William de Jesús May-Itzá

Paternity frequency and maternity of males in some stingless bee species

In monogynous hymenopteran societies, the number of mates of a queen strongly influences the potential for conflict between workers and queens over the maternity of males. Queens always ‘prefer’ their own sons to sons of workers, regardless of queen mating frequency. When a queen mates once, workers are more closely related to, and therefore are expected to prefer, their own sons and then sons of sisters to sons of the queen. However, if effective paternity frequency exceeds 2, workers on average should prefer queen‐produced males to males produced by their sisters. We studied the queen mating frequency of seven stingless bee species: the Mexican species Scaptotrigona mexicana, S. pectoralis and the Australian species Austroplebeia symei, Trigona clypearis, T. hockingsi, T. mellipes and T. sapiens. We then determined whether males arise from eggs laid by workers or queens in A. symei, T. clypearis, T. hockingsi and T. mellipes. We show that all seven species investigated are most likely singly mated and that the queen dominates reproduction. This indicates that the queens mating frequency alone does not determine whether workers or the queen produces the males.

Meliponiculture in Mexico: problems and perspective for development

Beekeeping with stingless bees (meliponiculture) in Mexico is an ancient tradition which today is in the process of disappearing as a consequence of changes in cultural, economic and ecological factors. This article reviews the historical background of meliponiculture as well as its potential uses in Mexico. Meliponiculture could be revived, providing an important source of income for peasant farmers in areas where the use of Africanized honey bees is restricted, provided technical and marketing problems are solved. We outline the current weaknesses and the changes needed to exploit these bees to their full potential for honey and wax production and use in other activities such as pollination.

Geometric morphometrics of the wing as a tool for assigning genetic lineages and geographic origin to Melipona beecheii (Hymenoptera: Meliponini)

The stingless bee Melipona beecheii presents great variability and is considered a complex of species. In order to better understand this species complex, we need to evaluate its diversity and develop methods that allow geographic traceability of the populations. Here we present a fast, efficient, and inexpensive means to accomplish this using geometric morphometrics of wings. We collected samples from Mexico, Guatemala, El Salvador, Nicaragua, and Costa Rica and we were able to correctly assign 87.1% of the colonies to their sampling sites and 92.4% to their haplotype. We propose that geometric morphometrics of the wing could be used as a first step analysis leaving the more expensive molecular analysis only to doubtful cases.

Morphometric and genetic differentiation in isolated populations of the endangered Mesoamerican stingless bee Melipona yucatanica (Hymenoptera: Apoidea) suggest the existence of a two species complex

The stingless bee Melipona yucatanica is a rare species only found in preserved forests across Mesoamerica. Morphometric and molecular analyses (DNA barcoding of the cytochrome oxidase (cox1) and microsatellites) were combined to characterize and compare populations from Mexico and Guatemala. We aim to test the hypothesis predicting that populations from these two geographic regions could be considered as distinct taxonomic units. Morphometric analyses revealed geographic differences, Guatemalan bees being larger than Mexican specimens. Bayesian analyses of the mitochondrial cox1 region and the microsatellite loci demonstrated that M. yucatanica form two clades corresponding to the Mexican and Guatemalan populations. These results suggest that M. yucatanica from Mexico and Guatemala could represent two distinct species. However, more studies are needed on their ecology and behavior to determine the possibility of gene flow between them.

Genetic and phenotypic differentiation in endemic Scaptotrigona hellwegeri (Apidae: Meliponini): implications for the conservation of stingless bee populations in contrasting environments

Abstract.  1. The western forests of Mexico are rich in species of stingless bee, possibly a consequence of the diverse habitats found across different altitudes of the Trans‐Mexican Volcanic Belt (TMVB) and the Pacific coast (PAC).

Partial Seasonal Isolation of African and European-Derived Apis mellifera (Hymenoptera: Apidae) Drones at Congregation Areas from Subtropical Mexico

Abstract The genetic interactions between European and African-derived honey bees in the Neotropics are unclear. To study the abundance of males of each type, two apiaries with colonies of African-derived honey bee and European honey bee origin were established in the surroundings of one drone congregation area. The frequencies of African-derived honey bee and European honey bee males in the mating area were studied by taking samples of drones at the drone congregation area twice a month for 5 mo. Drones from each type of colony were identified by the use of two allozyme polymorphic systems: malate dehydrogenase (Mdh), hexokinase (Hk), and by haplotype using the EcoRI site of the mitochondrial DNA. The results of a Fisher exact test showed that, although Mdh alleles had similar frequencies across the time of study (P = 0.095), the frequency of Hk alleles and haplotypes in drones varied between months (P = 0.0001). Early in March, the frequencies of African-derived honey bee-typical alleles were significantly higher compared with European honey bee-typical alleles. However, at the end of the season of drone production in July, European honey bee-typical alleles were significantly more frequent in drones than those of the African-derived honey bee type. The results mirror the findings of an early peak of drone brood production reported for African-derived honey bee colonies compared with a peak later in the year in European honey bee ones. It is concluded that the seasonal frequencies of African-derived honey bee and European honey bee drones in the mating areas are not static. They vary in accordance with the different peaks of male production in their respective colonies. This behavior may act as a partial genetic barrier between bee types. The implications of these findings with respect to current levels of Africanization in this region of Mexico and for queen rearing in Africanized areas are discussed.

Morphometric and genetic analyses differentiate Mesoamerican populations of the endangered stingless bee Melipona beecheii (Hymenoptera: Meliponidae) and support their conservation as two separate units

Phenotypic and molecular differences were previously found in populations of the endangered stingless bee Melipona beecheii from two extremes of its geographic range. In this study we combine the use of morphometric and molecular tools, with the aim of investigating patterns of phenotypic and molecular variation in populations across Mesoamerica. Morphometric analyses showed that bees from Mexico have significantly smaller body size compared with populations from Central America, forming two separated groups. Bayesian analysis of the ITS1 spacer of the ribosomal gene also showed the existence of two clusters: one composed by the Mexican populations, and another in which the Central American ones assembled (Guatemala, El Salvador, Nicaragua and Costa Rica). The combined results confirm the presence of two taxonomic units: one distributed in southern Mexico (ranging from the Yucatan peninsula to the north of Guatemala), and a Central American unit found from the southern part of Guatemala down to Costa Rica. These units should be considered separately under conservation programs and therefore, human assisted colony exchange between them should be avoided.

Intraspecific variation in the stingless bee Melipona beecheii assessed with PCR-RFLP of the ITS1 ribosomal DNA

In previous works, significant variation in morphometric and molecular characteristics was detected among populations of M. beecheii. Here RFLP tests of the internal transcribed spacer 1 of the ribosomal gene were performed to confirm those results and to evaluate the intraspecific variability within the species. The complete ITS1 region and the flanking regions showed length variation (1720 to 1670) and also three different restriction patterns that allowed differentiation of three groups of colonies with different geographic distribution. Mexican colonies from Yucatán, Campeche and Chiapas, together with one colony from northern Guatemala formed one group, a second was composed of colonies from southern Guatemala, El Salvador and Costa Rica and a third one corresponded to one colony from San Marcos (Guatemala but close to the Mexican border). Such test could be used to characterize locally adapted ecotypes subject to conservation efforts.ZusammenfassungMolekulare Analysen an Melipona beecheii, einer in den amerikanischen Tropen einheimischen Stachellosen Biene, ermöglichten die Charakterisierung der Populationen über das gesamte Verbreitungsgebiet von Mexiko bis Costa Rica (Tab. I). Als molekularen Marker wählten wir die interne transkribierte Region 1 eines ribosomalen Gens. Dieser Marker wurde bereits zur populationsgenetischen Charakteri-sierung von drei brasilianischen Melipona-Arten eingesetzt (Fernandes-Salomão et al., 2005) und erwies sich auch als nützlich in intraspezifischen Untersuchungen der brasilianischen Art M. subnitida (Cruz et al., 2006). Die ITS1-Region der von uns untersuchten Art erwies sich als besonders komplex und lang (1670–1720 Basenpaare), so dass einfache Analysen zu Restriktionsfragment-Längenpolymorphismen (RFLP) möglich waren. Von den zehn verwendeten Restriktionsenzymen erwiesen sich vier als besonders geeignet und erlaubten die Trennung von drei RFLP-Mustern (Abb. 1 und 2). Die geographische Verteilung der Kolonien, von denen die Proben stammten, stimmte mit der Verteilung der unterschiedlichen RFLP-Muster überein und bestätigte damit die Unterschiedlichkeit von drei Populationen (Abb. 3). Diese können deshalb als an jeweils lokale Umweltbedingungen angepasste Ökotypen aufgefasst werden. Die Kolonien aus Mexiko (Yucatán, Campeche und Chiapas) bildeten zusammen mit den Kolonien des nördlichen Guatemala eine gemeinsame Gruppe, eine zweite umfasste Völker aus dem Süden Guatemalas, aus El Salvador und Costa Rica, und eine dritte Gruppe bildeten Völker aus San Marcos (eine nahe der mexikanischen Grenze gelegenen Region Guatemalas). Da wilde Melipona-Populationen von einer Habitatfragmentierung der Wälder stark betroffen sein können, bildet die genetische Information aus den RFLP-Analysen der ITS1 Region der M. beecheii Völker eine Grundlage für die Etablierung von Managementstrategien und Schutzmassnahmen für die Erhaltung dieser Art.

Thirty years after: a survey on the distribution and expansion of Africanized honey bees (Apis mellifera) in Peru

SUMMARY Peru is one of the first South American countries colonized by Africanized honey bees (AHB). Paradoxically, little information is available on the distribution and economic impact of AHB on the beekeeping industry of the country. In this study we report the results of a survey of 186 managed colonies sampled during July 2000 in 16 departments of Peru covering all climatic environments within two transects. Morphometric classification showed that AHB colonies were found in all the Peruvian departments under study. However, the occupation of the Peruvian territory by AHB has produced varied levels of Africanization. Only 53% of the colonies were of ‘pure’ Africanized morphotype, whilst 30% were of intermediate African-European categories and 17% were of ‘pure’ European morphotype. There were also significant differences in the percentage of AHB colonies between departments and transects: the tropical departments and transects of the east were practically saturated with AHB colonies, but the tropical areas of the western Pacific coast showed more predominance of European honey bee (EHB) colonies. These results suggest that hybridization between EHB and AHB in western Peru has occurred as a result of reduced numerical advantages of the latter, in this case, due to a geographic barrier limiting the continued influx of AHB swarms. Currently, the beekeeping industry in Peru is increasing which probably reflects the adaptation of a new generation of beekeepers to AHB. We suggest that the establishment of national plans for selection and transfer of technology are feasible given the great potential for beekeeping in Peru.

A geometric morphometric and microsatellite analyses of Scaptotrigona mexicana and S. pectoralis (Apidae: Meliponini) sheds light on the biodiversity of Mesoamerican stingless bees

Geometric morphometrics and molecular methods are effective tools to study the variability of stingless bee populations and species that merit protection given their worldwide decline. Based on previous evidence of cryptic lineages within the Scaptotrigona genus, we tested the existence of multiple evolutionary lineages within the species S. mexicana and we investigated the status of S. pectoralis. By analyzing their population structure, we found differences between the Pacific and Atlantic populations of each of these species, although geometric morphometrics of the wing only confirmed these results in S. mexicana. There was a tendency towards enhanced genetic differentiation over larger distances in the Atlantic populations of both species but not in the Pacific populations. These results revealed a pattern of differentiation among evolutionary units and a specific distribution of genetic diversity within these Scaptotrigona species in Mesoamerica, suggesting the need for future taxonomic revisions, as well as activities aimed at management and conservation.