Indiana is currently experiencing drought conditions. Soils are very dry, grass is turning brown and dormant. The dry conditions will have adverse effects on some insects.
Most gardeners recognize the Japanese Beetle, a copper and green beetle that clusters on flowers. The Japanese Beetle adults damage flowers (especially roses) by feeding and may defoliate grapes as well as ornamental and fruit trees such as plums. The Japanese Beetle, as its name implies is an invasive species from Japan that arrived on the East Coast of North America in the early 1900s.
Japanese Beetles spend their immature life underground feeding on the roots of grass. Adults lay eggs in the summer and larvae feed until late fall. As winter approaches, they burrow below the freeze line to survive the winter. In Spring, they move back into the root zone, feed on the grass roots and finish development. The Japanese Beetles do best on a well watered lawn. Mortality is higher if soil is too dry. Low soil moisture has a direct effect of dehydrating the beetles and an indirect effect of making plants less nutritious.
Japanese Beetle females prefer to lay their eggs in areas with high soil moisture and at very low levels of soil moisture, will not lay eggs at all. Drought can negatively impact Japanese Beetle populations in the following year by providing less habitat. Homeowners may not like the looks of their brown lawns, but the Japanese Beetles don’t like it either.
Japanese Beetles
I have noticed a decline in the number of butterflies in my area and wonder if the drought and/or high heat have effected their numbers. For instance, extremely parched foilage not providing enough moisture and other wise sustenance to larva. I have also noticed changes in butterfly and other insect behavior during the hottest part of the day.