Surprised by the Early Spring Pollinators
photos and words by Chuck Nafziger - March 2015
 Cherry Tree From early on, there were a few hoverflies working the flowers, I think several species, but again, not in the numbers of the Tachinid fly, E. signifer. Hoverflies are pollinators as adults, depending on species, larva can be anything from rat tail maggots in sewage to predators of other insects.
 Hoverfly on hybrid red flowering current  Hoverfly on cherry blossom  Hoverfly on dandelion | We have had an unusually warm winter and early spring, and I was anxious to fill in a huge gap in my bug observations. I wanted to know who are the early spring pollinators, so in mid-February, I stuck my orchard ladder up into an early blooming cherry tree, the earliest flowers I have around my place. I had seen a few of the day flying early spring moths, Mesoleuca gratulata aka "half white carpet moth", around and expected them to be in the cherry tree in force. They were there in the blossoms, but not in great number. To my surprise, there was a huge number of tachinid flies doing the majority of pollination. I saw a few tachinid flies last summer, but this was orders of magnitude more. There in the cherry tree were lots of these, Epalpus signifer, aka "early spring fly." Tachinid flies are pollinators as adults, and as larva, they parasitize catterpillars. Tachinid flies, with their bottle brush butts may not be the prettiest bugs, but I am very happy to see them. Another tachinid fly, Dufouria sp., showed up a week later, but not in the great numbers of the E. signifer.  Mesoleuca gratulata moth  Hoverfly on cherry blossom  Hoverfly, Mallota tricolor on cherry blossom |
Almost all the early dandelions had sweat bees pollinating them. Sweat bees are small bees of the family Halictidae, looking a little like wasps. They are usually solitary ground nesters, laying an egg, provisioning it with pollen and nectar, and then leaving it. Sometimes in the late afternoon, it looked like the sweat bees were inactive, just sleeping in the dandelions.
 Sweat bee on dandelion |  Digger bee on Indian plum |
 Jumping spider next to Mason bees | My neighbor to the south heard about my bug photographing and studies, and gave me a great mason bee block. The mason bees started coming out just last week, first week in March, and now I am starting to see them on all the open flowers around here. (This is a photo of a jumping spider, one of a couple hanging around the mason bee colony on my porch. I think they are very cute.) I have also spotted a few honeybees in the last week. |
All through the time of the early bloom, there were a few bumblebees, but only a few. Bumblebee queens are the only ones to over winter and they have to produce broods before their numbers increase. The first broods must have already matured, because there are many more bumblebees now. They are competing for the few dandelion blooms around. I did spot one bee I think is a digger bee on an Indian Plum.
 Bumble bee on dandelion |  Mason bee |
| What a surprise that flies were doing the majority of pollinating before the bees came on line. I wish I had more flowers for them. The Indian plum, red flowering currents, dandelions and cherry trees have given our friends a start. I am glad to see the salmon berry blossoms opening and pear blossoms about to open, so our little friends do not go hungry. Lack of forage is one of the big stresses on the bee populations. Finally, here are some photos of a tiny, but quite interesting character. The first photo gives a size comparison of one of these flies next to a bumblebee leg. The other three photos are decent id photos. I asked Merrill Peterson, WSU entomologist, to identify it for me since I have seen a lot of these in the dandelions. It is of the family Empididae, some are predators, some eat pollen, they have interesting mating rituals. http://en.wikipedia.org/wiki/Empididae Being a bug voyeur, I hope to see this some day. |  Empididae fly next to a bumblebee leg |
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