ long, with very rough scales on its upper surface. Their background color is light brown with blotches, bands, or ragged brown stripes. Turn the lizard over to see the amazing blue stripes on its belly and throat. Males have the deeper blue, females lighter and juveniles often none at all. During courtship and territorial disputes, the males do pushups to show off their colors. Presumably, deeper blues indicate a stronger, healthier and more virile male. Males fight to defend their territory but we never saw this behavior in our terrarium even though it was crowded with blue-bellies. Maybe this was because none of the males thought it was territory worth fighting for. Also, the terrarium lacked any suitable elevation where a male could do pushups to show off.

Fence LizardMating occurs March through June, depending on the altitude. Two to four weeks later the female digs a small pit in soft moist soil and lays a clutch of 3 – 17 eggs. She may lay several more clutches. The eggs will hatch in about 60 days, from July to September.

Fence lizards are common and frequently seen, as they are found in many habitats, from forests to grasslands to scrub. They love to bask in the sun in an elevated open place, such as a fence or a rocky outcrop or your woodpile. This makes them an easy target for hawks and snakes, sometimes shrews and kids with fishing poles. Speed and vigilance are their usual defenses, but they can sacrifice their tail if necessary. The tail will twitch after separation, distracting the predator. It takes energy to regrow a tail, so detaching one is not done lightly by the lizard.

Fence Lizard Dorsal ScalesLizards are cold-blooded, so they need to bask in the sun to warm up, and hide in cool places, crevices or under logs or brush, when too warm.

They eat bugs and spiders, ticks and scorpions. And they are very valuable in lowering the incidence of Lyme disease in areas where they are found. The bacterium which carries Lyme disease is carried by the western black-legged tick. Very young ticks frequently attach to fence lizards, especially around the mouth. A protein in the lizard’s blood (which the tick ingests) kills the bacterium, so the tick will be disease-free when it infects its next host. Treasure your blue-bellies!

Article by Eve Broughton. Eve lives in Whitethorn and was educated at UC Berkeley

 

Alligator Lizard

Posted in Amphibians and Reptiles, Fauna, Nature Articles, Uncategorized

emscincicaudask411The other morning, there were 2 alligator lizards basking in the sunlight on a window sill, and another hoping to get out the nearby door. The cat had brought them in. I decided to evict them. Two were sluggish or cooperative, but the other raced around and then hissed at me and bit me as I tried to pick him up. He held on like a pit bull. He had recently lost his tail and was probably not in a good mood. Should you wish to pick one up, grasp it behind the head.

Outside, I saw 5 or 6 within a 40’ stretch of garden. Obviously, previous years were great for alligator lizard survival and reproduction. Unlike many reptiles, alligator lizards are ovoviviparous: after mating, the eggs are retained in the female’s body. Usually there are 2 or 3 eggs. The fetuses get nourishment from the egg yolk. When they are developed, about 2 months after mating, the young “hatch” and are soon born. It will take about 3 years for females to reach sexual maturity.

The young are, about 3” long, thin and have smooth shiny unpatterned light brown skin; they look like small skinks. As adults, alligator lizards can be 10” long, with 6 of that being tail. Their heads are flat and triangular with pointed noses. Behind the eyes, their body slowly and slightly widen, without noticeable neck, until the middle of the abdomen, and then taper gently to the end of the tail. Legs are small and thin. There are 5 fine toes on each foot.young alligator lizard

In California, there are two species of alligator lizard. Both can be found in our area. The Northern species (Elgaria coerulea) can be distinguished from the Southern species (Elgaria multicarinata) by eye color and belly striping. Northern has dark eyes and a dark stripes running between the scales. Southern has light eyes and dark stripes on the middle of the scales.

Both are brownish, buff, or olive-brown on top, with darker crossbands. The scales are large, keeled, and slightly shingled. Separating the back from the belly, and running the length of the body from behind the corner of the mouth to the tail is a lateral fold of skin. The belly is usually light gray, and the scales are flat and shiny.

Alligator lizards occupy a variety of habitats, but they prefer moist areas and avoid deserts. Nor do they bask in sunlight in the open, as other lizards do. When they sun, there will be cover very close by. These pugnacious lizards are nice to have in the garden. They eat insects and grubs, snails, ticks, mites and spiders, and millipedes, and sometimes infant rodents.

Eve Broughton was educated at UC. Berkeley and lives in Whitethorn.

 

Garter Snake

Posted in Amphibians and Reptiles, Fauna, Nature Articles

Garter Snake 1In the late fall, as sunshine becomes rare and temperatures drop to freezing, garter snakes make their way to the hibernating den. Hundreds can gather in this hibernaculum, keeping each other warm. As garter snakes are slender and cold-blooded, they lose heat rapidly and this communal sleeping is necessary to conserve heat and fat stores.

Male and female snakes make sex-specific scents (pheromones) in their skin, allowing a snake to follow the trail of another snake. Some males make both scents, and this is an advantage, attracting both males and females to cluster around them in the hibernaculum. These “kleptotherms” also have an advantage in breeding. Maybe because they’re hotter.

Male snakes are smaller than females. In spring, when temperatures warm the hibernaculum, they wake and wander outside to feed and bask in the sunshine, returning at night to the group warmth. Soon, however, they stop feeding and allow their digestion to complete, as mating season is about to begin. When a female awakes and leaves the den, her pheromones attract many males, all trying to mate with her, swarming around her in a mating ball.

The female incubates the young in her lower abdomen for 2 to 3 months, and gives birth to 10 to 30 live young in the late summer. The young, 6 to 10 inches long, shed their skin and begin to hunt on their own, seeking earthworms, invertebrates, small fish and tadpoles . Living on a ridge, I see many small garter snakes at this time; the birthing chamber must be nearby. Sometimes, females mate again in the fall, and store the sperm until the spring to begin another fertilization and incubation.

Garter snakes are usually 2 to 3 feet long, brownish in overall color, with lengthwise stripes of several colors: red, yellow, white or beige. In between the stripes are rows of dark blotches. The snakes are active during the day, using their eyes to spot prey and their tongue to sense taste and smell. They can also sense ground vibrations.

Garter Snake 2We usually associate garter snakes with streams and their favorite food, frogs, but they are generalist carnivores, eating earthworms, fish, lizards, slugs, ants, and small rodents. Some species are immune to the toxin in newt skins and eat them too. The prey is swallowed alive.

Garter snakes have a mild neurotoxic venom, which is produced in small amounts, and delivered via some larger teeth in the rear of the mouth during the chewing – swallowing process. So unless the garter snake tries to swallow your finger, you have little chance of getting poisoned.

Predators of garter snakes include king snakes, kestrels and kites, harrier and hawks, mink and raccoon, opossum and skunk, and domestic cats. A garter snake will coil and strike to protect itself, although the usual reaction to a threat is to hide its head and shake its tail. It will also release a nasty-smelling juice from a cloacal gland.

Written by Eve Broughton. Eve lives in Whitethorn and was educated at UC Berkeley

 

Pacific Gopher Snake

Posted in Amphibians and Reptiles, Fauna, Nature Articles

Gopher Snake 1Pituophis catenifer

As youngsters, my brother and I had a terrarium built by an enterprising neighbor who had invented a fly trap which collected live flies. On a family camping trip to the High Sierras, we collected lots of fence lizards (and live flies to feed them), and then, the big prize, a juvenile gopher snake. The morning after we put the snake in the terrarium with the lizards, disaster struck. The snake, which probably thought it had been put in heaven, was caught swallowing a lizard. How could it do such a terrible thing?! I guess we forgot that snakes eat live prey. Snake was immediately banished from heaven.

At first glance, a gopher snake could be mistaken for a rattlesnake. Both snakes share a light brown background color with a series of darker brown to black blotches along the center. In the diamond-back rattlesnake, these blotches are surrounded by white stripes, creating the diamond pattern. There is no white on the gopher snake. Instead, below the center blotches on the sides are smaller dark spots in a variety of shapes. The rattlesnake’s tail pattern is a series of black and white stripes whereas the gopher snake’s is light brown with small dark spots.

The visual mimicry is also accompanied by behavioral mimicry. The rattlesnake has a large triangular head whereas the gopher snake’s head is more rectangular and thinner, although when threatened, it will flatten its head into a more triangular shape. It will also puff up its body, coil into the familiar rattlesnake strike pose, shake its tail (no rattles here, though) and hiss menacingly. If the gopher snake does strike, it will do so with a closed mouth. For all this threatening behavior, the gopher snake is not poisonous.

Gopher Snake 2Gopher snakes are fairly large: 2 ½ to 7 feet in length. Even hatchlings can be 20” long. In spring, males engage in ritual combat, wrapped around each other. The winner mates with the female. Sometime between June and late August the female will lay a clutch of 12 to 14 eggs. These incubate 8 to 10 weeks before hatching.

The Pacific Gopher Snake lives 12-15 years in the wild, feeding every ten days on small mammals, birds, eggs, lizards and frogs. (We should have known this before we put the snake in with the lizards!) They often hunt during the day, although they may be active at night during very hot weather.

Pacific gopher snakes range from Canada to Mexico, west of the Cascades and Sierras . They prefer drier open country (deserts, shrublands, grasslands and coniferous forests) to damp, dense forests, and range up to 9000’ in altitude.

Written by Eve Broughton. Eve lives in Whitethorn and was educated at UC Berkeley.

 

Water Penny Beetles

Posted in Fauna, Insects, Nature Articles

Psephenus_herricki,I_DSC48“Grandma, what’s this?” Danged if I knew. Bella and I were looking for aquatic insects in the Mattole, and she had captured something very weird in the clear magnifying box. We couldn’t find its photo in Audubon’s Field Guide to North American Insects and Spiders.

What she had captured was really strange: small, and copper-brown, it was shaped like a flat limpet and segmented like a chiton. By using a magnifying lens on top of the box’s magnification, we could see a mandible, legs and moving gills on its underside. I got the identification several days later from Pete Haggard, entomologist: Water Penny Beetle larva.

It was a fortuitous find. These larvae are only found in clean, well-oxygenated, unpolluted water. They prefer fast-moving water, clinging to the underside of rocks, and avoid habitats heavily covered with algae or inorganic sediments. They breath oxygen through their paired feathery gills, rely on claws on their legs for rock-clinging, and move away from light, preferring the undersides of the rocks . The larval water pennies scrape the thin layer of algae, microorganisms and feces from the surface of the rocks with their mandibles and eat this. The penny-like shape is created by flattened dorsal (back) plates which expand out to widen the sides. The one Bella found was slightly over ¼” long.

Water penny adult, photo by Joyce GrossThe larvae grow and molt several times during the summer, and then they create a small chamber in moist soil on land, where they, still in their larval skins, pupate and transform into the adult. The adults are small (less than ¼”), dark, with short fine antennae and a slightly flattened body. They breathe air and live on land close to the water. The adult water penny beetle survives for just a short time, 2 to 3 weeks, and may not even eat during this phase. Like many other insects with an aquatic phase, they exist to procreate.

Play behavior on wave-splashed rocks has been observed before mating. Fertilization is internal (inside the female’s body). The female lays small, bright yellow eggs, hundreds of them, on the edge of the stream, or submerged objects in stream riffles. The newly hatched larvae crawl into the water to repeat the cycle. Next summer, we might find another one.

 

Written by Eve Braughton. Eve lives in Whitethorn and was educated at UC Berkeley

 

Gophers: Good Guys?

Posted in Fauna, Mammals, Nature Articles

GopherNot if you are a farmer who has seen his potato plants being mysteriously pulled underground. Not if you see mounds of fresh dirt appearing on your golf greens. So how could gophers be good guys?

Gophers dig extensive networks of tunnels underground and bring that soil up to the surface as mounds. This moves new minerals, organic compounds and moister soil to the surface and aerates the soil. This enhanced soil quality and moisture enables a larger diversity of plants to grow. So gophers are appreciated in the wild.

But in the vegetable garden, they are a menace. They feed mostly underground, dining on roots, stems, bulbs, and leaves, often pulling the whole plant down into the tunnel. At night they may come out to forage on foliage near their burrow entrances. They have fur-lined check pouches which they can fill with food to carry to their storage chambers, or fill with soil to bring to the surface. The food put in the storage chambers is eaten in times of low food supply.

Like all rodents, gophers have very large, ever-growing incisors. They use these for gnawing and for digging, which they can do without ingesting large amounts of dirt by closing their cheeks behind the incisors. They also use their front claws to dig tunnels, which can be more than 450’ long. The burrow system is complicated, with a main burrow often 90’ long, with 3 to 4 forks. Off the main gallery, they have side chambers used for storage or for nesting. All that digging uses huge amounts of energy, which the gopher gets from eating huge amounts of food. Both sexes build nests of dry, shredded vegetation formed into a hollow ball. Usually, each animal lives in its own burrow system.

Physically, gophers are well adapted to the fossorial life, with a stubby body and short sturdy legs, short hair, and small eyes and ears. Their eyes are receptive to ultraviolet light as well as to two visible (to us) colors (blue-green and green). Males are larger than females (7” to 11” vs 6” to 9.5”) because females stop growing after their first pregnancy and males grow throughout their lives.

On average, a mature female can produce 2 litters a year, with 5 young in each. The young are born pale, blind, hairless, and with poorly developed ears, although the cheek pouches are fully-formed.

The pocket gopher found in California is Thomomys bottae. It is also found in Nevada, southern Utah, Arizona, western Texas and northwestern Mexico. They occupy a wide range of habitats, from montane meadows to dry deserts, in soils ranging from thick clays to loose sands and silts.

Good guy or bad guy? It depends on where they are.

 

By Eve Broughton. Eve lives in Whitethorn and was educated at UC Berkeley.

 

Neotropical Migrant Songbirds: A Miraculous Journey

Posted in Birds, Fauna, Nature Articles

Written by Kyle Keegan

 

                                                                                                                                                                                  As the days become longer and the storms of winter pass, each year brings the promise of an ancient ritual that has taken place on the North Coast for millennia—Spring migration. Oak woodlands, forests, and meadows that were virtually silent during winter months become saturated with the songs and antics of some of our most colorful and vibrant bird species: Western Tanagers, Black Headed Grosbeaks, Lazuli Buntings,Vireos, Warblers, Hummingbirds and Swallows. Some of these birds who just weeks before may have been foraging in jungle canopies along side Howler Monkeys and Toucans, now find themselves in a temperate world—among Gray Squirrels and Steller’s Jays.

Why Leave the Tropics?

Why do these small birds leave the tropics in the first place, risking their lives on this long journey? Scientists theorize that the greatest draw to neotropical migrants is the brief, yet spectacular abundance of insect activity during our spring and summer months. During this short period, the explosion of insect life provided by temperate ecosystems is virtually unparalleled, allowing migrant birds to coexist with our local resident species, while capitalizing on the highly nutritious food. Research also suggests that breeding success may be higher here than in the tropics where parasites and predators are more prevalent.

A Dangerous Journey

Migration is inherently dangerous. Neotropical migrants must travel over mountains, deserts, forests, vast expanses of monoculture, and urban sprawl during their northbound journey; with many species flying by night. Some birds such as the Cliff Swallow (Petrochelidon pyrrhonota) come from as far south as the Amazon Basin in Brazil, while most other migratory species winter in Mexico and Central America. During this journey they use a complex array of strategies to orient and navigate themselves. Over their lifetime neotropical migrants learn the “sky map,” using the stars and sun as a travel guide. They also utilize the topography (landmarks) and wind directions, as well as subtle cues from the magnetic field of the Earth. The course they take is a learned one, shaped over evolutionary time and passed on by their elders.

During the extended journey they may be threatened by: storms, pesticides, house cats, collisions with windows, wind turbines and high-rise buildings, and increasingly—the erratic weather caused by climate change. A freak frost or prolonged cold, wet weather can cause large numbers of migrants to perish.

Despite the risks, great numbers of them arrive each spring to serenade us amidst blooming wildflowers and lush green landscapes; quickly getting to work establishing territories, finding mates, and building nests.

Linking Landscapes and Culture

Neotropical migrant songbirds comprise over half of the species that we hear singing during the spring and summer months on the North Coast. The presence of neotropical migrants serves as both an indicator of the health of our North Coast ecosystems, as well as the health and integrity of their tropical winter lands—linking the landscapes of Humboldt to the far off territories of Latin America. A unique example of cultural and ecological interconnectedness.

 

Photo of a female Western Tanager by Marie Raphael

 

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