Family: Chrysididae, Pompilidae, Scoliidae, Sphecidae, Tiphiidae, Vespidae, Ichneumonidae, Chalcidae, Braconidae
Wasps are flying insects and are often observed visiting flowers throughout blooming periods. Like all insects, wasps have three pairs of legs, antennae, and three body segments called the head, thorax and abdomen. Wasps can be distinguished from bees by their pointed lower abdomen and a narrow waist called a petiole, between the abdomen and thorax.
- Similarly to bees and ants, wasps are social insects in the order Hymenoptera.
- Certain species of wasps visit flowers for nectar and can facilitate cross-pollination by transferring pollen between plants.
- In addition to their role as pollinators, some predatory and parasitic wasps act as natural enemies of insect pests.
Paper wasp (Polistes metrica) visiting a flower.
David Cappaert, Bugwood.org
While not obvious pollinators, some wasp adults visit flowers for nectar and inadvertently facilitate pollination. Since wasps don’t have abundant body hair like bees, they are generally considered less efficient pollinators than bees. Nonetheless, in some plant systems wasps are important pollinators. Wasps are generally described as specialist pollinators since they are selective in their flower choice, typically visiting flowers of few plant species.
Spider Wasp (Anoplius americanus trifasciatus) visiting a flower.
Fitz Clarke, Bugwood.org
Giant ichneumon wasp (Rhyssa persuasoria).
Boris Hrasovec, Faculty of Forestry, Bugwood.org
Baldfaced hornet (Dolichovespula maculata) nest.
Steven Katovich, Bugwood.org
Wasp size varies among species. Braconid wasps (family Braconidae) are relatively small and typically do not exceed 1.5 cm (0.6 inches) in length. Some wasp species, like those in the family Pompilidae, can grow over 5 cm (2 inches) in length. Wasp coloration also depends on species, ranging from yellow and black, to shades of brown and red, and even an iridescent dark blue.
Although bees are considered more effective pollinators overall, wasps are the primary pollinators in some plant systems. For example, there are at least 100 species of orchid that depend on wasps for pollination. These orchids are “sexually deceptive” and mimic the chemical and morphological features of female wasps. As a male wasp attempts to mate with an orchid, it picks up pollen which can then be transferred to other plants.
Moreover, there are roughly 1,000 species of fig tree that can only be pollinated by fig wasps. In this unique symbiotic relationship, reproduction of the wasp also depends on figs. A female will enter a fig through a small hole, causing her wings to tear off. The wasp then lays eggs in the fig and dies. Hatched larvae then feed on the fruit from within, eventually pupating into adult wasps. Male wasps then mate with female wasps and burrow a hole through the fig through which females can now exit, transferring pollen to the next fig tree as the reproductive cycle continues.
Life History and Habits
- All wasps undergo complete metamorphosis, meaning they have four life stages: egg, larva, pupa, and adult.
- Unlike some bee species, wasps do not produce honey.
- The stinger of a wasp is a modified ovipositor, which is a structure used for egg laying.
- All bees and wasps produce venom. The venom is harmless to humans who don’t have an allergic reaction to stinging insects.
- Wasp life history depends on the species. Some wasps are nest parasites that nourish their young by stealing food resources from other nesting wasp or bee species.
- Other wasps, like those in the family Ichneumonidae, are parasitic, laying their egg on an arthropod host where the juvenile wasp develops by feeding on the live host, eventually killing it.
- Wasps in the family Vespidae are social and live in colonies with hundreds or thousands of individuals, all of whom are the daughters of a single queen.
Encyclopedia Britannica. 2022. Spider Wasp. Encyclopedia Britannica. Available www.britannica.com/animal/spider-wasp
Encyclopedia Britannica. 2022. Braconid. Encyclopedia Britannica. Available www.britannica.com/animal/braconid
Espindola, A. & Hooks. C. 2017. Wasps, Surprisingly Cool Pollinators. Maryland Agronomy News, University of Maryland. Available blog.umd.edu/agronomynews/
Hart, A. 2017. What’s really the point of wasps? BBC News. Available www.bbc.com/news/science-environment
Swanson, C. 2016. Figuring Out Figs. Science World. Available www.scienceworld.ca/stories/figuring-out-figs