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Oettler J, Suefuji M, Heinze J. THE EVOLUTION OF ALTERNATIVE REPRODUCTIVE TACTICS IN MALE CARDIOCONDYLA ANTS. Evolution 2010; 64:3310-7. [DOI: 10.1111/j.1558-5646.2010.01090.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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202
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A sophisticated, modular communication contributes to ecological dominance in the invasive ant Anoplolepis gracilipes. Biol Invasions 2010. [DOI: 10.1007/s10530-010-9750-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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203
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Planqué R, van den Berg JB, Franks NR. Recruitment strategies and colony size in ants. PLoS One 2010; 5:e11664. [PMID: 20694195 PMCID: PMC2915909 DOI: 10.1371/journal.pone.0011664] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 06/24/2010] [Indexed: 11/18/2022] Open
Abstract
Ants use a great variety of recruitment methods to forage for food or find new nests, including tandem running, group recruitment and scent trails. It has been known for some time that there is a loose correlation across many taxa between species-specific mature colony size and recruitment method. Very small colonies tend to use solitary foraging; small to medium sized colonies use tandem running or group recruitment whereas larger colonies use pheromone recruitment trails. Until now, explanations for this correlation have focused on the ants' ecology, such as food resource distribution. However, many species have colonies with a single queen and workforces that grow over several orders of magnitude, and little is known about how a colony's organization, including recruitment methods, may change during its growth. After all, recruitment involves interactions between ants, and hence the size of the colony itself may influence which recruitment method is used—even if the ants' behavioural repertoire remains unchanged. Here we show using mathematical models that the observed correlation can also be explained by recognizing that failure rates in recruitment depend differently on colony size in various recruitment strategies. Our models focus on the build up of recruiter numbers inside colonies and are not based on optimality arguments, such as maximizing food yield. We predict that ant colonies of a certain size should use only one recruitment method (and always the same one) rather than a mix of two or more. These results highlight the importance of the organization of recruitment and how it is affected by colony size. Hence these results should also expand our understanding of ant ecology.
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Affiliation(s)
- Robert Planqué
- Department of Mathematics, VU University Amsterdam, Amsterdam, The Netherlands.
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204
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Marazzi B, Sanderson MJ. LARGE-SCALE PATTERNS OF DIVERSIFICATION IN THE WIDESPREAD LEGUME GENUS SENNA AND THE EVOLUTIONARY ROLE OF EXTRAFLORAL NECTARIES. Evolution 2010; 64:3570-92. [DOI: 10.1111/j.1558-5646.2010.01086.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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205
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Smith CR, Dolezal A, Eliyahu D, Holbrook CT, Gadau J. Ants (Formicidae): models for social complexity. Cold Spring Harb Protoc 2010; 2009:pdb.emo125. [PMID: 20147200 DOI: 10.1101/pdb.emo125] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The family Formicidae (ants) is composed of more than 12,000 described species that vary greatly in size, morphology, behavior, life history, ecology, and social organization. Ants occur in most terrestrial habitats and are the dominant animals in many of them. They have been used as models to address fundamental questions in ecology, evolution, behavior, and development. The literature on ants is extensive, and the natural history of many species is known in detail. Phylogenetic relationships for the family, as well as within many subfamilies, are known, enabling comparative studies. Their ease of sampling and ecological variation makes them attractive for studying populations and questions relating to communities. Their sociality and variation in social organization have contributed greatly to an understanding of complex systems, division of labor, and chemical communication. Ants occur in colonies composed of tens to millions of individuals that vary greatly in morphology, physiology, and behavior; this variation has been used to address proximate and ultimate mechanisms generating phenotypic plasticity. Relatedness asymmetries within colonies have been fundamental to the formulation and empirical testing of kin and group selection theories. Genomic resources have been developed for some species, and a whole-genome sequence for several species is likely to follow in the near future; comparative genomics in ants should provide new insights into the evolution of complexity and sociogenomics. Future studies using ants should help establish a more comprehensive understanding of social life, from molecules to colonies.
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Affiliation(s)
- Chris R Smith
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA.
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206
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207
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Kück P, Meusemann K. FASconCAT: Convenient handling of data matrices. Mol Phylogenet Evol 2010; 56:1115-8. [PMID: 20416383 DOI: 10.1016/j.ympev.2010.04.024] [Citation(s) in RCA: 311] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 04/14/2010] [Accepted: 04/15/2010] [Indexed: 10/19/2022]
Abstract
FASconCAT is a user-friendly software that concatenates rapidly different kinds of sequence data into one supermatrix file. Output files are either in FASTA, PHYLIP or NEXUS format and are directly loadable in phylogenetic programs like PAUP *, RAxML or MrBayes. FASconCAT can handle FASTA, PHYLIP and CLUSTAL formatted input files in one single run. It provides useful information about each input file and the concatenated supermatrix. For example, the program provides the range information of each concatenated gene (partition) and delivers a check list of all concatenated sequences (taxa). Information about the base composition of single input files and the resulting supermatrix is supplied for nucleotide data. For given structure strings (e.g. secondary structures) it displays single unpaired (loop) and paired (stem) positions after the concatenation process. Optionally, FASconCAT generates NEXUS files of concatenated sequences, either with MrBayes commands directly executable in PAUP * and MrBayes, or without any specific commands. If favoured, FASconCAT dispenses output files in PHYLIP format with relaxed (unlimited signs) or restricted taxon names (up to ten signs) while sequences are printed in non-interleaved format. FASconCAT is implemented in Perl and freely available from http://software.zfmk.de. It runs on UNIX and MS Windows operating systems.
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Affiliation(s)
- Patrick Kück
- Zoologisches Forschungsmuseum Alexander Koenig, Adenauerallee 160, 53113 Bonn, Germany.
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208
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Vidal N, Marin J, Morini M, Donnellan S, Branch WR, Thomas R, Vences M, Wynn A, Cruaud C, Hedges SB. Blindsnake evolutionary tree reveals long history on Gondwana. Biol Lett 2010; 6:558-61. [PMID: 20356885 DOI: 10.1098/rsbl.2010.0220] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Worm-like snakes (scolecophidians) are small, burrowing species with reduced vision. Although largely neglected in vertebrate research, knowledge of their biogeographical history is crucial for evaluating hypotheses of snake origins. We constructed a molecular dataset for scolecophidians with detailed sampling within the largest family, Typhlopidae (blindsnakes). Our results demonstrate that scolecophidians have had a long Gondwanan history, and that their initial diversification followed a vicariant event: the separation of East and West Gondwana approximately 150 Ma. We find that the earliest blindsnake lineages, representing two new families described here, were distributed on the palaeolandmass of India+Madagascar named here as Indigascar. Their later evolution out of Indigascar involved vicariance and several oceanic dispersal events, including a westward transatlantic one, unexpected for burrowing animals. The exceptional diversification of scolecophidians in the Cenozoic was probably linked to a parallel radiation of prey (ants and termites) as well as increased isolation of populations facilitated by their fossorial habits.
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Affiliation(s)
- Nicolas Vidal
- Département Systématique et Evolution, UMR 7138, Muséum National d'Histoire Naturelle, Paris, France.
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209
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Ward PS, Brady SG, Fisher BL, Schultz TR. Phylogeny and biogeography of dolichoderine ants: effects of data partitioning and relict taxa on historical inference. Syst Biol 2010; 59:342-62. [PMID: 20525640 DOI: 10.1093/sysbio/syq012] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ants (Hymenoptera: Formicidae) are conspicuous organisms in most terrestrial ecosystems, often attaining high levels of abundance and diversity. In this study, we investigate the evolutionary history of a major clade of ants, the subfamily Dolichoderinae, whose species frequently achieve ecological dominance in ant communities. This group has also produced some of the world's most successful invasive ants. We use an extensive molecular data set ( approximately 9 kb of sequence data from 10 nuclear genes, covering 48 dolichoderine species and 6 outgroup taxa) to infer the phylogenetic relationships, divergence dates, and biogeographic history of these ants. We evaluate the effects of data partitioning and outgroup composition on phylogenetic inference by estimating relationships under a series of increasingly partitioned data sets and by running analyses both with and without Aneuretus simoni, a rare and localized species that is the nearest living relative of Dolichoderinae. We also examine the effects of excluding 2 data partitions with significant base composition heterogeneity. Our results reveal 4 well-supported and mutually exclusive clades of dolichoderines, corresponding to 4 newly defined tribes: Bothriomyrmecini (B), Dolichoderini (D), Leptomyrmecini (L), and Tapinomini (T). All Bayesian and likelihood analyses yield the same unrooted (ingroup-only) topology, ((D,L),(B,T)), with the outgroups attaching either on the Dolichoderini branch or on the Tapinomini branch. Placement of the root is highly sensitive to choice of model partition and to inclusion/exclusion of Aneuretus. Bayes' factors strongly favor the more partitioned models, and in these Tapinomini is recovered as sister to the remaining dolichoderines, but only if Aneuretus is included. Exclusion of Aneuretus precludes recovery of this topology in all but the most highly partitioned Bayesian analyses and then only with nonsignificant support, underscoring the importance of relict, taxonomically isolated taxa for phylogenetic inference. Removal of 2 partitions with heterogeneous base composition also markedly increases support for placement of the root on the Tapinomini branch. Our divergence date estimates and biogeographic analyses indicate that crown-group dolichoderines arose about 65 million years ago (Ma), although this was preceded by a substantial period (30 million years) of stem group evolution. The 4 extant tribes are estimated to have crown-group origins in the late Paleocene or Eocene (40-60 Ma). Tapinomini and Bothriomyrmecini originated in the Paleotropics and subsequently dispersed to other biogeographic regions. Crown-group Leptomyrmecini arose and diversified in the Neotropics, but they also gave rise to one clade that colonized Australia about 30 Ma and subsequently experienced a massive radiation on that continent. This event occurred later than the diversification of dolichoderines in the northern hemisphere, so that by the time dolichoderines came to dominate the Australian fauna they had already declined in abundance in the Holarctic region.
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Affiliation(s)
- Philip S Ward
- Department of Entomology, University of California, Davis, CA 95616, USA.
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210
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Evans HC, Groden E, Bischoff JF. New fungal pathogens of the red ant, Myrmica rubra, from the UK and implications for ant invasions in the USA. Fungal Biol 2010; 114:451-66. [PMID: 20943156 DOI: 10.1016/j.funbio.2010.03.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Revised: 03/07/2010] [Accepted: 03/08/2010] [Indexed: 10/19/2022]
Abstract
The red ant, Myrmica rubra, is an increasingly invasive pest species in north-eastern USA, where it is known as the European fire ant. During surveys for natural enemies in part of its native range in the UK, three previously unreported fungal pathogens developed on ants when incubated in the laboratory. These are described and illustrated: Paraisaria myrmicarum sp. nov., Hirsutella stilbelliformis var. myrmicarum var. nov., and Hirsutella subramanianii var. myrmicarum var. nov. Based on analyses of the protein coding region EF-1α and LSU rDNA, all three described taxa are shown to be affiliated with the hypocrealean family Ophiocordycipitaceae. The implications for the management of M. rubra in its exotic North American range using classical biological control are discussed.
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Affiliation(s)
- Harry C Evans
- CAB International, E-UK Centre, Bakeham Lane, Egham, Surrey TW209TY, UK.
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211
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Ware JL, Grimaldi DA, Engel MS. The effects of fossil placement and calibration on divergence times and rates: an example from the termites (Insecta: Isoptera). ARTHROPOD STRUCTURE & DEVELOPMENT 2010; 39:204-219. [PMID: 19962450 DOI: 10.1016/j.asd.2009.11.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Revised: 11/24/2009] [Accepted: 11/27/2009] [Indexed: 05/28/2023]
Abstract
Among insects, eusocial behavior occurs in termites, ants, some bees and wasps. Isoptera and Hymenoptera convergently share social behavior, and for both taxa its evolution remains poorly understood. While dating analyses provide researchers with the opportunity to date the origin of eusociality, fossil calibration methodology may mislead subsequent ecological interpretations. Using a comprehensive termite dataset, we explored the effect of fossil placement and calibration methodology. A combined molecular and morphological dataset for 42 extant termite lineages was used, and a second dataset including these 42 taxa, plus an additional 39 fossil lineages for which we had only morphological data. MrBayes doublet-model analyses recovered similar topologies, with one minor exception (Stolotermitidae is sister to the Hodotermitidae, s.s., in the 42-taxon analysis but is in a polytomy with Hodotermitidae and (Kalotermitidae + Neoisoptera) in the 81-taxon analysis). Analyses using the r8s program on these topologies were run with either minimum/maximum constraints (analysis a = 42-taxon and analysis c = 81-taxon analyses) or with the fossil taxon ages fixed (ages fixed to be the geological age of the deposit from which they came, analysis b = 81-taxon analysis). Confidence intervals were determined for the resulting ultrametric trees, and for most major clades there was significant overlap between dates recovered for analyses A and C (with exceptions, such as the nodes Neoisoptera, and Euisoptera). With the exception of isopteran and eusiopteran node ages, however, none of the major clade ages overlapped when analysis B is compared with either analysis A or C. Future studies on Dictyoptera should note that the age of Kalotermitidae was underestimated in absence of kalotermitid fossils with fixed ages.
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Affiliation(s)
- Jessica L Ware
- Division of Invertebrate Zoology, American Museum of Natural History, 81 Street and Central Park West, New York, NY 10024, USA.
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212
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Jansen G, Savolainen R, Vepsäläinen K. Phylogeny, divergence-time estimation, biogeography and social parasite-host relationships of the Holarctic ant genus Myrmica (Hymenoptera: Formicidae). Mol Phylogenet Evol 2010; 56:294-304. [PMID: 20159044 DOI: 10.1016/j.ympev.2010.01.029] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 01/26/2010] [Accepted: 01/27/2010] [Indexed: 10/19/2022]
Abstract
We reconstructed a molecular phylogeny of the ant genus Myrmica, tested reciprocal monophyly of the Nearctic and Palearctic representatives, and inferred social parasite-host relationships for five workerless inquilines and four temporary parasites. We sequenced six gene fragments of 106 specimens (17 not identified to species), analysed the data with Bayesian phylogenetic inference and maximum likelihood, and estimated divergence times using penalized likelihood. Our well resolved phylogeny supported most morphologically defined species groups. The Nearctic and Palearctic species were not reciprocally monophyletic, which suggested repeated species interchange across the Beringian land bridge. Parasitism evolved several times in Myrmica. Three inquilines and one temporary parasite were closest relatives of their host, two inquiline species and one temporary parasite clustered basally to their host(s), and two temporary parasites more distantly. Myrmica probably diversified following drastic climatic cooling at the Eocene-Oligocene boundary ca. 34 Ma, the oldest species groups being rugosa and ritae in central and southeastern Asia. The oldest inquiline, Myrmica karavajevi, was estimated at 17 Ma, the youngest species M. hirsuta at 0.8 Ma, whereas the microgyne of M.rubra is an intraspecific inquiline.
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Affiliation(s)
- Gunther Jansen
- Department of Biosciences, University of Helsinki, Helsinki, Finland.
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213
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Boomsma JJ. Lifetime monogamy and the evolution of eusociality. Philos Trans R Soc Lond B Biol Sci 2010; 364:3191-207. [PMID: 19805427 DOI: 10.1098/rstb.2009.0101] [Citation(s) in RCA: 231] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
All evidence currently available indicates that obligatory sterile eusocial castes only arose via the association of lifetime monogamous parents and offspring. This is consistent with Hamilton's rule (br(s) > r(o)c), but implies that relatedness cancels out of the equation because average relatedness to siblings (r(s)) and offspring (r(o)) are both predictably 0.5. This equality implies that any infinitesimally small benefit of helping at the maternal nest (b), relative to the cost in personal reproduction (c) that persists throughout the lifespan of entire cohorts of helpers suffices to establish permanent eusociality, so that group benefits can increase gradually during, but mostly after the transition. The monogamy window can be conceptualized as a singularity comparable with the single zygote commitment of gametes in eukaryotes. The increase of colony size in ants, bees, wasps and termites is thus analogous to the evolution of multicellularity. Focusing on lifetime monogamy as a universal precondition for the evolution of obligate eusociality simplifies the theory and may help to resolve controversies about levels of selection and targets of adaptation. The monogamy window underlines that cooperative breeding and eusociality are different domains of social evolution, characterized by different sectors of parameter space for Hamilton's rule.
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Affiliation(s)
- Jacobus J Boomsma
- Centre for Social Evolution, Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark.
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214
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Silva RR, Brandão CRF. Morphological patterns and community organization in leaf-litter ant assemblages. ECOL MONOGR 2010. [DOI: 10.1890/08-1298.1] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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215
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Brandão CRF, Diniz JLM, Feitosa RM. The venom apparatus and other morphological characters of the ant Martialis heureka (Hymenoptera, Formicidae, Martialinae). PAPÉIS AVULSOS DE ZOOLOGIA 2010. [DOI: 10.1590/s0031-10492010002600001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We describe and illustrate the venom apparatus and other morphological characters of the recently described Martialis heureka ant worker, a supposedly specialized subterranean predator which could be the sole surviving representative of a highly divergent lineage that arose near the dawn of ant diversification. M. heureka was described as the single species of a genus in the subfamily, Martialinae Rabeling and Verhaagh, known from a single worker. However because the authors had available a unique specimen, dissections and scanning electron microscopy from coated specimens were not possible. We base our study on two worker individuals collected in Manaus, AM, Brazil in 1998 and maintained in 70% alcohol since then; the ants were partially destroyed because of desiccation during transport to São Paulo and subsequent efforts to rescue them from the vial. We were able to recover two left mandibles, two pronota, one dismembered fore coxa, one meso-metapropodeal complex with the median and hind coxae and trochanters still attached, one postpetiole, two gastric tergites, the pygidium and the almost complete venom apparatus (lacking the gonostylus and anal plate). We illustrate and describe the pieces, and compare M. heureka worker morphology with other basal ant subfamilies, concluding it does merit subfamilial status.
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216
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Wernegreen JJ, Kauppinen SN, Brady SG, Ward PS. One nutritional symbiosis begat another: phylogenetic evidence that the ant tribe Camponotini acquired Blochmannia by tending sap-feeding insects. BMC Evol Biol 2009; 9:292. [PMID: 20015388 PMCID: PMC2810300 DOI: 10.1186/1471-2148-9-292] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Accepted: 12/16/2009] [Indexed: 11/28/2022] Open
Abstract
Background Bacterial endosymbiosis has a recurring significance in the evolution of insects. An estimated 10-20% of insect species depend on bacterial associates for their nutrition and reproductive viability. Members of the ant tribe Camponotini, the focus of this study, possess a stable, intracellular bacterial mutualist. The bacterium, Blochmannia, was first discovered in Camponotus and has since been documented in a distinct subgenus of Camponotus, Colobopsis, and in the related genus Polyrhachis. However, the distribution of Blochmannia throughout the Camponotini remains in question. Documenting the true host range of this bacterial mutualist is an important first step toward understanding the various ecological contexts in which it has evolved, and toward identifying its closest bacterial relatives. In this study, we performed a molecular screen, based on PCR amplification of 16S rDNA, to identify bacterial associates of diverse Camponotini species. Results Phylogenetic analyses of 16S rDNA gave four important insights: (i) Blochmannia occurs in a broad range of Camponotini genera including Calomyrmex, Echinopla, and Opisthopsis, and did not occur in outgroups related to this tribe (e.g., Notostigma). This suggests that the mutualism originated in the ancestor of the tribe Camponotini. (ii) The known bacteriocyte-associated symbionts of ants, in Formica, Plagiolepis, and the Camponotini, arose independently. (iii) Blochmannia is nestled within a diverse clade of endosymbionts of sap-feeding hemipteran insects, such as mealybugs, aphids, and psyllids. In our analyses, a group of secondary symbionts of mealybugs are the closest relatives of Blochmannia. (iv) Blochmannia has cospeciated with its known hosts, although deep divergences at the genus level remain uncertain. Conclusions The Blochmannia mutualism occurs in Calomyrmex, Echinopla, and Opisthopsis, in addition to Camponotus, and probably originated in the ancestral lineage leading to the Camponotini. This significant expansion of its known host range implies that the mutualism is more ancient and ecologically diverse than previously documented. Blochmannia is most closely related to endosymbionts of sap-feeding hemipterans, which ants tend for their carbohydrate-rich honeydew. Based on phylogenetic results, we propose Camponotini might have originally acquired this bacterial mutualist through a nutritional symbiosis with other insects.
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Affiliation(s)
- Jennifer J Wernegreen
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA 02543, USA.
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217
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Russell JA, Moreau CS, Goldman-Huertas B, Fujiwara M, Lohman DJ, Pierce NE. Bacterial gut symbionts are tightly linked with the evolution of herbivory in ants. Proc Natl Acad Sci U S A 2009; 106:21236-41. [PMID: 19948964 PMCID: PMC2785723 DOI: 10.1073/pnas.0907926106] [Citation(s) in RCA: 232] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Indexed: 11/18/2022] Open
Abstract
Ants are a dominant feature of terrestrial ecosystems, yet we know little about the forces that drive their evolution. Recent findings illustrate that their diets range from herbivorous to predaceous, with "herbivores" feeding primarily on exudates from plants and sap-feeding insects. Persistence on these nitrogen-poor food sources raises the question of how ants obtain sufficient nutrition. To investigate the potential role of symbiotic microbes, we have surveyed 283 species from 18 of the 21 ant subfamilies using molecular techniques. Our findings uncovered a wealth of bacteria from across the ants. Notable among the surveyed hosts were herbivorous "turtle ants" from the related genera Cephalotes and Procryptocerus (tribe Cephalotini). These commonly harbored bacteria from ant-specific clades within the Burkholderiales, Pseudomonadales, Rhizobiales, Verrucomicrobiales, and Xanthomonadales, and studies of lab-reared Cephalotes varians characterized these microbes as symbiotic residents of ant guts. Although most of these symbionts were confined to turtle ants, bacteria from an ant-specific clade of Rhizobiales were more broadly distributed. Statistical analyses revealed a strong relationship between herbivory and the prevalence of Rhizobiales gut symbionts within ant genera. Furthermore, a consideration of the ant phylogeny identified at least five independent origins of symbioses between herbivorous ants and related Rhizobiales. Combined with previous findings and the potential for symbiotic nitrogen fixation, our results strongly support the hypothesis that bacteria have facilitated convergent evolution of herbivory across the ants, further implicating symbiosis as a major force in ant evolution.
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Affiliation(s)
- Jacob A. Russell
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138
- Department of Biology, Drexel University, Philadelphia, PA 19104
| | - Corrie S. Moreau
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138
- Department of Zoology, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL 60605; and
| | - Benjamin Goldman-Huertas
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138
| | - Mikiko Fujiwara
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138
| | - David J. Lohman
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138
- Department of Biology, The City College of The City University of New York, Convent Avenue at 138th Street, New York, NY 10031
| | - Naomi E. Pierce
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138
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218
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Lessard JP, Fordyce JA, Gotelli NJ, Sanders NJ. Invasive ants alter the phylogenetic structure of ant communities. Ecology 2009; 90:2664-9. [PMID: 19886475 DOI: 10.1890/09-0503.1] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Invasive species displace native species and potentially alter the structure and function of ecological communities. In this study, we compared the generic composition of intact and invaded ant communities from 12 published studies and found that invasive ant species alter the phylogenetic structure of native ant communities. Intact ant communities were phylogenetically evenly dispersed, suggesting that competition structures communities. However, in the presence of an invasive ant species, these same communities were phylogenetically clustered. Phylogenetic clustering in invaded communities suggests that invasive species may act as strong environmental filters and prune the phylogenetic tree of native species in a nonrandom manner, such that only a few closely related taxa can persist in the face of a biological invasion. Taxa that were displaced by invasive ant species were evenly dispersed in the phylogeny, suggesting that diversity losses from invasive ant species are not clustered in particular lineages. Collectively, these results suggest that there is strong phylogenetic structuring in intact native ant communities, but the spread of invasive species disassembles those communities above and beyond the effect of simple reductions in diversity.
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Affiliation(s)
- Jean-Philippe Lessard
- Department of Ecology and Evolutionary Biology, 569 Dabney Hall, University of Tennessee, Knoxville, Tennessee 37996, USA.
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219
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Abstract
A recent workshop held at the Arizona State University Center for Social Dynamics and Complexity gathered over 50 prominent researchers from around the globe to discuss the development of genomic resources for several ant species. Ants play crucial roles in many ecological niches and the sequencing of several ant genomes promises to elucidate topics ranging from the genetic basis for social complexity, longevity and behaviour to systems biology and the identification of novel antimicrobial compounds. Unlike other species, most ant genomes are being generated by individual labs and small collaborations without the annotation and computational resources that support prominent model organism genome databases such those for the fruitfly and roundworm. Attendees summarized their current progress and future plans for several ant genomes and discussed how best to coordinate the analysis and annotation of ant sequences to benefit the broad research interests of the social insect community.
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Jansen G, Savolainen R, Vepsäläinen K. DNA barcoding as a heuristic tool for classifying undescribed NearcticMyrmicaants (Hymenoptera: Formicidae). ZOOL SCR 2009. [DOI: 10.1111/j.1463-6409.2009.00386.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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222
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MOLET MATHIEU, FISHER BRIANL, ITO FUMINORI, PEETERS CHRISTIAN. Shift from independent to dependent colony foundation and evolution of ‘multi-purpose’ ergatoid queens in Mystrium ants (subfamily Amblyoponinae). Biol J Linn Soc Lond 2009. [DOI: 10.1111/j.1095-8312.2009.01257.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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223
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Bradley TJ, Briscoe AD, Brady SG, Contreras HL, Danforth BN, Dudley R, Grimaldi D, Harrison JF, Kaiser JA, Merlin C, Reppert SM, Vandenbrooks JM, Yanoviak SP. Episodes in insect evolution. Integr Comp Biol 2009; 49:590-606. [PMID: 21665843 DOI: 10.1093/icb/icp043] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This article derives from a society-wide symposium organized by Timothy Bradley and Adriana Briscoe and presented at the 2009 annual meeting of the Society for Integrative and Comparative Biology in Boston, Massachusetts. David Grimaldi provided the opening presentation in which he outlined the major evolutionary events in the formation and subsequent diversification of the insect clade. This presentation was followed by speakers who detailed the evolutionary history of specific physiological and/or behavioral traits that have caused insects to be both ecologically successful and fascinating as subjects for biological study. These include a review of the evolutionary history of the insects, the origins of flight, osmoregulation, the evolution of tracheal systems, the evolution of color vision, circadian clocks, and the evolution of eusociality. These topics, as covered by the speakers, provide an overview of the pattern and timing of evolutionary diversification and specialization in the group of animals we know as insects.
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Affiliation(s)
- Timothy J Bradley
- *Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, CA 92697-2525, USA;Department of Entomology and Laboratories of Analytical Biology, National Museum of the Smithsonian Institution, Washington, D.C. 20013-7012, USA;Department of Entomology, Cornell University, Ithaca, NY 14853, USA;Department of Integrative Biology, University of California Berkeley, Berkeley, CA 94720, USA;Division of Invertebrate Zoology, Museum of Natural History, New York, NY 10024, USA;Section of Organismal, Integrative and Systems Biology, School of Life Sciences, Arizona State University, Tempe AZ 85287-4501, USA;Department of Basic Sciences, Midwestern University, Glendale, AZ 85308, USA;Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA;Department of Biology, University of Arkansas Little Rock, Little Rock, AR 72204, USA
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Asplen MK, Whitfield JB, DE Boer JG, Heimpel GE. Ancestral state reconstruction analysis of hymenopteran sex determination mechanisms. J Evol Biol 2009; 22:1762-9. [PMID: 19555444 DOI: 10.1111/j.1420-9101.2009.01774.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We provide the first phylogenetic evidence supporting complementary sex determination (CSD) as the ancestral mechanism for haplodiploidy in the Hymenoptera. It is currently not possible, however, to distinguish the evolutionary polarity of single locus (sl) CSD and multiple-locus (ml) CSD given the available data. In this light, we discuss the seemingly maladaptive hypothesis of ml-CSD ancestry, suggesting that collapse from ml-CSD to sl-CSD should remain a viable evolutionary hypothesis based on (i) likely weakening of frequency-dependent selection on sex alleles under ml-CSD and (ii) recent findings with respect to the evolutionary novelty of the complementary sex determiner gene in honeybees. Our findings help provide a phylogenetically informed blueprint for future sampling of sex determination mechanisms in the Hymenoptera, as they yield hypotheses for many unsampled or ambiguous taxa and highlight taxa whose further sampling will influence reconstruction of the evolutionary polarity of sex determination mechanisms in major clades.
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Affiliation(s)
- M K Asplen
- Department of Entomology, University of Minnesota, St. Paul, MN 55108, USA.
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225
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Helanterä H, Strassmann JE, Carrillo J, Queller DC. Unicolonial ants: where do they come from, what are they and where are they going? Trends Ecol Evol 2009; 24:341-9. [DOI: 10.1016/j.tree.2009.01.013] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Revised: 01/05/2009] [Accepted: 01/05/2009] [Indexed: 11/15/2022]
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226
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Bacci M, Solomon SE, Mueller UG, Martins VG, Carvalho AO, Vieira LG, Silva-Pinhati ACO. Phylogeny of leafcutter ants in the genus Atta Fabricius (Formicidae: Attini) based on mitochondrial and nuclear DNA sequences. Mol Phylogenet Evol 2009; 51:427-37. [DOI: 10.1016/j.ympev.2008.11.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 10/24/2008] [Accepted: 11/06/2008] [Indexed: 10/21/2022]
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227
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Pohl N, Sison-Mangus MP, Yee EN, Liswi SW, Briscoe AD. Impact of duplicate gene copies on phylogenetic analysis and divergence time estimates in butterflies. BMC Evol Biol 2009; 9:99. [PMID: 19439087 PMCID: PMC2689175 DOI: 10.1186/1471-2148-9-99] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Accepted: 05/13/2009] [Indexed: 12/05/2022] Open
Abstract
Background The increase in availability of genomic sequences for a wide range of organisms has revealed gene duplication to be a relatively common event. Encounters with duplicate gene copies have consequently become almost inevitable in the context of collecting gene sequences for inferring species trees. Here we examine the effect of incorporating duplicate gene copies evolving at different rates on tree reconstruction and time estimation of recent and deep divergences in butterflies. Results Sequences from ultraviolet-sensitive (UVRh), blue-sensitive (BRh), and long-wavelength sensitive (LWRh) opsins,EF-1α and COI were obtained from 27 taxa representing the five major butterfly families (5535 bp total). Both BRh and LWRh are present in multiple copies in some butterfly lineages and the different copies evolve at different rates. Regardless of the phylogenetic reconstruction method used, we found that analyses of combined data sets using either slower or faster evolving copies of duplicate genes resulted in a single topology in agreement with our current understanding of butterfly family relationships based on morphology and molecules. Interestingly, individual analyses of BRh and LWRh sequences also recovered these family-level relationships. Two different relaxed clock methods resulted in similar divergence time estimates at the shallower nodes in the tree, regardless of whether faster or slower evolving copies were used, with larger discrepancies observed at deeper nodes in the phylogeny. The time of divergence between the monarch butterfly Danaus plexippus and the queen D. gilippus (15.3–35.6 Mya) was found to be much older than the time of divergence between monarch co-mimic Limenitis archippus and red-spotted purple L. arthemis (4.7–13.6 Mya), and overlapping with the time of divergence of the co-mimetic passionflower butterflies Heliconius erato and H. melpomene (13.5–26.1 Mya). Our family-level results are congruent with recent estimates found in the literature and indicate an age of 84–113 million years for the divergence of all butterfly families. Conclusion These results are consistent with diversification of the butterfly families following the radiation of angiosperms and suggest that some classes of opsin genes may be usefully employed for both phylogenetic reconstruction and divergence time estimation.
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Affiliation(s)
- Nélida Pohl
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.
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228
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Viljakainen L, Pamilo P. Selection on an antimicrobial peptide defensin in ants. J Mol Evol 2009; 67:643-52. [PMID: 18956133 DOI: 10.1007/s00239-008-9173-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Accepted: 10/06/2008] [Indexed: 11/26/2022]
Abstract
Ants live in crowded nests with interacting individuals, which makes them particularly prone to infectious diseases. The question is, how do ants cope with the increased risk of pathogen transmission due to sociality? We have studied the molecular evolution of defensin, a gene encoding an antimicrobial protein, in ants. Defensin sequences from several ant species were analyzed with maximum likelihood models of codon substitution to infer selection. Positive selection was detected in the mature region of defensin, whereas the signal and pro regions seem to be evolving neutrally. We also found a significantly higher rate of nonsynonymous substitutions in some phylogenetic lineages, as well as dN/dS >1, suggesting varying selection pressures in different lineages. Earlier studies on the molecular evolution of insect antimicrobial peptide genes have focused on termites and dipteran species, and detected positive selection only in duplicated termicin genes in termites. These findings, together with our present results, provide an indication that the immune systems of social insects (ants and termites) and dipteran insects may have responded differently to the selection pressure caused by microbial pathogens.
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Affiliation(s)
- Lumi Viljakainen
- Department of Biology and Biocenter Oulu, University of Oulu, P.O. Box 3000, Oulu 90014, Finland.
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229
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Viljakainen L, Evans JD, Hasselmann M, Rueppell O, Tingek S, Pamilo P. Rapid Evolution of Immune Proteins in Social Insects. Mol Biol Evol 2009; 26:1791-801. [DOI: 10.1093/molbev/msp086] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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230
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Dunn RR, Agosti D, Andersen AN, Arnan X, Bruhl CA, Cerdá X, Ellison AM, Fisher BL, Fitzpatrick MC, Gibb H, Gotelli NJ, Gove AD, Guenard B, Janda M, Kaspari M, Laurent EJ, Lessard JP, Longino JT, Majer JD, Menke SB, McGlynn TP, Parr CL, Philpott SM, Pfeiffer M, Retana J, Suarez AV, Vasconcelos HL, Weiser MD, Sanders NJ. Climatic drivers of hemispheric asymmetry in global patterns of ant species richness. Ecol Lett 2009; 12:324-33. [DOI: 10.1111/j.1461-0248.2009.01291.x] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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231
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Reproductive constraint is a developmental mechanism that maintains social harmony in advanced ant societies. Proc Natl Acad Sci U S A 2008; 105:17884-9. [PMID: 19004767 DOI: 10.1073/pnas.0807351105] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A hallmark of eusociality in ants is the reproductive division of labor between queens and workers. Yet, nothing is known about the molecular mechanisms underlying reproduction in this group. We therefore compared the developmental genetic capacity of queens and workers to reproduce in several eusocially advanced species from the two largest subfamilies of ants, the Myrmicinae and Formicinae. In flies, the asymmetric localization of maternally encoded determinants (mRNAs and proteins) during oogenesis establishes oocyte polarity and subsequently ensures proper embryonic development. Vasa and nanos, two key maternal determinants, are properly localized in the posterior of queen oocytes, but their localization is impaired in those of the workers. This mislocalization leads to severe embryonic defects in worker progeny, and therefore, represents a constraint on worker reproduction that we call 'reproductive constraint.' We show that reproductive constraint is phylogenetically widespread, and is at high levels in most species tested. Reproductive constraint can simultaneously reduce or eliminate the workers' ability to produce viable eggs for reproduction, while preserving their ability to produce trophic eggs for nutrition, and thus, may have been the basis for the evolutionary retention of worker ovaries in the majority of ants. We propose that high levels of reproductive constraint has most likely evolved as a consequence of selection at the colony level to reduce or eliminate any potential conflict over worker reproduction, therefore maintaining harmony and colony efficiency in advanced ant societies.
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232
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Smith CR, Anderson KE, Tillberg CV, Gadau J, Suarez AV. Caste determination in a polymorphic social insect: nutritional, social, and genetic factors. Am Nat 2008; 172:497-507. [PMID: 18707530 DOI: 10.1086/590961] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
We examined how dietary, social, and genetic factors affect individual size and caste in the Florida harvester ant Pogonomyrmex badius, which has three discrete female castes. The diet that a larva consumed, as indicated by delta(13)C, delta(15)N, and C:N, varied with caste. Both N content and estimated trophic position of dietary input was higher for major than for minor workers and was highest for gynes (reproductive females). The size and resources of a colony affected the size of only minor workers, not that of gynes and major workers. Approximately 19% of patrilines showed a bias in which female caste they produced. There were significant genetic effects on female size, and the average sizes of a major worker and a gyne produced by a patriline were correlated, but neither was correlated with minor worker size. Thus, genetic factors influence both caste and size within caste. We conclude that environmental, social, and genetic variation interact to create morphological and physiological variation among females in P. badius. However, the relative importance of each type of factor affecting caste determination is caste specific.
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Affiliation(s)
- C R Smith
- Program in Ecology and Evolutionary Biology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, USA.
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233
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Kikuchi T, Miyazaki S, Ohnishi H, Takahashi J, Nakajima Y, Tsuji K. Small queens and big-headed workers in a monomorphic ponerine ant. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2008; 95:963-8. [PMID: 18581088 DOI: 10.1007/s00114-008-0414-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2007] [Revised: 05/22/2008] [Accepted: 05/26/2008] [Indexed: 10/21/2022]
Abstract
Evolution of caste is a central issue in the biology of social insects. Comparative studies on their morphology so far suggest the following three patterns: (1) a positive correlation between queen-worker size dimorphism and the divergence in reproductive ability between castes, (2) a negative correlation among workers between morphological diversity and reproductive ability, and (3) a positive correlation between queen-worker body shape difference and the diversity in worker morphology. We conducted morphological comparisons between castes in Pachycondyla luteipes, workers of which are monomorphic and lack their reproductive ability. Although the size distribution broadly overlapped, mean head width, head length, and scape length were significantly different between queens and workers. Conversely, in eye length, petiole width, and Weber's length, the size differences were reversed. The allometries (head length/head width, scape length/head width, and Weber's length/head width) were also significantly different between queens and workers. Morphological examinations showed that the body shape was different between queens and workers, and the head part of workers was disproportionately larger than that of queens. This pattern of queen-worker dimorphism is novel in ants with monomorphic workers and a clear exception to the last pattern. This study suggests that it is possible that the loss of individual-level selection, the lack of reproductive ability, influences morphological modification in ants.
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Affiliation(s)
- Tomonori Kikuchi
- Faculty of Agriculture, University of the Ryukyus, Okinawa, Japan.
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234
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Smith CR, Toth AL, Suarez AV, Robinson GE. Genetic and genomic analyses of the division of labour in insect societies. Nat Rev Genet 2008; 9:735-48. [PMID: 18802413 DOI: 10.1038/nrg2429] [Citation(s) in RCA: 228] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Division of labour--individuals specializing in different activities--features prominently in the spectacular success of the social insects. Until recently, genetic and genomic analyses of division of labour were limited to just a few species. However, research on an ever-increasing number of species has provided new insight, from which we highlight two results. First, heritable influences on division of labour are more pervasive than previously imagined. Second, different forms of division of labour, in lineages in which eusociality has arisen independently, have evolved through changes in the regulation of highly conserved molecular pathways associated with several basic life-history traits, including nutrition, metabolism and reproduction.
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Affiliation(s)
- Chris R Smith
- Program in Ecology and Evolutionary Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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235
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Rabeling C, Brown JM, Verhaagh M. Newly discovered sister lineage sheds light on early ant evolution. Proc Natl Acad Sci U S A 2008; 105:14913-7. [PMID: 18794530 PMCID: PMC2567467 DOI: 10.1073/pnas.0806187105] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Indexed: 11/18/2022] Open
Abstract
Ants are the world's most conspicuous and important eusocial insects and their diversity, abundance, and extreme behavioral specializations make them a model system for several disciplines within the biological sciences. Here, we report the discovery of a new ant that appears to represent the sister lineage to all extant ants (Hymenoptera: Formicidae). The phylogenetic position of this cryptic predator from the soils of the Amazon rainforest was inferred from several nuclear genes, sequenced from a single leg. Martialis heureka (gen. et sp. nov.) also constitutes the sole representative of a new, morphologically distinct subfamily of ants, the Martialinae (subfam. nov.). Our analyses have reduced the likelihood of long-branch attraction artifacts that have troubled previous phylogenetic studies of early-diverging ants and therefore solidify the emerging view that the most basal extant ant lineages are cryptic, hypogaeic foragers. On the basis of morphological and phylogenetic evidence we suggest that these specialized subterranean predators are the sole surviving representatives of a highly divergent lineage that arose near the dawn of ant diversification and have persisted in ecologically stable environments like tropical soils over great spans of time.
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Affiliation(s)
- Christian Rabeling
- Section of Integrative Biology, University of Texas, 1 University Station C0930, Austin, TX 78712, USA.
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236
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Abstract
Ants and termites are the most abundant animals on earth. Their ecological success is attributed to their social life. They live in colonies consisting of few reproducing individuals, while the large majority of colony members (workers/soldiers) forego reproduction at least temporarilly. Despite their apparent resemblance in social organisation, both groups evolved social life independently. Termites are basically social cockroaches, while ants evolved from predatory wasps. In this review, I will concentrate on termites with an ancestral life type, the wood-dwelling termites, to compare them with ants. Their different ancestries provided both groups with different life history pre-adaptations for social evolution. Like their closest relatives, the woodroaches, wood-dwelling termites live inside their food, a piece of wood. Thus, intensive costly food provisioning of their young is not necessary, especially as young instars are rather independent due to their hemimetabolous development. In contrast, ants are progressive food provisioners which have to care intensively for their helpless brood. Corresponding to the precocial – altricial analogy, helping by workers is selected in ants, while new evidence suggests that wood-dwelling termite workers are less engaged in brood care. Rather they seem to stay in the nest because there is generally low selection for dispersal. The nest presents a safe haven with no local resource competition as long as food is abundant (which is generally the case), while founding a new colony is very risky. Despite these differences between ants and termites, their common dwelling life style resulted in convergent evolution, especially winglessness, that probably accounts for the striking similarity between both groups. In ants, all workers are wingless and winglessness in sexuals evolved in several taxa as a derived trait. In wood-dwelling termites, workers are by default wingless as they are immatures. These immatures can develop into winged sexuals that disperse and found a new nest or into neotenic replacement reproductives that inherit the natal colony. Depending on the worker instar from which the latter develop, the neotenic reproductives are either apterous or brachypterous, but never winged. I propose that this wing polyphenism might present a basis for the evolution of social life in termites.
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237
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Pilgrim EM, von Dohlen CD, Pitts JP. Molecular phylogenetics of Vespoidea indicate paraphyly of the superfamily and novel relationships of its component families and subfamilies. ZOOL SCR 2008. [DOI: 10.1111/j.1463-6409.2008.00340.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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238
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Maruyama M, Steiner FM, Stauffer C, Akino T, Crozier RH, Schlick-Steiner BC. A DNA and morphology based phylogenetic framework of the ant genus Lasius with hypotheses for the evolution of social parasitism and fungiculture. BMC Evol Biol 2008; 8:237. [PMID: 18710580 PMCID: PMC2542377 DOI: 10.1186/1471-2148-8-237] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Accepted: 08/19/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ants of the genus Lasius are ecologically important and an important system for evolutionary research. Progress in evolutionary research has been hindered by the lack of a well-founded phylogeny of the subgenera, with three previous attempts disagreeing. Here we employed two mitochondrial genes (cytochrome c oxidase subunit I, 16S ribosomal RNA), comprising 1,265 bp, together with 64 morphological characters, to recover the phylogeny of Lasius by Bayesian and Maximum Parsimony inference after exploration of potential causes of phylogenetic distortion. We use the resulting framework to infer evolutionary pathways for social parasitism and fungiculture. RESULTS We recovered two well supported major lineages. One includes Acanthomyops, Austrolasius, Chthonolasius, and Lasius pallitarsis, which we confirm to represent a seventh subgenus, the other clade contains Dendrolasius, and Lasius sensu stricto. The subgenus Cautolasius, displaying neither social parasitism nor fungiculture, probably belongs to the second clade, but its phylogenetic position is not resolved at the cutoff values of node support we apply. Possible causes for previous problems with reconstructing the Lasius phylogeny include use of other reconstruction techniques, possibly more prone to instabilities in some instances, and the inclusion of phylogenetically distorting characters. CONCLUSION By establishing an updated phylogenetic framework, our study provides the basis for a later formal taxonomic revision of subgenera and for studying the evolution of various ecologically and sociobiologically relevant traits of Lasius, although there is need for future studies to include nuclear genes and additional samples from the Nearctic. Both social parasitism and fungiculture evolved twice in Lasius, once in each major lineage, which opens up new opportunities for comparative analyses. The repeated evolution of social parasitism has been established for other groups of ants, though not for temporary social parasitism as found in Lasius. For fungiculture, the independent emergence twice in a monophyletic group marks a novel scenario in ants. We present alternative hypotheses for the evolution of both traits, with one of each involving loss of the trait. Though less likely for both traits than later evolution without reversal, we consider reversal as sufficiently plausible to merit independent testing.
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Affiliation(s)
- Munetoshi Maruyama
- Department of Zoology, National Science Museum, Hyakunin-chô 3-23-1, Shinjuku-ku, Tokyo 169-0073, Japan.
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Gobin B, Ito F, Billen J, Peeters C. Degeneration of sperm reservoir and the loss of mating ability in worker ants. Naturwissenschaften 2008; 95:1041-8. [DOI: 10.1007/s00114-008-0420-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Revised: 06/12/2008] [Accepted: 06/19/2008] [Indexed: 11/24/2022]
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241
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Unraveling the evolutionary history of the hyperdiverse ant genus Pheidole (Hymenoptera: Formicidae). Mol Phylogenet Evol 2008; 48:224-39. [DOI: 10.1016/j.ympev.2008.02.020] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Revised: 01/18/2008] [Accepted: 02/04/2008] [Indexed: 11/20/2022]
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Fisher BL, Smith MA. A revision of Malagasy species of Anochetus mayr and Odontomachus latreille (Hymenoptera: Formicidae). PLoS One 2008; 3:e1787. [PMID: 18509544 PMCID: PMC2387237 DOI: 10.1371/journal.pone.0001787] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Accepted: 02/11/2008] [Indexed: 11/18/2022] Open
Abstract
Species inventories are essential for documenting global diversity and generating necessary material for taxonomic study and conservation planning. However, for inventories to be immediately relevant, the taxonomic process must reduce the time to describe and identify specimens. To address these concerns for the inventory of arthropods across the Malagasy region, we present here a collaborative approach to taxonomy where collectors, morphologists and DNA barcoders using cytochrome c oxidase 1 (CO1) participate collectively in a team-driven taxonomic process. We evaluate the role of DNA barcoding as a tool to accelerate species identification and description. This revision is primarily based on arthropod surveys throughout the Malagasy region from 1992 to 2006. The revision is based on morphological and CO1 DNA barcode analysis of 500 individuals. In the region, five species of Anochetus (A. boltonisp. nov., A. goodmanisp. nov., A. grandidieri, and A. madagascarensis from Madagascar, and A. pattersonisp. nov. from Seychelles) and three species of Odontomachus (O. coquereli, O. troglodytes and O. simillimus) are recognized. DNA barcoding (using cytochrome c oxidase 1 (CO1)) facilitated caste association and type designation, and highlighted population structure associated with reproductive strategy, biogeographic and evolutionary patterns for future exploration. This study provides an example of collaborative taxonomy, where morphology is combined with DNA barcoding. We demonstrate that CO1 DNA barcoding is a practical tool that allows formalized alpha-taxonomy at a speed, detail, precision, and scale unattainable by employing morphology alone.
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Affiliation(s)
- Brian L. Fisher
- Department of Entomology, California Academy of Sciences, San Francisco, California, United States of America
| | - M. Alex Smith
- Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario, Canada
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Wild AL, Maddison DR. Evaluating nuclear protein-coding genes for phylogenetic utility in beetles. Mol Phylogenet Evol 2008; 48:877-91. [PMID: 18644735 DOI: 10.1016/j.ympev.2008.05.023] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2007] [Revised: 04/29/2008] [Accepted: 05/20/2008] [Indexed: 10/22/2022]
Abstract
Although nuclear protein-coding genes have proven broadly useful for phylogenetic inference, relatively few such genes are regularly employed in studies of Coleoptera, the most diverse insect order. We increase the number of loci available for beetle systematics by developing protocols for three genes previously unused in beetles (alpha-spectrin, RNA polymerase II and topoisomerase I) and by refining protocols for five genes already in use (arginine kinase, CAD, enolase, PEPCK and wingless). We evaluate the phylogenetic performance of each gene in a Bayesian framework against a presumably known test phylogeny. The test phylogeny covers 31 beetle specimens and two outgroup taxa of varying age, including three of the four extant beetle suborders and a denser sampling in Adephaga and in the carabid genus Bembidion. All eight genes perform well for Cenozoic divergences and accurately separate closely related species within Bembidion, but individual genes differ markedly in accuracy over the older Mesozoic and Permian divergences. The concatenated data reconstruct the test phylogeny with high support in both Bayesian and parsimony analyses, indicating that combining data from multiple nuclear loci will be a fruitful approach for assembling the beetle tree of life.
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Affiliation(s)
- Alexander L Wild
- Department of Entomology, University of Arizona, Tucson, AZ 85721, USA.
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244
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Page RDM. Biodiversity informatics: the challenge of linking data and the role of shared identifiers. Brief Bioinform 2008; 9:345-54. [PMID: 18445641 DOI: 10.1093/bib/bbn022] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A major challenge facing biodiversity informatics is integrating data stored in widely distributed databases. Initial efforts have relied on taxonomic names as the shared identifier linking records in different databases. However, taxonomic names have limitations as identifiers, being neither stable nor globally unique, and the pace of molecular taxonomic and phylogenetic research means that a lot of information in public sequence databases is not linked to formal taxonomic names. This review explores the use of other identifiers, such as specimen codes and GenBank accession numbers, to link otherwise disconnected facts in different databases. The structure of these links can also be exploited using the PageRank algorithm to rank the results of searches on biodiversity databases. The key to rich integration is a commitment to deploy and reuse globally unique, shared identifiers [such as Digital Object Identifiers (DOIs) and Life Science Identifiers (LSIDs)], and the implementation of services that link those identifiers.
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Affiliation(s)
- Roderic D M Page
- Division of Environmental and Evolutional Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
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Hughes WOH, Ratnieks FLW, Oldroyd BP. Multiple paternity or multiple queens: two routes to greater intracolonial genetic diversity in the eusocial Hymenoptera. J Evol Biol 2008; 21:1090-5. [PMID: 18422530 DOI: 10.1111/j.1420-9101.2008.01532.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Understanding the evolution of multiple mating by females (polyandry) is an important question in behavioural ecology. Most leading explanations for polyandry by social insect queens are based upon a postulated fitness benefit from increased intracolonial genetic diversity, which also arises when colonies are headed by multiple queens (polygyny). An indirect test of the genetic diversity hypotheses is therefore provided by the relationship between polyandry and polygyny across species, which should be negative if the genetic diversity hypotheses are correct. Here, we conduct a powerful comparative investigation of the relationship between polyandry and polygyny for 241 species of eusocial Hymenoptera (ants, bees and wasps). We find a clear and significant negative relationship between polyandry and polygyny after controlling for phylogeny. These results strongly suggest that fitness benefits resulting from increased intracolonial genetic diversity have played an important role in the evolution of polyandry, and possibly polygyny, in social insects.
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Affiliation(s)
- W O H Hughes
- Institute of Integrative and Comparative Biology, University of Leeds, Leeds, UK.
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246
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Abstract
Agriculture is a specialized form of symbiosis that is known to have evolved in only four animal groups: humans, bark beetles, termites, and ants. Here, we reconstruct the major evolutionary transitions that produced the five distinct agricultural systems of the fungus-growing ants, the most well studied of the nonhuman agriculturalists. We do so with reference to the first fossil-calibrated, multiple-gene, molecular phylogeny that incorporates the full range of taxonomic diversity within the fungus-growing ant tribe Attini. Our analyses indicate that the original form of ant agriculture, the cultivation of a diverse subset of fungal species in the tribe Leucocoprineae, evolved approximately 50 million years ago in the Neotropics, coincident with the early Eocene climatic optimum. During the past 30 million years, three known ant agricultural systems, each involving a phylogenetically distinct set of derived fungal cultivars, have separately arisen from the original agricultural system. One of these derived systems subsequently gave rise to the fifth known system of agriculture, in which a single fungal species is cultivated by leaf-cutter ants. Leaf-cutter ants evolved remarkably recently ( approximately 8-12 million years ago) to become the dominant herbivores of the New World tropics. Our analyses identify relict, extant attine ant species that occupy phylogenetic positions that are transitional between the agricultural systems. Intensive study of those species holds particular promise for clarifying the sequential accretion of ecological and behavioral characters that produced each of the major ant agricultural systems.
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247
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Tsutsui ND, Suarez AV, Spagna JC, Johnston JS. The evolution of genome size in ants. BMC Evol Biol 2008; 8:64. [PMID: 18302783 PMCID: PMC2268675 DOI: 10.1186/1471-2148-8-64] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Accepted: 02/26/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Despite the economic and ecological importance of ants, genomic tools for this family (Formicidae) remain woefully scarce. Knowledge of genome size, for example, is a useful and necessary prerequisite for the development of many genomic resources, yet it has been reported for only one ant species (Solenopsis invicta), and the two published estimates for this species differ by 146.7 Mb (0.15 pg). RESULTS Here, we report the genome size for 40 species of ants distributed across 10 of the 20 currently recognized subfamilies, thus making Formicidae the 4th most surveyed insect family and elevating the Hymenoptera to the 5th most surveyed insect order. Our analysis spans much of the ant phylogeny, from the less derived Amblyoponinae and Ponerinae to the more derived Myrmicinae, Formicinae and Dolichoderinae. We include a number of interesting and important taxa, including the invasive Argentine ant (Linepithema humile), Neotropical army ants (genera Eciton and Labidus), trapjaw ants (Odontomachus), fungus-growing ants (Apterostigma, Atta and Sericomyrmex), harvester ants (Messor, Pheidole and Pogonomyrmex), carpenter ants (Camponotus), a fire ant (Solenopsis), and a bulldog ant (Myrmecia). Our results show that ants possess small genomes relative to most other insects, yet genome size varies three-fold across this insect family. Moreover, our data suggest that two whole-genome duplications may have occurred in the ancestors of the modern Ectatomma and Apterostigma. Although some previous studies of other taxa have revealed a relationship between genome size and body size, our phylogenetically-controlled analysis of this correlation did not reveal a significant relationship. CONCLUSION This is the first analysis of genome size in ants (Formicidae) and the first across multiple species of social insects. We show that genome size is a variable trait that can evolve gradually over long time spans, as well as rapidly, through processes that may include occasional whole-genome duplication. The small genome sizes of ants, combined with their ecological, evolutionary and agricultural importance, suggest that some of these species may be good candidates for future whole-genome sequencing projects.
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Affiliation(s)
- Neil D Tsutsui
- Department of Environmental Science, Policy and Management, University of California-Berkeley, Berkeley, CA 94720, USA
| | - Andrew V Suarez
- Department of Animal Biology and Department of Entomology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
- Institute for Genomic Biology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
| | - Joseph C Spagna
- Department of Animal Biology and Department of Entomology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
- Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
| | - J Spencer Johnston
- Department of Entomology, Texas A&M University, College Station, TX 77843-2475, USA
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Chenoweth LB, Tierney SM, Smith JA, Cooper SJB, Schwarz MP. Social complexity in bees is not sufficient to explain lack of reversions to solitary living over long time scales. BMC Evol Biol 2007; 7:246. [PMID: 18154646 PMCID: PMC2231370 DOI: 10.1186/1471-2148-7-246] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Accepted: 12/21/2007] [Indexed: 11/10/2022] Open
Abstract
Background The major lineages of eusocial insects, the ants, termites, stingless bees, honeybees and vespid wasps, all have ancient origins (≥ 65 mya) with no reversions to solitary behaviour. This has prompted the notion of a 'point of no return' whereby the evolutionary elaboration and integration of behavioural, genetic and morphological traits over a very long period of time leads to a situation where reversion to solitary living is no longer an evolutionary option. Results We show that in another group of social insects, the allodapine bees, there was a single origin of sociality > 40 mya. We also provide data on the biology of a key allodapine species, Halterapis nigrinervis, showing that it is truly social. H. nigrinervis was thought to be the only allodapine that was not social, and our findings therefore indicate that there have been no losses of sociality among extant allodapine clades. Allodapine colony sizes rarely exceed 10 females per nest and all females in virtually all species are capable of nesting and reproducing independently, so these bees clearly do not fit the 'point of no return' concept. Conclusion We argue that allodapine sociality has been maintained by ecological constraints and the benefits of alloparental care, as opposed to behavioural, genetic or morphological constraints to independent living. Allodapine brood are highly vulnerable to predation because they are progressively reared in an open nest (not in sealed brood cells), which provides potentially large benefits for alloparental care and incentives for reproductives to tolerate potential alloparents. We argue that similar vulnerabilities may also help explain the lack of reversions to solitary living in other taxa with ancient social origins.
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Affiliation(s)
- Luke B Chenoweth
- Biological Sciences, Flinders University GPO BOX 2100, Adelaide, SA 5001, Australia.
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Wilson R, Heinrichs J, Hentschel J, Gradstein SR, Schneider H. Steady diversification of derived liverworts under Tertiary climatic fluctuations. Biol Lett 2007; 3:566-9. [PMID: 17686755 PMCID: PMC2391190 DOI: 10.1098/rsbl.2007.0287] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Tropical forests contain the majority of extant plant diversity and their role as a cradle and/or museum of biodiversity is an important issue in our attempts to assess the long-term consequences of global climate change for terrestrial biomes. Highly diverse groups of liverworts are an often ignored but extremely common element in rainforests, and thus their evolution may shed light on the ecological robustness of rainforest biomes to climate fluctuations. We record a remarkable constant accumulation of diversity through time for the most species-rich family of liverworts, Lejeuneaceae, inferred by divergence time estimates. The observed pattern supports the recently developed concept of a dual role of the tropics as both a museum and a cradle of biodiversity.
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Affiliation(s)
- Rosemary Wilson
- Albrecht-von-Haller Institute of Plant Sciences, Georg-August University Göttingen, 37073 Göttingen, Germany.
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