species (Allecula morio) showed a p

species (Allecula morio) showed a positive correlation
with the size of the entrance, and a large entrance ought
to increase the temperature variability. This species may
prefer a dry microclimate, as a larger entrance will
reduce the humidity of the wood-mould.
Hollows higher up on the trunks were preferred perhaps
because the microclimate is different there and this
may influence the decay of the wood. Another possible
explanation is that bird nests are more frequent at greater
heights (Nilsson, 1984) and some species may prefer hollows
containing nests as the nutrient content might be
higher. Thirdly, there are probably generalist predators
(carabids and staphylinids) near the ground that are absent
higher up on the trunks. The preferrence for high hollows
has been recognised previously in some click beetles (Elateridae),
e.g. Ampedus cardinalis (Martin, 1989).
In previous studies, it has been found that O. eremita
and Larca lata prefer hollows with a large amount (>15
l) of wood mould (Ranius and Nilsson, 1997; Ranius
and Wilander, 2000) but the correlation with that variable
was not examined here since trees with