Wasps are a diverse group of insects. Often perceived solely as aggressive pests, these creatures play varied roles within ecosystems. While many people associate wasps with stings, their relationship with the plant world, particularly flowers, is often unnoticed. Understanding why wasps visit flowers reveals their ecological contributions, including their function as garden pollinators.
What Attracts Wasps to Flowers
Wasps visit flowers primarily to fulfill their dietary requirements, which differ between adult wasps and their developing offspring. Adult wasps largely subsist on sugary substances, seeking out nectar from flowers, honeydew produced by aphids, or even fruit juices for immediate energy.
In contrast, wasp larvae require protein for their growth and development. Adult social wasps, such as yellow jackets and paper wasps, hunt other insects like flies, caterpillars, and aphids, chewing them into a pulp to feed their young. Flowers can serve as hunting grounds where adult wasps find these smaller insects that are also drawn to the blooms.
This dual foraging strategy means wasps are often found around flowers for both their own sustenance and to gather prey for the next generation. The specific dietary needs of a wasp colony shift throughout the season. In early to mid-summer, when larvae are actively developing, adult wasps prioritize collecting protein-rich prey.
As the summer progresses and fewer larvae require feeding, the adult wasps’ demand for sugar increases, leading them to seek out more nectar and other sweet sources. This seasonal change explains why wasps might seem more interested in sugary human foods later in the year.
Wasps’ Role in Pollination
Wasps transfer pollen between flowers, contributing to pollination, although their efficiency varies greatly by species. Unlike bees, which have hairy bodies and specialized pollen-carrying structures, most wasps have smoother bodies with less hair, meaning pollen adheres to them less effectively. They are generally less efficient at widespread pollen transfer than bees.
Despite this, wasps inadvertently move pollen as they travel from flower to flower in search of nectar or prey. Their visits still contribute to plant reproduction, and in some specific cases, certain wasp species are highly specialized pollinators. Fig wasps, for example, are the sole pollinators for hundreds of fig species, demonstrating a symbiotic relationship.
Additionally, some orchid species rely entirely on specific wasps for pollination, attracting them with scents mimicking female wasps to ensure pollen transfer. There are also “pollen wasps” (Masaridae family), which, unlike most wasps, are vegetarian and actively collect pollen and nectar for their larvae, behaving similarly to bees. These specialized wasps play an important function in maintaining ecological diversity for the plants they pollinate.
Flowers That Attract Wasps
Wasps are drawn to flowers that offer easily accessible nectar, often characterized by their structure and color. Flowers that are shallow and open allow wasps to readily access the sugary liquid with their relatively short mouthparts.
The color of flowers also plays a part in attracting wasps. They are often drawn to blooms in shades of yellow, white, blue, and purple. Some plants in the Myrtaceae family, such as Eucalyptus and Leptospermum, are frequently visited by flower wasps for nectar. The waterleaf family, including plants like Phacelia and Eriodictyon, is another group preferred by certain pollen wasps.
The scent of a flower can also be a significant attractant for wasps, particularly for species involved in specialized pollination syndromes, like those with orchids. These floral characteristics provide clear signals to foraging wasps, guiding them to reliable sources of energy.
Coexisting with Wasps in Your Garden
Understanding wasp behavior can promote a more harmonious relationship with them. Wasps are generally not aggressive unless they feel provoked or are defending their nest. Rapid movements or attempts to swat them can be perceived as threats, leading to a defensive response.
Recognizing their beneficial roles, wasps are effective predators of many garden pests, including aphids and caterpillars, which helps maintain plant health. To minimize unwanted interactions, gardeners can avoid leaving sugary drinks or exposed food unattended, especially in late summer when wasps are more focused on carbohydrate sources.
Identifying the type of wasp can also be helpful; solitary wasps, which do not form colonies, are far less likely to sting humans compared to social wasps. If a social wasp nest is located in a high-traffic area, observing it from a distance and understanding their seasonal activity patterns can inform decisions about management.