Spraying for West Nile and diminished insect population.

To those who live in areas sprayed for West Nile, have you noticed a diminished population of butterflies and other flower-pollinating insects, as well as the flowers themselves? I'm talking about the reduction of the population of insects overall as a result of spraying for mosquitoes.

I walk about a mile and a half a day in a wild area near my house dominated by invasive Ligustrum sinense (Chinese privet), but there are also a number of meadows dominated by native plants that flower profusely in the spring. Of note are Antelope horns, Asclepias asperula, a milkweed with flower heads that resemble  green tennis balls. In most years these flower heads are full of hairstreak butterflies, bumblebees, and large milkweed bugs. In previous years I would see at least a dozen of each of these species during one of my daily walks. This spring, total, I've seen a total of two or three bumblebees, two or three milkweed bugs, and zero hairstreak butterflies.

Other species of butterflies are lacking as well. I've seen no swallowtail butterflies of any species, no pearl crescents, no variegated or gulf fritillaries, no American or painted ladies, no red admirals, no hackberry butterflies, 1 or 2 yellow Sulphurs, and no buckeyes, though it's early in the year for those. Honey bees also seem few and far between. I have two tickle-tongue trees, Zanthoxylem clava-herculis, in my yard that are usually preyed upon by caterpillars of the giant swallowtail butterfly. I normally see a half a dozen or so of these caterpillars a year, but this year none so far.


Caterpillars giant swallowtail butterfly, a welcome sight anytime.

There is a rain-fed tank that normally has several dozen dragonflies everyday, but this spring there are only three or four at a time. ( a tank is an artificial pond originally dug for cattle.)

As far as flowers go, the Larkspurs (Delphinium spp) normally number in the hundreds in the spring, this year, one flower. Can one attribute the disappearance of this flower, to the diminished insect pollinators?