Saturday, April 18, 2015

Floral Visitors 9

This week has been marked by excellent sunny weather, not too hot, not too cold. Many bees and other pollinators have been out, including many that I had not had the opportunity to photograph. These include bumblebees visiting the flowers of the multiple Pulmonaria's and Polemonium caeruleum, with a wide variety of bees visiting Symphytum, Brassica rapa var. perviridis, Acer's, Plectritis, and more. Still, I consider myself lucky to have photographed (or in one case, filmed) the following observations. 

Photographing pollinators is sometimes a game of patience, or sometimes just plain luck. One must be still and calm, slow to avoid scaring off the subject! Many bees and other pollinators are very skittish and will flee when you approach, to them a large mass moving towards them is often not a good thing. Sometimes sitting and waiting is the only way to see what types of insects visit the flowers of a given plant, though there is always the chance to see nothing. Sometimes just being there may keep some bees away, I've noticed on a few occasions that my very presence will cause a particular branch of a flowering fruit tree (the one I'm nearest) to be completely devoid of pollinators.

Calochortus tolmei with a black bee
I was lucky to spot this bee in the newly opening flowers of Tolmei's star-tulip (Calochortus tolmei). However, the bee does not appear to be there to forage, because the pollen has not yet dehisced from the anthers. Compare the anthers of the flower above to the one below, note the blue-grey pollen on the picture below. This bee, also one I had seen in the flowers of Narcissus, had appeared to be in the flower for shelter, maybe overnight because the flowers close at night.

Calochortus tolmei
I have observed bees of different types visit the flowers in the past, but visits seem to be relatively few. This may be because the plants do not seem to reproduce asexually (bulb divisions) very often if at all. While many will sometimes grow near each other, they often only have a few flowering individuals. This low flower density may explaine the low visitation rates that I have observed. I know this is a widespread species, extending south into California, I am curious to know if there are clumping forms in different regions or if this growth habit is typical for the species?

Lomatium utriculatum with a small bee and beetle (see video below)
Just after I photographed the Calochortus pictures, I turned around to see this small bee and beetle on this small Lomatium. This is the first time I had seen a bee on any Lomatium, previous observations were of flies and a few moths (below). Keep in mind the inflorescence is about 1.5" and maybe 5" off the ground. I recorded this observation here:

Lomatium utriculatum with a tiny moth with long antennae
Many of these small moths with disproportionately large antennae were visiting the flowers of Lomatium utriculatum. I had to creep in with the camera slowly, as they were very weary of my presence. The full sun made the flowers overexpose a bit, a good reason to avoid full sun macro photography.

Veronica umbrosa 'Georgia Blue' with a syrphid fly
Though I have occasionally witnessed bumblebees on this Veronica, the majority of the visitors are flies, particularly syrphids. They are mainly interested in the highly accessible nectar, the anthers yielding little pollen. Hoverflies large and small visit these flowers, which cover the entire plant. This plant shares the bed with countless bulbs, including the Chionodoxa's seen in past posts. I had seen aphids on the scapes of a few of the bulbs, but recently there have been no sign of them. This could be attributed to the syrphids, whose larvae seek and destroy aphids.

Veronica umbrosa 'Georgia Blue' with a carrion fly, Chrysomya sp.
Carrion flies, or blue-bottle blow flies, were the other most common visitor. This are extremely fast flies, able to fly away in an instant with no warning. This made them extremely difficult to photograph, but not difficult enough  I suppose. The presence of these flies suggests how exposed the nectar is on these flowers. From where the flies are feeding, it appears the nectar is secreted at the base of the petals near the white ring in the center.

A large syrphid on Phlox subulata 'Blue Emerald'
Right next to the Veronica in the same bed is this moss phlox. It too has shown to be of interest to hoverflies, but to a lesser extent. Its floral morphology suggests Lepidoptera pollinators, but the presence of this fly contradicts that assumption, unless the fly is eating pollen instead of reaching the nectar. I must dissect one of the flowers to see if I can determine where the nectar is secreted, that is a definitive way to determine the most likely true pollinators. If the nectar is secreted deep down the corona, then it will require a long proboscis to reach it.

Alyssum montanum 'Mountain gold' with pollen eating mites
Next to the Phlox that is next to the Veronica is Alyssum montanum. This plant has also been of some interest to syrphid flies. What was really interesting to me was the presence of these tiny red mites, mostly concentrated on the anthers! I had never thought of mites as pollinators (perhaps they are indeed NOT pollinators) but here they are showing great interest in the pollen of these brassicaceous flowers. I strongly doubt their ability to pollinate the flowers, particularly because their small size and there is little reason they would visit the receptive tip of the stigma, let alone with any pollen to deposit onto it.

Quercus sp. with pollinators??
The oak trees are leafing out, and the flowers come with the leaves. The male flowers are borne in an inflorescence, specifically a catkin, while the females are tiny acorn-like cones (which upon fertilization will grow into acorns). The male flowers appear high up in the crown, while the female cones appear at almost any position. The trees are primarily wind pollinated. I noticed some movement high up in one of the trees earlier in the week, there appeared to bee bees (or something similar) moving from one branch to another, then another, at long intervals. This is not wasp behavior, so I used the zoom on my camera to get a better look. I combined the photos, and added arrows to highlight what I saw. Number 1 shows the back wings and a thorax of a bee or fly on a cluster of male catkins. Number 2 shows a clearer image of a male catkin. Number 3 shows a bee flying away from a flower cluster. If only the flowers were closer to the ground I could have gotten a clearer shot!

Hyacinthoides hispanica with honeybee
Bluebells are in flower now, and while they are more or less ignored in shady dispositions, they are attractive to bees in the sun. Bumblebees and honeybees are most common, while a few flies and solitary bees were also there.

A honeybee with full pollen load on Hyacinthoides hispanica
Bees were able to obtain both pollen and nectar from the flowers, often going upside down to get inside. This is curious behavior, quite similar to their behavior in Hyacinthus flowers.

Solitary bee on fruit tree (Prunus sp.?)
For the first time since we've lived here, this mystery fruit tree has flowered in profusion. We do not know what it is! We suspected it may be some type of cherry, it has been known to produce a few inedible mostly-seed tart bitter "fruits", even the birds ignore them. Yet this year, it has attracted the attention of countless bees, flies, beetles, and butterflies. It is sweetly scented, unlike our plum trees which were somewhat sweet, but musky.

Honeybee on fruit tree (Prunus sp.?)
This is an aging worker, as evident by her frayed wing tips. She was also slower to move to the next flower than most of the honeybees, enabling me to take a photo of her. Honeybees are surprisingly difficult to photograph, depending on what they are foraging for. If they are foraging for nectar, they will be easier to photograph generally because their bodies are still while they reach in to get at the nectar. When foraging for pollen, they move quickly from flower to flower.

Solitary bee (Nomada) on fruit tree (Prunus sp.?)
There were many interesting solitary bees on this tree, many of which I was unable to photograph. This small bee resembles a wasp, but differs in that it is covered densely with hair. The position of the wings is also an indicator, wasps tend not to fold their wings over, though this isn't a guarantee.

Tiny beetles on fruit tree (Prunus sp.?)
These tiny beetles were on many of the lower branches. Their markings were beautiful, though I must point out that they were so small I could not appreciate them until the photos were on the computer. These beetles were no larger than a large grain of rice.

Nomada on fruit tree (Prunus sp.?)

How many insects can you find?

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