Soldier beetles may be marching amongst your plants, and that's a good thing. These soldiers are likely to ambush aphids, caterpillars, corn rootworms, and other small pests. They are even reputed to attack cucumber beetles. As they lie in wait for prey on flowers such as goldenrod, they may feed on nectar and pollen but they do no damage to the plants. In fact, they are inadvertently pollinating the plants!
Belonging to the Cantharidae family of beetles, soldier beetles are nicknamed 'leatherwings' because of their soft, clothlike wing covers that resemble uniforms, often coloured yellow, orange or red and covered with short hairs.The beetles are elongate, soft-bodied and about 1/2-inch long. Adult females lay their eggs in the soil, and larvae usually spend the winter in damp soil or under loose bark. Larvae also prey upon the pests in your garden. Soldier beetles are attracted to goldenrod, hydrangea, catnip, milkweed and wild parsley, as well as Queen Anne's lace and basswood trees.
Although soldier beetles don't perform the same volume of pollination services as bees, they nevertheless are contributing to plant reproduction, plus eating pests, so they should be deemed welcome guests.
(Information sources: US Fish & Wildlife Service, National Sustainable Agriculture Information Service, University of Nebraska, Canadian Biodiversity)