Two-spotted Bumble Bee, Bombus bimaculatus

Excerpted from Bumble Bees of Wisconsin

Two-spotted Bumble Bee, Bombus bimaculatus Bombus bimaculatus populations are also stable. Queens of this species are the first to emerge in the Spring, and can be found foraging on woodland ephemerals like Dutchman’s Breeches.

Physical Description

Body hair long and uneven. Thorax mostly yellow, with a circular patch of all black hairs between the base of the wings. First abdominal segment fully yellow, with a “W” or two-spotted yellow patch of hair in the middle of the second abdominal segment. While generally similar to workers and queens, males have variable and sometimes non-symmetrical coloration patterns. Males typically with some yellow hairs on the front of the face. Males also lack corbiculae, or the flattened midleg of the hind leg used for transporting pollen.

Activity Period

Two-spotted Bumble Bee activity period Bombus bimaculatus has a shorter colony cycle, with peak worker numbers in the end of June and early July. Queens are first to emerge after warm weather has returned (concurrent emergence with spring ephemerals). New queens and drones can be found from early July to August.

Range

Two-spotted Bumble Bee, Bombus bimaculatus graphic Generally south of the tension line (Wausau/Stevens Point and farther south). However, this species appears to be expanding its range and does well in the agricultural areas of the state.

Preferred Flowers

 Thistle
 St. John’s Wort
 Sweet Clover

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