July 5, 3033

My lousy temporary camera, which does not have a flash that works, was worthless on this cloudy day. There were no bugs, anyhow. Why??

So I did a bit of bug reading to clarify something about St. John's Wort beetles from http://omafra.gov.on.ca/english/crops/facts/info_sjwbeetles.htm

The chemical most often connected with St. John's wort is hypericin, the chemical used as a "marker" for medicinal activity. Recent research has revealed that there are at least 50 chemicals in this plant with varied medicinal properties. Like so many plants that are used as medicines the valuable properties of this herb cannot be attributed to one single chemical.
Research has shown that both the larvae and adults accumulate hypericin that they ingest from the plants. The amount of hypericin in the larvae is enough to make them photosensitive and feeding habits seem to reflect this accumulation.
The elytra (protective wing covers) transmit almost no light and thus the hypericin cannot become "activated". Adults are reluctant to fly from plant to plant. When the elytra are opened during flight, light can penetrate the cuticle, activating the hypericin which becomes toxic to them. Adults move about only when threatened with starvation.

If I were a SJW beetle? Being threatened with starvation would happen in the early afternoon.

Posted by andreerenosanborn andreerenosanborn, July 05, 2022 22:21

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