Tuesday, 15 November 2016

More about Deadly Nightshade

A few months ago, in a blog called 'Hospital Poisons' (20 July), I drew attention to the fact that Deadly Nightshade, Atropa belladonna, grew in the grounds of Northampton General Hospital. It was still there when I visited earlier today; indeed I found another robust specimen. It was still bearing its glossy, purple-black fruits, 'girt by the persistent, spreading calyx'* and very tempting they looked too, for serving with 'lashings of ice cream'.
The glossy, black fruit of Deadly Nightshade photographed in the grounds
of Northampton General Hospital. 15 November, 2016
Presumably they will eventually be consumed by birds, but at the moment alternative fare is on offer.

All parts of the plant are very poisonous - or at least they are to humans. Other creatures may regard them as wholesome and delicious and sinuous mines formed by insect larvae in the leaves showed that they were quite acceptable.
Phytomyza horticola (?) has mined the leaves

I am reasonably certain that the mines shown are the work of Chromatomyia horticola #. This is a common fly and its widespread occurrence can be put down to that fact that the larvae are polyphagous, that is, able to feed on a wide range of plants. (Autophagous creatures feed only on a single species: the Heart Moth, Dicycla oo for example, feeds only on oak. And if the food plant becomes extinct, then so does the creature.) Polyphagy is really quite remarkable, as it means that the grub feeds on a wide range of plants, encountering many toxins and is able to cope with them all; indeed C. horticola has recently been reported on another very poisonous genus, tobacco. This fly is known also as a pest of plants in the daisy, cabbage, and pea family and, in some countries, has been the subject of much research as a consequence to the damage it can inflict on oilseed rape.

* Hutchinson, John. 'British Wild Flowers. Penguin Books, 1945

# Before any of my friends pick me up on it, I should say that recent research has shown that it is more appropriately called Phytomyza horticola.

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