CUCKOO LEAFCUTTER BEES

Genus Coelioxys  

Coelioxys cuckoo bees prey on leafcutter bees by invading their nests and depositing eggs in them.  When the cuckoo's young hatch, they eat the host's eggs and then devour the stores of nectar and pollen left by the mother leafcutter for her offspring.  

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Coelioxys cuckoo bees are members of the same tribe as leafcutter bees -- Megachilini -- and somewhat resemble them.  Cuckoo leafcutters, however, lack pollen-collecting scopal hairs, because they do not collect pollen.  They don't have to, since they acquire it by robbing it from their hosts.  (Cuckoos, nonetheless, do drink nectar from flowers.)

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In addition, as shown at right, the abdomen of the female cuckoo leafcutter terminates in a sharp spade-like tip -- the Greek Coelioxys means "sharp belly".  This feature allows the cuckoos to break through the brood-cell walls that leafcutters construct with leaves, petals and other materials.  Male cuckoo leafcutters have abdomens armed with multi-pronged tips.   

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Cuckoo leafcutters sometimes can be seen lifting their pointed, conical abdomens, in a scorpion-like manner.  Both males and females also have a habit of grasping leaves and stems with their jaws.  Male cuckoo leafcutters can be found sleeping on vegetation, hanging upside-up or upside down by their mandibles. 

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According to entomologist Charles D. Michener, members of the genus Coelioxys share the distinctive trait of having hairs on their eyes.  In addition, the wings of the cuckoo leafcutter bee have only two submarginal cells, and the back rim of the bee's scutellum (at the hind end of the thorax) is often toothed.  These traits are shown in the photo strip below right.
 

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General Identification Information: 

Cuckoo leafcutter species appear very similar to the casual observer, and species identification is often best left to an expert.  Cuckoo leafcutter species are told apart by such traits as leg color; the patterns of pale hair bands and grooves on the abdomen; the form of the abdominal tip; and the shape of the bottom edge of the cuckoo's thorax (the scutellum).  Coelioxys cuckoos have foveae (depressions) on the sides of their second or third abdominal segments (T2 and T3). Noting the size, shape and presence or absence of such foveae often aids in species identification.

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Coelioxys cuckoo bees frequently have black bodies and legs.  Some species found as far north as New York have red legs and tegulae (the nodes where the wings join the bee's body).  Neotropical species, such as those found in the Lower Rio Grande Valley and in Mexico, tend to be more colorful.  In addition to having red legs and tegulae, they may have striking red patterns on their abdomens and thoraxes.  

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Coelioxys bees of the National Butterfly Center:

During the autumn of 2018 and 2019, four Coelioxys species were discovered at the National Butterfly Center:  the Aztec cuckoo leafcutter (Coelioxys azteca);  Slosson's sand-dwelling cuckoo leafcutter (Coelioxys slossoni arenicola); the Texas cuckoo leafcutter (Coelioxys texanus) and the scaly cuckoo leafcutter (Coelioxys edita).  All four of these are striking bees with extensive red coloration on their abdomens and other body parts. 

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The Aztec cuckoo leafcutter is rarely seen in the United States.  It is a neotropical species that has been documented principally in Mexico. 

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Slosson's sand-dwelling cuckoo leafcutter is native to Mexico and border areas of the United States.  Coelioxys edita is a more widespread species, found throughout the western United States, as far east as Illinois, Arkansas and Florida, and as far north as Alberta.

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All of these species are shown in detail in the entries below.

A female Coelioxys slossoni arenicola cuckoo leafcutter bee

The red underside of a female  Slosson's sand-dwelling cuckoo leafcutter bee

Traits of Coelioyxs cuckoo bees

TAXONOMY OF CUCKOO LEAFCUTTER BEES

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Order:   Hymenoptera

Family:   Megachilidae

Subfamily:   Megachilinae

Tribe:  Megachilini

Genus:   Megachile

Species shown on this page:  

    Coelioxys (Leuraspidia) azteca (Aztec cuckoo leafcutter) a
    Coelioxys (Neocoelioxys) slossoni arenicola 
        (Slosson's sand-dwelling cuckoo leafcutter)

  Coelioxys (Synocoelioxys) texanus
        (Texas cuckoo leafcutter)

  Coelioxys (Xerocoelioxys) edita

        (Scaly cuckoo leafcutter)

REFERENCES

GUIDE INDEX

INFORMATION
ON THIS GUIDE

ID GUIDE TO WILD BEES
OF THE NATIONAL BUTTERFLY CENTER
Mission, Texas

CUCKOO-LEAFCUTTER BEES
Coelioxys