Coelioxys alternatus

Say, 1837

Alternate Cuckoo Leafcutter Bee

Coelioxys alternatus is a North American of cuckoo leafcutter bee in the Megachilidae. As a kleptoparasite, females do not construct their own nests but instead lay in the nests of leafcutter bees (Megachile species). The developing larva kills the host egg or larva and consumes the pollen provisions stored by the host female. The species is recorded from Vermont and other parts of eastern North America.

Pronunciation

How to pronounce Coelioxys alternatus: /siːliˈɒksɪs æltərˈneɪtəs/

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Identification

Coelioxys are distinguished from their Megachile by their slender, -like body shape and pointed . Males have distinctive modified abdominal segments. Identification to species level within Coelioxys requires examination of specific morphological characters including abdominal punctation and spine structure; C. alternatus is one of several similar species in eastern North America.

Habitat

Found in areas where leafcutter bees (Megachile ) nest, including gardens, meadows, and open with suitable nesting substrates for hosts. Hosts typically nest in pre-existing cavities such as hollow stems, borings in wood, or artificial hotels.

Distribution

Recorded from eastern North America; confirmed present in Vermont, United States. The broader range likely extends through the northeastern and possibly north-central United States based on related distributions, though specific records are limited.

Host Associations

Megachile - kleptoparasiteFemales deposit in nest ; larvae kill host egg/larva and consume host's pollen provisions

Behavior

Females locate active Megachile nests and, when the female is absent, enter to deposit their own between the leaf fragments lining the . The parasitic larva develops rapidly, eliminating the host offspring. Males are often observed patrolling flowers, particularly those visited by host females.

Ecological Role

Acts as a regulator of leafcutter bee populations. As a kleptoparasite, it represents a natural component of native dynamics and contributes to biodiversity in .

Human Relevance

May be encountered by observers monitoring artificial hotels or gardens with leafcutter bee activity. Its presence indicates a functioning, diverse native bee . No direct economic impact; not a pest .

Similar Taxa

NomadaAlso kleptoparasitic bees with -like appearance, but Nomada parasitize mining bees (Andrenidae) rather than leafcutter bees, and have different abdominal structure
SphecodesBlood bees are kleptoparasites of sweat bees (Halictidae), typically smaller and with reddish coloration not seen in Coelioxys
Megachile ; Coelioxys can be distinguished by more slender body, pointed , and lack of pollen-carrying scopa on underside of abdomen

More Details

Conservation note

The presence of Coelioxys in an area indicates healthy of leafcutter bees. Conservation efforts targeting leafcutter bees, such as providing diverse cavity-nesting substrates and maintaining floral resources, indirectly benefit these .