Why are there so few insects and spiders in San Francisco?
In any other city in the world, I encounter insects with 10-100x the frequency.
In any other city in the world, I encounter insects with 10-100x the frequency.
I think it is partially the cool weather that slows them down and the long dry season. It seems especially hard on the typical flying insects that tend to annoy people. Most of the insect life I've seen prefers to root around deep in the topsoil where it is presumably warmer and not as dry.
Western Europe is similar. Coming from New England it blew my mind they barely even know what insect screens are in France/Germany/Switzerland. Just an unbelievable lack of insects compared to the eastern US.
There used to be a lot. Half of all insect species are in decline. San Francisco State has researchers monitoring the decline of the insect population in the city itself. One of them can be reached for further comment:
Gretchen LeBuhn https://biology.sfsu.edu/faculty/lebuhn