Africanized honeybee stings: how to treat them

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Vasoconstrictor effect of Africanized honeybee (Apis mellifera L.) venom on rat aorta

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Hyperalgesic and edematogenic effects of Secapin-2, a peptide isolated from Africanized honeybee (Apis mellifera) venom

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

HISTORICAL PERSPECTIVE and HUMAN CONSEQUENCES of AFRICANIZED BEE STINGS IN THE AMERICAS

In 1956, Africanized bees began to spread in the American continent from southern Brazil, where original African bees mated with European bees. A few years later, in 1990, these Africanized bees reached the United States and were found in Texas. Currently, these hybrid bees are found in several North American states and will probably reach the Canadian border in the future. Although the presence of Africanized bees had produced positive effects on Brazilian economy, including improvement in crop pollination and in honey production, turning Brazil into a major exporter, the negative impacts-such as swarming, aggressive behavior, and the ability to mass attack-resulted in serious and fatal envenomation with humans and animals. Victims of bee attacks usually develop a severe envenomation syndrome characterized by the release of a large amount of cytokines [interleukins (IL) IL-1, IL-6, IL-8], and tumor necrosis factor (TNF). Subsequently, such cytokines produce an acute inflammatory response that triggers adverse effects on skeletal muscles; bone marrow; hepatic and renal functions; and cardiovascular, central nervous, and immune systems. Finally, the aim of the present review is to study historical characteristics and current status of Africanized bees' spread, the composition of their venom, the impact of the bees on the Brazilian economy and ecology, and clinical aspects of their stings including immune response, and to suggest a protocol for bee sting management since there is no safe and effective antivenom available.

Effects of Natural Infestations of the Mite Varroa destructor on the Development of Africanized Honeybee Workers (Apis mellifera)

The mite Varroa destructor (Anderson & Treuman 2000) has caused extensive damage to beekeeping worldwide. In Brazil, weather conditions and the strains of bees do not provide ideal conditions for mite parasitism, which is reflected in the low number of deaths of colonies caused by varroatosis well as the stability of infestation levels. The aim of this study was to evaluate the damage caused by the mite infestation in hives maintained in natural conditions. For this purpose the number of mites per bee was calculated and used to quantify the level of infestation in each colony. To record the mortality rates of parasitized bees during development daily checks were performed. The data were analyzed by G test of independence and a Test of Proportions. The results indicate that the rate of mortality of pupae and larvae was proportional to the degree of infestation in each colony, and all colonies showed mortality rates significantly higher than the control rate. A significant interaction among death rates recorded between the third and fourth days of larval life and the total death of larvae was found (G Test = 50.22; P < 0.0001). So, it can be concluded that bee inbreeding contributed significantly to the increase of the larval rate of mortality. In Africanized honeybee colonies infested by the mite Varroa destructor mortality rates in conditions of natural infestation varied from 6.65 to 9.89% in pupae (<(x)over bar>= 8.78%) and from 6.13 to 13.48% in larvae ((x) over bar = 9.91%), against 3.85% and 3.74% in the control colony, respectively. Therefore, in the infested colonies the average rates of mortality caused by the harmful effects of the mite were, respectively, 2.28 times and 2.65 times greater in those two developmental stages.

Effect of paprika on the ovarian development of Africanized honeybee workers (Apis mellifera L.) in queenless colonies

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Side-effects of thiamethoxam on the brain andmidgut of the africanized honeybee Apis mellifera (Hymenopptera: Apidae)

The development of agricultural activities coincides with the increased use of pesticides to control pests, which can also be harmful to nontarget insects such as bees. Thus, the goal of this work was assess the toxic effects of thiamethoxam on newly emerged worker bees of Apis mellifera (africanized honeybee-AHB). Initially, we determined that the lethal concentration 50 (LC50) of thiamethoxam was 4.28 ng a.i./μL of diet. To determine the lethal time 50 (LT50), a survival assay was conducted using diets containing sublethal doses of thiamethoxam equal to 1/10 and 1/100 of the LC50. The group of bees exposed to 1/10 of the LC50 had a 41.2% reduction of lifespan. When AHB samples were analyzed by morphological technique we found the presence of condensed cells in the mushroom bodies and optical lobes in exposed honeybees. Through Xylidine Ponceau technique, we found cells which stained more intensely in groups exposed to thiamethoxam. The digestive and regenerative cells of the midgut from exposed bees also showed morphological and histochemical alterations, like cytoplasm vacuolization, increased apocrine secretion and increased cell elimination. Thus, intoxication with a sublethal doses of thiamethoxam can cause impairment in the brain and midgut of AHB and contribute to the honeybee lifespan reduction. © 2013 Wiley Periodicals, Inc.

MALDI Imaging Analysis of Neuropeptides in the Africanized Honeybee (Apis mellifera) Brain: Effect of Ontogeny

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ovariole number - a predictor of differential reproductive success among worker subfamilies in queenless honeybee (Apis mellifera L.) colonies

A honeybee queen normally mates with 10-20 drones, and reproductive conflicts may arise among a colony's different worker patrilines, especially after a colony has lost its single queen and the workers commence egg laying. In this study, we employed microsatellite markers to study aspects of worker reproductive competition in two queenless Africanized honeybee colonies. First, we determined whether there was a bias among worker patrilines in their maternity of drones and, second, we asked whether this bias could be attributed to differences in the degree of ovary activation of workers. Third, we relate these behavioral and physiological factors to ontogenetic differences between workers with respect to ovariole number. Workers from each of three (colony A) and one (colony B) patrilineal genotypes represented less than 6% of the worker population, yet each produced at least 13% of the drones in a colony, and collectively they produced 73% of the drones. Workers representing these genotypes also had more developed follicles and a greater number of ovarioles per ovary. Across all workers, ovariole development and number were closely correlated. This suggests a strong effect of worker genotype on the development of the ovary already in the postembryonic stages and sets a precedent to adult fertility, so that

Analysis of Mortality in Africanized Honey Bee Colonies with High Levels of Infestation by Varroa destructor

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Invasive Africanized honeybees change the structure of native pollination networks in Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Heritability of sting characters in Africanized honeybees

In this paper we proposed to estimate the heritability of seven morphological characters that compose the sting apparatus ofthe Africanized honeybee workers. An experimental design to estimate genetic parameters was based on the method developed by Oldroyd and Moran. This method was modified to eliminate within-colony environmental effects associated with the additive genetic variance. The estimated h2 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).

Development of worker ovaries in Brazilian Africanized honeybees (Hymenoptera: Apidae)

The present paper compares the worker ovaries development in queen right and orphaned colonies of Brazilian Africanized honeybee. The results show that in both colonies some workers starting 20 days after emergence, present some kind of ovary development. As the workers from queen right colony get older the degree of the ovary development increases. Vitellogenesis in worker ovaries may occur in queen right and orphaned colonies, but its frequency is lower in queen right colonies.

Effects of sublethal dose of fipronil on neuron metabolic activity of africanized honeybees

Fipronil is a neurotoxic insecticide that inhibits the gamma-aminobutyric acid receptor and can affect gustative perception, olfactory learning, and motor activity of the honeybee Apis mellifera. This study determined the lethal dose (LD50) and the lethal concentration (LC50) for Africanized honeybee and evaluated the toxicity of a sublethal dose of fipronil on neuron metabolic activity by way of histochemical analysis using cytochrome oxidase detection in brains from worker bees of different ages. In addition, the present study investigated the recovery mechanism by discontinuing the oral exposure to fipronil. The results showed that mushroom bodies of aged Africanized honeybees are affected by fipronil, which causes changes in metabolism by increasing the respiratory activity of mitochondria. In antennal lobes, the sublethal dose of fipronil did not cause an increase in metabolic activity. The recovery experiments showed that discontinued exposure to a diet contaminated with fipronil did not lead to recovery of neural activity. Our results show that even at very low concentrations, fipronil is harmful to honeybees and can induce several types of injuries to honeybee physiology. © 2012 Springer Science+Business Media New York.

Africanized honeybees in urban areas: a public health concern

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)