Communication In Bees Research Articles

Communication among animals and bioacoustics studies on bees.

The communication of honey bees encompasses diverse forms, focusing on signals that resemble those in the learning process. Bioacoustics plays a crucial role in understanding this phenomenon, especially in the context of social insects, where communicative coding is complex and essential for survival. In this article, various aspects of bee communication are analyzed, examining both acoustics and other forms of information transmission. In the bee family, there are several communication mechanisms, such as the dance of bees, vibrations, buzzing, and singing. The dance communication of honey bees, based on dance movements, dates back as far as 40 million years, making it older than human language. This form of communication is linked to environmental needs and determines the survival of bees. Signals from queen bees are associated with reproductive needs within the colony, and other individuals exhibit diverse sound characteristics. Different species of bees utilize various aspects of the environment for communication, including gravity and the position of the sun. The precision of transmitted signals may depend on the distance to a food source or potential threat. Sounds emitted by bees serve diverse functions, such as deterring predators or recruiting other individuals for food collection. Modern technologies, especially bioacoustics, enable more precise studies of bee communication. Advanced methods of vibrational spectrum analysis even allow the prediction of swarming with high effectiveness, which can be particularly useful in beekeeping practices. Studies on the bioacoustic hive, utilizing stereo microphones and soundproofing, indicate the potential of these technologies for a better understanding of bee communication in natural conditions. However, many aspects of bee communication still require more detailed research, such as the role of honey-filled cells in transmitting vibrations, necessitating the use of precise tools and technologies. The bioacoustic hive project, based on traditional bee frames, provides new insights into bee communication, especially concerning sounds generated during bee collisions within the hive. Conclusions from bioacoustic studies have significant practical potential in apiculture. The use of stereo microphones and soundproofing improves the perception and assessment of acoustic phenomena within the hive. Prospects for utilizing sound recorders for continuous monitoring of life inside the hive, and the assessment of zoo-hygienic conditions, underscore the growing importance of bioacoustics in beekeeping practices. These discoveries open new perspectives for research into the social life of these crucial insect species and their conservation.

Real-time swarming detection in honeybees: Leveraging audio signal processing and machine learning techniques

Acoustical signals play a significant role in honey bee communication across various behavioral contexts. One notable example is queen piping, which refers to the acoustic signals emitted by young queens during the swarming process. Specifically, emerged virgin queens emit a distinct acoustic signal known as “tooting.” Tooting signals typically consist of one or two pulses lasting approximately one second, characterized by an initial rise in both amplitude and frequency. Recognizing these signals is of utmost importance for beekeepers as it enables them to identify an imminent swarm, effectively manage the swarming process, and safeguard the colony. This paper proposes a novel method for online swarming detection in honey bees, leveraging audio signal collection, acoustical signal processing, and machine learning techniques. The experimental results demonstrate the effectiveness of the proposed system in accurately detecting swarming at its early stages. Notably, the system maintains a high level of accuracy even when confronted with environmental noise and other unfamiliar audio signals that could potentially corrupt the audio signal acquired from the beehive.

Diverse communication strategies in bees as a window into adaptations to an unpredictable world

Communication is a fundamental feature of animal societies and helps their members to solve the challenges they encounter, from exploiting food sources to fighting enemies or finding a new home. Eusocial bees inhabit a wide range of environments and they have evolved a multitude of communication signals that help them exploit resources in their environment efficiently. We highlight recent advances in our understanding of bee communication strategies and discuss how variation in social biology, such as colony size or nesting habits, and ecological conditions are important drivers of variation in communication strategies. Anthropogenic factors, such as habitat conversion, climate change, or the use of agrochemicals, are changing the world bees inhabit, and it is becoming clear that this affects communication both directly and indirectly, for example by affecting food source availability, social interactions among nestmates, and cognitive functions. Whether and how bees adapt their foraging and communication strategies to these changes represents a new frontier in bee behavioral and conservation research.

Neuroethology: Perceived danger inhibits the wanting system of bees

A dopaminergic wanting system drives foraging in honey bees. A new study shows that encounters with the Asian hornet, a fierce bee predator, decrease brain dopamine levels and thus foraging. Stop signals, used to terminate the waggle dances of receivers, have the same effect, showing the power of bee communication.

Function of environment-derived male perfumes in orchid bees

Perfume making in male orchid bees is a unique behavior that has given rise to an entire pollination syndrome in the neotropics.1,2 Male orchid bees concoct and store species-specific perfume mixtures in specialized hind-leg pockets3 using volatiles acquired from multiple environmental sources, including orchid flowers.4,5 However, the function and the ultimate causes of this behavior have remained elusive.2,6 Although previous observations suggested that male perfumes serve as chemical signals, the attractiveness for females has not be shown.7,8 Here, we demonstrate that the possession of perfume increases male mating success and paternity in Euglossa dilemma, a species of orchid bees recently naturalized in Florida. We supplemented males reared from trap-nests with perfume loads harvested from wild conspecifics. In dual-choice experiments, males supplemented with perfumes mated with more females, and sired more offspring, than untreated, equal-aged, control males. Although perfume supplementation had little effect on the intensity of male courtship display, it changed the dynamics of male-male interactions. Our results demonstrate that male-acquired perfumes are sexual signals that stimulate females for mating and suggest that sexual selection is key in shaping the evolution of perfume communication in orchid bees.

Hive geometry shapes the recruitment rate of honeybee colonies.

Honey bees make decisions regarding foraging and nest-site selection in groups ranging from hundreds to thousands of individuals. To effectively make these decisions, bees need to communicate within a spatially distributed group. However, the spatiotemporal dynamics of honey bee communication have been mostly overlooked in models of collective decisions, focusing primarily on mean field models of opinion dynamics. We analyze how the spatial properties of the nest or hive, and the movement of individuals with different belief states (uncommitted or committed) therein affect the rate of information transmission using spatially-extended models of collective decision-making within a hive. Honeybees waggle-dance to recruit conspecifics with an intensity that is a threshold nonlinear function of the waggler concentration. Our models range from treating the hive as a chain of discrete patches to a continuous line (long narrow hive). The combination of population-thresholded recruitment and compartmentalized populations generates tradeoffs between rapid information propagation with strong population dispersal and recruitment failures resulting from excessive population diffusion and also creates an effective colony-level signal-detection mechanism whereby recruitment to low quality objectives is blocked.

Effects of Synthetic Acaricides and Nosema ceranae (Microsporidia: Nosematidae) on Molecules Associated with Chemical Communication and Recognition in Honey Bees.

Acaricides and the gut parasite Nosema ceranae are commonly present in most productive hives. Those stressors could be affecting key semiochemicals, which act as homeostasis regulators in Apis mellifera colonies, such as cuticular hydrocarbons (CHC) involved in social recognition and ethyl oleate (EO) which plays a role as primer pheromone in honey bees. Here we test the effect of amitraz, coumaphos, tau-fluvalinate and flumethrin, commonly applied to treat varroosis, on honey bee survival time, rate of food consumption, CHC profiles and EO production on N. ceranae-infected and non-infected honey bees. Different sublethal concentrations of amitraz, coumaphos, tau-fluvalinate and flumethrin were administered chronically in a syrup-based diet. After treatment, purified hole-body extracts were analyzed by gas chromatography coupled to mass spectrometry. While N. ceranae infection was also shown to decrease EO production affecting survival rates, acaricides showed no significant effect on this pheromone. As for the CHC, we found no changes in relation to the health status or consumption of acaricides. This absence of alteration in EO or CHC as response to acaricides ingestion or in combination with N. ceranae, suggests that worker honey bees exposed to those highly ubiquitous drugs are hardly differentiated by nest-mates. Having determined a synergic effect on mortality in worker bees exposed to coumaphos and Nosema infection but also, alterations in EO production as a response to N. ceranae infection it is an interesting clue to deeper understand the effects of parasite-host-pesticide interaction on colony functioning.

Detrimental effects of clothianidin on foraging and dance communication in honey bees.

Ongoing losses of pollinators are of significant international concern because of the essential role they have in our ecosystem, agriculture, and economy. Both chemical and non-chemical stressors have been implicated as possible contributors to their decline, but the increasing use of neonicotinoid insecticides has recently emerged as particularly concerning. In this study, honey bees were exposed orally to sublethal doses of the neonicotinoid clothianidin in the field in order to assess its effects on the foraging behavior, homing success, and dance communication. The foraging span and foraging activity at the contaminated feeder decreased significantly due to chronic exposure at field-realistic concentrations. Electrostatic field of dancing bees was measured and it was revealed that the number of waggle runs, the fanning time and the number of stop signals were significantly lower in the exposed colony. No difference was found in the homing success and the flight duration between control and treated bees released at a novel location within the explored area. However, a negative effect of the ambient temperature, and an influence of the location of the trained feeder was found. Finally, the residues of clothianidin accumulated in the abdomens of exposed foraging bees over time. These results show the adverse effects of a chronic exposure to sublethal doses of clothianidin on foraging and dance communication in honey bees.

The influence of available comb storage space on the performance of honey bee communication signals that regulate foraging

Numerous activities within honey bee (Apis mellifera L.) colonies rely on feedback loops for organization at the group level. Many of the processes associated with the feedback loops organizing a honey bee colony’s activities are in striking parallel to other systems, such as intercellular interactions involved in motor neuron function, and principles derived from their study can be applied to these diverse fields, among others. This study looked at the communication signals honey bees employ while provisioning their nest with food to assess whether or not the bees use signals when their hive has no more available storage space. In this experiment, the storage space was alternated each day between no available space and ample space. The communication signals used by the bees were counted during each treatment and compared. When the hive had no storage space available, significantly more stop signals, which inhibit foraging, and tremble dances, which recruit more bees to unload incoming foragers, were observed. This suggests that the bees had noted the absence of storage space and were modifying their communication accordingly.

Behavioural, physiological and molecular changes in alloparental caregivers may be responsible for selection response for female reproductive investment in honey bees.

Reproductive investment is a central life history variable that influences all aspects of life. Hormones coordinate reproduction in multicellular organisms, but the mechanisms controlling the collective reproductive investment of social insects are largely unexplored. One important aspect of honey bee (Apis mellifera) reproductive investment consists of raising female-destined larvae into new queens by alloparental care of nurse bees in form of royal jelly provisioning. Artificial selection for commercial royal jelly production over 40years has increased this reproductive investment by an order of magnitude. In a cross-fostering experiment, we establish that this shift in social phenotype is caused by nurse bees. We find no evidence for changes in larval signalling. Instead, the antennae of the nurse bees of the selected stock are more responsive to brood pheromones than control bees. Correspondingly, the selected royal jelly bee nurses are more attracted to brood pheromones than unselected control nurses. Comparative proteomics of the antennae from the selected and unselected stocks indicate putative molecular mechanisms, primarily changes in chemosensation and energy metabolism. We report expression differences of several candidate genes that correlate with the differences in reproductive investment. The functional relevance of these genes is supported by demonstrating that the corresponding proteins can competitively bind one previously described and one newly discovered brood pheromone. Thus, we suggest several chemosensory genes, most prominently OBP16 and CSP4, as candidate mechanisms controlling queen rearing, a key reproductive investment, in honey bees. These findings reveal novel aspects of pheromonal communication in honey bees and explain how sensory changes affect communication and lead to a drastic shift in colony-level resource allocation to sexual reproduction. Thus, pheromonal and hormonal communication may play similar roles for reproductive investment in superorganisms and multicellular organisms, respectively.

Influence of physicochemical factors on environmental availability and distribution of semiochemicals that affect Varroa destructor and phylogenetically close organisms: classification by VHWOC PCA-clustering

Varroa destructor parasites Apis mellifera larvae following the interception of the semiochemicals involved in bee communication; thus, the semiochemical availability and distribution pathways take place within different physicochemical environments. The structure of 172 molecules with semiochemical activity on Varroa destructor was used to compute the representative physicochemical descriptors of the thermodynamic partition among different physicochemical environments: vapor pressure (V), Henry's coefficient (H), water solubility constant (W), octanol-water partition coefficient (O) and organic carbon partition coefficient (C); VHWOC. The principal component analysis (PCA) and hierarchical clustering of VHWOC descriptors allowed us to establish the trend in availability and distribution of the semiochemicals resulting in a 4 classes model of physicochemical environments: Class 1, Soluble/Volatile; Class 2, Soluble; Class 3, Contact; Class 4, Adsorbed/Volatile. Our results suggest that semiochemicals can transit between different thermodynamic equilibrium phases depending on environment conditions. The classification prediction of the model was tested on 6 new molecules obtained from ketonic extracts of L5 Apis mellifera drone larvae; locating them in class 4, which was consistent with their molecular structure. This study can be the starting point for the design of synthetic semiochemicals or for the control of Varroa destructor. In addition, the method can be used in the analysis of other semiochemical groups.

Social modulation of individual differences in dance communication in honey bees

Group-living animals must constantly integrate and respond to information from other individuals within the group. The degree to which consistent inter-individual behavioural differences are influenced by social cues in such groups is largely unanswered. We used the honey bee waggle dance as an experimental paradigm to explore this question. Honey bee foragers use the waggle dance behaviour to communicate information about food sources in the environment to their nest mates. This recruitment process incorporates information about the food reward, the colony food stores and the environmental food availability and plays a major role in ensuring efficient exploitation of the food sources available to the colony. We first observed individual foragers visiting the same food source and quantified the probability and intensity of their dance activity. We found that there are consistent inter-individual differences in both measures of dance activity within a forager group. Next, we removed foragers and observed that this led to a significant increase in the average dance activity of some foragers. The individuals which increased their dance activity were the ones which were more active before the removal. Finally, we allowed recruits to join the foragers at the food source, which had a strong inhibitory effect on the dance activity of all the individual foragers. Our study shows that a complex interplay between individual behavioural differences and social interactions drives the dance communication needed to effectively organise the colony’s collective foraging behaviour. Very little is known about the effect of social cues and signals on consistent inter-individual differences in behaviour amongst workers in the same colony in social insects. We studied this in the recruitment behaviour of honey bee foragers, the dance communication. Foragers visiting the same food source consistently differed in their dance activity, suggesting that there were strong inter-individual differences in the perception of the food reward. We then changed the social cues experienced by the foragers by either removing some of the foragers or allowing recruits to forage at the same food source. We found that the removal of some foragers had an individual specific effect, whereas the presence of all recruits affected all foragers. Our results show that the regulation of foraging in honey bees involves the social modulation of consistent differences in recruitment activity.

Use of high-speed video recording to detect wing beating produced by honey bees

Honey bees use many signals to communicate and coordinate different activities in a colony. In this study, wing and abdomen movements occurring during social interactions between bees were recorded using a high-speed camera. Wing beating was observed in queens, workers and drones. Some of the observed behaviors were reported earlier, but many of them were described here for the first time including drones moving their wings while leaving the nest for mating flights, workers trying to evict them from the nest or in a colony with drone-laying queen, and workers vibrating their wings in contact with a queen outside of the process of swarming, in turns with a shaking signal or while evicting drones from the nest. Queens moved their wings with significantly higher frequency, performing longer pulses of wing beats than drones and workers. Drones vibrated their wings with the frequency similar to workers, but they performed significantly shorter pulses of wing beating. In workers, the frequency of wing beats and the duration of wing-beating pulses were significantly different among various behaviors. Wing beating was performed by bees relatively often in many social contexts and it differed in frequency and pulse duration, which indicates that wing beating may be used for transferring information. High-speed video recording revealed a wide range of new behaviors which may play an important role in honey bee communication. Therefore, it may be used as an alternative or addition to recordings made with microphones and laser vibrometers.

Marked interspecific differences in the neuroanatomy of the male olfactory system of honey bees (genus Apis).

All honey bee species (genus Apis) display a striking mating behavior with the formation of male (drone) congregations, in which virgin queens mate with many drones. Bees' mating behavior relies on olfactory communication involving queen-but also drone pheromones. To explore the evolution of olfactory communication in Apis, we analyzed the neuroanatomical organization of the antennal lobe (primary olfactory center) in the drones of five species from the three main lineages (open-air nesting species: dwarf honey bees Apis florea and giant honey bees Apis dorsata; cavity-nesting species: Apis mellifera, Apis kochevnikovi, and Apis cerana) and from three populations of A. cerana (Borneo, Thailand, and Japan). In addition to differences in the overall number of morphological units, the glomeruli, our data reveal marked differences in the number and position of macroglomeruli, enlarged units putatively dedicated to sex pheromone processing. Dwarf and giant honey bee species possess two macroglomeruli while cavity-nesting bees present three or four macroglomeruli, suggesting an increase in the complexity of sex communication during evolution in the genus Apis. The three A. cerana populations showed differing absolute numbers of glomeruli but the same three macroglomeruli. Overall, we identified six different macroglomeruli in the genus Apis. One of these (called MGb), which is dedicated to the detection of the major queen compound 9-ODA in A. mellifera, was conserved in all species. We discuss the implications of these results for our understanding of sex communication in honey bees and propose a putative scenario of antennal lobe evolution in the Apis genus.

Changes in social behavior are induced by pesticide ingestion in a Neotropical stingless bee

Throughout evolutionary history bees have developed complex communication systems. For social bees, communication is important for both the individual and the development of the colony. Successful communication helps bees to recognize relatives, defend the colony, and promote recruitment to optimize foraging of floral resources. Bees' contribution to pollination is of broad environmental and economic importance. However, studies have reported that anthropogenic actions, such as the use of pesticides, negatively affect bee survival and behavior. We tested the effect of a commercially available pesticide mix containing two pesticide classes, a neonicotinoid and a pyrethroid, on the social behavior of the stingless bee, Melipona quadrifasciata (Lepeletier, 1863). After determining a sublethal dose of the pesticides, we tested the effect of an acute dose on antennation and trophallaxis behaviors of worker bees. Our results showed a drastic reduction in the communication and social interactions of bees.

Sexual dimorphism in visual and olfactory brain centers in the perfume-collecting orchid bee Euglossa dilemma (Hymenoptera, Apidae).

Insect mating behavior is controlled by a diverse array of sex‐specific traits and strategies that evolved to maximize mating success. Orchid bees exhibit a unique suite of perfume‐mediated mating behaviors. Male bees collect volatile compounds from their environment to concoct species‐specific perfume mixtures that are presumably used to attract conspecific females. Despite a growing understanding of the ecology and evolution of chemical signaling in orchid bees, many aspects of the functional adaptations involved, in particular regarding sensory systems, remain unknown. Here we investigated male and female brain morphology in the common orchid bee Euglossa dilemma Bembé & Eltz. Males exhibited increased relative volumes of the Medulla, a visual brain region, which correlated with larger compound eye size (area). While the overall volume of olfactory brain regions was similar between sexes, the antennal lobes exhibited several sex‐specific structures including one male‐specific macroglomerulus. These findings reveal sexual dimorphism in both the visual and the olfactory system of orchid bees. It highlights the tendency of an increased investment in the male visual system similar to that observed in other bee lineages, and suggests that visual input may play a more important role in orchid bee male mating behavior than previously thought. Furthermore, our results suggest that the evolution of perfume communication in orchid bees did not involve drastic changes in olfactory brain morphology compared to other bee lineages.

Static Electricity in the Spatial Orientation and Signaling of Honey Bees

A static electric charge that foraging bees gain by rubbing their body parts against the substrate surface plays a role in social communication of bees. Vibrations of the charged body of a forager with a frequency of approximately 14 Hz indicate the location of the forager bee in a rich variety of bees within a poorly lit nest. The perception of vibrations of the charged ventral body surface of a forager occurs due to the antennal sensory organs of hive mates. An electric charge produced as the foraging bee moves its wings enhances vibrations of the trichoid sensilla, which act as mechanoreceptors. This provides reliable communication between foraging bees and their hive mates.

Combined effects of waggle dance communication and landscape heterogeneity on nectar and pollen uptake in honey bee colonies.

The instructive component of waggle dance communication has been shown to increase resource uptake of Apis mellifera colonies in highly heterogeneous resource environments, but an assessment of its relevance in temperate landscapes with different levels of resource heterogeneity is currently lacking. We hypothesized that the advertisement of resource locations via dance communication would be most relevant in highly heterogeneous landscapes with large spatial variation of floral resources. To test our hypothesis, we placed 24 Apis mellifera colonies with either disrupted or unimpaired instructive component of dance communication in eight Central European agricultural landscapes that differed in heterogeneity and resource availability. We monitored colony weight change and pollen harvest as measure of foraging success. Dance disruption did not significantly alter colony weight change, but decreased pollen harvest compared to the communicating colonies by 40%. There was no general effect of resource availability on nectar or pollen foraging success, but the effect of landscape heterogeneity on nectar uptake was stronger when resource availability was high. In contrast to our hypothesis, the effects of disrupted bee communication on nectar and pollen foraging success were not stronger in landscapes with heterogeneous compared to homogenous resource environments. Our results indicate that in temperate regions intra-colonial communication of resource locations benefits pollen foraging more than nectar foraging, irrespective of landscape heterogeneity. We conclude that the so far largely unexplored role of dance communication in pollen foraging requires further consideration as pollen is a crucial resource for colony development and health.

Ethology: Intrepid translator of the hive

Mark L. Winston reviews a study of Karl von Frisch, the ethologist who unravelled bee communication.

The Role of Vibrations in Population Divergence in the Red Mason Bee, Osmia bicornis

Differences in female preference for certain male characteristics can be a driving force for population divergence and speciation [1-4]. During precopulation, females of the red mason bee, Osmia bicornis, choose suitable males based on, among other criteria, their thoracic vibrations [5]. These vibrations are thought to be a signal of a male's fitness with females choosing the strongest males that can vibrate for the longest time [5]. The precise role of such vibrational signals, however, has not been determined by bioassays, and the vibrations might also play a role in species recognition [6]. There are two main subspecies of O. bicornis in Europe distinguishable only by a single morphological trait [7] (Figure S1). We therefore developed a new bioassay allowing us to impose the vibrations of one live male onto another in order to discern possible selective mate choice by females from O. bicornis originating from different regions of Europe. Females showed strong preference for males from their own region, and male vibrations were the main signal involved in this choice. Thus, vibrational signals encode not only fitness but also information about the region of origin indicating that divergence exists between the different European O. bicornis populations, which might ultimately lead to speciation. These results provide new insights into the scope of vibrational communication in bees, a group previously considered to rely predominantly on chemical signals [8, 9]. Our newly developed method should shed further light on many exciting questions concerning vibrational communication in bees and other animal taxa.