1
|
Nishida S, Tamakoshi N, Takakura KI, Watanabe Y, Kanaoka MM. Reproductive interference between alien species in Veronica. JOURNAL OF PLANT RESEARCH 2024; 137:167-178. [PMID: 38108991 DOI: 10.1007/s10265-023-01510-3] [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: 06/02/2023] [Accepted: 11/17/2023] [Indexed: 12/19/2023]
Abstract
Reproductive interference can lead to the exclusive distribution of species. Reports on reproductive interference between alien species are scarce, although alien species are becoming more abundant and evaluations of the interference between aliens and its influence on community structure are essential. We therefore investigated the presence of interference in two alien species of Veronica, V. cymbalaria and V. persica. Hand-pollination experiments revealed that heterospecific pollen adversely affected both species, but asymmetrically: in V. cymbalaria, it reduced the number of seeds both before and after conspecific pollination, but in V. persica it reduced the number of seeds only when it occurred before conspecific pollination. Field observation suggested that the number of seeds produced by V. cymbalaria was more influenced by the number of conspecific flowers than by the frequency of surrounding V. persica flowers. Pot experiments did not show a negative effect of heterospecific individuals on the reproductive success of focal species in either species. Observations of visiting pollinators revealed no pollinator preference between the plant species. Although we demonstrated asymmetrical reproductive interference between V. cymbalaria and V. persica, its effect in the field seemed limited. An essential factor mitigating the adverse effect of reproductive interference might be a shortage of pollinators that could facilitate interspecific pollination. We predict that further invasion of V. cymbalaria into areas where V. persica prevails is unlikely, although swift displacement of V. cymbalaria by V. persica in areas where V. cymbalaria is already established is also unlikely.
Collapse
Affiliation(s)
- Sachiko Nishida
- Graduate School of Environmental Studies, Nagoya University, Furo‑cho, Chikusa‑ku, Nagoya, 464‑8601, Japan.
- Nagoya University Museum, Furo‑cho, Chikusa‑ku, Nagoya, 464‑8601, Japan.
| | - Naoko Tamakoshi
- Graduate School of Environmental Studies, Nagoya University, Furo‑cho, Chikusa‑ku, Nagoya, 464‑8601, Japan
| | - Ko-Ichi Takakura
- School of Environmental Science, The University of Shiga Prefecture, Yasaka‑cho, Hikone, 552‑0057, Japan
| | - Yuta Watanabe
- Graduate School of Environmental Studies, Nagoya University, Furo‑cho, Chikusa‑ku, Nagoya, 464‑8601, Japan
| | - Masahiro M Kanaoka
- Graduate School of Science, Nagoya University, Furo‑cho, Chikusa‑ku, Nagoya, 464‑8601, Japan
- Faculty of Bioresource Sciences, Prefectural University of Hiroshima, Nanatsuka-Cho, Shobara, 727-0023, Japan
| |
Collapse
|
2
|
Saji S, Yamasaki K, Fujimoto N, Naka H. Behavioral Comparison in Males of Two Praying Mantis Species of the Same Genus, Hierodula patellifera and H. chinensis (Mantodea: Mantidae: Hierodulinae) in Japan, in Response to the Conspecific or Allospecific Species of Calling Females and Females' Headspace Crude Extract. ENVIRONMENTAL ENTOMOLOGY 2022; 51:885-891. [PMID: 36130336 DOI: 10.1093/ee/nvac070] [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: 12/20/2021] [Indexed: 06/15/2023]
Abstract
For many years, only one species of praying mantis in the genus Hierodula, Hierodula patellifera Serville, had been recorded in Japan. In recent years, however, Hierodula chinensis Werner, a larger species than H. patellifera Serville, has been discovered in Japan, and observations and collections in Japan have increased rapidly. There are reports that in some areas, H. patellifera became locally extinct due to the invasion of H. chinensis. Since females of H. patellifera attract conspecific males by volatile with characteristic calling behavior, a sex pheromone-mediated reproductive interference may exist between the two species. Both males of H. patellifera and males of H. chinensis were strongly attracted to conspecific females and crude headspace extract from conspecific females, while they were not attracted to females of allospecific species or crude headspace extract from allospecific females. These results indicate that sex pheromone-mediated reproductive interference may not exist between H. patellifera and H. chinensis.
Collapse
Affiliation(s)
- Seiya Saji
- Laboratory of Applied Entomology, Faculty of Agriculture, Tottori University, Koyama-Minami 4-101, Tottori, Tottori 680-8553, Japan
| | - Kazuhisa Yamasaki
- Institute for Sustainable Agro-ecosystem Services, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Midori-cho, Nishitokyo, Tokyo 188-0002, Japan
- Faculty of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Nanami Fujimoto
- Laboratory of Applied Entomology, Faculty of Agriculture, Tottori University, Koyama-Minami 4-101, Tottori, Tottori 680-8553, Japan
| | - Hideshi Naka
- Laboratory of Applied Entomology, Faculty of Agriculture, Tottori University, Koyama-Minami 4-101, Tottori, Tottori 680-8553, Japan
| |
Collapse
|
3
|
Hashimoto K, Yamamoto A, Kanaoka MM, Naiki A, Takakura KI, Nishida S. Comparisons among populations and individuals to evaluate pollen-pistil interaction as a mechanism of reproductive interference in Taraxacum. JOURNAL OF PLANT RESEARCH 2022; 135:29-40. [PMID: 34609645 DOI: 10.1007/s10265-021-01352-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 09/29/2021] [Indexed: 06/13/2023]
Abstract
Reproductive interference (RI), an interspecific mating interaction that reduces the fitness of at least one of the species involved, can lead to exclusive distributions in closely related species. A hypothesis previously proposed is that RI in plants may occur by ovule usurpation, in which pistils lack interspecific incompatibility and mistakenly accept heterospecific pollen, thereby losing an opportunity for conspecific pollen fertilization. However, few comparative studies have evaluated the consistency of the inferred mechanism within and among individuals and populations. We conducted hand-pollination experiments in six populations of three native Taraxacum species that suffered from different levels of RI from an alien congener, T. officinale, and compared pollen-pistil interactions among populations. We also investigated the interactions for eight individual T. japonicum plants whose response to heterospecific pollen deposition had been previously measured. Our results revealed that pollen tubes often penetrated native ovaries following heterospecific pollination in populations suffering from strong RI, whereas they seldom did in populations suffering from marginal RI. However, the relative frequency of the pollen tube penetration was not significantly related to the strength of alien RI. Not all pistils on an individual plant showed the same pollen receptivity following heterospecific pollination; rather, some accepted and some refused the pollen tubes. The relationship between pollen tube penetration following heterospecific pollination and the strength of the alien RI was also not significant among individuals. Our present results generally support the ovule usurpation hypothesis, but suggest that other factors, such as competition for pollinator services, variation in the effects of heterospecific pollen donors, and condition of the native inflorescences, might also affect the observed RI strength.
Collapse
Affiliation(s)
- Keisuke Hashimoto
- Graduate School of Environmental Studies, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
| | - Akane Yamamoto
- Graduate School of Education, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama, 700-8530, Japan
| | - Masahiro M Kanaoka
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
| | - Akiyo Naiki
- Iriomote Station, Tropical Biosphere Research Center, University of the Ryukyus, Taketomi-cho, Yaeyama, 907-1541, Japan
| | - Ko-Ichi Takakura
- School of Environmental Science, The University of Shiga Prefecture, Yasaka-cho, Hikone, 552-0057, Japan
| | - Sachiko Nishida
- Graduate School of Environmental Studies, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan.
- Nagoya University Museum, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan.
| |
Collapse
|
4
|
Ohsaki N, Ohata M, Sato Y, Rausher MD. Host Plant Choice Determined by Reproductive Interference between Closely Related Butterflies. Am Nat 2020; 196:512-523. [PMID: 32970464 DOI: 10.1086/710211] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractA number of empirical studies have concluded that reproductive interference (RI) contributes to parapatric species distributions or sexual exclusion. However, the possibility that divergent host plant use in phytophagous insects is due to sexual exclusion has seldom been considered. Here, we present evidence that RI is responsible for different host plant use by two Pierid butterfly species, Pieris napi and Pieris melete. When a novel host species was introduced about 50 years ago, two Pierid butterfly species at first used both the ancestral host species and the novel one. Subsequently, P. napi shifted to use only the novel host, while P. melete shifted to specialize on the ancestral host. To explain these patterns, we investigated whether the two host species differ in suitability for larval growth and survival. Additionally, we tested whether RI occurred between the two butterfly species using large outdoor field cages. Courtship of females by conspecific and heterospecific males reduces the number of eggs laid by approximately half. However, RI is asymmetric and would generate selection on P. melete females to evolve to avoid the more suitable host species preferred by P. napi. Thus, our study suggests that sexual exclusion can explain the shift in host plant use by these two butterfly species.
Collapse
|
5
|
Nishida S, Takakura KI, Naiki A, Nishida T. Habitat partitioning in native Geranium species through reproductive interference. ANNALS OF BOTANY 2020; 125:651-661. [PMID: 31900487 PMCID: PMC7102965 DOI: 10.1093/aob/mcz210] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 12/30/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND AIMS Heterospecific pollen transfer may reduce the fitness of recipient species, a phenomenon known as reproductive interference. A theoretical study has predicted that distributions of species pairs affected by reproductive interference may be syntopic under negligible reproductive interference, sympatric but with partitioning at small spatial scale (i.e. allotopic) under weak interference, or exclusive when reproductive interference is strong. Verifying these predictions is essential for evaluation of the applicability of reproductive interference as a general assembly rule of biological communities. The aim of this study was to test these predictions in two sympatrically distributed wild Geranium species, G. thunbergii and G. wilfordii. METHODS To measure the effect of reproductive interference, the associations between the relative abundance of the counterpart species and seed set in the focal species, and seed set reduction following mixed pollination, were analysed. The possibility of hybridization with viable offspring was examined by genotyping plants in the field and after mixed pollination. Fertility of putative hybrids was based on their seed set and the proportion of pollen grains with apertural protrusions. A transect study was conducted to examine spatial partitioning, and possible influences of environmental conditions (canopy openness and soil moisture content) on partitioning between the species were analysed. KEY RESULTS Neither abundance of the counterpart species nor heterospecific pollen deposition significantly affected seed set in the focal species, and hybridization between species was almost symmetrical. Putative hybrids had low fertility. The two species were exclusively distributed at small scale, although environmental conditions were not significantly different between them. CONCLUSIONS The allotopy of the two species may be maintained by relatively weak reproductive interference through bidirectional hybridization. Re-evaluation of hybridization may allow ongoing or past reproductive interference to be recognized and provide insight into the distributional relationships between the interacting plants.
Collapse
Affiliation(s)
- Sachiko Nishida
- Nagoya University Museum, Furo-cho, Chikusa-ku, Nagoya, Japan
| | - Koh-Ichi Takakura
- School of Environmental Science, University of Shiga Prefecture, Yasaka-cho, Hikone, Japan
| | - Akiyo Naiki
- Iriomote Station, Tropical Biosphere Research Center, University of the Ryukyus, Taketomi-cho, Yaeyama-gun, Japan
| | - Takayoshi Nishida
- School of Environmental Science, University of Shiga Prefecture, Yasaka-cho, Hikone, Japan
| |
Collapse
|
6
|
Takemori A, Naiki A, Takakura KI, Kanaoka MM, Nishida S. Comparison of mechanisms of reproductive interference in Taraxacum. ANNALS OF BOTANY 2019; 123:1017-1027. [PMID: 30715137 PMCID: PMC6589510 DOI: 10.1093/aob/mcz007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 01/07/2019] [Indexed: 05/30/2023]
Abstract
BACKGROUND AND AIMS Reproductive interference may reduce fitness of either of the involved species, with potentially important ecological and evolutionary consequences. Except for the effect of shared pollinators on reproductive success, however, mechanisms underlying reproductive interference have been little studied, even though the severity of its impact may depend on the specific mechanism. The aim of this study was therefore to explore the mechanisms of reproductive interference between Taraxacum japonicum (native to Japan) and Taraxacum officinale (alien). METHODS In a field survey, the association between alien species density and seed set in T. japonicum, and whether pollinator behaviour indicated a preference for the alien, were examined. Effects of heterospecific pollen deposition were measured in a series of hand pollination experiments, including mixed pollination experiments in which the order of application of conspecific and heterospecific pollen was varied. Finally, to investigate hybridization frequency, the parentage of seedlings produced following natural, mixed or heterospecific pollination was compared. KEY RESULTS Alien species density did not negatively affect native seed set, nor did pollinators appear to have a preference for alien flowers. The hand pollination experiments showed that heterospecific pollen deposition adversely affected native seed set, especially when alien pollen was applied before conspecific pollen. No viable hybrids were found following natural pollination, which suggests that hybridization might be a rare event. CONCLUSION Among the examined mechanisms, heterospecific pollen deposition might have the largest deleterious effect on the native species. This effect is frequency dependent; thus, a positive feedback loop may cause the effect on the population dynamics to increase over time, with the result that the alien might eventually displace the native in a population. Effects of the examined mechanisms on population dynamics should be investigated further to improve understanding of the impact of reproductive interference on the structure of plant communities.
Collapse
Affiliation(s)
- Akane Takemori
- Graduate School of Education, Okayama University, Kita-ku, Okayama City, Japan
| | - Akiyo Naiki
- Iriomote Station, Tropical Biosphere Research Center, University of the Ryukyus, Yaeyama-gun, Japan
| | - Ko-Ichi Takakura
- School of Environmental Science, The University of Shiga Prefecture, Hikone, Japan
| | - Masahiro M Kanaoka
- Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan
| | | |
Collapse
|
7
|
Katsuhara KR, Ushimaru A. Prior selfing can mitigate the negative effects of mutual reproductive interference between coexisting congeners. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13344] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Koki R. Katsuhara
- Graduate School of Human Development and Environment Kobe University Kobe Japan
| | - Atushi Ushimaru
- Graduate School of Human Development and Environment Kobe University Kobe Japan
| |
Collapse
|
8
|
Clemente SH, Santos I, Ponce R, Rodrigues LR, Varela SAM, Magalhães S. Despite reproductive interference, the net outcome of reproductive interactions among spider mite species is not necessarily costly. Behav Ecol 2017. [DOI: 10.1093/beheco/arx161] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Salomé H Clemente
- cE3c – Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
| | - Inês Santos
- cE3c – Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
| | - Rita Ponce
- cE3c – Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
- ESS/IPS – School of Health, Polytechnic Institute of Setubal, Setubal, Portugal
| | - Leonor R Rodrigues
- cE3c – Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
| | - Susana A M Varela
- cE3c – Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
- IGC – Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Sara Magalhães
- cE3c – Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
| |
Collapse
|
9
|
Wu FY, Yahara T. Recurved Taraxacum phyllaries function as a floral defense: experimental evidence and its implication for Taraxacum evolutionary history. Ecol Res 2017. [DOI: 10.1007/s11284-017-1444-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
10
|
Nishida S, Hashimoto K, Kanaoka MM, Takakura KI, Nishida T. Variation in the strength of reproductive interference from an alien congener to a native species in Taraxacum. JOURNAL OF PLANT RESEARCH 2017; 130:125-134. [PMID: 27659681 DOI: 10.1007/s10265-016-0865-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 08/08/2016] [Indexed: 06/06/2023]
Abstract
Reproductive interference (RI) may be a contributing factor to the displacement of native species by an alien congener, and RI strength has been shown theoretically to affect distributional relationships between species. Thus, variations in RI strength from alien to native species result in different consequences of invasions and efforts to conserve native species, but the variations have seldom been examined empirically. We therefore investigated RI strength variations from the alien species Taraxacum officinale and its hybrids to eight populations of native dandelions, four T. japonicum populations and two populations each of two subspecies of T. platycarpum. We examined the association between alien relative abundance and native seed set in field surveys, and we also performed hand-pollination experiments to investigate directly the sensitivity of native flowers to alien pollen. We found that the effect of alien relative abundance on native seed set of even the same native species could differ greatly in different regions, and that the sensitivity of native flowers to alien pollen was also dependent on region. Our results, together with those of previous studies, show that RI from the alien to the native species is strong in regions where the alien species outnumbers the native species and marginal where it does not; this result suggests that alien RI can critically affect distributional relationships between native and alien species. Our study highlights the importance of performing additional empirical investigations of RI strength variation and of giving due attention to alien RI in efforts to conserve regional native biodiversity.
Collapse
Affiliation(s)
- Sachiko Nishida
- Graduate School of Environmental Studies, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan.
- Nagoya University Museum, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan.
| | - Keisuke Hashimoto
- Graduate School of Environmental Studies, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
| | - Masahiro M Kanaoka
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
| | - Ko-Ichi Takakura
- School of Environmental Science, The University of Shiga Prefecture, Yasaka-cho, Hikone, 552-0057, Japan
| | - Takayoshi Nishida
- School of Environmental Science, The University of Shiga Prefecture, Yasaka-cho, Hikone, 552-0057, Japan
| |
Collapse
|
11
|
Spatial Distribution of Flower Color Induced by Interspecific Sexual Interaction. PLoS One 2016; 11:e0164381. [PMID: 27723785 PMCID: PMC5056732 DOI: 10.1371/journal.pone.0164381] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 09/23/2016] [Indexed: 11/19/2022] Open
Abstract
Understanding the mechanisms shaping the spatiotemporal distribution of species has long been a central concern of ecology and evolutionary biology. Contemporary patterns of plant assemblies suggest that sexual interactions among species, i.e., reproductive interference, lead to the exclusive distributions of closely related species that share pollinators. However, the fitness consequences and the initial ecological/evolutionary responses to reproductive interference remain unclear in nature, since reproductive isolation or allopatric distribution has already been achieved in the natural community. In Japan, three species of blue-eyed grasses (Sisyrinchium) with incomplete reproductive isolation have recently colonized and occur sympatrically. Two of them are monomorphic with white flowers, whereas the other exhibits heritable color polymorphism (white and purple morphs). Here we investigated the effects of the presence of two monomorphic species on the distribution and reproductive success of color morphs. The frequency and reproductive success of white morphs decreased in area where monomorphic species were abundant, while those of purple morphs did not. The rate of hybridization between species was higher in white morphs than in the purple ones. Resource competition and habitat preference seemed not to contribute to the spatial distribution and reproductive success of two morphs. Our results supported that color-dependent reproductive interference determines the distribution of flower color polymorphism in a habitat, implying ecological sorting promoted by pollinator-mediated reproductive interference. Our study helps us to understand the evolution and spatial structure of flower color in a community.
Collapse
|
12
|
Hersh E, Grimm J, Whitton J. Attack of the clones: reproductive interference between sexuals and asexuals in the Crepis agamic complex. Ecol Evol 2016; 6:6473-6483. [PMID: 27777723 PMCID: PMC5058521 DOI: 10.1002/ece3.2353] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 06/30/2016] [Accepted: 07/04/2016] [Indexed: 02/02/2023] Open
Abstract
Negative reproductive interactions are likely to be strongest between close relatives and may be important in limiting local coexistence. In plants, interspecific pollen flow is common between co-occurring close relatives and may serve as the key mechanism of reproductive interference. Agamic complexes, systems in which some populations reproduce through asexual seeds (apomixis), while others reproduce sexually, provide an opportunity to examine effects of reproductive interference in limiting coexistence. Apomictic populations experience little or no reproductive interference, because apomictic ovules cannot receive pollen from nearby sexuals. Oppositely, apomicts produce some viable pollen and can exert reproductive interference on sexuals by siring hybrids. In the Crepis agamic complex, sexuals co-occur less often with other members of the complex, but apomicts appear to freely co-occur with one another. We identified a mixed population and conducted a crossing experiment between sexual diploid C. atribarba and apomictic polyploid C. barbigera using pollen from sexual diploids and apomictic polyploids. Seed set was high for all treatments, and as predicted, diploid-diploid crosses produced all diploid offspring. Diploid-polyploid crosses, however, produced mainly polyploidy offspring, suggesting that non-diploid hybrids can be formed when the two taxa meet. Furthermore, a small proportion of seeds produced in open-pollinated flowers was also polyploid, indicating that polyploid hybrids are produced under natural conditions. Our results provide evidence for asymmetric reproductive interference, with pollen from polyploid apomicts contributing to reduce the recruitment of sexual diploids in subsequent generations. Existing models suggest that these mixed sexual-asexual populations are likely to be transient, eventually leading to eradication of sexual individuals from the population.
Collapse
Affiliation(s)
- Evan Hersh
- Department of Botany and Biodiversity Research CentreThe University of British Columbia6270 University BoulevardVancouverBritish ColumbiaCanadaV6T 1Z4
| | - Jaime Grimm
- Department of Botany and Biodiversity Research CentreThe University of British Columbia6270 University BoulevardVancouverBritish ColumbiaCanadaV6T 1Z4
- Present address: Department of BiologyMcGill University1205 Dr. Penfield AvenueMontrealQuébecCanadaH3A 1B1
| | - Jeannette Whitton
- Department of Botany and Biodiversity Research CentreThe University of British Columbia6270 University BoulevardVancouverBritish ColumbiaCanadaV6T 1Z4
| |
Collapse
|
13
|
Invasive conifers reduce seed set of a native Andean cedar through heterospecific pollination competition. Biol Invasions 2014. [DOI: 10.1007/s10530-014-0775-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
14
|
Liao SM, Kasuga S, Togashi K. Suppressive effects of Bursaphelenchus mucronatus on pine wilt disease development and mortality of B. xylophilus-inoculated pine seedlings. NEMATOLOGY 2014. [DOI: 10.1163/15685411-00002760] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Bursaphelenchus xylophilus causes pine wilt disease in Pinus trees whereas B. mucronatus has no or little virulence to the trees. Interspecific crossing experiments conducted so far suggest reproductive interference between the two nematode species. Theory predicts that one of the two competing species populations quickly displaces the other through reproductive interference in a frequency-dependent manner. Thus, it is anticipated that B. mucronatus suppresses the virulence of B. xylophilus against pine trees when B. mucronatus heavily outnumber B. xylophilus. To determine the suppressive effects of B. mucronatus, the two nematode species were inoculated simultaneously on 30 3-year-old Pinus thunbergii seedlings at three combinations of different numbers, and B. xylophilus alone was inoculated on 30 other seedlings at the corresponding numbers in early August. Seedlings were observed at intervals of 4 or 6 weeks and two stem sections were sampled from each seedling to determine the density and species composition of nematode populations after death or in December. Inoculation of B. mucronatus significantly retarded the speed of foliage discolouration from 0.170 ± 0.024 week−1 to 0.061 ± 0.017 week−1 and significantly prolonged the survival time of seedlings. Bursaphelenchus mucronatus significantly reduced the nematode density from 1799.7 ± 305.0 to 521.0 ± 148.4 (g dried seedling stem)−1. Analysis of rDNA genotype showed 1846 B xylophilus, no B. mucronatus and one hybrid.
Collapse
Affiliation(s)
- Si-Mi Liao
- Laboratory of Forest Zoology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Satomi Kasuga
- Laboratory of Forest Zoology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Katsumi Togashi
- Laboratory of Forest Zoology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| |
Collapse
|
15
|
Nishida S, Kanaoka MM, Hashimoto K, Takakura KI, Nishida T. Pollen-pistil interactions in reproductive interference: comparisons of heterospecific pollen tube growth from alien species between two nativeTaraxacumspecies. Funct Ecol 2013. [DOI: 10.1111/1365-2435.12165] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Keisuke Hashimoto
- Graduate School of Environmental Studies; Nagoya University; Nagoya 464-8601 Japan
| | - Koh-Ichi Takakura
- Osaka City Institute of Public Health and Environmental Science; Tennoji-ku Osaka 543-0026 Japan
| | - Takayoshi Nishida
- School of Environmental Science; The University of Shiga Prefecture; Hikone 522-0057 Japan
| |
Collapse
|