Techniques for the In Vitro Production of Queens in Stingless Bees (Apidae, Meliponini)

Considering the ecological importance of stingless bees as caretakers and pollinators of a variety of native plants makes it necessary to improve techniques which increase of colonies’ number in order to preserve these species and the biodiversity associated with them. Thus, our aim was to develop a methodology of in vitro production of stingless bee queens by offering a large quantity of food to the larvae. Our methodology consisted of determining the amount of larval food needed for the development of the queens, collecting and storing the larval food, and feeding the food to the larvae in acrylic plates. We found that the total average amount of larval food in a worker bee cell of F. varia is approximately 26.70 } 3.55 μL. We observed that after the consumption of extra amounts of food (25, 30, 35 and 40 μL) the larvae differentiate into queens (n = 98). Therefore, the average total volume of food needed for the differentiation of a young larva of F. varia queen is approximately 61.70 } 5.00 μL. In other words; the larvae destined to become queens eat 2.31 times more food than the ones destined to become workers. We used the species Frieseomelitta varia as a model, however the methodology can be reproduced for all species of stingless bees whose mechanism of caste differentiation depends on the amount of food ingested by the larvae. Our results demonstrate the effectiveness of the in vitro technique developed herein, pointing to the possibility of its use as a tool to assist the production of queens on a large scale. This would allow for the artificial splitting of colonies and contribute to conservation efforts in native bees

Flavonoides, Actividades Antibacteriana y Antioxidante de Propóleos de Abejas Sin Aguijón, Melipona quadrifasciata , Melipona compressipes , Tetragonisca angustula y Nannotrigona sp. de Brasil y Venezuela

Flavonoids content, antibacterial and antioxidant activities of Brazilian and Venezuelan propolis from stingless bees, Melipona quadrifasciata , Melipona compressipes , Tetragonisca angustula , and Nannotrigona sp. were evaluated using ethanolic extracts of propolis (EEP) against Gram positives bacteria, Staphylococcus aureus and Micrococcus luteus . The propolis samples were collected in three locations, São Paulo state, Brazil, and Miranda and Guárico states, Venezuela, from November 2003 to April 2004. The results showed that the flavonoid content was very low for all samples, between 0.19 and 0.32%. The antioxidant activity was lower than 22 sec for all samples (3-5 sec of average). The EEP from Melipona quadrifasciata bees showed higher antioxidant activity than the other stingless bees. All EEP showed high antibacterial activity, with an inhibition halo between 11 to 30 mm, against Staphylococcus aureus and Micrococcus luteus, for all Brazilian and Venezuelan samples. EEP from Nannotrigona sp. showed higher antibacterial activity than other bees. The propolis studied showed high antibacterial and antioxidant activity, despite lower flavonoids percentagesEn el presente trabajo se evaluaron el contenido de flavonoides, las actividades antimicrobianas y antioxidante de los propóleos de abejas sin aguijón, Melipona quadrifasciata , Melipona compressipes , Tetragonisca angustula y Nannotrigona sp., mediante el uso del extracto etanólico de propóleos (EEP) contra las bacterias Gram positivas, Staphylococcus aureus y Micrococcus luteus . El propóleos fue colectado en los estados Miranda y Guárico, Venezuela, y São Paulo, Brasil, durante el período de noviembre de 2003 a abril de 2004. Los contenidos de flavonoides fueron muy bajos, variando de 0,19 a 0,32%. La actividad antioxidante en todas las muestras fue menor a 22 seg, con media de 3 a 5 seg. Los EEP de M. quadrifasciata mostró la mayor actividad antioxidante. Los EEP de todas las muestras tuvieron una elevada actividad antimicrobiana contra Staphylococcus aureus y Micrococcus luteus, con halos de inhibición de 11 a 30 mm, tanto en las muestras de Brasil como en las de Venezuela. El EEP de la Nannotrigona sp. mostraron mayor actividad antimicrobiana que los de otras abejas. Se concluye que los propóleos de las abejas sin aguijón estudiadas poseen elevadas actividades antioxidante y antimicrobianas, aunque los contenidos de flavonoides sean bajos

Techniques for the In Vitro Production of Queens in Stingless Bees (Apidae, Meliponini)

Considering the ecological importance of stingless bees as caretakers and pollinators of a variety of native plants makes it necessary to improve techniques which increase of colonies’ number in order to preserve these species and the biodiversity associated with them. Thus, our aim was to develop a methodology of in vitro production of stingless bee queens by offering a large quantity of food to the larvae. Our methodology consisted of determining the amount of larval food needed for the development of the queens, collecting and storing the larval food, and feeding the food to the larvae in acrylic plates. We found that the total average amount of larval food in a worker bee cell of F. varia is approximately 26.70 } 3.55 μL. We observed that after the consumption of extra amounts of food (25, 30, 35 and 40 μL) the larvae differentiate into queens (n = 98). Therefore, the average total volume of food needed for the differentiation of a young larva of F. varia queen is approximately 61.70 } 5.00 μL. In other words; the larvae destined to become queens eat 2.31 times more food than the ones destined to become workers. We used the species Frieseomelitta varia as a model, however the methodology can be reproduced for all species of stingless bees whose mechanism of caste differentiation depends on the amount of food ingested by the larvae. Our results demonstrate the effectiveness of the in vitro technique developed herein, pointing to the possibility of its use as a tool to assist the production of queens on a large scale. This would allow for the artificial splitting of colonies and contribute to conservation efforts in native bees

Physiological and genetic mechanisms underlying caste development, reproduction and division of labor in stingless bees

Investigations on physiological and molecular mechanisms underlying developmental and reproductive differentiation in social bees center on the question of how different patterns of larval nutrition can affect hormonal dynamics and how these drive differential gene expression. Differential expression analyses and the generation of AFLP markers now enable us to re-examine the question of genetic caste determination in the genus Melipona. The comparison of vitellogenin expression in three species of stingless bees suggests divergence in regulatory mechanisms that directly relate to the mode of worker reproduction. As in honey bees, this indicates alternative functions for vitellogenin in the life cycle of adult workers. The diversity in life histories and their associated specific physiologies make the stingless bees a rich resource for information on evolutionary trajectories that have generated phenotypic plasticity in social Hymenoptera

Agrochemical synergism imposes higher risk to Neotropical bees than to honeybees

Bees are key pollinators whose population numbers are declining, in part, owing to the effects of different stressors such as insecticides and fungicides. We have analysed the susceptibility of the Africanized honeybee, Apis mellifera, and the stingless bee, Partamona helleri, to commercial formulations of the insecticides deltamethrin and imidacloprid. The toxicity of fungicides based on thiophanate-methyl and chlorothalonil were investigated individually and in combination, and with the insecticides. Results showed that stingless bees were more susceptible to insecticides than honeybees. The commercial fungicides thiophanate-methyl or chlorothalonil caused low mortality, regardless of concentration; however, their combination was as toxic as imidacloprid to both species, and over 400-fold more toxic than deltamethrin for A. mellifera. There were highly synergistic effects on mortality caused by interactions in the mixture of imidacloprid and the fungicides thiophanate-methyl, chlorothalonil and the combined fungicide formulation in A. mellifera, and also to a lesser extent in P. helleri. By contrast, mixtures of the deltamethrin and the combined fungicide formulation induced high synergy in P. helleri, but had little effect on the mortality of A. mellifera. Differences in physiology and modes of action of agrochemicals are discussed as key factors underlying the differences in susceptibility to agrochemicals

Efficacy and Residual Toxicity of Insecticides on Plutella xylostella and Their Selectivity to the Predator Solenopsis saevissima

We evaluated the efficacy and residual toxicity of nine commercial insecticides on Plutella xylostella and their selectivity to the predator ant Solenopsis saevissima under laboratory and field conditions. First, to test the insecticides’ effectiveness and selectivity, we conducted concentration-response bioassays on both species and the mortalities were recorded 48 h after exposure. Next, rapeseed plants were sprayed following label rate recommendations in the field. Finally, insecticide-treated leaves were removed from the field up to 20 days after application and both organisms were exposed to them as in the first experiment. Our concentration-response bioassay indicated that seven insecticides caused mortality ≥80% of P. xylostella: bifenthrin, chlorfenapyr, chlorantraniliprole, cyantraniliprole, indoxacarb, spinetoram, and spinosad. However, only chlorantraniliprole and cyantraniliprole caused mortality ≤30% of S. saevissima. The residual bioassay indicated that four insecticides had a long-lasting effect, causing mortality of 100% to P. xylostella 20 days after application: chlorantraniliprole, cyantraniliprole, spinetoram, and spinosad. For S. saevissima, bifenthrin caused mortality of 100% during the evaluated period. Additionally, mortality rates below 30% occurred four days after the application of spinetoram and spinosad. Thus, chlorantraniliprole and cyantraniliprole are safe options for P. xylostella management since their efficacy favor S. saevissima

Efficacy and Residual Toxicity of Insecticides on <i>Plutella xylostella</i> and Their Selectivity to the Predator <i>Solenopsis saevissima</i>

We evaluated the efficacy and residual toxicity of nine commercial insecticides on Plutella xylostella and their selectivity to the predator ant Solenopsis saevissima under laboratory and field conditions. First, to test the insecticides’ effectiveness and selectivity, we conducted concentration-response bioassays on both species and the mortalities were recorded 48 h after exposure. Next, rapeseed plants were sprayed following label rate recommendations in the field. Finally, insecticide-treated leaves were removed from the field up to 20 days after application and both organisms were exposed to them as in the first experiment. Our concentration-response bioassay indicated that seven insecticides caused mortality ≥80% of P. xylostella: bifenthrin, chlorfenapyr, chlorantraniliprole, cyantraniliprole, indoxacarb, spinetoram, and spinosad. However, only chlorantraniliprole and cyantraniliprole caused mortality ≤30% of S. saevissima. The residual bioassay indicated that four insecticides had a long-lasting effect, causing mortality of 100% to P. xylostella 20 days after application: chlorantraniliprole, cyantraniliprole, spinetoram, and spinosad. For S. saevissima, bifenthrin caused mortality of 100% during the evaluated period. Additionally, mortality rates below 30% occurred four days after the application of spinetoram and spinosad. Thus, chlorantraniliprole and cyantraniliprole are safe options for P. xylostella management since their efficacy favor S. saevissima

Bayesian Multi-Targets Strategy to Track <em>Apis mellifera</em> Movements at Colony Level

Interactive movements of bees facilitate the division and organization of collective tasks, notably when they need to face internal or external environmental challenges. Here, we present a Bayesian and computational approach to track the movement of several honey bee, Apis mellifera, workers at colony level. We applied algorithms that combined tracking and Kernel Density Estimation (KDE), allowing measurements of entropy and Probability Distribution Function (PDF) of the motion of tracked organisms. We placed approximately 200 recently emerged and labeled bees inside an experimental colony, which consists of a mated queen, approximately 1000 bees, and a naturally occurring beehive background. Before release, labeled bees were fed for one hour with uncontaminated diets or diets containing a commercial mixture of synthetic fungicides (thiophanate-methyl and chlorothalonil). The colonies were filmed (12 min) at the 1st hour, 5th and 10th days after the bees’ release. Our results revealed that the algorithm tracked the labeled bees with great accuracy. Pesticide-contaminated colonies showed anticipated collective activities in peripheral hive areas, far from the brood area, and exhibited reduced swarm entropy and energy values when compared to uncontaminated colonies. Collectively, our approach opens novel possibilities to quantify and predict potential alterations mediated by pollutants (e.g., pesticides) at the bee colony-level

Suplementary material from Agrochemical synergism imposes higher risk to neotropical bees than to honeybees

Suplementary material containing the raw data of the concentration-mortality bioassays. The pesticide effects on pollinator biodiversity is a global trend that is garnering much concern. Initially, there was significant concern about pesticide-mediated reductions in the number of honey bee pollinators, primarily Apis mellifera in the USA and in some European countries, but those initial concerns have been replaced by a broader concern related to the decline of pollinator bees in general. Here, we evaluated the impact of multiple stressors (e.g., insecticides and fungicides) on Africanized honey bees and stingless bees that are the most important pollinator insects in agriculture landscapes at the Neotropical regions. We demonstrated that the synergistic effects of agrochemicals (e.g., insecticides and fungicides) pose an increased risk to the Neotropical stingless bees Partamona helleri compared to the Africanized A. mellifera, which reinforce the notion that A. mellifera is not a faithful model to assess the safety of agrochemicals when compared with other species of bees and emphasize the limited value of extrapolating results of toxicity bioassays from honey bees to native pollinator species