Application of Artificial Bee Colony Algorithm to Maximum Likelihood DOA Estimation

Maximum Likelihood (ML) method has an excellent performance for Direction-Of-Arrival (DOA) estimation, but a multidimensional nonlinear solution search is required which complicates the computation and prevents the method from practical use. To reduce the high computational burden of ML method and make it more suitable to engineering applications, we apply the Artificial Bee Colony (ABC) algorithm to maximize the likelihood function for DOA estimation. As a recently proposed bio-inspired computing algorithm, ABC algorithm is originally used to optimize multivariable functions by imitating the behavior of bee colony finding excellent nectar sources in the nature environment. It offers an excellent alternative to the conventional methods in ML-DOA estimation. The performance of ABC-based ML and other popular meta-heuristic-based ML methods for DOA estimation are compared for various scenarios of convergence, Signal-to-Noise Ratio (SNR), and number of iterations. The computation loads of ABC-based ML and the conventional ML methods for DOA estimation are also investigated. Simulation results demonstrate that the proposed ABC based method is more efficient in computation and statistical performance than other ML-based DOA estimation methods.     

Changes in weight of the pharyngeal gland and haemolymph titres of juvenile hormone,protein and vitellogenin in worker honey bees

Four physiological parameters (haemolymph-juvenile hormone titre, protein concentration, vitellogenin concentration, and pharyngeal gland dry weight) were examined in the following categories of queenright adult worker bees: summer bees 1–40 days old, winter bees 80–130 days old, 12–100-day old bees at the beginning of winter, 100–195-day old bees at the end of winter, and 1–100-day old bees experimentally induced to live longer in summer.In contrast to the continuously increasing titre of juvenile hormone in ageing summer bees, winter bees kept a constant low level. In bees at the beginning of winter, the hormone titre never reached high values. However, at the end of winter it rose from a low to a high level, comparable with the high titre of 24–40-day old summer bees. In experimentally induced longlived bees in summer, the juvenile hormone titre did not increase as in normal summer bees but remained low as in bees at the beginning of winter. Among the known natural juvenile hormones, only juvenile hormone III was present in the haemolymph of winter bees.The results support the hypothesis of polyphenism being regulated by the titre of juvenile hormone in the haemolymph.     

澜沧江流域北部中华蜜蜂有毒蜂蜜孢粉学和营养生态位分析

为分析澜沧江流域北部人食用蜂蜜中毒的原因,于2013年6—9月份,对该区域蜜蜂和蜜源植物的分布情况进行了调查,观察蜜蜂采集有毒蜜源植物的行为,并进一步调查了蜜蜂巢内蜂蜜、蜂花粉的储存情况,采集了中华蜜蜂蜂蜜样品,进行蜂蜜孢粉学与营养生态位分析。该区域有大量采用传统方式进行人工饲养的中华蜜蜂(Apis cerana cerana),及少量野生中华蜜蜂、黑色小蜜蜂(Apis audreniformis)、黑色大蜜蜂(Apis laboriosa smith)群体分布;人工饲养的中华蜜蜂蜂巢内部结构与野生中华蜜蜂蜂巢相似,为自然蜂巢,内有充足的蜜粉储存,部分蜂群蜂巢内虫害严重。该区域内主要蜜源植物为荞麦(Fagopyrum esculentum Moench),其他零星辅助蜜源较多,部分地点南烛(Vaccinium bracteatum Thunb)、昆明山海棠(Tripterygium hypoglaucum(Levl.)Hutch)连片集中分布。对中华蜜蜂蜂蜜进行孢粉学和营养生态位分析,结果表明:中华蜜蜂蜂蜜标本中含有有毒蜜源植物南烛、昆明山海棠花粉,部分样品中南烛、昆明山海棠的花粉含所占比例较高;中华蜜蜂的营养生态位宽度为0.22,比其他地区中华蜜蜂生态位指数小,推测澜沧江水电枢纽的修建等人为原因已对蜜蜂种类、蜜源植物的物种组成、群落结构造成了较大影响。     

Antimicrobial activities of Saudi honey against Pseudomonas aeruginosa

Five types of imported and local honey were screened for both their bacteriocidal/bacteriostatic activities against both Imipenem resistant and sensitive Pseudomonas aeruginosa in both Brain Heart infusion broth and Mueller–Hinton agar. The results indicated that the effect was concentration and type of honey dependant. All types of honey tested exerted a full inhibition of bacterial growth at the highest concentration tested of 50% at 24 h of contact. The inhibitory effect of honey on bacterial growth was clear with concentrations of 20% and 10% and this effect was most evident in the case of Manuka honey as compared to Nigella sativa honey and Seder honey. Manuka honey UMF +20 showed a bacteriocidal activity on both Imipenem resistant and sensitive P. aeruginosa, while Seder honey and N. sativa honey exerted only a bacteriostatic effect. Manuka honey UMF +10 showed most effect on antimicrobial resistance. Manuka honey UMF +10 had an effect on modulation of Imipenem resistant P. aeruginosa. Conclusion: The results indicated that various types of honey affected the test organisms differently. Modulation of antimicrobial resistance was seen in the case Manuka honey UMF +10.     

蜜蜂上颚腺及其分泌物研究进展

上颚腺是蜜蜂重要的外分泌腺体,其分泌物是维系蜂群社会性结构的重要物质。蜂王和工蜂上颚腺分泌物合成均以硬脂酸为合成前体,但在脂肪酸的β-氧化过程中表现出级型差异性,导致分泌物组分比例不同。蜂王上颚腺分泌物以9-羰基-2癸烯酸(9-ODA)为主,有吸引工蜂和雄蜂、抑制工蜂卵巢发育等作用;工蜂上颚腺分泌物以10-羟基-2癸烯酸(10-HDA)和10-羟基癸酸(10-HDAA)为主,是蜂王浆的重要组成部分。同时,这种具备典型级型差异的分泌物组成又具有级型间可塑性,在不同蜂种间也存在区别。近年来在转录水平和蛋白水平的一些研究进一步揭示了级型间差异的分子基础。针对蜜蜂上颚腺及其分泌物的研究在蜜蜂生物学、行为学和蜂产品质量控制等方面具有重要的意义。本文通过总结国内外相关研究进展,旨在为上颚腺分泌物的作用机制、生物合成机制等领域的进一步深入研究提供借鉴。     

蜜蜂寿命可塑性研究进展

蜜蜂是一种完全社会化的昆虫,它们在寿命方面表现出了显著的级型差异.蜂王的平均寿命是1～2年,而工蜂在生产季节平均寿命是30～40 d,越冬季节平均寿命是90～200d,显然蜜蜂寿命有可塑性.这种可塑性是由环境因素控制,因为蜂王和工蜂的遗传基础是一致的.另外工蜂任务可以发生逆转,这意味着老化的逆转.本文综述了近年来一些老...     

Reduced‐risk insecticides in Neotropical stingless bee species: impact on survival and activity

As honeybees are the main pollinator subject to an intense research regarding effects of pesticides, other ecologically important native bee pollinators have received little attention in ecotoxicology and risk assessment of pesticides in general, and insecticides in particular, some of which are perceived as reduced‐risk compounds. Here, the impact of three reduced‐risk insecticides – azadirachtin, spinosad and chlorantraniliprole – was assessed in two species of stingless bees, Partamona helleri and Scaptotrigona xanthotrica, which are important native pollinators in Neotropical America. The neonicotinoid imidacloprid was used as a positive control. Spinosad exhibited high oral and contact toxicities in adult workers of both species at the recommended label rates, with median survival times (LT₅₀s) ranging from 1 to 4 h, whereas these estimates were below 15 min for imidacloprid. Azadirachtin and chlorantraniliprole exhibited low toxicity at the recommended label rates, with negligible mortality that did not allow LT₅₀ estimation. Sublethal behavioural assessments of these two insecticides indicated that neither one of them affected the overall group activity of workers of the two species. However, both azadirachtin and chlorantraniliprole impaired individual flight take‐off of P. helleri and S. xanthotrica worker bees, which may compromise foraging activity, potentially leading to reduced colony survival. These findings challenge the common perception of non‐target safety of reduced‐risk insecticides and bioinsecticides, particularly regarding native pollinator species.     

Effectiveness of honey bees in delivering the biocontrol agent Bacillus subtilis to blueberry flowers to suppress mummy berry disease

Honey bees are important pollinators of commercial blueberries in the southeastern United States, and blueberry producers often use supplemental bees to achieve adequate fruit set. However, honey bees also vector the plant pathogenic fungus Monilinia vaccinii-corymbosi which infects open blueberry flowers through the gynoecial pathway causing mummy berry disease. Here, we report the results of a 3-year field study to test the hypothesis that using bee hives equipped with dispensers containing the biocontrol product Serenade, a commercial formulation of the bacterium Bacillus subtilis which has shown activity against flower infection by M. vaccinii-corymbosi in laboratory experiments, can reduce mummy berry disease incidence when honey bees are used as pollinators in blueberries. Individual honey bees carried 5.1–6.4 × 10⁵ colony-forming units (CFU) of B. subtilis when exiting hive-mounted dispensers with Serenade. On caged rabbiteye blueberry bushes in the field, population densities of B. subtilis vectored by honey bees reached a carrying capacity of <10³ CFU per flower stigma within 2 days of exposure, and there was a highly significant non-linear relationship between B. subtilis populations per stigma and bee activity, expressed as number of legitimate flower visits per time interval per cage (R = 0.6928, P < 0.0001, n = 32). Honey bee density (1600 or 6400 individuals per 5.8-m³ cage) and Serenade treatment (presence or absence of the product in hive-mounted dispensers) significantly (P < 0.05) affected the incidence of fruit mummification on caged bushes, whereby increasing bee density increased disease incidence and application of Serenade reduced disease levels. Taken together, results of this study suggest that use of a hive-dispersed biocontrol product such as Serenade as a supplement during pollination can reduce the risk of mummy berry disease. This may be a prudent practice that optimizes the benefits to pollination of high bee densities while reducing the associated disease-vectoring risk.     

Antennal sucrose perception in the honey bee (Apis mellifera L.): behaviour and electrophysiology

Physiological mechanisms of antennal sucrose perception in the honey bee were analysed using behavioural and electrophysiological methods. Following sucrose stimulation of the tip of a freely moving antenna, the latency of proboscis extension was 320–340 ms, 80–100 ms after the first activity in muscle M17 controlling this response. When bees were allowed to actively touch a sucrose droplet with one antenna, contacts with the solution were frequent with durations of 10–20 ms and average intervals between contacts of approximately 40 ms. High sucrose concentrations led to short and frequent contacts. The proboscis response and M17 activity were largely independent of stimulus duration and temporal pattern. Taste hairs of the antennal tip displayed spike responses to sucrose concentrations down to at least 0.1%. The first 25 ms of the response were suitable for discrimination of sucrose concentrations. This time interval corresponds to the duration of naturally occurring gustatory stimuli. Sucrose responses between different hairs on the same antenna showed a high degree of variability, ranging from less than five to over 40 spikes per 0.5 s for a stimulus of 0.1% sucrose. This variability of receptor responses extends the dynamic range of sucrose perception over a large range of concentrations.