Reproductive Success of an Endangered Plant after Invasive Bees Supplant Native Pollinator Services

Arctomecon humilis (dwarf bear poppy) is an endangered gypsophile restricted to the St. George area in southern Utah, USA. Extirpation of the rare oligolectic bee Perdita meconis and decline of other native pollinators within the last 20 years has been largely attributed to the advent of invasive Africanized honeybees (AHBs), which have become the predominant pollinator for A. humilis. A three-year study was carried out to determine if reliance on AHBs had a negative effect on reproductive output. In the first year, pollen addition experiments were carried out in a small, isolated population to determine if pollinator scarcity or genetic factors affected reproductive output. In the subsequent two years, reproductive output studies were conducted across four populations. In all years, fruit set across study sites was exceptionally high. There was no consistent effect from flower number or interplant distance, which have historically been shown to have a significant impact on reproductive output prior to AHB arrival. The consequences and sustainability of this relatively young relationship between A. humilis and the AHB remain unclear. However, high reproductive success shows that the AHB is currently capable of adequately fulfilling pollinator services for A. humilis.

Foraging, spatial distribution and the effect of honeybees on soybean yield

The soybean is the most cultivated grain crop in Brazil and there are many efforts to protect visitor pollinators, especially honeybees. The understanding of honeybee behavior on soybean fields is important to growers to apply integrated pest management strategies to avoid harm the pollinators. The European bee (Apis mellifera Linnaeus, 1758 (Hymenoptera: Apidae)) is a social bee, with European origin, whose the worker length is 12 mm to 13 mm with darker chest hairs. In this sense, foraging hours of Apis on soybean, its spatial distribution, the effect of pollination on soybean yield and the effect of insecticides on honeybee behavior were investigated. Two experiments were carried out. The first experiment was performed in a soybean field with 79 sampling points and four insecticide treatments to understand the spatial distribution of honeybees. In addition, foraging behavior of honeybees was evaluated hourly from 7:00am to 7:00pm randomly on 40 sampling points. The second experiment was carried out in cages with and without honeybees to quantify the effect of pollination on soybean yield under spray of chemical insecticides. Four hives with Africanized honeybees (A. mellifera) were set around the area. The hives had approximately six to eight brood frames and two to four food frames. Insecticides were sprayed as diferent treatments. The first experiment showed that honeybees prefer to forage on soybean flowers from 10:00am to 1:00pm and have random distribution. The use of A. mellifera as a pollinator did not increase the yield of soybean. Besides the particular manner of experiment’s conduction, the information of foraging behavior of honeybees, the pollination effect on soybeans yield and the effect of insecticides on honeybees are prudently discussed and some implication for soybean producers are also carefully addressed to avoid insecticide applications to harm pollinators. It is important to understand that the effect of pollination on yield of soybean depends on environmental conditions, cultivars, the effect of caging plants, and the abnormally high concentration of bees in the cages

Survey on the types of nesting of Africanized honeybees in urban areas of semiarid regions and rationalization of swarm capture for the benefit of the community

Africanized honeybees (Apis mellifera L.) are abundant and widely adaptable insects that spread rapidly in tropical environments. However, their strong defensive instinct can lead to attacks on humans and animals, causing disturbances in cities. This study aimed to evaluate the nesting characteristics of Africanized honeybees in Mossoró, RN, to generate relevant information for the control of the population of these insects and prevent accidents in urban areas in the Brazilian Semiarid. This survey was conducted from April 2015 to March 2018. The following information on swarms was collected from 487 recorded occurrences: date of survey, structure of the bee site, occurrence of nesting, population size, defensiveness of the bees, and presence of queen and drones. Although the swarms reproduced throughout the year, the breeding of queens and drones increased in the rainy season (January-June). Peak swarming occurred in April-September, when there is greater availability of flowers in the region and the average ambient temperature is mild. The swarms adopted a generalist approach when choosing their nesting site, occupying structures such as tires, tree trunks, buckets, sewage, and cardboard boxes. Most swarms were found in open sites (exposed swarms). The Africanized honeybees were more selective when looking for a nest construction site than when looking for a temporary site for landing and resting. The swarms were generally small (up to 20,000 bees) and not very defensive, which facilitated their rescue in populous urban areas.

Electrophysiologic and behavioral responses mediated by volatiles involved in the repellency of Apis mellifera (Lepeletier) (Hymenoptera: Apidae)

Repellent volatiles to insects might be an important tool for management of bees in areas which the presence of these organisms is not required. This study aimed to evaluate the electroantennal and behavioral responses of Africanized honeybees (workers), Apis mellifera (Lepeletier) (Hymenoptera Apidae), at different ages, to benzaldehyde (BA) and methyl anthranilate (MA) and to evaluate the potential repellency of these compounds under field conditions. Laboratory tests were conducted to study electroantennographic responses (mV) and chemotactic behavior of worker bees aged 1-5 (young) and 20-30 (old) days in four choice olfactometer. Electrophysiological responses to each compound did not differ between young and old workers. Bees antennae (young) triggered significantly greater responses to BA, in the older ones, a higher response was observed to MA, both compared to control (ethanol). The threshold response to BA and MA was achieved at 10 µg/µL, both compounds repelled bees at the same dose in olfactometer. Treatments with BA and MA, in field conditions, were less visited by scouter honey bees than those without these compounds (control).

Electrophysiologic and behavioral responses mediated by volatiles involved in the repellency of Apis mellifera (Lepeletier) (Hymenoptera: Apidae)

Repellent volatiles to insects might be an important tool for management of bees in areas which the presence of these organisms is not required. This study aimed to evaluate the electroantennal and behavioral responses of Africanized honeybees (workers), Apis mellifera (Lepeletier) (Hymenoptera Apidae), at different ages, to benzaldehyde (BA) and methyl anthranilate (MA) and to evaluate the potential repellency of these compounds under field conditions. Laboratory tests were conducted to study electroantennographic responses (mV) and chemotactic behavior of worker bees aged 1-5 (young) and 20-30 (old) days in four choice olfactometer. Electrophysiological responses to each compound did not differ between young and old workers. Bees antennae (young) triggered significantly greater responses to BA, in the older ones, a higher response was observed to MA, both compared to control (ethanol). The threshold response to BA and MA was achieved at 10 µg/µL, both compounds repelled bees at the same dose in olfactometer. Treatments with BA and MA, in field conditions, were less visited by scouter honey bees than those without these compounds (control).

Bee species (Hymenoptera: Anthophila) in a Cerrado-Atlantic Forest ecotone: nesting habits related to foraging activity in a degraded forest fragment

The aim of this paper was to determine the species diversity and frequency of foraging performed by bees in fragment of degraded forest in a Cerrado-Atlantic Forest ecotone area, also considering the nesting habit of each species. The foraging frequency of each bee species in the main floral sources was recorded for 12 consecutive months. The nesting site was used to sort the bees into guilds: above-ground nesting bees, ground-nesting bees, and both below and above-ground nesting bees. The guild of ground-nesting bees had 24 species and accounted for 17.48 % of the foraging rate, while above-ground nesting bees were represented by 12 species which made 8.89 % of the foraging rate, and both below and above-ground nesting bees comprised five species which made 0.43 % of the foraging rate. Africanized honeybee performed 73.20 % of the foraging flight, and presented a broad food niche. Therefore, in the forest fragment studied, two types of impacts which make difficult the survival and maintenance of the native bee fauna were observed: the dominance over floral resources by the exotic species the Africanized honeybees; the small number of large trees.

Epidemiology of envenomation by Africanized honeybees in the state of Rio Grande do Norte, Northeastern Brazil

ABSTRACT: Introduction: In the American continent, accidents caused by honeybees are a public health problem due to the high incidence and severity of the cases. Despite its medical importance, there are few epidemiological studies on this topic in Brazil, especially referring to the Northeastern states. The present study aims to describe the epidemiological features of honeybee envenomation cases in the state of the Rio Grande do Norte, Northeastern Brazil, from 2007 to 2014. Methods: Data were collected from the Notifiable Diseases Information System database of the Health Department of Rio Grande do Norte. Results: We analyzed a total of 2,168 cases. Cases occurred in all months of the years studied, reaching higher frequencies from June to October. Most incidents happened in urban areas and involved men, with victims aged between 20 and 39 years. Victims were mainly stung on the head and hand, and they received medical care predominantly within 3 hours after the injury. Local manifestations were more frequent than systemic ones. Clinically, most cases were mild and progressed to cure. Conclusion: The high number of honeybee sting cases shows that Rio Grande do Norte may be an important risk area for such injury.

Foraging activity of africanized honeybees (Apis mellifera L.): A study of nectar and pollen resources on a temporal scale

The spatial and temporal distribution of food resources, as well as the type, quantity, and quality of the foods stocked in the hive are the principal regulatory factors of the choice and intensity of floral resource harvesting by bees. We evaluated the annual foraging activity of Africanized honeybees Apis mellifera L. (Apidae) on the most abundant natural food resources available. Nineteen abundant plant species susceptible to foraging by bee communities in the interior of a secondary growth forest fragment with a transition physiognomy between Atlantic Forest and Cerradão vegetation were accompanied to estimate the intensity of floral resource collection by Africanized honeybees A. mellifera during the year. We determined the productivity of the flowers (the quality and quantity of nectar and/or pollen made available) and floral abundance (the quantities of flowers produced and the duration of flowering) of the 19 plant species selected. Africanized honeybees A. mellifera collected floral resources from 11 species. The intensities of visits per flower and per area of floral exposition were greater among plant species visited by Africanized honeybees when bee collecting behavior resulted in pollen transfer to the floral stigmas. It is estimated that 70.5% of all visits by Africanized honeybees A. mellifera individuals during the year in the study area occurred on Senegalia polyphylla (DC.) Britton & Rose (Fabaceae), Grazielia cf. dimorpholepis (Baker) R.M.King & H.Rob (Asteraceae), and Gouania cf. latifolia Reissek (Rhaminaceae); those visits demonstrated seasonal patterns, with peaks of activity between January and April. Weak foraging activity was observed in June and between June and November.Atividade de forrageio de abelhas africanizadas (Apis mellifera L.): um estudo das fontes de néctar e pólen em uma escala temporalResumo. A distribuição espacial e temporal dos recursos alimentares, bem como o tipo, quantidade e qualidade do alimento estocado na colmeia são os principais fatores reguladores na escolha e intensidade da coleta dos recursos florais pelas abelhas. O objetivo desse trabalho foi avaliar a atividade anual de forrageio de abelhas africanizadas Apis mellifera L. (Apidae) nas fontes alimentares naturais mais abundantes. A coleta de dados foi realizada em 19 espécies vegetais abundantes e suscetíveis ao forrageio pela comunidade de abelhas no interior de um fragmento de floresta secundária com fisionomia em transição entre Mata Atlântica e Cerradão, durante um ano. Para estimar a intensidade de coleta de recursos florais pelas abelhas africanizadas A. mellifera, foi determinada a produtividade das flores (qualidade e quantidade do néctar e/ou pólen alocada nas flores) e a abundância (quantidade de flores e duração do florescimento) das 19 espécies vegetais selecionadas. As abelhas africanizadas A. mellifera coletaram recursos florais em 11 espécies vegetais. As intensidades de visitas por flor e áreas de exposição floral foram superior nas espécies de plantas que foram visitadas pelas abelhas africanizadas A. mellifera cujos comportamentos de coleta resultavam em transferência de pólen aos estigmas das flores. Estima-se que 70,5% de todas as visitas promovidas por A. mellifera africanizada no decorrer do ano na região de estudo ocorreram em Senegalia polyphylla (DC.) Britton & Rose (Fabaceae), Grazielia cf. dimorpholepis (Baker) R.M.King & H.Rob (Asteraceae), e Gouania cf. latifolia Reissek (Rhaminaceae), demonstrando, dessa forma, um padrão sazonal, com picos de atividade em janeiro, abril e agosto, respectivamente. Por outro lado, houve fraca atividade de forrageio em junho e entre setembro e novembro.