Artículos Científicos

URI permanente para esta colecciónhttp://10.0.96.45:4000/handle/11056/17242

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Behavior of varroa mites in worker brood cells of Africanized honey bees
(Experimental and Applied Acarology/ Springer, 2019-04-19) Fallas, Natalia; Zamora Fallas, Luis Gabriel; Van Veen, Johan; Sánchez Chaves, Luis; Calderon, Rafael
El ácaro ectoparásito Varroa destructor es actualmente la plaga más importante de la abeja melífera, Apis mellifera. Dado que la reproducción del ácaro tiene lugar dentro de la celda sellada, la observación directa de la actividad de Varroa en el interior de la celda resulta difícil. Para analizar el comportamiento de los ácaros varroa en las crías de obreras de abejas melíferas africanizadas se utilizó un método de observación por vídeo con celdas transparentes de poliestirol que contenían crías infestadas. Se grabó cómo los ácaros se alimentan de la larva y la pupa, construyen un lugar de acumulación fecal y cómo la larva de abeja realiza algunos movimientos longitudinales alrededor de la celda. La actividad alimentaria del ácaro fundador varía en el transcurso del ciclo. En la prepupa se observó que los ácaros se alimentaban con frecuencia (0,3 ± 0,2 episodios h-1) durante un periodo de 8,7 ± 8,4 min h-1 y no había preferencia por un segmento específico como lugar de alimentación. Por el contrario, durante la fase de pupa los ácaros se alimentaron con menor frecuencia (0,1 ± 0,1 episodios h-1) durante un periodo de 6,2 ± 4,0 min h-1 y casi siempre en un sitio concreto (92,4%). En las pupas, el 83,7% de la alimentación tuvo lugar en el 2º segmento abdominal (n = 92), y sólo se encontraron unas pocas perforaciones en el tórax. Varroa muestra preferencia por defecar en la parte posterior de la celda (ápice de la celda), cerca de la zona anal de las abejas.Encontramos una alta correlación entre la posición del sitio de alimentación en la pupa y la posición de la acumulación fecal en la pared celular. La mayoría de las células infestadas tienen un solo lugar de acumulación fecal y éste fue el sitio de descanso favorito del ácaro, donde pasó 24,3 ± 3,9 min h-1. Se observaron desplazamientos longitudinales en el 28,0% (n = 25) de las larvas de abeja analizadas. Los movimientos de giro alrededor de la celda, desde abajo hacia arriba, fueron realizados por estas larvas, principalmente durante el segundo día (47,7 ± 22,5 min h-1), justo antes de la pupación, con un tiempo total de 874,9 ± 262,2 min día-1 (n = 7 individuos). Estos resultados en crías de obreras de abejas africanizadas demuestran adaptaciones de los ácaros Varroa para parasitar a la abeja en desarrollo dentro de las celdas de cría tapadas.
Nosemosis in africanized honey bee colonies in tropical conditions of Costa Rica: Nosema apis or Nosema cerenae
(Revista de Ciencias Veterinarias, UNA, 2021-06-17) Calderón, Rafael A.; Sánchez, Luis A
The presence of nosemosis in Africanized honey bees in Costa Rica was studied. A total of 75 samples of adult bees from different country regions were selected for molecular diagnosis of nosemosis. Prior to PCR tests, Nosema spp. spores were morphologically identified in most of the bee samples using a light microscopy at 40x magnification. According to molecular analyses, most of the bee samples were found to be infected with Nosema ceranae. However, colonies showed no clinical signs of infection at any time during the sampling period, none of them being infected with Nosema apis. Surprisingly, 29.3% of the bee samples tested PCR negative to nosemosis. The origin of the bee samples collected from apiaries located in four of the seven provinces of Costa Rica showed the microsporidium is widely spread throughout the main beekeeping areas of the country. The pathological consequences of N. ceranae in Africanized honey bee colonies have not been well determined. Because of reports of honey bee colony losses in Europe related to microsporidian infections, the virulence of N. ceranae in Africanized honey bees needs to be studied.
Presence of Nosema ceranae in Africanized honey bee colonies in Costa Rica
(Universidad Nacional, Costa Rica, 2015-03-25) Sánchez Chaves, Luis; Calderón, Rafael; Yanez, Orlando; Fallas, Natalia
Nosemosis is a severe disease caused by the microsporidian Nosema sp. affecting adult honey bees (Apis mellifera) (Bailey and Ball, 1991). Nosema spores infect the epithelial layer of the ventriculus and midgut of adult bees, causing digestive disorders and shortening the life span of bees, with a resulting decrease in bee population (Ritter, 2001). So far only two microsporidian parasites have been described in honey bees: N. apis and N. ceranae. Nosema apis was the first described microsporidian in honey bees (Zander, 1909)
Reproductive biology of Varroa destructor in Africanized honey bees (Apis mellifera)
(Experimental and applied Acaralogy Springer, 2009-10-23) Sánchez Chaves, Luis; Sommeijer, Marinus; Calderón, Rafael; Van Veen, Johan Wilhelm
Since its first contact with Apis mellifera, the population dynamics of the parasitic mite Varroa destructor varies from one region to another. In many regions of the world, apiculture has come to depend on the use of acaricides, because of the extensive damage caused by varroa to bee colonies. At present, the mite is considered to contribute to the recent decline of honey bee colonies in North America and Europe. Because in tropical climates worker brood rearing and varroa reproduction occurs all year round, it could be expected that here the impact of the parasite will be even more devastating. Yet, this has not been the case in tropical areas of South America. In Brazil, varroa was introduced more than 30 years ago and got established at low levels of infestation, without causing apparent damage to apiculture with Africanized honey bees (AHB). The tolerance of AHB to varroa is apparently attributable, at least in part, to resistance in the bees. The low fertility of this parasite in Africanized worker brood and the grooming and hygienic behavior of the bees are referred as important factors in keeping mite infestation low in the colonies. It has also been suggested that the type of mite influences the level of tolerance in a honey bee population. The Korea haplotype is predominant in unbalanced host-parasite systems, as exist in Europe, whereas in stable systems, as in Brazil, the Japan haplotype used to predominate. However, the patterns of varroa genetic variation have changed in Brazil. All recently sampled mites were of the Korea haplotype, regardless whether the mites had reproduced or not. The fertile mites on AHB in Brazil significantly increased from 56% in the 1980s to 86% in recent years. Nevertheless, despite the increased fertility, no increase in mite infestation rates in the colonies has been detected so far. A comprehensive literature review of varroa reproduction data, focusing on fertility and production of viable female mites, was conducted to provide insight into the Africanized bee host-parasite relationship.

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Examinando Artículos Científicos por Materia "AFRICANIZED HONEY BEES"