Study of the colony-environment relationship in domestic bee populations (Apis mellifera L.) by implementing electronic remote monitoring systems

La polinización es la aportación principal de la abeja doméstica (Apis mellifera L.) a los ecosistemas terrestres, y además resulta fundamental para el éxito de muchos cultivos. Sin las abejas podría estar seriamente comprometida la viabilidad de muchas especies vegetales. Sin embargo, las poblaciones de abejas están sufriendo importantes pérdidas, decreciendo debido a diferentes factores no bien identificados, aunque el cambio climático ha sido propuesto como uno de ellos. Por tanto, entender cómo responden las abejas a los nuevos escenarios climáticos es esencial para hacerle frente, especialmente en las zonas bioclimáticas más sensibles, como es el área mediterránea. En este sentido, es necesario conseguir toda la información posible sobre cómo interactúan las abejas con las condiciones ambientales, y cómo son capaces de regular estas condiciones en el interior de la colmena, empleando además métodos lo menos intrusivos posibles, evitando así modificar las condiciones naturales y obtener datos más realistas. Con ese objetivo, hemos diseñado un sistema de monitorización remota, al que hemos denominado WBee, basado en la tecnología Waspmote, y diseñado como un modelo jerárquico a tres niveles: nodo inalámbrico, un servidor local, y un servidor para almacenar los datos en la nube. WBee es un sistema fácilmente adaptable en relación al número y tipo de sensores, al número de colmenas y a su distribución geográfica. WBee además almacena los datos en cada uno de los niveles por si se produjeran errores en la comunicación, disponiendo los nodos también con baterías de apoyo, lo que permite continuar recabando información aunque se produzca una caída del sistema eléctrico. Actualmente el sistema está dotado con sensores que le permiten monitorizar la temperatura y la humedad relativa de la colonia en tres puntos diferentes, así como el peso de la colmena. Todos los datos recogidos se pueden consultar a tiempo real con acceso a través de internet. Una vez implementado el sistema, apoyándonos en los datos obtenidos, hemos estudiado la relación de las abejas con el medio en tres situaciones: en la primera, monitorizamos las tres variables (peso, temperatura y humedad relativa) a lo largo de un mes en 20 colmenas, coincidiendo con una floración comercial de girasol. Esto nos ha permitido entender la evolución de las colonias durante una floración, registrar la producción de miel en las colmenas y estimar el momento óptimo para su extracción, además de verificar el correcto funcionamiento del sistema Wbee. En la segunda, se estudió la influencia de episodios de temperaturas extremas en las colmenas durante el periodo de floración en las campañas apícolas de 2016 y 2017. En este ensayo usamos los cambios en el peso de las colmenas como variable indicadora de la evolución de las colonias, y lo completamos con evaluaciones exhaustivas en tres momentos críticos (principio, mitad y final) de la floración en su conjunto, determinando la población de abejas adultas, cría, y reservas de polen y miel. Los resultados mostraron que la floración se redujo en tres semanas en 2017 en comparación con 2016, ya que las condiciones adversas afectaron significativamente a la evolución normal de las poblaciones de abejas y las reservas de polen y miel, incrementando el estrés alimenticio de las abejas. Esto también afectó al espectro polínico y a las características comerciales de la miel. En la tercera, se registraron los datos de peso, humedad y temperatura de 10 colmenas de abejas ibéricas durante los mismos dos años completos. Estos datos fueron usados para identificar los factores climáticos que potencialmente afectan al comportamiento regulatorio interno en las colmenas y el peso de las mismas. Sobre estos datos se realizó un análisis categórico de los componentes principales (CATPCA) que fue usado para determinar el número mínimo de los factores capaces de explicar el máximo porcentaje de la variabilidad registrada en los datos. A continuación, se usó una regresión categórica (CATREG) para seleccionar los factores que estaban relacionados linealmente con el peso, temperatura y humedad interna de las colmenas, con los que proponer ecuaciones de regresión específicas para abejas ibéricas. Los resultados obtenidos, especialmente aquellos relacionados con la humedad relativa, contrastan con los previamente publicados en otros estudios con abejas en el centro y norte de Europa, y pueden ayudar a planificar una apicultura más eficiente, así como a conocer el efecto del cambio climático en las abejas. Finalmente, los resultados no solo atañen a las abejas, pues el sistema puede ser una herramienta muy útil para estudiar lo que sucede en el medio, usando las colonias de abejas como bioindicadores.Pollination is the main contribution of the domestic bee (Apis mellifera L.) to terrestrial ecosystems, and it is also essential for the success of many crops. Without bees, the viability of many plant species could be seriously compromised. However, bee populations are suffering significant losses, and are decreasing due to different factors not well identified, although climate change has been proposed as one of them. Therefore, understanding how bees respond to new climate scenarios is essential to face it, especially in sensitive bioclimatic zones, such as the Mediterranean area. In this sense, it is necessary to obtain a large amount of information on how bees interact with environmental conditions, and how they are able to regulate these conditions inside the hive, also using the least intrusive methods possible, and avoiding modifying natural conditions and obtaining more realistic data. With this objective, we have designed a remote monitoring system, which we have called WBee, based on Waspmote technology, and designed as a hierarchical model at three levels: wireless node, a local data server, and a cloud data server. WBee is an easily adaptable system in relation to the number and type of sensors, the number of hives and their geographical distribution. WBee saves the data in each of the levels if there are failures in communication, also include a backup battery, which makes it possible to continue collecting data in the event of a power outage. Currently the system is equipped with sensors that allow it to monitor the temperature and relative humidity of the colony at three different points, as well as the weight of the hive. All the data collected can be consulted in real time with Access through the internet. Once the system was implemented, we have studied, based on the data obtained, the relationship of bees with the environment in three situations: in the first, we evaluated the three variables (weight, temperature and relative humidity) over a month in 20 hives, coinciding with a commercial sunflower flowering. This has allowed us to understand the evolution of the colonies during a flowering period, to record the production of honey in the hives and to estimate the optimal moment for its extraction, in addition to verifying the correct functioning of the Wbee system. In the second, the influence of episodes of extreme temperatures in the hives during the flowering period, in the 2016 and 2017 beekeeping sessions, was evaluated. In this study we use the changes in the weight of the hives as a reflection of the evolution of the colonies, and we complete it with exhaustive assessments at three critical moments (beginning, middle and end) of the flowering, determining the population of adult bees, brood, and pollen and honey reserves. The results showed that flowering was reduced by three weeks in 2017 compared to 2016, since the normal evolution of bee populations and pollen and honey reserves were significantly affected by adverse conditions, increasing the nutritional stress of the bees. This also affected the pollen spectrum and the commercial characteristics of honey. In the third, the weight, humidity and temperature data of 10 hives of Iberian bees were recorded during the same two full years. These data were used to identify climatic factors that potentially affect internal regulatory behavior and their weight in hives. On these data, a Categorical principal components analysis (CATPCA) was carried out, which was used to determine the minimum number of factors capable of explaining the maximum percentage of the variability recorded in the data. Next, a categorical regression (CATREG) was used to select the factors that were linearly related to hive internal humidity, temperature and weight to issue predictive regression equations in Iberian bees. The results obtained, especially those related to relative humidity, contrast with those previously published in other studies with bees in central and northern Europe, and can help to plan more efficient beekeeping, as well as to know the effect of climate change on the bees. Finally, the results do not only concern bees, since the system can be a useful tool to study what happens in the environment, using bee colonies as bioindicators

Regulation of Microclimatic Conditions inside Native Beehives and Its Relationship with Climate in Southern Spain

In this study, the Wbee Sensor System was used to record data from 10 Iberian beehives for two years in southern Spain. These data were used to identify potential conditioning climatic factors of the internal regulatory behavior of the hive and its weight. Categorical principal components analysis (CATPCA) was used to determine the minimum number of those factors able to capture the maximum percentage of variability in the data recorded. Then, categorical regression (CATREG) was used to select the factors that were linearly related to hive internal humidity, temperature and weight to issue predictive regression equations in Iberian bees. Average relative humidity values of 51.7% ± 10.4 and 54.2% ± 11.7 were reported for humidity in the brood nest and in the food area, while average temperatures were 34.3 °C ± 1.5 in the brood nest and 29.9 °C ± 5.8 in the food area. Average beehive weight was 38.2 kg ± 13.6. Some of our data, especially those related to humidity, contrast with previously published results for other studies about bees from Central and northern Europe. Conclusively, certain combinations of climatic factors may condition within hive humidity, temperature and hive weight. Southern Iberian honeybees’ brood nest humidity regulatory capacity could be lower than brood nest thermoregulatory capacity, maintaining values close to 34 °C, even in dry conditions

Honey Bee Colonies Remote Monitoring System

Bees are very important for terrestrial ecosystems and, above all, for the subsistence of many crops, due to their ability to pollinate flowers. Currently, the honey bee populations are decreasing due to colony collapse disorder (CCD). The reasons for CCD are not fully known, and as a result, it is essential to obtain all possible information on the environmental conditions surrounding the beehives. On the other hand, it is important to carry out such information gathering as non-intrusively as possible to avoid modifying the bees’ work conditions and to obtain more reliable data. We designed a wireless-sensor networks meet these requirements. We designed a remote monitoring system (called WBee) based on a hierarchical three-level model formed by the wireless node, a local data server, and a cloud data server. WBee is a low-cost, fully scalable, easily deployable system with regard to the number and types of sensors and the number of hives and their geographical distribution. WBee saves the data in each of the levels if there are failures in communication. In addition, the nodes include a backup battery, which allows for further data acquisition and storage in the event of a power outage. Unlike other systems that monitor a single point of a hive, the system we present monitors and stores the temperature and relative humidity of the beehive in three different spots. Additionally, the hive is continuously weighed on a weighing scale. Real-time weight measurement is an innovation in wireless beehive—monitoring systems. We designed an adaptation board to facilitate the connection of the sensors to the node. Through the Internet, researchers and beekeepers can access the cloud data server to find out the condition of their hives in real time

Impact of Varroa destructor and associated pathologies on the colony collapse disorder affecting honey bees

11 Pág. Instituto Nacional de Investigación y Tecnología AgroalimentariaVarroa mite is the major threat to the western honey bee, Apis mellifera, and the cause of significant economic losses in the apiculture industry. Varroa destructor feeds on brood and adult bees being responsible for vectoring virus infections and other diseases. This study analyses the role of Varroa and other associated pathogens, such as viruses or the fungus Nosema ceranae, and their relationships regarding the viability of the bee colony. It has been carried out during one beekeeping season, with the subspecies A. m. iberiensis, commonly used in the apiculture industry of Spain. Our study shows a significant relationship between the presence of Varroa destructor and viral infection by deformed wing virus and acute bee paralysis virus. Nosema ceranae behaved as an opportunistic pathogen. In addition, this study explored a potential naturally occurring subset of peptides, responsible for the humoral immunity of the bees. The expression of the antimicrobial peptides abaecin and melittin showed a significant relationship with the levels of Varroa mite and the deformed wing virus.The authors would like to thank the European Union European Regional Development Fund FEDER 2014–2020, the National Institute for Agricultural and Food Research and Technology (INIA) of Spain, and the Projects Ref. RTA2013-00042-C10-01/07 and RTA2017-00058-C04-01/03 for their financial support.Peer reviewe

A three-year large scale study on the risk of honey bee colony exposure to blooming sunflowers grown from seeds treated with thiamethoxam and clothianidin neonicotinoids

9 Pág.Despite the restriction of the use of neonicotinoids in the EU, including thiamethoxam and clothianidin, the debate over their risk on honey bees has not been fully settled. This study presents results of a three-year study working with 180 honey bee colonies in ten replicates. Colonies were sorted into three treatments (60 colonies per treatment) exposed to sunflower blooms grown from seeds treated with thiamethoxam, clothianidin and a non-treated control. Each colony was assessed at six moments: one before to exposition to sunflower, two during the exposition (short-time risk), two after exposition (medium-time risk) and one after wintering (long-time risk). The health and development of the colonies were assessed by monitoring adult bee population, brood development, status of the queen, food reserves and survival. No significant difference among treatments when raw data was considered. However, when evolution from initial status of the colony was evaluated, a significant difference was observed from the first week of exposure to sunflower blooms. In this period, the number of adult bees and the amount of brood were slightly lower in the bee hives exposed to neonicotinoids, although such differences disappeared in subsequent evaluations. The concentration of residues in samples of beebread and adult bees was at the level of ng·g-1. Magnitude of the effect of the treatment factor on the variability of colony health and development related parameters was low. The most important factor was the hive, followed by the replicate and year, and to a lesser extent the initial strength of the colonies.This study has been carried out in line with the framework of the project RTA2013-00042-C10.Peer reviewe