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Contala ML, Krapf P, Steiner FM, Schlick-Steiner BC. Foraging valor linked with aggression: selection against completely abandoning aggression in the high-elevation ant Tetramorium alpestre? INSECT SCIENCE 2024; 31:953-970. [PMID: 37602971 DOI: 10.1111/1744-7917.13263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 06/29/2023] [Accepted: 07/12/2023] [Indexed: 08/22/2023]
Abstract
Aggression has multiple benefits and is often coupled with other behaviors ("behavioral syndromes"). The level of aggressiveness is influenced by an adaptive benefit-cost ratio suggesting that benefits should outweigh the costs of aggression. Here, we assess if several behaviors are coupled in two behaviorally different populations (aggressive, peaceful) of the high-elevation ant Tetramorium alpestre. For three weeks, we collected colony fragments and analyzed boldness, exploring, foraging, and risk-taking behaviors. We hypothesized that the aggressive population is bolder, more explorative and risk-prone, and forages more food than the peaceful population. To test whether (a) the combination of experiments and parameters used yields a good setup, (b) populations differ behaviorally, and (c) populations display behavioral syndromes, we assessed (a) the frequency of repeatable behaviors of each experiment, (b) the behavioral means among populations, and (c) the behavioral repeatability, respectively. We found that (a) boldness and exploring were most repeatable and represent a good experimental setup, (b) the aggressive population was bolder and more explorative and risk-prone than the peaceful population, (c) boldness and exploring behaviors were highly repeatable in both populations, thus corroborating our hypothesis. The results suggest that boldness, exploring, and risk-taking but not foraging are presumably coupled with aggression and indicate the presence of behavioral syndromes in this ant. Under specific ecological conditions, aggression may be coupled with other behaviors and important for finding food. Aggression is probably adaptive in T. alpestre, possibly indicating that selection favors aggression at least partially, which may counteract the complete loss of intraspecific aggression.
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Affiliation(s)
- Marie-Luise Contala
- Molecular Ecology Group, Department of Ecology, Universität Innsbruck, Innsbruck, Austria
| | - Patrick Krapf
- Molecular Ecology Group, Department of Ecology, Universität Innsbruck, Innsbruck, Austria
- Organismal & Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland
| | - Florian M Steiner
- Molecular Ecology Group, Department of Ecology, Universität Innsbruck, Innsbruck, Austria
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Ferguson ST, Bakis I, Edwards ND, Zwiebel LJ. Age and Task Modulate Olfactory Sensitivity in the Florida Carpenter Ant Camponotus floridanus. INSECTS 2023; 14:724. [PMID: 37754692 PMCID: PMC10532128 DOI: 10.3390/insects14090724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 08/08/2023] [Accepted: 08/16/2023] [Indexed: 09/28/2023]
Abstract
Age-related changes in behavior and sensory perception have been observed in a wide variety of animal species. In ants and other eusocial insects, workers often progress through an ordered sequence of olfactory-driven behavioral tasks. Notably, these behaviors are plastic, and workers adapt and rapidly switch tasks in response to changing environmental conditions. In the Florida carpenter ant, smaller minors typically perform most of the work needed to maintain the colony, while the larger majors are specialized for nest defense and rarely engage in these routine tasks. Here, we investigate the effects of age and task group on olfactory responses to a series of odorant blends in minor and major worker castes. Consistent with their respective roles within the colony, we observed significant age-associated shifts in the olfactory responses of minors as they transitioned between behavioral states, whereas the responses of majors remained consistently low regardless of age. Furthermore, we have identified a unitary compound, 3-methylindole, which elicited significantly higher responses and behavioral aversion in minor nurses than in similarly aged foragers suggesting that this compound may play an important role in brood care. Taken together, our results suggest that age- and task-associated shifts in olfactory physiology may play a critical role in the social organization of ant colonies.
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Affiliation(s)
| | | | | | - Laurence J. Zwiebel
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA; (S.T.F.); (I.B.); (N.D.E.)
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3
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Ferguson ST, Bakis I, Edwards ND, Zwiebel LJ. Age and Task Modulate Olfactory Sensitivity in the Florida Carpenter Ant Camponotus floridanus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.18.549561. [PMID: 37503123 PMCID: PMC10370051 DOI: 10.1101/2023.07.18.549561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Age-related changes in behavior and sensory perception have been observed in a wide variety of animal species. In ants and other eusocial insects, workers often progress through an ordered sequence of olfactory-driven behavioral tasks. Notably, these behaviors are plastic, and workers adapt and rapidly switch tasks in response to changing environmental conditions. In the Florida carpenter ant, smaller minors typically perform most of the work needed to maintain the colony while the larger majors are specialized for nest defense and rarely engage in these routine tasks. Here, we investigate the effects of age and task group on olfactory responses to a series of odorant blends in minor and major worker castes. Consistent with their respective roles within the colony, we observed significant age-associated shifts in the olfactory responses of minors as they transitioned between behavioral states, whereas the responses of majors remained consistently low regardless of age. Furthermore, we identified a unitary compound, 3-methylindole, which elicited significantly higher responses and behavioral aversion in minor nurses than in similarly aged foragers suggesting that this compound may play an important role in brood care. Taken together, our results suggest that age- and task-associated shifts in olfactory physiology may play a critical role in the social organization of ant colonies. Simple Summary Florida carpenter ants ( Camponotus floridanus ) live in colonies comprised of thousands of workers. The smallest workers, known as minors, engage in routine tasks such as nursing and foraging while the largest workers, known as majors, are thought to be soldiers specialized for defending the nest. How ant colonies allocate their workforce to address the dynamic and ever-changing needs of the colonies remains an open question in the field, but current evidence suggests that ant social behavior likely results from a combination of genetic/epigenetic, physiological, and systems-level processes. Here, we extend these studies by investigating the role of olfactory sensitivity in regulating ant behavior. Minor workers exhibited significant shifts in olfactory sensitivity and odor coding as they aged and switched tasks. The olfactory sensitivity of majors, however, remained relatively stable as they aged. From these studies, we also identified a single compound, 3-methylindole, which elicited significantly higher olfactory responses and aversive behavior in nurses compared to foragers, suggesting that this chemical may have a role in brood care. Overall, these studies support the hypothesis that changes in olfactory sensitivity play an important role in regulating social behavior in ants.
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Barbero F, Mannino G, Casacci LP. The Role of Biogenic Amines in Social Insects: With a Special Focus on Ants. INSECTS 2023; 14:386. [PMID: 37103201 PMCID: PMC10142254 DOI: 10.3390/insects14040386] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 04/12/2023] [Accepted: 04/13/2023] [Indexed: 06/19/2023]
Abstract
Eusociality represents the higher degree of interaction in insects. This complex social structure is maintained through a multimodal communication system that allows colony members to be flexible in their responses, fulfilling the overall society's needs. The colony plasticity is supposedly achieved by combining multiple biochemical pathways through the neuromodulation of molecules such as biogenic amines, but the mechanisms through which these regulatory compounds act are far from being fully disentangled. Here, we review the potential function of major bioamines (dopamine, tyramine, serotine, and octopamine) on the behavioral modulation of principal groups of eusocial Hymenoptera, with a special focus on ants. Because functional roles are species- and context-dependent, identifying a direct causal relationship between a biogenic amine variation and behavioral changes is extremely challenging. We also used a quantitative and qualitative synthesis approach to summarize research trends and interests in the literature related to biogenic amines of social insects. Shedding light on the aminergic regulation of behavioral responses will pave the way for an entirely new approach to understanding the evolution of sociality in insects.
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Affiliation(s)
- Francesca Barbero
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Turin, Italy;
| | - Giuseppe Mannino
- Department of Life Sciences and Systems Biology, University of Turin, Via Gioacchino Quarello 15/A, 10135 Turin, Italy;
| | - Luca Pietro Casacci
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Turin, Italy;
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Ferguson ST, Bakis I, Edwards ND, Zwiebel LJ. Olfactory sensitivity differentiates morphologically distinct worker castes in Camponotus floridanus. BMC Biol 2023; 21:3. [PMID: 36617574 PMCID: PMC9827628 DOI: 10.1186/s12915-022-01505-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 12/08/2022] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Camponotus floridanus ant colonies are comprised of a single reproductive queen and thousands of sterile female offspring that consist of two morphologically distinct castes: smaller minors and larger majors. Minors perform most of the tasks within the colony, including brood care and food collection, whereas majors have fewer clear roles and have been hypothesized to act as a specialized solider caste associated with colony defense. The allocation of workers to these different tasks depends, in part, on the detection and processing of local information including pheromones and other chemical blends such as cuticular hydrocarbons. However, the role peripheral olfactory sensitivity plays in establishing and maintaining morphologically distinct worker castes and their associated behaviors remains largely unexplored. RESULTS We examined the electrophysiological responses to general odorants, cuticular extracts, and a trail pheromone in adult minor and major C. floridanus workers, revealing that the repertoire of social behaviors is positively correlated with olfactory sensitivity. Minors in particular display primarily excitatory responses to olfactory stimuli, whereas major workers primarily manifest suppressed, sub-solvent responses. The notable exception to this paradigm is that both minors and majors display robust, dose-dependent excitatory responses to conspecific, non-nestmate cuticular extracts. Moreover, while both minors and majors actively aggress non-nestmate foes, the larger and physiologically distinct majors display significantly enhanced capabilities to rapidly subdue and kill their adversaries. CONCLUSIONS Our studies reveal the behavioral repertoire of minors and majors aligns with profound shifts in peripheral olfactory sensitivity and odor coding. The data reported here support the hypothesis that minors are multipotential workers with broad excitatory sensitivity, and majors are dedicated soldiers with a highly specialized olfactory system for distinguishing non-nestmate foes. Overall, we conclude that C. floridanus majors do indeed represent a physiologically and behaviorally specialized soldier caste in which caste-specific olfactory sensitivity plays an important role in task allocation and the regulation of social behavior in ant colonies.
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Affiliation(s)
- S. T. Ferguson
- grid.152326.10000 0001 2264 7217Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235 USA
| | - I. Bakis
- grid.152326.10000 0001 2264 7217Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235 USA
| | - N. D. Edwards
- grid.152326.10000 0001 2264 7217Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235 USA
| | - L. J. Zwiebel
- grid.152326.10000 0001 2264 7217Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235 USA
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Frankel TE, Frankel JS. Sulfoxaflor causes mortality, decreased locomotion, and altered interactions in pavement ants ( Tetramorium caespitum). JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART. B, PESTICIDES, FOOD CONTAMINANTS, AND AGRICULTURAL WASTES 2021; 56:891-898. [PMID: 34486931 DOI: 10.1080/03601234.2021.1973837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
This study investigated the exposure effects of sulfoxaflor, a next-generation sulfoximine insecticide, on the viability, locomotor behavior, and nest-mate interactions of the pavement ant (Tetramorium caespitum). Adult worker ants were exposed to 0, 1, 5, 12.5, 25, or 50 mg/L of sulfoxaflor via oral ingestion for 48 h. This short-term exposure to concentrations as low as 1 mg/L had wide ranging effects on multiple locomotive parameters (average speed, mobile average speed, total travel distance), nest-mate interactions (aggression and antennation), and body morphology (abdominal curving). Exposure to sulfoxaflor for 24 h manifested in decreased locomotion, altered intraspecific interactions and the development of abdominal curvature in the 25 and 50 mg/L treatments. Such alterations in mobility and conspecific behavioral parameters would clearly impact the ability of exposed individuals to successfully satisfy resource demands and presents a risk to colony survival.
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Affiliation(s)
- Tyler E Frankel
- Department of Earth and Environmental Sciences, University of Mary Washington, Fredericksburg, VA, USA
| | - Jack S Frankel
- Department of Biology, Howard University, Washington, DC, USA
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Hsieh HW, Chen SC, Huang WC, Fang S, Yang EC, Hsu CC, Kou R. Social interactions upregulate hemolymph tryptophan and tyrosine levels in the male lobster cockroach. Horm Behav 2021; 130:104935. [PMID: 33497707 DOI: 10.1016/j.yhbeh.2021.104935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 01/10/2021] [Accepted: 01/11/2021] [Indexed: 10/22/2022]
Abstract
In the present study, we found that tryptophan (TRP) and tyrosine (TYR) levels are increased in hemolymph of male Nauphoeta cinerea after social contact with either male or female conspecifics. Hemolymph was collected from individual males before and after the social interactions, and samples were analyzed by HPLC-ECD; analyte identities were confirmed by UPLC/MS. After a male-male first encounter fight, hemolymph TRP and TYR levels were significantly increased in dominants compared with the levels before the encounter. Conversely, TRP and TYR in subordinates were maintained at levels similar to those before the encounter. While after-fight TRP and TYR levels were significantly higher in dominants than subordinates, no significant differences were found in the contestants before the fight. Moreover, contact with an isolated male antenna was sufficient to stimulate attack behavior and increase hemolymph TRP and TYR titers to levels similar to those seen in dominants. After a male-female interaction, two distinct outcomes could be observed. Either hemolymph TRP and TYR levels were increased in successfully mated males, or TRP and TYR levels were unchanged in males that only exhibited premating wing-raising behavior but failed in mating. After contacting the antenna of a socially naïve male with an isolated female antenna, three patterns of behavior and related amino acid response were observed: 1) only premating wing-raising behavior with significant increase of TRP and TYR levels, 2) only attack behavior with significant increase of TRP and TYR levels, and 3) mixed wing-raising and attack behaviors with no significant changes in TRP and TYR levels. The present results show a robust response of hemolymph TRP and TYR to social contact. In light of previously characterized responses in pheromone and juvenile hormone levels, these amine responses suggest that the physiological response of N. cinerea to social contact is multi-dimensional.
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Affiliation(s)
- Hsiang-Wen Hsieh
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Shu-Chun Chen
- Institute of Statistical Science, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Wan-Chen Huang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Shu Fang
- Biodiversity Research Center, Academia Sinica, Taipei 115, Taiwan, ROC
| | - En-Cheng Yang
- Department of Entomology, National Taiwan University, Taipei, Taiwan, ROC
| | - Chu-Chun Hsu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan, ROC
| | - Rong Kou
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan, ROC.
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8
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Behavioural Changes in Mice after Getting Accustomed to the Mirror. Behav Neurol 2020; 2020:4071315. [PMID: 32089750 PMCID: PMC7023847 DOI: 10.1155/2020/4071315] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 01/14/2020] [Indexed: 01/18/2023] Open
Abstract
Patients with brain function disorders due to stroke or dementia may show inability to recognize themselves in the mirror. Although the cognitive ability to recognize mirror images has been investigated in many animal species, the animal species that can be used for experimentation and the mechanisms involved in recognition remain unclear. We investigated whether mice have the ability to recognize their mirror images. Demonstrating evidence of this in mice would be useful for researching the psychological and biological mechanisms underlying this ability. We examined whether mice preferred mirrors, whether plastic tapes on their heads increased their interest, and whether mice accustomed to mirrors learnt its physical phenomenon. Mice were significantly more interested in live stranger mice than mirrors. Mice with tape on their heads spent more time before mirrors. Becoming accustomed to mirrors did not change their behaviour. Mice accustomed to mirrors had significantly increased interest in photos of themselves over those of strangers and cage-mates. These results indicated that mice visually recognized plastic tape adherent to reflected individuals. Mice accustomed to mirrors were able to discriminate between their images, cage-mates, and stranger mice. However, it is still unknown whether mice recognize that the reflected images are of themselves.
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9
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Bubak AN, Watt MJ, Yaeger JDW, Renner KJ, Swallow JG. The stalk-eyed fly as a model for aggression - is there a conserved role for 5-HT between vertebrates and invertebrates? ACTA ACUST UNITED AC 2020; 223:223/1/jeb132159. [PMID: 31896721 DOI: 10.1242/jeb.132159] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Serotonin (5-HT) has largely been accepted to be inhibitory to vertebrate aggression, whereas an opposing stimulatory role has been proposed for invertebrates. Herein, we argue that critical gaps in our understanding of the nuanced role of 5-HT in invertebrate systems drove this conclusion prematurely, and that emerging data suggest a previously unrecognized level of phylogenetic conservation with respect to neurochemical mechanisms regulating the expression of aggressive behaviors. This is especially apparent when considering the interplay among factors governing 5-HT activity, many of which share functional homology across taxa. We discuss recent findings using insect models, with an emphasis on the stalk-eyed fly, to demonstrate how particular 5-HT receptor subtypes mediate the intensity of aggression with respect to discrete stages of the interaction (initiation, escalation and termination), which mirrors the complex behavioral regulation currently recognized in vertebrates. Further similarities emerge when considering the contribution of neuropeptides, which interact with 5-HT to ultimately determine contest progression and outcome. Relative to knowledge in vertebrates, much less is known about the function of 5-HT receptors and neuropeptides in invertebrate aggression, particularly with respect to sex, species and context, prompting the need for further studies. Our Commentary highlights the need to consider multiple factors when determining potential taxonomic differences, and raises the possibility of more similarities than differences between vertebrates and invertebrates with regard to the modulatory effect of 5-HT on aggression.
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Affiliation(s)
- Andrew N Bubak
- Department of Neurology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Michael J Watt
- Department of Anatomy, University of Otago, Dunedin 9016, New Zealand
| | - Jazmine D W Yaeger
- Department of Biology, University of South Dakota, Vermillion, SD 57069, USA
| | - Kenneth J Renner
- Department of Biology, University of South Dakota, Vermillion, SD 57069, USA
| | - John G Swallow
- Department of Integrative Biology, University of Colorado-Denver, Denver, CO 80217, USA
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10
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Sun P, Yu S, Merchant A, Lei C, Zhou X, Huang Q. Downregulation of Orco and 5-HTT Alters Nestmate Discrimination in the Subterranean Termite Odontotermes formosanus (Shiraki). Front Physiol 2019; 10:714. [PMID: 31244679 PMCID: PMC6579916 DOI: 10.3389/fphys.2019.00714] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 05/23/2019] [Indexed: 01/09/2023] Open
Abstract
Nestmate discrimination allows social insects to recognize nestmates from non-nestmates using colony-specific chemosensory cues, which typically evoke aggressive behavior toward non-nestmates. Functional analysis of genes associated with nestmate discrimination has been primarily focused on inter-colonial discrimination in Hymenopterans, and parallel studies in termites, however, are grossly lacking. To fill this gap, we investigated the role of two genes, Orco and 5-HTT, associated with chemosensation and neurotransmission respectively, in nestmate discrimination in a highly eusocial subterranean termite, Odontotermes formosanus (Shiraki). We hypothesized that knocking down of these genes will compromise the nestmate recognition and lead to the antagonistic behavior. To test this hypothesis, we carried out (1) an in vivo RNAi to suppress the expression of Orco and 5-HTT, respectively, (2) a validation study to examine the knockdown efficiency, and finally, (3) a behavioral assay to document the phenotypic impacts/behavioral consequences. As expected, the suppression of either of these two genes elevated stress level (e.g., vibrations and retreats), and led to aggressive behaviors (e.g., biting) in O. formosanus workers toward their nestmates, suggesting both Orco and 5-HTT can modulate nestmate discrimination in termites. This research links chemosensation and neurotransmission with nestmate discrimination at the genetic basis, and lays the foundation for functional analyses of nestmate discrimination in termites.
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Affiliation(s)
- Pengdong Sun
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Shuxin Yu
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Austin Merchant
- Department of Entomology, University of Kentucky, Lexington, KY, United States
| | - Chaoliang Lei
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xuguo Zhou
- Department of Entomology, University of Kentucky, Lexington, KY, United States
| | - Qiuying Huang
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
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11
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Ramesh D, Brockmann A. Mass Spectrometric Quantification of Arousal Associated Neurochemical Changes in Single Honey Bee Brains and Brain Regions. ACS Chem Neurosci 2019; 10:1950-1959. [PMID: 30346719 DOI: 10.1021/acschemneuro.8b00254] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Honey bee foragers show a strong diurnal rhythm of foraging activity, and such behavioral changes are likely under the control of specific neuromodulators. To identify and quantify neuromodulators involved in regulating rest and arousal in honey bees, we established a mass spectrometric method for quantifying 14 different neurochemicals and precursor molecules. We measured forager type and brain region specific differences in amine levels from individual honey bee brains and brain regions. The observed differences in amine levels between resting and aroused foragers resemble findings in other species indicating a conserved molecular mechanism by glutamate and GABA in regulating arousal. Subesophageal ganglion specific changes in the histaminergic system and global increases in aspartate during arousal suggest a possible role of histamine and aspartate in feeding and arousal, respectively. More aminergic systems were significantly affected due to arousal in nectar foragers than in pollen foragers, implying that forager phenotypes differ not only in their food preference but also in their neuromodulatory signaling systems (brain states). Finally, we found that neurotransmitter precursors were better at distinguishing brain states in the central brain, while their end products correlated with arousal associated changes in sensory regions like the optic and antennal lobes.
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Affiliation(s)
- Divya Ramesh
- National Centre for Biological Sciences, Bangalore 560065 Karnataka, India
| | - Axel Brockmann
- National Centre for Biological Sciences, Bangalore 560065 Karnataka, India
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12
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Bubak AN, Watt MJ, Renner KJ, Luman AA, Costabile JD, Sanders EJ, Grace JL, Swallow JG. Sex differences in aggression: Differential roles of 5-HT2, neuropeptide F and tachykinin. PLoS One 2019; 14:e0203980. [PMID: 30695038 PMCID: PMC6350964 DOI: 10.1371/journal.pone.0203980] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 01/15/2019] [Indexed: 11/18/2022] Open
Abstract
Despite the conserved function of aggression across taxa in obtaining critical resources such as food and mates, serotonin's (5-HT) modulatory role on aggressive behavior appears to be largely inhibitory for vertebrates but stimulatory for invertebrates. However, critical gaps exist in our knowledge of invertebrates that need to be addressed before definitively stating opposing roles for 5-HT and aggression. Specifically, the role of 5-HT receptor subtypes are largely unknown, as is the potential interactive role of 5-HT with other neurochemical systems known to play a critical role in aggression. Similarly, the influence of these systems in driving sex differences in aggressive behavior of invertebrates is not well understood. Here, we investigated these questions by employing complementary approaches in a novel invertebrate model of aggression, the stalk-eyed fly. A combination of altered social conditions, pharmacological manipulation and 5-HT2 receptor knockdown by siRNA revealed an inhibitory role of this receptor subtype on aggression. Additionally, we provide evidence for 5-HT2's involvement in regulating neuropeptide F activity, a suspected inhibitor of aggression. However, this function appears to be stage-specific, altering only the initiation stage of aggressive conflicts. Alternatively, pharmacologically increasing systemic concentrations of 5-HT significantly elevated the expression of the neuropeptide tachykinin, which did not affect contest initiation but instead promoted escalation via production of high intensity aggressive behaviors. Notably, these effects were limited solely to males, with female aggression and neuropeptide expression remaining unaltered by any manipulation that affected 5-HT. Together, these results demonstrate a more nuanced role for 5-HT in modulating aggression in invertebrates, revealing an important interactive role with neuropeptides that is more reminiscent of vertebrates. The sex-differences described here also provide valuable insight into the evolutionary contexts of this complex behavior.
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Affiliation(s)
- Andrew N. Bubak
- Department of Neurology, University of Colorado-Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Michael J. Watt
- Center for Brain and Behavior Research, Basic Biomedical Sciences, University of South Dakota, Vermillion, South Dakota, United States of America
| | - Kenneth J. Renner
- Biology Department, University of South Dakota, Vermillion, South Dakota, United States of America
| | - Abigail A. Luman
- Department of Integrative Biology, University of Colorado-Denver, Denver, United States of America
| | - Jamie D. Costabile
- Department of Integrative Biology, University of Colorado-Denver, Denver, United States of America
| | - Erin J. Sanders
- Department of Integrative Biology, University of Colorado-Denver, Denver, United States of America
| | - Jaime L. Grace
- Department of Biology, Bradley University, Peoria, Illinois, United States of America
| | - John G. Swallow
- Department of Integrative Biology, University of Colorado-Denver, Denver, United States of America
- * E-mail:
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13
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Hewlett SE, Delahunt Smoleniec JD, Wareham DM, Pyne TM, Barron AB. Biogenic amine modulation of honey bee sociability and nestmate affiliation. PLoS One 2018; 13:e0205686. [PMID: 30359390 PMCID: PMC6201892 DOI: 10.1371/journal.pone.0205686] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 09/28/2018] [Indexed: 11/18/2022] Open
Abstract
Biogenic amines modulate a range of social behaviours, including sociability and mechanisms of group cohesion, in both vertebrates and invertebrates. Here, we tested if the biogenic amines modulate honey bee (Apis mellifera) sociability and nestmate affiliation. We examined the consequences of treatments with biogenic amines, agonists and antagonists on a bee’s approach to, and subsequent social interactions with, conspecifics in both naturally hive-reared bees and isolated bees. We used two different treatment methods. Bees were first treated topically with compounds dissolved in the solvent dimethylformamide (dMF) applied to the dorsal thorax, but dMF had a significant effect on the locomotion and behaviour of the bees during the behavioural test that interfered with their social responses. Our second method used microinjection to deliver biogenic amines to the head capsule via the ocellar tract. Microinjection of dopamine and a dopamine antagonist had strong effects on bee sociability, likelihood of interaction with bees, and nestmate affiliation. Octopamine treatment reduced social interaction with other bees, and serotonin increased the likelihood of social interactions. HPLC measurements showed that isolation reduced brain levels of biogenic amines compared to hive-reared bees. Our findings suggest that dopamine is an important neurochemical component of social motivation in bees. This finding advances a comparative understanding of the processes of social evolution.
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Affiliation(s)
- Susie E. Hewlett
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
- * E-mail: (SH); (AB)
| | | | - Deborah M. Wareham
- Department of Health Professions, Macquarie University, Sydney, New South Wales, Australia
| | - Thomas M. Pyne
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Andrew B. Barron
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
- * E-mail: (SH); (AB)
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14
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Friedman DA, Pilko A, Skowronska-Krawczyk D, Krasinska K, Parker JW, Hirsh J, Gordon DM. The Role of Dopamine in the Collective Regulation of Foraging in Harvester Ants. iScience 2018; 8:283-294. [PMID: 30270022 PMCID: PMC6205345 DOI: 10.1016/j.isci.2018.09.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 08/04/2018] [Accepted: 09/03/2018] [Indexed: 01/09/2023] Open
Abstract
Colonies of the red harvester ant (Pogonomyrmex barbatus) differ in how they regulate collective foraging activity in response to changes in humidity. We used transcriptomic, physiological, and pharmacological experiments to investigate the molecular basis of this ecologically important variation in collective behavior among colonies. RNA sequencing of forager brain tissue showed an association between colony foraging activity and differential expression of transcripts related to biogenic amine and neurohormonal metabolism and signaling. In field experiments, pharmacological increases in forager brain dopamine titer caused significant increases in foraging activity. Colonies that were naturally most sensitive to humidity were significantly more responsive to the stimulatory effect of exogenous dopamine. In addition, forager brain tissue significantly varied among colonies in biogenic amine content. Neurophysiological variation among colonies associated with individual forager sensitivity to humidity may reflect the heritable molecular variation on which natural selection acts to shape the collective regulation of foraging.
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Affiliation(s)
- Daniel A Friedman
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
| | - Anna Pilko
- Department of Chemistry and Biochemistry and the Institute for Quantitative and Computational Biosciences (QCB), University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Dorota Skowronska-Krawczyk
- Shiley Eye Institute, Richard C. Atkinson Lab for Regenerative Ophthalmology, Department of Ophthalmology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Karolina Krasinska
- Stanford University Mass Spectrometry, Stanford University, Stanford, CA 94305, USA
| | - Jacqueline W Parker
- Department of Biology, University of Virginia, Charlottesville, Charlottesville, VA 22904, USA
| | - Jay Hirsh
- Department of Biology, University of Virginia, Charlottesville, Charlottesville, VA 22904, USA
| | - Deborah M Gordon
- Department of Biology, Stanford University, Stanford, CA 94305, USA
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15
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Adler FR, Quinonez S, Plowes N, Adams ES. Mechanistic Models of Conflict between Ant Colonies and Their Consequences for Territory Scaling. Am Nat 2018; 192:204-216. [PMID: 30016157 DOI: 10.1086/698121] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Territory size in social insects depends on the rules by which border conflicts are resolved. We present three mechanistic mathematical models of conflict, inspired by the behavior of the pavement ant Tetramorium immigrans, to predict the advantage of larger colonies in pairwise contests and the resulting scaling of territory size with worker force. The models track the number of ants in the nest traveling to and from the boundary or engaged at the boundary. Ants at the boundary base their recruitment response on the relative numbers of ants from the two colonies. With two colonies, our central result is that the larger colony gains a territory disproportionately larger than the ratio of worker forces would indicate. This disproportionate territory control determines the scaling relation of territory size with worker force in a population. In two dimensions, if territory size were proportional to worker force, the slope of the scaling relation between log territory size and log worker force would be 1.0. With disproportionate territories, this slope is larger and can be explicitly approximated in terms of model parameters, and it is steepest when colonies are packed close to each other, when ants run quickly, or when colonies are small. A steeper slope exaggerates the advantage of larger colonies, creating a positive feedback that could amplify the inequality of the worker force distribution.
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16
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Verlinden H. Dopamine signalling in locusts and other insects. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 97:40-52. [PMID: 29680287 DOI: 10.1016/j.ibmb.2018.04.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/05/2018] [Accepted: 04/08/2018] [Indexed: 06/08/2023]
Abstract
Dopamine is an important catecholamine neurotransmitter in invertebrates and vertebrates. It is biochemically derived from tyrosine via L-DOPA. It is most abundant in the central nervous system, but can also be produced in e.g. epidermal cells. Dopamine has conserved roles in the control of movement, pleasure, motivation, arousal and memory between invertebrate and vertebrate animals. It is crucial for melanisation and sclerotisation, important processes for the formation of the exoskeleton of insects and immune function. In this brief review I will discuss some general aspects of insect dopamine biosynthesis and breakdown, dopamine receptors and their pharmacology. In addition, I will provide a glance on the multitude of biological functions of dopamine in insects. More detail is provided concerning the putative roles of dopamine in phase related phenomena in locusts. Finally, molecular and pharmacological adjustments of insect dopamine signalling are discussed in the light of possible approaches towards insect pest management.
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Affiliation(s)
- Heleen Verlinden
- Department of Animal Physiology and Neurobiology, Zoological Institute, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium.
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