Proximity of longhorn bees, Melissodes bimaculatus to cuckoo bees, Triepeolus sp. (some of which were identified as Triepeolus lunatus) during summer 2023 on a tallgrass prairie remnant, Racine Co., WI.

Larva of cuckoo bees, Triepeolus lunatus, are cleptoparasitic on Melissodes bimaculatus. In 2023, I made numerous trips to Barnes prairie and observed both species, which were found in close proximity to each other. Some of my observations are summarized below.

During late spring and summer, a number of Melissodes sp. (many identified as M. bimaculatus, two spotted longhorn bees), were observed on a section of Barnes Prairie in Racine County, WI, which was about 2,500 square feet in area. The site was located on a slight slope, with grasses and over 40 species of native and non-native forbs. A hedgerow to the south held the remains of a decaying woodpile.

During the day, bees were seen foraging on the following flowers:
June: Carolina rose, woodland poppy, purple clover, wild geranium
July: Wild bergamot, motherwort, bidens, lance-leaf coreopsis, thistle, common milkweed
August: Purple coneflower, black-eyed Susan, brown-eyed Susan, vervain, chicory, sunflowers

Counts were taken early morning, after sunrise, or early evening, before sunset, of male longhorn bees resting on grass leaves, aster leaves and stems, and goldenrod leaves and stems within an 18 square foot area. The plants that the bees rested on changed every few days, but stayed within this area for the entire time they were observed.

Date, No of longhorn bees counted
July 6, 2023, 14
July 7, 2023, 4
July 10, 2023, 14
July 11, 2023, 14
July 12, 2023, 11
July 13, 2023, 9
July 15, 2023, 9
July 16, 2023, 9
July 19, 2023, 6
July 20, 2023, 14
July 22, 2023, 8
July 27, 2023, 9

In addition to these bees, solitary longhorn bees were also found in early evening on grass or aster plants about one foot from an area where there were several resting cuckoo bees, Triepeolus sp. (several identified as T. lunatus).

Date, Number of longhorn bees found near cuckoo bees
July 27, 1
Aug. 6, 1

An apparent Melissodes bimaculatus, longhorn bee, nest location was found by the hedgerow, near a rotting woodpile. One bee was seen entering a hole in the ground on July 18. On July 27, late afternoon, a longhorn bee was seen going into this hole. Stems of a gray dogwood shrub were approximately two feet from the hole. This presumed nest was approximately 15 feet from the area where cuckoo bees were seen resting in early morning and late afternoon, and about 50 feet from the resting male longhorn bees.

Resting cuckoo bees, Triepeolus sp. (Triepeolus lunatus), were counted and photographed in early morning, after sunrise, or late afternoon, before sunset. Bees were resting on stems of native and non- native grasses, on annual non native plants, and on aster leaves and stems. The bees relocated to different plants of the same species every few days, but stayed within a several square foot area for the entire time they were observed. These resting bees were located approximately 35 feet from the resting longhorn bees.

Date, No of cuckoo bees counted
July 7, 2023, 1
July 18, 2023, 4
July 19,2023, 4
July 20, 2023, 4
July 22, 2023, 2
July 27, 2023, 3
Aug. 6, 2023, 3

In addition to these sightings, there were two instances in the early evening where resting cuckoo bees were found on aster stems or leaves, located approximately two feet from the groups of resting longhorn bees.

Date, No of cuckoo bees near longhorn bees
July 19, 2023, 1
July 27, 2023, 1

During the day, cuckoo bees were seen foraging on several flower species:
July: Lance-leaf coreopsis, black-eyed Susan, alsike or hybrid clover.

No cuckoo bees were seen entering the hole the longhorn bees had entered by the hedgerow. The hybrid clover cuckoo bees frequented was located several feet from the presumed longhorn bee nest.

Publicado el 15 de noviembre de 2023 por bkis