Shooting stars and busy buzzing bees

On the narrow strip of grass between the trees and the stones of the river bank, where the sun shines, but out of reach of the tide that comes up and salts the ground, bright pink specks were dancing in the wind. I had to scramble down to see what they were.

And now, I've fallen down another rabbit hole.

The flowers were shooting stars.

Shooting stars, Dodecatheon sp.

Another plant. You can see where they get their name.

Because I like those shrivelled petals and the growing seed capsules.

And now, the rabbit hole. Reading the notes on a different shooting star, in the guide book, I found this:

Shooting stars provide a good example of "buzz pollination". The anthers shed pollen into the stamen tube, from which the pollen can be dislodged by sound waves set up by the buzzing of bumblebees. (PoCBC, 1994)

Actually, this is wrong, in several ways. But it sent me to Google to find "buzz pollination".

First, now it has been established that what dislodges the pollen is the vibration of the bee's wing muscles. The sound has a minimal effect.

And how this works: the anthers, the pollen-producing (male) part of the flower, usually spread their pollen easily, by wind or water or gravity or just contact with a pollinating insect. But in some plants, like these shooting stars, or tomatoes, or rhododendrons, for example, the pollen is locked inside.

In most cases, rigid tubular structures are formed by modified anthers or groups of anthers, which only release pollen via small apertures that range from tear-shaped slits to apical pores <100 μm in diameter. (National Library of Medicine) {Microns are a length of measurement equal to one millionth of a meter. (100 µm is equal to 0.1mm.)}

Because of this shape, they are often referred to as poricidal anthers. These poricidal anthers are only able to release pollen when vibrated at a specific frequency. (Wikipedia)

A researcher at the Arnold Arboretum (Harvard), Callin Switzer, took recordings of bumblebees gathering pollen. He found "an average buzz pollination frequency of about 270 Hz. The pitch of this vibration frequency is equivalent to a C-sharp above middle C on the piano." 

The "buzz" is produced by the same muscles that power the bee's wings, but here, the wings are held still, and the body vibrates, shaking loose the pollen, which the bee then carries to the next flower. (Keeping some for herself, of course.)

In addition, flower handling, including applying a tight grip to the base of the anthers, and the curling of the bee’s body around the flower may also help in the mechanical transmission of vibrations to the flower. (NLM)

So now I have to go back and look at all my bee-chasing photos to see those curled bodies. 

Thinking about this, I remembered that I had some old (2007) photos of those enclosed anthers in rhododendrons:

Anthers and stigma.

Zooming in on the anthers. Each one has two tiny holes. The pollen inside is attached with a sticky substance, which sometimes glues the bees to the flower.

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En un estrecho tramo de tierra entre el bosque y el rio, donde el sol alumbra las hierbas, y fuera del alcance de las mareas que llenan de sal el suelo, el viento hacía bailar manchitas de color rosa fuerte. Tuve que hacerme camino para ir a ver que eran.

Y por ello, fui en pos del conejo blanco de Alicia. (La del País de las Maravillas)

Las manchitas eran flores. Dodecatheon sp., conocidas como Estrella Fugaz.

Fotos #1 a 3: Las flores. Por su forma, se ve donde sacan el nombre; parecen estrellas que caen como flechas. Y me gustaron los pétalos marchitos, y las cápsulas donde se están formando las semillas.

Y ahora, la distracción. Estaba leyendo las notas en mi libro guía (Plants of Coastal BC, 1994) referentes a otra flor del mismo género, y vi esto:

Las flores Estrella Fugaz proveen un buen ejemplo de la "polinización por zumbido". Las anteras introducen su polen en el tubo del estambre, de donde se puede despegar el polen por medio de las ondas de sonido causadas por el zumbido de los abejorros. (PoCBC, 1994)

Bueno, en varias maneras, se habían equivocado. Pero sirvió para enviarme a Google, buscando "polinizacion por zumbido".

En primer lugar, ya se ha establecido que lo que libera el polen es la vibración de los músculos de las alas del abejorro. La producida por el sonido tiene muy poco efecto.

Y como funciona esto: las anteras, que son las partes masculinas de la flor y que producen el polen, en muchas plantas esparcen facilmente su polen, sea por el viento, la lluvia, la gravedad, o el contacto con insectos polinizadores. Pero en algunas plantas, como por ejemplo en estas estrellas fugaces, en los tomates y papas, en los rododendros, el polen se queda encerrado.

En la mayoría de los casos, estructuras tubulares rígidas son formadas, constituyéndose de anteras modificadas o de grupos de anteras, las cuales solamente emiten el polen mediante aperturas pequeñas que van desde rendijas en forma de gota hasta poros apicales <100 µm de diámetro. (National Library of Medicine) {El micrómetro o micrón, µm, es una unidad de longitud equivalente a una milésima parte de un milímetro.}

Por esta forma, comunmente se llaman anteras poricidas. Estas anteras poricidas solo pueden liberar el polen cuando vibran a una cierta intensidad. (Wikipedia (en))

Para aflojar el polen, la abeja se aferra a la flor y mueve rápidamente sus músculos alares, sin mover las alas. Esto produce un zumbido con un sonido característico; esta vibración afloja los granos de polen y hace que emerjan de la antera. (Wikipedia)

Un investigador con el Arboretum Arnold (Harvard), Callin Witzer, hizo videos de abejas mientras juntaban el polen. Halló "una frecuencia promedio de las vibraciónes alrededor de 275 Hz. Esta frecuencia es equivalente a la nota Do sostenido un octavo adelante del Do mediano en el piano."

Además, la manera de manipular la flor, incluyendo aplicar un control firme en la base de las anteras, y encorvando el cuerpo de la abeja alrededor de la flor, pueden ayudar con la transmisión mecánica de las vibraciones a la flor. (NLM)

Ahora tengo que mirar otra vez todas mis fotos de abejas para ver si puedo observar esa postura.

Pensando en todo esto, me acordé que tenía unas viejas (2007) fotos de las anteras encerradas de los rodendros en mi jardín de entonces.

Fotos; el centro de una flor de rododendro, y luego, viendo las anteras más de cerca. Cada antera tiene dos poros. En estas flores, el polen se detiene en su lugar con una sustancia pegajosa, con la cual, a veces, las abejas se encuentran atrapadas.

Keeping her distance

There was a hummingbird on the tip of a branch of a pear tree, just close enough to see her shape. The camera would do better, but by the time I'd taken off the lens cap, she had gone next door, to perch on the tip of a branch of a walnut tree. Against the light, and almost at the limit of my camera's lens. Playing hard to get.

I waited. For an hour and a half I sat there, camera in hand. And all that time, she either flew about, or (mostly) perched on that distant branch.

New walnut leaves and the hummer next door.

Tight crop. At least she stood still!

A robin was more cooperative:

Why do robins always look so worried?

"Cheer up!" he says.

And there were rhododendrons across the lawn.

Pink rhodos.

An hour and a half well spent.

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Un colibrí hembra me esperaba en la punta de una rama del peral. Apenas suficientemente cerca para que mis ojos viejos pudieran distiguir su forma. La cámara ve mejor, pero para cuando había retirado la tapa del objectivo, la pajarita se había ido al jardín del vecino, donde escogió una punta de las ramas del nogal, contra la luz, y casi al límite del alcance de mi lente.

Me quedé esperando. Por una hora y media me quedé sentada con la cámara en mano. Y en todo ese tiempo, ella o se iba a dar una vuelta corta, o la mayoría del tiempo, se posaba en esa rama distante.

1. Hojas nuevas del nogal, y la colibrí.
2. Foto recortada. Por lo menos, cuando posaba, se quedaba quieta.
3. Un petirrojo fue más dispuesto a cooperar.
4. ¿Porqué será que los petirrojos siempre parecen estar preocupados?
5. Y había flores. Estos son rododendros color de rosa.

Total; fue una hora y media bien aprovechada.

Colours of spring

Rhododendrons

With one wee weevil.

Bee's-eye view.

And an iris.

Purple and yellow. No weevils visible.

Because I was browsing in a roadside garden, and its flower season.

Small wonders

April, between showers . . .

Red-stemmed moss.

Plume moth, sleeping on the wall by the door

Robin, pulmonaria, and daffs. And a few leaves of lettuce, still surviving cuddled up to the pulmonaria for protection from the slugs.

The young raccoon, back again for a drink, keeping his eye on me.

He needs a nail clipper; look at that thumb nail!

Raccoon fingernails. I'm not volunteering to trim them for him.

And the first rhododendrons we've seen this year.

And the cup mushrooms are out in force! But each time we've seen them, so far, it has been pouring rain.

On deadheading rhododendrons

A few observations:

• While it is theoretically possible to completely deadhead a rhododendron, it has never been done. There's always another head hidden away in plain sight.


• I am convinced that while I'm on one side of the rhodo, new flower heads on the other side are speed-budding, -blooming, and -dying.


• Want to hear a rhododendron snigger? Say, in its hearing, "I guess I'm done; I'll call it a day." Then turn around real quick and look at the area you just finished. See the new/old head? Right in front of your nose?


• The point of a rhododendron leaf, when poked into an eye, really hurts.

Just saying. Back to work!

Of bugs, flowers, and muddy lenses

I came home from hours of driving in the hot sun, in the front door and straight out the back to the shady garden. So cool! So green! So easy on the eyes! So buggy! I went back in for the camera and macro lens.

Fly on London Pride flowers

Delicate bloom of London Pride. Taken with macro lens.

American House spider. One of Fat Momma's great-greats.

While I was up on a ladder taking this photo, I dropped the camera. It was on a cord around my neck, so no harm done, but the macro lens fell off, landed in the damp mud of the garden, and split in half. This isn't as bad as it sounds; it's a home-made stack, which cost me nothing but work. I can fix it, given a slow, rainy day.

But I needed it for bugs. Or maybe not; I went in and brought out my old Olympus (SP55OUZ), which I had almost stopped using, because it got dust inside the lens. (At London Drugs, where I bought it, they told me the repair would cost more than the camera.) Sometimes, especially if I use the flash, the spots show up on the photo. But it takes good macro photos, as long as I remove the spots later.

I decided to experiment; take the same photo with the little Sony (Cybershot) and with the Olympus, then compare them.

Petunia. With the Sony. The Olympus needs more light.

Dutchman's Breeches. With the Sony.

Harvestman on hydrangea leaf. Sony

Harvestman under hydrangea leaf. With the Olympus. Almost enough light.

Tiny Cross spider. With the Olympus and flash. I couldn't get close enough to focus with the Sony without scaring the spider away.

Rhododendron buds. Sony. The Olympus doesn't like extreme lighting.

Ant in center of rhododendron. Sony. Not enough light for the Olympus. It doesn't allow flash with Super-Macro.

Bee on rhodo bud. Note the yellow pollen sac on his leg. Sony. The Olympus was 'way too slow.

Rhododendrons in the shade with sunlit trees behind. Almost looks artificial. Sony, again.

The upshot of all this is that I am still happy with the little Sony; it's fast, it's light, and it handles contrasts well. I can take photos one-handed, which helps when I'm up ladders. On the downside, it doesn't focus if the surroundings are too busy, and the flash is unpredictable. When it all works, it's great. But I need to keep using the Olympus; given enough light and time, it does much better on tiny bugs, as long as they're sitting still.

And maybe, when I rebuild the macro lens, I can adjust it more carefully to the Sony. I think I'll put it on a strap, too.

A visit to Oyster Bay Plant Works

... still catching up on our vacation photos ...

On an after-supper walk near our motel in Campbell River, we discovered a gate with a sign; Oyster Bay Plant Works - Open 9 AM. Through the bars, it looked green and inviting. We hurried over right after breakfast the next morning.

Laurie surrounded by beauty.

The gate opened on a wide, bricked path with gardens on both sides; there seemed to be no-one about. Laurie disappeared down a mowed trail to our right, and I dawdled, taking photos of an old Austin in a garden shed. (I love old cars.) Before I was done, the gardener, Linda, had appeared, gloved hands still holding her tools. She was very friendly, and invited me to wander freely around; she would be handy if we needed her. I thanked her and followed Laurie into the shrubbery.

This quadrant is planted mainly in a variety of rhododendrons and azaleas. Flowering season for these was past, but other plants took up the slack. And the green was soothing after the harsh sunlight of the highway. The paths meander, always hiding what lies ahead, but tantalizing us with glimpses of colour.

Astrantia

Native rose, above my head.

Magnolia variety. When the light hits it just right, it looks really blue. The underside of the leaves wears a cinnamon fuzz.

At intervals, carvings and sculpture add interest.

Allium. Notice the bulblets at the base of the flowers.

In spite of the shade, the day was heating up already. I was glad when we came upon a small pond, with a bench under overhanging branches. I sat and rested, lazily taking photos from the bench. Laurie, more resistant to heat than I, scrambled around, getting the perfect angle.

The pool, from my shelter.

Small blue flower.

Tall pink flower, three-petalled.

Stone turtle, on moss and ground cover.

Back on the main path, we met Linda again. I asked about growing conditions for a pitcher plant that I had discovered by the pool. (More on that in a later post.) She took us under her wing, and gave us a tour of the rest, including the view from the front porch of her house. (Gorgeous!)

Then we went to look for plants for my deep shade garden at home.

The hosta garden. Deep shade. Garden sheds and office in back.

I wanted an epimedium; they retain their beautiful warm colour right through the winter, snow and all. And a hellebore for their early spring flowers. Linda found me both of these, and added a bonus; a small pitcher plant. I also wanted a Spring Snowflake, but try as I might, I couldn't remember the name, nor describe it accurately. Leucojum vernum. Now I've got it memorized, too late.

White lilies, like a flock of butterflies among the rhodos and ferns.

Laurie caught up to me, and we said our goodbyes. At the little office, while Linda toted up my bill, I noticed this tiny delight:

Red and cream. Unidentified.

I had a hard time choosing photos; there were too many. Another dozen are in the Flickr Oyster Bay Garden Works set.

And Linda, if you're reading this, the plants made it home, two hot days trip in the car, in perfect condition. I kept them inside the car, with the air conditioning on, and shaded. When we parked, I draped a wet towel over them to keep them cool. They're doing fine in the shade of my garden. Thank you!

.

Update on rhododendron pollination

In my musings on rhododendron anatomy, yesterday, a few questions about their pollination presented themselves.

Today, I fired up "the Google".

First, why didn't I see pollen on the anthers?

From a discussion of hand-pollination of rhododendrons, I learn the following:

"The stamen consists of the anther, which has two chambers, each with a hole through which the pollen is dispensed. The chambers are called lobes or pollen sacs and contain masses of pollen grains."

Here's that photo, again:
So the pollen is inside those little purple tubes. But there's more:

"Pollen is not a dust as in many plants, but rather long, irregular (tacky) stringy masses. The pollen ripens before the flower opens. After the flower opens, the pollen may soon be lost."

The flowers that I examined had been open for several days. The pollen was long gone. In an anther containing pollen, I should be able to see those stringy masses protruding from the holes. If not, I may be able to shake the pollen out, which is what the bee would do.

The second question was whether the pollen would come from the same flower, or from another.

The stigma (the female receptor, that red tip above) is ready for pollen about three days after the flower has opened. In other words, it will be receiving pollen from another flower, freshly opened. (Pollen can be dried and frozen for later use, but the rhodos aren't up to those tricks. Only human hybridizers do that.)

Rhododendrons and their relatives, the azaleas, hybridize quite easily, as we can see quite easily here in the Vancouver area; there are as many varieties of rhodies as there are backyards, I think.

And I found this fascinating:

"Once the stigma ripens, a critical process must take place whereby the stigma excretes a thin syrup and furnishes nourishment to the pollen which then forms a sprout-like process called a pollen tube. The style (stem) portion of the pistil has a channel running down its center from the stigma to the ovary configured with loosely formed cells through which materials easily pass. The pollen tube grows, heading down this canal. The pollen tube develops into a long slender thread-like structure as it grows down the style canal toward the ovary. At its lower end, the pollen tube contains the male cells and vegetative nucleus. In the ovary, the female (egg) cells are present. After a minimum of 24 hours at approximately 68°F, the pollen tube enters the ovule; the male nucleus is discharge and fuses with the egg nucleus to form a new seed. A separate ovule and a separate pollen cell are required to produce each seed. Dr. Bowers further writes that "up to several hundred pollen tubes may pass down the style at any one time and these may not be of the same variety or species. " Therefore, it is entirely possible in open pollinated flowers for one rhododendron flower to be successfully pollinated by several different sources of pollen at once."

And after all that effort, I come along and deadhead every single stem.