Pruinose Squash Bee Mission Update

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September 30, 2020 by Julia Pupko

Earlier this year, we called on our community scientists to keep an INaturalist eye out for the Pruinose Squash Bee (Peponapis pruinosa), also known as the Eastern Cucurbit Bee. This small insect is just under 1.5 cm at maximum (smaller than the diameter of a dime), yet is an important pollinator for all of the plants in the cucurbit family (squash, cucumber, watermelon, pumpkins, and others).The Pruinose Squash Bees entire life cycle revolves around squash flowers–collecting pollen in the morning when the flowers are open, then building underground nests nearby (females) or resting within the flowers (males) once the flowers close in the afternoon.

The map on the left is of Pruinose Squash Bee observations from 2020, and the map on the right is of Pruinose Squash Bee observations in all years prior to 2020. Click the map to view the live map on INaturalist.

According to our Vermont Wild Bee Survey, there were surprisingly few records of this bee reported from across Vermont. We wanted to know how wide-spread these amazing native pollinators are in the state, so we called on our community scientists (that is all of you!) to help us find out.

Over the course of the summer, there were nine observations of the Pruinose Squash Bee across Vermont. Most of these observations spanned the upper third of Vermont (Montpelier area north), with no observations between Royalton and Montpelier, and only three observations south of Royalton (see map provided). Prior to 2020, there were only 18 observations of the Pruinose Squash Bee, most of which were in the greater Burlington area or along the southeastern border between Vermont and New Hampshire (see map provided). As you can see, 2020 surveys expanded the known range of the Pruinose Squash Bee in Vermont. However, the Northeast Kingdom and the western portions of central and southern Vermont are all lacking observations – is this because the bee does not exist in these locations or do we just not have enough surveys? Let’s find out together next year when they are once again buzzing around our gardens.