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Luna D, Mohanbabu N, Johnson J, Althoff DM. Host use by 2 sibling species of bogus yucca moths in relation to plant hardness and saponin content. Environ Entomol 2023; 52:659-666. [PMID: 37338184 DOI: 10.1093/ee/nvad054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/11/2023] [Accepted: 06/01/2023] [Indexed: 06/21/2023]
Abstract
Plant defenses allow plants to deter or kill their insect herbivores and are considered to be a major driver of host use for herbivorous insects in both ecological and evolutionary time. Many closely related species of insect herbivores differ in their ability to respond to plant defenses and in some cases are specialized to specific plant species. Here we tested whether both mechanical and chemical plant defenses are a major factor in determining the host range of 2 sibling species of Prodoxid bogus yucca moths, Prodoxus decipiens (Riley) and Prodoxus quinquepunctellus (Chambers) that feed within the inflorescence stalk of Yucca species. These 2 moth species have separate suites of host plant species, yet narrowly overlap geographically and share 1 Yucca species, Y. glauca. We surveyed the lignin and cellulose content, the force required to the puncture the stalk tissue, and saponin concentration across 5 Yucca species used as hosts. Lignin, cellulose concentrations, and stalk hardness differed among Yucca species but did not correlate with host use patterns by the moths. Saponin concentrations in the stalk tissue were relatively low for yuccas (<1%) and did not differ among species. The results suggest that these moth species should be able to use each other's hosts for egg deposition. Additional factors such as larval development or competition among larvae for feeding space may serve to keep moth species from expanding onto plants used by its sibling species.
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Affiliation(s)
- Diego Luna
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY 13244, USA
| | - Neha Mohanbabu
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY 13244, USA
- Department of Forest Resources, University of Minnesota, St. Paul, MN, USA
| | - Josiah Johnson
- Eugene P. Odum School of Ecology, University of Georgia, Athens, GA, USA
- Savannah River Ecology Laboratory, University of Georgia, Aikens, SC, USA
| | - David M Althoff
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY 13244, USA
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2
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Althoff DM, Segraves KA. Evolution of antagonistic and mutualistic traits in the yucca-yucca moth obligate pollination mutualism. J Evol Biol 2021; 35:100-108. [PMID: 34855267 DOI: 10.1111/jeb.13967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 11/30/2022]
Abstract
Species interactions shape the evolution of traits, life histories and the pattern of speciation. What is less clear is whether certain types of species interaction are more or less likely to lead to phenotypic divergence among species. We used the brood pollination mutualism between yuccas and yucca moths to test how mutualistic (pollination) and antagonistic (oviposition) traits differ in the propensity to increase phenotypic divergence among pollinator moths. We measured traits of the tentacular mouthparts, structures used by females to actively pollinate flowers, as well as ovipositor traits to examine differences in the rate of evolution of these two suites of traits among pollinator species. Morphological analyses revealed two distinct groups of moths based on ovipositor morphology, but no such groupings were identified for tentacle morphology, even for moths that pollinated distantly related yuccas. In addition, ovipositor traits evolved at significantly faster rates than tentacular traits. These results support theoretical work suggesting that antagonism is more likely than mutualism to lead to phenotypic divergence.
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Affiliation(s)
- David M Althoff
- Department of Biology, Syracuse University, Syracuse, New York, USA
| | - Kari A Segraves
- Department of Biology, Syracuse University, Syracuse, New York, USA
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3
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Vidal MC, Anneberg TJ, Curé AE, Althoff DM, Segraves KA. The variable effects of global change on insect mutualisms. Curr Opin Insect Sci 2021; 47:46-52. [PMID: 33771734 DOI: 10.1016/j.cois.2021.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/25/2021] [Accepted: 03/11/2021] [Indexed: 06/12/2023]
Abstract
Insect mutualisms are essential for reproduction of many plants, protection of plants and other insects, and provisioning of nutrients for insects. Disruption of these mutualisms by global change can have important implications for ecosystem processes. Here, we assess the general effects of global change on insect mutualisms, including the possible impacts on mutualistic networks. We find that the effects of global change on mutualisms are extremely variable, making broad patterns difficult to detect. We require studies focusing on changes in cost-benefit ratios, effects of partner dependency, and degree of specialization to further understand how global change will influence insect mutualism dynamics. We propose that rapid coevolution is one avenue by which mutualists can ameliorate the effects of global change.
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Affiliation(s)
- Mayra C Vidal
- Department of Biology, Syracuse University, Syracuse, NY 13210, USA; Biology Department, University of Massachusetts Boston, Boston, MA 02125, USA.
| | - Thomas J Anneberg
- Department of Biology, Syracuse University, Syracuse, NY 13210, USA; Biology Department, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Anne E Curé
- Department of Biology, Syracuse University, Syracuse, NY 13210, USA
| | - David M Althoff
- Department of Biology, Syracuse University, Syracuse, NY 13210, USA
| | - Kari A Segraves
- Department of Biology, Syracuse University, Syracuse, NY 13210, USA
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4
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Tröger A, Svensson GP, Galbrecht HM, Twele R, Patt JM, Bartram S, Zarbin PHG, Segraves KA, Althoff DM, von Reuss S, Raguso RA, Francke W. Tetranorsesquiterpenoids as Attractants of Yucca Moths to Yucca Flowers. J Chem Ecol 2021; 47:1025-1041. [PMID: 34506004 DOI: 10.1007/s10886-021-01308-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/01/2021] [Accepted: 08/23/2021] [Indexed: 11/30/2022]
Abstract
The obligate pollination mutualism between Yucca and yucca moths is a classical example of coevolution. Oviposition and active pollination by female yucca moths occur at night when Yucca flowers are open and strongly scented. Thus, floral volatiles have been suggested as key sensory signals attracting yucca moths to their host plants, but no bioactive compounds have yet been identified. In this study, we showed that both sexes of the pollinator moth Tegeticula yuccasella are attracted to the floral scent of the host Yucca filamentosa. Chemical analysis of the floral headspace from six Yucca species in sections Chaenocarpa and Sarcocarpa revealed a set of novel tetranorsesquiterpenoids putatively derived from (E)-4,8-dimethyl-1,3,7-nonatriene. Their structure elucidation was accomplished by NMR analysis of the crude floral scent sample of Yucca treculeana along with GC/MS analysis and confirmed by total synthesis. Since all these volatiles are included in the floral scent of Y. filamentosa, which has been an important model species for understanding the pollination mutualism, we name these compounds filamentolide, filamentol, filamental, and filamentone. Several of these compounds elicited antennal responses in pollinating (Tegeticula) and non-pollinating (Prodoxus) moth species upon stimulation in electrophysiological recordings. In addition, synthetic (Z)-filamentolide attracted significant numbers of both sexes of two associated Prodoxus species in a field trapping experiment. Highly specialized insect-plant interactions, such as obligate pollination mutualisms, are predicted to be maintained through "private channels" dictated by specific compounds. The identification of novel bioactive tetranorsesquiterpenoids is a first step in testing such a hypothesis in the Yucca-yucca moth interaction.
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Affiliation(s)
- Armin Tröger
- Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany
| | - Glenn P Svensson
- Department of Biology, Lund University, Solvegatan 37, 223 62, Lund, Sweden
| | - Hans-Martin Galbrecht
- Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany
| | - Robert Twele
- Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany
| | - Joseph M Patt
- USDA-Agricultural Research Service, U.S. Horticultural Research Laboratory, 2001 South Rock Road, Fort Pierce, FL, 34945, USA
| | - Stefan Bartram
- Department of Natural Product Biosynthesis, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745, Jena, Germany
| | - Paulo H G Zarbin
- Department of Chemistry, Federal University of Parana, Curitiba, PR, 81531-990, Brazil
| | - Kari A Segraves
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - David M Althoff
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Stephan von Reuss
- Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany.,Laboratory of Bioanalytical Chemistry, University of Neuchatel, Avenue de Bellevaux 51, CH-2000, Neuchatel, Switzerland
| | - Robert A Raguso
- Department of Neurobiology and Behavior, Cornell University, 215 Tower Road, Ithaca, NY, 14853, USA.
| | - Wittko Francke
- Institute of Organic Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany
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5
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Vidal MC, Wang SP, Rivers DM, Althoff DM, Segraves KA. Species richness and redundancy promote persistence of exploited
mutualisms in yeast. Science 2020; 370:346-350. [DOI: 10.1126/science.abb6703] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 06/26/2020] [Accepted: 08/26/2020] [Indexed: 01/21/2023]
Abstract
Mutualisms, or reciprocally beneficial interspecific interactions,
constitute the foundation of many ecological communities and agricultural
systems. Mutualisms come in different forms, from pairwise interactions to
extremely diverse communities, and they are continually challenged with
exploitation by nonmutualistic community members (exploiters). Thus,
understanding how mutualisms persist remains an essential question in
ecology. Theory suggests that high species richness and functional
redundancy could promote mutualism persistence in complex mutualistic
communities. Using a yeast system (Saccharomyces
cerevisiae), we experimentally show that communities with
the greatest mutualist richness and functional redundancy are nearly two
times more likely to survive exploitation than are simple communities.
Persistence increased because diverse communities were better able to
mitigate the negative effects of competition with exploiters. Thus, large
mutualistic networks may be inherently buffered from exploitation.
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Affiliation(s)
- Mayra C. Vidal
- Department of Biology, Syracuse University, Syracuse, NY 13210, USA
- Biology Department, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Sheng Pei Wang
- Department of Biology, Syracuse University, Syracuse, NY 13210, USA
| | | | - David M. Althoff
- Department of Biology, Syracuse University, Syracuse, NY 13210, USA
| | - Kari A. Segraves
- Department of Biology, Syracuse University, Syracuse, NY 13210, USA
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6
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Pellmyr O, Kjellberg F, Herre EA, Kawakita A, Hembry DH, Holland JN, Terrazas T, Clement W, Segraves KA, Althoff DM. Active pollination drives selection for reduced pollen-ovule ratios. Am J Bot 2020; 107:164-170. [PMID: 31889299 DOI: 10.1002/ajb2.1412] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
PREMISE Variation in pollen-ovule ratios is thought to reflect the degree of pollen transfer efficiency-the more efficient the process, the fewer pollen grains needed. Few studies have directly examined the relationship between pollen-ovule ratio and pollen transfer efficiency. For active pollination in the pollination brood mutualisms of yuccas and yucca moths, figs and fig wasps, senita and senita moths, and leafflowers and leafflower moths, pollinators purposefully collect pollen and place it directly on the stigmatic surface of conspecific flowers. The tight coupling of insect reproductive interests with pollination of the flowers in which larvae develop ensures that pollination is highly efficient. METHODS We used the multiple evolutionary transitions between passive pollination and more efficient active pollination to test if increased pollen transfer efficiency leads to reduced pollen-ovule ratios. We collected pollen and ovule data from a suite of plant species from each of the pollination brood mutualisms and used phylogenetically controlled tests and sister-group comparisons to examine whether the shift to active pollination resulted in reduced pollen-ovule ratios. RESULTS Across all transitions between passive and active pollination in plants, actively pollinated plants had significantly lower pollen-ovule ratios than closely related passively pollinated taxa. Phylogenetically corrected comparisons demonstrated that actively pollinated plant species had an average 76% reduction in the pollen-ovule ratio. CONCLUSIONS The results for active pollination systems support the general utility of pollen-ovule ratios as indicators of pollination efficiency and the central importance of pollen transfer efficiency in the evolution of pollen-ovule ratio.
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Affiliation(s)
- Olle Pellmyr
- Department of Biology, University of Idaho, Moscow, Idaho, 83844, USA
| | - Finn Kjellberg
- CEFE, CNRS, Université Montpellier, Université Paul Valéry Montpellier, EPHE, IRD, Montpellier, Cédex 5, France
| | - Edward Allen Herre
- Smithsonian Tropical Research Institute, Apartado Postal, 0843-03092, Panamá, Republic of Panama
| | - Atsushi Kawakita
- The Botanical Gardens, Graduate School of Science, University of Tokyo, 3-7-1 Hakusan, Bonkyo-ku, Tokyo, Japan
| | - David H Hembry
- Department of Entomology, Cornell University, 2130 Comstock Hall, Ithaca, New York, 14853, USA
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, 85721, USA
| | - J Nathaniel Holland
- School of Dentistry, University of Texas, 7500 Cambridge Street, Houston, Texas, 77054, USA
| | - Teresa Terrazas
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico
| | - Wendy Clement
- Department of Biology, The College of New Jersey, 2000 Pennington Road, Ewing, New Jersey, 08628, USA
| | - Kari A Segraves
- Department of Biology, Syracuse University, 107 College Place, Syracuse, New York, 13244, USA
| | - David M Althoff
- Department of Biology, Syracuse University, 107 College Place, Syracuse, New York, 13244, USA
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7
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Santos M, Matos M, Wang SP, Althoff DM. Selection on structural allelic variation biases plasticity estimates. Evolution 2019; 73:1057-1062. [PMID: 30874299 DOI: 10.1111/evo.13723] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 02/19/2019] [Accepted: 02/19/2019] [Indexed: 11/30/2022]
Abstract
Wang and Althoff (2019) explored the capacity of Drosophila melanogaster to exhibit adaptive plasticity in a novel environment. In a full-sib, half-sib design, they scored the activity of the enzyme alcohol dehydrogenase (ADH) and plastic responses, measured as changes in ADH activity across ethanol concentrations in the range of 0-10% (natural variation) and 16% (the novel environment). ADH activity increased with alcohol concentration, and there was a positive association between larval viability and ADH activity in the novel environment. They also reported that families exhibiting greater plasticity had higher larval survival in the novel environment, concluding that ADH plasticity is adaptive. However, the four authors now concur that, since the study estimated plasticity from phenotypic differences across environments using full-sib families, it is not possible to disentangle the contributions of allele frequency changes at the Adh locus from regulatory control at loci known to influence ADH activity. Selective changes in allele frequencies may thus conflate estimates of plasticity; any type of "plasticity" (adaptive, neutral, or maladaptive) could be inferred depending on allele frequencies. The problem of scoring sib-groups after selection should be considered in any plasticity study that cannot use replicated genotypes. Researchers should monitor changes in allele frequencies as one mechanism to deal with this issue.
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Affiliation(s)
- Mauro Santos
- Departament de Genètica i de Microbiologia, Grup de Genòmica, Bioinformàtica i Biologia Evolutiva (GGBE), Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Margarida Matos
- cE3c-Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Sheng Pei Wang
- Department of Biology, Syracuse University, Syracuse, New York 13244
| | - David M Althoff
- Department of Biology, Syracuse University, Syracuse, New York 13244.,Archbold Biological Station, Venus, Florida, 33960
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Porturas LD, Anneberg TJ, Curé AE, Wang S, Althoff DM, Segraves KA. A meta-analysis of whole genome duplication and the effects on flowering traits in plants. Am J Bot 2019; 106:469-476. [PMID: 30901499 DOI: 10.1002/ajb2.1258] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Accepted: 01/14/2019] [Indexed: 06/09/2023]
Abstract
PREMISE OF THE STUDY Polyploidy, or whole genome duplication (WGD), is common in plants despite theory suggesting that polyploid establishment is challenging and polyploids should be evolutionarily transitory. There is renewed interest in understanding the mechanisms that could facilitate polyploid establishment and explain their pervasiveness in nature. In particular, premating isolation from their diploid progenitors is suggested to be a crucial factor. To evaluate how changes in assortative mating occur, we need to understand the phenotypic effects of WGD on reproductive traits. METHODS We used literature surveys and a meta-analysis to assess how WGD affects floral morphology, flowering phenology, and reproductive output in plants. We focused specifically on comparisons of newly generated polyploids (neopolyploids) and their parents to mitigate potential confounding effects of adaptation and drift that may be present in ancient polyploids. KEY RESULTS The results indicated that across a broad representation of angiosperms, floral morphology traits increased in size, reproductive output decreased, and flowering phenology was unaffected by WGD. Additionally, we found that increased trait variation after WGD was uncommon for the phenotypic traits examined. CONCLUSIONS Our results suggest that the phenotypic effects on traits important to premating isolation of neopolyploids are small, in general. Changes in flowering phenology, reproductive output, and phenotypic variation resulting from WGD may be less critical in facilitating premating isolation and neopolyploid establishment. However, floral traits for which size is an important component of function (e.g., pollen transfer) could be strongly influenced by WGD.
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Affiliation(s)
- Laura D Porturas
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Thomas J Anneberg
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Anne E Curé
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Shengpei Wang
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - David M Althoff
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Kari A Segraves
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
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9
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Wang SP, Althoff DM. Phenotypic plasticity facilitates initial colonization of a novel environment. Evolution 2019; 73:303-316. [DOI: 10.1111/evo.13676] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/30/2018] [Accepted: 12/21/2018] [Indexed: 01/07/2023]
Affiliation(s)
- Sheng Pei Wang
- Department of Biology Syracuse University Syracuse NY 13244
| | - David M. Althoff
- Department of Biology Syracuse University Syracuse NY 13244
- Archbold Biological Station Venus FL 33960
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10
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Affiliation(s)
- David M. Althoff
- Department of Zoology Washington State University Pullman Washington 99164‐4236
| | - John N. Thompson
- Department of Zoology Washington State University Pullman Washington 99164‐4236
- Department of Botany Washington State University Pullman Washington 99164‐4238
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11
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Althoff DM. Specialization in the yucca-yucca moth obligate pollination mutualism: A role for antagonism? Am J Bot 2016; 103:1803-1809. [PMID: 27555437 DOI: 10.3732/ajb.1600053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 05/19/2016] [Indexed: 05/05/2023]
Abstract
PREMISE OF THE STUDY Specialized brood pollination systems involve both mutualism and antagonism in the overall interaction and have led to diversification in both plants and insects. Although largely known for mutualism, the role of the antagonistic side of the interaction in these systems has been overlooked. Specialization may be driven by plant defenses to feeding by the insect larvae that consume and kill developing plant ovules. The interaction among yuccas and yucca moths is cited as a classic example of the importance of mutualism in specialization and diversification. Pollinators moths are very host specific, but whether this specificity is due to adult pollination ability or larval feeding ability is unclear. Here, I test the potential role of antagonism in driving specialization among yuccas and yucca moths. METHODS I examined the ability of the most-polyphagous yucca moth pollinator, Tegeticula yuccasella, to pollinate and develop on five Yucca species used across its range. Yucca species endemic to the Great Plains and Texas were transplanted to a common garden in Syracuse, New York and exposed to the local pollinator moth population over 3 years. KEY RESULTS Local moths visited all but one of the Yucca species, but had drastically lower rates of successful larval development on non-natal Yucca species in comparison to the local host species. CONCLUSION Specialization in many brood pollination systems may be strongly influenced by the antagonistic rather than the mutualistic side of the overall interaction, suggesting that antagonistic coevolution is a possible source of diversification.
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Affiliation(s)
- David M Althoff
- Department of Biology, 107 College Place, Syracuse University, Syracuse, New York 13244 USA
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12
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Hembry DH, Althoff DM. Diversification and coevolution in brood pollination mutualisms: Windows into the role of biotic interactions in generating biological diversity. Am J Bot 2016; 103:1783-1792. [PMID: 27765775 PMCID: PMC6110533 DOI: 10.3732/ajb.1600056] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 05/10/2016] [Indexed: 05/05/2023]
Abstract
Brood pollination mutualisms-interactions in which specialized insects are both the pollinators (as adults) and seed predators (as larvae) of their host plants-have been influential study systems for coevolutionary biology. These mutualisms include those between figs and fig wasps, yuccas and yucca moths, leafflowers and leafflower moths, globeflowers and globeflower flies, Silene plants and Hadena and Perizoma moths, saxifrages and Greya moths, and senita cacti and senita moths. The high reciprocal diversity and species-specificity of some of these mutualisms have been cited as evidence that coevolution between plants and pollinators drives their mutual diversification. However, the mechanisms by which these mutualisms diversify have received less attention. In this paper, we review key hypotheses about how these mutualisms diversify and what role coevolution between plants and pollinators may play in this process. We find that most species-rich brood pollination mutualisms show significant phylogenetic congruence at high taxonomic scales, but there is limited evidence for the processes of both cospeciation and duplication, and there are no unambiguous examples known of strict-sense contemporaneous cospeciation. Allopatric speciation appears important across multiple systems, particularly in the insects. Host-shifts appear to be common, and widespread host-shifts by pollinators may displace other pollinator lineages. There is relatively little evidence for a "coevolution through cospeciation" model or that coevolution promotes speciation in these systems. Although we have made great progress in understanding the mechanisms by which brood pollination mutualisms diversify, many opportunities remain to use these intriguing symbioses to understand the role of biotic interactions in generating biological diversity.
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Affiliation(s)
- David H Hembry
- Department of Ecology and Evolutionary Biology, University of Arizona, P. O. Box 210088, Tucson, Arizona 85721 USA
| | - David M Althoff
- Department of Biology, Syracuse University, 107 College Place, Syracuse, New York, 13244 USA
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13
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Althoff DM. Coevolutionary diversification unfettered. Evolution 2016. [DOI: 10.1111/evo.12962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Rivers DM, Darwell CT, Althoff DM. Phylogenetic analysis of RAD-seq data: examining the influence of gene genealogy conflict on analysis of concatenated data. Cladistics 2016; 32:672-681. [DOI: 10.1111/cla.12149] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2015] [Indexed: 01/15/2023] Open
Affiliation(s)
- David M. Rivers
- Department of Biology; Syracuse University; 107 College Place Syracuse NY 13244 USA
| | - Clive T. Darwell
- Department of Biology; Syracuse University; 107 College Place Syracuse NY 13244 USA
| | - David M. Althoff
- Department of Biology; Syracuse University; 107 College Place Syracuse NY 13244 USA
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15
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Darwell CT, Fox KA, Althoff DM. The roles of geography and founder effects in promoting host-associated differentiation in the generalist bogus yucca moth Prodoxus decipiens. J Evol Biol 2014; 27:2706-18. [PMID: 25403722 DOI: 10.1111/jeb.12529] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 10/03/2014] [Accepted: 10/13/2014] [Indexed: 11/25/2022]
Abstract
There is ample evidence that host shifts in plant-feeding insects have been instrumental in generating the enormous diversity of insects. Changes in host use can cause host-associated differentiation (HAD) among populations that may lead to reproductive isolation and eventual speciation. The importance of geography in facilitating this process remains controversial. We examined the geographic context of HAD in the wide-ranging generalist yucca moth Prodoxus decipiens. Previous work demonstrated HAD among sympatric moth populations feeding on two different Yucca species occurring on the barrier islands of North Carolina, USA. We assessed the genetic structure of P. decipiens across its entire geographic and host range to determine whether HAD is widespread in this generalist herbivore. Population genetic analyses of microsatellite and mtDNA sequence data across the entire range showed genetic structuring with respect to host use and geography. In particular, genetic differentiation was relatively strong between mainland populations and those on the barrier islands of North Carolina. Finer scale analyses, however, among sympatric populations using different host plant species only showed significant clustering based on host use for populations on the barrier islands. Mainland populations did not form population clusters based on host plant use. Reduced genetic diversity in the barrier island populations, especially on the derived host, suggests that founder effects may have been instrumental in facilitating HAD. In general, results suggest that the interplay of local adaptation, geography and demography can determine the tempo of HAD. We argue that future studies should include comprehensive surveys across a wide range of environmental and geographic conditions to elucidate the contribution of various processes to HAD.
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Affiliation(s)
- C T Darwell
- Department of Biology, Syracuse University, Syracuse, NY, USA
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Althoff DM. SHIFT IN EGG-LAYING STRATEGY TO AVOID PLANT DEFENSE LEADS TO REPRODUCTIVE ISOLATION IN MUTUALISTIC AND CHEATING YUCCA MOTHS. Evolution 2013; 68:301-7. [DOI: 10.1111/evo.12279] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 09/19/2013] [Indexed: 11/30/2022]
Affiliation(s)
- David M. Althoff
- Department of Biology; Syracuse University; 107 College Place Syracuse New York 13244
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Althoff DM, Segraves KA, Smith CI, Leebens-Mack J, Pellmyr O. Geographic isolation trumps coevolution as a driver of yucca and yucca moth diversification. Mol Phylogenet Evol 2012; 62:898-906. [DOI: 10.1016/j.ympev.2011.11.024] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 11/07/2011] [Accepted: 11/26/2011] [Indexed: 11/26/2022]
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Althoff DM. THE EVOLUTIONARY UNDERPINNINGS OF MACROECOLOGY. Evolution 2010. [DOI: 10.1111/j.1558-5646.2009.00789.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kolaczan CR, Heard SB, Segraves KA, Althoff DM, Nason JD. Spatial and genetic structure of host-associated differentiation in the parasitoid Copidosoma gelechiae. J Evol Biol 2009; 22:1275-83. [PMID: 19453371 DOI: 10.1111/j.1420-9101.2009.01742.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Host-associated differentiation (HAD) appears to be an important driver of diversification in the hyperdiverse phytophagous and parasitoid insects. The gallmaking moth Gnorimoschema gallaesolidaginis has undergone HAD on two sympatric goldenrods (Solidago), and HAD has also been documented in its parasitoid Copidosoma gelechiae, with the intriguing suggestion that differentiation has proceeded independently in multiple populations. We tested this suggestion with analysis of Amplified Fragment Length Polymorphism (AFLP) markers for C. gelechiae collections from the midwestern and northeastern United States and eastern Canada. AFLP data were consistent with the existence of HAD, with between-host F(ST) significant before Bonferroni correction in two of seven sympatric populations. amova analysis strongly rejected a model of HAD with a single historical origin, and thus supported the repeated-HAD hypothesis. Copidosoma gelechiae shows significant host-associated divergence at a number of allozyme loci (Stireman et al., 2006), but only weak evidence via AFLPs for genome-wide differentiation, suggesting that this species is at a very early stage of HAD.
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Affiliation(s)
- C R Kolaczan
- Department of Biology, University of New Brunswick, Fredericton, NB, Canada
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Smith CI, Pellmyr O, Althoff DM, Balcázar-Lara M, Leebens-Mack J, Segraves KA. Pattern and timing of diversification in Yucca (Agavaceae): specialized pollination does not escalate rates of diversification. Proc Biol Sci 2008; 275:249-58. [PMID: 18048283 DOI: 10.1098/rspb.2007.1405] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The yucca-yucca moth interaction is one of the most well-known and remarkable obligate pollination mutualisms, and is an important study system for understanding coevolution. Previous research suggests that specialist pollinators can promote rapid diversification in plants, and theoretical work has predicted that obligate pollination mutualism promotes cospeciation between plants and their pollinators, resulting in contemporaneous, parallel diversification. However, a lack of information about the age of Yucca has impeded efforts to test these hypotheses. We used analyses of 4322 AFLP markers and cpDNA sequence data representing six non-protein-coding regions (trnT-trnL, trnL, trnL intron, trnL-trnF, rps16 and clpP intron 2) from all 34 species to recover a consensus organismal phylogeny, and used penalized likelihood to estimate divergence times and speciation rates in Yucca. The results indicate that the pollination mutualism did not accelerate diversification, as Yucca diversity (34 species) is not significantly greater than that of its non-moth-pollinated sister group, Agave sensu latissimus (240 species). The new phylogenetic estimates also corroborate the suggestion that the plant-moth pollination mutualism has at least two origins within the Agavaceae. Finally, age estimates show significant discord between the age of Yucca (ca 6-10Myr) and the current best estimates for the age of their pollinators (32-40Myr).
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Althoff DM. A test of host-associated differentiation across the ‘parasite continuum’ in the tri-trophic interaction among yuccas, bogus yucca moths, and parasitoids. Mol Ecol 2008; 17:3917-27. [PMID: 18662219 DOI: 10.1111/j.1365-294x.2008.03874.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- David M Althoff
- Department of Biology, Syracuse University, 130 College Place, Syracuse, NY 13244, USA.
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Althoff DM, Gitzendanner MA, Segraves KA. The utility of amplified fragment length polymorphisms in phylogenetics: a comparison of homology within and between genomes. Syst Biol 2007; 56:477-84. [PMID: 17562471 DOI: 10.1080/10635150701427077] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The amplified fragment length polymorphism (AFLP) technique is being increasingly used in phylogenetic studies, especially in groups of rapidly radiating taxa. One of the key issues in the phylogenetic suitability of this technique is whether the DNA fragments generated via the AFLP method are homologous within and among the taxa being studied. We used a bioinformatics approach to assess homology based on both chromosomal location and sequence similarity of AFLP fragments. The AFLP technique was electronically simulated on genomes from eight organisms that represented a range of genome sizes. The results demonstrated that within a genome, the number of fragments is positively associated with genome size, and the degree of homology decreases with increasing numbers of fragments generated. The average homology of fragments was 89% for small genomes (< 400 Mb) but decreased to 59% for large genomes (> 2 Gb). Fragment homology for large genomes can be increased by excluding smaller fragments, although there is no clear upper limit for the size of fragments to exclude. A second approach is to increase the number of selective nucleotides in the final selective amplification step. For strains of the same organism, homology based on chromosome location and sequence similarity of fragments was 100%. Fragment homology for more distantly related taxa, however, decreased with greater time since divergence. We conclude that AFLP data are best suited for examining phylogeographic patterns within species and among very recently diverged species.
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Affiliation(s)
- David M Althoff
- Department of Biology, Syracuse University, Syracuse, NY 13244, USA.
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Pellmyr O, Segraves KA, Althoff DM, Balcázar-Lara M, Leebens-Mack J. The phylogeny of yuccas. Mol Phylogenet Evol 2007; 43:493-501. [PMID: 17289405 DOI: 10.1016/j.ympev.2006.12.015] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Revised: 12/02/2006] [Accepted: 12/18/2006] [Indexed: 11/29/2022]
Abstract
The genus Yucca is widely recognized for its pollination mutualism with yucca moths. Analysis of diversification in this interaction has been hampered by the lack of a robust phylogeny for the genus. Here we attempt the first extensive nuclear DNA based assessment of the phylogenetic relationships of Yucca. We used AFLP markers to recover the phylogeny of 87 samples representing 38 Yucca taxa. An analysis based on 4322 markers strongly supported a topology consistent with morphological classification at the section level (capsular-fruited Chaenocarpa, fleshy-fruited Sarcocarpa, and spongy-fruited Clistocarpa). Within Sarcocarpa, all but two of the traditional species were monophyletic. Within Chaenocarpa, the morphologically distinct series Rupicolae was strongly supported. In the remaining Chaenocarpa, a western group (Colorado Plateau southward) and an eastern group (Great Plains, central Texas east to Florida) were recovered. Within these groups, where taxonomic circumscriptions are narrow and historically contested, there was at most limited monophyly of traditional taxa, suggesting rapid recent diversification, introgression, or non-monophyletically circumscribed taxa.
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Affiliation(s)
- Olle Pellmyr
- Department of Biology, University of Idaho, Moscow, ID 83844-3051, USA.
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Eigenbrode SD, O'rourke M, Wulfhorst JD, Althoff DM, Goldberg CS, Merrill K, Morse W, Nielsen-Pincus M, Stephens J, Winowiecki L, Bosque-Pérez NA. Employing Philosophical Dialogue in Collaborative Science. Bioscience 2007. [DOI: 10.1641/b570109] [Citation(s) in RCA: 215] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Althoff DM, Svensson GP, Pellmyr O. The influence of interaction type and feeding location on the phylogeographic structure of the yucca moth community associated with Hesperoyucca whipplei. Mol Phylogenet Evol 2006; 43:398-406. [PMID: 17116409 DOI: 10.1016/j.ympev.2006.10.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Revised: 09/18/2006] [Accepted: 10/11/2006] [Indexed: 11/27/2022]
Abstract
The interactions between herbivorous insects and their host plants have been central in generating diversification in both groups. We used a community of four yucca moth species, monophagous on the host plant Hesperoyucca whipplei (Agavaceae), to examine how the type of interaction and where insects feed within a plant influence phylogeographic structure of herbivorous insects. These four species included two fruit-feeders, one mutualistic and one commensalistic, and two commensalistic stalk-feeders. Surveys based on mtDNA cytochrome oxidase I sequence data demonstrated that the moth species differed in phylogeographic history. Populations of the mutualist pollinator, Tegeticula maculata, exhibited the most subdivision in comparison to the three commensal Prodoxus species (both genera in Lepidoptera, Prodoxidae). Feeding location was also correlated with differences in phylogeographic history through its influence on population sizes and the probability of gene flow. The results suggest that both the outcome of interactions and where insects feed may influence population structure.
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Affiliation(s)
- David M Althoff
- Department of Biology, 130 College Place, Syracuse University, Syracuse, NY 13244, USA.
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Althoff DM, Segraves KA, Leebens-Mack J, Pellmyr O. Patterns of Speciation in the Yucca Moths: Parallel Species Radiations within the Tegeticula yuccasella Species Complex. Syst Biol 2006; 55:398-410. [PMID: 16684719 DOI: 10.1080/10635150600697325] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
The interaction between yuccas and yucca moths has been central to understanding the origin and loss of obligate mutualism and mutualism reversal. Previous systematic research using mtDNA sequence data and characters associated with genitalic morphology revealed that a widespread pollinator species in the genus Tegeticula was in fact a complex of pollinator species that differed in host use and the placement of eggs into yucca flowers. Within this mutualistic clade two nonpollinating "cheater" species evolved. Cheaters feed on yucca seeds but lack the tentacular mouthparts necessary for yucca pollination. Previous work suggested that the species complex formed via a rapid radiation within the last several million years. In this study, we use an expanded mtDNA sequence data set and AFLP markers to examine the phylogenetic relationships among this rapidly diverging clade of moths and compare these relationships to patterns in genitalic morphology. Topologies obtained from analyses of the mtDNA and AFLP data differed significantly. Both data sets, however, corroborated the hypothesis of a rapid species radiation and suggested that there were likely two independent species radiations. Morphological analyses based on oviposition habit produced species groupings more similar to the AFLP topology than the mtDNA topology and suggested the two radiations coincided with differences in oviposition habit. The evolution of cheating was reaffirmed to have evolved twice and the closest pollinating relative for one cheater species was identified by both mtDNA and AFLP markers. For the other cheater species, however, the closest pollinating relative remains ambiguous, and mtDNA, AFLP, and morphological data suggest this cheater species may be diverged based on host use. Much of the divergence in the species complex can be explained by geographic isolation associated with the evolution of two oviposition habits.
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Affiliation(s)
- David M Althoff
- Department of Biological Sciences, University of Idaho, Moscow, Idaho 83844-3051, USA.
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Abstract
Mutualisms are balanced antagonistic interactions where both species gain a net benefit. Because mutualisms generate resources, they can be exploited by individuals that reap the benefits of the interaction without paying any cost. The presence of such 'cheaters' may have important consequences, yet we are only beginning to understand how cheaters evolve from mutualists and how their evolution may be curtailed within mutualistic lineages. The yucca-yucca moth pollination mutualism is an excellent model in this context as there have been two origins of cheating from within the yucca moth lineage. We used nuclear and mitochondrial DNA markers to examine genetic structure in a moth population where a cheater species is parapatric with a resident pollinator. The results revealed extensive hybridization between pollinators and cheaters. Hybrids were genetically intermediate to parental populations, even though all individuals in this population had a pollinator phenotype. The results suggest that mutualisms can be stable in the face of introgression of cheater genes and that the ability of cheaters to invade a given mutualism may be more limited than previously appreciated.
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Affiliation(s)
- Kari A Segraves
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844-3051, USA.
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Althoff DM, Segraves KA, Sparks JP. Characterizing the interaction between the bogus yucca moth and yuccas: do bogus yucca moths impact yucca reproductive success? Oecologia 2004; 140:321-7. [PMID: 15170561 DOI: 10.1007/s00442-004-1584-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2003] [Accepted: 04/07/2004] [Indexed: 10/26/2022]
Abstract
Yucca moths are most well known for their obligate pollination mutualism with yuccas, where pollinator moths provide yuccas with pollen and, in exchange, the moth larvae feed on a subset of the developing yucca seeds. The pollinators, however, comprise only two of the three genera of yucca moths. Members of the third genus, Prodoxus, are the "bogus yucca moths" and are sister to the pollinator moths. Adult Prodoxus lack the specialized mouthparts used for pollination and the larvae feed on plant tissues other than seeds. Prodoxus larvae feed within the same plants as pollinator larvae and have the potential to influence yucca reproductive success directly by drawing resources away from flowers and fruit, or indirectly by modifying the costs of the mutualism with pollinators. We examined the interaction between the scape-feeding bogus yucca moth, Prodoxus decipiens, and one of its yucca hosts, Yucca filamentosa, by comparing female reproductive success of plants with and without moth larvae. We determined reproductive success by measuring a set of common reproductive traits such as flowering characteristics, seed set, and seed germination. In addition, we also quantified the percent total nitrogen in the seeds to determine whether the presence of larvae could potentially reduce seed quality. Flowering characteristics, seed set, and seed germination were not significantly different between plants with and without bogus yucca moth larvae. In contrast, the percent total nitrogen content of seeds was significantly lower in plants with P. decipiens larvae, and nitrogen content was negatively correlated with the number of larvae feeding within the inflorescence scape. Surveys of percent total nitrogen at three time periods during the flowering and fruiting of Y. filamentosa also showed that larval feeding decreased the amount of nitrogen in fruit tissue. Taken together, the results suggest that although P. decipiens influences nitrogen distribution in Y. filamentosa, this physiological effect does not appear to impact the female components of reproductive success.
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Affiliation(s)
- David M Althoff
- Department of Biological Sciences, University of Idaho, Rm 252 Life Sciences South, Moscow, ID, 83844-3051, USA.
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Abstract
Understanding the phylogeography of a species requires not only elucidating patterns of genetic structure among populations, but also identifying the possible evolutionary events creating that structure. The use of a single phylogeographic test or analysis, however, usually provides a picture of genetic structure without revealing the possible underlying evolutionary causes. We used current analytical techniques in a sequential approach to examine genetic structure and its underlying causes in the bogus yucca moth Prodoxus decipiens (Lepidoptera: Prodoxidae). Both historical biogeography and recent human transplantations of the moth's host plants provided a priori expectations of the pattern of genetic structure and its underlying causes. We evaluated these expectations by using a progression of phylogenetic, demographic, and population genetic analyses of mtDNA sequence data from 476 individuals distributed across 25 populations that encompassed the range of P. decipiens. The combination of these analyses revealed that much of the genetic structure has evolved more recently than suggested by historical biogeography, has been influenced by changes in demography, and can be best explained by long distance dispersal and isolation by distance. We suggest that performing a suite of analyses that focus on different temporal scales may be an effective approach to investigating the patterns and causes of genetic structure within species.
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Affiliation(s)
- David M Althoff
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235, USA.
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Althoff DM, Groman JD, Segraves KA, Pellmyr O. Phylogeographic structure in the bogus yucca moth Prodoxus quinquepunctellus (Prodoxidae): comparisons with coexisting pollinator yucca moths. Mol Phylogenet Evol 2001; 21:117-27. [PMID: 11603942 DOI: 10.1006/mpev.2001.0995] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The pollination mutualism between yucca moths and yuccas highlights the potential importance of host plant specificity in insect diversification. Historically, one pollinator moth species, Tegeticula yuccasella, was believed to pollinate most yuccas. Recent phylogenetic studies have revealed that it is a complex of at least 13 distinct species, eight of which are specific to one yucca species. Moths in the closely related genus Prodoxus also specialize on yuccas, but they do not pollinate and their larvae feed on different plant parts. Previous research demonstrated that the geographically widespread Prodoxus quinquepunctellus can rapidly specialize to its host plants and may harbor hidden species diversity. We examined the phylogeographic structure of P. quinquepunctellus across its range to compare patterns of diversification with six coexisting pollinator yucca moth species. Morphometric and mtDNA cytochrome oxidase I sequence data indicated that P. quinquepunctellus as currently described contains two species. There was a deep division between moth populations in the eastern and the western United States, with limited sympatry in central Texas; these clades are considered separate species and are redescribed as P. decipiens and P. quinquepunctellus (sensu stricto), respectively. Sequence data also showed a lesser division within P. quinquepunctellus s.s. between the western populations on the Colorado Plateau and those elsewhere. The divergence among the three emerging lineages corresponded with major biogeographic provinces, whereas AMOVA indicated that host plant specialization has been relatively unimportant in diversification. In comparison, the six pollinator species comprise three lineages, one eastern and two western. A pollinator species endemic to the Colorado Plateau has evolved in both of the western lineages. The east-west division and the separate evolution of two Colorado Plateau pollinator species suggest that similar biogeographic factors have influenced diversification in both Tegeticula and Prodoxus. For the pollinators, however, each lineage has produced a monophagous species, a pattern not seen in P. quinquepunctellus.
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Affiliation(s)
- D M Althoff
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235, USA.
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