jueves, 23 de octubre de 2014
Tesis de Maestría: Efectos de la inoculación de esporas de Nosema ceranae (Microsporidia) y detección del virus de alas deformes (DWV) en la abeja nativa sin aguijón Melipona beecheii (Hymenoptera: Meliponini) en Yucatán , México.
Asesores: Dr Luis Medina Medina, Dr William May Itzá
viernes, 3 de octubre de 2014
Pokorny T., Loose D., Dyker G., Quezada-Euán J.J.G., Eltz T. (2015) Dispersal ability of male orchid bees and direct evidence for long-range flights. Apidologie 46: 224-237. DOI 10.1007/s13592-014-0317-y
Male Neotropical orchid bees collect volatile chemicals from various sources in the environment in order to compose their characteristic perfume bouquets. Amongst other plants, over 600 species of orchids are exclusively pollinated by the bees during their quest for volatiles. Since the plants usually have a scattered distribution, it is assumed that orchid bees can transport the pollinaria across several kilometres due to their flight capabilities and a high dispersal potential. Until now, very long-range flight distances (up to 45 km) of male orchid bees have only been indirectly inferred from habitat requirements of orchids whose pollinaria were carried by captured males, whereas the distances established by direct measures (mark and recapture, radio telemetry) only span distances of up to around 6 km. The discrepancy between inferred and proven distances led us to readdress the question of dispersal ability of male orchid bees. In this study, we used tag, scratch and chemical marking of large numbers of bees to clarify two aspects: (1) the effect of moderate natural obstacles on dispersal and (2) the possibility of very long-range movements across a terrain lacking such obstacles. Our results suggest that a moderate natural obstacle (a valley separating opposite ridges) does not restrain orchid bee movements. Individual bees achieved extraordinary flight distances of more than 50 km across even terrain, extending the directly proven flight distances of male bees by more than an order of magnitude.
Afik O., Delaplane K. S., Shafir S., Moo-Valle H., Quezada-Euán J. J. G. (2014) Nectar minerals as regulators of flower visitation in stingless bees and nectar hoarding wasps. J. Chem. Ecol. 40:476–483. DOI 10.1007/s10886-014-0455-8.
Various nectar components have a repellent effect on flower visitors, and their adaptive advantages for the plant are not well understood. Persea americana (avocado) is an example of a plant that secretes nectar with repellent components. It was demonstrated that the mineral constituents of this nectar, mainly potassium and phosphate, are concentrated enough to repel honey bees, Apis mellifera, a pollinator often used for commercial avocado pollination. Honey bees, however, are not the natural pollinator of P. americana, a plant native to Central America. In order to understand the role of nectar minerals in plant—pollinator relationships, it is important to focus on the plant’s interactions with its natural pollinators. Two species of stingless bees and one species of social wasp, all native to the Yucatan Peninsula, Mexico, part of the natural range of P. americana, were tested for their sensitivity to sugar solutions enriched with potassium and phosphate, and compared with the sensitivity of honey bees. In choice tests between control and mineral-enriched solutions, all three native species were indifferent for mineral concentrations lower than those naturally occurring in P. americana nectar. Repellence was expressed at concentrations near or exceeding natural concentrations. The threshold point at which native pollinators showed repellence to increasing levels of minerals was higher than that detected for honey bees. The results do not support the hypothesis that high mineral content is attractive for native Hymenopteran pollinators; nevertheless, nectar mineral composition may still have a role in regulating flower visitors through different levels of repellency
May-Itzá W. de J., Medina Medina L. A., Medina S., Paxton R. J., Quezada-Euán J. J. G. (2014) Seasonal nest characteristics of a facultatively social orchid bee, Euglossa viridissima, in the Yucatan Peninsula, Mexico. Insect. Soc. 61: 183-190.
Euglossines have long been regarded as largely solitary, though some species are known to exhibit social behavior. We studied the nesting behavior of Euglossa viridissima over an annual cycle, comparing sociality and offspring production across the rainy (RS) and dry seasons (DS) in the Yucatan Peninsula of Mexico. Nests were built in both the RS and the DS, but with greater nest initiation and brood provisioning in the RS, presumably as a consequence of more floral resources at this time of year. Across the year, numerical sex ratios were female biased (0.7 as females/total); sex ratios varied across individual nests from 0.3 to 1.00, though without a clear relationship to sociality. Egg-to-adult development was quicker in females than males and, within a sex, quicker when ambient temperatures were higher. Multi-female (social) nests were only founded at the end of the RS and the beginning of the DS, coincided with the presence of Hymenopteran and Dipteran parasites in nests headed by solitary females. Reduced floral resources and a higher risk of parasitism, possibly coupled with higher female density or reduced nesting sites, may be factors favoring the formation of multi-female associations in this euglossine. Better nourishment of foundress females in the RS may improve lifespan and permit overlapping generations which, coupled with the kin structure of their nests, may favor social nesting in E. viridissima.
Pokorny T., Lunau K., Quezada-Euan J. J. G., Eltz T. (2014) Cuticular hydrocarbons distinguish cryptic sibling species in Euglossa orchid bees. Apidologie 45: 276-283.
Cuticular lipid profiles have been shown to be species specific within many insect genera, allowing a chemotaxonomic classification of individuals. In this study, we analysed the cuticular lipids of the orchid bees Euglossa viridissima Friese and Euglossa dilemma Bembé & Eltz, cryptic sibling species whose taxonomic status has only recently been clarified. Male individuals of both species were obtained from two locations on the Yucatán Peninsula, Mexico, both in the dry and wet seasons. Their hydrocarbon profiles proved to be species specific, irrespective of location and season. They also allowed a correct assignment of a rare morph of E. viridissima which had long obscured the distinction of the two species. Our results suggest that cuticular hydrocarbon profiles may be suited for chemical taxonomy of orchid bees and might provide an additional clue for difficult species distinctions.
Ruiz C., May-Itza W. de J., Quezada-Euán J. J. G., De la Rúa P. (2013) Presence of nuclear copies of mitochondrial origin (NUMTs) in two related species of stingless bee genus Melipona (Hymenoptera: Meliponini). J. Zool. Syst. Evol. Res. 51: 107-113. DOI: 10.1111/jsz.12011 ISSN: 0947-5745
Transferred copies of mitochondrial DNA (mtDNA) into the nuclear genome (numts) have been reported in several Hymenoptera species, even at a high density in the honey bee nuclear genome. The accidental amplification of numts in phylogenetic studies focused on mtDNA highlights the importance of a correct determination of numts and their related mtDNA sequences. We report here the presence of numts derived from a mitochondrial rDNA 16S gene in the genome of the stingless bee species Melipona colimana and M. fasciata (tribe Meliponini) from Western Mexico. PCR products were cloned in both species obtaining thirty paralogous numts. Numts were identified by the presence of insertions and deletions and the disruption of the 16S secondary structure. Further phylogenetic analyses including alternative mitochondrial cox1 and nuclear ITS1 genes have revealed the presence of another numt (cox1) in the nuclear genome of these two species, and place both as sister lineages within the subgenus Michmelia. This is one of the first studies reporting the presence of numts in Meliponini species, and supports previous studies suggesting frequent transfer of mtDNA to the nuclear genome in Hymenoptera.
Quezada-Euán J J G, Ramírez J, Eltz T, Pokorny T, Medina R, Monsreal R (2013) Does sensory deception matter in eusocial obligate food robber systems? A study of Lestrimelitta and stingless bee hosts. Animal Behaviour 85: 817-823 ISSN:0003-3472. http://dx.doi.org/10.101/j.anbehav.2013.01.028
AbstractSocial parasites can break into their host colonies using sensory deception, force, or both. To evaluate the role of sensory deception in eusocial obligate food robbers, we studied the Mesoamerican stingless bee Lestrimelitta niitkib–host species system, including preferred and nonpreferred host species. The use of citral as a propaganda substance is documented in L. niitkib, but possible mechanisms used by individual scouts to overcome host species recognition have not been studied. We analysed the cuticular profiles of L. niitkib and host species, coupled with bioassays of time to aggression (latency) and included data on host species raid frequency. We found that L. niitkib has a simple, but not insignificant, cuticular profile. Generally, L. niitkib cuticular profiles were similar to (but did not mimic) profiles of its preferred host species and differed from profiles of nonpreferred hosts. As expected, latency generally fitted a recognition system based on the degree of similarity between the cleptobiont's cuticular label and the host species template, with chemically similar species reacting slower and chemically distant species reacting rapidly to L. niitkib. There was a positive correlation between raid ratio and latency, indicating that the speed of detection and aggression towards L. niitkib scouts could influence host species selection. Cuticular profile similarity of individual L. niitkib scouts to host species may help L. niitkib scouts evade recognition and attacks from guards. In a further step, unnoticed L. niitkib scouts could successfully recruit nestmates to mass-raid host species colonies. The fact that L. niitkib can also plunder aggressive species, suggests that obligate cleptobiosis within its narrow biological niche could be characterized by flexibility in invasion strategies to allow exploiting a broad range of host species and be successful over evolutionary times.
Hurtado-Burillo, M; Ruiz, C; May-Itzá William de J., Quezada-Euán J. Javier G; De La Rúa Pilar. 2013. Barcoding stingless bees: genetic diversity of the economically important genus Scaptotrigona in Mesoamerica. Apidologie 44:1–10.
The stingless bee genus Scaptotrigona is widely distributed across tropical Mexico and includes economically important species used in stingless beekeeping. As Scaptotrigona colonies are currently or potentially translocated across regions, it is important to analyze the extent of genetic diversity from different populations. Herein, every analyzed Scaptotrigona individual was correctly assigned through DNA barcoding to the three recognized species (Scaptotrigona mexicana, Scaptotrigona pectoralis, and Scaptotrigona hellwegeri). Intraspecific divergence showed a mean value of 0.70 %, whereas the interspecific value was 2.79 %. As predicted by traditional taxonomy, sequence analyses demonstrated the close affinity of S. mexicana with S. hellwegeri. However, this also suggested the existence of cryptic species within S. mexicana, one of the stingless bees exploited for honey production in Mesoamerica. These results confirm the hypothesis that the DNA barcoding technique may at least differentiate stingless bee taxa accepted by current taxonomy.