Rusty Patched Bumble Bee

The Rusty Patched Bumbleebee

Scientific name: Bombus affinis

Named for the rusty orange patch on its abdomen, the rusty patched bumblebee is on the federal endangered species list and a species of special concern in Connecticut.  The rusty patched bumblebee was last detected in Connecticut in 1997.  B. affinis is a highly social insect living in a hive consisting of one queen, many female worker bees, and drone bees (male bees) during certain times of the year.  This species is known for having one of the largest bumblebee colonies, sometimes over 1000 bees in one hive.  B. affinis is normally one of the first bees to emerge in the spring and the last to go into hibernation for the winter and is a generalist feeder visiting many different wildflower species and a known pollinator of many different crops.  Hives are normally found in the ecotone (transition between meadows and forests).

Over the past couple of decades, the historic range of the rusty patched bumblebee has declined upwards of 90%.  This is hypothesized to be due to numerous reasons/ challenges facing many of our pollinators.  First, the commercialization of bumblebees for pollinating, especially in greenhouses has brought about an increased risk of pathogens and disease to native populations.  Habitat change, degradation, and climate change have led to a lack of available food sources in areas during certain times of the year. Even though B. affinis is a generalist early in the season, and during certain times of the year, food sources in different areas are minimal, if one source of food is eliminated that was once available during these scarce times it could be very detrimental.  The last cause of population decrease is the use of pesticides.  The use of herbicides to reduce sources of food in people’s lawns along with the increased use of general insecticides have most likely led to reduced population size.  In New England, the rusty patched bumble bee decline has led to a possible decline in crops that were once important pollinators for apples, cranberries, plums, and alfalfa.

The Granby wildflower meadow could possibly serve as a harborage for the rusty patched bumblebee.  The diverse selection of wildflowers should provide a continuous source of food during the whole year while also having that needed ecotone for possible hive locations on 3 sides of the field.