The optomotor yaw response of the desert locust, Schistocerca gregaria

Abstract The optomotor yaw response of the desert locust, Schistocerca gregaria (Forsk.), was investigated under open- and closed-loop conditions. When flying tethered in the centre of a vertically striped hollow sphere, the polarity of response of the locust was always the same as the stimulus. The response, therefore, appears suitable to stabilize body posture against passive rotations around the yaw-axis in free flight. Responses were induced by contrast frequencies up to 150 Hz with a maximum of amplitude at about 20 Hz. The characteristic curve, measured between 0.3 and 160 Hz, is widened up towards higher frequencies as compared with those of bees and flies.
Variability was the most striking feature in the locust's yaw response. The amplitude of modulation not only varied greatly between individuals but also changed with the same visual stimulus in the course of an experiment. We therefore suppose that the locust's turning behaviour is subject to gain control mechanisms and that spontaneous gain modulations are responsible for the observed variability in the stimulus-response conversion.     

What the honeybee sees: a review of the recognition system of Apis mellifera

Abstract. For many years, two opposing theories have dominated our ideas of what honeybees see. The earliest proposal based on training experiments was that bees detected only simple attributes or features, irrespective of the actual pattern. The features demonstrated experimentally before 1940 were the disruption of the pattern (related to spatial frequency), the area of black or colour, the length of edge, and the angle of orientation of a bar or grating. Cues discovered recently are the range, and radial and tangential edges, and symmetry, relative to the fixation point, which is usually the reward hole. This theory could not explain why recognition failed when the pattern was moved. In the second theory, proposed in 1969, the bee detected the retinotopic directions of black or coloured areas, and estimated the areas of overlap and nonoverlap on each test pattern with the corresponding positions in the training pattern. This proposal explained the progressive loss of recognition as a test pattern was moved or reduced in size, but required that the bees saw and remembered the layout of every learned pattern and calculated the mismatch with each test image. Even so, the same measure of the mismatch was given by many test patterns and could not detect a pattern uniquely. Moreover, this theory could not explain the abundant evidence of simple feature detectors. Recent work has shown that bees learn one or more of a limited number of simple cues. A newly discovered cue is the position, mainly in the vertical direction, of the common centre (centroid) of black areas combined together. Significantly, however, the trained bees look for the cues mentioned above only in the range of places where they had occurred during the training. These two observations made possible a synthesis of both theories. There is no experimental evidence that the bees detect or re-assemble the layout of patterns in space; instead, they look for a cue in the expected place. With an array of detectors of the known cues, together with their directions, this mechanism would enable bees to recognize each familiar place from the coincidences of cues in different directions around the head.     

Two-dimensional pattern discrimination by the honeybee

For a reward of sugar, bees will learn to prefer a pattern rather than an alternative similar one. This visual discrimination allows us to measure resolution, and to search for the cues that the bees remember and later use to recognize the rewarded pattern. Two systems in parallel, analogous to low pass and high pass filters, are distinguished. The first system discriminates the location and size of at least one area of contrast on each side of the target, with inputs from blue and green receptors, but the ability to discriminate the location of colour depends upon fixation. The bees remember less than a low resolution copy of the image, even when they fixate on a vertical pattern. The second system amplifies the contrast at edges in the pattern, ignoring the direction of contrast, and controls fixation upon the target. Edges are discriminated according to their orientation and radial or tangential arrangement. An axis of bilateral symmetry is detected. However, the relative locations of cues within the image are lost, apparently because the relevant neurones have very large fields. Only the cues, not the whole patterns, are preserved in memory. This system is colour blind because its input is restricted to the receptors with peak sensitivity in the green. The two systems together discriminate many simple patterns, but not all, because the filters are limited in variety.     

农药对蜜蜂行为的影响

农药对蜜蜂的安全性评价包括在实验室以及更高层次的半大田和大田水平上的研究。蜜蜂行为是蜜蜂机体是否正常的直接表现,因此也是安全性评价的重要指标。文章概述农药对蜜蜂行为的影响,包括蜂王产卵行为,工蜂分工、采集行为、同群和外群工蜂辨别、学习行为和农药对蜜蜂的驱避性。     

Role of hydrocarbons in egg recognition in the honeybee

Abstract. Despite worker‐laid and queen‐laid honeybee eggs having significantly different hydrocarbon profiles, bioassays and chemical supplementation studies show that changing the hydrocarbon profile does not affect egg identity. Furthermore, full‐sized eggs that are tested just before being laid or just after being laid have similar hydrocarbon patterns but are treated differently in egg‐discrimination bioassays with only the laid eggs surviving. This suggests that hydrocarbons play no role in the egg‐recognition system in honeybees.     

Visual discrimination by the honeybee (Apis mellifera): the position of the common centre as the cue

Abstract. Bees can be trained to discriminate between a target with a 20° spot above a 10° spot of the same colour, and another target with the spots exchanged in position. Tests show that they do not remember the separate positions of spots of the same colour (including black) on the same target. The bees discriminate the difference in positions, in the vertical direction, of the common centres of the spots taken together, with or without green contrast.
Similar results are obtained in discriminations of a fixed T shape, each composed of two broad black bars subtending 8 by 24°, vs the same shape inverted. The trained bees fail to discriminate between the T shapes when the centroids are at the same level in the vertical direction. Moving the shapes in the horizontal direction in tests has less effect. Quite different results are obtained when the two bars of the T shape differ in colour. The bees discriminate the positions of the two colours separately, but they still fail to discriminate the shape of the T. The results can be explained by filters that detect the intensities within their fields, irrespective of shape, and weigh them according to their vertical angles from the horizontal midline. The normal function of these filters could be to detect the levels of objects relative to the horizon when the bee is in flight.     

Conserving genetic diversity in the honeybee: Comments on Harpur et al. (2012)

The article by Harpur et al. (2012) ‘Management increases genetic diversity of honey bees via admixture’ concludes that ‘…honey bees do not suffer from reduced genetic diversity caused by management and, consequently, that reduced genetic diversity is probably not contributing to declines of managed Apis mellifera populations’. In the light of current honeybee and beekeeping declines and their consequences for honeybee conservation and the pollination services they provide, we would like to express our concern about the conclusions drawn from the results of Harpur et al. (2012). While many honeybee management practices do not imply admixture, we are convinced that the large-scale genetic homogenization of admixed populations could drive the loss of valuable local adaptations. We also point out that the authors did not account for the extensive gene flow that occurs between managed and wild/feral honeybee populations and raise concerns about the data set used. Finally, we caution against underestimating the importance of genetic diversity for honeybee colonies and highlight the importance of promoting the use of endemic honeybee subspecies in apiculture.     

狄斯瓦螨和蜜蜂病毒对意大利蜜蜂蜂群越冬的影响

越冬期是蜂群损失最主要的阶段.通过比较分析45个意大利蜜蜂Apis mellifera ligustica蜂群在繁殖越冬蜂前的狄斯瓦螨Varroa destructor寄生率和病毒感染情况、越冬表现及越冬期存活蜂群的病毒感染情况等,探究与越冬期蜜蜂健康紧密相关的影响因素.结果表明,繁殖越冬蜂前蜂群的狄斯瓦螨寄生率与蜜蜂...     

Exceptionally high density of NUMTs in the honeybee genome

The available genome sequences of 4 insects (the fruit fly, the African malaria mosquito, the flour beetle, and the honeybee) are used to compare the amount of mitochondrial DNA transferred to the nuclear genome (NUMTs). The data from the beetle and the bee show frequent transfer of NUMTs, whereas NUMTs in the 2 other insects are rare. The density of NUMTs in the honeybee (>1.0 bp transferred DNA per 1 kb of the nuclear sequence) is the highest in any animal studied, about ten times higher than in humans and comparable to the densities in plant genomes. The density of NUMTs in the beetle (0.056 bp/kb) is of the same order of magnitude as that in humans. The analysis of the honeybee genome indicates that NUMTs originate from all parts of the mitochondrial genome, that about two-thirds of the nuclear copies result from secondary transpositions within the nuclear genome, that the copies are significantly associated to "mariner" type transposons, and that the NUMTs consist mainly of short and fragmented copies.     

蜜蜂蜂王与工蜂级型分化研究进展

蜜蜂ApismekiferaL .是典型的社会性昆虫 ,蜂王和工蜂都是由受精卵发育而来的二倍体成蜂 ,但是在形态、生理、行为等方面有明显的差异 ,属于不同的级型。蜂王和工蜂的级型分化的关键时期发生在幼虫的 4龄末至 5龄止。分化是由分化基因调控的 ,幼虫期食物的质和量是分化的外部决定因子。JH对两级型中卵巢的分化有非常重要的调控作用。蜜蜂脑或其它组织中可能有分泌调控CA的咽侧体调节激素 ,它们通过对CA中JH的合成和分泌的调控而参与了分化的调控。章鱼胺等生物胺也参与了分化调控过程。     

Effect of triflumuron on brood development and colony survival of free-flying honeybee, Apis mellifera L.

Abstract:  The effect of the insect growth regulator (IGR) triflumuron (Alsystin^® 25 WP) on honeybee, Apis mellifera L. (Hym., Apidae), was studied in a semi-field test. Free-living colonies were fed one litre per hive of sucrose syrup containing 0, 0.025, 0.25 or 2.5 g of triflumuron. A significant reduction in flight activity was noted 6–10 weeks post-treatment at the two higher doses. These colonies reared less brood than before treatment. While the comb area occupied by uncapped brood was as high as [0.025 and 0.25 g active ingredient (a.i.)] or higher (2.5 g a.i.) than before treatment, there was a significant decline in capped brood at the two higher doses, indicating enhanced larval mortality. No capped brood was reared in the hive treated at the highest dose from 3–9 weeks post-treatment. Yet there was a significant accumulation of pollen and honey in the brood compartment at all doses. All colonies except the one treated at the highest dose survived the following winter. However, at 43 weeks post-treatment, hives treated at intermediate and low doses showed a significant increase in uncapped brood and a significant decrease in capped brood. This study revealed a strong residual toxicity of triflumuron to brood and substantiated its classification as hazardous to honeybee.     

Variable microsatellite loci isolated from the Asian honeybee, Apis cerana (Hymenoptera; Apidae)

We developed 12 polymorphic microsatellite loci for the Asian honeybee, Apis cerana using the magnetic particle method. Eight of these 12 were highly polymorphic, having four to seven alleles with an expected heterozygosity of 0.38 to 0.78. The primers also produce polymorphic products in related honeybee species such as Apis nigrocincta. These loci can be used to study parameters associated with genetic structure, such as paternity frequency and worker reproduction.     

Post‐ingestive effect of plant phenolics on the feeding behaviour of the honeybee Apis cerana

As the staple food of honey bees, honey is rich in plant phenolics derived from pollen, nectar and resin. Most studies concentrate on the temporary response of bees' peripheral chemoreceptors to these chemicals, and the post‐ingestive effects of plant phenolics are largely ignored. In the present study, a series of feeding experiments are conducted to test whether plant phenolics modulate the response thresholds and rhythmic behaviour of the honeybee Apis cerana (Ruttner). The results of the study demonstrate that bees fed with syrup containing high concentrations of phenlics reduce their response thresholds greatly, and shift their feeding rhythms significantly. Because the forager response thresholds determine their foraging choice, and their rhythmic behaviour is required for timing visits to flowers, enhanced plant phenolics as a result of global environment change may change the bees' pollination service in our changing world.     

Male fitness of honeybee colonies (Apis mellifera L.)

Honeybees (Apis mellifera L.) have an extreme polyandrous mating system. Worker offspring of 19 naturally mated queens was genotyped with DNA microsatellites, to estimate male reproductive success of 16 drone producing colonies. This allowed for estimating the male mating success on both the colony level and the level of individual drones. The experiment was conducted in a closed population on an isolated island to exclude interferences of drones from unknown colonies. Although all colonies had produced similar numbers of drones, differences among the colonies in male mating success exceeded one order of magnitude. These differences were enhanced by the siring success of individual drones within the offspring of mated queens. The siring success of individual drones was correlated with the mating frequency at the colony level. Thus more successful colonies not only produced drones with a higher chance of mating, but also with a significantly higher proportion of offspring sired than drones from less successful colonies. Although the life cycle of honeybee colonies is very female centred, the male reproductive success appears to be a major driver of natural selection in honeybees.     

The POL area of the honey bee's eye: behavioural evidence

ABSTRACT. The uppermost dorsal part of the honey bee's compound eye contains a group of c. 150 specialized ommatidia. The photoreceptors of these ommatidia are characterized by a number of anatomical and physiological peculiarities which suggest that they have functional significance for the detection of polarized skylight. Here, we show by painting out different parts of the eye and recording the bee's behavioural responses that the specialized photoreceptors at the dorsal margin of the eye are indeed necessary for detecting polarized skylight and deriving compass information from celestial e-vector patterns. Hence, this group of specialized ommatidia can be called the POL area of the bee's compound eye.     

Social parasitism by honeybee workers (Apis mellifera capensis Escholtz): host finding and resistance of hybrid host colonies

We studied possible host finding and resistance mechanisms ofhost colonies in the context of social parasitism by Cape honeybee(Apis mellifera capensis) workers. Workers often join neighboringcolonies by drifting, but long-range drifting (dispersal) tocolonies far away from the maternal nests also rarely occurs.We tested the impact of queenstate and taxon of mother andhost colonies on drifting and dispersing of workers and on the hosting of these workers in A. m. capensis, A. m. scutellata,and their natural hybrids. Workers were paint-marked accordingto colony and reintroduced into their queenright or queenlessmother colonies. After 10 days, 579 out of 12,034 labeled workerswere recaptured in foreign colonies. We found that driftingand dispersing represent different behaviors, which were differentlyaffected by taxon and queenstate of both mother and host colonies.Hybrid workers drifted more often than A. m. capensis and A.m. scutellata. However, A. m. capensis workers dispersed moreoften than A. m. scutellata and the hybrids combined, and A. m. scutellata workers also dispersed more frequently than thehybrids. Dispersers from queenright A. m. capensis colonieswere more often found in queenless host colonies and vice versa,indicating active host searching and/or a queenstate-discriminatingguarding mechanism. Our data show that A. m. capensis workersdisperse significantly more often than other races of A. mellifera,suggesting that dispersing represents a host finding mechanism.The lack of dispersal in hybrids and different hosting mechanismsof foreign workers by hybrid colonies may also be responsiblefor the stability of the natural hybrid zone between A. m.capensis and A. m. scutellata.     

The ocelli control the flight course in honeybees

Abstract Fully-sighted honeybees and bees with all ocelli occluded were trained to fly through an arena to arrive at a feeding place. After training, the bees were exposed to side-light flashes during their feeding flights. The flight paths were recorded on video and analysed frame by frame at 40 ms intervals with reference to the main parameters, the coordinates of the thorax and the yaw angle of the bee. Course angles, translational course velocities and accelerations were calculated, and the responses to side light flashes evaluated with respect to 'on' and 'off.
Immediately after light on, fully-sighted bees respond slightly positively by yawing and flying toward the side light. Bees in which all ocelli are occluded are greatly disturbed and respond with negative yawing and flight path directions.
The ocelli apparently help to control phototactic alertness in the bee. They determine whether phototactic orienting or pattern-induced orienting behaviour is more important in a particular state of motivation. They help to minimize the level of disturbance in flight course control, obviously by activating a neuronal circuit with comparator attributes. It is assumed that this kind of compensation or suppression of phototactically guided reflexes occurs only for a few 100 ms. Consequently, the biological significance of light flashes shorter than 400 ms is very slight.
Fully-sighted bees decelerate strongly when a side light is switched on. Bees in which the ocelli are occluded behave less cautiously: they generally fly faster and need more reaction time. Thus, the ocelli help the bee to react photokinetically to photic stimuli in a much shorter time than do the compound eyes alone.