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by Don Smith
A member asked me about this at the November meeting and I hadn’t a clue but the following day the article appeared in the Yorkshire Post. Cryptocephalus coryii is a member of a large group of leaf-eating beetles and is a rarity with only 3 small sites in Britian. It is about 6mm long with yellowish to dark elytra: where the male has a black thorax the female has a red one. Ellerburn Bank Reserve has a similar rarity, the metallic green C. aureolus.
English Nature want to conserve the species but don’t know where or how the larva pupates. The larva constructs a case made of chewed leaf material which it enlarges and extends as it grows. Other insect larvae adopt similar tactics as, for instance, the case-bearing Clothes Moth. English Nature has hit on the idea of attaching a scrap of metal foil to the case and then searching the ground later on with a sensitive metal detector! Grand in theory, but I bet it will have left its cumbersome case far behind by the time it reaches its pupation site – if other case-bearing species that I have reared to adults are anything to go by.
In last year’s Newsletter I recounted the Slime Mould Physarum on the beech leaves in my leaf compost. This year around mid-October I noticed a grey circular patch the size of a dinner plate on the lawn. Close examination revealed that each blade of grass was studded with tiny grey spheres. There is no harm to the grass – Myxos are carnivorous animals eating bacteria and other scraps as they spread. The final stage is pure vegetable, the spheres being filled with spores. Having purchased the book The Myxomycetes of Britain and Ireland I identified this as Badhamia foliicola. However I took this, and some of last year’s leaves, to Colin Stephenson: he confirmed the species on the grass, but pointed out that the leaves bore the same fungus. So it wasn’t Physarum. He also identifed another Myxo on the leaves, tiny brown spheres on hair-like stalks, as Lamproderma arcyrioides.
Members may recall that at our last lecture I asked the speaker what value the alga conferred on its host, the polyp. It is very loose thinking, and quite unscientific, to assume that a particular organism has one identical relationship with the many unrelated plants or animals with which it is associated. I therefore decided to research the subject and quickly realised that carbohydrate-sharing had nothing whatever to do with the hydra-alga relationship. The alga concerned, a species of Chlorella, has extremely small cells and lives within the large digestive cells which line the interior of the polyp. It benefits from the waste products of its host’s metabolism. It also utilises the carbon dioxide given off as the host respires and through photosynthesis provides its own energy source. In so doing, like all green plants, it produces oxygen. Since the hydra has no respiratory organs this is beneficial, especially in high summer when oxygen can be severely depleted in the pond. A true symbiosis, then, where neither partner dominates or exploits the other, but where both benefit.
British Mammals asked readers of its Autumn 2000 issue to say whether or not they were in favour of re-introducing pine martens to England. They were once common, but were driven out by gamekeepers and survive only in Scotland. It has been shown that they could co-exist with pheasants and partridges reared for shooting. In Ryedale we have seen the otter return to our streams, and in our last issue we wrote about the re-introduction of the dormouse. Could the pine marten be next?