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Takeuchi K, Tomioka K. OpsinLW2 serves as a circadian photoreceptor in the entrainment of circadian locomotor rhythm of a firebrat. JOURNAL OF INSECT PHYSIOLOGY 2024; 155:104636. [PMID: 38609008 DOI: 10.1016/j.jinsphys.2024.104636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 04/09/2024] [Accepted: 04/09/2024] [Indexed: 04/14/2024]
Abstract
Photic entrainment is an essential function of the circadian clock, which enables organisms to set the appropriate timing of daily behavioral and physiological events. Recent studies have shown that the mechanisms of the circadian clock and photic entrainment vary among insect species. This study aimed to elucidate the circadian photoreceptors necessary for photic entrainment in firebrats Thermobia domestica, one of the most primitive apterygote insects. A homology search of publicly available RNA sequence (RNA-seq) data from T. domestica exhibited a cryptochrome 2 (cry2) gene and three opsin genes, opsin long wavelength 1 (opLW1), opLW2, and opUV, as candidate circadian photoreceptors. We examined the possible involvement of these genes in photic entrainment of firebrat locomotor rhythms. Firebrats had the highest entrainability to the light-dark cycle of green light. Treatment with dsRNA of the candidate genes strongly downregulated the respective targeted genes, and in the case of opsin genes, other untargeted genes were occasionally downregulated to various degrees. Under constant light, most control firebrats became arrhythmic, whereas a fraction of those treated with double RNAi of the two opLWs remained rhythmic. Behavioral experiments revealed that the transient cycles necessary for re-entrainment to shifted light cycles were lengthened when opLW2 expression was reduced. These results suggest that opLW2 is involved in the photic entrainment of circadian rhythm in firebrats.
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Affiliation(s)
- Kazuki Takeuchi
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Kenji Tomioka
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.
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2
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Abe S, Takahata Y, Miyakawa H. Daphnia uses its circadian clock for short-day recognition in environmental sex determination. Curr Biol 2024; 34:2002-2010.e3. [PMID: 38579713 DOI: 10.1016/j.cub.2024.03.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/12/2024] [Accepted: 03/14/2024] [Indexed: 04/07/2024]
Abstract
Some organisms have developed a mechanism called environmental sex determination (ESD), which allows environmental cues, rather than sex chromosomes or genes, to determine offspring sex.1,2,3,4 ESD is advantageous to optimize sex ratios according to environmental conditions, enhancing reproductive success.5,6 However, the process by which organisms perceive and translate diverse environmental signals into offspring sex remains unclear. Here, we analyzed the environmental perception mechanism in the crustacean, Daphnia pulex, a seasonal (photoperiodic) ESD arthropod, capable of producing females under long days and males under short days.7,8,9,10 Through breeding experiments, we found that their circadian clock likely contributes to perception of day length. To explore this further, we created a genetically modified daphnid by knocking out the clock gene, period, using genome editing. Knockout disrupted the daphnid's ability to sustain diel vertical migration (DVM) under constant darkness, driven by the circadian clock, and leading them to produce females regardless of day length. Additionally, when exposed to an analog of juvenile hormone (JH), an endocrine factor synthesized in mothers during male production, or subjected to unfavorable conditions of high density and low food availability, these knockout daphnids produced males regardless of day length, like wild-type daphnids. Based on these findings, we propose that recognizing short days via the circadian clock is the initial step in sex determination. This recognition subsequently triggers male production by signaling the endocrine system, specifically via the JH signal. Establishment of a connection between these two processes may be the crucial element in evolution of ESD in Daphnia.
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Affiliation(s)
- Shione Abe
- Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan
| | - Yugo Takahata
- Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan
| | - Hitoshi Miyakawa
- Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan.
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3
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Giannoni-Guzmán MA, Perez Claudio E, Aleman-Rios J, Diaz Hernandez G, Perez Torres M, Melendez Moreno A, Loubriel D, Moore D, Giray T, Agosto-Rivera JL. The role of temperature on the development of circadian rhythms in honey bee workers. PeerJ 2024; 12:e17086. [PMID: 38500530 PMCID: PMC10946391 DOI: 10.7717/peerj.17086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 02/20/2024] [Indexed: 03/20/2024] Open
Abstract
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. At the same time, foragers use the circadian clock to remember and predict food availability in subsequent days. Previous studies exploring the ontogeny of circadian rhythms of workers showed that the onset of rhythms is faster in the colony environment (~2 days) than if workers were immediately isolated after eclosion (7-9 days). However, which specific environmental factors influenced the early development of worker circadian rhythms remained unknown. We hypothesized that brood nest temperature plays a key role in the development of circadian rhythmicity in young workers. Our results show that young workers kept at brood nest-like temperatures (33-35 °C) in the laboratory develop circadian rhythms faster and in greater proportion than bees kept at lower temperatures (24-26 °C). In addition, we examined if the effect of colony temperature during the first 48 h after emergence is sufficient to increase the rate and proportion of development of circadian rhythmicity. We observed that twice as many individuals exposed to 35 °C during the first 48 h developed circadian rhythms compared to individuals kept at 25 °C, suggesting a critical developmental period where brood nest temperatures are important for the development of the circadian system. Together, our findings show that temperature, which is socially regulated inside the hive, is a key factor that influences the ontogeny of circadian rhythmicity of workers.
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Affiliation(s)
| | - Eddie Perez Claudio
- Department of Biomedical Informatics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Janpierre Aleman-Rios
- Department of Biology, University of Puerto Rico Rio Piedras, San Juan, Puerto Rico, United States
| | - Gabriel Diaz Hernandez
- Department of Biology, University of Puerto Rico Rio Piedras, San Juan, Puerto Rico, United States
| | - Melina Perez Torres
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States
| | | | - Darimar Loubriel
- Department of Biology, University of Puerto Rico Rio Piedras, San Juan, Puerto Rico, United States
| | - Darrell Moore
- Department of Biological Sciences, East Tennessee State University, Johnson City, Tennessee, United States
| | - Tugrul Giray
- Department of Biology, University of Puerto Rico Rio Piedras, San Juan, Puerto Rico, United States
| | - Jose L. Agosto-Rivera
- Department of Biology, University of Puerto Rico Rio Piedras, San Juan, Puerto Rico, United States
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4
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Beer K, Zupanc GKH, Helfrich-Förster C. Ingeborg Beling and the time memory in honeybees: almost one hundred years of research. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2024; 210:189-201. [PMID: 38472409 PMCID: PMC10995049 DOI: 10.1007/s00359-024-01691-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/17/2024] [Accepted: 01/25/2024] [Indexed: 03/14/2024]
Abstract
Bees are known for their ability to forage with high efficiency. One of their strategies to avoid unproductive foraging is to be at the food source at the right time of the day. Approximately one hundred years ago, researchers discovered that honeybees have a remarkable time memory, which they use for optimizing foraging. Ingeborg Beling was the first to examine this time memory experimentally. In her doctoral thesis, completed under the mentorship of Karl von Frisch in 1929, she systematically examined the capability of honeybees to remember specific times of the day at which they had been trained to appear at a feeding station. Beling was a pioneer in chronobiology, as she described the basic characteristics of the circadian clock on which the honeybee's time memory is based. Unfortunately, after a few years of extremely productive research, she ended her scientific career, probably due to family reasons or political pressure to reduce the number of women in the workforce. Here, we present a biographical sketch of Ingeborg Beling and review her research on the time memory of honeybees. Furthermore, we discuss the significance of her work, considering what is known about time memory today - nearly 100 years after she conducted her experiments.
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Affiliation(s)
- Katharina Beer
- Behavioral Physiology and Sociobiology, Biocentre, University of Würzburg, Würzburg, Germany
| | - Günther K H Zupanc
- Laboratory of Neurobiology, Department of Biology, Northeastern University, Boston, MA, 02115, USA.
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5
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Shpigler HY, Yaniv A, Gernat T, Robinson GE, Bloch G. The Influences of Illumination Regime on Egg-laying Rhythms of Honey Bee Queens. J Biol Rhythms 2022; 37:609-619. [PMID: 36226630 PMCID: PMC9727117 DOI: 10.1177/07487304221126782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Honey bee queens show extreme fecundity, commonly laying more than a thousand eggs in a single day. It has proven challenging to study the temporal organization of egg-laying behavior because queens are typically active around the clock in the dark cavity of a densely populated nest. To contend with this challenge, we developed two novel methods allowing detailed monitoring of queen activity and egg laying. We first adapted a high-resolution, continuous, tracking system allowing to track the position of barcode-tagged queens in observation hives with colonies foraging outside. We found that the queen is active ~96% of the day with typically no diurnal rhythm. Next, we developed a new laboratory procedure to monitor egg laying at single egg resolution under different light regimes. We found that under constant darkness (DD) and temperature conditions, queens laid eggs with no circadian rhythms. Queen fecundity was severely reduced under constant light (LL). Under a 12:12 illumination regime, queen fecundity was comparable to under constant darkness, with a higher number of eggs during the light phase. These daily rhythms in egg laying continued when these queens were released to DD conditions, suggesting that egg-laying rhythms are influenced by endogenous circadian clocks. These results suggest that honey bee queens are active and lay eggs around the clock with no diurnal rhythms. Light has complex influences on these behaviors, but more studies are needed to determine whether these effects reflect the influence of light directly on the queen or indirectly by affecting workers that interact with the queen.
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Affiliation(s)
- Hagai Y. Shpigler
- Department of Ecology, Evolution, and
Behavior, The Alexander Silberman Institute of Life Sciences, The Hebrew University
of Jerusalem, Jerusalem, Israel,Carl R. Woese Institute for Genomic
Biology, University of Illinois Urbana–Champaign, Urbana, Illinois, USA,Department of Entomology, Agricultural
Research Organization, The Volcani Center, Rishon LeZion, Israel,Hagai Y. Shpigler,
Department of Entomology, Agricultural Research Organization, The Volcani
Center, Rishon LeZion, Israel; e-mail:
| | - Almog Yaniv
- Department of Ecology, Evolution, and
Behavior, The Alexander Silberman Institute of Life Sciences, The Hebrew University
of Jerusalem, Jerusalem, Israel
| | - Tim Gernat
- Carl R. Woese Institute for Genomic
Biology, University of Illinois Urbana–Champaign, Urbana, Illinois, USA
| | - Gene E. Robinson
- Carl R. Woese Institute for Genomic
Biology, University of Illinois Urbana–Champaign, Urbana, Illinois, USA,Entomology Department, University of
Illinois Urbana–Champaign, Urbana, Illinois, USA,Neuroscience Program, University of
Illinois Urbana–Champaign, Urbana, Illinois, USA
| | - Guy Bloch
- Department of Ecology, Evolution, and
Behavior, The Alexander Silberman Institute of Life Sciences, The Hebrew University
of Jerusalem, Jerusalem, Israel,Guy Bloch, Department of
Ecology, Evolution, and Behavior, The Alexander Silberman Institute of Life
Sciences, The Hebrew University of Jerusalem, Berman 114, Jerusalem 9190401,
Israel; e-mail:
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6
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Hamanaka Y, Lu Z, Shiga S. Morphology and synaptic connections of pigment-dispersing factor-immunoreactive neurons projecting to the lateral protocerebrum in the large black chafer, Holotrichia parallela. J Comp Neurol 2022; 530:2994-3010. [PMID: 35881849 DOI: 10.1002/cne.25391] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/30/2022] [Accepted: 07/01/2022] [Indexed: 11/08/2022]
Abstract
Pigment-dispersing factor (PDF) is a well-known output neuropeptide modulator of circadian pacemakers in insects. Here, we investigated PDF-immunoreactive (ir) neurons in the brain of the large black chafer Holotrichia parallela to search for circadian neural components, which are potentially involved in its circabidian rhythm. PDF-ir cells were exclusively detected near the accessory medulla (AME) as a cluster of ∼ 100 cells with almost homogeneous size. No other cells exhibited immunoreactivity. The PDF-ir cells send beaded fibers into the proximal half of the AME and ventral elongation in an anterior region between the medulla (ME) and lobula (LO). Neither the lamina, ME, LO, nor lobula plate receives PDF-ir fibers. Primary axons derived from the PDF-ir cells extend toward the contralateral hemisphere through the dorsolateral protocerebrum anterior to the calyx to connect the bilateral AME. The axons form varicose outgrowths exclusively in the lateral protocerebrum. Double labeling with antisynapsin revealed partial overlaps between PDF-ir varicosities and synapsin-ir puncta. Thus, it was assumed that the PDF-ir fibers form output synapses there. To verify this, we investigated the ultrastructure of the PDF-ir varicosities in the lateral protocerebrum by preembedding immunoelectron microscopy. The PDF-ir profiles contain small clear synaptic vesicles as well as both PDF-positive and PDF-negative dense-core vesicles, and the profiles form output synapses upon unknown profiles and receive synapses from other PDF-ir profiles. PDF neurons near the AME are considered to be prominent circadian pacemakers in the cockroach and flies. Their possible function in the circabidian rhythm was discussed based on these anatomical insights.
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Affiliation(s)
- Yoshitaka Hamanaka
- Laboratory of Comparative Neurobiology, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
| | - Zhiyuan Lu
- Department of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, Canada
| | - Sakiko Shiga
- Laboratory of Comparative Neurobiology, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
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7
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Lee IH, Duvall LB. Maternally Instigated Diapause in Aedes albopictus: Coordinating Experience and Internal State for Survival in Variable Environments. Front Behav Neurosci 2022; 16:778264. [PMID: 35548691 PMCID: PMC9082357 DOI: 10.3389/fnbeh.2022.778264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 03/15/2022] [Indexed: 11/13/2022] Open
Abstract
The Asian tiger mosquito, Aedes albopictus, is one of the most dangerous invasive species in the world. Females bite mammalian hosts, including humans, to obtain blood for egg development. The ancestral range of Ae. albopictus likely spanned from India to Japan and this species has since invaded a substantial portion of the globe. Ae. albopictus can be broadly categorized into temperate and tropical populations. One key to their ability to invade diverse ecological spaces is the capacity of females to detect seasonal changes and produce stress-resistant eggs that survive harsh winters. Females living in temperate regions respond to cues that predict the onset of unfavorable environmental conditions by producing eggs that enter maternally instigated embryonic diapause, a developmentally arrested state, which allows species survival by protecting the embryos until favorable conditions return. To appropriately produce diapause eggs, the female must integrate environmental cues and internal physiological state (blood feeding and reproductive status) to allocate nutrients and regulate reproduction. There is variation in reproductive responses to environmental cues between interfertile tropical and temperate populations depending on whether females are actively producing diapause vs. non-diapause eggs and whether they originate from populations that are capable of diapause. Although diapause-inducing environmental cues and diapause eggs have been extensively characterized, little is known about how the female detects gradual environmental changes and coordinates her reproductive status with seasonal dynamics to lay diapause eggs in order to maximize offspring survival. Previous studies suggest that the circadian system is involved in detecting daylength as a critical cue. However, it is unknown which clock network components are important, how these connect to reproductive physiology, and how they may differ between behavioral states or across populations with variable diapause competence. In this review, we showcase Ae. albopictus as an emerging species for neurogenetics to study how the nervous system combines environmental conditions and internal state to optimize reproductive behavior. We review environmental cues for diapause induction, downstream pathways that control female metabolic changes and reproductive capacity, as well as diapause heterogeneity between populations with different evolutionary histories. We highlight genetic tools that can be implemented in Ae. albopictus to identify signaling molecules and cellular circuits that control diapause. The tools and discoveries made in this species could translate to a broader understanding of how environmental cues are interpreted to alter reproductive physiology in other species and how populations with similar genetic and circuit organizations diversify behavioral patterns. These approaches may yield new targets to interfere with mosquito reproductive capacity, which could be exploited to reduce mosquito populations and the burden of the pathogens they transmit.
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Affiliation(s)
| | - Laura B. Duvall
- Department of Biological Sciences, Columbia University in the City of New York, New York, NY, United States
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8
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Das B, de Bekker C. Time-course RNASeq of Camponotus floridanus forager and nurse ant brains indicate links between plasticity in the biological clock and behavioral division of labor. BMC Genomics 2022; 23:57. [PMID: 35033027 PMCID: PMC8760764 DOI: 10.1186/s12864-021-08282-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 12/24/2021] [Indexed: 12/19/2022] Open
Abstract
Background Circadian clocks allow organisms to anticipate daily fluctuations in their environment by driving rhythms in physiology and behavior. Inter-organismal differences in daily rhythms, called chronotypes, exist and can shift with age. In ants, age, caste-related behavior and chronotype appear to be linked. Brood-tending nurse ants are usually younger individuals and show “around-the-clock” activity. With age or in the absence of brood, nurses transition into foraging ants that show daily rhythms in activity. Ants can adaptively shift between these behavioral castes and caste-associated chronotypes depending on social context. We investigated how changes in daily gene expression could be contributing to such behavioral plasticity in Camponotus floridanus carpenter ants by combining time-course behavioral assays and RNA-Sequencing of forager and nurse brains. Results We found that nurse brains have three times fewer 24 h oscillating genes than foragers. However, several hundred genes that oscillated every 24 h in forager brains showed robust 8 h oscillations in nurses, including the core clock genes Period and Shaggy. These differentially rhythmic genes consisted of several components of the circadian entrainment and output pathway, including genes said to be involved in regulating insect locomotory behavior. We also found that Vitellogenin, known to regulate division of labor in social insects, showed robust 24 h oscillations in nurse brains but not in foragers. Finally, we found significant overlap between genes differentially expressed between the two ant castes and genes that show ultradian rhythms in daily expression. Conclusion This study provides a first look at the chronobiological differences in gene expression between forager and nurse ant brains. This endeavor allowed us to identify a putative molecular mechanism underlying plastic timekeeping: several components of the ant circadian clock and its output can seemingly oscillate at different harmonics of the circadian rhythm. We propose that such chronobiological plasticity has evolved to allow for distinct regulatory networks that underlie behavioral castes, while supporting swift caste transitions in response to colony demands. Behavioral division of labor is common among social insects. The links between chronobiological and behavioral plasticity that we found in C. floridanus, thus, likely represent a more general phenomenon that warrants further investigation. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-08282-x.
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Affiliation(s)
- Biplabendu Das
- Department of Biology, College of Sciences, University of Central Florida, Orlando, FL, 32816, USA. .,Genomics and Bioinformatics Cluster, University of Central Florida, Orlando, FL, 32816, USA.
| | - Charissa de Bekker
- Department of Biology, College of Sciences, University of Central Florida, Orlando, FL, 32816, USA. .,Genomics and Bioinformatics Cluster, University of Central Florida, Orlando, FL, 32816, USA.
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9
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Siehler O, Wang S, Bloch G. Remarkable Sensitivity of Young Honey Bee Workers to Multiple Non-photic, Non-thermal, Forager Cues That Synchronize Their Daily Activity Rhythms. Front Physiol 2022; 12:789773. [PMID: 35002771 PMCID: PMC8733668 DOI: 10.3389/fphys.2021.789773] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 11/18/2021] [Indexed: 11/30/2022] Open
Abstract
Honey bees live in colonies containing tens of thousands of workers that coordinate their activities to produce efficient colony-level behavior. In free-foraging colonies, nest bees are entrained to the forager daily phase of activity even when experiencing conflicting light-dark illumination regime, but little is known on the cues mediating this potent social synchronization. We monitored locomotor activity in an array of individually caged bees in which we manipulated the contact with neighbour bees. We used circular statistics and coupling function analyses to estimate the degree of social synchronization. We found that young bees in cages connected to cages housing foragers showed stronger rhythms, better synchronization with each other, higher coupling strength, and a phase more similar to that of the foragers compared to similar bees in unconnected cages. These findings suggest that close distance contacts are sufficient for social synchronization or that cage connection facilitated the propagation of time-giving social cues. Coupling strength was higher for bees placed on the same tray compared with bees at a similar distance but on a different tray, consistent with the hypothesis that substrate borne vibrations mediate phase synchronization. Additional manipulation of the contact between cages showed that social synchronization is better among bees in cages connected with tube with a single mesh partition compared to sealed tubes consistent with the notion that volatile cues act additively to substrate borne vibrations. These findings are consistent with self-organization models for social synchronization of activity rhythms and suggest that the circadian system of honey bees evolved remarkable sensitivity to non-photic, non-thermal, time giving entraining cues enabling them to tightly coordinate their behavior in the dark and constant physical environment of their nests.
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Affiliation(s)
- Oliver Siehler
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Shuo Wang
- Department of Mechanical and Aerospace Engineering, The University of Texas at Arlington, Arlington, TX, United States
| | - Guy Bloch
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.,The Federmann Center for the Study of Rationality, The Hebrew University of Jerusalem, Jerusalem, Israel
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10
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Beer K, Härtel S, Helfrich-Förster C. The pigment-dispersing factor neuronal network systematically grows in developing honey bees. J Comp Neurol 2021; 530:1321-1340. [PMID: 34802154 DOI: 10.1002/cne.25278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 10/25/2021] [Accepted: 11/11/2021] [Indexed: 11/08/2022]
Abstract
The neuropeptide pigment-dispersing factor (PDF) plays a prominent role in the circadian clock of many insects including honey bees. In the honey bee brain, PDF is expressed in about 15 clock neurons per hemisphere that lie between the central brain and the optic lobes. As in other insects, the bee PDF neurons form wide arborizations in the brain, but certain differences are evident. For example, they arborize only sparsely in the accessory medulla (AME), which serves as important communication center of the circadian clock in cockroaches and flies. Furthermore, all bee PDF neurons cluster together, which makes it impossible to distinguish individual projections. Here, we investigated the developing bee PDF network and found that the first three PDF neurons arise in the third larval instar and form a dense network of varicose fibers at the base of the developing medulla that strongly resembles the AME of hemimetabolous insects. In addition, they send faint fibers toward the lateral superior protocerebrum. In last larval instar, PDF cells with larger somata appear and send fibers toward the distal medulla and the medial protocerebrum. In the dorsal part of the medulla serpentine layer, a small PDF knot evolves from which PDF fibers extend ventrally. This knot disappears during metamorphosis and the varicose arborizations in the putative AME become fainter. Instead, a new strongly stained PDF fiber hub appears in front of the lobula. Simultaneously, the number of PDF neurons increases and the PDF neuronal network in the brain gets continuously more complex.
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Affiliation(s)
- Katharina Beer
- Department of Neurobiology and Genetics, Biocenter, University of Würzburg, Würzburg, Germany
| | - Stephan Härtel
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Würzburg, Germany
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11
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Giannoni-Guzmán MA, Rivera-Rodriguez EJ, Aleman-Rios J, Melendez Moreno AM, Pérez Ramos M, Pérez-Claudio E, Loubriel D, Moore D, Giray T, Agosto-Rivera JL. The Role of Colony Temperature in the Entrainment of Circadian Rhythms of Honey Bee Foragers. ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA 2021; 114:596-605. [PMID: 34512858 PMCID: PMC8423108 DOI: 10.1093/aesa/saab021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Indexed: 06/13/2023]
Abstract
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 the 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 the 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 for temperature. Moreover, foragers successfully synchronize their locomotor rhythms to these simulated temperature cycles. Advancing the cycle by six hours, resulting in changes in the phase of activity in some foragers in the assay. The results are 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.
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Affiliation(s)
| | | | - Janpierre Aleman-Rios
- Department of Biology, University of Puerto Rico Rio Piedras Campus, San Juan, PR, USA
| | | | | | - Eddie Pérez-Claudio
- Department of Biomedical Informatics, University of Pittsburgh, School of Medicine, Pittsburgh, PA, USA
| | - Darimar Loubriel
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Darrell Moore
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN, USA
| | - Tugrul Giray
- Department of Biology, University of Puerto Rico Rio Piedras Campus, San Juan, PR, USA
| | - Jose L Agosto-Rivera
- Department of Biology, University of Puerto Rico Rio Piedras Campus, San Juan, PR, USA
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12
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Colizzi FS, Beer K, Cuti P, Deppisch P, Martínez Torres D, Yoshii T, Helfrich-Förster C. Antibodies Against the Clock Proteins Period and Cryptochrome Reveal the Neuronal Organization of the Circadian Clock in the Pea Aphid. Front Physiol 2021; 12:705048. [PMID: 34366893 PMCID: PMC8336691 DOI: 10.3389/fphys.2021.705048] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 06/07/2021] [Indexed: 12/20/2022] Open
Abstract
Circadian clocks prepare the organism to cyclic environmental changes in light, temperature, or food availability. Here, we characterized the master clock in the brain of a strongly photoperiodic insect, the aphid Acyrthosiphon pisum, immunohistochemically with antibodies against A. pisum Period (PER), Drosophila melanogaster Cryptochrome (CRY1), and crab Pigment-Dispersing Hormone (PDH). The latter antibody detects all so far known PDHs and PDFs (Pigment-Dispersing Factors), which play a dominant role in the circadian system of many arthropods. We found that, under long days, PER and CRY are expressed in a rhythmic manner in three regions of the brain: the dorsal and lateral protocerebrum and the lamina. No staining was detected with anti-PDH, suggesting that aphids lack PDF. All the CRY1-positive cells co-expressed PER and showed daily PER/CRY1 oscillations of high amplitude, while the PER oscillations of the CRY1-negative PER neurons were of considerable lower amplitude. The CRY1 oscillations were highly synchronous in all neurons, suggesting that aphid CRY1, similarly to Drosophila CRY1, is light sensitive and its oscillations are synchronized by light-dark cycles. Nevertheless, in contrast to Drosophila CRY1, aphid CRY1 was not degraded by light, but steadily increased during the day and decreased during the night. PER was always located in the nuclei of the clock neurons, while CRY was predominantly cytoplasmic and revealed the projections of the PER/CRY1-positive neurons. We traced the PER/CRY1-positive neurons through the aphid protocerebrum discovering striking similarities with the circadian clock of D. melanogaster: The CRY1 fibers innervate the dorsal and lateral protocerebrum and putatively connect the different PER-positive neurons with each other. They also run toward the pars intercerebralis, which controls hormone release via the neurohemal organ, the corpora cardiaca. In contrast to Drosophila, the CRY1-positive fibers additionally travel directly toward the corpora cardiaca and the close-by endocrine gland, corpora allata. This suggests a direct link between the circadian clock and the photoperiodic control of hormone release that can be studied in the future.
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Affiliation(s)
- Francesca Sara Colizzi
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Katharina Beer
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Paolo Cuti
- Institute for Integrative Systems Biology (I2SysBio), University of Valencia and CSIC, Valencia, Spain
| | - Peter Deppisch
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - David Martínez Torres
- Institute for Integrative Systems Biology (I2SysBio), University of Valencia and CSIC, Valencia, Spain
| | - Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Charlotte Helfrich-Förster
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
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13
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Mapping PERIOD-immunoreactive cells with neurons relevant to photoperiodic response in the bean bug Riptortus pedestris. Cell Tissue Res 2021; 385:571-583. [PMID: 33954831 DOI: 10.1007/s00441-021-03451-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/15/2021] [Indexed: 12/23/2022]
Abstract
Circadian clock genes are involved in photoperiodic responses in many insects; however, there is a lack of understanding in the neural pathways that process photoperiodic information involving circadian clock cells. PERIOD-immunohistochemistry was conducted in the bean bug Riptortus pedestris to localise clock cells and their anatomical relationship with other brain neurons necessary for the photoperiodic response. PERIOD-immunoreactive cells were found in the six brain regions. In the optic lobe, two cell groups called lateral neuron lateral (LNl) and lateral neuron medial (LNm), were labelled anterior medial to the medulla and lobula, respectively. In the protocerebrum of the central brain, dorsal neuron (Prd), posterior neuron (Prp), and antennal lobe posterior neuron (pAL) were found. In the deutocerebrum, antennal lobe local neurons (ALln) were detected. Double immunohistochemistry revealed that PERIOD and serotonin were not co-localised. Furthermore, pigment-dispersing factor-immunoreactive neurons and anterior lobula neurons essential for R. pedestris photoperiodic response were not PERIOD immunopositive. LNl cells were located in the vicinity of the pigment-dispersing factor immunoreactive cells at the anterior base of the medulla. LNm cells were located close to the somata of the anterior lobula neurons. Fibres from the anterior lobula neurons and pigment-dispersing factor-immunoreactive neurons had contacts at the anterior base of the medulla. It is suggested that LNl cells work as clock cells involved in the photoperiodic response and the region at the medulla anterior base serves as a hub to receive photic and clock information relevant to the photoperiodic clock in R. pedestris.
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14
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Miler K, Opalek M, Ostap‐Chec M, Stec D. Diel rhythmicity of alcohol‐induced intoxication in the honeybee workers. J Zool (1987) 2021. [DOI: 10.1111/jzo.12872] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- K. Miler
- Institute of Systematics and Evolution of Animals Polish Academy of Sciences Kraków Poland
| | - M. Opalek
- Institute of Environmental Sciences Faculty of Biology Jagiellonian University Kraków Poland
| | - M. Ostap‐Chec
- Institute of Environmental Sciences Faculty of Biology Jagiellonian University Kraków Poland
| | - D. Stec
- Institute of Zoology and Biomedical Research Faculty of Biology Jagiellonian University Kraków Poland
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15
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Beer K, Helfrich-Förster C. Post-embryonic Development of the Circadian Clock Seems to Correlate With Social Life Style in Bees. Front Cell Dev Biol 2020; 8:581323. [PMID: 33282863 PMCID: PMC7689364 DOI: 10.3389/fcell.2020.581323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 10/21/2020] [Indexed: 11/13/2022] Open
Abstract
Social life style can influence many aspects of an animal’s daily life, but it has not yet been clarified, whether development of the circadian clock in social and solitary living bees differs. In a comparative study, with the social honey bee, Apis mellifera, and the solitary mason bee, Osmia bicornis, we now found indications for a differentially timed clock development in social and solitary bees. Newly emerged solitary bees showed rhythmic locomotion right away and the number of neurons in the brain that produce the clock component pigment-dispersing factor (PDF) did not change during aging of the adult solitary bee. Honey bees on the other hand, showed no circadian locomotion directly after emergence and the neuronal clock network continued to grow after emergence. Social bees appear to emerge at an early developmental stage at which the circadian clock is still immature, but bees are already able to fulfill in-hive tasks.
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Affiliation(s)
- Katharina Beer
- Department of Neurobiology and Genetics, Biocenter, University of Würzburg, Würzburg, Germany
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16
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Beer K, Helfrich-Förster C. Model and Non-model Insects in Chronobiology. Front Behav Neurosci 2020; 14:601676. [PMID: 33328925 PMCID: PMC7732648 DOI: 10.3389/fnbeh.2020.601676] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 10/30/2020] [Indexed: 12/20/2022] Open
Abstract
The fruit fly Drosophila melanogaster is an established model organism in chronobiology, because genetic manipulation and breeding in the laboratory are easy. The circadian clock neuroanatomy in D. melanogaster is one of the best-known clock networks in insects and basic circadian behavior has been characterized in detail in this insect. Another model in chronobiology is the honey bee Apis mellifera, of which diurnal foraging behavior has been described already in the early twentieth century. A. mellifera hallmarks the research on the interplay between the clock and sociality and complex behaviors like sun compass navigation and time-place-learning. Nevertheless, there are aspects of clock structure and function, like for example the role of the clock in photoperiodism and diapause, which can be only insufficiently investigated in these two models. Unlike high-latitude flies such as Chymomyza costata or D. ezoana, cosmopolitan D. melanogaster flies do not display a photoperiodic diapause. Similarly, A. mellifera bees do not go into "real" diapause, but most solitary bee species exhibit an obligatory diapause. Furthermore, sociality evolved in different Hymenoptera independently, wherefore it might be misleading to study the social clock only in one social insect. Consequently, additional research on non-model insects is required to understand the circadian clock in Diptera and Hymenoptera. In this review, we introduce the two chronobiology model insects D. melanogaster and A. mellifera, compare them with other insects and show their advantages and limitations as general models for insect circadian clocks.
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Affiliation(s)
- Katharina Beer
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocentre, Am Hubland, University of Würzburg, Würzburg, Germany
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17
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Tackenberg MC, Giannoni-Guzmán MA, Sanchez-Perez E, Doll CA, Agosto-Rivera JL, Broadie K, Moore D, McMahon DG. Neonicotinoids disrupt circadian rhythms and sleep in honey bees. Sci Rep 2020; 10:17929. [PMID: 33087835 PMCID: PMC7578099 DOI: 10.1038/s41598-020-72041-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 07/02/2020] [Indexed: 12/14/2022] Open
Abstract
Honey bees are critical pollinators in ecosystems and agriculture, but their numbers have significantly declined. Declines in pollinator populations are thought to be due to multiple factors including habitat loss, climate change, increased vulnerability to disease and parasites, and pesticide use. Neonicotinoid pesticides are agonists of insect nicotinic cholinergic receptors, and sub-lethal exposures are linked to reduced honey bee hive survival. Honey bees are highly dependent on circadian clocks to regulate critical behaviors, such as foraging orientation and navigation, time-memory for food sources, sleep, and learning/memory processes. Because circadian clock neurons in insects receive light input through cholinergic signaling we tested for effects of neonicotinoids on honey bee circadian rhythms and sleep. Neonicotinoid ingestion by feeding over several days results in neonicotinoid accumulation in the bee brain, disrupts circadian rhythmicity in many individual bees, shifts the timing of behavioral circadian rhythms in bees that remain rhythmic, and impairs sleep. Neonicotinoids and light input act synergistically to disrupt bee circadian behavior, and neonicotinoids directly stimulate wake-promoting clock neurons in the fruit fly brain. Neonicotinoids disrupt honey bee circadian rhythms and sleep, likely by aberrant stimulation of clock neurons, to potentially impair honey bee navigation, time-memory, and social communication.
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Affiliation(s)
| | | | - Erik Sanchez-Perez
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Caleb A Doll
- Department of Pediatrics, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, 8004, USA
| | - José L Agosto-Rivera
- Department of Biology, University of Puerto Rico - Río Piedras, San Juan, PR, USA
| | - Kendal Broadie
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Darrell Moore
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN, USA
| | - Douglas G McMahon
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA.
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
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18
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Siehler O, Bloch G. Colony Volatiles and Substrate-borne Vibrations Entrain Circadian Rhythms and Are Potential Cues Mediating Social Synchronization in Honey Bee Colonies. J Biol Rhythms 2020; 35:246-256. [PMID: 32295458 DOI: 10.1177/0748730420913362] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Internal circadian clocks organize animal behavior and physiology and are entrained by ecologically relevant external time-givers such as light and temperature cycles. In the highly social honey bee, social time-givers are potent and can override photic entrainment, but the cues mediating social entrainment are unknown. Here, we tested whether substrate-borne vibrations and hive volatiles can mediate social synchronization in honey bees. We first placed newly emerged worker bees on the same or on a different substrate on which we placed cages with foragers entrained to ambient day-night cycles, while minimizing the spread of volatiles between cages. In the second experiment, we exposed young bees to constant airflow drawn from either a free-foraging colony or a similar-size control hive containing only heated empty honeycombs, while minimizing transfer of substrate-borne vibrations between cages. After 6 days, we isolated each focal bee in an individual cage in an environmental chamber and monitored her locomotor activity. We repeated each experiment 5 times, each trial with bees from a different source colony, monitoring a total of more than 1000 bees representing diverse genotypes. We found that bees placed on the same substrate as foragers showed a stronger phase coherence and a phase more similar to that of foragers compared with bees placed on a different substrate. In the second experiment, bees exposed to air drawn from a colony showed a stronger phase coherence and a phase more similar to that of foragers compared with bees exposed to air from an empty hive. These findings lend credence to the hypothesis that surrogates of activity entrain circadian rhythms and suggest that multiple social cues can act in concert to entrain social insect colonies to a common phase.
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Affiliation(s)
- Oliver Siehler
- Department of Ecology, Evolution and Behavior, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat-Ram, Jerusalem, Israel
| | - Guy Bloch
- Department of Ecology, Evolution and Behavior, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat-Ram, Jerusalem, Israel.,The Federmann Center for the Study of Rationality, The Hebrew University of Jerusalem, Givat-Ram, Jerusalem, Israel
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19
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Libbrecht R, Nadrau D, Foitzik S. A Role of Histone Acetylation in the Regulation of Circadian Rhythm in Ants. iScience 2020; 23:100846. [PMID: 32004990 PMCID: PMC6995257 DOI: 10.1016/j.isci.2020.100846] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 12/03/2019] [Accepted: 01/13/2020] [Indexed: 12/15/2022] Open
Abstract
In many organisms, circadian rhythms and associated oscillations in gene expression are controlled by post-translational modifications of histone proteins. Although epigenetic mechanisms influence key aspects of insect societies, their implication in regulating circadian rhythms has not been studied in social insects. Here we ask whether histone acetylation plays a role in adjusting circadian activity in the ant Temnothorax longispinosus. We characterized activity patterns in 20 colonies to reveal that these ants exhibit a diurnal rhythm in colony-level activity and can rapidly respond to changes in the light regime. Then we fed T. longispinosus colonies with C646, a chemical inhibitor of histone acetyltransferases, to show that treated colonies lost their circadian rhythmicity and failed to adjust their activity to the light regime. These findings suggest a role for histone acetylation in controlling rhythmicity in ants and implicate epigenetic processes in the regulation of circadian rhythms in a social context.
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Affiliation(s)
- Romain Libbrecht
- Institute of Organismic and Molecular Evolution (IOME), Johannes Gutenberg University Mainz, Biozentrum I, Hanns Dieter Hüsch Weg 15, 55128 Mainz, Germany.
| | - Dennis Nadrau
- Institute of Organismic and Molecular Evolution (IOME), Johannes Gutenberg University Mainz, Biozentrum I, Hanns Dieter Hüsch Weg 15, 55128 Mainz, Germany
| | - Susanne Foitzik
- Institute of Organismic and Molecular Evolution (IOME), Johannes Gutenberg University Mainz, Biozentrum I, Hanns Dieter Hüsch Weg 15, 55128 Mainz, Germany
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20
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Helfrich-Förster C. Light input pathways to the circadian clock of insects with an emphasis on the fruit fly Drosophila melanogaster. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 206:259-272. [PMID: 31691095 PMCID: PMC7069913 DOI: 10.1007/s00359-019-01379-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/19/2019] [Accepted: 10/26/2019] [Indexed: 12/26/2022]
Abstract
Light is the most important Zeitgeber for entraining animal activity rhythms to the 24-h day. In all animals, the eyes are the main visual organs that are not only responsible for motion and colour (image) vision, but also transfer light information to the circadian clock in the brain. The way in which light entrains the circadian clock appears, however, variable in different species. As do vertebrates, insects possess extraretinal photoreceptors in addition to their eyes (and ocelli) that are sometimes located close to (underneath) the eyes, but sometimes even in the central brain. These extraretinal photoreceptors contribute to entrainment of their circadian clocks to different degrees. The fruit fly Drosophila melanogaster is special, because it expresses the blue light-sensitive cryptochrome (CRY) directly in its circadian clock neurons, and CRY is usually regarded as the fly’s main circadian photoreceptor. Nevertheless, recent studies show that the retinal and extraretinal eyes transfer light information to almost every clock neuron and that the eyes are similarly important for entraining the fly’s activity rhythm as in other insects, or more generally spoken in other animals. Here, I compare the light input pathways between selected insect species with a focus on Drosophila’s special case.
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21
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Beer K, Kolbe E, Kahana NB, Yayon N, Weiss R, Menegazzi P, Bloch G, Helfrich-Förster C. Pigment-Dispersing Factor-expressing neurons convey circadian information in the honey bee brain. Open Biol 2019; 8:rsob.170224. [PMID: 29321240 PMCID: PMC5795053 DOI: 10.1098/rsob.170224] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 12/07/2017] [Indexed: 11/12/2022] Open
Abstract
Pigment-Dispersing Factor (PDF) is an important neuropeptide in the brain circadian network of Drosophila and other insects, but its role in bees in which the circadian clock influences complex behaviour is not well understood. We combined high-resolution neuroanatomical characterizations, quantification of PDF levels over the day and brain injections of synthetic PDF peptide to study the role of PDF in the honey bee Apis mellifera We show that PDF co-localizes with the clock protein Period (PER) in a cluster of laterally located neurons and that the widespread arborizations of these PER/PDF neurons are in close vicinity to other PER-positive cells (neurons and glia). PDF-immunostaining intensity oscillates in a diurnal and circadian manner with possible influences for age or worker task on synchrony of oscillations in different brain areas. Finally, PDF injection into the area between optic lobes and the central brain at the end of the subjective day produced a consistent trend of phase-delayed circadian rhythms in locomotor activity. Altogether, these results are consistent with the hypothesis that PDF is a neuromodulator that conveys circadian information from pacemaker cells to brain centres involved in diverse functions including locomotion, time memory and sun-compass orientation.
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Affiliation(s)
- Katharina Beer
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Esther Kolbe
- Institute of Zoology, University of Regensburg, Universitätsstraße 31, 93040 Regensburg, Germany
| | - Noa B Kahana
- Department of Ecology, Evolution, and Behaviour, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Nadav Yayon
- Department of Ecology, Evolution, and Behaviour, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Ron Weiss
- Department of Ecology, Evolution, and Behaviour, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Pamela Menegazzi
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Guy Bloch
- Department of Ecology, Evolution, and Behaviour, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Charlotte Helfrich-Förster
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
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23
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Shah A, Jain R, Brockmann A. Egr-1: A Candidate Transcription Factor Involved in Molecular Processes Underlying Time-Memory. Front Psychol 2018; 9:865. [PMID: 29928241 PMCID: PMC5997935 DOI: 10.3389/fpsyg.2018.00865] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 05/14/2018] [Indexed: 11/16/2022] Open
Abstract
In honey bees, continuous foraging is accompanied by a sustained up-regulation of the immediate early gene Egr-1 (early growth response protein-1) and candidate downstream genes involved in learning and memory. Here, we present a series of feeder training experiments indicating that Egr-1 expression is highly correlated with the time and duration of training even in the absence of the food reward. Foragers that were trained to visit a feeder over the whole day and then collected on a day without food presentation showed Egr-1 up-regulation over the whole day with a peak expression around 14:00. When exposed to a time-restricted feeder presentation, either 2 h in the morning or 2 h in the evening, Egr-1 expression in the brain was up-regulated only during the hours of training. Foragers that visited a feeder in the morning as well as in the evening showed two peaks of Egr-1 expression. Finally, when we prevented time-trained foragers from leaving the colony using artificial rain, Egr-1 expression in the brains was still slightly but significantly up-regulated around the time of feeder training. In situ hybridization studies showed that active foraging and time-training induced Egr-1 up-regulation occurred in the same brain areas, preferentially the small Kenyon cells of the mushroom bodies and the antennal and optic lobes. Based on these findings we propose that foraging induced Egr-1 expression can get regulated by the circadian clock after time-training over several days and Egr-1 is a candidate transcription factor involved in molecular processes underlying time-memory.
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Affiliation(s)
- Aridni Shah
- Tata Institute of Fundamental Research, National Centre for Biological Sciences, Bengaluru, India
| | - Rikesh Jain
- School of Chemical and Biotechnology, SASTRA University, Thanjavur, India
| | - Axel Brockmann
- Tata Institute of Fundamental Research, National Centre for Biological Sciences, Bengaluru, India
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24
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The role of the circadian clock system in physiology. Pflugers Arch 2018; 470:227-239. [PMID: 29302752 DOI: 10.1007/s00424-017-2103-y] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 12/20/2017] [Indexed: 12/28/2022]
Abstract
Life on earth is shaped by the 24-h rotation of our planet around its axes. To adapt behavior and physiology to the concurring profound but highly predictable changes, endogenous circadian clocks have evolved that drive 24-h rhythms in invertebrate and vertebrate species. At the molecular level, circadian clocks comprised a set of clock genes organized in a system of interlocked transcriptional-translational feedback loops. A ubiquitous network of cellular central and peripheral tissue clocks coordinates physiological functions along the day through activation of tissue-specific transcriptional programs. Circadian rhythms impact on diverse physiological processes including the cardiovascular system, energy metabolism, immunity, hormone secretion, and reproduction. This review summarizes our current understanding of the mechanisms of circadian timekeeping in different species, its adaptation by external timing signals and the pathophysiological consequences of circadian disruption.
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25
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Helm B, Visser ME, Schwartz W, Kronfeld-Schor N, Gerkema M, Piersma T, Bloch G. Two sides of a coin: ecological and chronobiological perspectives of timing in the wild. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160246. [PMID: 28993490 PMCID: PMC5647273 DOI: 10.1098/rstb.2016.0246] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/20/2017] [Indexed: 12/19/2022] Open
Abstract
Most processes within organisms, and most interactions between organisms and their environment, have distinct time profiles. The temporal coordination of such processes is crucial across levels of biological organization, but disciplines differ widely in their approaches to study timing. Such differences are accentuated between ecologists, who are centrally concerned with a holistic view of an organism in relation to its external environment, and chronobiologists, who emphasize internal timekeeping within an organism and the mechanisms of its adjustment to the environment. We argue that ecological and chronobiological perspectives are complementary, and that studies at the intersection will enable both fields to jointly overcome obstacles that currently hinder progress. However, to achieve this integration, we first have to cross some conceptual barriers, clarifying prohibitively inaccessible terminologies. We critically assess main assumptions and concepts in either field, as well as their common interests. Both approaches intersect in their need to understand the extent and regulation of temporal plasticity, and in the concept of 'chronotype', i.e. the characteristic temporal properties of individuals which are the targets of natural and sexual selection. We then highlight promising developments, point out open questions, acknowledge difficulties and propose directions for further integration of ecological and chronobiological perspectives through Wild Clock research.This article is part of the themed issue 'Wild Clocks: integrating chronobiology and ecology to understand timekeeping in free-living animals'.
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Affiliation(s)
- Barbara Helm
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Graham Kerr Building, Glasgow G128QQ, UK
| | - Marcel E Visser
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), PO 50, 6700 AB Wageningen, The Netherlands
| | - William Schwartz
- Department of Neurology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA, USA
| | | | - Menno Gerkema
- Chronobiology, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
| | - Theunis Piersma
- NIOZ Royal Netherlands Institute for Sea Research, Department of Coastal Systems and Utrecht University, 1790 AB Den Burg, Texel, The Netherlands
- Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
| | - Guy Bloch
- Department of Ecology, Evolution, and Behavior, The A. Silberman Institute of Life Sciences, Hebrew University, Jerusalem 91904, Israel
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Nagari M, Szyszka P, Galizia G, Bloch G. Task-Related Phasing of Circadian Rhythms in Antennal Responsiveness to Odorants and Pheromones in Honeybees. J Biol Rhythms 2017; 32:593-608. [PMID: 28984167 DOI: 10.1177/0748730417733573] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The insect antennae receive olfactory information from the environment. In some insects, it has been shown that antennal responsiveness is dynamically regulated by circadian clocks. However, it is unknown how general this phenomenon is and what functions it serves. Circadian regulation in honeybee workers is particularly interesting in this regard because they show natural task-related chronobiological plasticity. Forager bees show strong circadian rhythms in behavior and brain gene expression, whereas nurse bees tend brood around-the-clock and have attenuated circadian rhythms in activity and whole-brain gene expression. Here, we tested the hypothesis that there is task-related plasticity in circadian rhythms of antennal responsiveness to odorants in worker honeybees. We used electroantennogram (EAG) to measure the antennal responsiveness of nurses and foragers to general odorants and pheromones around the day. The capacity to track 10-Hz odorant pulses varied with time of day for both task groups but with different phases. The antennal pulse-tracking capacity was higher during the subjective day for the day-active foragers, whereas it was better during the night for around-the-clock active nurses. The task-related phases of pulse-tracking rhythms were similar for all the tested stimuli. We also found evidence for circadian rhythms in the EAG response magnitude of foragers but not of nurses. To the best of our knowledge, these results provide the first evidence for circadian regulation of antennal olfactory responsiveness and odorant pulse-tracking capacity in bees or any other hymenopteran insect. Importantly, our study shows for the first time that the circadian phase of olfactory responsiveness may be socially regulated.
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Affiliation(s)
- Moshe Nagari
- Department of Ecology, Evolution, and Behavior, The A. Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Paul Szyszka
- Department of Neuroscience, University of Konstanz, Germany
| | | | - Guy Bloch
- Department of Ecology, Evolution, and Behavior, The A. Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
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