Neopasites fulviventris

Differs from other Neopasites species by the tawny or yellowish-brown ventral abdominal coloration referenced in its specific epithet. Separation from the more widespread N. macropis requires careful examination of antennal proportions and clypeal shape. Males may be distinguished by genitalic characters. Specimens should be compared with type material or authoritative determinations for reliable identification.

Found in habitats supporting its presumed host bees. Based on related species and tribe characteristics, likely associated with open habitats including prairies, meadows, and sandy areas where host nesting occurs.

North America. Records indicate presence across parts of the United States and possibly southern Canada, though precise range boundaries require verification.

Adult activity period corresponds with flight times of host species. Based on related nomadine bees, likely active from late spring through summer (May–August), with peak activity varying by latitude.

• Macropis - presumed hostOther Neopasites species are known cleptoparasites of Macropis (Melittidae), which are oil-collecting bees. This host association is inferred from genus-level biology but has not been confirmed for N. fulviventris specifically.

As a cleptoparasitic bee, females do not construct nests or collect provisions. Eggs are laid in host nests, typically during or after host provisioning. Larvae consume host provisions and typically kill the host egg or larva. Developmental stages follow the typical holometabolous pattern of bees, with detailed timing unknown for this species.

Females are presumed to locate host nests by olfactory cues associated with host-collected floral oils (macrocarpolides). Males may exhibit territorial behavior near host nesting aggregations. Both sexes visit flowers for nectar, though they do not collect pollen.

Acts as a brood parasite (kleptoparasite) on other bee species, potentially influencing host population dynamics. Its presence indicates established populations of host bees and functional oil-producing plant-host bee-parasitoid food webs.

No direct economic importance. Of interest to bee systematists and conservation biologists monitoring native bee diversity. Indirectly indicates ecosystem health through its dependence on intact host bee populations and oil-producing host plants.

• Neopasites macropisMost similar congener, differing in details of antennal proportions and coloration pattern; N. fulviventris has more extensively tawny ventral abdomen.
• EpeolusOther nomadine cleptoparasitic bees with similar general appearance, but Epeolus species typically parasitize Colletidae rather than Melittidae and have different thoracic punctuation patterns.
• TriepeolusAnother nomadine genus with similar size and coloration; distinguished by differences in facial structure and male genitalia.

• cleptoparasite
• cuckoo bee
• Nomadinae
• Biastini
• native bee
• North America

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