The Master Gardener’s Bookshelf
Wasps: Their Biology, Diversity, and Role as Beneficial Insects and Pollinators of Native Plants
by Heather Holm
Review by Susan Wilhelm, Extension Master Gardener
When thinking about attracting pollinators to the garden, wasps may not be the first insect that comes to mind. However, wasps are important contributors to garden ecology – as pollinators, or incidental pollinators, of native plants, and as beneficial insects preying on other insects that damage crops and plants. Wasps: Their Biology, Diversity, and Role as Beneficial Insects and Pollinators of Native Plants by Heather Holm, provides a detailed look at these intriguing insects. It is a fascinating read and one that will give you a new appreciation for wasps of all kinds and the vital role they play in promoting healthy garden ecosystems.
Holm is a biologist, popular author, and pollinator advocate. In Wasps, she focuses on “the most common flower-visiting wasps in eastern North America,” those one might “find in their garden, nearby park, natural area or nature preserve.” Holm acknowledges that “[m]any people have an aversion to wasps because they hold an unpleasant memory by being stung by one,” but the reality is that “the vast majority of wasp species do not nest socially and, therefore, have very few or no negative interactions with humans.”
The book begins with basic information. This includes wasp anatomy, how they live (social vs solitary), their life cycles, nesting habits (above or below ground, or no nest at all) and construction, and what they eat. She also answers questions such as when do wasps use their stingers, where do wasps spend the night, and why do some wasps hang around soft drinks at a picnic?
Holm also explains the ecosystem services wasps provide that directly or indirectly benefit humans. Wasps are not pollinator superheroes like bees, but certain wasps make up a significant portion of flower-visiting insects and these visits can result in pollination. Additionally, “wasps are predators and parasitoids of other insects and spiders that in many instances cause damage to plant roots, foliage, fruit, or seed, including food crops and nursery plants.” For example, Polistes metricus (metric paper wasp) eat cabbage looper caterpillars and Astata unicolor (monochromatic square-headed wasp) eat brown marmorated stink bugs.
A substantial portion of the book is wasp profiles organized by family, and within family, by genus. Each profile has one to three photographs, noting one or more of the wasp’s diagnostic characteristics (though Holm points out that many wasp species cannot be identified from a photograph), along with written descriptions of some of the profiled wasp’s diagnostic features, a short summary of what is known and documented about the wasps’ nesting biology and their prey, and a range map (using the best available information) indicating where the wasp has been documented or well-documented. The profiles also list the native nectar plants the wasp visits and other information such as the time of the year the adults are active, the size of the wasps, or the nest cavity diameter range.
This is followed by regional planting guides identifying native plants that attract different wasps. The regional planting guide for the mid-Atlantic states include several of the Master Gardener of Northern Virginia’s Tried and True Native Plant Selections such as Pycnanthemum muticum (short-toothed/clustered mountain-mint).
Wasps is filled with outstanding photographs and helpful summary tables. For instance, one table lists wasps by genus and the plants with which they interact. Additionally, sprinkled throughout, are wonderful quotes from wasp researchers who worked in the late 1800s and early 1900s reminding us that humans have long been interested in wasps and their role in the natural world. It would be a good reference book for any mid-Atlantic garden library.
Wasps: Their Biology, Diversity, and Role as Beneficial Insects and Pollinators of Native Plants by Heather Holm (Pollinator Press LLC, 2021) is available at national booksellers.