T. Eltz;  C. Bause;  K. Hund;  J. J. G. Quezada-Euan; T. Pokorny (2015) Correlates of perfume load in male orchid bees. Chemoecology 25: 193-199. DOI 10.1007/s00049-015-0190-9

Abstract 

Male neotropical orchid bees collect volatile substances from their environment and compose complex, species-specific odour blends in leg pouches. These perfumes are accumulated by the males over time and are exposed during pre-mating display. It has been hypothesized that perfumes are indicators of male genotypic quality and that females chose mates by the quality or intensity of their odour. Because direct experimental proof is lacking, we investigated whether the amount or complexity of male perfumes is related to male (1) size, (2) fluctuating (left–right) asymmetry, or (3) age, traits that are known to be sexually selected in other animals. We measured left and right forewings (cell node distances for 1 and 2, wing wear for 3) of Euglossa dilemma and Euglossa viridissima collected during dry and rainy seasons on the Yucatán peninsula, Mexico (total N = 768). Wing size was not related to the quantity or the complexity of perfume extracts in either species after excluding the effect of season, which positively affected both size and perfume load in E. dilemma. Wing asymmetry had also no effect, except in rainy season E. viridissima, where it was positively (not negatively) correlated with the quantity of perfume. Wing wear, an established age indicator of orchid bees, had the only consistent overall effect, being positively correlated with perfume amount and complexity in both species. This is in agreement with the idea that perfumes are an honest indicator of male survival capacity.

 

PDF Chemoecology 

L. A. Medina-Medina, A. G. Hart, F. L.W. Ratnieks (2014) Waste management in the stingless bee Melipona beecheii Bennett (Hymenoptera: Apidae). Sociobiology 61: 428-434

Abstract

Waste management is important in insect societies because waste can be hazardous to adults, brood and food stores. The general organization of waste management and the influence of task partitioning, division of labor and age polyethism on waste processing were studied in three colonies of the tropical American stingless bee Melipona beecheii Bennett in Yucatán, Mexico. Waste generated in the colony (feces, old brood cells, cocoons, dead adults and brood) was collected by workers throughout the nest and taken to specific waste dumps within the nest. During the day, workers based at the waste dumps formed waste pellets, which they directly transferred in 93% of cases, to other workers who  subsequently removed them from the nest. This is an example of task partitioning and is hypothesized to improve nest hygiene as has been found in leafcutting ants, Atta. To investigate division of labor and age polyethism we marked a cohort of 144 emerging workers. Workers forming waste pellets were on average 31.2±6.5 days old (±SD, N= 40, range of 18-45 days). The life span of M. beecheii workers was 49.0±14.0 days (N= 144). There was no difference in the life span of workers who formed (52.2±11.6 days, N= 40) or did not form (49.9±11.5 days, N= 97) waste pellets, suggesting that waste work did not increase mortality. Although waste was probably not hazardous to adults and brood, because the dumps are located outside the brood chamber, its presence inside the nests can attract phorid flies and predators, which can harm the colony.

  

 

PDF Sociobiology

C. Ruiz, W. de J. May-Itzá, J.J.G. Quezada-Euán, P. de La Rúa (2014) Utility of the ITS1 region for phylogenetic analysis in stingless bees: a case study of the endangered Melipona yucatanica Camargo, Moure and Roubik (Apidae: Meliponini). Sociobiology 61: 470-477

 Abstract
The internal transcribed spacers of the ribosomal RNA gene have been recently proposed as an appropriate marker for genetic analysis of the molecular variation of stingless bees. Herein we report the characterization of the complete ITS1 region in two populations (from Mexico and Guatemala) of the endangered Melipona yucatanica Camargo, Moure and Roubik. Phylogenetic analyses showed low genetic variation  between populations but defined a geographic structure with Mexican and Guatemalan specimens forming two well supported clades. Low ITS1 genetic variation found between populations contrasts with high genetic variation found in other markers.  Phylogenetic analysis corroborates the inclusion of M. yucatanica within the subgenus  Melipona sensu stricto based on previous morphological studies. The results highlight  the utility of the ITS1 for the characterization of stingless bee populations.

 

PDF Sociobiology

JO Macías-Macías, JJG Quezada-Euán, JM Tapia-Gonzalez, F Contreras-Escareño (2014) Nesting sites, nest density and spatial distribution of Melipona colimana Ayala (Hymenoptera: Apidae: Meliponini) in two highland zones of Western, Mexico. Sociobiology 61(4): 423-427

Abstract

Melipona colimana Ayala is endemic to the temperate forests of western Mexico and may be in conservation risk due to forest exploitation. Differences between the density of nests, nesting sites and spatial distribution in two places with different levels of human disturbance were established. A preserved (P) and a disturbed area (D) were identified: the forest had not been exploited for more than 18 years in the P zone, while there had been recent forest exploitation of D zone in less than two years. It was determined that nesting sites, nest density and the number of potential nest sites were predominant in the P zone. In total, 27 of 30 colonies were found on oak trees (Quercus laurina) with a diameter at breast height of 183.4 ± 34.21 cm which shows a close relationship of this bee species with this type of tree. A positive correlation between the DBH of the nesting sites in relation to the trees with nests and the presence of cavities was found. The nests are distributed in the form of aggregates in P and D zones (R = 0.31 and 0.39) with a density of 0.17 haˉ¹ and 0.04 haˉ¹ colonies respectively. Forestry exploitation seems to be affecting wild populations since the trees that bees use as nesting sites are destroyed in D zone.

PDF Sociobiology