Leopoldo Jesús Alvarez

Universidad Nacional de La Plata | UNLP · División de Entomología

We list the 511 species of Apoid wasps (Hymenoptera: Apoidea: Ampulicidae, Crabronidae and Sphecidae), recorded up to now from Argentina, and a key to the three families, 11 subfamilies, 25 tribes and 83 genera known from the country. We also give the distinctive characters to recognize the members of this cluster of families, and summarize data on...

We provide a list of the 282 species of Vespidae (Hexapoda: Hymenoptera: Aculeata), recorded up to now from Argentina, and a key to the 46 genera known from the country. We also provide the distinctive characters to recognize the family, and summarize data on distribution, systematics, diversity, and biology of the family, as well as the most recen...

Este guia nasce a partir da observação dos encontros entre a sociedade e a natureza. Apresenta aos leitores o universo de um grupo de insetos maravilhosos e intrigantes a partir de uma perspectiva de diferentes olhares sobre as abelhas sem ferrão, que reflete tanto o conhecimento da população local quanto o dos pesquisadores de ciências naturais. O...

Pronomopsis rubripes Hermann, and Pronomopsis talabrensis Artigas are reported for the first time from Argentina (Salta and Jujuy) and the male terminalia of P. chalybea Hermann and P. talabrensis are described and illustrated for the first time. An updated distribution map and a key of the species of Pronomopsis Hermann are also provided.

The palm Euterpe edulis is an important palm species for the extraction of palm heart, a highly profitable consumable product. Due to its importance, much research has been conducted around the ecology of this palm species. Nevertheless, information available on its reproductive ecology is quality-deficient and fragmented, resulting in misleading v...

A new species of Plebeia Schwarz (Hymenoptera: Apidae) from Argentina is described and illustrated. Plebeia mansita Alvarez & Rasmussen sp. nov. occurs in the extreme northwest of the country and is restricted to the biogeographic province of the Yungas, where it is found at altitudes above 1,000 m. Observations on behavior, biology and nesting sub...

The knowledge of the entomological fauna in productive systems is important for the agroecological management since beneficial insects are a key resource for pest management in horticultural systems. Scientific information on the biodiversity present in a given area is essential as well as the ecological function and/or feeding habits of the insect...

This study estimates the diversity, abundance and floral associations of native wild bees present in a nature reserve in Buenos Aires, Argentina. The study included monthly sampling from September to April for two consecutive seasons (2011-2013). Bees were collected using entomological nets and pan traps along transects in the reserve area. A total...

The genus Bombus is represented by 38 subgenera around the world with nearly 250 described species. They are among the most efficient insect pollinators and therefore important to the ecology and the economy. In Argentina, this genus it is represented by eight native and two introduced species. Several bee pathogens related to colony losses have be...

Here we provide descriptions of gynandromorphs of two species oil-collecting bees: Lophopedia nigrispinis and Epicharis iheringii, both with partial bilateral phenotypic asymmetry. The bees have a female phenotype predominantly on mesosoma and metasoma. The specimen of L. nigrispinis has distinct characteristics on legs, suggesting a mosaic pattern...

Bumblebees are economically important insects which perform essential pollination tasks in natural and managed ecosystems. Recent research studying Neotropical bumblebee species in Brazil showed a clear decrease in genetic diversity over time in Bombus pauloensis. A new temporal assessment of genetic diversity is needed to know whether this was a l...

In this study, we record for the first time the genus Notocyrtus (Heteroptera, Reduviidae) from Argentina based on three species: Notocyrtus dorsalis (Gray), Notocyrtus dispersus Carvalho & Costa, and Notocyrtus foveatus Stål. We also describe and illustrate a mimetic complex comprising the three Notocyrtus species and Tetragona clavipes (Fabricius...

A new species of Trigonisca is described for northwestern Argentina, Trigonisca sachamiski sp. nov., of Salta and Jujuy provinces. Distribution maps, comparative notes and a synopsis of Nannotrigona and Lestrimelitta present in Argentina are also given. Nannotrigona melanocera and Lestrimelitta rufa are reported for the first time in Argentina and...

The Meliponini is a eusocial group of bees tropically distributed. In Argentina, 37 species have been recorded, mostly in Misiones province. They use a great variety of sites to build their nests including tree hollows, cavities formed in rocks, human constructions or underground spaces. Numerous natural enemies are associated with stingless bees,...

Besides the incipient research effort, the role of parasites as drivers of the reduction affecting pollinator populations is mostly unknown. Given the worldwide extension of the beekeeping practice and the diversity of pathogens affecting Apis mellifera populations, honey bee colonies are a certain source of parasite dispersion to other species. H...

The southern distribution of stingless bees in the Neotropics reaches the province of Buenos Aires, Argentina, up to 34°51' S in latitude, where two species of Plebeia are found on the west margin of the Río de La Plata: P. emerinoides (Silvestri), and P. droryana (Friese). In this area some relicts of gallery forest occur and the climate is modera...

Abstract: Description of a new species of Plebeia Schwarz, key to Argentine species of Plebeia, and comments on Plectoplebeia in Argentina (Apidae: Meliponini). A new species of Plebeia is described and figured from the Paranaense forest of Misiones, Argentina. Plebeia guazurary Alvarez, Rasmussen & Abrahamovich, new species, is distinguished from...

Esta Guía nace de la observación sobre los encuentros entre sociedad y naturaleza. La idea es introducir a los lectores al universo de un grupo de insectos maravillosos e intrigantes desde una perspectiva que busca el diálogo entre miradas y refleja tanto los saberes de pobladores locales como el de investigadores de las ciencias naturales sobre la...

The nesting biology of the exotic bee Megachile (Eutricharaea) concinna Smith, 1879 and its negative interactions with other insects were studied. Trap nests made of wood were located in an urban environment in Buenos Aires province, Argentina, and surveyed during 26 months. The lifecycle and the structure of the nest of M. concinna are described....

We describe and figure the previously unknown male of Hypanthidioides (Ctenanthidium) bifasciata (Urban, 1993) based on specimens reared from a trap nest along with a female. This species, originally known only from the type specimen collected in Colonia, Uruguay, is also newly recorded from Buenos Aires, Argentina. We provide for the first time in...

Melittobia hawaiiensis Perkins (Hymenoptera: Eulophidae), a common gregarious ectoparasitoid of aculeate Hymenoptera and other orders of insects, is reported for the first time as a parasitoid of Melitoma segmentaria (Fabricius) (Hymenoptera: Apidae) in Buenos Aires, Argentina.

Two new records of gynandromorphism in bees are described and illustrated for Paratrigona glabella and Augochlora amphitrite. The specimens show a mixture of male and female features, complete in Augochlora and on head and mesosoma in Paratrigona. Including the specimen described herein, gynandromorphs are now known for a total of three species in...

The wood-boring bee Lithurgus huberi Ducke (Apidae: Megachilinae: Lithurgini) is arguably an exotic species to South America. This solitary bee is the only representative in the Western Hemisphere of the Old World genus Lithurgus, and likely a conspecific with the Indo-Australian species Lithurgus atratus. L. huberi appears to have reached the cont...

A systematic revision of the species of the genus Xylocopa subgenus Neoxylocopa in Argentina is provided. Seven species are included: X. atamisquensis Lucia & Abrahamovich, X. augusti Lepeletier, X. eximia Pérez, X. frontalis (Olivier), X. mendozana Enderlein, X. nigrocincta Smith and X. tacanensis Moure. The males of X. eximia and X. nigrocincta a...

El cultivo de berenjena tiene en muchos países gran importancia económica, por este motivo actualmente se encuentra en amplia expansión a nivel mundial. En este trabajo se estudiaron las abejas asociadas a este cultivo producido en invernadero en la zona hortícola de La Plata, Buenos Aires, Argentina. Se reconocieron un total de 21 especies de abej...

The identity of Stenocolletes Schrottky and its single species, Stenocolletes pictus Schrottky, has remained a mystery since their description in 1909. Stenocolletes was originally placed in the bee family Colletidae but no known American colletid matches the original description. The type of S. pictus is likely lost as are large portions of Schrot...

Notes are provided on the morphology of males and females of the enigmatic Lithurgus huberi Ducke (Lithurginae: Lithurgini), a species historically believed to have been introduced into South America from Asia and to be a possible synonym of the more widespread L. atratus Smith. Distinctive differences are documented between L. huberi and L. atratu...

Four new gynandromorph Xylocopinae bees from Argentina are described and illustrated; one specimen of Xylocopa splendidula Latreille and three of Ceratina rupestris Holmberg. All specimens are mosaic gynandromorphs as they display mixed female-male characters in different parts of the body.

Here we report for the first time the presence of the exotic leafcutter bee Megachile (Eutricharaea) concinna in South America, based on specimens collected in the northeast part of Buenos Aires province, Argentina. We believe that M. concinna accidentally entered the country probably together with the introduction of M. rotundata to different regi...

This is the first record of the association between Walkeromya plumipes (Philippi) (Diptera: Bombyliidae) and Xylocopa Latreille (Hymenoptera: Apidae) in Argentina. The pupal development and morphology of Walkeromya plumipes, a parasitoid of Xylocopa splendidula Lepeletier, are described. A parasitized nest was collected from Santiago del Estero pr...

The primary and secondary type specimens of 27 species of sawflies housed at the Museo de La Plata (Division Entomologia), Argentina are listed. Information on kinds of types, collection data, and current status are provided. The types belong to species described by P. Jorgensen, C. Schrottky, and D. R. Smith. Two new synonymies are recognized: Aph...

We describe a mixed gynandromorph of Xylocopa (Neoxylocopa) nigrocincta from a single specimen from Argentina. The specimen presents bilateral asymmetry, with the right half of its head displaying male characters and the left half displaying female characters; the mesosoma presents male characters mostly in the right half of the prothorax, pronotal...