Impact of chronic neonicotinoid exposure on honeybee colony performance and queen supersedure

BACKGROUND: Honeybees provide economically and ecologically vital pollination services to crops and wild plants. During the last decade elevated colony losses have been documented in Europe and North America. Despite growing consensus on the involvement of multiple causal factors, the underlying interactions impacting on honeybee health and colony failure are not fully resolved. Parasites and pathogens are among the main candidates, but sublethal exposure to widespread agricultural pesticides may also affect bees. METHODOLOGY/PRINCIPAL FINDINGS: To investigate effects of sublethal dietary neonicotinoid exposure on honeybee colony performance, a fully crossed experimental design was implemented using 24 colonies, including sister-queens from two different strains, and experimental in-hive pollen feeding with or without environmentally relevant concentrations of thiamethoxam and clothianidin. Honeybee colonies chronically exposed to both neonicotinoids over two brood cycles exhibited decreased performance in the short-term resulting in declining numbers of adult bees (-28%) and brood (-13%), as well as a reduction in honey production (-29%) and pollen collections (-19%), but colonies recovered in the medium-term and overwintered successfully. However, significantly decelerated growth of neonicotinoid-exposed colonies during the following spring was associated with queen failure, revealing previously undocumented long-term impacts of neonicotinoids: queen supersedure was observed for 60% of the neonicotinoid-exposed colonies within a one year period, but not for control colonies. Linked to this, neonicotinoid exposure was significantly associated with a reduced propensity to swarm during the next spring. Both short-term and long-term effects of neonicotinoids on colony performance were significantly influenced by the honeybees' genetic background. CONCLUSIONS/SIGNIFICANCE: Sublethal neonicotinoid exposure did not provoke increased winter losses. Yet, significant detrimental short and long-term impacts on colony performance and queen fate suggest that neonicotinoids may contribute to colony weakening in a complex manner. Further, we highlight the importance of the genetic basis of neonicotinoid susceptibility in honeybees which can vary substantially.

Africanized honey bee (Apis mellifera) venom profiling: Seasonal variation of melittin and phospholipase A(2) levels

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

Identification of a novel melittin isoform from Africanized Apis mellifera venom

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

Pustular dermatosis caused by fire ant (Solenopsis invicta) stings in a dog

This paper reports a case of spontaneous fire ant sting dermatitis in canine. The skin lesions consisted of nonfollicular, grouped pustules in the abdominal region. Several fire ants were found attached to the lesional skin. Histopathological findings included an intraepidermal neutrophilic pustule and predominantly neutrophilic interstitial dermatitis. An extensive area of collagen degeneration was also observed below the epidermal pustule. These clinical and histopathological findings are remarkable similar to those observed in fire ant stings in humans.

Injuries caused by scorpionfishes and (Scorpaena plumieri Bloch, 1789 Scorpaena brasiliensis Cuvier 1829) in the Southwestern Atlantic Ocean (Brazilian coast): epidemiologic, clinic and therapeutic aspects of 23 stings in humans

Fishes of the family Scorpaenidae are responsible for severe injuries and occasionally deaths in humans around the world. The more venomous fishes on the Brazilian coast and in the Southwestern Atlantic region are classified in the genus Scorpaena (family Scorpaenidae). However, there are few studies on the venomous apparatus, the effects of the venom, or clinical aspects of human envenoming provoked by Atlantic scorpionfishes.In this communication, the authors present 23 accidents caused by scorpionfishes of the genus Scorpaena among fishermen, and report the species that provoked the injuries, the circumstances of contacts, the clinical aspects observed and the therapeutic measures utilized for control of the symptoms of the victims. The intense pain and the systemic findings observed in the patients were very frequent and we think that the injuries provoked by scorpionfishes should be considered the most important manifestations caused by venomous fishes of the East Atlantic Ocean. (C) 2003 Elsevier B.V. Ltd. All rights reserved.

In situ localization of heat-shock proteins and cell death labelling in the salivary gland of acaricide-treated honeybee larvae

The effects of the acaricides, rotenone and oxalic acid (OA) on salivary glands of honeybee larvae were evaluated. Immunohistochemical methods were used to detect cell death and heat-shock protein (HSP70 and 90) localizations. Heat-shock proteins (HSP70 and 90) were localized in the cytoplasm and/or the nuclei of secretory gland cells, both under stress and in normal conditions. In rotenone-treated larvae, there were no changes in the normal level of cell death and also there were no morphological alterations in the secretory cells. In the larvae treated with oxalic acid, the salivary gland showed varying degrees of morphological cellular alteration and an increase in the cell death level. The present data suggest that stress-induced HSP70 might have an antiapoptotic effect while the stress-induced HSP90 might have a chaperone function in the larval salivary glands.

Morphomettic changes on honeybee Apis mellifera L. workers fat body cells after juvenile hormone topic application at emergence

The effect of topical application of juvenile hormone (JH) over the lifetime of worker bees was evaluated in Apis mellifera, by measuring the area of the two cell types, trophocytes and oenocytes, found in the fat body. Topical application of 1 mu l of a 1 mu g/mu l solution of JH in acetone to the abdomens of newly emerged workers produced an increase in cell size, in both types of cell of 5-day-old treated workers in relation to the untreated control. The treatment was more effective on the oenocytes, since there were significant differences compared to the averages of the treatments and the interaction of the treatments with the age of the workers. The developmental pattern seemed to differ from the treated group. However, subsequent effects were probably dependent on different, natural variations in hormonal levels. (c) 2007 Elsevier Ltd. All rights reserved.

Relationship among Apis mellifera L. stings, swarming and climate conditions in the city of Rio Claro, SP, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Morphological alterations induced by boric acid and fipronil in the midgut of worker honeybee (Apis mellifera L.) larvae

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Bee Visitors of Quaresmeira Flowers (Tibouchina granulosa Cogn.) in the Region of Dourados (MS-Brasil)

This research was developed in the center-urban area at the city of Dourados (MS), in Tibouchina granulosa trees, a plant popularly known as quaresmeira in Brazil. The floral visitors of this species were recorded in three daily periods: 7 - 8 a.m., 1 - 2 p.m. and 4 - 5 p. m. Bee visitors of those plants were collected with an entomological net when they landed on the flowers. The bees were anesthetized in a closed camera containing etila acetate, conserved in Dietrich ' s fixative and, soon afterwards, transferred to 70% ethyl alcohol for subsequent identification. Almost 300 specimens of Africanized Apis mellifera, Trigona spinipes and Tetragonisca angustula were collected. The presence of these three species of bees in the flowers of T. granulosa suggests that they can be considered the main floral visitors of that vegetal species. T. angustula workers did not visit the flowers of T. granulosa between 7 and 8 a.m., but they were the main floral visitors from 4 to 5 p.m. The workers of T. spinipes presented a very aggressive behavior against the Africanized A. mellifera workers on the quaresmeira flowers, defending the food sources with strength and efficiency and provoking a drastic reduction in the number of honeybee visits between 1 and 2 p.m. Nevertheless, they did not interfere in the opportunistic activity of foraging by T. angustula workers, mainly between 4 and 5 p.m. The most important result of this research was the detection of the Competitive Exclusion Principle between A. mellifera and T. spinipes species in relation to the foraging behavior, when they exploit the floral resources of T. granulosa.

Effect of topical application of juvenile hormone (JH) in honeybee worker larvae on the development of the Dufour's and Koschewnikow's glands

In order to investigate the action of the juvenile hormone (JH) on honeybee caste differentiation two exocrine glands, Koschewnikow and Dufour glands, were chosen for study. Two combs (I & II) were taken from a single posture of a queen to use for this research. In comb I the larvae were treated with a topical application of JH in Acetone, and those from the comb II (control group) received only Acetone. Immediately after the emergence of the workers, their glands were dissected and prepared for microscopic measurements. The results showed cell area reduction in the Koschewnikow gland induced by the JH application. The results for the Dufour gland displayed taller epithelial cells with the JH application. The difference in glandular responses to the JH relates to gland function, hormone targets, and individual homeostasis.

Three-Dimensional Modelling of Honeybee Venom Allergenic Proteases: Relation to Allergenicity

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

Thermoregulation in colonies of africanized and hybrids with Caucasian, Italian and Carniolan Apis mellifera honey bees

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

FLIGHT RANGE of AFRICANIZED HONEYBEES, Apis mellifera L. 1758 (Hymenoptera: Apidae) IN AN APPLE GROVE

O estudo do raio de ação das abelhas na coleta de néctar e pólen é de extrema importância para se saber até que distância a polinização por este inseto é promovida com eficiência. Para tanto, cinco colônias de abelhas africanizadas marcadas com 32P foram levadas a um pomar de maçã, sendo agrupadas no centro de uma área de 0,8 ha, a partir do qual foram colocadas estacas a cada 10m, formando quatro alas correspondentes às direções Norte, Sul, Leste e Oeste. As abelhas foram capturadas duas vezes por dia e por dez dias consecutivos, quando visitavam as flores das macieiras, até 50m do centro. Verificou-se que o número de abelhas marcadas coletadas, diminuiu linearmente à medida em que as mesmas se afastavam das colméias. Não houve interferência das orientações geográficas no comportamento de vôo das abelhas.