Biology subjects

Leadbeater, E.

Publications and source records attributed to Leadbeater, E..

7 recordsLinked to original sources

bioRxiv2025

Long-term memory formation impacts dietary energy intake but not metabolic rate in honeybees

The brain is energetically expensive. Energy availability may, therefore, determine whether costly cognitive processes such as long-term memory can be expressed. However, there is a limited understanding of the metabolic costs associated with long-term memory formation. Here, we explored the potential induced costs of long-term memory formation using honeybees (Apis mellifera) as a model species. We monitored the sucrose intake of bees over the 20-hour period following a classical spaced olfactory conditioning protocol that induced long-term memory formation, relative to a control group that experienced the same reward schedule but no odour pairing. Bees in the experimental treatment drank significantly more sucrose than controls. We then tested whether the increased energy demands of long-term memory formation showed parallel increases in metabolic rate, by measuring carbon dioxide production in groups of bees at four timepoints following conditioning (1-hour, 4-hours, 24-hours and 72-hours). We found no change in metabolic rate between learning and control groups across all time points. Our results suggest that the cost of long-term memory formation does not translate to increases in metabolic rate, despite an increase in dietary energy intake. Constraints on the expression of cognitive traits may, therefore, be unlikely when energy is unrestricted and can be compensated.

animal behavior and cognition↗

bioRxiv2024

A neural correlate of learning fails to predict foraging efficiency in Bombus terrestris.

The mushroom bodies (MB) are integrative structures in the insect brain that, in social bees, contribute to both visual and olfactory learning. Changes in the density of presynaptic boutons (or microglomeruli) within the calyx region of the MB have been repeatedly linked to various aspects of foraging, including forms of learning that are thought to be key to support foraging efficiency. Here we set out to directly test the relationship between foraging efficiency and microglomerulus density in a bumblebee model, Bombus terrestris. We found no evidence that microglomerulus density predicted real-world foraging performance, nor any relationship with foraging experience. Instead, our data suggest a potential non-linear relationship between individual age, independent of foraging experience, and microglomerulus density in the lip region of the calyx, which is associated with olfactory processing. Our findings suggest that in real-world scenarios there is no simple direct relationship between microglomerular density, learning ability and foraging efficiency in bumblebees, highlighting the gap in knowledge regarding the relationships between learning abilities, neuroanatomy and foraging efficiency.

animal behavior and cognition↗

bioRxiv2022

Honeybees vary collective decision making across landscapes

Honeybee (Apis mellifera) colony foraging decisions arise from the waggle dances of individual foragers, processed and filtered through a series of feedback loops that produce emergent collective behaviour. This process is an example of animal communication at the height of eusociality, yet a growing body of evidence suggests that its value for colony foraging success is heavily dependent on local ecology. Although colonies are thought to vary their use of the waggle dance in response to local ecological conditions, this is yet to be empirically established. Here, we quantify waggle dance use based on colony level dance-decoding and show that the impact of dance use on collective foraging is clear in some colonies but nearly negligible in others. We outline how these estimates of dance use can be combined with land-use data to explore the landscape characteristics that drive collective foraging. Our methodology provides a means to quantify the real-world importance of a celebrated example of animal communication and opens the door to the exploration of the selection pressures that may have driven the evolution of this remarkable collective behaviour.

animal behavior and cognition↗

bioRxiv2021

Ecology dictates the value of memory for foraging bees

"Ecological intelligence" hypotheses posit that animal learning and memory evolves to meet the demands posed by foraging, and together with social intelligence and cognitive buffer hypotheses, provide a key framework for understanding cognitive evolution. However, identifying the critical environments where cognitive investment reaps significant benefits has proved challenging. Here, we capitalise upon seasonal variation in forage availability for a social insect model (Bombus terrestris) to establish how the benefits of short-term memory vary with resource availability. Through analysis of over 1700 foraging trips carried out over two years, we show that short-term memory predicts foraging efficiency - a key determinant of colony fitness - in plentiful spring foraging conditions, but that this relationship is reversed during the summer floral dearth. Our results suggest that selection for enhanced cognitive abilities is unlikely to be limited to harsh environments where food is hard to find or extract, highlighting instead that the complexity of rich and plentiful environments could be a broad driver in the evolution of certain cognitive traits.

animal behavior and cognition↗

bioRxiv2021

Honeybee dance-followers respond similarly to dances regardless of their spatial information content

Honeybees famously use waggle dances to communicate foraging locations to nestmates in the hive, thereby recruiting them to those sites. The decision to dance is governed by rules that, when operating collectively, are assumed to direct foragers to the most profitable locations with little input from potential recruits, who are presumed to respond similarly to any dance regardless of its information content. Yet variation in receiver responses can qualitatively alter collective outcomes. Here, we use network-based diffusion analysis to compare the collective influence of dance information during recruitment to feeders at different distances. We further assess how any such effects might be achieved at the individual level by dance-followers either persisting with known sites when novel targets are distant and/or seeking more accurate spatial information to guide long-distance searches. Contrary to predictions, we found no evidence that dance-followers responses depended on target distance. While dance information was always key to feeder discovery, its importance did not vary with feeder distance, and bees were in fact quicker to abandon previously rewarding sites for distant alternatives. These findings provide empirical support for the longstanding assumption that self-organized foraging by honeybee colonies relies heavily on signal performance rules with limited input from recipients.

animal behavior and cognition↗

bioRxiv2020

Genetic toolkit for sociality predicts castes across the spectrum of social complexity in wasps

Major evolutionary transitions describe how biological complexity arises; e.g. in evolution of complex multicellular bodies, and superorganismal insect societies. Such transitions involve the evolution of division of labour, e.g. as queen and worker castes in insect societies. Castes across different evolutionary lineages are thought to be regulated by a conserved genetic toolkit. However, this hypothesis has not been tested thoroughly across the complexity spectrum of the major transition. Here we reveal, using machine learning analyses of brain transcription, evidence of a shared genetic toolkit across the spectrum of social complexity in Vespid wasps. Whilst molecular processes underpinning the simpler societies (which likely represent the origins of social living) are conserved throughout the major transition, additional processes appear to come into play in more complex societies. Such fundamental shifts in regulatory processes with complexity may typify other major evolutionary transitions, such as the evolution of multicellularity.

evolutionary biology↗

bioRxiv2019

Dancing bees evaluate agricultural forage resources as inferior to central urban land

Recent evidence suggests that flower-rich areas within cities could play an important role in pollinator conservation, but direct comparison of agricultural and urban areas has proved challenging to perform over large scales. Here we use the waggle dances of honeybees (Apis mellifera L.) to evaluate floral resource availability over the entire season at deeply urban or agricultural sites. Through analysis of 3378 dances that were performed over two years by 20 colonies in SE England, we show that foraging trip distance is consistently lower at urban sites across the entire season, implying a higher availability of forage in heavily urbanized areas. Urban bees also collected nectar with a higher mean sugar content. From the self-reported perspective of a generalist pollinator, the modern agricultural landscapes that we studied provided insufficient and transient resources relative to heavily urbanised areas, which may represent important refuges within an impoverished landscape.

ecology↗