Blue sky, still air and the winter sun have lifted the heavy overnight frost. Cavenham Heath contains one of the largest blocks of heathland and acid grassland in the south-west Breckland, but the path from the car park starts in a predominantly birch woodland. Tearing a weathered birch polypore (Fomitopsis betulina) from a standing trunk, I fumble through its white flesh. It is shot through with burrows and in places under the pale leathery skin it is dry and powdery, while elsewhere the fungus retains a tough marshmallow consistency.
The first beetle revealed is a tenebrionid, the common darkling beetle (Nalassus laevioctostriatus). Some members of the tenebrionid family are familiar domestic beetles – mealworms and flour beetles, for instance. Britain’s 30 or so wild species live in dead wood, sand dunes and a range of other habitats.
Then a bulbous shiny beetle the size of a garden pea pops out. It is blackish with two broad orange-yellow stripes on the elytra, and similarly coloured tips. This is a considerably rarer darkling beetle – Diaperis boleti. A specialist of this habitat, it has been spreading in recent years along the Suffolk coast, in Surrey and in the New Forest.
Finally there are some tiny brown beetles, which are later revealed to have two bizarre vertical tabs, one on the nose and one behind the head – Cis bilamellatus, an Australian species first found here 133 years ago and now widespread.
Under a large birch log out on the grassy heath, I find a midden of harlequin ladybird elytra and wings. The Asian harlequin is a particularly unwelcome invader that has ripped through Britain’s native ladybirds. Ladybirds are protected from predation by distasteful chemicals and positively unpleasant alkaloids, so finding the remains of more than 45 in a pile is unexpected. Alongside are gathered grass and a hole in the ground – small mammal activity, but it’s not clear if it is a vole, shrew or mouse. Two weeks previously a report was published of a similar event implicating a wood mouse. Perhaps one of our predators has found a new food source – clumps of hibernating harlequin ladybirds.
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