Saturday, July 09, 2011

Insects on Flowers

National Pollinator Week may be over, but the pollinators are still here. As long as they are here, I will be trying to photograph them. So here are a few insects that I photographed on flowers within the past week.

A common sight around garden flowers are Syrphid flies, which mimic bees and wasps. Some Syrphid flies resemble bees and wasps so closely that it can be difficult to tell the difference without looking very closely for the Y-shaped antennae and the stunted second pair of wings. Which species are present seems to change a bit through the season, though I have not gotten a good sense of this yet. This species, the Transverse Flower Fly (Eristalis transversa) seems to fly mainly in midsummer.

Not all bees are yellow and black. Some are green, especially bees in the family Halictidae, collectively known as sweat bees. There are several genera with green-colored bees, but I think this one is Agapostemon virescens based on range and the characters noted on BugGuide.

Some very tiny bees in the garden are small carpenter bees (Ceratina sp.). These normally nest in twigs rather than boring into wooden structures. Recently I watched a small carpenter bee search for a nest location. It stopped and looked into a few twigs before it finally found a suitable one. I am not sure if it was looking for a deep enough cavity or the right hole diameter. Or perhaps it was checking some other characteristic that is important to the bee but escaped my attention.

Another bee I have been seeing on flowers lately is this bee, which I think is a mining bee (Andrena sp.). There are over a thousand mining bee species, many of which look very similar, so it may not be possible to identify this one to species from a photograph. These bees are slightly smaller than honeybees and have a similar black and gold pattern. Some Andrena bee species can tolerate cold better than honeybees, so they are an important pollinator of plants in early spring.