I have been visited the past few weeks by an interesting insect that arrived in the thousands, attracted to my blanket flower and then rabbitbrush. You too may have noticed these orange and black beetles and wondered what they were doing and where did they come from.
This beetle belongs to a family known as soldier beetles, cantharidae. These are beetles in which adults feed primarily on flower pollen, sometimes flower nectar. Beetles of this family generally have dark yellow, orange or red elongated bodies. Adults of my particular beetle are about half an inch long with a dull yellow-orange base body color with a large black blotch on its thorax, and on the anterior and posterior of its wing covers or elytra.
This species, chauliognathus pensylvanica, or goldenrod leather wing soldier beetle, is especially attracted to yellow-flowered plants such as goldenrod and rabbitbrush. Unlike most beetles which have hard forewings or elytra, soldier beetles have soft forewings. Most immature soldier beetles are predators, living mainly in leaf litter or in the soil. Adults can be predacious on insects feeding on flowers or pollen feeders like the one I found.
These are interesting beetles to watch. They are very active when warmed up by the sun. Most adults are coupled, with the male on top. Those single beetles are most likely males and appear to be frantically looking for a female mate. You can’t believe the level of activity going on in my rabbitbrush. They frequently fly from flower cluster to flower cluster in their search for mates. Once coupled, they become much less active. I do have a lot of blooming rabbitbrush but to tell the truth, I have never seen so many soldier beetles cavorting in my garden. Maybe our spring rains increased their survival and numbers.
And by the way, these beetles are not harmful to your garden landscape. The only problem I observed was because there were so many and their activity so rambunctious, honeybees were having difficulty finding an unoccupied area on a flower cluster where they could feed in peace.
Don’t forget to reserve Oct. 5 or 6 to visit Cedaredge’s AppleFest. This is a very popular event with over 200 vendor booths. The Cedaredge Tree Board and the Colorado Master Gardeners will again share a booth on Main Street. Stop by with your gardening questions. Enter our drawing for either a garden insect book or a weed identification book. Both have lots of color pictures. Try your luck with our insect identification contest, the “good, bad and ugly.” At least stop by to visit. We would love to share gardening experiences.
Jim Leser retired to Cedaredge after a career with Texas A&M University Extension in entomology. He is a member of the Cedaredge Tree Board and a Colorado Master Gardener.