outdoor lighting

[ian.woiwod]

I suspect that the idea that low pressure sodium lights are preferable to
mercury vapour in terms of their effect on moth populations is one of those
urban myths. Although moths are not attracted to sodium lights they do appear
to be very effective in inhibiting flight and thus either sterilising large
areas or forming inpenetrable barriers to normal movement. The effect of this
on moth populations is likely to be as large or even larger than MV lights
which only inhibit flight in the immediate vicinity of the bulb and often
attract mainly males.

 In the UK there is at least one species, Ourapteryx sambucaria, the
swallowtail moth, which seems to be oblivious to the sodium lights and goes
about its business as usual, but this is not typical. However I am not aware of
any good quantitative data on the efffects of increased urban lighting on moth
populations and would welcome any references.

Ian.Woiwod at bbsrc.ac.uk