Wasps, members of the insect order Hymenoptera, are a vast and ecologically diverse group that includes both solitary and social species. Although often viewed as pests, many species play roles in plant pollination and pest control. Understanding which floral characteristics appeal to them provides insight into their foraging behavior. This article identifies the specific visual, olfactory, and structural features of flowers that consistently draw wasps.
Why Wasps Seek Out Flowering Plants
Wasps visit flowers for two distinct biological reasons, reflecting a seasonal shift in their nutritional needs. The primary motivation for adult wasps is to acquire carbohydrates in the form of nectar, which provides the high-energy fuel required for flight and daily activity. Nectar serves as the primary energy source for both solitary and foraging social wasps.
The second reason flowers attract wasps is their function as a hunting ground. Social species, like yellow jackets, require a protein-rich diet to feed their developing larvae. Flowers that attract numerous small insects, such as flies and aphids, become ideal foraging locations where adult wasps can capture prey. This protein collection is intense during the spring and early summer when the colony is rapidly expanding.
As summer progresses into autumn, the number of larvae needing protein declines, causing a dietary shift in social wasps toward pure sugar. This late-season change explains why wasps become more noticeable around human food sources and focus almost exclusively on nectar-rich flowers. This requirement for sugar ensures the survival of future queens and males.
Visual and Scent Cues
A wasp’s search for a flower is guided by a combination of visual and chemical signals. Unlike bees, which often favor deep blues and purples, wasps are attracted to flowers displaying bright, accessible colors. They respond strongly to white, yellow, and certain green hues, which stand out against the background foliage.
While visual appearance is helpful, scent is often the most significant factor in a wasp’s ability to locate a suitable plant. Wasps possess a keen sense of smell and can learn to associate specific floral odors with a sweet reward. A flower’s olfactory bouquet can be overwhelmingly attractive, even when the visual cues are weak or cryptically colored.
The chemical signals that draw wasps are not always pleasantly sweet, as some plants attract them by mimicking other sources. Certain wasp-pollinated flowers emit odors that resemble decaying matter or pheromones released by other insects. This strategy draws in predatory wasps looking for a sugar source or a concentrated area of potential prey.
Specific Plant Families That Attract Wasps
The physical structure of a flower is often a strong determinant of its appeal to wasps, particularly those with short mouthparts. Plants from the Umbelliferae family (Apiaceae) are among the most visited by various wasp species. Their characteristic flower heads, called umbels, are flat, umbrella-like clusters composed of many tiny, easily accessible flowers.
This open structure acts as an ideal landing platform for larger predatory wasps, allowing them to easily access exposed nectaries or ambush small feeding insects. Specific Umbellifers that are highly attractive include Wild Parsnip, Fennel, Dill, and Queen Anne’s Lace. These plants are important for parasitic wasps, which are often too small to navigate more complicated flower shapes.
Another frequently visited family is the Mint family (Lamiaceae), which includes plants like Bee Balm, Catmint, and various types of Mint. These plants often produce abundant, nectar-rich flowers with readily accessible shapes. Their strong, aromatic foliage, while sometimes thought to be a deterrent, does not repel wasps from the sweet floral reward.
Plants with shallow, open blossoms that concentrate nectar are favored because they accommodate the wasp’s foraging style. The accessibility of the reward, combined with a strong olfactory signal, explains why generalist flowers—those not specialized for a single type of pollinator—are commonly found on a wasp’s foraging route. This preference ensures wasps can efficiently refuel or hunt without manipulating complicated floral mechanisms.