Genus: Hoplostelis Dominique, 1898
Subgenera: Hoplostelis, Rhynostelis
Common name: none
Hoplostelis are robust parasitic bees that lack scopae (Michener 2007). They range in body length from 8–14 mm, they have black or dark brown integument with yellow abdominal bands and patterning on the head and thorax that may be red or orange in some species. The markings in some species can be extensive, making them primarily yellow (Michener 2007).
(modified from Michener 2007 unless otherwise stated)
Hoplostelis most closely resembles Austrostelis because both genera are cleptoparasitic and possess one protibial and mesotibial apical spine (Michener 2007). Austrostelis females can be differentiated by the lack of a distinct protuberance at the base of the mandible (Michener 2007).
There are no known invasives.
Hoplostelis females are cleptoparasitic and do not gather pollen, but are presumed to use nectar from a variety of flowers (Michener 2007). Hoplostelis parasitize Euglossini (Apidae) (Michener 2007). Hoplostelis multiplicata, the only species of the Rhynostelis subgenus, parasitizes Eufriesea (Moure and Urban 1994; Urban and Parizotto 2012). Hoplostelis cordata is known to parasitize Euglossa cordata and E. variabilis (Bennett 1966; Augusto and Garófalo 1998).
Female Hoplostelis are cleptoparasitic. Hoplostelis bilineolata parasitizes Euglossa spp., which may be communal or primitively eusocial. The presence of multiple host females in Euglossa cordata nests does not seem to be a deterrent to H. bilineolata parasitism; the hosts do not attempt to guard the cells (Rozen 1966; Augusto and Garófalo 1998). However, in E. viridissima, communal nests show lower rates of H. bivittata parasitism (Cocom Pech et al. 2008). Once a host nest is found, the female parasite chases off the host female(s) through aggressive hazing and biting. This can potentially lead to the host’s death. After the host female has been eradicated, the Hoplostelis female uses resin from around the nest to seal herself inside (Cocom Pech et al. 2008). The Euglossa young within their pot-shaped cells are destroyed one at a time. Eggs are either eaten or removed from the resin-based cells once opened by Hoplostelis; larvae are also removed from opened cells, stung, bit, and killed, sometimes being coated over with resin afterwards (Bennett 1966). If these cells are adequate for parasitism, an egg is placed in the cell, and it is resealed (Bennett 1966). If a cell containing an unemerged adult is found, the cell is crushed with the mandibles dispatching the host inside (Bennett 1966). When the Hoplostelis female leaves the nest, it seals the nest with resin until returning to continue killing host cells and parasitizing the suitable ones (Bennett 1966). If parasitism is interrupted and host females return to the nest, Hoplostelis eggs or larvae will be killed by the Euglossa female upon detection.
Hoplostelis is restricted to neotropical Central and South America. The subgenus Hoplostelis ranges from Jalisco, Mexico and the Yucatan Peninsula south to Bolivia and Santa Catarina, Brazil (Michener 2007). They are also represented in Trinidad (Michener 2007). The subgenus Rhynostelis occurs in Amazonas, Brazil (Michener 2007).