1
|
Kokate PP, Smith M, Hall L, Zhang K, Werner T. Inter- and intraspecific variation in mycotoxin tolerance: A study of four Drosophila species. Ecol Evol 2022; 12:e9126. [PMID: 35898423 PMCID: PMC9309036 DOI: 10.1002/ece3.9126] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 05/11/2022] [Accepted: 06/23/2022] [Indexed: 12/03/2022] Open
Abstract
Many mycophagous Drosophila species have adapted to tolerate high concentrations of mycotoxins, an ability not reported in any other eukaryotes. Although an association between mycophagy and mycotoxin tolerance has been established in many Drosophila species, the genetic mechanisms of the tolerance are unknown. This study presents the inter‐ and intraspecific variation in the mycotoxin tolerance trait. We studied the mycotoxin tolerance in four Drosophila species from four separate clades within the immigrans‐tripunctata radiation from two distinct locations. The effect of mycotoxin treatment on 20 isofemale lines per species was studied using seven gross phenotypes: survival to pupation, survival to eclosion, development time to pupation and eclosion, thorax length, fecundity, and longevity. We observed interspecific variation among four species, with D. falleni being the most tolerant, followed by D. recens, D. neotestacea, and D. tripunctata, in that order. The results also revealed geographical variation and intraspecific genetic variation in mycotoxin tolerance. This report provides the foundation for further delineating the genetic mechanisms of the mycotoxin tolerance trait.
Collapse
Affiliation(s)
- Prajakta P Kokate
- Department of Biological Sciences Michigan Technological University Houghton Michigan USA
| | - Morgan Smith
- Department of Biological Sciences Michigan Technological University Houghton Michigan USA
| | - Lucinda Hall
- Department of Biological Sciences Michigan Technological University Houghton Michigan USA
| | - Kui Zhang
- Department of Mathematical Sciences Michigan Technological University Houghton Michigan USA
| | - Thomas Werner
- Department of Biological Sciences Michigan Technological University Houghton Michigan USA
| |
Collapse
|
2
|
Dion WA, Shittu MO, Steenwinkel TE, Raja KKB, Kokate PP, Werner T. The modular expression patterns of three pigmentation genes prefigure unique abdominal morphologies seen among three Drosophila species. Gene Expr Patterns 2020; 38:119132. [PMID: 32828854 PMCID: PMC7725850 DOI: 10.1016/j.gep.2020.119132] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/07/2020] [Accepted: 08/09/2020] [Indexed: 02/07/2023]
Abstract
To understand how novel animal body colorations emerged, one needs to ask how the development of color patterns differs among closely related species. Here we examine three species of fruit flies - Drosophila guttifera (D. guttifera), D. palustris, and D. subpalustris - displaying a varying number of abdominal spot rows. Through in situ hybridization experiments, we examine the mRNA expression patterns for the pigmentation genes Dopa decarboxylase (Ddc), tan (t), and yellow (y) during pupal development. Our results show that Ddc, t, and y are co-expressed in modular, identical patterns, each foreshadowing the adult abdominal spots in D. guttifera, D. palustris, and D. subpalustris. We suggest that differences in the expression patterns of these three genes partially underlie the morphological diversity of the quinaria species group.
Collapse
Affiliation(s)
- William A Dion
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA
| | - Mujeeb O Shittu
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA
| | - Tessa E Steenwinkel
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA
| | - Komal K B Raja
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA
| | - Prajakta P Kokate
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA
| | - Thomas Werner
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA.
| |
Collapse
|
3
|
Scott Chialvo CH, Griffin LH, Reed LK, Ciesla L. Exhaustive extraction of cyclopeptides from Amanita phalloides: Guidelines for working with complex mixtures of secondary metabolites. Ecol Evol 2020; 10:4233-4240. [PMID: 32489592 PMCID: PMC7246195 DOI: 10.1002/ece3.6191] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 12/16/2019] [Accepted: 12/20/2019] [Indexed: 12/28/2022] Open
Abstract
Understanding plant-insect interactions is an active area of research in both ecology and evolution. Much attention has been focused on the impact of secondary metabolites in the host plant or fungi on these interactions. Plants and fungi contain a variety of biologically active compounds, and the secondary metabolite profile can vary significantly between individual samples. However, many experiments characterize the biological effects of only a single secondary metabolite or a subset of these compounds.Here, we develop an exhaustive extraction protocol using an accelerated solvent extraction protocol to recover the complete suite of cyclopeptides and other secondary metabolites found in Amanita phalloides (death cap mushrooms) and compare its efficacy to the "Classic" extraction method used in earlier works.We demonstrate that our extraction protocol recovers the full suite of cyclopeptides and other secondary metabolites in A. phalloides unlike the "Classic" method that favors polar cyclopeptides.Based on these findings, we provide recommendations for how to optimize protocols to ensure exhaustive extracts and also the best practices when using natural extracts in ecological experiments.
Collapse
Affiliation(s)
- Clare H. Scott Chialvo
- Department of Biological SciencesUniversity of AlabamaTuscaloosaALUSA
- Department of BiologyAppalachian State UniversityBooneNCUSA
| | - Logan H. Griffin
- Department of Biological SciencesUniversity of AlabamaTuscaloosaALUSA
| | - Laura K. Reed
- Department of Biological SciencesUniversity of AlabamaTuscaloosaALUSA
| | - Lukasz Ciesla
- Department of Biological SciencesUniversity of AlabamaTuscaloosaALUSA
| |
Collapse
|
4
|
Scott Chialvo CH, White BE, Reed LK, Dyer KA. A phylogenetic examination of host use evolution in the quinaria and testacea groups of Drosophila. Mol Phylogenet Evol 2018; 130:233-243. [PMID: 30366088 DOI: 10.1016/j.ympev.2018.10.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/05/2018] [Accepted: 10/20/2018] [Indexed: 12/26/2022]
Abstract
Adaptive radiations provide an opportunity to examine complex evolutionary processes such as ecological specialization and speciation. While a well-resolved phylogenetic hypothesis is critical to completing such studies, the rapid rates of evolution in these groups can impede phylogenetic studies. Here we study the quinaria and testacea species groups of the immigrans-tripunctata radiation of Drosophila, which represent a recent adaptive radiation and are a developing model system for ecological genetics. We were especially interested in understanding host use evolution in these species. In order to infer a phylogenetic hypothesis for this group we sampled loci from both the nuclear genome and the mitochondrial DNA to develop a dataset of 43 protein-coding loci for these two groups along with their close relatives in the immigrans-tripunctata radiation. We used this dataset to examine their evolutionary relationships along with the evolution of feeding behavior. Our analysis recovers strong support for the monophyly of the testacea but not the quinaria group. Results from our ancestral state reconstruction analysis suggests that the ancestor of the testacea and quinaria groups exhibited mushroom-feeding. Within the quinaria group, we infer that transition to vegetative feeding occurred twice, and that this transition did not coincide with a genome-wide change in the rate of protein evolution.
Collapse
Affiliation(s)
- Clare H Scott Chialvo
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA.
| | - Brooke E White
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Laura K Reed
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA
| | - Kelly A Dyer
- Department of Genetics, University of Georgia, Athens, GA 30602, USA.
| |
Collapse
|
5
|
Jaenike J. SUPPRESSION OF SEX-RATIO MEIOTIC DRIVE AND THE MAINTENANCE OF Y-CHROMOSOME POLYMORPHISM IN DROSOPHILA. Evolution 2017; 53:164-174. [PMID: 28565182 DOI: 10.1111/j.1558-5646.1999.tb05342.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/1998] [Accepted: 09/10/1998] [Indexed: 11/29/2022]
Abstract
Like several other species of Drosophila, D. quinaria is polymorphic for X-chromosome meiotic drive; matings involving males that carry a "sex-ratio" X chromosome (XSR ) result in the production of strongly female-biased offspring sex ratios (Jaenike 1996). A survey of isofemale lines of D. quinaria from several populations reveals that there is genetic variation for partial suppression of this meiotic drive. Crossing experiments show that there is Y-linked, and probably autosomal, variation for suppression of drive. Y-linked suppressors of X-chromosome drive have now been described in several species of Diptera. I develop a simple model for the maintenance of Y-chromosome polymorphism in species polymorphic for X-linked meiotic drive. One interesting feature of this model is that, if there is a stable Y-chromosome polymorphism, then the equilibrium frequency of the standard and sex-ratio X chromosomes is determined solely by Y-chromosome parameters, not by the fitness effects of the different X chromosomes on their carriers. This model suggests that Y-chromosome polymorphism may be easier to maintain than previously thought, and I hypothesize that karyotypic variation in Y chromosomes will be found to be associated with suppression of sex-ratio meiotic drive in other species of Drosophila.
Collapse
Affiliation(s)
- John Jaenike
- Department of Biology, University of Rochester, Rochester, New York, 14627
| |
Collapse
|
6
|
Pitnick S, Marrow T, Spicer GS. EVOLUTION OF MULTIPLE KINDS OF FEMALE SPERM-STORAGE ORGANS IN DROSOPHILA. Evolution 2017; 53:1804-1822. [PMID: 28565462 DOI: 10.1111/j.1558-5646.1999.tb04564.x] [Citation(s) in RCA: 164] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/1998] [Accepted: 06/02/1999] [Indexed: 11/27/2022]
Abstract
Females of all species belonging to the family Drosophilidae have two kinds of sperm-storage organs: paired spherical spermathecae and a single elongate tubular seminal receptacle. We examined 113 species belonging to the genus Drosophila and closely allied genera and describe variation in female sperm-storage organ use and morphology. The macroevolutionary pattern of organ dysfunction and morphological divergence suggests that ancestrally both kinds of organs stored sperm. Loss of use of the spermathecae has evolved at least 13 times; evolutionary regain of spermathecal function has rarely if ever occurred. Loss of use of the seminal receptacle has likely occurred only once; in this case, all descendant species possess unusually elaborate spermathecae. Data further indicate that the seminal receptacle is the primary sperm-storage organ in Drosophila. This organ exhibits a pattern of strong correlated evolution with the length of sperm. The evolution of multiple kinds of female sperm-storage organs and the rapidly divergent and correlated evolution of sperm and female reproductive tract morphology are discussed.
Collapse
Affiliation(s)
- Scott Pitnick
- Department of Biology, Syracuse University, 108 College Place, Syracuse, New York, 13244-1270
| | - Therese Marrow
- Department of Zoology, Arizona State University, Tempe, Arizona, 85287-1501
| | - Greg S Spicer
- Department of Biology, San Francisco State University, San Francisco, California, 94132-1722
| |
Collapse
|
7
|
Pitnick S, Spicer GS, Markow T. PHYLOGENETIC EXAMINATION OF FEMALE INCORPORATION OF EJACULATE IN
DROSOPHILA. Evolution 2017; 51:833-845. [DOI: 10.1111/j.1558-5646.1997.tb03665.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/1996] [Accepted: 01/28/1997] [Indexed: 11/29/2022]
Affiliation(s)
- Scott Pitnick
- Department of Biology Syracuse University 108 College Place, Syracuse New York 13244‐1270
| | - Greg S. Spicer
- Department of Biology San Francisco State University San Francisco California 94132‐1722
| | - Therese Markow
- Department of Biology Syracuse University 108 College Place, Syracuse New York 13244‐1270
- Department of Zoology Arizona State University Tempe Arizona 85287‐1501
| |
Collapse
|
8
|
The genus Drosophila is characterized by a large number of sibling species showing evolutionary significance. J Genet 2017; 95:1053-1064. [PMID: 27994208 DOI: 10.1007/s12041-016-0699-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Mayr (1942) defined sibling species as sympatric forms which are morphologically very similar or indistinguishable, but which possess specific biological characteristics and are reproductively isolated. Another term, cryptic species has also been used for such species. However, this concept changed later. Sibling species are as similar as twins. This category does not necessarily include phylogenetic siblings as members of a superspecies. Since the term sibling species was defined by Mayr, a large number of cases of sibling species pairs/groups have been reported and thus they are widespread in the animal kingdom. However, they seem to be more common in some groups such as insects. In insects, they have been reported in diptera, lepidoptera, coleoptera, orthoptera, hymenoptera and others. Sibling species are widespread among the dipteran insects and as such are well studied because some species are important medically (mosquitoes), genetically (Drosophila) and cytologically (Sciara and Chironomus). The well-studied classical pairs of sibling species in Drosophila are: D. pseudoobscura and D. persimilis, and D. melanogaster and D. simulans. Subsequently, a number of sibling species have been added to these pairs and a large number of other sibling species pairs/groups in different species groups of the genus Drosophila have been reported in literature. The present review briefly summarizes the cases of sibling species pairs/groups in the genus Drosophila with their evolutionary significance.
Collapse
|
9
|
Mitchell CL, Latuszek CE, Vogel KR, Greenlund IM, Hobmeier RE, Ingram OK, Dufek SR, Pecore JL, Nip FR, Johnson ZJ, Ji X, Wei H, Gailing O, Werner T. α-amanitin resistance in Drosophila melanogaster: A genome-wide association approach. PLoS One 2017; 12:e0173162. [PMID: 28241077 PMCID: PMC5328632 DOI: 10.1371/journal.pone.0173162] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 02/15/2017] [Indexed: 11/17/2022] Open
Abstract
We investigated the mechanisms of mushroom toxin resistance in the Drosophila Genetic Reference Panel (DGRP) fly lines, using genome-wide association studies (GWAS). While Drosophila melanogaster avoids mushrooms in nature, some lines are surprisingly resistant to α-amanitin—a toxin found solely in mushrooms. This resistance may represent a pre-adaptation, which might enable this species to invade the mushroom niche in the future. Although our previous microarray study had strongly suggested that pesticide-metabolizing detoxification genes confer α-amanitin resistance in a Taiwanese D. melanogaster line Ama-KTT, none of the traditional detoxification genes were among the top candidate genes resulting from the GWAS in the current study. Instead, we identified Megalin, Tequila, and widerborst as candidate genes underlying the α-amanitin resistance phenotype in the North American DGRP lines, all three of which are connected to the Target of Rapamycin (TOR) pathway. Both widerborst and Tequila are upstream regulators of TOR, and TOR is a key regulator of autophagy and Megalin-mediated endocytosis. We suggest that endocytosis and autophagy of α-amanitin, followed by lysosomal degradation of the toxin, is one of the mechanisms that confer α-amanitin resistance in the DGRP lines.
Collapse
Affiliation(s)
- Chelsea L Mitchell
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Catrina E Latuszek
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Kara R Vogel
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, 1300 University Ave., Madison, WI, United States of America
| | - Ian M Greenlund
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Rebecca E Hobmeier
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Olivia K Ingram
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Shannon R Dufek
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Jared L Pecore
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Felicia R Nip
- College of Human Medicine, Michigan State University, Clinical Center, East Lansing, MI, United States of America
| | - Zachary J Johnson
- U.S. Forest Service, Salt Lake Ranger District 6944 S, 3000 E, Salt Lake City, UT, United States of America
| | - Xiaohui Ji
- School of Forest Resources and Environmental Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Hairong Wei
- School of Forest Resources and Environmental Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Oliver Gailing
- School of Forest Resources and Environmental Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Thomas Werner
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| |
Collapse
|
10
|
Izumitani HF, Kusaka Y, Koshikawa S, Toda MJ, Katoh T. Phylogeography of the Subgenus Drosophila (Diptera: Drosophilidae): Evolutionary History of Faunal Divergence between the Old and the New Worlds. PLoS One 2016; 11:e0160051. [PMID: 27462734 PMCID: PMC4962979 DOI: 10.1371/journal.pone.0160051] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 07/13/2016] [Indexed: 11/19/2022] Open
Abstract
The current subgenus Drosophila (the traditional immigrans-tripunctata radiation) includes major elements of temperate drosophilid faunas in the northern hemisphere. Despite previous molecular phylogenetic analyses, the phylogeny of the subgenus Drosophila has not fully been resolved: the resulting trees have more or less varied in topology. One possible factor for such ambiguous results is taxon-sampling that has been biased towards New World species in previous studies. In this study, taxon sampling was balanced between Old and New World species, and phylogenetic relationships among 45 ingroup species selected from ten core species groups of the subgenus Drosophila were analyzed using nucleotide sequences of three nuclear and two mitochondrial genes. Based on the resulting phylogenetic tree, ancestral distributions and divergence times were estimated for each clade to test Throckmorton’s hypothesis that there was a primary, early-Oligocene disjunction of tropical faunas and a subsequent mid-Miocene disjunction of temperate faunas between the Old and the New Worlds that occurred in parallel in separate lineages of the Drosophilidae. Our results substantially support Throckmorton’s hypothesis of ancestral migrations via the Bering Land Bridge mainly from the Old to the New World, and subsequent vicariant divergence of descendants between the two Worlds occurred in parallel among different lineages of the subgenus Drosophila. However, our results also indicate that these events took place multiple times over a wider time range than Throckmorton proposed, from the late Oligocene to the Pliocene.
Collapse
Affiliation(s)
- Hiroyuki F. Izumitani
- Department of Natural History Science, Graduate school of Science, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Yohei Kusaka
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo, Japan
| | - Shigeyuki Koshikawa
- The Hakubi Center for Advanced Research and Graduate School of Science, Kyoto University, Kyoto, Kyoto, Japan
| | - Masanori J. Toda
- Hokkaido University Museum, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Toru Katoh
- Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Hokkaido, Japan
- * E-mail:
| |
Collapse
|
11
|
Mitchell CL, Yeager RD, Johnson ZJ, D’Annunzio SE, Vogel KR, Werner T. Long-Term Resistance of Drosophila melanogaster to the Mushroom Toxin Alpha-Amanitin. PLoS One 2015; 10:e0127569. [PMID: 25978397 PMCID: PMC4433104 DOI: 10.1371/journal.pone.0127569] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 04/16/2015] [Indexed: 11/19/2022] Open
Abstract
Insect resistance to toxins exerts not only a great impact on our economy, but also on the ecology of many species. Resistance to one toxin is often associated with cross-resistance to other, sometimes unrelated, chemicals. In this study, we investigated mushroom toxin resistance in the fruit fly Drosophila melanogaster (Meigen). This fruit fly species does not feed on mushrooms in nature and may thus have evolved cross-resistance to α-amanitin, the principal toxin of deadly poisonous mushrooms, due to previous pesticide exposure. The three Asian D. melanogaster stocks used in this study, Ama-KTT, Ama-MI, and Ama-KLM, acquired α-amanitin resistance at least five decades ago in their natural habitats in Taiwan, India, and Malaysia, respectively. Here we show that all three stocks have not lost the resistance phenotype despite the absence of selective pressure over the past half century. In response to α-amanitin in the larval food, several signs of developmental retardation become apparent in a concentration-dependent manner: higher pre-adult mortality, prolonged larva-to-adult developmental time, decreased adult body size, and reduced adult longevity. In contrast, female fecundity nearly doubles in response to higher α-amanitin concentrations. Our results suggest that α-amanitin resistance has no fitness cost, which could explain why the resistance has persisted in all three stocks over the past five decades. If pesticides caused α-amanitin resistance in D. melanogaster, their use may go far beyond their intended effects and have long-lasting effects on ecosystems.
Collapse
Affiliation(s)
- Chelsea L. Mitchell
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, United States of America
| | - Roger D. Yeager
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, United States of America
| | - Zachary J. Johnson
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, United States of America
| | - Stephanie E. D’Annunzio
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, United States of America
| | - Kara R. Vogel
- Department of Experimental and Systems Pharmacology, Washington State University, Spokane, Washington, United States of America
| | - Thomas Werner
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, United States of America
- * E-mail:
| |
Collapse
|
12
|
Arthur NJ, Dyer KA. Asymmetrical sexual isolation but no postmating isolation between the closely related species Drosophila suboccidentalis and Drosophila occidentalis. BMC Evol Biol 2015; 15:38. [PMID: 25881167 PMCID: PMC4369358 DOI: 10.1186/s12862-015-0328-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 02/24/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND During the speciation process several types of isolating barriers can arise that limit gene flow between diverging populations. Studying recently isolated species can inform our understanding of how and when these barriers arise, and which barriers may be most important to limiting gene flow. Here we focus on Drosophila suboccidentalis and D. occidentalis, which are closely related mushroom-feeding species that inhabit western North America and are not known to overlap in geographic range. We investigate patterns of reproductive isolation between these species, including premating, postmating prezygotic, and postzygotic barriers to gene flow. RESULTS Using flies that originate from a single population of each species, we find that the strength of premating sexual isolation between these species is asymmetric: while D. occidentalis females mate with D. suboccidentalis males at a reduced but moderate rate, D. suboccidentalis females discriminate strongly against mating with D. occidentalis males. Female hybrids will mate at high rates with males of either species, indicating that this discrimination has a recessive genetic basis. Hybrid males are accepted by females of both species. We do not find evidence for postmating prezygotic or postzygotic isolating barriers, as females use the sperm of heterospecific males and both male and female hybrids are fully fertile. CONCLUSIONS Premating isolation is substantial but incomplete, and appears to be the primary form of reproductive isolation between these species. If these species do hybridize, the lack of postzygotic barriers may allow for gene flow between them. Given that these species are recently diverged and are not known to be sympatric, the level of premating isolation is relatively strong given the lack of intrinsic postzygotic isolation. Further work is necessary to characterize the geographic and genetic variation in reproductive isolating barriers, as well as to determine the factors that drive reproductive isolation and the consequences that isolating barriers as well as geographic isolation have had on patterns of gene flow between these species.
Collapse
Affiliation(s)
- Nicholas J Arthur
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA.
| | - Kelly A Dyer
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA.
| |
Collapse
|
13
|
de Roode JC, Lefèvre T. Behavioral Immunity in Insects. INSECTS 2012; 3:789-820. [PMID: 26466629 PMCID: PMC4553590 DOI: 10.3390/insects3030789] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Revised: 07/03/2012] [Accepted: 07/10/2012] [Indexed: 12/29/2022]
Abstract
Parasites can dramatically reduce the fitness of their hosts, and natural selection should favor defense mechanisms that can protect hosts against disease. Much work has focused on understanding genetic and physiological immunity against parasites, but hosts can also use behaviors to avoid infection, reduce parasite growth or alleviate disease symptoms. It is increasingly recognized that such behaviors are common in insects, providing strong protection against parasites and parasitoids. We review the current evidence for behavioral immunity in insects, present a framework for investigating such behavior, and emphasize that behavioral immunity may act through indirect rather than direct fitness benefits. We also discuss the implications for host-parasite co-evolution, local adaptation, and the evolution of non-behavioral physiological immune systems. Finally, we argue that the study of behavioral immunity in insects has much to offer for investigations in vertebrates, in which this topic has traditionally been studied.
Collapse
Affiliation(s)
- Jacobus C de Roode
- Department of Biology, Emory University, 1510 Clifton Road, Atlanta, GA 30322, USA.
| | - Thierry Lefèvre
- MIVEGEC (UM1-UM2-CNRS 5290-IRD 224), Centre IRD, 911 Av. Agropolis-BP 64501, Montpellier 34394, France.
| |
Collapse
|
14
|
Chandler JA, Lang JM, Bhatnagar S, Eisen JA, Kopp A. Bacterial communities of diverse Drosophila species: ecological context of a host-microbe model system. PLoS Genet 2011; 7:e1002272. [PMID: 21966276 PMCID: PMC3178584 DOI: 10.1371/journal.pgen.1002272] [Citation(s) in RCA: 501] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 07/18/2011] [Indexed: 02/06/2023] Open
Abstract
Drosophila melanogaster is emerging as an important model of non-pathogenic host-microbe interactions. The genetic and experimental tractability of Drosophila has led to significant gains in our understanding of animal-microbial symbiosis. However, the full implications of these results cannot be appreciated without the knowledge of the microbial communities associated with natural Drosophila populations. In particular, it is not clear whether laboratory cultures can serve as an accurate model of host-microbe interactions that occur in the wild, or those that have occurred over evolutionary time. To fill this gap, we characterized natural bacterial communities associated with 14 species of Drosophila and related genera collected from distant geographic locations. To represent the ecological diversity of Drosophilids, examined species included fruit-, flower-, mushroom-, and cactus-feeders. In parallel, wild host populations were compared to laboratory strains, and controlled experiments were performed to assess the importance of host species and diet in shaping bacterial microbiome composition. We find that Drosophilid flies have taxonomically restricted bacterial communities, with 85% of the natural bacterial microbiome composed of only four bacterial families. The dominant bacterial taxa are widespread and found in many different host species despite the taxonomic, ecological, and geographic diversity of their hosts. Both natural surveys and laboratory experiments indicate that host diet plays a major role in shaping the Drosophila bacterial microbiome. Despite this, the internal bacterial microbiome represents only a highly reduced subset of the external bacterial communities, suggesting that the host exercises some level of control over the bacteria that inhabit its digestive tract. Finally, we show that laboratory strains provide only a limited model of natural host-microbe interactions. Bacterial taxa used in experimental studies are rare or absent in wild Drosophila populations, while the most abundant associates of natural Drosophila populations are rare in the lab.
Collapse
Affiliation(s)
- James Angus Chandler
- Center for Population Biology, Department of Evolution and Ecology, University of California Davis, Davis, California, USA.
| | | | | | | | | |
Collapse
|