Letter: Oilseed rape keeps bees busy

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The Independent Online
PAUL SIMONS'S article on the effects global warming might be having on our insect population refers to the increase in honey yields which beekeepers are experiencing ('Consider the birds and the bees', Review, 12 December). I suggest that in many areas this has more to do with modern farming practices than global warming. Large acreages of oilseed rape have provided an abundant and attractive source of nectar for honey bees. In 1989, the year quoted by Paul Simons, one of my colonies adjacent to a field of oilseed rape produced over 100lbs of honey before the end of May.

In the past few years the introduction of earlier and later varieties has extended the flowering period of oilseed rape from a few weeks in May to between April and July. Apart from increasing yields, and the problems beekeepers have in extracting honey that sets very quickly, it is distracting bees from more traditional sources.

There is, however, an indicator of global warming which was not mentioned - the activities of moths. Having monitored moth populations in Essex, Kent and now Warwickshire since the late 1950s, I have noticed that many species are appearing earlier in the year to coincide with the optimum temperature for their emergence and the growth of their food plant. There also appears to be an increase in the incidence of second broods among many species, an occurrence which is usually dependent upon favourable weather conditions.

Paul Simons referred to the increased use of pesticides and herbicides and this certainly appeared to be instrumental in the decline in moth populations in the 1970s and 1980s. However, there now appears to be a reverse in this trend, and while it may in part be due to global warming, it has probably more to do with a move back to environmentally friendly practices.

Nicholas Bond

Stratford, Warwics