Sunday, May 3, 2015

Floral Visitors 10

The new growth season and lengthening days brings much in the way of work and although the days are longer time seems to dwindle. I will be reducing the number of posts here as there is just not enough time to "do it all"! But that doesn't mean I am going to stop, so check up from time to time or subscribe to receive new posts in your email when I publish them (you wont get anything else, only the new posts). You can subscribe to receive updates in the widget to the right, though it doesn't appear on devices unless you are viewing this page in "desktop view" (that's how it is on my Windows phone anyway). Enjoy!

Plectritis macrocera
There is a large patch of this small native annual, which I have identified based on the leaf size, placement, and flower parts. This species is typically white, and identification guides rarely mention the pinkish form. This patch caught my eye last year when it was literally humming with foraging honeybees. This year I have had limited free time to observe it, but solitary bees, various flies, and a butterfly or two have shown great interest. The area is also dense with Calochortus tolmiei (see below), but many of those seem to be non-flowering plants at this time.

Iris chrysophylla with mating sweat bees
The native irises are very floriferous this year,  with many flowers covering every clump. Last year I only witnessed a few pollinator interactions, I photographed a few solitary bees foraging for nectar. They entered the flower and undoubtedly functionally pollinated the flowers instead of stealing the nectar. This year, I have not had the opportunity to see this (though I'm sure it is happening), but I did catch these bees on film. When I took the photo I thought it was a single strange looking bee. Upon blowing it up on the computer I discovered it was two, the female's face covered in pollen with the slightly smaller male on her back. 

They are still mobile, as they flew away after taking a few photos (I got too close). Despite having an awkward disposition, they still forage and fly from flower to flower. This is distinct between solitary bees and honeybees, the queens of the latter go on mating flights high in the air and do not partake in floral visitation at that time.

Iris chrysophylla with beetles
It was hard to find an iris without these small flower beetles. My best guess would be that they congregate at flowers to find mates and hook up. I doubt their role as "pollinators", none had a trace of pollen and in this photo it is clear that the beetles on the lower left are eating the flower itself. This doesn't mean that they wouldn't pollinate the flower, I would just be skeptical about that part. Ants were also common on a few clumps, though I couldn't tell if they were after the nectar or if other herbivorous insects had left behind some honeydew (the name says it all, honey-DOO).

Lamium maculatum with bumblebee
Into the garden, the dead nettle (Lamium maculatum) is flowering well and has attracted some bumblebees. Nearby are some shady garden beds and my small forest garden. Planted under shade are Pulmonaria's, Polemonium caeruleumSymphytum officinale, Hyacinthoides, and an ever-growing variety of others. The ones mentioned were also visited by bumblebees in the past few weeks though despite my best effort I was unable to get it on camera!

Fragaria vesca with dagger fly
Woodland strawberry is very floriferous this year, the most flowers I have ever seen of it here! It produces tiny super sweet and flavorful pseudofruits the size of the tip of my pinkie. Bees of any sort show no interest in these, while a variety of flies are common on them, such as dagger flies. This fly here can be seen drinking nectar.

Fragaria vesca with beetle
The same beetles seen on the irises (and the Narcissus in years past, btw), are occasionally found on the strawberry flowers. I do wonder if pollen is a part of these beetles diets or if they are only on the flowers as hang-out spots, trying to pick up chicks. Just a shot in the dark, if anyone can ID this beetle, I'm open to suggestions!

Alyssum montanum with flies
When the Alyssum began to flower, I doubted anything would be attracted to it. How wrong was I? Very, very wrong. All kinds of flies, wasps, bees and even butterflies are attracted to this fairly compact form ('Mountain Gold') for the nectar. Here a dagger fly and a house fly feast, completely oblivious to each other.

Alyssum montanum with honeybee
This honeybee moved quickly from flower to flower, the nectar apparently readily accessible.

Allium trifoliatum 'Cameleon', April 19th
This beautiful form of Allium trifoliatum is in flower now. It grows to maybe ten inches. The flowers open white and age to pink. The selection has a few names, it is sold as 'Eos', 'Cameleon', and 'Chameleon' depending on the vendor. It was selected by Wim de Goede, who apparently had no idea what the species was when he named it. So far, it has been of interest to beeflies, who look like bees with their hairy bodies but have a very long needle-like proboscis and hover over the flowers when they feed.

Allium trifoliatum 'Cameleon', May 1st
The same plant as above a week later, the older florets already changing color. I am hoping this plant sets seed. Allium's are easy to grow from seed, and easy adaptive plants in the garden. Seed sown on the surface of the potting medium in the late Autumn or winter will often have good germination.

Potentilla arguta with ants
Cinquefoil is sparse in the field behind our house. At first glance it resembles the buttercups (Ranunculus) which have since mostly finished blooming. Due to their very low flower density (not many plants growing closely together, less flowers in a given area) I would not expect many floral visitors. However I was surprised to discover these ants. Interestingly I didn't even see them until  blew up the photo on the computer. Their bodies are covered in pollen, I always wonder if they are really functional pollinators of many plants.

To properly test their effectiveness as pollinators many tests would need to take place. Many plants would be required. Say 100 flowers, divided into groups. The first group would be bagged before opening to exclude pollinators altogether. The second group would be emasculated (remove the anthers before the pollen dehisces to rule out self-pollination and is bagged to exclude pollinators. The third group would be allowed to be visited by ants, but other pollinators excluded (a fine mesh open enough to allow ants, small enough to keep others out). The fourth group would be hand pollinated, bagged to exclude all pollinators. The fifth and final group would be left to be open pollinated. After the bloom is over, testing which plants produced seed (and if the seed is viable) would conclude whether ants are effective pollinators of the given plant (this test works with most flowers, except with the emasculation which could be difficult with small flowers).

If group one produced seed, there is the possibility that the plants can self pollinate with their own pollen. If group two produces seed, apomixis may be taking place. If the first two groups do not produce viable seed, and group three does, ants may in fact be considered as effective pollinators of the given plant. The fourth and fifth groups could be control groups (hand pollination in group four would assure pollination did in fact take place in case the true pollinators of the plant were scarce or the weather was unfit for pollination to take place naturally).

Eschscholzia californica with beetles
California poppies here are visited by a variety of small solitary bees, syrphid flies, and tiny beetles. My beehives are situated by a field of these wildflowers, yet I have yet to witness a single honeybee show interest in the flowers. I have also planted some of these closer to our house. The wild field types have shown a wide variability in flower shape and color, and are very compact plants. The seed I have purchased and planted grew into large plants with uniform flowers in color and shape. The field types are visited by a wide variety of small bees and beetles, while the types I had planted have mostly been attractive to syrphid flies.

Poterium sanguisorba
These strange inflorescence's with much divided leaves cover a bank on our road. My attempts to identify them have failed. Any hints? Either way, I have seen bumblebees visit the flowers recently. The way the anthers hang down leads me to think they could be a wind pollinated species, or somewhat intermediate between wind and insect pollination similar to Plantago.

Update: This plant was recently identified as a species of Poterium by the nice folks of the Native Plant Society of Oregon. Thank you all!

Marah oreganus with tiny beetle
Marah, or sometimes called manroot, is a genus of cucumber relatives that grow from large underground tubers. They produce spiny melon-like fruits, not particularly edible. They grow on roadsides and ditches, often on dry banks. The vines sprawl along the ground or sometimes up fences or other plants with tendrils. The flowers are born on terminal inflorescence's situated vertically, opening from bottom to top.

Marah oreganus with a tachinid fly
A single plant can spread to form a wide patch, becoming attractive to many small insects when in bloom. Tiny beetles and this strange tachinid fly were on some of the flowers, while a tiny bee that I was unable to get into focus was also interested in this plant for nectar.

Cystus scoparius with honeybee
Honeybees and a variety of others are attracted to the attractive blooms of Cystus. The twiggy shrubs are covered with the pea-like yellow (sometimes red blotched) flowers while in bloom, sometimes turning hillsides yellow. The plants were originally brought by European settlers, and had quickly escaped cultivation (they are highly invasive). The plants were used to control erosion.

Cystus scoparius, an aggressively invasive shrub in Oregon
Sometimes called broom, Cystus is a noxious weed in Oregon. It is not greatly inhibited by herbicides, deep root systems make pulling ineffective, and it regrows after fire. The seeds are formed in pods similar to Vicia and Latyrus, and consistent with others in the Fabaceae (pea family). The pods split down the center and curl up like a spring, springing the seeds large distances from the parent plant. This is their main method of spread.

Cercis sp. (Redbud) with mating bumblebees
The redbuds have been in bloom for a while now. Many types of pollinators visit the small pea-like flowers. I was surprised to see these two bumblebees, currently in the act of mating, moving from flower to flower! This was the best photo I could get, though their silhouette is still visible to the right of the center. Many other bees, including honeybees, and flies and beetles, were visiting the flowers.

Cornus sp. (Dogwood) with mating beetles
The dogwoods have just begun to bloom. Despite the colorful bracts (pink in this photo), the true flowers are clustered together inside. They have not opened in this photo. As mentioned before, beetles sometimes meet in flowers to mate. Bowl-shaped flowers are particularly of interest to beetles, offering a somewhat sheltered place to meet, as well as possibly serving as a source of food.

Prunus virginiana with beetles and a spider
Chokecherry, so called from the bitter taste of the fruit, is a small suckering shrub or tree. It is covered with drooping racemes. Tiny beetles, like the one to the left of the center, were all over this one. Small bees were also present, though not in large numbers. Tiny flies and gnats also showed interest, but also appear to be feeding another visitor of sorts. See the spider?

Prunus virginiana with mating beetles
It seems to be that time of year, these beetles were mating. Once again, I didn't even notice until I blew up the photo on the computer.

Madrone, or sometimes madrona, is a large tree in the Ericaceae. The trees have bark that peels away, revealing a smooth reddish bark underneath. The flowers are borne in clustered inflorescence's. The trees in my area haven't flowered well this year, and in fact have not flowered at all in two years. Two years ago a single tree (over 200' tall) was covered in flowers and a perfumed scent filled the air from the nectar. The sound of the pollinators could be heard from a distance, it was an audible hum which included a thousand bees (if not more) and many hummingbirds. This year, flowers are sparse. I believe that the trees in this area are suffering from a disease or fungal infection, evident by the black spots on the leaves. Time will tell if they can recover.

Arbutus menziesii with reddish bee or wasp
Many of the floral visitors to these flowers this year are bees (or wasps), particularly these small reddish types. Other bees are either Eucera or Megachile, though my bee identification skills are guesses at best. In previous posts I had identified a large grey bee as Megachile, though I now believe it to be Eucera. I'm sure it is not crucial information for most of you, but I would not want to be guilty of spreading false information.

Arbutus menziesii with solitary bee robbing nectar
For a long time I have noticed small holes on the sides of the flowers of madrone (and Arctostaphylos, btw). This is a sign that something is robbing the nectar and not serving as a true pollinator, bypassing the reproductive organs to get at the nectar. This solitary bee in this photo is doing just that, biting a hole in the side to steal the nectar.

Prunus sp. with beetle
In the parking lot of my work is this small shrub, my best guess is a member of the genus Prunus. The plant is covered in flowers, and highly attractive to bumblebees and solitary bees as well as flies and beetles.

The Calochortus has been very floriferous this year, and has been highly attractive to pollinators. Solitary bees, flies, beetles, ants, moths, and butterflies have all flocked to the abundant bloom. Here is a montage of some of the interactions I was able to capture on film.

Calochortus tolmiei with sweat bee
Bees are mostly attracted to the nectar, secreted at the base of the petals where there is often a blotch of color, purple in the case of this species. Some bees circle around the bottom of the flower, collecting nectar as they go. I will conclude with a few more photos, no descriptions required:

Calochortus tolmiei with dagger fly

Calochortus tolmiei with small solitary bee

Mating sweat bees


  1. Plectritis macrocera is a lovely photo, can we buy it as a desktop backdrop. It's interesting that here with ants, bees, snails... some flowers remain unpollinated. Native pollinators the wrong dimensions or not interested; but the same flowers are easily pollinated by hand. Any flowers whose only known pollinator is man?
    As to blowing up photos with your computer, do be careful old chap.

  2. a small spelling correction for Calochortus tolmiei, your second to last "i" is missing.

  3. I love the wealth of observations you have posted here!

    Those "beetles" on the Cornus ... I believe they are Hemiptera.

    1. Thanks, I've since identified them as Leptocoris rubrolineatus, Western boxrlder bug. Many of my older posts were lacking proper ID's or at worst the wrong ID.


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