St. James Farm is Humming

by Carl Strang

As the cold spells have become fewer and weaker, insects and other invertebrates increasingly have decorated the landscape at St. James Farm Forest Preserve. None decorate better than the butterflies.

A few American lady butterflies appeared early in May.

A few American lady butterflies appeared early in May.

The silver-spotted skipper attests to the presence of black locust trees on the preserve.

The silver-spotted skipper attests to the presence of black locust trees on the preserve.

Very early in the season I was seeing abundant grasshopper nymphs in the forest. I had a suspicion about them, which was confirmed as they matured.

The green-legged grasshopper is an early season forest species.

The green-legged grasshopper is an early season forest species.

Dragonflies increasingly appeared in the second half of May.

The most abundant dragonfly in recent days has been the common baskettail. Though they usually are seen on the wing, this one gave me a rare opportunity for a perched shot.

The most abundant dragonfly in recent days has been the common baskettail. Though they usually are seen on the wing, this one gave me a rare opportunity for a perched shot.

No baskettail this. It’s another early season species, a female dot-tailed whiteface.

No baskettail this. It’s another early season species, a female dot-tailed whiteface.

All these insects bring out the parasites and predators.

Epalpus signifer is a tachinid fly, a parasite of caterpillars.

Epalpus signifer is a tachinid fly, a parasite of caterpillars.

Morning dew highlights the abundant webs of bowl and doily spiders.

Morning dew highlights the abundant webs of bowl and doily spiders.

 

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Butterflies

by Carl Strang

Butterflies are the most conspicuous insects, and to the extent that they are representative, they are telling us that insects got through the winter in pretty good shape. Butterflies have been abundant and diverse this spring, both species that wintered here and ones that have migrated north. Earlier I mentioned red admirals in this context, and their congeners the American lady and painted lady butterflies have been showing up as likely migrants as well. A member of a species new to my experience appeared at Mayslake Forest Preserve last Thursday.

Obviously a fritillary, it seemed too big for a meadow fritillary and too small for other species of my acquaintance. Also, it lacked silvery spots beneath the hind wing.

My practice is to photograph doubtful cases when I can, and this time it paid off. The newcomer is a southern species known frequently to wander north, the variegated fritillary.

On Friday I saw 3 question mark and 2 mourning cloak butterflies.

One of the question marks, named for the pale silvery small markings on the underside of the hind wing.

That in itself is not all that unusual, as I have seen both species at Mayslake before. What seemed odd was, in this butterfly-rich spring, these were the first of both species I have encountered on the preserve. Both overwinter as adults, and back in March during the warm weather we experienced, I would expect to have seen them, especially with multiple sightings of both species happening now. What gives? Yet another little mystery to tuck away in memory.

Recent Insect News

by Carl Strang

Red admiral butterflies have attracted a lot of attention in recent weeks. We are seeing many more than usual this year. According to authorities, including Chicago’s Doug Taron in his blog, these are mostly migrants coming up from the south.

Red admirals have been appearing in clusters at Mayslake Forest Preserve. I am counting dozens on a typical lunchtime walk.

I wonder, though, how many are local survivors of the mild winter. It might be possible to find out, by doing chemical or isotope analyses of tissues. That method has been used, for instance, to determine where breeding birds spent the winter, but it would be an expensive study to undertake.

Another migrant which has begun to show up in greater than usual numbers is the American lady, a butterfly in the same genus as the red admiral.

Last week I saw a few syrphid flies which proved to be indistinguishable from one of the species that were abundant last fall.

According to references I accessed through the BugGuide website, both these and the autumn ones are Helophilus fasciatus.

I also photographed a small bee that is colored like a carpenter bee.

This may be the mining bee Anthophora abrupta. If so, the pale face makes it a male.

These have tunnel nests in clay banks. The most likely nearby location is the friary demolition site. When my back has healed to the point where I can be more mobile, I’ll see if I can find a colony there. That would confirm the identification.

September Invertebrates

by Carl Strang

The last days of September brought a couple butterflies to Mayslake Forest Preserve that I hadn’t seen in a while. One, an American painted lady, was an addition to the preserve insect list.

The other was the first eastern comma I have seen there this fall.

One day last week as I passed along the north savanna ridge top I heard a particularly loud tree cricket song coming from a Drummond’s aster beside the path, and was able to catch the singer.

Interpreting the antenna spots proved to be tricky in this, the best photo I got before releasing the insect. I had to conclude, though, that this was a black-horned or Forbes’s tree cricket, perhaps the palest I have seen. The only dark pigmentation was in his antennae and a brown double line down the underside of his abdomen.

Early in the month I had photographed this big orb-weaver on that same ridge top.

When I checked my references I found that there were at least a couple species that fit this ventral color pattern. I looked several times in subsequent days, but did not find the spider again to check her dorsal surface.

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