Although honey bees are the most frequently studied social insects due to their ecological and economic importance (Winston, 1987; Martin, 2001), a set of factors still not well understood has been affecting these arthropods in an increasing number of countries. Various organisms can parasitize honey bees in the immature or adult phase, possibly leading to collapse of the colony depending on the level of virulence (Bailey & Ball 1991; Ellis & Munn, 2005). There have been many reports of colony collapse in the Northern Hemisphere in recent years, prompting strong concern in the scientific community, particularly due to the importance

The hypopharyngeal gland (HG), along with the mandibular gland from Apis mellifera workers plays a fundamental role on the development of the hive. The protein based substances produced by the hypopharyngeal and mandibular glands are two important component of the royal jelly, which is responsible for caste differentiation and used to feed larvae, drones and the queen. Several factors may alter the physiology of glandular structures in honeybees and consequently their role within the beehive, and one of the most important factors is their nutritional status. However, few studies have evaluated the development of HG against different diets on Africanized honeybees. Our experiment was composed of four diets (treatments) offered to different groups of workers: (T1) honey, (T2) honey + soybean extract, (T3) honey + pollen and (T4) sucrose solution. The development of the glands was evaluated in two periods: 7 and 10 days of exposure to the diet types. According to the results, an interference of the diet on the acini area of the HG was observed. Bees that were fed with the sucrose solution or soybean extract presented the smallest acini areas as compared to the other treatments. The time of exposure to the different types of diets also had an effect on acini areas. Worker bees fed with honey and soybean extract for 10 days presented smaller acini areas when compared to bees dissected at the 7th day of exposure to those same diet types. Nevertheless, we also observed that factors other than just nutrition are important to the full development of the HG, such as the stimulus promoted by the young breeds.

Abstract. The Africanized honey bees (AHB) are known by the high productivity and tolerance against pathogens and parasites such Varroa destructor. Besides these beneficial characteristics, the AHB are considered highly defensive and generally urges caution in management. However, little is known about the behavioral aspects of AHB in Brazilian beekeeping. In this context, our objectives were to evaluate the repertoire of defensive behavior (DB) in AHB emphasizing the relevance of environmental and visual stimuli, as well as the aggressiveness gradient among Brazilian colonies. The aspects related to defensive behavior were measured by Stort method with some adaptations. We found differences between colonies in the speed of first attack and attack intensity (p<0.05%), although the DB patterns were not affected by temperature and period of evaluations. All attacks began in the black part of sphere target; however after the first sting both parts (black and white) were attacked. This fact indicates that even the visual clues have a relevant role in colony defense; chemical signs (alarm pheromones) maintain the target and act in attack increase. We also identified a great variation in defensive pattern among the studied colonies that was indeed expected due to high genetic variability present in AHB. The DB evaluation plays an important role in colony selection and genetic improvement based on beneficial characters such as high honey production and low aggressiveness during management.Repertório do Comportamento Defensivo em Apis mellifera L. africanizada (Hymenoptera: Apidae): Variações nos Padrões Defensivos e Influência de Estímulos VisuaisResumo. As abelhas africanizadas (AHB) são conhecidas por sua alta produtividade e tolerância a patógenos e parasitas como o ácaro Varroa destructor. Em contraste às características vantajosas, as AHB são consideradas altamente defensivas necessitando de certos cuidados em seu manejo. Entretanto, poucos estudos relatam características específicas sobre os padrões de comportamento de AHB na apicultura brasileira. Nesse contexto, o objetivo do trabalho foi avaliar o repertório do comportamento defensivo (DB) em AHB, identificando a importância de condições climáticas e estímulos visuais nesta característica, bem como gradiente de agressividade dentre as colônias. Os aspectos relacionados ao comportamento defensivo foram avaliados pelo método de Stort com adaptações. Foram encontradas diferenças entre as colônias em relação à velocidade do primeiro ataque e intensidade de ataque (p<0.05%), por outro lado os padrões de DB não foram afetados pela variação de temperatura durante os períodos de avaliação. Todos os ataques se iniciaram pela parte preta da esfera alvo, contudo após o primeiro ataque ambos os lados (preto e branco) sofreram ataques. Tal fato indica que embora as pistas visuais possuam um papel relavente na defesa das colônias, sinais químicos (feromônios de alarme) atuam na manutenção e aumento do possível alvo. Pôde-se também identificar uma grande variação nos padrões defensivos dentre as colônias estudadas, fator esperado devido a grande variabilidade genética presente em AHB. Por sua vez, a avaliação do DB possui um importante papel na seleção e melhoramento de colônias visando à seleção de características benéficas como alta produtividade de mel e baixa agressividade durante o manejo.