Nesting and Developmental Biology of the Cleptoparasitic BeeStelis ater(Anthidiini) and Its Host,Osmia chalybea(Osmiini) (Hymenoptera: Megachilidae)

Abstract

Herein we provide the first account of the nesting biology of Osmia (Helicosmia) chalybea Smith and of its cleptoparasite Stelis (Stelis) ater Mitchell, a newly confirmed host association. The nesting behavior of O. chalybea is similar to what is known about other members of the subgenus Helicosmia, but novel information concerning egg eclosion and cocoon structure and function are reported. Eggs of S. ater were discovered both on the front surface of the host provisions as well as deeply buried in the pollen-nectar mixture. From numerous observations, larval S. ater attacks host immatures or conspecifics whenever encountered. Because young larvae are unable to crawl (perhaps a family characteristic), the hospicidal individual may be in its third to fifth stadium or even in its second stadium, although none of the latter was certainly identified. Although usually a single cleptoparasitic egg or larva was found in a cell, two or three were occasionally observed there. The cocoon of S. ater was also examined closely. Although its construction differs in a number of ways from that of the host cocoon, the functions of both seem to be the same, i.e., excluding parasitic/parasitoid arthropods and preventing desiccation while allowing exchange of air with the outside through complex filtering devices at the front ends of cocoons. Known parasites/parasitoids in the area of study include the minute parasitoid wasp Melittobia digitata Dahms (Eulophidae) and the parasitic mite Chaetodactylus rozeni Klimov 2 AMERICAN MUSEUM NOvITATES NO. 3707 and O'Connor (the latter recovered from adults of O. chalybea). The nearly airtight cocoon fabric of both bee cocoons presumably assists immatures in maintaining their water balance through their many months of confinement. Ovarian statistics for both species are presented and compared with congeners, and their eggs/mature oocytes are described. Both have five larval instars. Comparative taxonomic descriptions of last larval instars are presented, and mandibular shapes of other larval instars are diagrammed.

Biology of the Cleptoparasitic BeeMesoplia sapphirina(Ericrocidini) and Its HostCentris flavofasciata(Centridini) (Apidae: Apinae)

“…This interpretation explains the strong curvature of the egg: the lower part of the emerging head is positioned to ingest fluid from the provisions. This information has never been recorded before for any Centridini but is in agreement with observations on Eucerini (Rozen, 1964), Tapinotaspidini (Rozen et al, 2006), and on at least some Megachilidae (Baker, 1971;Torchio, 1989;Rozen and Özbek, 2004;Rozen and Kamel, 2007;Rozen and Hall, 2011).…”

Immatures of Exomalopsine Bees with Notes on Nesting Biology and a Tribal Key to Mature Larvae of Noncorbiculate, Nonparasitic Apinae (Hymenoptera: Apidae)

“…It seems likely that the thin cocoon fabric elsewhere protects the bee from desiccation while the screening at the opening helps prevent parasite/predator invasion. Although no external protrusion is notice able on the outside of the cocoon, this structure corresponds to the nippled end of megachilid cocoons that serves similar functions (Rozen and Hall, 2011). The cocoon of Anthophorula completa is similar to that described for Anthophorula sidae (Rozen, 1984) in that most of the feces of A. sidae are applied to the front end of the cell, and elsewhere the cocoon fabric is semitransparent.…”

Mature Larvae and Nesting Biologies of Bees Currently Assigned to the Osmiini (Apoidea: Megachilidae)

“…However, the presence or absence of body spicules may be a labile feature in megachilid bees, as evidenced by absence of spicules in Neofidelia mentioned above, as well as the following: in the Anthidiini Trachusa larreae (Cockerell) (Rozen and Hall, 2012), Anthidium chilense (Urban) (as Notanathidium (Allanthidium) chilense, , and Stelis (S.) elongativentris Parker are reported to have setae and spicules, whereas Stelis (S.) phaeoptera murina Pérez (Rozen and Kamel, 2009) and Stelis (S.) ater Mitchell (Rozen and Hall, 2011) have only setae.…”

“…It has been postulated that body vestiture in megachilid bees enables the mature larva to move around in its cell to finish feeding, to position its fecal deposits, and to manufacture its cocoon (Rozen and Hall, 2011Rozen, 2013a). In most of these cases two types of vestitures are involved: spicules and setae.…”