Nesting Biology of the Solitary Ground-Nesting Bee Diadasina riparia (Apidae: Emphorini)

We described the nesting behavior and ecology of Diadasina riparia, from an urban dry forest fragment. The nests of D. riparia were shallow with circular entrance, closed by a mud plug, from which a straight vertical tunnel ending in one or more brood cells. Most females need one day for construction and provisioning the nest. The natural enemies were flies of Anthrax genus, the cleptoparasitic bees Leiopodus trochantericus, and Mutillidae wasp. The feature about the life history, nest architecture, materials used, pollen provisions behavior and associated organisms of this species allow the comparison with other emphorines species.

Comparative biology of four Rhodanthidium species (Hymenoptera, Megachilidae) that nest in snail shells

Some species of two tribes (Anthidiini and Osmiini) of the bee family Megachilidae utilize empty gastropod shells as nesting cavities. While snail-nesting Osmiini have been more frequently studied and the nesting biology of several species is well-known, much less is known about the habits of snail-nesting Anthidiini. We collected nests of four species of the genus Rhodanthidium (R. septemdentatum, R. sticticum, R. siculum and R. infuscatum) in the Czech Republic, Slovakia, Catalonia (Spain) and Sicily (Italy). We dissected these nests in the laboratory and documented their structure, pollen sources and nest associates. The four species usually choose large snail shells. All four species close their nests with a plug made of resin, sand and fragments of snail shells. However, nests of the four species can be distinguished based on the presence (R. septemdentatum, R. sticticum) or absence (R. siculum, R. infuscatum) of mineral and plant debris in the vestibular space, and the presence (R. septemdentatum, R. infuscatum) or absence (R. sticticum, R. siculum) of a resin partition between the vestibular space and the brood cell. Rhodanthidium septemdentatum, R. sticticum and R. siculum usually build a single brood cell per nest, but all R. infuscatum nests studied contained two or more cells. For three of the species (R. siculum, R. septemdentatum and R. sticticum) we confirmed overwintering in the adult stage. Contrary to R. siculum, R. septemdentatum and R. sticticum do not hide their nest shells and usually use shells under the stones or hidden in crevices within stone walls. Nest associates were very infrequent. We only found two R. sticticum nests parasitized by the chrysidid wasp Chrysura refulgens and seven nests infested with pollen mites Chaetodactylus cf. anthidii. Our pollen analyses confirm that Rhodanthidium are polylectic but show a preference for Fabaceae by R. sticticum.

A further study of the nesting biology of Leptochilus (Neoleptochilus) regulus (de Saussure, 1855) (Hymenoptera, Vespidae, Eumeninae)

Two females of Leptochilus regulus (de Saussure, 1855) were observed nesting in reed stalks of a Fabre’s hive serving as a block of trap nests in Crimea, with the timekeeping of all their nesting behaviours. The building material used by the females to separate the nesting cavity into the cells consisted of pellets of dry soil, gravel particles, and small fragments of tree bark, leaves, and thin stems. Females rapidly carried these items collected in 1.0–1.5 m from the nests. They bonded only the last portions of the building material in each “partition” with a very small amount of mud. An additional amount of unbonded building material items was deposited into the nest after sealing the last nest cell. Females hunted exclusively for small larvae of an anobiid beetle (Coleoptera, Anobiidae); they stored 19–37 prey items per cell. Hunting and provisioning occupied the largest portion of the females’ time budget. Duration of hunting flights was different between the females. The nests of both females contained three brood cells. Cocoons of Chrysis ragusae De Stefani, 1888 (Hymenoptera, Chrysididae) were found in the nests; females of this cuckoo wasp species were also recorded entering the host nests at the stage of provisioning, acting apparently as inquilines. The cocoon ultrastructure of L. regulus is illustrated and discussed.

The resin bee subgenus Ranthidiellum in Thailand (Megachilidae, Anthidiini): nesting biology, cleptoparasitism by Stelis, and new species

Resin bees of the subgenus Ranthidiellum, are rare and endemic to Southeast Asia. These bees are known to construct resinous entrance tubes to their nests. Here, the new species Anthidiellum (R.) phuchongensissp. nov. is described along with a description of its nest collected from Phu Chong Na Yoy National Park, Ubon Ratchathani Province, Thailand. In addition, the bee cleptoparasite, Stelis (Malanthidium) flavofuscinularsp. nov., and the male of A. (R.) ignotum Engel, 2009, are described for the first time. A key to Ranthidiellum species is also provided.