Melissodes desponsus

Smith, 1854

Eastern Thistle Longhorn Bee

Melissodes desponsus is a solitary, ground-nesting longhorn native to northeastern North America. Females are oligolectic on Cirsium thistles, collecting white pollen that often obscures their distinctive orange scopae. The is active in mid-to-late summer and has been assessed as vulnerable or imperiled in several regional conservation evaluations, though it lacks a comprehensive rangewide status assessment.

Melissodes desponsus by (c) Amy Schnebelin, some rights reserved (CC BY), uploaded by Amy Schnebelin. Used under a CC-BY license.

Melissodes desponsus by (c) Ben Babcock, some rights reserved (CC BY), uploaded by Ben Babcock. Used under a CC-BY license.

Triepeolus donatus, m, face, Centre Co, PA 2016-12-22-13.12 (31880758773) by USGS Bee Inventory and Monitoring Lab from Beltsville, Maryland, USA. Used under a Public domain license.

Pronunciation

How to pronounce Melissodes desponsus: /mɛˈlɪsoʊdiːz dɛsˈpɒnsəs/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from other Melissodes by the combination of orange scopae in females (often hidden under white pollen), pale yellow , and strict association with Cirsium thistles. Males identified by yellow and long . May be confused with other Eucerini, but the specific plant association and northeastern distribution help separate it from western like M. agilis or M. robustior.

Images

Appearance

Medium-sized with pale yellow and black . Females measure 12–13.5 mm and possess orange scopae on the hind legs, frequently coated with white Cirsium pollen. Males measure 11–13.5 mm, have longer (the 'longhorn' trait characteristic of the ), and display yellow . Both sexes show the typical Melissodes body plan with robust hind legs in females for pollen transport.

Habitat

Open supporting Cirsium thistles, including meadows, fields, and disturbed areas. Requires bare or sparsely vegetated ground for nesting.

Distribution

Northeastern quadrant of the United States, extending into southern Canada. Records from Vermont and broader northeastern North America.

Seasonality

Active mid-to-late summer.

Diet

Females are oligolectic on Cirsium thistles. Nectar sources presumably include Cirsium and possibly other flowers, though specific documentation is limited.

Host Associations

Cirsium - pollen source plant; females collect white pollen that often covers the orange scopae

Life Cycle

Ground-nesting solitary . Females excavate individual burrows, sometimes clustered, with entrance holes approximately pencil-diameter or smaller, often with small soil mounds. Males do not participate in nest construction.

Behavior

Males have been observed in sleeping on vegetation in related Melissodes , though specific documentation for M. desponsus is not confirmed. Females are active foragers on thistles during daylight hours.

Ecological Role

of Cirsium thistles. Contributes to thistle and serves as a food source for and in native .

Human Relevance

Contributes to pollination of native thistles; potential for health in northeastern meadows. No documented economic importance or negative impacts.

Similar Taxa

Melissodes agilisWestern with similar male sleeping and territorial , but occurs in different geographic range (western North America) and has different associations
Melissodes robustiorSimilar size and , but distinguished by distribution and subtle morphological differences; may require examination of male genitalia or specific scopal coloration
Svastra obliquaRelated Eucerini that shares longhorn and male roosting , but belongs to different with distinct facial markings and preferences

More Details

Taxonomic history

Originally described with sexually dimorphic : females as Melissodes desponsa and males as M. nigripes by Frederick Smith in 1854. Later synonymized under M. desponsus.

Conservation status

Listed as vulnerable or imperiled by several regional sources, though no comprehensive IUCN or federal assessment exists. Status reflects loss and potential declines in native thistle .

Nesting biology

Nests are individual burrows dug by females in the ground, with entrance holes about pencil-diameter or slightly smaller, sometimes with small soil piles resembling 'mini-volcanoes.' Nest patterns vary from widely separated to clustered depending on local soil conditions.