Wasps: Introduction

categories: Pollinators Wasps Wasps Intro

revision date: 2023-03-24 12:00

A sphecid wasp, Chalybion sp., foraging on Rabbitbrush, picking up pollen
A sphecid wasp foraging on Rabbitbrush, picking up pollen.
Photo by: D.G. James

Biology

Closely related to bees, wasps are important pollinators although their importance varies between family, genera and species. Wasps are carnivorous during their development, only becoming avid sugar and carbohydrate seekers as adults. Wasps not only provide pollination but insect population control for the plants they visit for nectar: two significant ecosystem services. In general, wasps lack the hairiness of bees and therefore may be less efficient in picking up and transporting pollen. However, even relatively hairless wasps like yellowjackets and sphecids do possess fine hairs that can pick up pollen grains.

Wasps typically have short tongues (unlike bees) and are unable to reach the hidden nectar stores of deep-throated flowers.  Therefore, wasps tend to visit simple, flat flowers with accessible nectar like Umbellifers.  Wasps are the only pollinators for a surprising number of plants in at least six families, particularly orchids.  Tiny wasps, less than 2 mm in length, in the family Agaonidae are also the only creatures capable of pollinating some cultivars of commercial figs, an important tropical crop.  Other wasps are considered important pollinators of farmed crops of mustards, apples and pumpkins.  In some cases, wasps have been shown to be more important pollinators than bees.  A recent European study showed paper wasps were more effective pollinators than bumble bees in greenhouses.  Wasps are important contributors to plant pollination, which results in biodiversity and the proper functioning of ecosystems.  However, the paucity of data on wasps as pollinators in both natural and farmed environments currently precludes us from putting a value on their service as pollinators.