Tag Archives: aphid eater

A Sedgesitter

This was Wednesday’s bug of the day. I’m a day behind writing up my post. Although I have tried to get out for a quick bug search every day, it’s been overcast and/or drizzly here this past week. I was excited to see this little fly hunkered down on a twig of our fruitless cherry tree, the tree that I whacked off as an unwanted upstart for several years before I discovered how interesting it is.

Western Forest Sedgesitter, (Platycheirus trichopus), I believe

That tree is a mini ecosystem: floral nectaries that feed the aphids, aphids, slave making ants that have fights to the death (winning) with the carpenter ants that try to invade our home every spring, and the birds that rip the leaves apart trying to get the aphids. Now I can add Syrphid flies to the list!

That’s what this is. A syrphid fly. Syrphid flies eat aphids. It would make perfect sense for this adult to lay eggs on the tree, though I’m not sure what would happen because the ants that farm those aphids are certainly willing to die defending them. I could definitely see the ants overtaking the syrphid fly larvae. Nevertheless, the fly flew off. Somewhere.

I believe this particular fly is the Syrphid fly species Platycheirus trichopus, the Western Forest Sedgesitter. While difficult to ID to species, I did reference the helpful ID guide by fly expert, Even Dankowicz. https://docs.google.com/presentation/d/19F1qRGpmNDgaGE13M2SMUBlI846JicTOYjIescjVTHw/preview?slide=id.g8918834f0e_0_92

This species, as mentioned earlier is pretty small at only about 6.8-9.4 mm. Geographic distribution ranges from the Rocky Mountains west from Alaska to Mexico (bugguide.net). Adults of this genus are known to feed on the pollen of wind pollinated plants like Willow (Salix sp.) and various grasses (Poaceae), and sedges (Cyperaceae). It is believed they are better adapted to activity in cooler temperatures and that fits with yesterday’s rather gloomy spring day.

Thanks for reading!

References:

Dankowicz, Even (2023). “Common Pipizini, Paragini, and Bacchini Species of the Southwestern U.S. (CA NV AZ UT NM CO)”The Fly Guide: Field/Photo ID for Flies. pp. 9–10.

Bugguide.net. 2025. Syrphidae. https://bugguide.net/node/view/196

Western Calligrapher (Toxomerus occidentalis)

I sat outside today in the sunshine, forced convalescence if you will, exhausted and achey after getting my Covid Omicron Variant booster vaccine yesterday at the San Juan County Fairgrounds. My outdoor time was unfortunately cut short because we have been inundated with construction development noise. I’m fairly certain I will be forever challenged to have an amiable relationship with our newest neighbors. In part, because they sited their VACATION home, right in front of our view. Mind you, they could have moved over 100 feet and we would not have to look across the top of our driveway at their newly constructed 2nd home. It has definitely impacted us. We’ve lost a lot of our privacy out here in the woods. It was never my desire to have close neighbors. I am a bit of a recluse….which is what the new neighbor said about his wife, yet, it begs me to ask again, WHY DID YOU BUILD YOUR HOUSE RIGHT ON TOP OF US?

Oh, and the jackhammering! That noise is enough to make a person homicidal. We had an entire summer of jackhammering from the former owners of that property. Really, truly, that property should never have been zoned for development. Not any development. It’s partly (half) wetland, and the other half is bedrock. Imagine the task of trying to excavate enough to bury your septic lines down the hill when you have solid bedrock! Also, our house is on that same shelf of bedrock, so the hammering shakes the walls and vibrates the floors of our home in the process of all this construction. The development on this lot has gone on for multiple years. I’m really tired of the disruption.

I digress. Sorry, I just had to vent. San Juan Island would be a much friendlier place for wildlife and bugs and such if we didn’t allow anyone to build a 2nd, or 3rd home here. We are outgrowing our space and it isn’t pretty.

Here’s my bug of the day. This beauty is a Western Calligrapher Fly (Toxomerus occidentalis). I was mesmerized watching it rest on the mint leaf. The patterning on the dorsal side of the abdomen reminds me of some sort of totem design.

The adults of this fly species are pollinators. They lay eggs on plants near aphids and when larvae emerge they are predatory on the aphids. It is believed that late instar larvae overwinter, pupation takes place in the soil cavities in the spring and adults emerge later in summer. The name for this group of flies comes from Greek toxon ‘bow’ + meron ‘thigh’ (refers to the bow-shaped hind femur). You can see the curve in the first photo below, circled in red. Something else interesting pertaining to the adult coloration I found on bugguide.net: “Colors vary with overall temperature during pupation: if it was hot, the yellow/orange increases and the background becomes lighter, but if it was cold, the dark/black increases and the yellow/orange becomes darker like the background.”

Enjoy the last few days of sunshine and embrace our native pollinators. We are heading into the dark part of the year. For those of us who live here year round, you know what to expect. Lots and lots of rain.

Thanks for reading!

Western Calligrapher Fly (Toxomerus occidentalis)

Western Calligrapher Fly (Toxomerus occidentalis)