Eupatorium & solitary wasps

Continuing the last year’s review – the first picture from the August folder is a Waist-threaded wasp feeding on Eupatorium perfoliatum. It seems that the Common Boneset is a powerful attractant of various solitary wasps, besides other pollinators. Last summer I started to do a little ‘inventory’; I missed a few but there is always the next summer!

For those already cringing at the word ‘wasp’ – there are many species of solitary wasps native to Ontario and elsewhere, which do not have an aggressive behaviour and serve an important role as pollinators. Plus, they also contribute to reducing the populations of various caterpillars, spiders, and other not so beneficial insects from your garden!

They are not easy to identify at species level, but at least they can be assigned to a particular genus within a family or subfamily (https://ncipmhort.cfans.umn.edu/bees#sectionb, http://www.toronto-wildlife.com/Insects/Bees_Wasps/Wasps/wasps.html ). For example, the large group of Threaded-waist wasps (with narrow or threadlike waists) are very easy to recognize. They are typically large in size and prey on various insects and spiders.

The Threaded-waist wasps belong to the larger group of so called mud daubers (Specidae, Crabronidae); the name is used because they all build their nests from mud. Mud daubers capture and place paralyzed spiders or caterpillars in the nest cells as food for their young.

Others like the Grass-carrying wasps (Isodontia), prefer to lay their eggs in nests above ground (hollow plant stems, abandoned galleries and other similar locations). Females carry blades of grass to their nests to prepare the brood cells where they also place ‘tranquilized’ tree crickets wrapped in grass for the future larvae to feed on: more cool pictures.

Along with these wasps, there is a whole micro-ecosystem built around the Boneset tiny, fragrant flowers: lie-in-wait predators like praying spiders and ambush bugs, bumblebees, butterflies, sweat bees and many others.
It is a fascinating spectacle!

Following the food chain, many birds and small mammals prey on the adult wasps too, and other insects can parasitize the wasps ground nests and/or eating their eggs, larvae or the spiders placed there as food.

We rarely think about the impact a single plant has on the garden ecosystem, don’t we?!