Box Elder Bugs and Lady Bugs

     Eastern box elder bugs are in a family of insects called true bugs, and lady bug beetles are in another insect family known as beetles.  Though not closely related and having different lifestyles, box elder bugs and lady bugs have one major thing in common: swarms of adults of each species seek shelter in cold weather and frost in October in southeastern Pennsylvania, as elsewhere across the United States, east of the Rocky Mountains, to survive the coming winter.  Those great gatherings of both kinds of insects are impressive to see on October afternoons when they emerge from their shelters and are active in the warming sunlight.  But they quickly retreat again when the cold of October evenings set in.
     In spring, after their winter dormancy, female box elder bugs emerge from their shelters and suck the sugary sap of the leaves of ash-leafed maple trees, also known as box elders, silver maples and red maples in riparian woods along creeks and rivers.  And because they mated with males of their kind during the previous summer, each female lays many fertile eggs in bark crevices and other sheltered places on maple trees, then die. 
     Red male and female nymphs hatch from those eggs in the same summer and feed on the sap of maple foliage.  They become almost one inch long and dark as they grow, with orange-red undersides and reddish stripes on their upper thoraxes and wings.  This second generation of box elder bugs mates and the males soon die.  But the fertilized females live to form great gatherings in October to spend the winter in dormancy in sheltered places, such as hollow trees and in crevices between rocks at the ground's surface.
     Sometimes thousands of wintering female box elder bugs enter some barns, homes and other buildings.  And, although those insects don't bite, sting or eat anything all winter, most people don't like them in their homes.  They don't like the idea of swarms of bugs in their homes, no matter how harmless those insects are. 
     Unfortunately for wintering box elder bugs, peoples' homes are too warm for cold-blooded insects to winter in.  The warmth greatly increases the insects' metabolism and they burn up their bodies' food reserves before foliage develops on maple trees the next spring.  Wintering female box elder bugs in warm houses run out of energy and die before spring arrives.  It's best to get these bugs out of the house for the peoples' sake and the insects'.
     The cute, quarter-inch lady bug beetles also form great gatherings in October when they seek sheltered places to spend the winter in relative safety.  Their impressive swarms take refuge under dead and fallen leaves and logs, behind loose bark on standing trees, in cracks between rocks on the surface of the soil and other sheltering places. 
     The attractive adults of most kinds of lady bugs are red with black dots on their wing covers.  And they have black and white heads and thoraxes.  Lady bug nymphs are spindle-shaped, dark and red and have small spines that protect them.  Adults and young alike catch and eat aphids and other kinds of small, soft-bodied insects, protecting fruit trees and other plants from those potentially destructive insects.  Lady bugs are sometimes intentionally released among crop plants to rid those crops of harmful insects.
     Look for swarms of box elder bugs and lady bug beetles in sheltering places in October.  Those gatherings are impressive, and another natural happening when average temperatures each succeeding day drop and deciduous foliage reaches its peak of changing colors.