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Suetsugu K, Hirota SK, Shitara T, Ishida K, Nakato N, Hayakawa H, Suyama Y. The absence of bumblebees on an oceanic island blurs the species boundary of two closely related orchids. THE NEW PHYTOLOGIST 2024; 241:1321-1333. [PMID: 37847353 DOI: 10.1111/nph.19325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/26/2023] [Indexed: 10/18/2023]
Abstract
Oceanic islands offer valuable natural laboratories for studying evolution. The Izu Islands, with their recent geological origin, provide an exceptional opportunity to explore the initial evolution on oceanic islands. Another noteworthy aspect is the absence of bumblebee species on most Izu Islands. We used ecological, morphological, and molecular data to investigate the impact of bumblebee absence on the evolution of two closely related orchid species, Goodyera henryi and Goodyera similis, focusing on Kozu Island, the Izu Islands. Our investigation revealed that while G. henryi exclusively relies on a bumblebee species for pollination on the mainland, G. similis is pollinated by scoliid wasps on both the mainland and the island. Intriguingly, all specimens initially categorized as G. henryi on Kozu Island are hybrids of G. henryi and G. similis, leading to the absence of pure G. henryi distribution on the island. These hybrids are pollinated by the scoliid wasp species that also pollinates G. similis on the island. The absence of bumblebees might result in sporadic and inefficient pollination of G. henryi by scoliid wasps, consequently promoting hybrid proliferation on the island. Our findings suggest that the absence of bumblebees can blur plant species boundaries.
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Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Hyogo, 657-8501, Japan
- Institute for Advanced Research, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Shun K Hirota
- Field Science Center, Graduate School of Agricultural Science, Tohoku University, 232-3 Yomogida, Naruko-onsen, Osaki, Miyagi, 989-6711, Japan
- Botanical Gardens, Osaka Metropolitan University, 2000 Kisaichi, Katano City, Osaka, 576-0004, Japan
| | - Takuto Shitara
- Tama Forest Science Garden, Forestry and Forest Products Research Institute, 1833-81 Todori-machi, Hachioji, Tokyo, 193-0843, Japan
| | | | - Narumi Nakato
- Narahashi 1-363, Higashiyamato-shi, Tokyo, 207-0031, Japan
| | - Hiroshi Hayakawa
- Museum of Natural and Environmental History, Shizuoka, 5762 Oya, Suruga, Shizuoka, Shizuoka, 422-8017, Japan
| | - Yoshihisa Suyama
- Field Science Center, Graduate School of Agricultural Science, Tohoku University, 232-3 Yomogida, Naruko-onsen, Osaki, Miyagi, 989-6711, Japan
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A symbiotic aphid selfishly manipulates attending ants via dopamine in honeydew. Sci Rep 2021; 11:18569. [PMID: 34535706 PMCID: PMC8448758 DOI: 10.1038/s41598-021-97666-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 08/25/2021] [Indexed: 11/08/2022] Open
Abstract
Symbiotic relationships are widespread in nature, but the mechanisms maintaining these relationships remain to be elucidated because symbiosis incurs a maintenance cost to each participant, which lowers its reproductive rate. In host-parasite relationships, parasites are known to manipulate the host's behavior selfishly, and there is an arms race between them. Selfish manipulations also occur in symbiosis, but the effects of selfish manipulations on symbiosis are not fully understood. Here, we show that an ant-associated aphid manipulates attending ants to receive stronger protection. Aphid honeydew regurgitated by ants contains dopamine (DA). The ants showed low aggressiveness before contact with the aphids, but it rose after contact. Administration of DA to the ants increased ant aggressiveness as the concentration increased, while an antagonist of DA inhibited this effect. The other 3 amines showed no effect on aggressiveness. A previous study showed that attending ants selfishly manipulate aphids by increasing the reproductive rate of green morph to obtain high-quality honeydew. These results suggest that mutual selfish manipulation benefits both participants and is likely to strengthen symbiosis. The selfishness of each participant may contribute to sustaining this symbiosis because their selfishness increases their long-term fitness.
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Williams MA, Holland CV, Donohue I. Warming can alter host behavior in a similar manner to infection with behavior-manipulating parasites. Oecologia 2020; 194:65-74. [PMID: 32876762 DOI: 10.1007/s00442-020-04745-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 08/26/2020] [Indexed: 11/29/2022]
Abstract
Parasites are ecologically ubiquitous and, by modifying the physiology and behavior of their host organisms, act as key regulators of the dynamics and stability of ecosystems. It is, however, as yet unclear how parasitic relationships will act to moderate or accelerate the ecological impacts of global climate change. Here, we explore experimentally how the effects of parasites on both the physiology and behavior of their hosts can be moderated by warming, utilising a well-established aquatic host-parasite model system-the ecologically important amphipod Gammarus duebeni and its acanthocephalan parasite Polymorphus minutus. We show that, while only warming affected measured components of host physiology, parasite infection and warming both supressed predator-avoidance behavior of the host independently, yet in a similar manner. Six degrees of warming altered geotactic behaviors to the same extent as infection with behavior-manipulating parasites. These results indicate a novel mechanism by which parasites impact their ecosystems that could be critical to predicting the ecological impacts of warming. Our findings highlight the need for holistic knowledge of interaction networks, incorporating multiple interaction types and behaviors, to predict the effects of both warming and parasitism on the dynamics and stability of ecosystems.
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Affiliation(s)
- Maureen A Williams
- Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Dublin 2, Ireland. .,School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, USA.
| | - Celia V Holland
- Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Dublin 2, Ireland
| | - Ian Donohue
- Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Dublin 2, Ireland
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Colgan TJ, Carolan JC, Sumner S, Blaxter ML, Brown MJF. Infection by the castrating parasitic nematode Sphaerularia bombi changes gene expression in Bombus terrestris bumblebee queens. INSECT MOLECULAR BIOLOGY 2020; 29:170-182. [PMID: 31566835 DOI: 10.1111/imb.12618] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 08/20/2019] [Accepted: 09/13/2019] [Indexed: 06/10/2023]
Abstract
Parasitism can result in dramatic changes in host phenotype, which are themselves underpinned by genes and their expression. Understanding how hosts respond at the molecular level to parasites can therefore reveal the molecular architecture of an altered host phenotype. The entomoparasitic nematode Sphaerularia bombi is a parasite of bumblebee (Bombus) hosts where it induces complex behavioural changes and host castration. To examine this interaction at the molecular level, we performed genome-wide transcriptional profiling using RNA-Sequencing (RNA-Seq) of S. bombi-infected Bombus terrestris queens at two critical time-points: during and just after overwintering diapause. We found that infection by S. bombi affects the transcription of genes underlying host biological processes associated with energy usage, translation, and circadian rhythm. We also found that the parasite affects the expression of immune genes, including members of the Toll signalling pathway providing evidence for a novel interaction between the parasite and the host immune response. Taken together, our results identify host biological processes and genes affected by an entomoparasitic nematode providing the first steps towards a molecular understanding of this ecologically important host-parasite interaction.
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Affiliation(s)
- T J Colgan
- Department of Zoology, School of Natural Sciences, University of Dublin, Trinity College, Dublin, Ireland
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland
| | - J C Carolan
- Department of Biology, Maynooth University, Maynooth, County Kildare, Ireland
| | - S Sumner
- Centre for Biodiversity and Environment Research, University College London, London, UK
| | - M L Blaxter
- School of Biological Sciences, Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | - M J F Brown
- Centre of Ecology, Evolution and Behaviour, Department of Biological Sciences, Royal Holloway University of London, Egham, UK
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Hiraiwa MK, Ushimaru A. Low functional diversity promotes niche changes in natural island pollinator communities. Proc Biol Sci 2017; 284:rspb.2016.2218. [PMID: 28077773 DOI: 10.1098/rspb.2016.2218] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 11/29/2016] [Indexed: 11/12/2022] Open
Abstract
Functional diversity loss among pollinators has rapidly progressed across the globe and is expected to influence plant-pollinator interactions in natural communities. Although recent findings suggest that the disappearance of a certain pollinator functional group may cause niche expansions and/or shifts in other groups, no study has examined this prediction in natural communities with high plant and pollinator diversities. By comparing coastal pollination networks on continental and oceanic islands, we examined how community-level flower visit patterns are influenced by the relative biomass of long-tongued pollinators (RBLP). We found that RBLP significantly correlated with pollinator functional diversity and was lower in oceanic than in continental islands. Pollinator niches shifted with decreasing RBLP, such that diverse species with various proboscis lengths, especially short-tongued species, increasingly visited long-tubed flowers. However, we found no conspicuous negative impacts of low RBLP and the consequent niche shifts on pollinator visit frequencies to flowers in oceanic island communities. Notably, fruit set significantly decreased as RBLP decreased in a study plant species. These results suggest that niche shifts by other functional groups can generally compensate for a decline in long-tongued pollinators in natural communities, but there may be negative impacts on plant reproduction.
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Affiliation(s)
- Masayoshi K Hiraiwa
- Graduate School of Human Development and Environment, Kobe University, Kobe 657-8501, Japan
| | - Atushi Ushimaru
- Graduate School of Human Development and Environment, Kobe University, Kobe 657-8501, Japan
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Legitimate visitors and nectar robbers on Trifolium pratense showed contrasting flower fidelity versus co-flowering plant species: could motor learning be a major determinant of flower constancy by bumble bees? Behav Ecol Sociobiol 2016. [DOI: 10.1007/s00265-016-2057-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Takasuka K, Yasui T, Ishigami T, Nakata K, Matsumoto R, Ikeda K, Maeto K. Host manipulation by an ichneumonid spider ectoparasitoid that takes advantage of preprogrammed web-building behaviour for its cocoon protection. J Exp Biol 2015; 218:2326-32. [DOI: 10.1242/jeb.122739] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
ABSTRACT
Host manipulation by parasites and parasitoids is a fascinating phenomenon within evolutionary ecology, representing an example of extended phenotypes. To elucidate the mechanism of host manipulation, revealing the origin and function of the invoked actions is essential. Our study focused on the ichneumonid spider ectoparasitoid Reclinervellus nielseni, which turns its host spider (Cyclosa argenteoalba) into a drugged navvy, to modify the web structure into a more persistent cocoon web so that the wasp can pupate safely on this web after the spider's death. We focused on whether the cocoon web originated from the resting web that an unparasitized spider builds before moulting, by comparing web structures, building behaviour and silk spectral/tensile properties. We found that both resting and cocoon webs have reduced numbers of radii decorated by numerous fibrous threads and specific decorating behaviour was identical, suggesting that the cocoon web in this system has roots in the innate resting web and ecdysteroid-related components may be responsible for the manipulation. We also show that these decorations reflect UV light, possibly to prevent damage by flying web-destroyers such as birds or large insects. Furthermore, the tensile test revealed that the spider is induced to repeat certain behavioural steps in addition to resting web construction so that many more threads are laid down for web reinforcement.
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Affiliation(s)
- Keizo Takasuka
- Laboratory of Insect Biodiversity and Ecosystem Science, Graduate School of Agricultural Science, Kobe University, Hyogo 657-8501, Japan
| | - Tomoki Yasui
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Hyogo 657-8501, Japan
| | - Toru Ishigami
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Hyogo 657-8501, Japan
| | - Kensuke Nakata
- Faculty for the Study of Contemporary Society, Kyoto Women's University, Kyoto 605-8501, Japan
| | | | - Kenichi Ikeda
- Laboratory of Stress Cytology, Graduate School of Agricultural Science, Kobe University, Hyogo 657-8501, Japan
| | - Kaoru Maeto
- Laboratory of Insect Biodiversity and Ecosystem Science, Graduate School of Agricultural Science, Kobe University, Hyogo 657-8501, Japan
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