RESUMO Esta revisão tem por objetivo agrupar os dados referentes ao estudo das plantas tóxicas para abelhas. São relacionados os mais importantes artigos publicados sobre o assunto, principalmente os de autores brasileiros, confirmando os efeitos tóxicos do pólen ou néctar sobre estes insetos. As informações sobre as estruturas químicas de substâncias isoladas das diversas partes das plantas e sua atividade biológica, têm auxiliado muito na identificação dos mecanismos da intoxicação das abelhas por estas plantas.

ABSTRACT This review cover's some data from studies about toxic plants. There are plants that produce toxic pollen or nectar, and these plants were used in laboratory bioassays, confirming toxic effects against bees. Most of information on chemical structures of toxins and their effects on insects and mammals has been obtained from research. Such knowledge can help us to discover the chemical nature of bee poisoning by these plants.

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.

In this paper we proposed to estimate the heritability of seven morphological characters that compose the sting apparatus of the Africanized honeybee workers. An experimental design to estimate genetic parameters was based on the method developed by Oldroyd and Moran(9). This method was modified to eliminate within-colony environmental effects associated with the additive genetic variance. The estimated h<img SRC="http:/img/fbpe/jvat/v3n2/image1800.gif"> values ranged from 0.17 ± 0.11 (maximum width of bulb of sting stylet and height of the valve of right lancet) to 0.74 ± 0.30 (length of the lancet).

A comparison among the profiles of molecular exclusion chromatography in Sephadex G 100 column of venoms from Apis mellifera adansonii and Africanized honeybees revealed unique peaks which might be used to identify these populations. The venoms from hybrid populations resulting from the reciprocal mating of Apis mellifera adansonii and Africanized honeybees presented unique peaks, probably resulting from a synergistic effect between the parental genomes. The occurrence of characteristic peaks in venoms of hybrid populations might be used to identify these populations as well as to distinguish them from their parents.