Attraction,deterrence or intoxication of bees (Apis mellifera) by plant allelochemicals

The influence of 63 dietary allelochemicals (alkaloids, terpenes, glycosides,etc.) on the feeding behaviour of bees (Apis mellifera) was tested in terms of deterrency and attraction. For 39 compounds a deterrent (mostly alkaloids, coumarins and saponins) and for 3 compounds an attractive response (mostly terpenes) was obtained in choice tests, which allowed the calculation of respective ED₅₀-values. Under no-choice conditions, 17 out of 29 allelochemicals caused mortality at concentrations between 0.003 and 0.6%. Especially toxic were alkaloids, saponins, cardiac glycosides and cyanogenic glycosides. These data show that bees which are confronted with plant allelochemicals in nectar and pollen, are not especially adapted (i.e. insensitive) to the plants' defence chemistry. GLC and GLS-MS data are given on the alkaloid composition of nectar and pollen ofBrugmansia aurea, Atropa belladonna andLupinus polyphyllus.     

Factors affecting the sex ratio in the honeybee mite <Emphasis Type="Italic">Varroa jacobsoni</Emphasis>

Study of the seasonal variation of the sex ratio in the honeybee mite Varroa jacobsoni demonstrated that sex determination was affected by temperature, order of reproductive cycles, and population densities in the host’s brood cell and the honeybee nest. The mechanism of reproduction ensuring adaptation of the mite to parasitism and reproduction on honeybees are discussed.     

The reproductive dilemmas of queenless red dwarf honeybee (Apis florea) workers

Honeybee (Apis) workers cannot mate, but retain functional ovaries. When colonies have lost their queen, many young workers begin to activate their ovaries and lay eggs. Some of these eggs are reared, but most are not and are presumably eaten by other workers (worker policing). Here we explore some of the factors affecting the reproductive success of queenless workers of the red dwarf honeybee Apis florea. Over a 2-year period we collected 40 wild colonies and removed their queens. Only two colonies remained at their translocated site long enough to rear males to pupation while all the others absconded. Absconding usually occurred after worker policing had ceased, as evidenced by the appearance of larvae. Dissections of workers from eight colonies showed that in A. florea, 6% of workers have activated ovaries after 4 days of queenlessness, and that 33% of workers have activated ovaries after 3 weeks. Worker-laid eggs may appear in nests within 4 days and larvae soon after, but this is highly variable. As with Apis mellifera, we found evidence of unequal reproductive success among queenless workers of A. florea. In the two colonies that reared males to pupation and which we studied with microsatellites, some subfamilies had much higher proportions of workers with activated ovaries than others. The significance of absconding and internest reproductive parasitism to the alternative reproductive strategies of queenless A. florea workers is discussed.     

新烟碱类杀虫剂对蜜蜂的急性毒性及风险评价

为新烟碱类杀虫剂合理使用提供科学依据,本研究采用饲喂法和点滴法测定了9种新烟碱类杀虫剂对蜜蜂的急性毒性效应,且根据风险商值法进行了风险评价,氟啶虫酰胺和吡蚜酮作为对照药剂。试验结果表明:6种新烟碱类杀虫剂(噻虫胺、呋虫胺、吡虫啉、烯啶虫胺、氟啶虫胺腈和噻虫嗪)对蜜蜂经口和接触毒性的48 h-LD50值为1.73×10-3(1.37×10-3~2.45×10-3)~35.3×10-2(30.5×10-2~41.4×10-2)μg·蜂-1,均属于高毒级;其次为氯噻啉,该药剂对蜜蜂经口和接触毒性的48 h-LD50值为56.4×10-2(40.9×10-2~95.5×10-2)和2.05(1.13~3.18)μg·蜂-1,分别为高毒和中毒;而啶虫脒和噻虫啉对蜜蜂经口和接触毒性的48 hLD50值为2.57(1.94~3.75)~9.85(8.23~11.6)μg·蜂-1,为中毒级。对照药剂氟啶虫酰胺和吡蚜酮对蜜蜂经口和接触毒性的48h-LD50值均100μg·蜂-1,为低毒级。风险评价结果表明:噻虫胺、呋虫胺、吡虫啉、噻虫嗪、氯噻啉、烯啶虫胺和氟啶虫胺腈对蜜蜂具有不可接受的风险,啶虫脒、噻虫啉和对照药剂氟啶虫酰胺、吡蚜酮对蜜蜂的风险可接受。因此,在害虫综合治理中,应谨慎使用新烟碱类杀虫剂,以免对蜜蜂产生严重的毒副作用。     

Ultrastructural and chemical characterization of egg surface of honeybee worker and queen-laid eggs

Summary. Worker policing in honeybees predicts the evolution of a mechanism to discriminate between queenand worker-born eggs. Although it has been postulated that this discrimination is based on an egg recognition pheromone, neither the chemistry nor the glandular source were elucidated. To verify whether egg discrimination might be based on structural differences, we compared the ultrastructure surface of queen-laid diploid and haploid eggs to that of worker-laid eggs using SEM. Only small differences between the different types of eggs were found. Thus, at least based on the fine structure of the egg surface, queen eggs are indistinguishable from worker-laid eggs.To explore the chemosensory hypothesis for egg discrimination, we conducted a detailed comparative chemical analysis of the different egg types. The coating of all egg types was dominated by linear alkanes, but queen eggs, diploid and haploid, differed from those of workers on two accounts: 1. The diversity of compounds found on queenlaid eggs was much greater than found on worker-laid eggs, mainly due to the number of hydrocarbons. 2. Acetates of some fatty alcohols, alkenes and especially monomethylalkanes were characteristic to queen eggs. The origin of the two latter substances and the acetates is still unknown. Whether these compounds constitute the signal that enables police workers to discriminate between queen- and workerborn eggs remains to be investigated.     

The transfer of active ingredients of insecticides and fungicides from an orchard to beehives

This investigation was undertaken to determine whether active ingredients (AIs) of currently recommended plant protection products (PPPs) could be transferred to beehives from apple and pear trees. A field trial was carried out with apple trees of Ligol and Idared variety, and pear trees of Conference variety. For pest and diseases control of fungal origin, recommended PPPs were applied. Samples of flowers from the above-mentioned varieties of fruit trees, of bees, brood and honey from beehives located in their direct neighborhood were collected regularly and analyzed for the presence of lambda-cyhalothrin (an insecticide) and cyprodinil, captan, fluopyram, kresoxim-methyl, penthiopyrad and trifloxystrobin (fungicides). In samples of flowers of Ligol variety, fluopyram residues (on average 0.621 µg single flower^?1) were at the highest levels, whereas in samples of pear flowers of Conference variety, and in flowers of Idared variety, captan residues (on average, respectively, 0.705 and 165.7 µg single flower^?1). In samples of bees and honey, residues of five AIs were detected, and in brood six AIs, whereby in each case captan residues prevailed, respectively, up to 585.2, 51.52 and 126.5 µg kg^?1 bees and honey. In the honey, significantly larger residues of captan were found out than maximum residue level (MRL) for this AI – 103.04% MRL. In the case of any AI, the daily intake did not exceed 0.002% acceptable daily intake (ADI).     

新烟碱类农药在我国的登记现状及对蜜蜂的初级风险评估

调研已开发的包括吡虫啉、噻虫嗪、噻虫胺、啶虫脒、噻虫啉、呋虫胺、烯啶虫胺、环氧虫啶、氯噻啉、哌虫啶和氟啶虫胺腈在内的11种新烟碱类农药在我国的登记现状。根据已登记的新烟碱农药的使用方法,开展了不同暴露场景下蜜蜂的初级风险评估。结果表明,喷施场景下,吡虫啉、噻虫嗪、噻虫胺、烯啶虫胺、呋虫胺、氟啶虫胺腈和氯噻啉这7种新烟碱类农药在不同作物上使用对蜜蜂的风险商值均大于1,风险均不可接受;啶虫脒、哌虫啶和噻虫啉在所有登记作物上使用对蜜蜂的风险商值均小于1,风险可接受。土壤或种子处理场景下,除噻虫啉外,其余4种新烟碱类农药包括吡虫啉、噻虫胺、噻虫嗪和呋虫胺对蜜蜂的风险商值均大于1,风险均不可接受。评估结果可为新烟碱类农药在我国的登记管理提供科学参考。     

传粉蜜蜂介导的细菌耐药性传播及其生态与健康风险

目前,抗菌药物的滥用造成了临床和环境中普遍存在的细菌耐药性问题,而细菌耐药性在环境中不断富集和传播扩散会通过食物网对生态安全及人体健康构成威胁。蜜蜂作为最重要的传粉昆虫,在世界各地广泛分布。然而,蜜蜂近年来频繁暴露于抗生素、杀虫剂和杀螨剂等药物,而野外杀虫剂的大量使用被认为是导致世界各地蜜蜂种群数量下降的关键因素。蜜蜂传花授粉的生物学特性使得蜂群与周围环境之间发生频繁的交流,可能导致蜜蜂传粉过程中蜂群与周围环境的交叉污染并发生细菌耐药性的传递。因此,蜜蜂可能成为生态系统中细菌耐药性传播的潜在“帮凶”。传粉蜜蜂介导下的细菌耐药性传播也将对蜂群健康、食品安全乃至生态系统安全构成威胁。本文综合国内外相关研究进展,系统分析了环境污染物暴露对蜜蜂以及蜜蜂肠道耐药基因组的潜在影响,并详细阐述了传粉蜜蜂介导下的细菌耐药性的传播,总结了蜜蜂主要通过蜜蜂-蜜蜂、蜜蜂-植物以及蜜蜂-环境的途径促进细菌耐药性的传播。最后,探讨了蜜蜂介导的细菌耐药性传播对蜂群健康、生态环境以及人体健康的潜在影响。     

杀菌剂对蜜蜂生理和行为的毒性效应研究

杀菌剂在植物病害防治过程中被广泛应用,其在确保粮食安全中具有重要作用。作为重要的经济和授粉昆虫,蜜蜂在传粉过程中不可避免地接触到杀菌剂。含有杀菌剂残留的花蜜和花粉也会被蜜蜂采集进蜂巢,进而影响蜂群的健康和授粉效能。本文从杀菌剂自身及与其他农药的协同作用对蜜蜂毒性、生长发育、生理和行为的影响等方面进行综述,阐述杀菌剂对蜜蜂个体和群体的负面影响,以期为有害生物防治策略制定过程中考虑蜜蜂等授粉昆虫安全,建立并推广蜜蜂授粉与绿色防控增产技术集成应用,并促进我国养蜂业和授粉业的健康可持续发展提供理论依据。     

吡虫啉对蜜蜂幼虫的室内毒性研究

吡虫啉是目前使用最广泛的新烟碱类农药,其不合理使用破坏蜜蜂的嗅觉记忆能力,影响采集行为,导致多种亚致死效应。利用室内人工饲养蜜蜂幼虫技术,选取意大利蜜蜂幼虫为研究对象,经3 d适应性饲养后,连续3 d喂食含不同浓度的吡虫啉日粮,测定蜜蜂幼虫的存活率、化蛹率和羽化率,评估吡虫啉对蜜蜂幼虫生长发育影响。结果表明,吡虫啉处理剂量为15 ng·幼虫^-1时,并不影响蜜蜂幼虫存活率、化蛹率和羽化率;当处理剂量达到150 ng·幼虫^-1时,蜜蜂幼虫羽化率下降,但不影响蜜蜂幼虫的存活率和化蛹率;幼虫7 d半数致死剂量为2 300 ng·幼虫^-1。高剂量吡虫啉对蜜蜂幼虫存活率、化蛹率和羽化率均存在影响,处理剂量越高,存活率、化蛹率和羽化率越低,呈高度负相关(r=-0.99,-0.94,-0.89),同时蜜蜂幼虫的羽化时间延长。研究可为吡虫啉的合理使用提供科学参考。