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Cremer S, Pull CD. Unconditional versus condition-dependent social immunity. Trends Parasitol 2024; 40:780-787. [PMID: 39152078 DOI: 10.1016/j.pt.2024.07.014] [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: 04/26/2024] [Revised: 07/22/2024] [Accepted: 07/22/2024] [Indexed: 08/19/2024]
Abstract
Socially living animals can counteract disease through cooperative defences, leading to social immunity that collectively exceeds the sum of individual defences. In superorganismal colonies of social insects with permanent caste separation between reproductive queen(s) and nonreproducing workers, workers are obligate altruists and thus engage in unconditional social immunity, including highly specialised and self-sacrificial hygiene behaviours. Contrastingly, cooperation is facultative in cooperatively breeding families, where all members are reproductively totipotent but offspring transiently forgo reproduction to help their parents rear more siblings. Here, helpers should either express condition-dependent social immunity or disperse to pursue independent reproduction. We advocate inclusive fitness theory as a framework to predict when and how indirect fitness gains may outweigh direct fitness costs, thus favouring conditional social immunity.
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Affiliation(s)
- Sylvia Cremer
- ISTA (Institute of Science and Technology Austria), Klosterneuburg, Austria.
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2
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Lu X, Wang M, Jiang D, Tang F. The function of OforOrco in the allogrooming behavior of Odontotermes formosanus (Shiraki) induced by Serratia marcescens Bizio (SM1). PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2024; 204:106004. [PMID: 39277353 DOI: 10.1016/j.pestbp.2024.106004] [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: 11/28/2023] [Revised: 06/25/2024] [Accepted: 06/28/2024] [Indexed: 09/17/2024]
Abstract
Termites are consistently confronted with a complex microbial environment. In addition to the role of their innate immune system in resisting pathogen infection, social immune behavior also plays a significant role in helping termites withstand the stress caused by pathogenic microorganisms. The allogrooming behavior among different individuals is commonly observed in termites, and it plays a crucial role in the social immune interaction network. In the case of Odontotermes formosanus (Shiraki), Orco is specifically involved in detecting pheromones and volatile chemicals released by termites to communicate with each other. Nonetheless, the function of Orco in the social immunity remains unreported in O. formosanus. Consequently, in this study, we recorded the allogrooming behavior of O. formosanus workers under SM1 stress. The results indicated a significant increase in allogrooming behavior due to SM1 infection. The allogrooming behavior of workers under SM1 stress was significantly increased after the addition of soldiers. Compared with pronotum group treated by SM1, SM1 treatment of workers' heads significantly reduced the allogrooming behavior among workers. In addition, we found that SM1 could greatly increase the expression of OforOrco. Furthermore, interfering with OforOrco could markedly reduce the allogrooming behavior among workers under SM1 stress, and increase the mortality of worker under SM1 stress. This study demonstrated the significant role of OforOrco in the social immunity of O. formosanus, which offers a theoretical foundation for the advancement of research on termite RNA biopesticides, and the integration of RNA interference (RNAi) with pathogens. This study is valuable for elucidating the social immune behavior and interaction network of termites.
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Affiliation(s)
- Xiaoyu Lu
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, People's Republic of China; College of Forestry and Grassland, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Mingyu Wang
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, People's Republic of China; College of Forestry and Grassland, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Dabao Jiang
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, People's Republic of China; College of Forestry and Grassland, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Fang Tang
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, People's Republic of China; College of Forestry and Grassland, Nanjing Forestry University, Nanjing 210037, People's Republic of China.
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3
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Li H, Liu J, Wang Q, Ma Y, Zhao W, Chen B, Price JH, Zhang D. Oleic acid triggers burial behavior in a termite population through an odorant binding protein. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2024; 167:104090. [PMID: 38369269 DOI: 10.1016/j.ibmb.2024.104090] [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: 12/10/2023] [Revised: 01/28/2024] [Accepted: 02/15/2024] [Indexed: 02/20/2024]
Abstract
Social insects maintain hygienic conditions through their social immunity behaviors. Among these behaviors, burial behavior of termites is central for protecting healthy individuals from corpses. Many factors trigger burial behavior, and it is generally believed that chemicals released by corpses, such as oleic acid, are the most important cues for triggering burial behavior in termites. However, the contribution of the olfactory system to this behavior remains unclear. Here we report an odorant binding protein (OBP) that transports oleic acid and triggers burial behavior in Coptotermes formosanus Shiraki. We demonstrated that CforOBP7 is highly expressed in the antennae of workers. Fluorescent competition binding experiments exhibited that CforOBP7 has a strong affinity for oleic acid. Furthermore, the antennal response to oleic acid was significantly reduced, and oleic acid-triggered burial behavior was also inhibited in CforOBP7-silenced termites. We conclude that CforOBP7 governs the burial behavior of C. formosanus triggered by oleic acid.
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Affiliation(s)
- Hongyue Li
- College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou, China
| | - Jiahan Liu
- College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou, China; College of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, China
| | - Qian Wang
- College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou, China
| | - Yuanfei Ma
- College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou, China
| | - Weisong Zhao
- College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou, China
| | - Bosheng Chen
- College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou, China
| | - Jennifer Hackney Price
- School of Mathematical & Natural Sciences, New College of Interdisciplinary Arts & Sciences, Arizona State University, Phoenix, AZ, USA
| | - Dayu Zhang
- College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou, China.
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4
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Qian C, Wen C, Guo X, Yang X, Wen X, Ma T, Wang C. Gregariousness in lepidopteran larvae. INSECT SCIENCE 2024. [PMID: 38214204 DOI: 10.1111/1744-7917.13312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 10/13/2023] [Accepted: 11/08/2023] [Indexed: 01/13/2024]
Abstract
The gregarious lifestyle of lepidopteran larvae is diverse and shaped by a complex interplay of ecological and evolutionary factors. Our review showed that the larval-aggregation behavior has been reported in 23 lepidopteran families, indicating multiple evolution of this behavior. Some larvae live in sibling groups throughout all larval instars and even pupation stages, which may result from the kin-selection. In contrast, group fusion may occur among different sibling or foraging groups of larvae and form larger aggregates, and the gregariousness of these species might be driven by the group-selection. While group size and foraging patterns vary greatly across species, it is generally associated with improved larval survivorship and accelerated development. However, the advantages of group living, such as facilitating feeding activities, adjusting the temperature, and defending natural enemies, may diminish along with development, with strong intraspecific competition occurring at later instars, even when food is abundant. Therefore, the group sizes and fission-fusion dynamics of certain gregarious lepidopteran larvae may be a consequence of their cost-benefit balance depending on various biotic and abiotic factors. Trail and aggregation pheromones, silk trails, or body contact contribute to collective movement and group cohesion of gregarious lepidopteran larvae. However, frequent contact among group members may cause the horizontal transmission of pathogens and pesticides, which may bring an integrated pest management strategy controlling gregarious lepidopteran pests.
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Affiliation(s)
- Chenyu Qian
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Chao Wen
- School of Grassland Science, Beijing Forestry University, Beijing, China
| | - Xiaoli Guo
- Beijing Key Laboratory for Forest Pest Control, Beijing Forestry University, Beijing, China
| | - Xinya Yang
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Xiujun Wen
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Tao Ma
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Cai Wang
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
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5
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Jiang S, Marco HG, Scheich N, He S, Wang Z, Gäde G, McMahon DP. Comparative analysis of adipokinetic hormones and their receptors in Blattodea reveals novel patterns of gene evolution. INSECT MOLECULAR BIOLOGY 2023; 32:615-633. [PMID: 37382487 DOI: 10.1111/imb.12861] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/18/2023] [Indexed: 06/30/2023]
Abstract
Adipokinetic hormone (AKH) is a neuropeptide produced in the insect corpora cardiaca that plays an essential role in mobilising carbohydrates and lipids from the fat body to the haemolymph. AKH acts by binding to a rhodopsin-like G protein-coupled receptor (GPCR), the adipokinetic hormone receptor (AKHR). In this study, we tackle AKH ligand and receptor gene evolution as well as the evolutionary origins of AKH gene paralogues from the order Blattodea (termites and cockroaches). Phylogenetic analyses of AKH precursor sequences point to an ancient AKH gene duplication event in the common ancestor of Blaberoidea, yielding a new group of putative decapeptides. In total, 16 different AKH peptides from 90 species were obtained. Two octapeptides and seven putatively novel decapeptides are predicted for the first time. AKH receptor sequences from 18 species, spanning solitary cockroaches and subsocial wood roaches as well as lower and higher termites, were subsequently acquired using classical molecular methods and in silico approaches employing transcriptomic data. Aligned AKHR open reading frames revealed 7 highly conserved transmembrane regions, a typical arrangement for GPCRs. Phylogenetic analyses based on AKHR sequences support accepted relationships among termite, subsocial (Cryptocercus spp.) and solitary cockroach lineages to a large extent, while putative post-translational modification sites do not greatly differ between solitary and subsocial roaches and social termites. Our study provides important information not only for AKH and AKHR functional research but also for further analyses interested in their development as potential candidates for biorational pest control agents against invasive termites and cockroaches.
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Affiliation(s)
- Shixiong Jiang
- Institute of Biology, Freie Universität Berlin, Berlin, Germany
- Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Berlin, Germany
| | - Heather G Marco
- Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa
| | - Nina Scheich
- Institute of Biology, Freie Universität Berlin, Berlin, Germany
- Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Berlin, Germany
| | - Shulin He
- College of Life Science, Chongqing Normal University, Chongqing, China
| | - Zongqing Wang
- College of Plant Protection, Southwest University, Chongqing, China
| | - Gerd Gäde
- Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa
| | - Dino P McMahon
- Institute of Biology, Freie Universität Berlin, Berlin, Germany
- Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Berlin, Germany
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6
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Esparza-Mora MA, Mazumdar T, Jiang S, Radek R, Thiem JN, Feng L, Petrašiūnaitė V, Banasiak R, Golian M, Gleske M, Lucas C, Springer A, Buellesbach J, McMahon DP. Defensive behavior is linked to altered surface chemistry following infection in a termite society. Sci Rep 2023; 13:20606. [PMID: 37996442 PMCID: PMC10667546 DOI: 10.1038/s41598-023-42947-9] [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: 05/22/2023] [Accepted: 09/16/2023] [Indexed: 11/25/2023] Open
Abstract
The care-kill response determines whether a sick individual will be treated or eliminated from an insect society, but little is known about the physiological underpinnings of this process. We exploited the stepwise infection dynamics of an entomopathogenic fungus in a termite to explore how care-kill transitions occur, and identify the chemical cues behind these shifts. We found collective responses towards pathogen-injected individuals to vary according to severity and timing of pathogen challenge, with elimination, via cannibalism, occurring sooner in response to a severe active infection. However, injection with inactivated fungal blastospores also resulted in increased albeit delayed cannibalism, even though it did not universally cause host death. This indicates that the decision to eliminate an individual is triggered before pathogen viability or terminal disease status has been established. We then compared the surface chemistry of differently challenged individuals, finding increased amounts of long-chained methyl-branched alkanes with similar branching patterns in individuals injected with both dead and viable fungal blastospores, with the latter showing the largest increase. This coincided with the highest amounts of observed cannibalism as well as signs of severe moribundity. Our study provides new mechanistic insight into the emergent collective behaviors involved in the disease defense of a termite society.
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Affiliation(s)
- M Alejandra Esparza-Mora
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195, Berlin, Germany
- Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205, Berlin, Germany
| | - Tilottama Mazumdar
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195, Berlin, Germany
- Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205, Berlin, Germany
| | - Shixiong Jiang
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195, Berlin, Germany
- Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205, Berlin, Germany
| | - Renate Radek
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195, Berlin, Germany
| | - Julian N Thiem
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195, Berlin, Germany
| | - Linshan Feng
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195, Berlin, Germany
| | - Vesta Petrašiūnaitė
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195, Berlin, Germany
| | - Ronald Banasiak
- Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205, Berlin, Germany
| | - Marek Golian
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstraße 1, 48149, Münster, Germany
| | - Melanie Gleske
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstraße 1, 48149, Münster, Germany
| | - Christophe Lucas
- Institut de Recherche sur la Biologie de l'Insecte (UMR7261), CNRS-University of Tours, Tours, France
| | - Andreas Springer
- Core Facility BioSupraMol, Department of Biology, Chemistry and Pharmacy, Freie Universität Berlin, Takustraße 3, 14195, Berlin, Germany
| | - Jan Buellesbach
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstraße 1, 48149, Münster, Germany
| | - Dino P McMahon
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195, Berlin, Germany.
- Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205, Berlin, Germany.
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Bulmer MS, Franco BA, Biswas A, Greenbaum SF. Overcoming Immune Deficiency with Allogrooming. INSECTS 2023; 14:insects14020128. [PMID: 36835697 PMCID: PMC9965724 DOI: 10.3390/insects14020128] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 05/13/2023]
Abstract
Allogrooming appears to be essential in many social animals for protection from routine exposure to parasites. In social insects, it appears to be critical for the removal of pathogenic propagules from the cuticle before they can start an infectious cycle. For subterranean termites, this includes fungal spores commonly encountered in the soil, such as Metarhizium conidia, that can quickly germinate and penetrate the cuticle. We investigated whether there is a difference in reliance on social and innate immunity in two closely related subterranean termites for protection from fatal infections by two locally encountered Metarhizium species. Our results indicate that relatively weak innate immunity in one termite species is compensated by more sustained allogrooming. This includes enhanced allogrooming in response to concentrations of conidia that reflect more routine contamination of the cuticle as well as to heavy cuticular contamination that elicits a networked emergency response.
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8
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Rosenheim JA, Schreiber SJ. Pathways to the density-dependent expression of cannibalism, and consequences for regulated population dynamics. Ecology 2022; 103:e3785. [PMID: 35818739 DOI: 10.1002/ecy.3785] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 04/13/2022] [Accepted: 04/21/2022] [Indexed: 12/13/2022]
Abstract
Cannibalism, once viewed as a rare or aberrant behavior, is now recognized to be widespread and to contribute broadly to the self-regulation of many populations. Cannibalism can produce endogenous negative feedback on population growth because it is expressed as a conditional behavior, responding to the deteriorating ecological conditions that flow, directly or indirectly, from increasing densities of conspecifics. Thus, cannibalism emerges as a strongly density-dependent source of mortality. In this synthesis, we review recent research that has revealed a rich diversity of pathways through which rising density elicits increased cannibalism, including both factors that (a) elevate the rate of dangerous encounters between conspecifics and (b) enhance the likelihood that such encounters will lead to successful cannibalistic attacks. These pathways include both features of the autecology of cannibal populations and features of interactions with other species, including food resources and pathogens. Using mathematical models, we explore the consequences of including density-dependent cannibal attack rates on population dynamics. The conditional expression of cannibalism generally enhances stability and population regulation in single-species models but also may increase opportunities for alternative states and prey population escape from control by cannibalistic predators.
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Affiliation(s)
- Jay A Rosenheim
- Department of Entomology and Nematology, University of California, Davis, California, USA
| | - Sebastian J Schreiber
- Department of Evolution and Ecology, University of California, Davis, California, USA
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9
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Zeng W, Shen D, Chen Y, Zhang S, Wu W, Li Z. A High Soldier Proportion Encouraged the Greater Antifungal Immunity in a Subterranean Termite. Front Physiol 2022; 13:906235. [PMID: 35733990 PMCID: PMC9207448 DOI: 10.3389/fphys.2022.906235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Indexed: 11/25/2022] Open
Abstract
Termites possess a mighty social immune system, serving as one of the key obstacles to controlling them biologically. However, the dynamic mechanism coordinating the social immunologic defense and caste distribution of the termites remains elusive. This study used the Coptotermes formosanus Shiraki and an entomopathogenic fungus as a host–pathogen system and experimentally manipulated a series of groups with different caste compositions of workers and soldiers. Then, the impact of demography on the behavior and innate immunity of termites was explored by analyzing the fungus susceptibility of the respective caste, efficiencies, and caste preferences of sanitary care, as well as the expression of the immune genes and phenoloxidase activity. Overall, to ensure the general health and survival of a group, the infected workers were found to sacrifice their survivorship for maintaining the soldier proportion of the group. If soldier proportion was limited within a threshold, both the survivorship of the workers and soldiers were not significantly affected by the infection. Correspondingly, the infected group with a higher proportion of soldiers stimulated the higher efficiency of a non-caste-biased sanitary care of the workers to the nestmate workers and soldiers. Moreover, the innate immunities of the infected workers were found to be more intensely upregulated in the group with higher soldier proportions. This suggested that the adjustable non-caste-biased sanitary care and innate immunity of the workers would contribute to the flexibility of the worker–soldier caste ratio in C. formosanus. This study, therefore, enhanced our understanding of the functional adaptation mechanism between pathogen-driven social immunity and the demography of the termites.
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Moran MN, Aguero CM, Eyer PA, Vargo EL. Rescue Strategy in a Termite: Workers Exposed to a Fungal Pathogen Are Reintegrated Into the Colony. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.840223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Social insect colonies are characterized by an efficient division of labor, allowing high-value individuals (i.e., reproductives and brood) to be sheltered from tasks associated with increased risk of pathogen exposure, such as foraging or corpse disposal. This social organization helps limit the transmission of disease throughout the colony. Further, individuals can actively respond to imminent disease threats by altering their behaviors as a means of social immunity. In subterranean termites, although workers typically avoid detected pathogens, they can be attracted to pathogen cues when a nestmate is infected. Infected termites are usually groomed, but they may instead be cannibalized if the infection has already become lethal. The mechanisms governing these changes in behavior are unclear. We set out to examine immediate changes in individual behaviors, investigating the role that the infected individual plays in communicating its infection status to nestmates. We also assessed gradual changes in social organization after the re-introduction of an infected termite to the colony. Our results reveal that infected termites likely do not signal their infection status to nestmates through shaking behaviors and reduced movements, suggesting the occurrence of other mechanisms used in communicating infection. We also found that infected termites do not self-isolate and may travel to the densest part of the colony, where they can potentially benefit from grooming by large groups of nestmates. These results provide new insights into how individual changes in immune behaviors contribute to overall colony health, highlighting that, at early stages of infection, termites favor a rescuing strategy rather than isolation and/or cannibalization.
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11
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Sieksmeyer T, He S, Esparza-Mora MA, Jiang S, Petrašiūnaitė V, Kuropka B, Banasiak R, Julseth MJ, Weise C, Johnston PR, Rodríguez-Rojas A, McMahon DP. Eating in a losing cause: limited benefit of modified macronutrient consumption following infection in the oriental cockroach Blatta orientalis. BMC Ecol Evol 2022; 22:67. [PMID: 35585501 PMCID: PMC9118584 DOI: 10.1186/s12862-022-02007-8] [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] [Received: 01/17/2021] [Accepted: 04/08/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Host-pathogen interactions can lead to dramatic changes in host feeding behaviour. One aspect of this includes self-medication, where infected individuals consume substances such as toxins or alter their macronutrient consumption to enhance immune competence. Another widely adopted animal response to infection is illness-induced anorexia, which is thought to assist host immunity directly or by limiting the nutritional resources available to pathogens. Here, we recorded macronutrient preferences of the global pest cockroach, Blatta orientalis to investigate how shifts in host macronutrient dietary preference and quantity of carbohydrate (C) and protein (P) interact with immunity following bacterial infection. RESULTS We find that B. orientalis avoids diets enriched for P under normal conditions, and that high P diets reduce cockroach survival in the long term. However, following bacterial challenge, cockroaches significantly reduced their overall nutrient intake, particularly of carbohydrates, and increased the relative ratio of protein (P:C) consumed. Surprisingly, these behavioural shifts had a limited effect on cockroach immunity and survival, with minor changes to immune protein abundance and antimicrobial activity between individuals placed on different diets, regardless of infection status. CONCLUSIONS We show that cockroach feeding behaviour can be modulated by a pathogen, resulting in an illness-induced anorexia-like feeding response and a shift from a C-enriched to a more P:C equal diet. However, our results also indicate that such responses do not provide significant immune protection in B. orientalis, suggesting that the host's dietary shift might also result from random rather than directed behaviour. The lack of an apparent benefit of the shift in feeding behaviour highlights a possible reduced importance of diet in immune regulation in these invasive animals, although further investigations employing pathogens with alternative infection strategies are warranted.
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Affiliation(s)
- Thorben Sieksmeyer
- Institute of Biology, Freie Universität Berlin, Schwendenerstr. 1, 14195, Berlin, Germany.,Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205, Berlin, Germany.,Department of Biotechnology, German Institute of Food Technology (DIL e.V.), Prof.-von-Klitzing-Str. 7, 49610, Quakenbrück, Germany
| | - Shulin He
- Institute of Biology, Freie Universität Berlin, Schwendenerstr. 1, 14195, Berlin, Germany.,Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205, Berlin, Germany
| | - M Alejandra Esparza-Mora
- Institute of Biology, Freie Universität Berlin, Schwendenerstr. 1, 14195, Berlin, Germany.,Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205, Berlin, Germany
| | - Shixiong Jiang
- Institute of Biology, Freie Universität Berlin, Schwendenerstr. 1, 14195, Berlin, Germany.,Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205, Berlin, Germany
| | - Vesta Petrašiūnaitė
- Institute of Biology, Freie Universität Berlin, Schwendenerstr. 1, 14195, Berlin, Germany
| | - Benno Kuropka
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany
| | - Ronald Banasiak
- Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205, Berlin, Germany
| | - Mara Jean Julseth
- Institute of Biology, Freie Universität Berlin, Schwendenerstr. 1, 14195, Berlin, Germany
| | - Christoph Weise
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany
| | - Paul R Johnston
- Institute of Biology, Freie Universität Berlin, Schwendenerstr. 1, 14195, Berlin, Germany.,Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 310, 12587, Berlin, Germany.,Berlin Center for Genomics in Biodiversity Research, Königin-Luise-Str. 6-8, 14195, Berlin, Germany
| | - Alexandro Rodríguez-Rojas
- Institute of Biology, Freie Universität Berlin, Schwendenerstr. 1, 14195, Berlin, Germany.,Internal Medicine, Vetmeduni Vienna, Veterinaerplätz 1, 1210, Vienna, Austria
| | - Dino P McMahon
- Institute of Biology, Freie Universität Berlin, Schwendenerstr. 1, 14195, Berlin, Germany. .,Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205, Berlin, Germany.
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12
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Eyer PA, Vargo EL. Short and long-term costs of inbreeding in the lifelong-partnership in a termite. Commun Biol 2022; 5:389. [PMID: 35469055 PMCID: PMC9038770 DOI: 10.1038/s42003-022-03317-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 03/24/2022] [Indexed: 11/24/2022] Open
Abstract
Social life and lifelong partner commitments are expected to favor thorough partner choice, as an ill-suited partnership may have long-term consequences, adversely affecting the parents and spanning several cohorts of offspring. Here, we used ~1400 termite incipient colonies to estimate the short- and long-term costs of inbreeding upon the survival of the parents over a 15-month period, their productivity, and the resistance of their offspring toward pathogen pressure. We observed that foundation success was not influenced by the relatedness of partners, but by their levels of microbial load. We showed faster growth in inbred colonies with low levels of microbial load, revealing a potential tradeoff between pathogen defense and offspring production. Yet, inbreeding takes its toll later in colony development when offspring from incipient colonies face pathogen pressure. Although the success of a lifetime partnership is initially determined by the partner’s health, the cost of inbreeding in incipient colonies favors outbred colonies reaching maturity. Studies of termite colonies over 15 months show that inbred colonies exhibit faster initial growth with low levels of microbial load, but higher mortality toward pathogens later in colony development.
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Affiliation(s)
- Pierre-André Eyer
- Department of Entomology, 2143 TAMU, Texas A&M University, College Station, TX, 77843-2143, USA.
| | - Edward L Vargo
- Department of Entomology, 2143 TAMU, Texas A&M University, College Station, TX, 77843-2143, USA
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Dead Brood of Apis mellifera Is Removed More Effectively from Small-Cell Combs Than from Standard-Cell Combs. Animals (Basel) 2022; 12:ani12040418. [PMID: 35203126 PMCID: PMC8868292 DOI: 10.3390/ani12040418] [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: 01/10/2022] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 11/20/2022] Open
Abstract
Simple Summary Honeybee workers are able to detect dead or infected brood in comb cells and remove it outside the nest before the infection spreads onto the colony. Such a phenomena is called an hygienic behaviour. Colonies with efficient hygienic behaviour are more resistant to diseases. Bee comb cells may vary in width. In Europe, standard-cell combs (cell width approx. 5.50 mm) and small-cell combs (cell width approx. 4.90 mm) are used. Typically, colonies are kept only on standard- or small-cell combs. We assessed the dead brood removal efficiency in colonies kept on both comb types. Simultaneous keeping of a colony on standard- and small-cell combs is a novel approach to the use of small-cell combs in beekeeping. The removal from small-cell combs was significantly more efficient than in the case of the standard-cell combs, which indicates that bees find dead brood in small-cell combs faster or devoted more attention to the removal. Better understanding of the effect of the simultaneous keeping of colonies on standard- and small-cell combs on the efficiency of hygienic behaviour may contribute to enhancement of the resistance of bee colonies to diseases. Abstract The efficiency of the hygienic behaviour in bee colonies towards dead brood was assessed in small-cell combs (SMCombs) and in standard-cell combs (STCombs). Each colony had both types of combs in the nest on a permanent basis. Simultaneous keeping of a colony on standard- and small-cell combs is a novel approach to the use of small-cell combs in beekeeping. The number of killed pupae removed within 24 h was the measure of the hygienic behaviour efficiency. Regardless of the year, the brood in the SMCombs was uncapped and removed significantly more efficient (p ≤ 0.01) than in the STCombs (number of non-uncapped cells: in 2020 SMCombs = 3.79, STCombs = 11.62; in 2021 SMCombs = 2.34, STCombs = 5.28 and completely removed cells: in 2020 SMCombs = 87.46, STCombs = 80.04; in 2021 SMCombs = 96.75, STCombs = 92.66). In colonies kept simultaneously on standard- and small-cell combs, the width of the comb cells has a significant effect on the efficiency of removal of dead brood, which is removed more efficient from small-cell combs than from standard-cell combs.
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Wu CY, Meng J, Merchant A, Zhang YX, Li MW, Zhou XG, Wang Q. Microbial Response to Fungal Infection in a Fungus-Growing Termite, Odontotermes formosanus (Shiraki). Front Microbiol 2021; 12:723508. [PMID: 34880836 PMCID: PMC8645866 DOI: 10.3389/fmicb.2021.723508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 11/01/2021] [Indexed: 12/12/2022] Open
Abstract
The crosstalk between gut microbiota and host immunity has emerged as one of the research foci of microbiome studies in recent years. The purpose of this study was to determine how gut microbes respond to fungal infection in termites, given their reliance on gut symbionts for food intake as well as maintaining host health. Here, we used Metarhizium robertsii, an entomopathogenic fungus, to infect Odontotermes formosanus, a fungus-growing termite in the family Termitidae, and documented changes in host gut microbiota via a combination of bacterial 16S rDNA sequencing, metagenomic shotgun sequencing, and transmission electron microscopy. Our analyses found that when challenged with Metarhizium, the termite gut showed reduced microbial diversity within the first 12 h of fungal infection and then recovered and even surpassed pre-infection flora levels. These combined results shed light on the role of gut flora in maintaining homeostasis and immune homeostasis in the host, and the impact of gut flora dysbiosis on host susceptibility to infection.
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Affiliation(s)
- Chen-Yu Wu
- Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China.,School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Jing Meng
- Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China
| | - Austin Merchant
- Department of Entomology, University of Kentucky, Lexington, KY, United States
| | - Yi-Xiang Zhang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Mu-Wang Li
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Xu-Guo Zhou
- Department of Entomology, University of Kentucky, Lexington, KY, United States
| | - Qian Wang
- Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China
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15
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Alciatore G, Ugelvig LV, Frank E, Bidaux J, Gal A, Schmitt T, Kronauer DJC, Ulrich Y. Immune challenges increase network centrality in a queenless ant. Proc Biol Sci 2021; 288:20211456. [PMID: 34493081 PMCID: PMC8424377 DOI: 10.1098/rspb.2021.1456] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 08/13/2021] [Indexed: 11/12/2022] Open
Abstract
Social animals display a wide range of behavioural defences against infectious diseases, some of which increase social contacts with infectious individuals (e.g. mutual grooming), while others decrease them (e.g. social exclusion). These defences often rely on the detection of infectious individuals, but this can be achieved in several ways that are difficult to differentiate. Here, we combine non-pathogenic immune challenges with automated tracking in colonies of the clonal raider ant to ask whether ants can detect the immune status of their social partners and to quantify their behavioural responses to this perceived infection risk. We first show that a key behavioural response elicited by live pathogens (allogrooming) can be qualitatively recapitulated by immune challenges alone. Automated scoring of interactions between all colony members reveals that this behavioural response increases the network centrality of immune-challenged individuals through a general increase in physical contacts. These results show that ants can detect the immune status of their nest-mates and respond with a general 'caring' strategy, rather than avoidance, towards social partners that are perceived to be infectious. Finally, we find no evidence that changes in cuticular hydrocarbon profiles drive these behavioural effects.
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Affiliation(s)
- Giacomo Alciatore
- Institute of Integrative Biology, ETHZ Zürich, 8092 Zürich, Switzerland
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
| | - Line V. Ugelvig
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY 10065, USA
- Centre for Social Evolution, University of Copenhagen, 2100 Copenhagen N, Denmark
| | - Erik Frank
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
- Department of Animal Ecology and Tropical Biology, University of Würzburg, Biocentre, 97074 Würzburg, Germany
| | - Jérémie Bidaux
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
| | - Asaf Gal
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY 10065, USA
| | - Thomas Schmitt
- Department of Animal Ecology and Tropical Biology, University of Würzburg, Biocentre, 97074 Würzburg, Germany
| | - Daniel J. C. Kronauer
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY 10065, USA
| | - Yuko Ulrich
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
- Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany
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16
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Hassan A, Huang Q, Mehmood N, Xu H, Zhou W, Gao Y. Alteration of Termite Locomotion and Allogrooming in Response to Infection by Pathogenic Fungi. JOURNAL OF ECONOMIC ENTOMOLOGY 2021; 114:1256-1263. [PMID: 33909076 DOI: 10.1093/jee/toab071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Indexed: 06/12/2023]
Abstract
Termites, being vulnerable to parasitic or pathogenic infections due to large number of individuals living together in colonies, have evolved various behavioral and physiological tactics to resist the infections by those pathogens. Locomotion can help termites collect information on parasites and accordingly exhibit hygienic behaviors. Termites inevitably encounter entomopathogenic fungi during nesting and foraging. However, how these fungal pathogens influence locomotion of termites and how hygienic behavior benefits their survival remains unknown. Here, we examined locomotion alteration of the termite Reticulitermes chinensis (Isoptera: Rhinotermitidae) after infections with different concentrations of the entomopathogenic fungus Metarhizium anisopliae (Hypocreales: Clavicipitaceae). When R. chinensis was isolated, the low concentration (5 × 103 conidia/ml) significantly increased termite locomotion after 6, 12, and 24 h compared with control. However, the high concentrations (5 × 107, 5 × 109 conidia/ml) significantly decreased termite locomotion after 48 h, and termite survival was also significantly lower at 5 × 107 and 5 × 109 conidia/ml compared with the low concentrations and the control. When R. chinensis was in group, however, the locomotion significantly increased 24 h after exposure to 5 × 103 and 5 × 109 conidia/ml but was normalized after 48 h of exposure compared with the control. Allogrooming was significantly higher at 5 × 103 and 5 × 109 conidia/ml compared with the control. The fungal infection did not result in significantly higher mortality of the group termites probably owing to their allogrooming. These findings enhance our understanding on how a termite species copes with biotic stress (i.e., fungal infections) via adaptive behaviors.
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Affiliation(s)
- Ali Hassan
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, China
| | - Qiuying Huang
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, China
| | - Nasir Mehmood
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, China
| | - Huan Xu
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, China
| | - Wei Zhou
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, China
| | - Yongyong Gao
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, China
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Aguero CM, Eyer P, Martin JS, Bulmer MS, Vargo EL. Natural variation in colony inbreeding does not influence susceptibility to a fungal pathogen in a termite. Ecol Evol 2021; 11:3072-3083. [PMID: 33841768 PMCID: PMC8019025 DOI: 10.1002/ece3.7233] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 01/08/2021] [Accepted: 01/15/2021] [Indexed: 01/26/2023] Open
Abstract
Reduced genetic diversity through inbreeding can negatively affect pathogen resistance. This relationship becomes more complicated in social species, such as social insects, since the chance of disease transmission increases with the frequency of interactions among individuals. However, social insects may benefit from social immunity, whereby individual physiological defenses may be bolstered by collective-level immune responses, such as grooming or sharing of antimicrobial substance through trophallaxis. We set out to determine whether differences in genetic diversity between colonies of the subterranean termite, Reticulitermes flavipes, accounts for colony survival against pathogens. We sampled colonies throughout the United States (Texas, North Carolina, Maryland, and Massachusetts) and determined the level of inbreeding of each colony. To assess whether genetically diverse colonies were better able to survive exposure to diverse pathogens, we challenged groups of termite workers with two strains of a pathogenic fungus, one local strain present in the soil surrounding sampled colonies and another naïve strain, collected outside the range of this species. We found natural variation in the level of inbreeding between colonies, but this variation did not explain differences in susceptibility to either pathogen. Although the naïve strain was found to be more hazardous than the local strain, colony resistance was correlated between two strains, meaning that colonies had either relatively high or low susceptibility to both strains regardless of their inbreeding coefficient. Overall, our findings may reflect differential virulence between the strains, immune priming of the colonies via prior exposure to the local strain, or a coevolved resistance toward this strain. They also suggest that colony survival may rely more upon additional factors, such as different behavioral response thresholds or the influence of a specific genetic background, rather than the overall genetic diversity of the colony.
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Affiliation(s)
- Carlos M. Aguero
- Department of EntomologyTexas A&M UniversityCollege StationTXUSA
| | | | - Jason S. Martin
- Department of Biological SciencesTowson UniversityTowsonMDUSA
| | - Mark S. Bulmer
- Department of Biological SciencesTowson UniversityTowsonMDUSA
| | - Edward L. Vargo
- Department of EntomologyTexas A&M UniversityCollege StationTXUSA
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18
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Interaction between Metarhizium anisopliae and Its Host, the Subterranean Termite Coptotermes curvignathus during the Infection Process. BIOLOGY 2021; 10:biology10040263. [PMID: 33806225 PMCID: PMC8065498 DOI: 10.3390/biology10040263] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 01/11/2021] [Accepted: 01/20/2021] [Indexed: 11/17/2022]
Abstract
Metarhizium anisopliae (Metchnikoff) Sorokin, a pathogenic fungus to insects, infects the subterranean termite, Coptotermes curvignathus Holmgren, a devastating pest of plantation trees in the tropics. Electron microscopy and proteomics were used to investigate the infection and developmental process of M. anisopliae in C. curvignathus. Fungal infection was initiated by germ tube penetration through the host's cuticle as observed at 6 h post-inoculation (PI), after which it elongated into the host's integumental tissue. The colonization process continued as seen from dissemination of blastospores in the hemocoel at 96 h PI. At this time point, the emergent mycelia had mummified the host and forty-eight hours later, new conidia were dispersed on the termites' body surface. Meanwhile, hyphal bodies were observed in abundance in the intercellular space in the host's body. The proteomes of the pathogen and host were isolated separately using inoculated termite samples withdrawn at each PI-time point and analyzed in two-dimensional electrophoresis (2-DE) gels. Proteins expressed in termites showed evidence of being related to cell regulation and the immune response, while those expressed in M. anisopliae, to transportation and fungal virulence. This study provides new information on the interaction between termites and its entomopathogen, with potential utilization for developing future biopesticide to control the termite population.
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19
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Oberpaul M, Zumkeller CM, Culver T, Spohn M, Mihajlovic S, Leis B, Glaeser SP, Plarre R, McMahon DP, Hammann P, Schäberle TF, Glaeser J, Vilcinskas A. High-Throughput Cultivation for the Selective Isolation of Acidobacteria From Termite Nests. Front Microbiol 2020; 11:597628. [PMID: 33240253 PMCID: PMC7677567 DOI: 10.3389/fmicb.2020.597628] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 10/19/2020] [Indexed: 12/27/2022] Open
Abstract
Microbial communities in the immediate environment of socialized invertebrates can help to suppress pathogens, in part by synthesizing bioactive natural products. Here we characterized the core microbiomes of three termite species (genus Coptotermes) and their nest material to gain more insight into the diversity of termite-associated bacteria. Sampling a healthy termite colony over time implicated a consolidated and highly stable microbiome, pointing toward the fact that beneficial bacterial phyla play a major role in termite fitness. In contrast, there was a significant shift in the composition of the core microbiome in one nest during a fungal infection, affecting the abundance of well-characterized Streptomyces species (phylum Actinobacteria) as well as less-studied bacterial phyla such as Acidobacteria. High-throughput cultivation in microplates was implemented to isolate and identify these less-studied bacterial phylogenetic group. Amplicon sequencing confirmed that our method maintained the bacterial diversity of the environmental samples, enabling the isolation of novel Acidobacteriaceae and expanding the list of cultivated species to include two strains that may define new species within the genera Terracidiphilus and Acidobacterium.
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Affiliation(s)
- Markus Oberpaul
- Branch for Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Giessen, Germany
| | - Celine M. Zumkeller
- Branch for Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Giessen, Germany
| | - Tanja Culver
- Branch for Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Giessen, Germany
| | - Marius Spohn
- Branch for Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Giessen, Germany
| | - Sanja Mihajlovic
- Branch for Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Giessen, Germany
| | - Benedikt Leis
- Branch for Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Giessen, Germany
| | - Stefanie P. Glaeser
- Institute of Applied Microbiology, Justus Liebig University Giessen, Giessen, Germany
| | - Rudy Plarre
- Bundesanstalt für Materialforschung und -prüfung, Berlin, Germany
| | - Dino P. McMahon
- Bundesanstalt für Materialforschung und -prüfung, Berlin, Germany
- Institute of Biology, Free University of Berlin, Berlin, Germany
| | - Peter Hammann
- Sanofi-Aventis Deutschland GmbH, R&D Integrated Drug Discovery, Hoechst Industrial Park, Frankfurt am Main, Germany
| | - Till F. Schäberle
- Branch for Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Giessen, Germany
- Institute for Insect Biotechnology, Justus Liebig University Giessen, Giessen, Germany
| | - Jens Glaeser
- Branch for Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Giessen, Germany
| | - Andreas Vilcinskas
- Branch for Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Giessen, Germany
- Institute for Insect Biotechnology, Justus Liebig University Giessen, Giessen, Germany
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20
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Maák I, Tóth E, Lenda M, Lőrinczi G, Kiss A, Juhász O, Czechowski W, Torma A. Behaviours indicating cannibalistic necrophagy in ants are modulated by the perception of pathogen infection level. Sci Rep 2020; 10:17906. [PMID: 33087857 PMCID: PMC7578781 DOI: 10.1038/s41598-020-74870-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 09/21/2020] [Indexed: 12/25/2022] Open
Abstract
Cannibalistic necrophagy is rarely observed in social hymenopterans, although a lack of food could easily favour such behaviour. One of the main supposed reasons for the rarity of necrophagy is that eating of nestmate corpses carries the risk of rapid spread of pathogens or parasites. Here we present an experimental laboratory study on behaviour indicating consumption of nestmate corpses in the ant Formica polyctena. We examined whether starvation and the fungal infection level of the corpses affects the occurrence of cannibalistic necrophagy. Our results showed that the ants distinguished between corpses of different types and with different levels of infection risk, adjusting their behaviour accordingly. The frequency of behaviours indicating cannibalistic necrophagy increased during starvation, although these behaviours seem to be fairly common in F. polyctena even in the presence of other food sources. The occurrence and significance of cannibalistic necrophagy deserve further research because, in addition to providing additional food, it may be part of the hygienic behaviour repertoire. The ability to detect infections and handle pathogens are important behavioural adaptations for social insects, crucial for the fitness of both individual workers and the entire colony.
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Affiliation(s)
- István Maák
- Museum and Institute of Zoology, Polish Academy of Sciences, Wilcza 64, 00-679, Warsaw, Poland.
- Department of Ecology, University of Szeged, Közép Fasor 52, Szeged, 6726, Hungary.
| | - Eszter Tóth
- Department of Microbiology, University of Szeged, Közép Fasor 52, Szeged, 6726, Hungary
- Fungal Pathogenicity Mechanisms Research Group, Hungarian Academy of Sciences, University of Szeged, Közép Fasor 52, Szeged, 6726, Hungary
| | - Magdalena Lenda
- Australian Research Council Centre of Excellence for Environmental Decisions, School of Biological Sciences, University of Queensland, St. Lucia, QLD, 4072, Australia
- Institute of Nature Conservation, Polish Academy of Sciences, Mickiewicza 33, 31-120, Kraków, Poland
| | - Gábor Lőrinczi
- Department of Ecology, University of Szeged, Közép Fasor 52, Szeged, 6726, Hungary
| | - Anett Kiss
- Department of Ecology, University of Szeged, Közép Fasor 52, Szeged, 6726, Hungary
| | - Orsolya Juhász
- Department of Ecology, University of Szeged, Közép Fasor 52, Szeged, 6726, Hungary
- Doctoral School in Biology, Faculty of Science and Informatics, University of Szeged, Közép Fasor 52, Szeged, 6726, Hungary
| | - Wojciech Czechowski
- Museum and Institute of Zoology, Polish Academy of Sciences, Wilcza 64, 00-679, Warsaw, Poland
| | - Attila Torma
- Department of Ecology, University of Szeged, Közép Fasor 52, Szeged, 6726, Hungary
- Center for Ecological Research, Institute of Ecology and Botany, 'Lendület' Landscape and Conservation Ecology, Alkotmány Utca 2-4, Vácrátót, 2163, Hungary
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21
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22
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Zhao X, Liu L, Zhou W, Cai Q, Huang Q. Roles of selenoprotein T and transglutaminase in active immunization against entomopathogenic fungi in the termite Reticulitermes chinensis. JOURNAL OF INSECT PHYSIOLOGY 2020; 125:104085. [PMID: 32634432 DOI: 10.1016/j.jinsphys.2020.104085] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 06/11/2023]
Abstract
Active immunization can protect individuals from infectious diseases in social insects. It is well established that trace elements are essential to the host immune system, but the related gene functions in insect social immunity are unknown. Here, we found that the levels of three free elements (Se, Ca and Cr) and selenoprotein T (SELT) expression were significantly decreased in the termite Reticulitermes chinensis Snyder during active immunization against the entomopathogenic fungus Metarhizium anisopliae (Metchnikoff) Sorokin. Thus, we further explored the role of the SELT gene in the active immunization of termites. After SELT was significantly silenced by RNAi, the nestmates of fungus-contaminated termites exhibited reduced antifungal activity and increased mortality, along with increased expression of the immune genes transglutaminase (TG) and transferrin (Tsf), indicating that the active immunization of termites was disrupted by SELT silencing. Moreover, the TG-knockdown nestmates of fungus-contaminated termites significantly decreased grooming behavior, antifungal activity and survival, despite the upregulation of SELT expression, also suggesting that the active immunization of termites was disrupted by the silencing of TG. These findings demonstrated that both SELT gene and TG gene play important roles in driving active immunization against the entomopathogenic fungus M. anisopliae in R. chinensis.
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Affiliation(s)
- Xingying Zhao
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Long Liu
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Wei Zhou
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Qing Cai
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Qiuying Huang
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, Hubei, China.
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Pereira H, Detrain C. Prophylactic Avoidance of Hazardous Prey by the Ant Host Myrmica rubra. INSECTS 2020; 11:E444. [PMID: 32674516 PMCID: PMC7412340 DOI: 10.3390/insects11070444] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/03/2020] [Accepted: 07/10/2020] [Indexed: 12/13/2022]
Abstract
Ants are the hosts of many microorganisms, including pathogens that are incidentally brought inside the nest by foragers. This is particularly true for scavenging species, which collect hazardous food such as dead insects. Foragers limit sanitary risks by not retrieving highly infectious prey releasing entomopathogenic fungal spores. This study investigates whether similar prophylactic strategies are also developed for food associated with weak or delayed risks of fungal contamination. We compared, in Myrmica rubra ant colonies, the retrieval dynamics of dead flies that were (1) conidia-free, (2) covered with a low amount of Metarhizium brunneum entomopathogenic conidia or (3) recently fungus-killed but not yet sporulating. Foragers mostly avoided fungus-killed prey and delayed the retrieval of conidia-covered flies. A second sanitary filter occurred inside the nest through a careful inspection of the retrieved prey. Ultimately, ants mostly consumed conidia-free and conidia-covered flies, but they relocated and discarded all fungus-killed prey outside of the nest. Our study confirms that, as a host of generalist entomopathogenic fungi, Myrmica rubra ants have developed a prophylactic avoidance and a differential management of prey depending on their infectious potential. We discuss the functional value as well as the possible cues underlying pathogen avoidance and prey discrimination in ants.
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Affiliation(s)
- Hugo Pereira
- Unit of Social Ecology, CP 231, Université Libre de Bruxelles, Boulevard du Triomphe, 1050 Brussels, Belgium;
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Pull CD, McMahon DP. Superorganism Immunity: A Major Transition in Immune System Evolution. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00186] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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25
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Wen C, Xiong H, Wen J, Wen X, Wang C. Trichoderma Species Attract Coptotermes formosanus and Antagonize Termite Pathogen Metarhizium anisopliae. Front Microbiol 2020; 11:653. [PMID: 32328057 PMCID: PMC7160823 DOI: 10.3389/fmicb.2020.00653] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/23/2020] [Indexed: 11/25/2022] Open
Abstract
Although subterranean termites live within soil, little attention has been paid on the potential interaction among subterranean termites and soil microbes. Herein, we conducted different choice tests to investigate aggregation and tunneling behaviors of Coptotermes formosanus Shiraki responding to soil/sand treated with conidia of seven soil fungi, Trichoderma longibrachiatum Rifai, Trichoderma koningii Oud., Trichoderma hamatum (Bon.) Bain., Trichoderma atroviride Karsten, Trichoderma spirale Indira and Kamala, Trichoderma harzianum Rifai, and Trichoderma viride Pers. ex Fries. In aggregation-choice test, soil treated with nearly all Trichoderma species tested (except T. koningii) significantly increased termite aggregation compared with untreated soil. In tunneling-choice tests, termites produced significantly larger tunnels in sand treated with T. longibrachiatum or T. koningii than that in untreated sand. We hypothesized that Trichoderma species could benefit termites by protecting them from infection of the entomopathogenic fungus Metarhizium anisopliae (Metschn) Sorokin, and three Trichoderma species that attracted termites (T. longibrachiatum, T. atroviride, and T. harzianum) were tested. The antagonism tests showed that the three Trichoderma species suppressed growth of M. anisopliae. Also, the median lethal time (LT50) of termites exposed to both Trichoderma species and M. anisopliae was significantly longer than termites exposed to M. anisopliae alone. Interestingly, though significantly fewer termites aggregated in soil treated with M. anisopliae conidia compared with untreated soil, M. anisopliae conidia mixed with T. longibrachiatum or T. harzianum were no longer repellent to termites. Our results showed that the fungi in the genus Trichoderma (1) exerted generally attractive effects on termites, (2) protected termites from the infection of entomopathogenic fungus, and (3) altered pathogen-avoiding behaviors of termites. Future studies will be required to understand the mechanisms underlying these newly discovered effects.
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Affiliation(s)
- Chao Wen
- Guangdong Key Laboratory for Innovation Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China.,Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Hongpeng Xiong
- Guangdong Key Laboratory for Innovation Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Junbao Wen
- Beijing Key Laboratory for Forest Pest Control, College of Forestry, Beijing Forestry University, Beijing, China
| | - Xiujun Wen
- Guangdong Key Laboratory for Innovation Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Cai Wang
- Guangdong Key Laboratory for Innovation Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
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26
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Evaluation of direct and indirect transmission of fungal spores in ants. J Invertebr Pathol 2020; 172:107351. [PMID: 32171803 DOI: 10.1016/j.jip.2020.107351] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 02/17/2020] [Accepted: 02/26/2020] [Indexed: 01/17/2023]
Abstract
Parasite transmission plays a central role in disease dynamics, but little is known about the extent to which direct and indirect transmission contributes to disease dynamics in group-living animals. Quantifying transmission by contact or exposure is challenging, as direct measurements of pathogen transmission are often impractical and individual behaviour is largely unknown. Here, we attempt to tackle these twin problems through the use of a generalist entomopathogenic fungus Metarhizium robertsii to study direct and indirect transmission in the black carpenter ant Camponotus pennsylvanicus. We provide evidence that large quantities of fungal conidia (spores) can be acquired over time on the ant's cuticle and significant amounts are shed into the environment, allowing indirect transmission. Unexposed ants in the nest can be infected either through direct (i.e. social contacts) or indirect (i.e. acquisition from the environment) transmission, potentially leading to the same mortality as if all individuals of a nest would have been directly exposed to the pathogen. Our findings highlight the importance of indirect transmission routes in a species of social living organisms.
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Aguero CM, Eyer PA, Vargo EL. Increased genetic diversity from colony merging in termites does not improve survival against a fungal pathogen. Sci Rep 2020; 10:4212. [PMID: 32144325 PMCID: PMC7060273 DOI: 10.1038/s41598-020-61278-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 02/24/2020] [Indexed: 12/26/2022] Open
Abstract
In some species of social insects the increased genetic diversity from having multiple breeders in a colony has been shown to improve pathogen resistance. Termite species typically found colonies from single mated pairs and therefore may lack the flexibility to buffer pathogen pressure with increased genetic diversity by varying the initial number of reproductives. However, they can later increase group diversity through colony merging, resulting in a genetically diverse, yet cohesive, workforce. In this study, we investigate whether the increased group diversity from colony fusion benefits social immunity in the subterranean termite Reticulitermes flavipes. We confirm previous findings that colonies of R. flavipes will readily merge and we show that workers will equally groom nestmates and non-nestmates after merging. Despite this, the survival of these merged colonies was not improved after exposure to a fungal pathogen, but instead leveled to that of the more susceptible or the more resistant colony. Our study brings little support to the hypothesis that colony fusion may improve immunity through an increase of genetic diversity in R. flavipes. Instead, we find that following exposure to a lethal pathogen, one colony is heavily influential to the entire group's survival after merging.
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Affiliation(s)
- Carlos M Aguero
- Department of Entomology, 2143 TAMU, Texas A&M University, College Station, Texas, 77843-2143, USA.
| | - Pierre-André Eyer
- Department of Entomology, 2143 TAMU, Texas A&M University, College Station, Texas, 77843-2143, USA
| | - Edward L Vargo
- Department of Entomology, 2143 TAMU, Texas A&M University, College Station, Texas, 77843-2143, USA
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28
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Milutinović B, Stock M, Grasse AV, Naderlinger E, Hilbe C, Cremer S. Social immunity modulates competition between coinfecting pathogens. Ecol Lett 2020; 23:565-574. [PMID: 31950595 DOI: 10.1111/ele.13458] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/31/2019] [Accepted: 12/14/2019] [Indexed: 12/18/2022]
Abstract
Coinfections with multiple pathogens can result in complex within-host dynamics affecting virulence and transmission. While multiple infections are intensively studied in solitary hosts, it is so far unresolved how social host interactions interfere with pathogen competition, and if this depends on coinfection diversity. We studied how the collective disease defences of ants - their social immunity - influence pathogen competition in coinfections of same or different fungal pathogen species. Social immunity reduced virulence for all pathogen combinations, but interfered with spore production only in different-species coinfections. Here, it decreased overall pathogen sporulation success while increasing co-sporulation on individual cadavers and maintaining a higher pathogen diversity at the community level. Mathematical modelling revealed that host sanitary care alone can modulate competitive outcomes between pathogens, giving advantage to fast-germinating, thus less grooming-sensitive ones. Host social interactions can hence modulate infection dynamics in coinfected group members, thereby altering pathogen communities at the host level and population level.
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Affiliation(s)
- Barbara Milutinović
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400, Klosterneuburg, Austria
| | - Miriam Stock
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400, Klosterneuburg, Austria
| | - Anna V Grasse
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400, Klosterneuburg, Austria
| | - Elisabeth Naderlinger
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400, Klosterneuburg, Austria
| | - Christian Hilbe
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400, Klosterneuburg, Austria
| | - Sylvia Cremer
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400, Klosterneuburg, Austria
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29
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da Silva LHB, Haifig I, Costa-Leonardo AM. Facing death: How does the subterranean termite Coptotermes gestroi (Isoptera: Rhinotermitidae) deal with corpses? ZOOLOGY 2019; 137:125712. [DOI: 10.1016/j.zool.2019.125712] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 09/30/2019] [Accepted: 10/02/2019] [Indexed: 01/10/2023]
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30
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The Effects of Trichoderma Fungi on the Tunneling, Aggregation, and Colony-Initiation Preferences of Black-Winged Subterranean Termites, Odontotermes formosanus (Blattodea: Termitidae). FORESTS 2019. [DOI: 10.3390/f10111020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The black-winged subterranean termite, Odontotermes formosanus Shiraki, is a severe pest of plantations and forests in China. This termite cultures symbiotic Termitomyces in the fungal combs, which are challenged by antagonistic microbes such as Trichoderma fungi. In a previous study we showed that O. formosanus workers made significantly fewer tunnels in sand containing commercially formulated conidia of Trichoderma viride Pers. ex Fries compared with untreated sand. Herein, we hypothesize that fungi in the genus Trichoderma exert repellent effects on O. formosanus. Different choice tests were conducted to evaluate the tunneling and aggregation behaviors of O. formosanus workers reacting to sand/soil containing the unformulated conidia of seven Trichoderma fungi (Trichoderma longibrachiatum Rifai, Trichoderma koningii Oud., Trichoderma harzianum Rifai, Trichoderma hamatum (Bon.) Bain, Trichoderma atroviride Karsten, Trichoderma spirale Indira and Kamala, and T. viride). We also investigated the colony-initiation preference of paired O. formosanus adults to soil treated with Trichoderma conidia (T. koningii or T. longibrachiatum) versus untreated soil. Tunneling-choice tests showed that sand containing conidia of nearly all Trichoderma fungi tested (except T. harzianum) significantly decreased tunneling activity in O. formosanus workers compared with untreated sand. Aggregation-choice test showed that T. koningii, T. atroviride and T. spirale repelled O. formosanus workers, whereas T. longibrachiatum and T. hamatum attracted termites. There was no significant difference in proportions of paired adults that stayed and laid eggs in the soil blocks treated with conidia of Trichoderma fungi and untreated ones. Our study showed that Trichoderma fungi generally repelled tunneling in O. formosanus, but may exert varied effects on aggregation preference by workers.
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31
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Subterranean Termite Social Alarm and Hygienic Responses to Fungal Pathogens. INSECTS 2019; 10:insects10080240. [PMID: 31387197 PMCID: PMC6723859 DOI: 10.3390/insects10080240] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 08/01/2019] [Accepted: 08/02/2019] [Indexed: 11/17/2022]
Abstract
In social insects, alerting nestmates to the presence of a pathogen should be critical for limiting its spread and initiating social mechanisms of defense. Here we show that subterranean termites use elevated vibratory alarm behavior to help prevent fatal fungal infections. The elevated alarm leads to elevated social hygiene. This requires that termites coalesce so that they can groom each other’s cuticular surfaces of contaminating conidial spores. Groups of 12 Reticulitermes flavipes workers varied in their response when immersed in conidia solutions of nine different strains of Metarhizium. Pathogen alarm displays of short 2–7-second bursts of rapid longitudinal oscillatory movement (LOM), observed over 12 min following a fungal challenge, were positively correlated with the time that workers spent aggregated together grooming each other. The frequency of these LOMs was inversely correlated with fatal fungal infections. The variation in fatalities appeared to be largely attributable to a differential response to Metarhizium brunneum and Metarhizium robertsii in the time spent in aggregations and the frequency of allogrooming. Isolated workers challenged with conidia did not display LOMs, which suggests that the alarm is a conditional social response. LOMs appear to help signal the presence of fungal pathogens whose virulence depends on the level of this emergency alert.
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32
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Hall MD, Routtu J, Ebert D. Dissecting the genetic architecture of a stepwise infection process. Mol Ecol 2019; 28:3942-3957. [PMID: 31283079 DOI: 10.1111/mec.15166] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 06/27/2019] [Accepted: 06/28/2019] [Indexed: 02/06/2023]
Abstract
How a host fights infection depends on an ordered sequence of steps, beginning with attempts to prevent a pathogen from establishing an infection, through to steps that mitigate a pathogen's control of host resources or minimize the damage caused during infection. Yet empirically characterizing the genetic basis of these steps remains challenging. Although each step is likely to have a unique genetic and environmental signature, and may therefore respond to selection in different ways, events that occur earlier in the infection process can mask or overwhelm the contributions of subsequent steps. In this study, we dissect the genetic architecture of a stepwise infection process using a quantitative trait locus (QTL) mapping approach. We control for variation at the first line of defence against a bacterial pathogen and expose downstream genetic variability related to the host's ability to mitigate the damage pathogens cause. In our model, the water-flea Daphnia magna, we found a single major effect QTL, explaining 64% of the variance, that is linked to the host's ability to completely block pathogen entry by preventing their attachment to the host oesophagus; this is consistent with the detection of this locus in previous studies. In susceptible hosts allowing attachment, however, a further 23 QTLs, explaining between 5% and 16% of the variance, were mapped to traits related to the expression of disease. The general lack of pleiotropy and epistasis for traits related to the different stages of the infection process, together with the wide distribution of QTLs across the genome, highlights the modular nature of a host's defence portfolio, and the potential for each different step to evolve independently. We discuss how isolating the genetic basis of individual steps can help to resolve discussion over the genetic architecture of host resistance.
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Affiliation(s)
- Matthew D Hall
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland.,School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Jarkko Routtu
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland.,Molecular Ecology, Martin-Luther-Universität, Halle-Wittenberg, Germany
| | - Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
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33
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Bonadies E, Wcislo WT, Gálvez D, Hughes WOH, Fernández-Marín H. Hygiene Defense Behaviors Used by a Fungus-Growing Ant Depend on the Fungal Pathogen Stages. INSECTS 2019; 10:insects10050130. [PMID: 31060310 PMCID: PMC6572560 DOI: 10.3390/insects10050130] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/09/2019] [Accepted: 04/11/2019] [Indexed: 11/24/2022]
Abstract
Parasites and their hosts use different strategies to overcome the defenses of the other, often resulting in an evolutionary arms race. Limited animal studies have explored the differential responses of hosts when challenged by differential parasite loads and different developmental stages of a parasite. The fungus-growing ant Trachymyrmex sp. 10 employs three different hygienic strategies to control fungal pathogens: Grooming the antibiotic-producing metapleural glands (MGs) and planting or weeding their mutualistic fungal crop. By inoculating Trachymyrmex colonies with different parasite concentrations (Metarhizium) or stages (germinated conidia or ungermianted conidia of Metarhizium and Escovopsis), we tested whether ants modulate and change hygienic strategies depending on the nature of the parasite challenge. There was no effect of the concentration of parasite on the frequencies of the defensive behaviors, indicating that the ants did not change defensive strategy according to the level of threat. However, when challenged with conidia of Escovopsis sp. and Metarhizium brunneum that were germinated or not-germinated, the ants adjusted their thygienic behavior to fungal planting and MG grooming behaviors using strategies depending on the conidia germination status. Our study suggests that fungus-growing ants can adjust the use of hygienic strategies based on the nature of the parasites.
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Affiliation(s)
- Ernesto Bonadies
- Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Apartado 0843-01103, Panamá, República de Panamá.
- Programa de Maestría en Entomología, Vicerrectoría de Investigación y Postgrado, Estafeta Universitaria 0824, Universidad de Panamá, República de Panamá.
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panamá, República de Panamá.
| | - William T Wcislo
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panamá, República de Panamá.
| | - Dumas Gálvez
- Programa de Maestría en Entomología, Vicerrectoría de Investigación y Postgrado, Estafeta Universitaria 0824, Universidad de Panamá, República de Panamá.
| | | | - Hermógenes Fernández-Marín
- Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Apartado 0843-01103, Panamá, República de Panamá.
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34
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Liu L, Zhao XY, Tang QB, Lei CL, Huang QY. The Mechanisms of Social Immunity Against Fungal Infections in Eusocial Insects. Toxins (Basel) 2019; 11:E244. [PMID: 31035652 PMCID: PMC6563085 DOI: 10.3390/toxins11050244] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 04/21/2019] [Accepted: 04/27/2019] [Indexed: 12/28/2022] Open
Abstract
Entomopathogenic fungus as well as their toxins is a natural threat surrounding social insect colonies. To defend against them, social insects have evolved a series of unique disease defenses at the colony level, which consists of behavioral and physiological adaptations. These colony-level defenses can reduce the infection and poisoning risk and improve the survival of societal members, and is known as social immunity. In this review, we discuss how social immunity enables the insect colony to avoid, resist and tolerate fungal pathogens. To understand the molecular basis of social immunity, we highlight several genetic elements and biochemical factors that drive the colony-level defense, which needs further verification. We discuss the chemosensory genes in regulating social behaviors, the antifungal secretions such as some insect venoms in external defense and the immune priming in internal defense. To conclude, we show the possible driving force of the fungal toxins for the evolution of social immunity. Throughout the review, we propose several questions involved in social immunity extended from some phenomena that have been reported. We hope our review about social 'host-fungal pathogen' interactions will help us further understand the mechanism of social immunity in eusocial insects.
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Affiliation(s)
- Long Liu
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, China.
- Plant Protection College, Henan Agricultural University, Zhengzhou 450002, China.
| | - Xing-Ying Zhao
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, China.
| | - Qing-Bo Tang
- Plant Protection College, Henan Agricultural University, Zhengzhou 450002, China.
| | - Chao-Liang Lei
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, China.
| | - Qiu-Ying Huang
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, China.
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Cotter SC, Pincheira-Donoso D, Thorogood R. Defences against brood parasites from a social immunity perspective. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180207. [PMID: 30967090 PMCID: PMC6388036 DOI: 10.1098/rstb.2018.0207] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2019] [Indexed: 12/14/2022] Open
Abstract
Parasitic interactions are so ubiquitous that all multicellular organisms have evolved a system of defences to reduce their costs, whether the parasites they encounter are the classic parasites which feed on the individual, or brood parasites which usurp parental care. Many parallels have been drawn between defences deployed against both types of parasite, but typically, while defences against classic parasites have been selected to protect survival, those against brood parasites have been selected to protect the parent's inclusive fitness, suggesting that the selection pressures they impose are fundamentally different. However, there is another class of defences against classic parasites that have specifically been selected to protect an individual's inclusive fitness, known as social immunity. Social immune responses include the anti-parasite defences typically provided for others in kin-structured groups, such as the antifungal secretions produced by termite workers to protect the brood. Defences against brood parasites, therefore, are more closely aligned with social immune responses. Much like social immunity, host defences against brood parasitism are employed by a donor (a parent) for the benefit of one or more recipients (typically kin), and as with social defences against classic parasites, defences have therefore evolved to protect the donor's inclusive fitness, not the survival or ultimately the fitness of individual recipients This can lead to severe conflicts between the different parties, whose interests are not always aligned. Here, we consider defences against brood parasitism in the light of social immunity, at different stages of parasite encounter, addressing where conflicts occur and how they might be resolved. We finish with considering how this approach could help us to address longstanding questions in our understanding of brood parasitism. This article is part of the theme issue 'The coevolutionary biology of brood parasitism: from mechanism to pattern'.
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Affiliation(s)
- S. C. Cotter
- School of Life Sciences, University of Lincoln, Brayford Pool, Lincoln, Lincolnshire LN6 7TS, UK
| | - D. Pincheira-Donoso
- Department of Biosciences, Nottingham Trent University, Clifton Campus, Nottingham, Nottinghamshire NG1 8NS, UK
| | - R. Thorogood
- Helsinki Institute of Life Science (HiLIFE), University of Helsinki, Helsinki, Finland
- Research Programme in Organismal and Evolutionary Biology, Faculty of Biological & Environmental Sciences, University of Helsinki, Helsinki, Finland
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
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