The Arnot Forest in in the northern part of New York state. The soil is poor for agriculture so mostly the land is left alone for nature to take over. Tom started watching the bees there in 1977.
In 1978 there were 9 wild colonies at an approximate density of one wild colony per square kilometre (I don’t know why he’s gone metric!) with an average distance between them of 780 metres (about half a mile). Varroa arrived in 1990. In 2002 there were 8 colonies despite the untreated Varroa.
How do they survive without treatment? Bees resistant? Nest spacing? Nest type (high up in hollow trees)?
Workers are smaller now than they were in 1978. 35% of fallen mites are damaged. Tom (and students?) tested VSH (Varroa Sensitive Hygiene) behaviour by freeze killing brood, from which they deduced that the workers are good at uncapping Varroa infested cells.
Tom described an experimental array of 2 groups of 12 colonies with no Varroa treatment. One group was closely clustered, the other spread out. The clustered group had lots of bees drifting between colonies, the spread out group about 1% drift. None of the clustered colonies was alive after 2 years whereas 5/12 hives in the spread out group were still alive then.
The cavities selected by the bees for their nests were small compared to hives, about 40 litres (a bushel), so the relevant factors for comparative success of the wild bees are colony spacing, nest size and small cell size. The propolis coating of the inside walls of the wild colonies acts as an ‘anti-microbial shroud.’
After the lecture I gave Tom a copy of Bees vs People, the book of my poems about bees and their keepers.