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Melipona subnitida (Hymenoptera: Apidae) is a stingless bee native to Caatinga biome in Brazil, well adapted to hot and dry climate of that region and has been traditionally explored for honey production. Here, we evaluate the genetic structure of 173 colonies of M. subnitida in northeast Brazil by partially sequenced mitochondrial genes cytochrome oxidase I (COI) to compare an introduced population isolated for 30 yr into the Island of Fernando de Noronha (IFN) with the continental populations. We identified high haplotype diversity (0.8220) with 14 haplotypes on the continental populations, being three new ones, compared with the database GenBank. The haplotype H4 was present at the center of network, occurring in four localities on mainland and fixed as a single haplotype on IFN. We propose that the island populations originally introduced carried one haplotype (H4), even though IFN population is suffering pressure by island effect through changes on morphology. Studies on island populations could be a model to understand the dynamics of isolated populations and sustainable management of this biome to preserve M. subnitida.

In the present study, we used morphological and behavioral analyses to assess the effects of seasonality and morphoclimatic patterns on the morphology, behavior, and distribution of 71 colonies of Africanized honey bees in 3 distinct ecoregions (Zona da Mata, Agreste, and Sertão) within the State of Sergipe, north-eastern Brazil. We found a high rate of gene flow among the studied colonies. However, there were pronounced morphological differences among localities and ecoregions, and body shape (r = 0.06239; P = 0.05) and size (P < 0.001) varied with altitude. Regional groups were separated by phenotypic plasticity, rather than genetic divergence. We also found a significant difference in the hygienic behavior of these populations between the dry and rainy seasons (P = 0.022; α = 0.05) and between ecoregions (P = 0.001; α = 0.05). The main modulator of hygienic behavior was the influence of temperature (ρ = 0.065; P = 0.471; α = 0.05) and altitude (ρ = -0.294; P = 0.001; α = 0.05) on rainfall (ρ = 0.274; P = 0.002; α = 0.05). This supports the hypothesis that environmental factors influence the expression of hygienic behavior trait. The influence of environmental factors on the morphology, behavior, and distribution of Africanized honey bees, together with the identified polyphenisms, indicate high genetic variability within these populations that can be exploited in future bee handling and breeding programs.

The successful distribution of A. mellifera is due to their ability to adjust to seasonal variations, considerable control over their internal physical environment and exploration of different resources. However, their populations have experienced different forms and levels of environmental pressure. This research aimed to verify the phenotypic plasticity in both size and shape of wings in A. mellifera using fluctuating asymmetry, based on geometric morphometrics from apiaries located in sites with high and low levels of anthropization. We sampled 16 locations throughout all five geographic regions of Brazil. At each site, samples were collected from 20 beehives installed in apiaries: 10 installed near high anthropogenic environments (Cassilandia - MS, Fortaleza - CE, Maringá - PR, Aquidauana - MS, Rolim de Moura - RO, Riachuelo - SE, Ubiratã - PR and Piracicaba - SP), and 10 in sites with low levels of human disturbance (Cassilândia - MS, Itapiúna CE, União da Vitória - PR, Aquidauana - MS, Rolim de Moura - RO, Pacatuba - SE, Erval Seco - RS, Rio Claro - SP). A sample of 10 individuals was taken in each hive, totaling 200 per location, for a total of 1,600 individuals. We used fluctuating asymmetry (FA) in size and shape of the forewing through geometric morphometrics. The FA analysis was conducted in order to check bilateral differences. The indexes of size and shape were submitted to analysis of variance (ANOVA), where the characters evaluated were used as factors to verify the size and shape differences. The results indicated an asymmetry on the shape of the wing (P < 0.001) but no asymmetry was observed on wing size. Considering FA as an environmental response and high and low impacted areas as a fixed factor, we observed significant differences (P < 0.05). The results for the wing shape in A. mellifera demonstrated that this feature undergoes more variation during ontogeny compared to the variation in size. We concluded that bee samples collected from colonies with higher levels of human disturbance had higher wing-shape asymmetry; the variation of fluctuating asymmetry in the wing shape of honeybees can be used as an indicator of the degree of environmental anthropization.

This study aimed to identify differences in wing shape among populations of Melipona quadrifasciata anthidioides obtained in 23 locations in the semi-arid region of Bahia state (Brazil). Analysis of the Procrustes distances among mean wing shapes indicated that population structure did not determine shape variation. Instead, populations were structured geographically according to wing size. The Partial Mantel Test between morphometric (shape and size) distance matrices and altitude, taking geographic distances into account, was used for a more detailed understanding of size and shape determinants. A partial Mantel test between morphometris (shape and size) variation and altitude, taking geographic distances into account, revealed that size (but not shape) is largely influenced by altitude (r = 0.54 p < 0.01). These results indicate greater evolutionary constraints for the shape variation, which must be directly associated with aerodynamic issues in this structure. The size, however, indicates that the bees tend to have larger wings in populations located at higher altitudes.

We examined the spatial implications of maximum flight distance for several species of stingless bees. Data suggested that maximum flight distance in Meliponini is a function of body size, especially generalized wing size, which can be estimated through principal component analysis. For six species of stingless bees, flight distances and generalized wing sizes were highly correlated (r = 0.938). This indicates that species of Meliponini occupy an effectively larger area as body size increases, which has important implications in the spatial dynamics of local populations restricted to forest fragments. We also used the fitted linear regression model to estimate the maximum flight distance for 12 other species of Meliponini. The results of this research may provide insights for future studies of biological conservation.

The recently developed geometric morphometrics methods represent an important contribution of statistics and geometry to the study of biological shapes. We propose simple protocols using shape distances that incorporate geometric techniques into linear quantitative genetic models that should provide insights into the contribution of genetics to shape variation in organisms. The geometric approaches use Procrustes distances in a curved shape space and distances in tangent spaces within and among families to estimate shape heritability. We illustrate the protocols with an example of wing shape variation in the honeybee, Apis mellifera. The heritability of overall shape variation was small, but some localized components depicting shape changes on distal wing regions showed medium to large heritabilities. The genetic variance-covariance matrix of the geometric shape variables was significantly correlated with the phenotypic shape variance-covariance matrix. A comparison of the results of geometric methods with the traditional multivariate analysis of interlandmark distances indicated that even with a larger dimensionality, the interlandmark distances were not as rich in shape information as the landmark coordinates. Quantitative genetics studies of shape should greatly benefit from the application of geometric methods.