viernes, 6 de julio de 2018

Publicaciones Luis Medina Medina

Memorias VI Congreso Mesoamericano sobre Abejas Nativas
Actividad Antimicrobiana y Origen Botánico en Mieles de Melipona beecheii,
Scaptotrigona pectoralis
y Apis mellifera del Estado de Yucatán
Catzín Ventura Gloria A., Alfaro Bates Rita, Medina Medina Luis A., Delgado Herrera María A.
Se analizaron palinológicamente mieles producidas por tres especies de abejas
(A. mellifera, M. beecheii y S. pectoralis) que exhibieron actividad inhibitoria (AA)sobre cuatro bacterias patógenas (Staphylococcus aureus, Streptococcus agalactiae, Escherichia coli y Pseudomona aeruginosa). Las mieles fueron colectadas en el estado de Yucatán (México), durante los meses de Octubre del 2007 a Marzo del 2008. En general, las mieles de las abejas nativas mostraron mayor AA. La bacteria que resultó inhibida por la miel de las 3 especies de abejas fue S. aureus, mientras que E. coli fue la que mostró mayor resistencia. Las mieles de A. mellifera y M. beecheii clasificadas como uniflorales, presentaron AA contra un mayor número de bacterias, mientras que las mieles de S. pectoralis mostraron AA tanto en las mieles uniflorales como multiflorales. Se identificaron un total de 16 tipos polínicos pertenecientes a 9 familias, en la miel colectada durante este período para las tres especies de abejas. Los resultados indican que las mieles provenientes de las dos especies de abejas nativas presentaron una mayor AA, en comparación con la registrada para A. mellifera. La variabilidad intra-especifica de la actividad antimicrobiana de las mieles estudiadas puede ser debido a su origen floral.
Palabras clave: Actividad antimicrobiana, abejas nativas, miel, origen botánico,

Medina, M.L.; Martin, S.J. (1999) A comparative study of Varroa jacobsoni reproduction in worker cells of honey bees (Apis mellifera) in England and Africanized bees in Yucatan, Mexico. Experimental and Applied Acarology 23: 659-667.
The aim of this study was to investigate an underlying mechanism of the apparent tolerance of Africanized honey bees (AHB) to Varroa jacobsoni mites in Mexico. This was achieved by conducting the first detailed study into the mites’ reproductive biology in AHB worker cells. The data was then compared directly with a similar study previously carried out on European honey bees (EHB) in the UK. A total of 1071 singly infested AHB worker cells were analyzed and compared with the data from 908 singly infested EHB worker cells. There was no significant difference between the number of mother mites dying in the cells (AHB=2.0%, EH=1.8%); the mean number of eggs laid per mite (AHB= 4.86, EHB= 4.93); the number of mites producing no offspring (AHB= 12%, EHB= 9%); and developmental times of the offspring in worker cells of AHB and EHB. However, there was a major difference between the percentage of mother mites producing viable adult female offspring (AHB= 40%, EHB= 75%). This was caused by the increased rate of mite offspring mortality suffered by the first (male) and second (female) offspring in AHB worker cells. Therefore, only an average of 0.7 viable adult female offspring are produced per mite in AHB, compared to 1.0 in EHB.

Medina, M.L.; Martin, S.J.; Espinosa-Montaño, L; Ratnieks, F.L.W. (2002) Reproduction of Varroa destructor in worker brood of Africanised honey bees (Apis mellifera). Experimental and Applied Acarology 27: 79-88.
Reproduction and population growth of Varroa destructor was studied in ten naturally infested, Africanized honeybee (AHB) (Apis mellifera) colonies in Yucatan, Mexico. Between February 1997 and January 1998 monthly records of the amount of pollen, honey, sealed worker and drone brood were recorded. In addition, mite infestation levels of adult bees and worker brood and the fecundity of the mites reproducing in worker cells were determined. The mean number of sealed worker brood cells (10,070 ± 1,790) remained fairly constant over the experimental period in each colony. However, the presence and amount of sealed drone brood was very variable. One colony had drone brood for 10 months and another for only 1 month. Both the mean infestation level of worker brood (18.1 ± 8.4%) and adult bees (3.5 ± 1.3%) remained fairly constant over the study period and did not increase rapidly as is normally observed in European honey bees. In fact, the estimated mean number of mites fell from 3,500 in February 1997 to 2,380 in January 1998. In May 2000 the mean mite population in the study colonies was still only 1,821 mites. The fertility level of mites in this study was much higher (83–96%) than in AHB in Brazil(25–57%), and similar to that found in EHB (76–94%). Mite fertility remained high throughout the entire study and was not influenced by the amount of pollen, honey or worker brood in the colonies.

Correa-Marques, M.H.; Medina, M.L.; Martin, S.J.; De Jong, D. (2003) Comparing data on the reproduction of Varroa. Genetics and Molecular Research 2: 1-6.
Varroa destructor reproductive success is considered an important character for determining the resistance of honey bees to this mite parasite. However, most of the published data are not comparable due to the different methods of ascertaining and reporting reproduction. A recently published technique that involves reconstructing mite families in older worker brood gives repeatable and reliable parameters. This methodology was used to compare various categories of reproduction of approximately 1,000 V. destructor females in each of three studies on Africanized bees in Brazil and Mexico and European bees in England. The most objective and useful measure was the determination of the number of viable females per female that had invaded the worker brood in singly infested cells, which was denominated the “effective reproduction rate”. Viable females are those that can reach the adult stage and have a mate available. The effective reproduction rate in worker brood was 0.64, 0.73 and 1.01 in Brazil, Mexico and England, respectively. Standardization of reproduction determination techniques would make published data comparable and much more useful.

Martin, S.J.; Medina, L.M. (2004) Africanized honeybees possess unique tolerance to Varroa mites. Trends in Parasitology. 20(3): 112-114.
Varroa destructor is an ectoparasitic mite of the adult honeybee, which parasitizes the bee brood. This mite has killed millions of honeybee Apis mellifera colonies, worldwide, eliminating wild populations throughout Europe and North America, and resulting in the loss of billions of dollars in agricultural production. The Africanized honeybee (AHB) has a unique tolerance to V. destructor that is not present in the A. mellifera European honeybee (EHB), from which the AHB hybrid was derived. This unexpected tolerance mechanism provides a valuable insight into the evolution of host–parasite interactions….

May-Itzá, W. de J.; Medina, M.L.; Marrufo, O.J. (2007) Effectiveness of a thymol based gel for the control of Varroa destructor mite that infests Apis mellifera honey bee colonies, under tropical conditions in Yucatan, Mexico. Veterinaria México 38 (1): 1-8.
The effectiveness of a thymol based gel (12.5 g of thymol in 50 g of gel) for controlling Varroa destructor in commercial honey bee (Apis mellifera) colonies under tropical conditions was evaluated. Three groups of honey bee colonies were used, the first group received one tray containing thymol gel (G1), the second group received two trays with thymol gel (G2) and the third group (control) received no treatment (G3).The application of the gels was repeated twice with two weeks between treatments. In total G1 received 2 trays and G2 received 4 trays of thymol gels, thus the honey bee colonies and the mites were exposed to the thymol gels during 30 days. The mite infestation levels in adult bees and capped brood were registered before and after the application of the treatments in order to evaluate the effectiveness of the thymol based gels. The effectiveness of the treatments estimated for adult bees was 97% and 93% for G1 y G2, respectively, and in the capped brood the effectiveness was 94% and 95% for both groups respectively. The results show that the application of one thymol gel (G1) tray with a second application in a 15 days interval (total of two trays) can eliminate ≈95% of the mites in honey bee colonies under tropical conditions and thus can be used as an alternative method for the apiculturist of this region to control this parasite.

Martínez Puc, J.F.; Medina, M.L. (2011) Evaluation of the resistance of the mite Varroa destructor to the fluvalinate in colonies of honey bees (Apis mellifera) in Yucatan, Mexico. Revista Mexicana de Ciencias Pecuarias 2(1): 93-99.
The constant application of pyrethroids for controlling the mite Varroa destructor has caused the appearance of populations of resistant mites to this product in several parts of the world. With the purpose of detecting the possible existence of populations of resistant mites to the fluvalinate in the State of Yucatan, one of the main honey producer states in Mexico, 12 samples were gathered from each apiary, selecting four apiaries where fluvalinate was used in constant way for the control of V. destructor during five years, and a similar quantity of samples coming from apiaries where methods of alternative control have been used during a similar time. To determine from the mites the percentage of mortality to the fluvalinate, they were exposed to a piece of 2.5 x 1.0 cm from Apistan® at 10%, during 24 h. The percentage of mortality of varroas coming from apiaries treated in a constant way with fluvalinate was of 83.6 ± 0.51 %, lower to the percentage of mortality obtained in apiaries that only received alternative treatment which was of 93.9 ± 1.98 %, existing differences between both groups (t=-3.93, P=0.01, gl= 46). This means a reduction in the percentage of mortality obtained with the fluvalinate. However, this reduction still does not reach the necessary levels that can define the presence of resistant mites, being important to change the practices that seem to reduce the levels of infestation of V. destructor. Then it is advisable the application of methods of alternative control which don’t cause the resistance development in the populations of mites.

miércoles, 30 de mayo de 2018

Tesista de Licenciatura en Biología: Vianey E. Poot Báez. 

Título de tesis: Efecto de la fluctuación de temperatura en el tamaño corporal de obreras de Apis mellifera L. (Hymenoptera:Apidae) en épocas de calor en Yucatán, México.

Fecha de examen profesional: 29 de Mayo de 2018

Asesor: Dr. José Javier G. Quezada Euán

jueves, 24 de mayo de 2018


Nuevo libro en prensa, Abejas sin aguijón de México. Versión en español publicada por la UADY (aprox 300 págs y 100  láminas en color).  Publicación tentativa, octubre 2018

martes, 24 de abril de 2018

Medina R.G., Paxton R.J., De Luna E., Fleites-Ayil F., Medina-Medina L.A., Quezada-Euán J.J.G. (2018) Developmental stability, age at onset of foraging and longevity of Africanized honey bees (Apis mellifera L.) under heat stress (Hymenoptera: Apidae). Journal of Thermal Biology 74: 214-225.


Beekeeping with the western honey bee (Apis mellifera) is important in tropical regions but scant information is available on the possible consequences of global warming for tropical beekeeping. We evaluated the effect of heat stress on developmental stability, the age at onset of foraging (AOF) and longevity in Africanized honey bees (AHBs) in the Yucatan Peninsula of Mexico, one of the main honey producing areas in the Neotropics, where high temperatures occur in spring and summer. To do so, we reared worker AHB pupae under a fluctuating temperature regime, simulating current tropical heatwaves, with a high temperature peak of 40.0 °C for 1 h daily across six days, and compared them to control pupae reared at stable temperatures of 34.0–35.5 °C. Heat stress did not markedly affect overall body size, though the forewing of heat-stressed bees was slightly shorter than controls. However, bees reared under heat stress showed significantly greater fluctuating asymmetry (FA) in forewing shape. Heat stress also decreased AOF and reduced longevity. Our results show that changes occur in the phenotype and behavior of honey bees under heat stress, with potential consequences for colony fitness.

jueves, 20 de julio de 2017

Fin de semestre enero-julio 2017

Estudiantes Verano de la Investigación 2017

Br. Sergei Paolo Arévalo Campos

Institucion procedencia:   Universidad Juárez Autónoma de Tabasco
Periodo:  19 junio al 11 de agosto .  

Proyecto: Niveles de infestación de Nosema sp. en obreras de Apis mellifera.
Asesor: Dr William May Itzá