Flower flies

Syrphid fly on flower
Helophilus fasciatus on Lindley’s aster (Symphyotrichum ciliolatum) looking for pollen and nectar.

On a warm late summer day if you walk into a field of flowers particularly yellow flowers like goldenrods you might think you have stepped into a swarm of bees or wasps. There is intense buzzing and many small yellow and black insects on the flowers and flying all around you. But despite all appearances these are not bees or wasps at all. They are flies. Syrphid flies, also known as flower flies and hover flies, to be more exact, and there are many species that mimic bees and wasps, a good strategy if you are trying to fend off predators.

Syrphid flies are true flies in the Order Diptera (“two wings”) and Family Syrphidae. Adult syrphid flies feed on nectar, pollen, and sugary secretions from aphids. You can use their love of sweets to attract them with mixture of sugar or honey and water sprayed on surfaces like tree trunks in open areas. When moving about on flowers syrphid flies assist in the pollination of many plant species including crops we grow.

The larvae have more varied diets depending on the species. Some syrphid fly larvae feed on decaying plant matter, damp wood (perhaps for the bacteria and fungus which are more nutritious?), and subterranean parts of plants. Others prey upon aphids, scale insects, thrips, and similar sap-sucking insects and can be beneficial in crop fields and gardens. Some species lurk in ant nests where they disguise themselves with chemical secretions and eat ant larvae.

Syrphid larvae in the tribes Eristalini and Sericomyiin live in muddy stagnant water, even cesspools, where they feed on detritus. A long breathing tube from the anal segment pokes above the water to access the air. This long breathing tube has earned them the name “rat-tailed maggots”.

I recently bought “Field Guide to the Flower Flies of Eastern North America” and have found it very helpful in figuring out species of syrphids that live in my area. The book is well illustrated and includes descriptions and range maps. In the descriptions, the authors have included flowers that species typically visit if known. I have been able with this book to identify three syrphids (Eupeodes americanus, Sericomyia chrysotoxooides, Toxomerus marginatus) that had been in my “unknown” files for several years. And I’ve identified three others I photographed last week (Eristalis dimidiata, Eristalis transversa, Sphaerophoria philanthus).

Below is a small gallery of some of the syrphid flies I’ve seen here over the years.

SOURCES

Field Guide to the Flower Flies of Eastern North America. Jeffrey H. Skevington and Michelle M. Locke. Copyright 2019 Princeton University Press.

Homaemus aeneifrons – Bronze-Headed Shield Bug

Early Sunday morning I saw a group of bronze-headed shield bugs (Homaemus aeneifrons) sunning themselves on the seed heads of Canadian hawkweed (Hieracium umbellatum). The previous night had been very cool with temperatures dipping to 40 degrees F and this cluster of seed heads facing due east into the sun was a perfect place to warm up. In all, there were six bugs catching the early morning sun.

Homaemus aeneifron is widespread in North America occurring as far south as Kansas and Arizona and as far west as Alaska, British Columbia, and California. It is frequently found in moist meadows and weedy areas. Some reports state that it feeds on grasses and sedges (Carex) and rushes (Juncus) but one has it feeding on Monarda fistulosa (wild bergamot) and Oenothera biennis (evening primrose). These on hawkweed did not appear to be feeding. Beyond catching some rays it was hard to say why they were all there.

CLASSIFICATION
Kingdom: Animalia (Animals)
Phylum: Arthropoda (Arthropods)
Subphylum: Hexapoda (Hexapods)
Class: Insecta (Insects)
Order: Hemiptera (True Bugs, Cicadas, Hoppers, Aphids and Allies)
Suborder: Heteroptera (True Bugs)
Infraorder: Pentatomomorpha
Superfamily: Pentatomoidea
Family: Scutelleridae (Shield-backed Bugs)
Subfamily: Pachycorinae
Genus: Homaemus
Species: aeneifrons (Homaemus aeneifrons)

SOURCES

Bug Guide

Williams, Andrew H. 2004. “Feeding Records of True Bugs (Hemiptera: Heteroptera) From Wisconsin,” The Great Lakes Entomologist, vol 37 (1)

Thomas, Donald B.; Werner, Floyd G. 1981. Grass Feeding Insects of the Western Ranges: An Annotated Checklist. Technical Bulletin (University of Arizona, Agricultural Experiment Station) No. 243

A tremendous increase

Digrammia mellistrigata
One of the latest additions to the checklist is Digrammia mellistrigata (yellow-lined angle) a moth in the Geometridae (inchworms).

Since I last posted on the moth species diversity (a very long time ago) the list has gone from 270 to 761 species and will very likely continue to grow until winter puts a stop to insect activity outdoors. Some species were to be expected as they are common and widespread but there have been nights and a few days with interesting surprises. Eventually, the number of new additions will level off and then fall as the actual number of species is approached. But for the next year or two, about 50 new species will probably be added each season. Just in 2022 I’ve added 50 more species with July being the best month with 21 species. I’m not going to go through the whole list of new additions but below is a small sample of my favorites from the last few years. In some future posts I’ll be covering some unusual species occurrences while others will cover groups such as new Geometridae or new Crambidae I have found.

2018

Cucullia convexipennis larva
Metanema inatomaria

2019

Dejongia lobidactylus
Datana ministra

2020

Epermenia albapunctella
Acronicta lepusculina larva

2021

Schinia septentrionalis larva
Darapsa choerilus ( Azalea Sphinx Moth)

2022

Elophila ekthlipsis
Plagodis phlogosaria

I went up a hill

A view of a mountain from the mountain on a section of the Superior Hiking Trail located north of Little Marias, Minnesota. I’d really like to get to that other mountain sometime. It looks interesting.

Or maybe a mountain. Hard to say but there was at least one point where the elevation above the surrounding terrain was just a little bit above 1,000 feet or 1,613 feet above sea level and so 1,010 feet above Lake Superior if Google Earth is to be believed. I don’t even know if this hill or mountain is named. I’m sure that somewhere it is on a map with a name. This mountain is on a part of the Superior Hiking Trail, a 310-mile long trail that stretches from the Minnesota-Wisconsin border southwest of Duluth to the US-Canada border in northern Minnesota. This trail section is known as Section 13.

I’d been planning this day hike for several weeks intending to get to that other mountain in the above photo. Google Earth showed a spur from the main trail going to it. So early one morning in July I parked my vehicle in the trailhead lot and began my ascent. I got as far as the top of the mountain that day but turned back since my plans were only to do a little reconnaissance and get a feel for what this place was like. The next day I came back and continued past my first stop.

This is where I made my first stop. It’s a long way down. The rocks are almost entirely anorthosite which is a very hard plagioclase feldspar. The hardness of this rock resisted glacial scouring better than the relatively softer rocks overlaying it resulting in a series of peaks known as the Sawtooth Mountains because of their sharp profiles.

The climb is very steep in most places but doable in ordinary hiking boots. I got to where I made my first stop the day before and took a short break for some lunch and water. Then I continued on towards Camp 13 and then beyond it to where the trail descended into a deep gorge. According to the map near the bottom of the trail in the gorge is a spur that loops around the other mountain. Well, I looked for it as I hiked along the trail but never saw it. Maybe the map is wrong? I think so. The rest of the trail followed pretty much where the map said it would. When it opened up onto an expansive marsh crossed by a rickety footbridge I figured it was time to turn back. Besides, I had homemade pizza and some cold IPA back at the national forest campsite where I was staying and felt I could really use those. And there was that sci-fi book I was working my way through, too.

So, I didn’t get to the other mountain that day. I’ll give it try next year. In any event, I had an interesting and pleasant two days time trekking up and down the hill (or is it a mountain?), saw fantastic scenery, and found some interesting insect and plant life, too.

Above are few examples of plants and insects found in a small marshy woodland vernal pool just off the trail. The clustered bur-reed (Sparganium glomeratum) is an odd bur-reed that often grows in woodland vernal pools rather than lakeshores and rivers.

In the gorge I found several caves that had formed when huge fallen boulders had crashed upon each other. Some were almost big enough to stand in.

And I found insects, too. All of these were on one big-leaf aster flower. There are two moths (Scythris? and Landryia?), a bug (Plagiognathus obscurus), and a bee (Family Halictidae).

And, finally this plant, Actaea rubra (red baneberry) but with white instead of the usual red berries. It was common along the trail.