Phylogeny and revision of the Neotropical bee genus Rhectomia s.l. Moure (Hymenoptera, Apidae, Augochlorini)

This paper revises the bees currently considered to belong to the genus Rhectomia s.l. and proposes a species phylogeny based on morphological characters, using other Corynurina as outgroups. The results indicate that Rhinocorynura Schrottky renders Rhectomia s.l. paraphyletic. Consequently, Corynurella is removed from synonymy with Rhectomia s.s., and Paracorynurella gen.n. is proposed. The topology among these genera is: outgroup [(Rhectomia s.s. + Rhinocorynura) (Paracorynurella gen.n. + Corynurella)]. Nine species are assigned to Corynurella: C. brokopondoi sp.n., C. caerulea sp.n., C. cognata sp.n., C. decora sp.n., C. harrisoni (Engel), C. mourei Eickwort, C. nigra sp.n., C. singularis sp.n. and C. triangulata sp.n. Three new species are described in Paracorynurella gen.n.: type species P. betoi sp.n., P. excavata sp.n., P. reticulata sp.n.; P. difficillima (Ducke) comb.n. is transferred from Rhinocorynura. Three species are recognized in Rhectomia s.s.: R. catarina sp.n., R. liebherri Engel and R. pumilla Moure. The male of R. liebherri is described for the first time. Keys for the identification of the genera and species are provided.

The bee genus Caenaugochlora (Hymenoptera, Apoidea) and its constituent subgenera, with new species of Caenaugochlora s.str. from Ecuador

Two new species of Caenaugochlora Michener are described and figured from Ecuador. Caenaugochlora quichua sp. n. and C. bennetti sp. n. are both remarkable for the presence of carinate preoccipital carinae, setose compound eyes, strongly rimmed metabasitibial plate, normally pectinate inner metatibial spur, metapostnotal striae not reaching the apical margin, and the male fourth metasomal sterna with lateral projections. The combination of these features intermingle attributes of the presently recognized subgenera, while others are unique to the genus as a whole. A revised diagnosis is provided for the genus and its two subgenera, with Caenaugochlora s.str. accommodating C. bennetti and C. quichua, and brief comments made regarding the implications of the characters exhibited by the aforementioned species.

Notes and new species of the halictine genus Megommation Moure (Hymenoptera, Apidae, Augochlorini)

A new species of Megommation, M. amazonicum n. sp., is described and illustrated. An identification key for the two species of this genus is provided. Additionally, the lectotype and paralectotype of Megalopta (Megaloptella) ipomoea Schrottky are designated.

A taxonomic revision of the augochlorine bee genus Ceratalictus Moure (Hymenoptera, Apoidea)

The Neotropical halictid bee genus Ceratalictus Moure (Augochlorini) is revised. Five new species are described, Ceratalictus argentinus n. sp., C. camargoi n. sp., C. culminis n. sp., C. nitidus n. sp. and C. orthocarinatus n. sp.; five species are redescribed: Ceratalictus allostictus Moure, C. clonius (Brethes), C. ischnotes (Vachal), C. psoraspis (Vachal), and C. stigon (Vachal). Ceratalictus lorenzinis (Strand) is synonymized with C. clonius. All catalogued type specimens were examined. Illustrations of all species and an identification key for the 10 presently recognized species are provided.

Multifemale nests and social behavior in Euglossa melanotricha (Hymenoptera,Apidae, Euglossini)

The nesting biology and social behavior of the euglossine bee species Euglossa melanotricha was analyzed based on the monitoring of eight nests found in man-made cavities and transferred to observation boxes. Euglossa melanotricha females usually construct their nests in cavities in the ground, in buildings, or in mounds. In this study, we present new data on the nesting biology of E. melanotricha. The process of reactivation of nests was commonly observed with one to three females participating in the reactivation. The duration of the process of reactivation ranged from 10 to 78 days (n = 31) and were longer during the rainy season. Time spent (in days) for provisioning, oviposition and closing a single cell was higher in reactivations that occurred during the dry period. 151 emergences were observed (39 males and 112 females). 90 (80.3%) of the emerged females returned to the natal nest, but only 35(38.9%) remained and actively participated in the construction and provisioning of cells. The other 55 abandoned the nests after several days without performing any work in the nest. Matrifilial nest structure was regulated by dominance-subordinate aggressive behavior among females, where the dominant female laid almost all eggs. Task allocation was recognized by behavioral characteristics, namely, agonism and oophagy in cells oviposited by other females. Euglossa melanotricha is multivoltine and its nesting is asynchronous with respect to season. Our observations suggest a primitively eusocial organization. These observations of E. melanotricha provide valuable information for comparison with other species of Euglossa in an evolutionary context.