May-Itzá W. de J., Medina LM. (2019).  Effectiveness of the smoke of fruits of Guazuma ulmifolia (Sterculiaceae) and vapors of Thymol for control of Varroa destructor infesting Africanized bees. Rev Mex Cienc Pecu.  10(3):778-788.

 Abstract:

The mite Varroa destructor is a scourge in honey bee colonies worldwide. Conventional chemical-based control treatments can contaminate colony products and cause resistance in the parasite. Plant-source compounds are promising alternatives. The effectiveness of smoke from dried Guazuma ulmifolia fruit and vapors from thymol crystals was evaluated in control of V. destructor in colonies of Africanized bees (Apis mellifera) in Yucatan, Mexico. Three treatments were used during a three-week experimental period. In Group 1, colonies were administered five to eight puffs of smoke from dried G. ulmifolia fruits twice a week. In Group 2, they were administered 4-8 g of thymol crystals once a week. Group 3 was a control and received no treatment. Collections of 200 to 300 adult bees from each colony were done prior to treatment (day 0) and after treatment at 7, 14 and 21 d. These were processed to quantify colony infestation levels and treatment efficacy. Overall V. destructor infestation levels in adult bees decreased in all three groups after 21 d, with differences between treatments. Levels were lowest in Group 2, followed by Group 1 and the control. Efficacy at the end of the treatments was 41 % in Group 1 and 69% in Group 2. Compared to the control, application of thymol crystals provided the most effective alternative control method against V. destructor. However, regular application of G. ulmifolia fruit smoke also reduced mite infestation levels, and this resource has the advantage of being locally available.

May-Itzá, W de J., Peña, W.L., De la Rúa, P., Quezada-Euán J.J.G. (2019).  A genetic and morphological survey to trace the origin of Melipona beecheii (Apidae: Meliponini) from Cuba. Apidologie  50, pages859–870  https://doi.org/10.1007/s13592-019-00696-7

Abstract

The stingless bee Melipona beecheii is extensively distributed across Mexico and Central America and the only Melipona found in the Greater Antilles. The aim of this work was to establish possible continental affinities of M. beecheii from the Antilles. We compared populations from the main island (Cuba) with two clearly separated genetic lineages of M. beecheii on mainland, namely the Yucatán peninsula (Mexico) and Costa Rica. We used morphometrics, the degree of cephalic maculation, and microsatellite variation. Results indicate a greater morphological and genetic similarity between populations from Cuba and the Yucatán peninsula with respect to those of Costa Rica. Based on our findings, we conclude that the origin of M. beecheii from Cuba is more likely the Yucatán peninsula (Mexico). We found evidence that isolation has not been large enough to result in a new genetic lineage.

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Friedel Anna, Lattorf H. Michael G., Quezada-Euán J. Javier. G., Boff Samuel (2020) Shared reproduction and sex ratio adjustment to clutch size in a socially polymorphic orchid bee. Ethology 126: 88-96. https://doi.org/10.1111/eth.12963

Abstract

 Nests of the primitively eusocial orchid bee Euglossa viridissima are generally founded by a solitary female but can be reactivated by female offspring, in the presence or absence of the mother. The population therefore exists of solitary and social nests that co‐occur in an area. A female can stay as a subordinate helper under a dominant female or disperse to become a solitary foundress. Yet, the costs and benefits of the different social phenotypes are so far little understood. Here, we compared solitary and social nests of orchid bees. We used offspring of solitary and social nests to calculate offspring sex ratio, and applied molecular markers to calculate intranidal relatedness, infer maternity and test whether sociality may have a genetic component. We found that social nests had on average more brood than solitary nests. The overall sex ratio in the population did not differ from 1:1. However, social nests tended to produce a split sex ratio with some nests producing mainly males and others mainly female offspring. Regardless of social phenotype, the number of offspring was correlated with the sex ratio, with smaller nests having a more female‐biased offspring. In social nests, not all offspring resulted from a single‐mated mother, which was also the case for some solitary nests. This suggests shared reproduction in social nests and may be an indication that intraspecific parasitism and nest takeover are not uncommon. Structure analyses did not reveal different genetic background of the two social phenotypes. Our results suggest that there is no clear benefit that favours one of the two social phenotypes over the other and that the population is kept at balance in terms of sex ratio.

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