RESUMO
The stingless bee Tetragonisca angustula is an important pollinator of different agricultural and native crops. This study evaluated changes in the relative activity of esterases and critical electrolyte concentration in brain cells after exposure to pesticides malathion and thiamethoxam. Lethal concentration 50% showed greater toxicity of thiamethoxam in relation to malathion. Esterases EST-3 and EST-4 (carboxylesterase) were partially inhibited after contamination by contact and ingestion of malathion and contamination by contact with thiamethoxam, suggesting participation of these esterases in the metabolization of these compounds. The lowest critical electrolyte concentration (CEC) was found after contamination by malathion ingestion (0.15 M), indicating changes in gene expression. The alterations observed in the intensity of EST-3 and EST-4 and the chromatin structure indicate that pesticides can act in gene expression and be used as biomarkers of contaminant residues. Furthermore, knowing the susceptibility of T. angustulabees to pesticides, it would be possible to use this species for biomonitoring environmental quality in preserved areas and agroecosystems.(AU)
Assuntos
Animais , Praguicidas/toxicidade , Abelhas/fisiologia , Indicadores de Contaminação , Sintomas Toxicológicos/análiseRESUMO
Stingless bees are important pollinators for various plant crops. We investigated the susceptibility of Tetragonisca fiebrigito sublethal concentrations of insecticides fipronil, malathion, and thiamethoxam (administered through contact and ingestion) by determining the LC50values after 24hoursof exposure and analyzing changes in the activity of esterase isoenzymes and the chromatin in brain cells. The LC50values showed that all three insecticides were highly toxic through contact and ingestion. Electrophoretic analysis revealed that the relative EST-4 (carboxylesterase) activity in T. fiebrigi was partially inhibited by malathion and fipronil ingestion. Moreover, the EST-4 band intensity was increased following high-concentration thiamethoxam (contact) exposure, indicating the increased relative activity of this isoenzyme to detoxify the compound. In the cytochemical analysis of brain cells, the critical electrolyte concentration (CEC) points for the control stingless bees and malathion ingestion-exposed and thiamethoxam-exposed (contact and ingestion) stingless bees were in the range of 0.20-0.30 M MgCl2, whereas that for malathion contact-exposed bees was 0.15 M MgCl2, indicating chromatin relaxation and suggesting an increase in gene expression. In conclusion, T. fiebrigistingless bees are susceptible to the insecticides tested, and the parameters analyzed may be used as biomarkers to detect the presence of these compounds.(AU)
Assuntos
Animais , Abelhas , Expressão Gênica , Tiametoxam/toxicidade , Malation/toxicidade , Biomarcadores , Inseticidas/toxicidadeRESUMO
The potential of royal jelly production in Africanized honeybee colonies was evaluated using techniques involving two queens per colony in horizontal and vertical systems during the spring of 2019. The techniques were tested for their effect on cell acceptance (%); royal jelly production per colony (g), per harvest (g), and per position of cell bar (g) and compared with standard techniques (five and ten-frame hives) in southern Brazil. Results showed statistical significance in royal jelly production between methods. Vertical colonies produced a significantly greater amount of royal jelly per colony and per harvest (8.26 and 53.28±4.98 g) compared with single-queen colonies in ten-frame hives (4.30 and 32.76±3.57 g) and five-frame hives overlapping (2.03 and 14.45±2.48 g), but did not differ from two-queen horizontal colonies (8.09 and 46.81±4.90 g). In contrast, there was no significant difference in queen cell acceptance rate within vertical, horizontal, and ten-frame colonies. Royal jelly yield of two-queen vertical colonies increase as compared with standard colonies.(AU)
Assuntos
Animais , Pólen/efeitos adversos , Abelhas , BrasilRESUMO
Characteristics correlated with beekeeping production, less influenced by the environment and that can be controlled by management techniques, can help in the selection of colonies with higher production capacity, aiming to improve breeding programs. This research was carried out to evaluate the production of Africanized Apis mellifera drones and the longevity of spermatozoa from different genetic groups when supplemented with protein or not. Two genetic groups were used: one selected for royal jelly production from the Africanized honeybee breeding program and another without genetic selection. In both groups, the number of drone brood and the quality of semen were evaluated every 30 days, for five months. Statistical analysis was performed using Bayesian Inference. Statistical difference was found for the drone production among the treatments, and colonies without genetic selection produced more males (187.80 ± 11.15) than the selected colonies (93.07 ± 8.88). The selected colonies for royal jelly production presented greater efficiency in the reproductive cycle of males, because they produced fewer drones than colonies without genetic selection, however, with 31% greater semen viability.
Assuntos
Animais , Abelhas/embriologia , Abelhas/genética , Proteínas de Soja/análiseRESUMO
Characteristics correlated with beekeeping production, less influenced by the environment and that can be controlled by management techniques, can help in the selection of colonies with higher production capacity, aiming to improve breeding programs. This research was carried out to evaluate the production of Africanized Apis mellifera drones and the longevity of spermatozoa from different genetic groups when supplemented with protein or not. Two genetic groups were used: one selected for royal jelly production from the Africanized honeybee breeding program and another without genetic selection. In both groups, the number of drone brood and the quality of semen were evaluated every 30 days, for five months. Statistical analysis was performed using Bayesian Inference. Statistical difference was found for the drone production among the treatments, and colonies without genetic selection produced more males (187.80 ± 11.15) than the selected colonies (93.07 ± 8.88). The selected colonies for royal jelly production presented greater efficiency in the reproductive cycle of males, because they produced fewer drones than colonies without genetic selection, however, with 31% greater semen viability.(AU)
Assuntos
Animais , Abelhas/embriologia , Abelhas/genética , Proteínas de Soja/análiseRESUMO
This research was carried out to evaluate the royal jelly production in two trials. In Trial I, three genotypes of Africanized honeybees (Apis mellifera L.) were submitted to royal jelly production with two types of cups of different size and volume (conventional and Chinese model) and two types of supplements (commercial and formulated). A total of 24 colonies were used, two bars with different cups each, alternating between the upper or lower position of the frame. While in Trial II, 18 colonies, two genotypes, two types of cups and two types of supplement were tested. The evaluated parameters were: percentage of larvae accepted in upper and lower bars, royal jelly per cup (mg), and royal jelly per colony/collection (g). Chinese cups were not well accepted, fact that influenced in a negative way the production of general form, selected colonies were more sensible to the change of cups. Colonies of Africanized honeybees are not prepared to produce in cups of greater volume.
Assuntos
Animais , Abelhas/enzimologia , Abelhas/genéticaRESUMO
The objective of this research was to evaluate royal jelly production from Africanized honeybee queens of different lineages (lineage selected for honey production, lineage selected for royal jelly production and unselected) produced by single and double grafting and to compare royal jelly production among their offspring. Data were tested by double factorial analysis of variance and the means were compared by Tukey test at 5%. The parameters evaluated were: queen weight at emergence, percentage of larvae acceptance in the upper and lower bars, royal jelly per cup (mg) and royal jelly per colony/collection (g). Queens selected for honey presented greater weight at emergence, while the unselected queens were the lightest. Double grafting was better than simple grafting, since the queens were born 2.38% heavier. There was no difference (p > 0.05) in relation to royal jelly production according to neither the lineage nor even comparing the method by which the queens were produced. The cost of labor to produce queens by double grafting was much higher, as by the simple grafting about 170% more queens were born. The potential of Africanized honeybees with adequate production management and favorable environmental conditions favors the production of royal jelly.
Assuntos
Animais , Abelhas/fisiologia , Abelhas/genética , Abelhas/química , TransplanteRESUMO
This research was carried out to evaluate the royal jelly production in two trials. In Trial I, three genotypes of Africanized honeybees (Apis mellifera L.) were submitted to royal jelly production with two types of cups of different size and volume (conventional and Chinese model) and two types of supplements (commercial and formulated). A total of 24 colonies were used, two bars with different cups each, alternating between the upper or lower position of the frame. While in Trial II, 18 colonies, two genotypes, two types of cups and two types of supplement were tested. The evaluated parameters were: percentage of larvae accepted in upper and lower bars, royal jelly per cup (mg), and royal jelly per colony/collection (g). Chinese cups were not well accepted, fact that influenced in a negative way the production of general form, selected colonies were more sensible to the change of cups. Colonies of Africanized honeybees are not prepared to produce in cups of greater volume.(AU)
Assuntos
Animais , Abelhas/enzimologia , Abelhas/genéticaRESUMO
The objective of this research was to evaluate royal jelly production from Africanized honeybee queens of different lineages (lineage selected for honey production, lineage selected for royal jelly production and unselected) produced by single and double grafting and to compare royal jelly production among their offspring. Data were tested by double factorial analysis of variance and the means were compared by Tukey test at 5%. The parameters evaluated were: queen weight at emergence, percentage of larvae acceptance in the upper and lower bars, royal jelly per cup (mg) and royal jelly per colony/collection (g). Queens selected for honey presented greater weight at emergence, while the unselected queens were the lightest. Double grafting was better than simple grafting, since the queens were born 2.38% heavier. There was no difference (p > 0.05) in relation to royal jelly production according to neither the lineage nor even comparing the method by which the queens were produced. The cost of labor to produce queens by double grafting was much higher, as by the simple grafting about 170% more queens were born. The potential of Africanized honeybees with adequate production management and favorable environmental conditions favors the production of royal jelly.(AU)
Assuntos
Animais , Abelhas/química , Abelhas/fisiologia , Transplante , Abelhas/genéticaRESUMO
The neonicotinoid thiamethoxam is widely used in different agricultural crops, and it has a spectrum of action against insects, affecting both pests and pollinators, such as bees. In this study, the effects of exposure to sublethal concentrations of thiamethoxam on stingless bees Scaptotrigona bipunctata were evaluated. Foragers bees were exposed to the insecticide and subjected to genetic biochemical, histochemical, and morphological analyses after 24, 48, and 72 h of ingestion. Analysis of isoenzyme esterases revealed significant alterations in the relative activity of EST-4, a type II cholinesterase. Evaluation of the S. bipunctata brain revealed changes in the state of chromatin condensation according to the exposure time and concentration of neonicotinoid compared with the control. Morphological changes were observed in the midgut of this species at all concentrations and exposure times, which may interfere with various physiological processes of these insects. We can conclude that, although thiamethoxam at the concentrations evaluated did not cause high mortality, it induced concentration-dependent changes in bees by activating enzymes related with the protection for xenobiotic, internal morphology and probably these changes may lead to alterations in the activity of bees.