Wasps Biosurveillance & Milkweed Haven

Nature Highlights

Season: Summer | Location: New-England’s meadows, parks, and gardens

Look for wasps and the intense activity of insects on milkweeds in the warm summer months. What do they have in common? Both have a bad ‘rep’– yet they are ecologically critical, truly endearing, and certainly not to be feared nor despised. Here’s to these incredibly important species!

EwA runs biodiversity walks monthly when we invite our guests to observe with us the passage of the seasons on the local flora and fauna. Each exploration is a chance to highlight nature chronicles that we may enjoy together right at the time of the walk. 📅   Check EwA’s events calendar and come discover with us the hidden stories of our urban green spaces.


Mid-summer is a time of the year when wasps are out and about. Many people fear them, although there’s no good reason to be afraid. They won’t mind having you around unless they feel threatened by you. Be slow and mindful in the field and marvel at their beauty. 

Wasps are important insects. They are incidental pollinators. Like all pollinating insects, they play a crucial role in the development of the fruits and vegetables we consume every day. In addition, they feed on insects that transmit diseases that are harmful to both plants and humans. To be more precise, adult wasps feed mainly on sugar (nectar, fruits, etc…).

EAB | © Joe MacIndewar

It is their larvae that feed on “flesh”. They eat the insects (their version of steak) that the workers bring them: flies, caterpillars, aphids, worms, scale insects, and more. They get rid of many pests for the gardener.

We’re most familiar with the social yellow jackets and paper wasps who live in colonies, but most wasps are actually solitary. 

Cerceris fumipennis is one of those solitary wasps. It is rather small and it nests in a tunnel that it excavates in hard-packed sand soil and consists of 5-24 chambers or cells. The entrance of the nest is a hole at the top of the mound of sand that is the width of a pencil diameter. These chambers will be filled with food to feed her progeny. This little wasp is instrumental in bio-surveillance. It feeds on the beetles of the Buprestid family, which the emerald ash borer (EAB) is a member of–an invasive species that is decimated our ash tree species throughout America.


Be on the lookout for milkweed plants. Milkweeds are perennials with flowers arranged in umbels. They are called milkweed because of the whitish latex that drains when the plant is damaged.

The nectar of milkweed flowers attracts many pollinating insects and birds such as bees, wasps, butterflies, beetles, flies, and hummingbirds. Several insects feed, at one stage or another, exclusively on milkweeds. This is the case with the monarch caterpillar. The adults must lay their eggs directly on these plants in order to provide the young caterpillars with the food they need. This is why the survival of the monarch butterfly is intimately linked to milkweeds.

Climate change is being felt throughout the migrating territory of the monarchs, especially on the wintering sites in Mexico, strongly affecting the populations of this butterfly. Even so, the loss of natural habitats and the eradication of milkweed by pesticides in agricultural areas are the main causes of the decline of monarchs. Despite the importance of native milkweeds to pollinators and monarchs, these plants are often seen as weeds and are eradicated from fields and roadsides.

Help pollinators by planting milkweed and observing it throughout the summer–you won’t be disappointed!


Enjoy your time outside exploring Nature’s wonders right in our yards, parks, and urban forests. 📅 Join our Biodiversity Walks. Share your findings with us (you can comment below)!


EwA Useful Links

🌿 EwA Field Highligths » Wasps & Biosurveillance–Milkweed Pollinator Haven (pdf)

📸 EwA New England July & August Biodiversity Sightings through Time

📖 Pollinators of Native Plants: Attract, Observe and Identify Pollinators and Beneficial Insects with Native Plants (2014) by Heather N. Holm

📖 The Book of Swamp & Bog: Trees, Shrubs, and Wildflowers of Eastern Freshwater Wetlands (1995) by John Eastman  (Author), Amelia Hansen (Illustrator)


by Claire O’Neill I August, 6th 2021 

The photos in this article are visual records that the EwA team has collected in the Greater Boston Area. Click on any picture, and you’ll land on the record and its owner (the records shown in this article are from EwA participatory scientists Claire O’Neill, Daniel Onea, and Joe MacIndewar). Photos are licensed under Attribution-NonCommercial (CC BY-NC). 

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