Biology subjects

Giray, T.

Publications and source records attributed to Giray, T..

11 recordsLinked to original sources

bioRxiv2026

Caste-specific proboscis extension responses in honey bees to sucrose and royal jelly stimuli

Understanding the nutritional preferences of honey bees (Apis mellifera) is essential for comprehending their behavioral ecology and the division of labor within a colony. While gustatory sensitivity to sucrose is well-documented in workers, a significant research gap exists regarding the sensory responses of queens and their reactions to caste-specific nutrition such as royal jelly. This study utilized the proboscis extension response (PER) assay to compare the food preferences of three distinct bee categories: foragers, 1-day-old workers, and queens. Subjects were presented repeatedly, in a pseudorandom order, with water, sucrose, royal jelly, and a sucrose-royal jelly mixture as gustatory stimuli. Foragers exhibited a high responsiveness to sucrose and showed uniformly low responsiveness to other stimuli. Although 1-day-old workers showed high responsiveness to sucrose, unlike foragers, they also responded to the sucrose-royal jelly mixture. Queens displayed a unique response profile, with near-ceiling responsiveness to both royal jelly and the mixture, followed by response to sucrose solution without habituation. Additionally, responsiveness to the sucrose was higher in foragers than in 1-day-old workers. These findings suggest that the honey bee gustatory and sensory system is tuned to the specific nutritional requirements of caste and age.

animal behavior and cognition↗

bioRxiv2025

Gut microbiota as a modulator of circadian neural development in the honey bee model.

Disruption in gut microbiota during the early postnatal period can disrupt normal neural development and result in long-term behavioral alterations1. Similar to other neural systems, the circadian clock mechanism continues to mature after birth2, yet how microbial disturbances in the early period influence the onset of circadian rhythms and the development of central clock mechanisms remains poorly understood. Here we studied whether early-life gut dysbiosis affects the ontogeny of behavioral circadian rhythms and the maturation of clock neurons using the honey bee (Apis mellifera), a model organism that shares features of postnatal development of behavioral circadian rhythm and clock system3-5 with humans6. Our findings demonstrate that antibiotic-treated and gnotobiotic-reared bees display reduced rhythmicity compared to controls. These treatments also impair the development of the circadian pacemaker, marked by fewer Pigment-Dispersing Factor (PDF)-expressing neurons. Additionally, antibiotic exposure increased the expression of the Insulin-like Growth Factor Binding Protein Acid Labile Subunit (IGFALS) in early ages, which stabilizes the IGF-1/27, a hormone important for neurodevelopmental processes42. Together, these results identify gut microbiota as a modulator of circadian development. Our work provides an understanding of how early-life microbial disruptions influence the development of circadian rhythms, providing information that may extend to other animals, including humans.

neuroscience↗

bioRxiv2025

FlowerPatch: New Method to Measure Nectar Volume in Artificial Flowers

This article proposes a new Flower Patch Nectar Sensor to address the problem of detecting and measuring nectar in artificial flowers used in experiments on pollinator behavior. Traditional methods have focused mainly on recording the visits of pollinators to the flowers, without addressing the dynamic variations in nectar in terms of volume and concentration. The proposed approach provides more detailed information about the nectar consumption by bees and allows determination of the optimal time to refill the flowers. This study introduces an innovative method that uses electrodes and an oscillator circuit to measure the volume of nectar present in the flower. The system correlates the concentration of nectar with a frequency signal that can be processed by a microcontroller. It was evaluated using initial volumes ranging from 1 {micro}L to 4 {micro}L, demonstrating its ability to accurately detect variations in nectar, even up to the point where the frequency approaches zero. The results confirm that this method allows us to identify how the reward offered to pollinators (represented by nectar) varies over time, in terms of concentration, under both controlled and natural conditions. Additionally, graphs are presented that show the relationship between an initial volume of 4 {micro}L and variations in the frequency signal over a period of 25 minutes, highlighting the influence of these factors on nectar dynamics. This work not only introduces an innovative approach for the dynamic monitoring of nectar in artificial flowers, but also lays the groundwork for future studies on the physical and chemical modeling of nectar in response to environmental conditions.

bioengineering↗

bioRxiv2024

Api-TRACE: A System for Honey Bee Tracking in a Constrained Environment to Study Bee Learning Process and the Effect of Lithium on Learning

Learning is an adaptive behavior that improves the performance of bees in foraging, dance communication, predator avoidance, and other tasks. Any deficiencies in learning could be detrimental to the long-term survival of the bee colony. Passive avoidance task is a fundamental procedure for investigating learning. We introduce Api-TRACE, a computer vision-aided system to analyze the avoidance assays. Api-TRACE tracks individual bees from the video footage of the assay and detects the moments when they were exposed to a stimulus. The algorithm provides stimulus exposure duration and learning profiles of each individual bee, enabling fast and detailed analysis of the results. Electric shock avoidance assay is one of the most common experimental methods to assess learning. We designed an apparatus for the electric shock avoidance experiments using within-reach hardware and 3D-printed components. We used Api-TRACE and experimental apparatus to investigate the effect of lithium on bee learning success in passive avoidance and reversal learning paradigms through an electric shock avoidance assay. Lithium is a potential chemical for combating Varroa, a bee (Apis) parasite, and a well-known medication for treating bipolar disorder. It has been known that lithium alters learning in humans and other animals. Before the experiment, we treated the bees with a sucrose solution with 0, 5, 25, and 125 mM LiCl ad libitum. Our results indicated that a decrement in learning performance emerged with increasing lithium doses in the reversal phase but not in the acquisition of the electric shock avoidance assay.

animal behavior and cognition↗

bioRxiv2023

Effects of lithium on locomotor activity and circadian rhythm of honey bees

The miticide effect of lithium on the honey bee (Apis mellifera) parasite Varroa has been discovered. Varroa mite is considered the principal threat to bee health and, as a result, to pollination and food security. In this study, we investigated the behavioral effects of lithium on honey bees, specifically locomotor activity (LMA) level and circadian patterns of LMA, such as rhythmicity, and periodicity. Any effects of lithium on activity may be important for bee health since timing and daylight are critical for bee foraging and bees use of the sun compass for navigation and communication. Both acute and chronic lithium treatments affected the LMA of honey bees. The effect varies depending on light and dark conditions. Chronic treatment with lithium disrupted the rhythmicity and altered the period of the circadian rhythm. While the circadian period was not affected by the light condition in the control group, lithium treatment lengthened the period in constant light condition. Lithium decreased total LMA in a constant light condition where typically activity is increased and not under the dark condition, both in acute and chronic treatments. However, mortality in the high-dose lithium treatment group is higher in the dark environment in the acute experiment. Lithium is also the first-line therapy for bipolar disorder. This disorder causes excessively elevated activity called mania and circadian rhythm abnormalities. The effects of lithium on reducing light-induced activity and the circadian rhythm of bees are reminiscent of its stabilizing effect on activity and circadian rhythms in bipolar disorder treatment.

neuroscience↗

bioRxiv2022

Defensiveness measurement in honey bees (Apis mellifera)and brain expression of associated genes after noxious stimulus

Honey bee (Apis mellifera sp.) colonies and individuals respond variably to disturbances. In this study, we examined the role of neural modulation and metabolism in constitutive and experience-dependent differences in defensive response. We compared brain gene expression in bees of identified gentle and defensive colonies in a standard assay. For neuromodulation, we examined membrane receptor genes for the biogenic amines dopamine (DOPR2), octopamine (OAR), and serotonin (5HT2a), and the enzyme gene in the synthesis pathway (THR). To examine neural metabolism, we assessed the Oxidative Phosphorylation Pathway "OXPHOS" gene expression (i.e., ND51 and ND20-LIKE). Bees of defensive colonies had a significantly lower expression of amine receptor, synthesis genes, and OXPHOS genes. Experience differences or exposure to nociceptive neurons activated by nocive stimuli (electric shock) led to differences in the expression of all genes except 5HT2a. The same target genes demonstrated an increase in expression levels after electric shock and sting response. We discuss the convergence of neuromodulation, neural metabolism

animal behavior and cognition↗

bioRxiv2021

Relationship Between Inter-individual Variation in Circadian Rhythm and Sociality: A case Study Using Halictid Bees

The bee family Halictidae is considered to be an optimal model for the study of social evolution due to its remarkable range of social behaviors. Past studies in circadian rhythms suggest that social species may express more diversity in circadian behaviors than solitary species. However, these previous studies did not make appropriate taxonomic comparisons. To further explore the link between circadian rhythms and sociality, we examine four halictid species with different degrees of sociality, three social species of Lasioglossum, one from Greece and two from Puerto Rico, and a solitary species of Systropha from Greece. Based on our previous observations, we hypothesized that species with greater degree of sociality will show greater inter-individual variation in circadian rhythms than solitary species. We observed distinct differences in their circadian behavior that parallel differences across sociality, where the most social species expressed the highest inter-individual variation. We predict that circadian rhythm differences will be informative of sociality across organisms.

animal behavior and cognition↗

bioRxiv2020

The Role of Temperature on the Development of Circadian Rhythms in Honey Bee Workers

Circadian rhythms in honey bees are involved in various processes that impact colony survival. For example, young nurses take care of the brood constantly throughout the day and lack circadian rhythms, while foragers use the circadian clock to remember and predict food availability in subsequent days. Previous studies suggested that development of circadian rhythms both in the field and the laboratory began around 7-9 days of age. However, not much is understood about the postembryonic development of circadian rhythms in honey bees. In the current study, we examine the effects of socially regulated colony temperature on the ontogeny of circadian rhythms of young workers under controlled laboratory conditions. We hypothesized that temperature plays a key role in the development of circadian rhythmicity in young workers. Our results show that young workers kept at 35{degrees}C develop circadian rhythmicity faster and in greater proportion than bees kept at 25{degrees}C. In addition, we examine if the effect of colony temperature during the first 48 hours after emergence is enough to observe effects on the rate and proportion of development of circadian rhythmicity. We observed that twice as many individuals that were exposed to 35{degrees}C during the first 48 hours develop circadian rhythms compared to individuals kept at 25{degrees}C. In addition, we observed differences in the average endogenous period length consistent with temperature compensation of the circadian rhythms between the 25{degrees}C and 35{degrees}C cohorts. We also observed differences in the degree of period length variation between the 25{degrees}C and 35{degrees}C cohorts, which combined with the proportion of arrhythmic individuals and survival data suggest that development of circadian rhythms is incomplete in individuals exposed to 25{degrees}C adult emergence. This study shows that temperature, which is socially regulated inside the hive, is a key factor that influences the ontogeny of circadian rhythmicity of workers.

animal behavior and cognition↗

bioRxiv2020

The Role of Colony Temperature in the Entrainment of Circadian Rhythms of Honey Bee Foragers

Honey bees utilize their circadian rhythms to accurately predict the time of day. This ability allows foragers to remember the specific timing of food availability and its location for several days. Previous studies have provided strong evidence toward light/dark cycles being the primary Zeitgeber for honey bees. Work in our laboratory described large individual variation in the endogenous period length of honey bee foragers from the same colony and differences in the endogenous rhythms under different constant temperatures. In this study, we further this work by examining temperature inside the honey bee colony. By placing temperature and light data loggers at different locations inside the colony we measured temperature at various locations within the colony. We observed significant oscillations of temperature inside the hive, that show seasonal patterns. We then simulated the observed temperature oscillations in the laboratory and found that using the temperature cycle as a Zeitgeber, foragers present large individual differences in the phase of locomotor rhythms with respect to temperature. Moreover, foragers successfully synchronize their locomotor rhythms to these simulated temperature cycles. Advancing the cycle by six hours, resulted in changes in the phase of activity in some foragers in the assay. The results shown in this study highlight the importance of temperature as a potential Zeitgeber in the field. Future studies will examine the possible functional and evolutionary role of the observed phase differences of circadian rhythms.

animal behavior and cognition↗

bioRxiv2020

Shift work dynamics and division of labor: honeybee foraging and fanning tasks

In complex societies common social needs such as vigilance, care giving, resource gathering, and production are attended around the clock. In humans, these services are constantly provided using a shift work strategy where different individuals, or groups of individuals perform their tasks at different times of the day. However, shift work strategy in job organization in other social organisms remains unclear. Previous studies in honeybees for two jobs support shift work for only pollen foragers and not for nursing behavior. Here we examined shift work dynamics for three types of jobs performed by honeybee foragers. Specifically, we studied pollen foragers, non-pollen foragers and bees fanning at the entrance of the colony, a job important for orientation and temperature control. Major features of the observed shift work were: 1) individuals can be divided into early and late shifts; 2) there are constant workers; 3) based on job, shift work is performed by fewer or greater number of individuals; 4) shift work of an individual is plastic and may change with age; 5) foraging and fanning shifts are coupled yet dissociable. This study adds to the findings that shift work is not exclusive to modern human societies and that a natural form of shift work exists in honeybees. These results suggest that shift work in honeybees is a feature of worker division of labor. Future studies aiming to further understand the structure, function and mechanism of this natural form of shift work in honey bees not only could have an impact on agriculture but also may provide insight into alternative forms of shift work strategies that may reduce the various health problems associated with shift work in humans.

animal behavior and cognition↗

bioRxiv2020

Parallel mechanisms of visual memory formation across distinct regions of the honey bee brain

Visual learning is vital to the behavioral ecology of the Western honey bee (Apis mellifera). Honey bee workers forage for floral resources, a behavior that requires the learning and long-term memory of visual landmarks, but how these memories are mapped to the brain remains poorly understood. To address this gap in our understanding, we collected bees that successfully learned visual associations in a conditioned aversion paradigm and compared gene expression correlates of memory formation in the mushroom bodies, a higher-order sensory integration center classically thought to contribute to learning, as well as the optic lobes, the primary visual neuropil responsible for sensory transduction of visual information. We quantitated expression of CREB and CaMKii, two classical genetic markers of learning and fen-1, a gene specifically associated with punishment learning in vertebrates. As expected, we report substantial involvement of the mushroom bodies for all three markers but additionally demonstrate an unexpected involvement of the optic lobes across a similar time course. Our findings imply the molecular involvement of a sensory neuropil during visual associative learning parallel to a higher-order brain region, furthering our understanding of how a tiny brain processes environmental signals.

animal behavior and cognition↗