Visual scanning behaviour in honeybees

Freely flying bees were rewarded with sugar solution on a variety of black-and-white shapes as well as on coloured gratings in various training situations. In subsequent dual-choice tests, the bees' discrimination between the various shapes was measured. In addition, the bees were video-filmed while flying in front of the shapes. The scanning patterns thus obtained were then quantified in order to characterize scanning behaviour and its relationship to the geometrical parameters of the scanned shapes, investigate whether scanning plays a role in pattern discrimination and examine the influence of training on the characteristics of scanning. The scanning patterns clearly mirror the contours of the scanned shape in all cases, i.e. the bees fly along the contours contained in the shape. This behaviour does not depend on whether the scanned shape is one that was previously rewarded, or one that is completely novel to the bees. Comparison of the results of quantifying the scanning patterns with the results of dual-choice tests reveals that scanning behaviour is independent of discrimination performance. On the average, horizontal scanning directions occur more often than vertical directions. Variations of the training situation produce measurable differences in scanning behavior. However, except in the case of vertical scanning on a vertical grating, these differences are quite small, indicating that following contours is a largely stereotyped behaviour. Horizontal gratings are very well discriminated from vertical ones even if they offer contrast to only one receptor type, i.e. blue or green, demonstrating that the direction of contours is visible to the pattern recognition system even under these conditions. However, vertical and horizontal coloured gratings offering only blue-contrast do not elicit contour-following, whereas gratings offering only green-contrast do. Thus, the bees' scanning behaviour is colour-blind and most probably governed by the green receptors. We suggest that contour-following is the by-product of a behavioural mode which serves to prevent retinal image movement during flight in front of a contoured visual pattern.     

The behaviour of queen honeybees and their attendants

Abstract. The behaviour of queen and worker honeybees (Apis mellifera L.) was observed using small colonies in observation hives. Workers paid more attention to queens which had been mated for 2 months or more than to those which were newly mated; virgin queens received least attention. Queens received most attention when they were stationary and least when they were walking over the comb; virgin queens were most active. Queen cells had as many attendants as virgin queens and queen larvae were inspected almost continuously. The queen pheromone component 9–oxo-trans-2–decenoic acid stimulated 'court' behaviour when presented on small polyethylene blocks, but workers responded aggressively to complete extracts of queens' heads. Both the heads and abdomens of mated queens received much attention from court workers but the abdomens were palpated by more workers for longer and were licked much more. The queens' thoraces were least attended. Abdominal tergites posterior to tergite glands were licked for longer than those anterior to the glands. Only worker bees very near to the queen reacted to her and joined her 'court'.
No evidence was found of a diel periodicity in the behaviour of a queen or her 'court'. During the winter the queen's court was smaller than in summer and she walked less and laid fewer eggs. When colonies were fed with sucrose syrup in winter, their queens laid more eggs and workers reared more brood but there was no change in the attention received by the queens.
The implications of these findings for the secretion and distribution of queen pheromones are discussed.     

Development of motor behaviour

The development of motor behaviour depends on the differentiation of underlying circuitry. Recent work with the zebrafish brings the simple swimming behaviour of lower vertebrates and their embryos into focus as a suitable model to study the development of motor circuitry and its genetic control. Changes in connectivity and excitability contribute to the development of swimming in this simple system. In the chick embryo, limb motor circuitry is spontaneously active before motor axons reach their muscle targets, and it has properties in common with the spontaneously active networks in the retina. The early rhythmic activity responsible for embryonic movement is probably a generalised property of developing spinal networks that precedes, and may be required for, the completion of functional locomotor circuitry.     

Six quantitative trait loci influence task thresholds for hygienic behaviour in honeybees (Apis mellifera)

Honeybee hygienic behaviour provides colonies with protection from many pathogens and is an important model system of the genetics of a complex behaviour. It is a textbook example of complex behaviour under simple genetic control: hygienic behaviour consists of two components – uncapping a diseased brood cell, followed by removal of the contents – each of which are thought to be modulated independently by a few loci of medium to large effect. A worker’s genetic propensity to engage in hygienic tasks affects the intensity of the stimulus required before she initiates the behaviour. Genetic diversity within colonies leads to task specialization among workers, with a minority of workers performing the majority of nest‐cleaning tasks. We identify three quantitative trait loci that influence the likelihood that workers will engage in hygienic behaviour and account for up to 30% of the phenotypic variability in hygienic behaviour in our population. Furthermore, we identify two loci that influence the likelihood that a worker will perform uncapping behaviour only, and one locus that influences removal behaviour. We report the first candidate genes associated with engaging in hygienic behaviour, including four genes involved in olfaction, learning and social behaviour, and one gene involved in circadian locomotion. These candidates will allow molecular characterization of this distinctive behavioural mode of disease resistance, as well as providing the opportunity for marker‐assisted selection for this commercially significant trait.     

Estimating the genetic variance of group characters: social behaviour of honeybees (Apis mellifera L.)

Summary A new approach is presented to estimate the genetic variance of social behaviour of groups. Honeybees (Apis mellifera L.) are used as an example for highly social organisms. Most characters of economic importance strongly rely on collective group characters of honeybee colonies. The average relatedness between small groups of workers of one honeybee colony can be estimated using a discrete multinomial distribution. The genetic variance of a social behaviour (alarm behaviour) of groups of honeybee workers is estimated with the intraclass correlation between groups within a colony. In two populations tested, the coefficient of genetic determination was high (0.96–0.98) indicating that the metabolic bio-assay used was only weakly affected by environmental effects.     

The automatic pilot of honeybees

Using scanning harmonic radar, we make visible for the first time the complete trajectories of "goal-vector" flights in honeybees. We demonstrate that bees captured at an established feeding station, and released elsewhere, nevertheless embark on the previously learned vector flight that would have taken them directly home from the station, had they not been artificially displaced. Almost all of the bees maintained accurate compensation for lateral wind drift, and many completed the full length of the vector flight before starting to search for their hive. Our results showed that bees tend to disregard landscape cues during these vector flights, at least initially, and rely on the "optic flow" of the ground beneath them, and their sun compass, to judge both direction and distance.     

蜜蜂对迷宫的学习和记忆

著名的生物学家 Frisch[1] 研究蜜蜂的行为时发现 ,蜜蜂可以从所有其它颜色中区别蓝色 ,说明蜜蜂能够看到作为一种颜色的蓝色 ,并能学会以颜色作为食物的信号。从此 ,揭开了研究蜜蜂学习和记忆的序幕 ,Menzel[2 ] 把蜜蜂作为一个模型系统来研究学习与记忆。长期以来 ,许多生物学家的大量研究发现 :蜜蜂不仅对目标的颜色、模式、气味等有较好的学习和记忆能力 ,而且对陆标以及时间模式等都有较好的学习和记忆能力。然而 ,研究蜜蜂学习迷宫的工作相对比较少 ,Weiss[3] 训练蜜蜂步行通过了相对简单的迷宫 ,Menze[4 ] 在一个 T型迷宫中训练步…     

Sequence learning by honeybees

Bees of several genera make foraging trips on which they visit a series of plants in a fixed order. To help understand how honeybees might acquire such routes, we examined whether (1) bees learn motor sequences, (2) they link motor instructions to visual stimuli, (3) their visual memories are triggered by contextual cues associated with the bees' position in a sequence.

East learns from West: Asiatic honeybees can understand dance language of European honeybees

The honeybee waggle dance, through which foragers advertise the existence and location of a food source to their hive mates, is acknowledged as the only known form of symbolic communication in an invertebrate. However, the suggestion, that different species of honeybee might possess distinct 'dialects' of the waggle dance, remains controversial. Furthermore, it remains unclear whether different species of honeybee can learn from and communicate with each other. This study reports experiments using a mixed-species colony that is composed of the Asiatic bee Apis cerana cerana (Acc), and the European bee Apis mellifera ligustica (Aml). Using video recordings made at an observation hive, we first confirm that Acc and Aml have significantly different dance dialects, even when made to forage in identical environments. When reared in the same colony, these two species are able to communicate with each other: Acc foragers could decode the dances of Aml to successfully locate an indicated food source. We believe that this is the first report of successful symbolic communication between two honeybee species; our study hints at the possibility of social learning between the two honeybee species, and at the existence of a learning component in the honeybee dance language.     

Landmark maps for honeybees

Experiments by Fabre (1915), Thorpe (1950), Chmurzynski (1964), and most recently Gould (1986) suggest that insects have maps of their terrain which enable them to find their way directly to a goal when they are displaced several hundred metres from it. This paper discusses what might constitute an insect's map in terms of a two-part computational model. The first part describes how an insect reaches a goal when the insect is sufficiently close that it can see some of the landmarks which are visible from the goal. The second part considers the problem of navigating when there is no similarity between the view from the release-site and the view from the goal.We start from a model designed to explain how a bee might return to a goal using a two-dimensional snapshot of the landscape seen from the goal (Collett and Cartwright 1983). To guide its return, the model bee continuously compares its snapshot with its current retinal image and moves so as to reduce the discrepancy between the two. Bees can only be guided in the right direction by the difference between current retinal image and snapshot when there is some resemblance between the two. In a realistically cluttered world, snapshot and retinal image become very dis-similar only a short distance from the goal.To increase the distance from which a model bee can return, the bee takes two snapshots at the goal. The first snapshot excludes landmarks near to the goal and the second snapshot includes them. With close landmarks filtered from both snapshot and retinal image, the match between the two deteriorates gradually as the bee moves away from the goal. A model bee using a filtered snapshot and image finds its way back to the neighbourhood of the goal from a relatively long distance (Fig. 2). The bee then switches to the second snapshot and is guided to the precise spot by its memory of the close landmarks.For longer range guidance, the model bee is equipped with an album of snapshots, each taken at a different location within the terrain. Linked to each snapshot is a vector encoding the distance and direction from the place where the snapshot was taken to the hive. When the bee is displaced to a new position, it selects the snapshot which best matches its current image and follows the associated home-vector back to the hive (Fig. 3). Such a hive-centred map can also be used to devise novel routes to places other than the hive. For instance, a bee can reach a foraging site from anywhere in its terrain by adding the home-vector recalled at the starting position to a vector specifying the distance and direction of the foraging site from the hive. The sum of these two vectors defines a direct trajectory to the foraging site.     

Starving honeybees lose self-control

Impulsivity, the widespread preference for a smaller and more immediate reward over a larger and more delayed reward, is known to vary across species, and the metabolic and social hypotheses present contrasting explanations for this variation. However, this presents a paradox for an animal such as the honeybee, which is highly social, yet has a high metabolic rate. We test between these two competing hypotheses by investigating the effect of hunger on impulsivity in bees isolated from their social environment. Using an olfactory conditioning assay, we trained individuals to associate a small and a large reward with or without a delay, and we tested their choice between the two rewards at different levels of starvation. We found an increase in impulsive behaviour and an associated increase in dopamine levels in the brain with increasing starvation. These results suggest that the energetic state of an individual, even in a eusocial group, is a critical driver of impulsivity, and that the social harmony of a group can be threatened when the energetic states of the group members are in conflict.     

Development of eliminative behaviour in piglets

The development of eliminative behaviour in piglets was followed by watching piglets from the day of birth through to 5 weeks of age. Two different environments were used to establish the role of the sow. Six-day-old piglets consistently voided outside their lying area. The sow played no part in influencing where a piglet eliminated. Siblings also did not influence another piglet. When the lying area of the piglets was experimentally fouled, the lying behaviour of the piglets was disrupted. It was concluded that piglets dislike some property(s) of soiled bedding and so avoid soiling their lying area. The conclusion that piglets avoid eliminating in their lying area is contrasted with suggestions that piglets have a preferred elimination site.