Showing posts with label pollinat*. Show all posts
Showing posts with label pollinat*. Show all posts

Sunday, May 24, 2015

Violets 2 - Viola spp. - Violettes 2

When I went off to visit with my parents in the upper Gatineau region, I encountered a couple of species of violet that I haven't already talked about in my previous post about violets. So today I'm going to add those species to the list of currently-blooming violets.

Viola labradorica
First up, we have Viola labradorica (aka Viola conspersa, alpine violet), which actually I've been seeing in lawns in Montreal, too. This little pale purple violet is native to eastern North America (US range map here, Canadian range map here), and is threatened in Illinois [1]. It is secure across Canada but sensitive in Prince Edward Island, may be at risk in Saskatchewan, and its status is unknown in Newfoundland and Labrador [2].

Viola labradorica flower
The leaves and flowers of V. labradorica are edible [3]. It is sometimes used in gardens as a ground cover in shaded areas [4].

Viola macloskeyi
Next up we have Viola macloskeyi (northern white violet). This little violet is native to North America and has a very broad range (range map here). It does not have any listed protected status in the US [5]. The species is sensitive in the Northwest Territories, Nunavut, and Alberta, and it may be at risk in Saskatchewan [6]. Its status has not been assessed in Newfoundland and Labrador, and it is secure in the rest of its Canadian range [6].

Viola macloskeyi flower
This species is distinguished from Viola blanda, another white violet, by its scent [7].

One of the things that may jump out at you when looking at my viola photos is that most of them are "bearded" - meaning that they have fine hairs along the inner portions of the petals. So what's that all about?

Well, those fine hairs are there to increase the odds of pollination. While the pollinator is pushing its way up the throat of the flower to get at the nectar in the spur (which extends behind the flower), its body is rubbing over the hairs and the pistil of the flower. Pollen that has already been deposited on the belly of the pollinator will be transferred to the pistil, while pollen from the flower will be spread over its sides and belly to be carried to the next flower.

So those hairs aren't just decoration; they help the flower increase its chances of spreading its genes.

Monday, May 4, 2015

Insect Pollination: The Bees are Out Full Force

On my walks on May 2 & 3, one of the things that was hard to miss was the enormous amount of pollinator activity. I did not see any Apis spp. However, I did see a remarkably wide range of solitary bees, some syrphid flies, a single Bombus sp. queen, and of course the Bombylius major I posted about on Saturday. I also saw a single Pieris rapae (cabbage white butterfly) in the cemetery.

I am not able to identify all of the species that I have seen, but I took a number of photographs. It took a great deal of effort to get these shots. It's at times like this that I daydream about being able to buy a telephoto lens. How much easier it would be to take photos of pollinators if I didn't have to get my camera within a few inches of them!

Bombus sp. queen on Trillium grandiflorum
This Bombus sp queen was relatively easy to photograph, as she was rather sluggish. I discovered her pollinating some barely opened Trillium grandiflorum. She was so sluggish, in fact, that I actually managed to catch her in flight (shown below). She appeared to be focusing on the retrieval of nectar during the period I was observing her (note her empty pollen baskets).

Bombus queen in flight, just leaving Trillium grandiflorum after collecting nectar
This Bombus queen, however, was the only bee I didn't have to fight to get photos of this weekend. The rest were considerably faster and shyer.

One individual on whom I at least have a reasonably positive I.D. is this solitary bee visiting Scilla siberica; I believe this to be Andrena barbilabris.

Andrena barbilabris (?) on Scilla siberica
Another individual whom I believe I have identified reasonably reliably is this solitary bee, who I believe is Halictus ligatus, shown here visiting Tussilago farfara:

Halictus ligatus (?) on Tussilago farfara
There are a few more species I managed to photograph as well, but which I have been unable to identify as yet.

Unidentified solitary bee on T. farfara
Unidentified solitary bee on E. americanum
Unidentified solitary bee on S. siberica
There were many more than I managed to photograph over the weekend; I counted at least eight visibly distinct species of solitary bee pollinating the T. farfara, and there may well have been more depending on how visible and obvious the distinguishing characteristics of the species are; without a microscope and a specimen, it can be very difficult to judge. At any rate, the solitary bees especially were numerous and varied.

Saturday, May 2, 2015

Insects are Harsh: Large Bee-Fly - Bombylius major - Grand bombyle

It was remarkably nice out today, so I decided to head out to the mountain with my camera to enjoy the weather and to see if the insects had started to wake up. They certainly have! In the various places where the spring ephemerals were in bloom, virtually no flower sat untouched for more than a few moments while I was observing. The pollinators are out in full force. I didn't see any Bombus spp or Apis spp, though. Just a variety of solitary bees, some Syrphid flies, a single Pieris rapae (cabbage white butterfly), and of course a large bee-fly.

The large bee-fly is a member of the Bombyliidae (bee flies) family, a group of bee flies (Order Diptera). Though they are flies, they are bee mimics. Mimicry generally is selected for when the mimicry is of a species to which predators are either indifferent or avoidant.

Unfortunately, the Bombylius major individual I spotted today pollinating T. farfara in the Notre-Dame-des-Neiges cemetery refused to hold still. It's quite tricky to locate an individual, pursue it until it lands, orient the camera in close without scaring the insect away, focus correctly, then take the photo. So, I have only the one photo, which is not great.

B. major pollinating T. farfara
In any case, B. major is a great example of the harshness of nature. B. major is a parasitoid of ground-nesting insects [1] (particularly solitary bees of the genus Andrena) [2]. The major difference between a parasitoid and a parasite is the outcome for the host. A parasite may reduce the fitness and competitiveness of the host, but doesn't assure its death or inability to reproduce; a parasitoid will eventually either sterilize or kill its host.

So B. major's basic method is to seek out ground nests (eg those of Andrena spp.) and deposit their eggs or larvae nearby so that they can crawl into the nest. The larvae then will attach themselves to the Andrena young, feed off them, and eventually kill them. Failing this, B. major will deposit the larvae on flowers that Andrena queens might visit, so that the larvae might be carried off into the nests. [3]

I witnessed a huge number of solitary bees visiting T. farfara today, so this B. major individual will have no shortage of potential hosts for its young.

Harsh.

Bonus photo of S. siberica, just to have something pretty to look at in this post:

Scilla siberica