Some species of bees are specialists -- that is, they feed on a single plant or group of related plants.  Among these is the wild squash bee (Peponapis pruinosa).  

    Squash bees evolved in tandem with squash plants, which  are native to the Americas.  These wild bees feed solely on cucurbits, that is, squashes, pumpkins, gourds and melons.  The bees’ geographical range coincides precisely with the range of such plants.   

    Squash bees are unusual because of their ability to fly through the dark in order to arrive on host plants before sunrise.  A squash bee’s ocelli -- its three small eyes located between its two larger main eyes – are enlarged for this purpose.  The bees begin their daily feeding early because squash flowers tend to wilt by mid-afternoon.

    These bees are exceptional pollinators.  Although honey bees sometimes feed on the nectar of squash blossoms, squash bees are such efficient pollinators that they generally succeed in pollinating all of a squash plant’s blossoms before honey bees brought in as crop pollinators reach the flowers.

    Squash bees have clownish faces and are often described as having “big noses”.   If you peel back the petals of a squash flower, you are likely to find one of these bees gazing up at you.  In the afternoon, it is not unusual to see several squash bees, their work done, sleeping together inside a wilted squash blossom.