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Pan SH, Sun YH, Tzeng HY, Rodriguez LJ, Bain A. First Evidence of Thalassochory in the Ficus Genus: Seed Dispersal Using the Kuroshio Oceanic Current. PLANTS (BASEL, SWITZERLAND) 2024; 13:1398. [PMID: 38794468 PMCID: PMC11125363 DOI: 10.3390/plants13101398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 04/26/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024]
Abstract
AIM Plants distributed between southern Taiwan and the north of the Philippines are spread among numerous small islands in an area crossed by the powerful Kuroshio current. Oceanic currents can be effective seed-dispersal agents for coastal plant species. Moreover, the Luzon Strait is an area prone to tropical cyclones. The aim of this study is to look at the dispersal capability of an endangered coastal plant species, the Mearns fig (Ficus pedunculosa var. mearnsii), using both experimental and population genetics methods. LOCATION Southern Taiwan, the Philippines, and the islands between Luzon and Taiwan Island. METHODS This study combined two types of analysis, i.e., buoyancy experiments on syconia and double digest restriction-associated DNA sequencing (ddRAD), to analyze the population genetics of the Mearns fig. RESULTS We first discovered that mature Mearns fig syconia could float in seawater. They have a mean float duration of 10 days to a maximum of 21 days. Germination rates varied significantly between Mearns fig seeds that had undergone different durations of flotation treatment. Population genetic analysis shows a high degree of inbreeding among various Mearns fig populations. Moreover, no isolation by distance was found between the populations and individuals. MAIN CONCLUSIONS From our analysis of the genetic structure of the Mearns fig populations, we can clearly highlight the effect of the Kuroshio oceanic current on the seed dispersal of this fig tree. Comprehensive analysis has shown that Mearns fig seeds are still viable before the mature syconium sinks into the seawater, and so they could use the Kuroshio Current to float to the current population locations in Taiwan.
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Affiliation(s)
- Shin-Hung Pan
- Department of Forestry, National Chung-Hsing University, 250 Kuokwang Road, Taichung 40227, Taiwan
| | - Ying-Hsuan Sun
- Department of Forestry, National Chung-Hsing University, 250 Kuokwang Road, Taichung 40227, Taiwan
| | - Hsy-Yu Tzeng
- Department of Forestry, National Chung-Hsing University, 250 Kuokwang Road, Taichung 40227, Taiwan
| | - Lillian Jennifer Rodriguez
- Institute of Biology, National Science Complex, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines
| | - Anthony Bain
- Department of Biological Sciences, National Sun Yat-Sen University, 70 Lienhai Rd., Kaohsiung 80424, Taiwan
- International Ph.D. Program for Science, National Sun Yat-Sen University, 70 Lienhai Rd., Kaohsiung 80424, Taiwan
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2
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Rojas‐Cortés ÁP, Gasca‐Pineda J, González‐Rodríguez A, Ibarra‐Manríquez G. Genomic diversity and structure of a Neotropical microendemic fig tree. Ecol Evol 2024; 14:e11178. [PMID: 38505177 PMCID: PMC10948372 DOI: 10.1002/ece3.11178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 03/06/2024] [Accepted: 03/08/2024] [Indexed: 03/21/2024] Open
Abstract
Genetic diversity is a key component of evolution, and unraveling factors that promote genetic differentiation in space and time is a central question in evolutionary biology. One of the most diverse and ecologically important tree genera in tropical forests worldwide is Ficus (Moraceae). It has been suggested that, given the great dispersal capacity of pollinating fig wasps (Chalcidoidea; Agaonidae), the spatial genetic structure, particularly in monoecious fig species, should be weak. However, no studies have addressed the factors that determine the genetic structure of Ficus species in regions of high geological, geographic, and climatic complexity, such as the Mexican Transition Zone. Using nuclear single nucleotide polymorphisms (5311 SNPs) derived from low-coverage whole genomes and 17 populations, we analyzed the population genomics of Ficus pringlei to characterize neutral and adaptive genetic variation and structure and its association with geographic barriers such as the Trans-Mexican Volcanic Belt, environmental heterogeneity, and wind connectivity. From genomic data of 71 individuals, high genetic diversity, and the identification of three genomic lineages were recorded (North, South, and Churumuco). The results suggest that genetic variation is primarily determined by climatic heterogeneity. Ficus pringlei populations from the north and south of the Trans-Mexican Volcanic Belt also exhibited minimal genetic differentiation (F ST = 0.021), indicating that this mountain range may not act as an insurmountable barrier to gene flow. Wind connectivity is also highlighted in structuring putative adaptive genetic variation, underscoring the intricate complexity of the various factors influencing genetic variation in the species. This study provides information on the possible mechanisms underlying the genetic variation of endemic species of the tropical dry forest of Western Mexico, such as F. pringlei.
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Affiliation(s)
- Ángela P. Rojas‐Cortés
- Instituto de Investigaciones en Ecosistemas y SustentabilidadUniversidad Nacional Autónoma de MéxicoMoreliaMichoacánMexico
- Posgrado en Ciencias BiológicasUniversidad Nacional Autónoma de México, Ciudad UniversitariaCiudad de MéxicoMexico
| | - Jaime Gasca‐Pineda
- Departamento de Ecología EvolutivaInstituto de Ecología, Universidad Nacional Autónoma de México, Circuito exterior s/n anexo al Jardín Botánico, Ciudad UniversitariaCiudad de MéxicoMexico
| | - Antonio González‐Rodríguez
- Instituto de Investigaciones en Ecosistemas y SustentabilidadUniversidad Nacional Autónoma de MéxicoMoreliaMichoacánMexico
| | - Guillermo Ibarra‐Manríquez
- Instituto de Investigaciones en Ecosistemas y SustentabilidadUniversidad Nacional Autónoma de MéxicoMoreliaMichoacánMexico
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3
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Woodruff GC, Willis JH, Phillips PC. Patterns of Genomic Diversity in a Fig-Associated Close Relative of Caenorhabditis elegans. Genome Biol Evol 2024; 16:evae020. [PMID: 38302111 PMCID: PMC10883733 DOI: 10.1093/gbe/evae020] [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: 08/22/2023] [Revised: 01/22/2024] [Accepted: 01/23/2024] [Indexed: 02/03/2024] Open
Abstract
The evolution of reproductive mode is expected to have profound impacts on the genetic composition of populations. At the same time, ecological interactions can generate close associations among species, which can in turn generate a high degree of overlap in their spatial distributions. Caenorhabditis elegans is a hermaphroditic nematode that has enabled extensive advances in developmental genetics. Caenorhabditis inopinata, the sister species of C. elegans, is a gonochoristic nematode that thrives in figs and obligately disperses on fig wasps. Here, we describe patterns of genomic diversity in C. inopinata. We performed RAD-seq on individual worms isolated from the field across three Okinawan island populations. C. inopinata is about five times more diverse than C. elegans. Additionally, C. inopinata harbors greater differences in diversity among functional genomic regions (such as between genic and intergenic sequences) than C. elegans. Conversely, C. elegans harbors greater differences in diversity between high-recombining chromosome arms and low-recombining chromosome centers than C. inopinata. FST is low among island population pairs, and clear population structure could not be easily detected among islands, suggesting frequent migration of wasps between islands. These patterns of population differentiation appear comparable with those previously reported in its fig wasp vector. These results confirm many theoretical population genetic predictions regarding the evolution of reproductive mode and suggest C. inopinata population dynamics may be driven by wasp dispersal. This work sets the stage for future evolutionary genomic studies aimed at understanding the evolution of sex as well as the evolution of ecological interactions.
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Affiliation(s)
- Gavin C Woodruff
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
- Present address: Department of Biology, University of Oklahoma, Norman, OK 73019, USA
| | - John H Willis
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - Patrick C Phillips
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
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4
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Di Giusto B, Bain A. Local ecological factors, not interference competition, drive the foundress number of two species of fig wasp sharing Ficus septica figs. PLoS One 2024; 19:e0290439. [PMID: 38165887 PMCID: PMC10760673 DOI: 10.1371/journal.pone.0290439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 08/08/2023] [Indexed: 01/04/2024] Open
Abstract
Recent studies have challenged assumptions about the classic fig-fig wasp pollination mutualism model, suggesting that further investigation into the receptive phase of fig development is needed. This study assessed the pollination mechanisms of Ficus septica in southern Taiwan and identified two species of wasps as the primary pollinators. Machine learning was used to identify and rank the factors that explain the relative abundance of these wasps. The two wasp species showed the highest level of cohabitation ever reported in the literature, with three-quarters of the figs containing multiple foundresses. The study also reported re-emerged foundresses and a 10% ratio of pollinated figs without foundresses. Local factors, such as the sampling period and tree identity, were the best predictors of the presence and number of each foundress species, with fig size also affecting the number of foundresses. The study highlights the variability in pollinator abundance between figs, crops, and trees. It also shows that the local environment of the trees and the availability of figs are crucial factors in determining which figs the pollinator wasps choose. These findings challenge assumptions about the classic mutualism model and suggest that long-term surveys are needed to estimate the relative contributions of each partner and provide data for evolutionary and ecological models. This study also provides valuable insights into the factors that affect the abundance and interactions of pollinator wasps during the receptive phase of fig development, with implications for understanding the behaviour of pollinating wasps and advancing our knowledge of population dynamics in Ficus species.
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Affiliation(s)
- Bruno Di Giusto
- Journalism and Mass Communication Program, International College, Ming Chuan University, Taipei, Taiwan
| | - Anthony Bain
- Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan
- International Ph.D. Program for Science, National Sun Yat-Sen University, Kaohsiung, Taiwan
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5
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Deng X, Liao Y, Wong D, Yu H. The genetic structuring in pollinating wasps of Ficus hispida in continental Asia. Ecol Evol 2023; 13:e10518. [PMID: 37745788 PMCID: PMC10511832 DOI: 10.1002/ece3.10518] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/26/2023] [Accepted: 08/29/2023] [Indexed: 09/26/2023] Open
Abstract
The interaction between figs and fig wasps provides a striking example of obligate brood site pollination mutualism. Monoecious figs, constituting independent radiations in each tropical biome, are present in significant proportions worldwide, but in continental Asia, dioecious figs have diverged into various niches, making the region's assemblage remarkably diverse. However, the reproductive success of figs and fig wasps largely depends on the fig wasp dispersal process. Monoecious fig pollinators in continental Asian tropical rain forests exhibit high gene flow of the plant, while many dioecious fig pollinators have a more restricted gene flow. However, there are limited studies on the genetic structure of dioecious Ficus pollinators that pollinate figs with intermediate gene flow. Here, we used molecular methods to investigate the genetic structure of pollinating wasps of the widely distributed dioecious Ficus hispida in China and Southeast Asia. Sequence data from two gene regions were used: the mitochondrial protein-coding gene cytochrome c oxidase subunit I (COI) and the nuclear 28S genes. Both molecular and morphological results support two fig wasp species at our sampling sites. Our findings suggest that for widely sympatric Ficus species in continental Asia, monoecious figs presenting long gene glow have the fewest fig wasp species, followed by dioecious figs presenting intermediate gene flow, and dioecious figs presenting local gene flow have the most fig wasp species.
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Affiliation(s)
- Xiaoxia Deng
- Key Laboratory of Plant Resource Conservation and Sustainable UtilizationSouth China Botanical Garden, CASGuangzhouChina
- South China National Botanical GardenGuangzhouChina
- CEFECNRS, Univ Montpellier, EPHE, IRDMontpellierFrance
| | - Yaolin Liao
- Key Laboratory of Plant Resource Conservation and Sustainable UtilizationSouth China Botanical Garden, CASGuangzhouChina
- South China National Botanical GardenGuangzhouChina
| | - Da‐Mien Wong
- Key Laboratory of Plant Resource Conservation and Sustainable UtilizationSouth China Botanical Garden, CASGuangzhouChina
- South China National Botanical GardenGuangzhouChina
| | - Hui Yu
- Key Laboratory of Plant Resource Conservation and Sustainable UtilizationSouth China Botanical Garden, CASGuangzhouChina
- South China National Botanical GardenGuangzhouChina
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Chou PA, Bain A, Chantarasuwan B, Tzeng HY. Parasitism Features of a Fig Wasp of Genus Apocrypta (Pteromalidae: Pteromalinae) Associated with a Host Belonging to Ficus Subgenus Ficus. INSECTS 2023; 14:insects14050437. [PMID: 37233065 DOI: 10.3390/insects14050437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/25/2023] [Accepted: 04/29/2023] [Indexed: 05/27/2023]
Abstract
Non-pollinating fig wasps (NPFWs), particularly long-ovipositored Sycoryctina wasps, exhibit a high species specificity and exert complex ecological effects on the obligate mutualism between the plant genus Ficus and pollinating fig wasps. Apocrypta is a genus of NPFWs that mostly interacts with the Ficus species under the subgenus Sycomorus, and the symbiosis case between Apocrypta and F. pedunculosa var. mearnsii, a Ficus species under subgenus Ficus, is unique. As fig's internal environments and the wasp communities are distinct between the two subgenera, we addressed the following two questions: (1) Are the parasitism features of the Apocrypta wasp associated with F. pedunculosa var. mearnsii different from those of other congeneric species? (2) Is this Apocrypta species an efficient wasp that lives in its unique host? Our observation revealed that this wasp is an endoparasitic idiobiont parasitoid, as most congeneric species are, but developed a relatively long ovipositor. Furthermore, the relationships of the parasitism rate versus the pollinator number, the fig wall, and the sex ratio of the pollinator, respectively, showed that it possessed a higher parasitism ability than that of other congeners. However, its parasitism rate was low, and thus it was not an efficient wasp in its habitat. This difference between parasitism ability and parasitism rate might be a consequence of its oviposition strategy and the severe habitat conditions. These findings may also provide insights into the mechanism to maintain the interaction between the fig tree and the fig wasp community.
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Affiliation(s)
- Po-An Chou
- Department of Forestry, National Chung Hsing University, No. 145 Xingda Rd., Taichung City 40227, Taiwan
| | - Anthony Bain
- Department of Biological Science, National Sun Yat-sen University, No. 70 Lien-Hai Rd., Kaohsiung City 80424, Taiwan
| | | | - Hsy-Yu Tzeng
- Department of Forestry, National Chung Hsing University, No. 145 Xingda Rd., Taichung City 40227, Taiwan
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Deng X, Liao Y, Liu W, Yu H. The coexistence of two related fig wasp species sharing the same host fig species across a broad geographical area. ACTA OECOLOGICA 2023. [DOI: 10.1016/j.actao.2022.103885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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8
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Olfactory and gustatory receptor genes in fig wasps: Evolutionary insights from comparative studies. Gene 2023; 850:146953. [PMID: 36243214 DOI: 10.1016/j.gene.2022.146953] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 09/17/2022] [Accepted: 10/03/2022] [Indexed: 11/07/2022]
Abstract
The mechanisms of chemoreception in fig wasps (Hymenoptera, Agaonidae) are of primary importance in their co-evolutionary relationship with the fig trees they pollinate. We used transcriptome sequences of 25 fig wasps in six genera that allowed a comparative approach to the evolution of key molecular components of fig wasp chemoreception: their odorant (OR) and gustatory (GR) receptor genes. In total, we identified 311 ORs and 47 GRs, with each species recording from 5 to 30 OR genes and 1-4 GR genes. 304 OR genes clustered into 18 orthologous groups known to be sensitive to cuticular hydrocarbons (CHC), pheromones, acids, alcohols and a variety of floral scents such as cineole, Linalool, and Heptanone. 45 GR genes clustered into 4 orthologous groups that contain sweet, bitter, CO2 and undocumented receptors. Gene sequences in most orthologous groups varied greatly among species, except for ORco (60.0% conserved) and sweet receptors (30.7% conserved). Strong purifying selection of both odorant and gustatory genes was detected, as shown by low ω values. Signatures of positive selection were detected in loci from both OR and GR orthologous groups. Fig wasps have relatively few olfactory and especially gustatory receptors, reflecting the natural history of the system. Amino acid sequences nonetheless vary significantly between species and are consistent with the phylogenetic relationships among fig wasps. The differences in ORs within some orthologous groups from the same species, but different hosts and from closely related species from one host can reach as low as 49.3% and 9.8% respectively, implying the ORs of fig wasps can evolve rapidly to novel ecological environments. Our results provide a starting point for understanding the molecular basis of the chemosensory systems of fig wasps.
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Deng X, Cheng Y, Peng YQ, Yu H, Proffit M, Kjellberg F. Overlaps in olfactive signalling coupled with geographic variation may result in localised pollinator sharing between closely related Ficus species. BMC Ecol Evol 2022; 22:97. [PMID: 35964015 PMCID: PMC9375327 DOI: 10.1186/s12862-022-02055-0] [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: 12/29/2021] [Accepted: 07/18/2022] [Indexed: 11/10/2022] Open
Abstract
Background In brood site pollination mutualisms, pollinators are attracted by odours emitted at anthesis. In Ficus, odours of receptive figs differ among species and the specific pollinators generally only enter figs of their host species ensuring a pre-zygotic barrier to plant interspecific hybridisation. However, field observations recorded that, in Guangdong province in China, Valisia javana hilli, the local pollinator of F. hirta, entered and reproduced successfully in the figs of the closely related F. triloba on a regular basis. We propose that closely related Ficus species produce similar receptive fig odours. Under particular contexts of odours locally present, the receptive fig odours of non-host figs of a Ficus species may become attractive to pollinators of closely related Ficus species. We used the headspace technique to collect in situ receptive fig odours of F. triloba in a series of locations in China. Under controlled conditions, we tested the attraction of fig pollinating wasps from F. hirta and F. triloba to host figs and non-host figs in Y tube experiments. Results Receptive fig odours of F. triloba though different from those of F. hirta, were mainly composed of a same set of volatile organic compounds. When given the choice between receptive fig odours and air, the pollinating wasps were only attracted by their host’s odours. However, when given a choice between host and non-host figs the pollinators of F. hirta were equally attracted by the two odours while the pollinators of F. triloba tended to be more attracted by their host’s fig odours. Conclusions Receptive fig odours vary geographically within species and the differentiation of receptive fig odours between closely related Ficus species is often incomplete. This allows localised or occasional pollinator sharing following different modalities. Cross stimulation when wasps are exposed simultaneously to odours of host and non-host species may be important. While occasional pollinator sharing may play a marginal role when wasp populations are robust, it may ensure the provisioning of new pollinators from the closest relative of a Ficus species if its pollinators go extinct.
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Xie H, Yang P, Xia Y, Kjellberg F, Darwell CT, Li ZB. Maintenance of specificity in sympatric host-specific fig/wasp pollination mutualisms. PeerJ 2022; 10:e13897. [PMID: 35975234 PMCID: PMC9375967 DOI: 10.7717/peerj.13897] [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: 02/17/2022] [Accepted: 07/22/2022] [Indexed: 01/19/2023] Open
Abstract
Background Fig/wasp pollination mutualisms are extreme examples of species-specific plant-insect symbioses, but incomplete specificity occurs, with potentially important evolutionary consequences. Why pollinators enter alternative hosts, and the fates of pollinators and the figs they enter, are unknown. Methods We studied the pollinating fig wasp, Ceratosolen emarginatus, which concurrently interacts with its typical host Ficus auriculata and the locally sympatric alternative host F. hainanensis, recording frequencies of the wasp in figs of the alternative hosts. We measured ovipositor lengths of pollinators and style lengths in female and male figs in the two host species. Volatile organic compounds (VOCs) emitted by receptive figs of each species were identified using GC-MS. We tested the attraction of wasps to floral scents in choice experiments, and detected electrophysiologically active compounds by GC-EAD. We introduced C. emarginatus foundresses into figs of both species to reveal the consequences of entry into the alternative host. Results C. emarginatus entered a low proportion of figs of the alternative host, and produced offspring in a small proportion of them. Despite differences in the VOC profiles of the two fig species, they included shared semiochemicals. Although C. emarginatus females prefer receptive figs of F. auriculata, they are also attracted to those of F. hainanensis. C. emarginatus that entered male figs of F. hainanensis produced offspring, as their ovipositors were long enough to reach the bottom of the style; however, broods were larger and offspring smaller than in the typical host. Female figs of F. hainanensis failed to produce seeds when visited by C. emarginatus. These findings advance our current understanding of how these species-specific mutualisms usually remain stable and the conditions that allow their diversification.
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Affiliation(s)
- Hua Xie
- Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Southwest Forestry University, Kunming, Yunnan, China
| | - Pei Yang
- Yunnan University of Chinese Medicine, Kunming, Yunnan, China
| | - Yan Xia
- Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Southwest Forestry University, Kunming, Yunnan, China
| | - Finn Kjellberg
- CEFE, CNRS, Université de Montpellier, EPHE, IRD, Montpellier, France
| | - Clive T. Darwell
- Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Zong-Bo Li
- Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Southwest Forestry University, Kunming, Yunnan, China
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Wong DM, Fan S, Yu H. Seven Sycoryctine Fig Wasp Species (Chalcidoidea: Pteromalidae) Associated with Dioecious Ficus hirta Inhabiting South China and Southeast Asia. BIOLOGY 2022; 11:801. [PMID: 35741322 PMCID: PMC9219999 DOI: 10.3390/biology11060801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 05/18/2022] [Indexed: 06/15/2023]
Abstract
Even though non-pollinating fig wasps are essential components in tropical and subtropical habitats, yet they are poorly described in the Oriental communities. This study presented seven new sycoryctine fig wasp species associated with Ficus hirta fig trees inhabiting South China and Southeast Asia. These new sycoryctine species belong to the genera Philotrypesis, Sycoryctes, and Sycoscapter. They can be easily distinguished by their adaptive morphologies such as face sculpture, body-color, and ovipositors. An identification key is provided to differentiate between them, and the relationships with their host fig trees are also discussed. The holotypes and paratypes are both deposited in the South China Botanical Garden, Chinese Academy of Sciences, China.
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Affiliation(s)
- Da-Mien Wong
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China; (D.-M.W.); (S.F.)
- Key Laboratory of Plant Resource Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- Guangdong Provincial Key Laboratory of Digital Botanical Garden, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Songle Fan
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China; (D.-M.W.); (S.F.)
- Key Laboratory of Plant Resource Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- Guangdong Provincial Key Laboratory of Digital Botanical Garden, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Hui Yu
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China; (D.-M.W.); (S.F.)
- Key Laboratory of Plant Resource Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- Guangdong Provincial Key Laboratory of Digital Botanical Garden, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
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Pollinator sharing, copollination, and speciation by host shifting among six closely related dioecious fig species. Commun Biol 2022; 5:284. [PMID: 35396571 PMCID: PMC8993897 DOI: 10.1038/s42003-022-03223-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 03/04/2022] [Indexed: 12/11/2022] Open
Abstract
The obligate pollination mutualism between figs (Ficus, Moraceae) and pollinator wasps (Agaonidae, Hymenoptera) is a classic example of cospeciation. However, examples of phylogenetic incongruencies between figs and their pollinators suggest that pollinators may speciate by host shifting. To investigate the mechanism of speciation by host shifting, we examined the phylogenetic relationships and population genetic structures of six closely related fig species and their pollinators from southern China and Taiwan-Ryukyu islands using various molecular markers. The results revealed 1) an extraordinary case of pollinator sharing, in which five distinct fig species share a single pollinator species in southern China; 2) two types of copollination, namely, sympatric copollination by pollinator duplication or pollinator migration, and allopatric copollination by host migration and new pollinator acquisition; 3) fig species from southern China have colonized Taiwan repeatedly and one of these events has been followed by host shifting, reestablishment of host specificity, and pollinator speciation, in order. Based on our results, we propose a model for pollinator speciation by host shifting in which the reestablishment of host-specificity plays a central role in the speciation process. These findings provide important insights into understanding the mechanisms underlying pollinator speciation and host specificity in obligate pollination mutualism. Phylogenetic and population genetic analyses reveal mechanisms of pollinator sharing, copollination and speciation by host-shift in fig-wasp mutualism.
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Yu H, Zhang Z, Liu L, Cheng Y, Deng X, Segar ST, Compton SG. Asymmetric sharing of pollinator fig wasps between two sympatric dioecious fig trees: a reflection of supply and demand or differences in the size of their figs? BOTANICAL STUDIES 2022; 63:7. [PMID: 35316420 PMCID: PMC8941105 DOI: 10.1186/s40529-022-00338-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 03/03/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Host specificity among pollinator fig wasps (Agaonidae) depends on host plant specific volatile cues, but fig wasps must also pass through a narrow physical barrier (the ostiole) if they are to pollinate and oviposit. Across South East Asia the dioecious shrub Ficus hirta is associated with at least ten pollinator species allied to Valisia javana. Ficus triloba has a single recorded pollinator, Valisia esquirolianae. Receptive figs of F. hirta are usually much smaller than those of F. triloba, but at a mainland site where F. hirta has atypically large figs we identified both V. esquirolianae and V. javana from both Ficus species using COI and ITS2 sequencing. To investigate whether this host overlap was exceptional we reared fig wasps from the two trees elsewhere and recorded features that may facilitate host transfer between them, including attractant volatiles, reproductive phenology and the sizes of their figs and fig wasps. RESULTS The two Ficus species were found to support both Valisia species at several of the sites, suggesting that the differences we detected in volatile profiles, ostiole sizes and pollinator head sizes are not strict barriers to host sharing. Valisia javana colonised F. triloba more frequently than V. esquirolianae colonised F. hirta. CONCLUSIONS This asymmetric sharing of pollinators may reflect the relative abundance of the two species of fig wasps and differences in host reproductive phenology. Asynchronous flowering of individual F. hirta may favor local retention of pollinators, in contrast to the tree-wide synchrony of F. triloba figs, which can generate local shortages of V. esquirolianae. If the pollinator sharing by male figs of F. triloba and F. hirta also occurs in female figs then this could result in gene flow between them.
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Affiliation(s)
- Hui Yu
- School of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China.
- Guangdong Provincial Key Laboratory of Applied Botany and Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou, 510650, China.
- South China Botanical Garden, The Chinese Academy of Sciences, Xingke Road 723, Tianhe district, Guangzhou, 510650, China.
| | - Zhiwei Zhang
- School of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - Lu Liu
- Guangdong Provincial Key Laboratory of Applied Botany and Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Yufen Cheng
- Guangdong Provincial Key Laboratory of Applied Botany and Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Xiaoxia Deng
- Guangdong Provincial Key Laboratory of Applied Botany and Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Simon T Segar
- Department of Crop and Environment Sciences, Harper Adams University, Newport, TF10 8NB, UK
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14
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Greeff JM, Kjellberg F. Pollinating fig wasps' simple solutions to complex sex ratio problems: a review. Front Zool 2022; 19:3. [PMID: 35022069 PMCID: PMC8756665 DOI: 10.1186/s12983-021-00447-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 11/19/2021] [Indexed: 11/28/2022] Open
Abstract
Local mate competition (LMC) favours female biased clutch sex ratios because it reduces competition between brothers and provides extra mating opportunities for sons. Fig wasps seem to fit LMC model assumptions and lay female-biased sex ratios as predicted. These female biased sex ratios increase fitness greatly. In line with predictions, their sex ratios become less female-biased as the number of mothers laying in the same fig increases. However, this variation results in comparatively small fitness benefits compared to just biased ratios and data suggest substantial mismatches with LMC theory. The mismatches are due to several factors. (1) Multiple foundresses typically lay too many daughters. (2) Single foundress sex ratios are explained by sequential oviposition and ladies-last models. (3) Mortality that typically exceeds 10% may decouple the link between primary sex ratios, the focus of model predictions, and secondary sex ratios of adult wasps that are counted by researchers. (4) Model assumptions are frequently violated: (a) clutch sizes are unequal, (b) oviposition may not be simultaneous (c) cryptic/multiple wasp species inhabit the same host, (d) foundress numbers are systematically undercounted, (e) inbreeding coefficient calculations are inaccurate, and (f) male wasps sometimes disperse. These data and calculations suggest that alternative explanations must be considered seriously. Substantial data show that wasps typically lay most of their male eggs first followed by mostly female eggs require a new approach. These "slope" strategies result in more accurate sex ratios that are automatically adjusted to foundress number, own and relative clutch sizes and to sequential clutches. This effect will alter sex ratios in all species once the egg capacity of a fig is crossed or when interference reduces clutch sizes. In addition to this passive response, the females of about half the studied species have a conditional response that reduces female bias under higher foundress numbers by laying more sons. Therefore, wasps seem to use a very simple strategy that increases their fitness. Natural selection could have optimized parameters of the slope strategy and possibly the existence of the slope strategy itself. Variation in the slope strategy that is the result of natural selection is adaptive. Research should therefore focus on quantifying variables of this slope strategy. Currently, it is unclear how much of the variation is adaptive as opposed to being coincidental by-products.
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Affiliation(s)
- Jaco M Greeff
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa.
| | - Finn Kjellberg
- CEFE, CNRS, Univ Montpellier, EPHE, IRD, Montpellier, France
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15
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Kiourtsoglou A, Kaliontzopoulou A, Poursanidis D, Jablonski D, Lymberakis P, Poulakakis N. Evidence of cryptic diversity in
Podarcis peloponnesiacus
and re‐evaluation of its current taxonomy; insights from genetic, morphological, and ecological data. J ZOOL SYST EVOL RES 2021. [DOI: 10.1111/jzs.12540] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Athina Kiourtsoglou
- Department of Biology School of Sciences and Engineering University of Crete Heraklion Greece
- Natural History Museum of Crete School of Sciences and Engineering University of Crete Heraklion Greece
| | - Antigoni Kaliontzopoulou
- CIBIO‐InBIO Centro de Investigação em Biodiversidade e Recursos Genéticos Universidade do Porto Vairão Portugal
| | - Dimitris Poursanidis
- Institute of Applied and Computational Mathematics Foundation for Research and Technology ‐ Hellas Heraklion Greece
| | - Daniel Jablonski
- Department of Zoology Comenius University in Bratislava Bratislava Slovakia
| | - Petros Lymberakis
- Natural History Museum of Crete School of Sciences and Engineering University of Crete Heraklion Greece
| | - Nikos Poulakakis
- Department of Biology School of Sciences and Engineering University of Crete Heraklion Greece
- Natural History Museum of Crete School of Sciences and Engineering University of Crete Heraklion Greece
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16
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Yu H, Liao Y, Cheng Y, Jia Y, Compton SG. More examples of breakdown the 1:1 partner specificity between figs and fig wasps. BOTANICAL STUDIES 2021; 62:15. [PMID: 34626257 PMCID: PMC8502184 DOI: 10.1186/s40529-021-00323-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 09/21/2021] [Indexed: 05/22/2023]
Abstract
BACKGROUND The obligate mutualism between fig trees (Ficus, Moraceae) and pollinating fig wasps (Agaonidae) is a model system for studying co-evolution due to its perceived extreme specificity, but recent studies have reported a number of examples of trees pollinated by more than one fig wasp or sharing pollinators with other trees. This will make the potential of pollen flow between species and hybridization more likely though only few fig hybrids in nature have been found. We reared pollinator fig wasps from figs of 13 Chinese fig tree species and established their identity using genetic methods in order to investigate the extent to which they were supporting more than one species of pollinator (co-pollinator). RESULTS Our results showed (1) pollinator sharing was frequent among closely-related dioecious species (where pollinator offspring and seeds develop on different trees); (2) that where two pollinator species were developing in figs of one host species there was usually one fig wasp with prominent rate than the other. An exception was F. triloba, where its two pollinators were equally abundant; (3) the extent of co-pollinator within one fig species is related to the dispersal ability of them which is stronger in dioecious figs, especially in small species. CONCLUSIONS Our results gave more examples to the breakdown of extreme specificity, which suggest that host expansion events where pollinators reproduce in figs other than those of their usual hosts are not uncommon among fig wasps associated with dioecious hosts. Because closely related trees typically have closely related pollinators that have a very similar appearance, the extent of pollinator-sharing has probably been underestimated. Any pollinators that enter female figs carrying heterospecific pollen could potentially generate hybrid seed, and the extent of hybridization and its significance may also have been underestimated.
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Affiliation(s)
- Hui Yu
- Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou, 510650, China.
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China.
- Centre for Plant Ecology, CAS Core Botanical Gardens, Guangzhou, China.
| | - Yaolin Liao
- Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Yufen Cheng
- Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Yongxia Jia
- Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou, 510650, China
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17
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Tong X, Ding YY, Deng JY, Wang R, Chen XY. Source-sink dynamics assists the maintenance of a pollinating wasp. Mol Ecol 2021; 30:4695-4707. [PMID: 34347898 DOI: 10.1111/mec.16104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 07/22/2021] [Accepted: 07/28/2021] [Indexed: 12/29/2022]
Abstract
Dispersal that unites spatially subdivided populations into a metapopulation with source-sink dynamics is crucial for species persistence in fragmented landscapes. Understanding such dynamics for pollinators is particularly urgent owing to the ongoing global pollination crisis. Here, we investigated the population structure and source-sink dynamics of a pollinating wasp (Wiebesia sp. 3) of Ficus pumila in the Zhoushan Archipelago of China. We found significant asymmetry in the pairwise migrant numbers for 22 of 28 cases on the historical timescale, but only two on the contemporary timescale. Despite a small population size, the sole island not colonized by a superior competitor wasp (Wiebesia sp. 1) consistently behaved as a net exporter of migrants, supplying large sinks. Comparable levels of genetic diversity, with few private alleles and low genetic differentiation (total Fst : 0.03; pairwise Fst : 0.0005-0.0791), were revealed among all the islands. There was a significant isolation-by-distance pattern caused mainly by migration between the competition-free island and other islands, otherwise the pattern was negligible. The clustering analysis failed to detect multiple gene pools for the whole region. Thus, the sinks were most probably organized into a patchy population. Moreover, the estimates of effective population sizes were comparable between the two timescales. Thus the source-sink dynamics embedded within a well-connected population network may allow Wiebesia sp. 3 to persist at a competitive disadvantage. This study provides evidence that metapopulations in the real world may be complicated and changeable over time, highlighting the necessity to study such metapopulations in detail.
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Affiliation(s)
- Xin Tong
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Yuan-Yuan Ding
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Jun-Yin Deng
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Rong Wang
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China.,Shanghai Institute of Pollution Control and Ecological Security, Shanghai, China
| | - Xiao-Yong Chen
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China.,Shanghai Institute of Pollution Control and Ecological Security, Shanghai, China
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18
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Deng X, Chen L, Tian E, Zhang D, Wattana T, Yu H, Kjellberg F, Segar ST. Low host specificity and broad geographical ranges in a community of parasitic non-pollinating fig wasps (Sycoryctinae; Chalcidoidea). J Anim Ecol 2021; 90:1678-1690. [PMID: 33738802 DOI: 10.1111/1365-2656.13483] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 02/26/2021] [Indexed: 12/23/2022]
Abstract
Plants, phytophagous insects and their parasitoids form the most diverse assemblages of macroscopic organisms on earth. Enclosed assemblages in particular represent a tractable system for studying community assembly and diversification. Communities associated with widespread plant species are especially suitable as they facilitate a comparative approach. Pantropical fig-wasp communities represent a remarkably well-replicated system, ideal for studying these historical processes. We expect high dispersal ability in non-pollinating fig wasps to result in lower geographical turnover in comparison to pollinating fig wasps. The ability of non-pollinating wasps to utilise a number of hosts (low host specificity) is a key determinant of overall geographical range, with intraspecific competition becoming a constraining factor should diet breadth overlap among species. Finally, we expect conserved community structure throughout the host range. We aim to test these expectations, derived from population genetic and community studies, using the multi-trophic insect community associated with Ficus hirta throughout its 3,500 km range across continental and insular Asia. We collect molecular evidence from one coding mitochondrial gene, one non-coding nuclear gene and multiple microsatellites across 25 geographical sites. Using these data, we establish species boundaries, determine levels of host specificity among non-pollinating fig wasps and quantify geographical variation in community composition. We find low host specificity in two genera of non-pollinating fig wasps. Functional community structure is largely conserved across the range of the host fig, despite limited correspondence between the ranges of non-pollinator and pollinator species. While nine pollinators are associated with Ficus hirta, the two non-pollinator tribes developing in its figs each contained only four species. Contrary to predictions, we find stronger isolation by distance in non-pollinators than pollinators. Long-lived non-pollinators may disperse more gradually and be less reliant on infrequent long-distance dispersal by wind currents. Segregation among non-pollinating species across their range is suggestive of competitive exclusion and we propose that this may be a result of increased levels of local adaptation and moderate, but regular, rates of dispersal. Our findings provide one more example of lack of strict codiversification in the geographical diversification of plant-associated insect communities.
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Affiliation(s)
- Xiaoxia Deng
- Key Laboratory of Plant Resource Conservation and Sustainable Utilization, South China Botanical Garden, CAS, Guangzhou, China.,Centre for Plant Ecology, CAS Core Botanical Gardens, Guangzhou, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Lianfu Chen
- Key Laboratory of Plant Resource Conservation and Sustainable Utilization, South China Botanical Garden, CAS, Guangzhou, China.,Centre for Plant Ecology, CAS Core Botanical Gardens, Guangzhou, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Enwei Tian
- Key Laboratory of Plant Resource Conservation and Sustainable Utilization, South China Botanical Garden, CAS, Guangzhou, China
| | - Dayong Zhang
- State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, China
| | | | - Hui Yu
- Key Laboratory of Plant Resource Conservation and Sustainable Utilization, South China Botanical Garden, CAS, Guangzhou, China.,Centre for Plant Ecology, CAS Core Botanical Gardens, Guangzhou, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Finn Kjellberg
- CEFE, University of Montpellier, CNRS, University of Paul Valéry Montpellier, EPHE, IRD, Montpellier Cedex 5, France
| | - Simon T Segar
- Agriculture and Environment Department, Harper Adams University, Newport, UK
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19
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Chomicki G, Kiers ET, Renner SS. The Evolution of Mutualistic Dependence. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2020. [DOI: 10.1146/annurev-ecolsys-110218-024629] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
While the importance of mutualisms across the tree of life is recognized, it is not understood why some organisms evolve high levels of dependence on mutualistic partnerships, while other species remain autonomous or retain or regain minimal dependence on partners. We identify four main pathways leading to the evolution of mutualistic dependence. Then, we evaluate current evidence for three predictions: ( a) Mutualisms with different levels of dependence have distinct stabilizing mechanisms against exploitation and cheating, ( b) less dependent mutualists will return to autonomy more often than those that are highly dependent, and ( c) obligate mutualisms should be less context dependent than facultative ones. Although we find evidence supporting all three predictions, we stress that mutualistic partners follow diverse paths toward—and away from—dependence. We also highlight the need to better examine asymmetry in partner dependence. Recognizing how variation in dependence influences the stability, breakdown, and context dependence of mutualisms generates new hypotheses regarding how and why the benefits of mutualistic partnerships differ over time and space.
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Affiliation(s)
- Guillaume Chomicki
- Department of Bioscience, Durham University, Durham DH1 3LE, United Kingdom
| | - E. Toby Kiers
- Department of Ecological Science, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands
| | - Susanne S. Renner
- Systematic Botany and Mycology, Department of Biology, University of Munich (LMU), 80638 Munich, Germany
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20
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Affiliation(s)
- Alicia Toon
- School of Biological Sciences; The University of Queensland; Brisbane Queensland 4072 Australia
| | - L. Irene Terry
- School of Biological Sciences; University of Utah; Salt Lake City Utah USA
| | | | - Gimme H. Walter
- School of Biological Sciences; The University of Queensland; Brisbane Queensland 4072 Australia
| | - Lyn G. Cook
- School of Biological Sciences; The University of Queensland; Brisbane Queensland 4072 Australia
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21
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Cooper L, Bunnefeld L, Hearn J, Cook JM, Lohse K, Stone GN. Low-coverage genomic data resolve the population divergence and gene flow history of an Australian rain forest fig wasp. Mol Ecol 2020; 29:3649-3666. [PMID: 32567765 DOI: 10.1111/mec.15523] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 06/09/2020] [Accepted: 06/12/2020] [Indexed: 12/16/2022]
Abstract
Population divergence and gene flow are key processes in evolution and ecology. Model-based analysis of genome-wide data sets allows discrimination between alternative scenarios for these processes even in nonmodel taxa. We used two complementary approaches (one based on the blockwise site frequency spectrum [bSFS], the second on the pairwise sequentially Markovian coalescent [PSMC]) to infer the divergence history of a fig wasp, Pleistodontes nigriventris. Pleistodontes nigriventris and its fig tree mutualist Ficus watkinsiana are restricted to rain forest patches along the eastern coast of Australia and are separated into The Northern population is to the north of the Southern populations by two dry forest corridors (the Burdekin and St. Lawrence Gaps). We generated whole genome sequence data for two haploid males per population and used the bSFS approach to infer the timing of divergence between northern and southern populations of P. nigriventris, and to discriminate between alternative isolation with migration (IM) and instantaneous admixture (ADM) models of postdivergence gene flow. Pleistodontes nigriventris has low genetic diversity (π = 0.0008), to our knowledge one of the lowest estimates reported for a sexually reproducing arthropod. We find strongest support for an ADM model in which the two populations diverged ca. 196 kya in the late Pleistocene, with almost 25% of northern lineages introduced from the south during an admixture event ca. 57 kya. This divergence history is highly concordant with individual population demographies inferred from each pair of haploid males using PSMC. Our analysis illustrates the inferences possible with genome-level data for small population samples of tiny, nonmodel organisms and adds to a growing body of knowledge on the population structure of Australian rain forest taxa.
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Affiliation(s)
- Lisa Cooper
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | - Lynsey Bunnefeld
- Biological and Environmental Sciences, University of Stirling, Stirling, UK
| | - Jack Hearn
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK.,Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, UK
| | - James M Cook
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Konrad Lohse
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | - Graham N Stone
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
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22
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Deng JY, Fu RH, Compton SG, Liu M, Wang Q, Yuan C, Zhang LS, Chen Y. Sky islands as foci for divergence of fig trees and their pollinators in southwest China. Mol Ecol 2020; 29:762-782. [PMID: 31943487 DOI: 10.1111/mec.15353] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 11/26/2019] [Accepted: 01/03/2020] [Indexed: 12/11/2022]
Abstract
The dynamics of populations and their divergence over time have shaped current levels of biodiversity and in the case of the "sky islands" of mountainous southwest (SW) China have resulted in an area of exceptional botanical diversity. Ficus tikoua is a prostrate fig tree subendemic to the area that displays unique intraspecific diversity, producing figs typical of different pollination modes in different parts of its range. By combining climate models, genetic variation in populations of the tree's obligate fig wasp pollinators and distributions of the different plant phenotypes, we examined how this unusual situation may have developed. We identified three genetically distinct groups of a single Ceratosolen pollinator species that have largely parapatric distributions. The complex topography of the region contributed to genetic divergence among the pollinators by facilitating geographical isolation and providing refugia. Migration along elevations in response to climate oscillations further enhanced genetic differentiation of the three pollinator groups. Their distributions loosely correspond to the distributions of the functionally significant morphological differences in the male figs of their host plants, but postglacial expansion of one group has not been matched by spread of its associated plant phenotype, possibly due to a major river barrier. The results highlight how interplay between the complex topography of the "sky island" complex and climate change has shaped intraspecies differentiation and relationships between the plant and its pollinator. Similar processes may explain the exceptional botanical diversity of SW China.
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Affiliation(s)
- Jun-Yin Deng
- Ecological Security and Protection Key Laboratory of Sichuan Province, Mianyang Normal University, Mianyang, China.,Division of Genetics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Rong-Hua Fu
- Ecological Security and Protection Key Laboratory of Sichuan Province, Mianyang Normal University, Mianyang, China
| | | | - Mei Liu
- Ecological Security and Protection Key Laboratory of Sichuan Province, Mianyang Normal University, Mianyang, China
| | - Qin Wang
- Ecological Security and Protection Key Laboratory of Sichuan Province, Mianyang Normal University, Mianyang, China
| | - Chuan Yuan
- Ecological Security and Protection Key Laboratory of Sichuan Province, Mianyang Normal University, Mianyang, China
| | - Lu-Shui Zhang
- Ecological Security and Protection Key Laboratory of Sichuan Province, Mianyang Normal University, Mianyang, China
| | - Yan Chen
- Ecological Security and Protection Key Laboratory of Sichuan Province, Mianyang Normal University, Mianyang, China
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23
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Satler JD, Herre EA, Jandér KC, Eaton DAR, Machado CA, Heath TA, Nason JD. Inferring processes of coevolutionary diversification in a community of Panamanian strangler figs and associated pollinating wasps. Evolution 2019; 73:2295-2311. [PMID: 31339553 DOI: 10.1111/evo.13809] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 07/18/2019] [Indexed: 12/27/2022]
Abstract
The fig and pollinator wasp obligate mutualism is diverse (∼750 described species), ecologically important, and ancient (∼80 Ma). Once thought to be an example of strict one-to-one cospeciation, current thinking suggests genera of pollinator wasps codiversify with corresponding sections of figs, but the degree to which cospeciation or other processes contribute to the association at finer scales is unclear. Here, we use genome-wide sequence data from a community of Panamanian strangler figs and associated wasp pollinators to estimate the relative contributions of four evolutionary processes generating cophylogenetic patterns in this mutualism: cospeciation, host switching, pollinator speciation, and pollinator extinction. Using a model-based approach adapted from the study of gene family evolution, our results demonstrate the importance of host switching of pollinator wasps at this fine phylogenetic and regional scale. Although we estimate a modest amount of cospeciation, simulations reveal the number of putative cospeciation events to be consistent with what would be expected by chance. Additionally, model selection tests identify host switching as a critical parameter for explaining cophylogenetic patterns in this system. Our study demonstrates a promising approach through which the history of evolutionary association between interacting lineages can be rigorously modeled and tested in a probabilistic phylogenetic framework.
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Affiliation(s)
- Jordan D Satler
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, 50011
| | - Edward Allen Herre
- Smithsonian Tropical Research Institute, Unit 9100, P.O. Box 0498, Diplomatic Post Office, Armed Forces America 34002-9998
| | - K Charlotte Jandér
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, 752 36, Uppsala, Sweden
| | - Deren A R Eaton
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, New York, 10027
| | - Carlos A Machado
- Department of Biology, University of Maryland, College Park, Maryland, 20742
| | - Tracy A Heath
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, 50011
| | - John D Nason
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, 50011
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24
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Yu H, Tian E, Zheng L, Deng X, Cheng Y, Chen L, Wu W, Tanming W, Zhang D, Compton SG, Kjellberg F. Multiple parapatric pollinators have radiated across a continental fig tree displaying clinal genetic variation. Mol Ecol 2019; 28:2391-2405. [DOI: 10.1111/mec.15046] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 01/31/2019] [Accepted: 02/01/2019] [Indexed: 12/18/2022]
Affiliation(s)
- Hui Yu
- Guangdong Provincial Key Laboratory of Digital Botanical Garden and Key Laboratory of Plant Resource Conservation and Sustainable Utilization, South China Botanical Garden The Chinese Academy of Sciences Guangzhou China
- Centre for Plant Ecology, CAS Core Botanical Gardens Guangzhou China
| | - Enwei Tian
- Guangdong Provincial Key Laboratory of Digital Botanical Garden and Key Laboratory of Plant Resource Conservation and Sustainable Utilization, South China Botanical Garden The Chinese Academy of Sciences Guangzhou China
| | - Linna Zheng
- Guangdong Provincial Key Laboratory of Digital Botanical Garden and Key Laboratory of Plant Resource Conservation and Sustainable Utilization, South China Botanical Garden The Chinese Academy of Sciences Guangzhou China
| | - Xiaoxia Deng
- Guangdong Provincial Key Laboratory of Digital Botanical Garden and Key Laboratory of Plant Resource Conservation and Sustainable Utilization, South China Botanical Garden The Chinese Academy of Sciences Guangzhou China
| | - Yufen Cheng
- Guangdong Provincial Key Laboratory of Digital Botanical Garden and Key Laboratory of Plant Resource Conservation and Sustainable Utilization, South China Botanical Garden The Chinese Academy of Sciences Guangzhou China
| | - Lianfu Chen
- Guangdong Provincial Key Laboratory of Digital Botanical Garden and Key Laboratory of Plant Resource Conservation and Sustainable Utilization, South China Botanical Garden The Chinese Academy of Sciences Guangzhou China
| | - Wei Wu
- Guangdong Provincial Key Laboratory of Digital Botanical Garden and Key Laboratory of Plant Resource Conservation and Sustainable Utilization, South China Botanical Garden The Chinese Academy of Sciences Guangzhou China
| | | | - Dayong Zhang
- State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences Beijing Normal University Beijing China
| | | | - Finn Kjellberg
- CEFE, CNR, EPHE, IRD Université de Montpellier, Université Paul‐Valéry Montpellier Montpellier France
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Woodruff GC, Phillips PC. Field studies reveal a close relative of C. elegans thrives in the fresh figs of Ficus septica and disperses on its Ceratosolen pollinating wasps. BMC Ecol 2018; 18:26. [PMID: 30129423 PMCID: PMC6102938 DOI: 10.1186/s12898-018-0182-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 07/30/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Biotic interactions are ubiquitous and require information from ecology, evolutionary biology, and functional genetics in order to be understood. However, study systems that are amenable to investigations across such disparate fields are rare. Figs and fig wasps are a classic system for ecology and evolutionary biology with poor functional genetics; Caenorhabditis elegans is a classic system for functional genetics with poor ecology. In order to help bridge these disciplines, here we describe the natural history of a close relative of C. elegans, Caenorhabditis inopinata, that is associated with the fig Ficus septica and its pollinating Ceratosolen wasps. RESULTS To understand the natural context of fig-associated Caenorhabditis, fresh F. septica figs from four Okinawan islands were sampled, dissected, and observed under microscopy. C. inopinata was found in all islands where F. septica figs were found. C.i nopinata was routinely found in the fig interior and almost never observed on the outside surface. C. inopinata was only found in pollinated figs, and C. inopinata was more likely to be observed in figs with more foundress pollinating wasps. Actively reproducing C. inopinata dominated early phase figs, whereas late phase figs with emerging wasp progeny harbored C. inopinata dauer larvae. Additionally, C. inopinata was observed dismounting from Ceratosolen pollinating wasps that were placed on agar plates. C. inopinata was not found on non-pollinating, parasitic Philotrypesis wasps. Finally, C. inopinata was only observed in F. septica figs among five Okinawan Ficus species sampled. CONCLUSION These are the first detailed field observations of C. inopinata, and they suggest a natural history where this species proliferates in early phase F. septica figs and disperses from late phase figs on Ceratosolen pollinating fig wasps. While consistent with other examples of nematode diversification in the fig microcosm, the fig and wasp host specificity of C. inopinata is highly divergent from the life histories of its close relatives and frames hypotheses for future investigations. This natural co-occurrence of the fig/fig wasp and C. inopinata study systems sets the stage for an integrated research program that can help to explain the evolution of interspecific interactions.
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Affiliation(s)
- Gavin C Woodruff
- Forest Pathology Laboratory, Forestry and Forest Products Research Institute, Tsukuba, Japan.
- Department of Biology, Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA.
| | - Patrick C Phillips
- Department of Biology, Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA
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Segar ST, Mardiastuti A, Wheeler PM, Cook JM. Detecting the elusive cost of parasites on fig seed production. ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY 2018. [DOI: 10.1016/j.actao.2018.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Wang R, Yang CH, Ding YY, Tong X, Chen XY. Weak genetic divergence suggests extensive gene flow at the northeastern range limit of a dioecious Ficus species. ACTA OECOLOGICA 2018. [DOI: 10.1016/j.actao.2018.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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