Histological aspects and protein content of Apis mellifera L. Worker venom glands: the effect of electrical shocks in summer and winter

Abstract

This paper analyzes the summer and winter total protein content of 7, 14, 21, 28, 35, and 40-day old Apis mellifera L. worker venom glands before (control) and 24 and 96 hours after applying electrical shocks for venom extraction (experimental). During venom extraction, 7-day old workers responded more slowly and weakly to electrical shocks. This response intensifies with age, so that the workers approaching 20 days old respond faster and more aggressively to the shocks. Statistical analysis, using the non-parametric Wilcoxon and Kruskall-Wallis tests and complemented by the Jonckheere test, showed that the protein content varied from one age to another in the experimental group, which was well distinguishable from the values in the control Group in summer and winter. Summer values at all ages were always higher than those detected in winter in both groups. This variation seems to indicate the occurrence of more than one winter glandular development cycle. Histological studies showed secretion in the lumen of the control Group secretory tubes and reservoirs. The experimental group only showed vestigial secretion in the collapsed reservoirs at all ages, except at 7 days. These workers, which reacted less efficiently to electrical shocks, showed secretion in the lumen, reservoir, and tubes, even after the application of electrical shocks. During the 96 hours following the electrical shocks, a slight protein replacement was seen at some ages. This, although higher in summer than in winter, was much lower than the level detected in the control group at all ages. The significantly lower values were frequent in the older workers 96 hours after extraction and could reflect reabsorption or degradation of proteins from glandular secretion due to aging. Our results show that venom extraction is more productive in summer using older workers. However, their capacity of replacing protein eliminated during stinging of the substrate, in response to shocks is shown to be low, as demonstrated for other analyzed bees

Cytochemical Studies of the Nuclei of the Venom Glands' Cells of Apis mellifera (Hymenoptera, Apidae)

“…Such modifications correspond to the loss of metachromasy and to the diminution of the nuclear size as well as the lower visibility, definition, and number of the nucleoli. Therefore, this work confirms the morphological results we obtained [1], which established that the degeneration process of the venom gland commences at the proximal region at the age of 40 days, thus contradicting the propositions made by other authors who suggested that this process starts at the distal glandular region and ends in the proximal region [7]. It was also shown in this study that there is a differential metabolic activity between the nuclei of the distal and proximal regions of workers with the same age, with the ones in the distal region being more active than in the proximal region at both 14 and 40 days of age.…”

Evaluación de dos frecuencias de colecta de apitoxina extraída de colmenas de Apis mellifera L. durante la época estival en la Región de La Araucanía

“…Además, el contenido de veneno también varía entre temporadas (invierno y verano) y con la edad de las abejas, ya que Abreu et al (2000) reportaron que durante la extracción de veneno las abejas jóvenes (siete días de edad) responden más lentamente a las descargas eléctricas, intensificando su respuesta a medida que avanza su edad, ya que éstas deben salir en busca de alimento y están más expuestas a peligros reales y responden con mayor rapidez a los estímulos del medio ambiente, por lo que producen una mayor cantidad de veneno. Además, Gauldie et al (1978) señalan que la composición del veneno varía con el tiempo, la época del año, la dieta y el método de recolección.…”

Alterations induced by the juvenile hormone in glandular cells of the Apis mellifera venom gland: Applications on newly emerged workers (Hymenoptera, Apidae)

“…This cycle reaches its highest secretory activity around the 16th day of the bee's adult life . Immediately afterwards, the gland enters the degeneration process (Cruz-Landim and Kitajima, 1966;Abreu et al, 2000), characterized by a reduction in the cells' height, vacuolization, disintegration of the cytoplasm, and increase in the staining capacity of the nuclei, which become pycnotic and irregular Abreu et al, 2000). This degeneration process coincides with the beginning of the foraging activity for the worker and with the increase in the titer of juvenile hormone circulating in the haemolymph.…”