More Mayslake Insects

by Carl Strang

As we progress into the warm season, more and more insects jump, fly or climb into view. Most of the recent photographic subjects at Mayslake Forest Preserve have been moths or butterflies.

Monarch butterflies have received a lot of attention lately. Here a nearly mature caterpillar nibbles at a common milkweed flower.

Monarch butterflies have received a lot of attention lately. Here a nearly mature caterpillar nibbles at a common milkweed flower.

The beauty of moths is more subtle. This one is called the confused eusarca, a member of the inchworm family.

The beauty of moths is more subtle. This one is called the confused eusarca, a member of the inchworm family.

The prairies and meadows have produced dozens of tiger moths in the genus Haploa. These all seem to belong to two species.

I identify this one as a reversed haploa. A dark line extends from the midpoint of the leading edge of the forewing to the back corner of the wing.

I identify this one as a reversed haploa. A dark line extends from the midpoint of the leading edge of the forewing to the back corner of the wing.

This one appears to be a LeConte’s haploa. Here the dominant line goes out from the tip of the wing.

This one appears to be a LeConte’s haploa. Here the dominant line goes out from the tip of the wing.

Each species is represented by an array of confusing variations on these themes.

It hasn’t been just about moths. Here a Batyle suturalis longhorn beetle visits an ox-eye daisy.

It hasn’t been just about moths. Here a Batyle suturalis longhorn beetle visits an ox-eye daisy.

The most dramatic recent insect observation was this Laphria robber fly, with its prey, a honeybee. Laphria are bumblebee mimics.

The most dramatic recent insect observation was this Laphria robber fly, with its prey, a honeybee. Laphria are bumblebee mimics.

January Dandelions

by Carl Strang

This has been a strange winter, warmer than in recent years and practically snow free. Still, I was a bit surprised to see this on the Mayslake grounds on January 5:

This dandelion appears to have newly produced seeds, as well as a recently closed flower.

The skeptic in me hesitated to buy what I seemed to be seeing. Then, on the next day, I saw this:

A freshly open dandelion bloom at mid-day on Friday, January 6.

There’s no denying that this has to be one of the strangest winters of my experience.

The observation opened a little speculative door. Here is a European species, producing flowers when our native plants still are sensibly dormant. Such an ability makes me wonder whether dandelions specifically coevolved with the equally Old-World honeybees, which can remain active and will venture forth from the hive on warm mid-winter days.

Literature Review: Threats to Bees and Bats

by Carl Strang

I had been sort of vaguely following the story of problems honeybees have been experiencing in recent years with diseases and parasites. Then I saw a paper in Plos ONE that seemed to reveal progress [Bromenshenk JJ, Henderson CB, Wick CH, Stanford MF, Zulich AW, et al. (2010) Iridovirus and Microsporidian Linked to Honey Bee Colony Decline. PLoS ONE 5(10): e13181. doi:10.1371/journal.pone.0013181].

This hole in a red elm on the Mayslake mansion grounds has housed a honeybee colony for years.

This research group appeared to have solved the mystery of what has been causing collapse of honeybee colonies: a combination of pathogenic organisms, a virus and a microsporidian (single-celled fungus); apparently when separate, these microorganisms are not as devastating.

More recently a review of the problem, apparently written before the Bromenshenk et al. study came out, was released by the Department of Agriculture (CCD Steering Committee. 2010. Colony collapse disorder progress report. USDA Agricultural Research Service). The committee concluded that the disorder is attributable to a combination of factors rather than any single one. Disease organisms, parasites, and pesticides (especially miticides used to treat bee parasites) all may be contributors. Stresses resulting from domestic colony management and transportation practices also are possible contributors. None of this is invalidated by the Plos ONE paper. The immediate cause could be that combination of diseases, but the bees may be weakened by some of the other factors and so made vulnerable.

A separate concern has been raised about the impact of the big windmills used in power generation on migrating bats. Numbers of bats sometimes are found dead beneath those things. Canadian researcher Robert Barclay and colleagues have been looking into this problem, and a pair of papers they published in the Journal of Mammalogy in 2009 presented some of their results. In the first of these (Cryan, Paul M., and Robert M.R. Barclay. 2009. Causes of bat fatalities at wind turbines: hypotheses and predictions. J. Mammal. 90:1330-1340), they found that bat species are not all equally affected. Hardest hit are tree roosters and longer-distance migrants. More research is needed to find what brings bats to the turbines (random encounters, coincidental placement on concentrated travel routes, or attraction to the sound or another stimulus presented by the windmills).

This history-conscious bat is roosting inside Aldo Leopold’s famous Shack. Much of his Sand County Almanac was inspired by that site in central Wisconsin.

The second paper reported the start of this additional work (Baerwald, Erin F., and Robert M.R. Barclay. 2009. Geographic variation in activity and fatality of migratory bats at wind energy facilities. J. Mammal. 90:1341-1349). They monitored bats acoustically across southern Alberta. Bats concentrated their migratory travel along certain routes. Mortality depended on whether turbines were on these routes, and also on turbine height. The last set of data suggests a way to help the bats out through windmill design. Mortality was low on turbines 50, 80 and 84m tall; turbines intermediate between those extremes, at 65 and 67m, produced much higher mortality. Finding where the bats funnel and avoiding those places, and building either short or very tall windmills, can greatly reduce bat kills if these results hold up under further tests.

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