Evolution repeats itself in replicate long-term studies in the wild.

The extent to which evolution is repeatable remains debated. Here, we study changes over time in the frequency of cryptic color-pattern morphs in 10 replicate long-term field studies of a stick insect, each spanning at least a decade (across 30 years of total data). We find predictable "up-and-down" fluctuations in stripe frequency in all populations, representing repeatable evolutionary dynamics based on standing genetic variation. A field experiment demonstrates that these fluctuations involve negative frequency-dependent natural selection (NFDS). These fluctuations rely on demographic and selective variability that pushes populations away from equilibrium, such that they can reliably move back toward it via NFDS. Last, we show that the origin of new cryptic forms is associated with multiple structural genomic variants such that which mutations arise affects evolution at larger temporal scales. Thus, evolution from existing variation is predictable and repeatable, but mutation adds complexity even for traits evolving deterministically under natural selection.

Genetic variation within a stick-insect species associated with community-level traits.

Phenotypic variation within species can affect the ecological dynamics of populations and communities. Characterizing the genetic variation underlying such effects can help parse the roles of genetic evolution and plasticity in "eco-evolutionary dynamics" and inform how genetic variation may shape patterns of evolution. Here, we employ genome-wide association (GWA) methods in Timema cristinae stick insects and their co-occurring arthropod communities to identify genetic variation associated with community-level traits. Previous studies have shown that maladaptation (i.e., imperfect crypsis) of T. cristinae can reduce the abundance and species richness of other arthropods due to an increase in bird predation. Whether genetic variation that is independent of crypsis has similar effects is unknown and was tested here using genome-wide genotyping-by-sequencing data of stick insects, arthropod community information, and GWA mapping with Bayesian sparse linear mixed models. We find associations between genetic variation in stick insects and arthropod community traits. However, these associations disappear when host-plant traits are accounted for. We thus use path analysis to disentangle interrelationships among stick-insect genetic variation, host-plant traits, and community traits. This revealed that host-plant size has large effects on arthropod communities, while genetic variation in stick insects has a smaller, but still significant effect. Our findings demonstrate that (1) genetic variation in a species can be associated with community-level traits but that (2) interrelationships among multiple factors may need to be analyzed to disentangle whether such associations represent causal relationships. This work helps to build a framework for genomic studies of eco-evolutionary dynamics.

A stabilizing eco-evolutionary feedback loop in the wild.

There is increasing evidence that evolutionary and ecological processes can operate on the same timescale1,2 (i.e., contemporary time). As such, evolution can be sufficiently rapid to affect ecological processes such as predation or competition. Thus, evolution can influence population, community, and ecosystem-level dynamics. Indeed, studies have now shown that evolutionary dynamics can alter community structure3,4,5,6 and ecosystem function.7,8,9,10 In turn, shifts in ecological dynamics driven by evolution might feed back to affect the evolutionary trajectory of individual species.11 This feedback loop, where evolutionary and ecological changes reciprocally affect one another, is a central tenet of eco-evolutionary dynamics.1,12 However, most work on such dynamics in natural populations has focused on one-way causal associations between ecology and evolution.13 Hence, direct empirical evidence for eco-evolutionary feedback is rare and limited to laboratory or mesocosm experiments.13,14,15,16 Here, we show in the wild that eco-evolutionary dynamics in a plant-feeding arthropod community involve a negative feedback loop. Specifically, adaptation in cryptic coloration in a stick-insect species mediates bird predation, with local maladaptation increasing predation. In turn, the abundance of arthropods is reduced by predation. Here, we experimentally manipulate arthropod abundance to show that these changes at the community level feed back to affect the stick-insect evolution. Specifically, low-arthropod abundance increases the strength of selection on crypsis, increasing local adaptation of stick insects in a negative feedback loop. Our results suggest that eco-evolutionary feedbacks are able to stabilize complex systems by preventing consistent directional change and therefore increasing resilience.

A synopsis of the tribe Lachnophorini, with a new genus of Neotropical distribution and a revision of the Neotropical genus Asklepia Liebke, 1938 (Insecta, Coleoptera, Carabidae).

This synopsis provides an identification key to the genera of Tribe Lachnophorini of the Western and Eastern Hemispheres including five genera previously misplaced in carabid classifications. The genus Asklepia Liebke, 1938 is revised with 23 new species added and four species reassigned from Eucaerus LeConte, 1853 to Asklepia Liebke, 1938. In addition, a new genus is added herein to the Tribe: Peruphorticus gen. n. with its type species P. gulliveri sp. n. from Perú. Five taxa previously assigned to other tribes have adult attributes that make them candidates for classification in the Lachnophorini: Homethes Newman, Aeolodermus Andrewes, Stenocheila Laporte de Castelnau, Diplacanthogaster Liebke, and Selina Motschulsky are now considered to belong to the Lachnophorini as genera incertae sedis. Three higher level groups are proposed to contain the 18 recognized genera: the Lachnophorina, Eucaerina, and incertae sedis. Twenty-three new species of the genus Asklepia are described and four new combinations are presented. They are listed with their type localities as follows: ( geminata species group) Asklepia geminata (Bates, 1871), comb. n, Santarém, Rio Tapajós, Brazil; ( hilaris species group) Asklepia campbellorum Zamorano & Erwin, sp. n., 20 km SW Manaus, Brazil, Asklepia demiti Erwin & Zamorano, sp. n., circa Rio Demiti, Brazil, Asklepia duofos Zamorano & Erwin, sp. n., 20 km SW Manaus, Brazil, Asklepia hilaris (Bates, 1871), comb. n, São Paulo de Olivença, Brazil, Asklepia grammechrysea Zamorano & Erwin, sp. n., circa Pithecia, Cocha Shinguito, Perú, Asklepia lebioides (Bates, 1871), comb. n, Santarém, Rio Tapajós, Brazil, Asklepia laetitia Zamorano & Erwin, sp. n., Leticia, Colombia, Asklepia matomena Zamorano & Erwin, sp.n., 20 km SW Manaus, Brazil; ( pulchripennis species group) Asklepia adisi Erwin & Zamorano, sp. n., Ilha de Marchantaria, Lago Camaleão, Brazil, Asklepia asuncionensis Erwin & Zamorano, sp. n., Asunción, Río Paraguay, Paraguay, Asklepia biolat Erwin & Zamorano, sp. n., BIOLAT Biological Station, Pakitza, Perú, Asklepia bracheia Zamorano & Erwin, sp. n., circa Explornapo Camp, Río Napo, Cocha Shimagai, Perú, Asklepia cuiabaensis Erwin & Zamorano, sp. n., Cuiabá, Brazil, Asklepia ecuadoriana Erwin & Zamorano, sp. n., Limoncocha, Ecuador, Asklepia kathleenae Erwin & Zamorano, sp. n., Belém, Brazil, Asklepia macrops Erwin & Zamorano, sp. n., Concordia, Río Uruguay, Argentina, Asklepia marchantaria Erwin & Zamorano, sp. n., Ilha de Marchantaria, Lago Camaleão, Brazil, Asklepia marituba Zamorano & Erwin, sp. n., Marituba, Ananindeua, Brazil, Asklepia paraguayensis Zamorano & Erwin, sp. n., San Lorenzo, Rio Paraguay, Paraguay, Asklepia pakitza Erwin & Zamorano, sp. n., BIOLAT Biological Station, Pakitza, Perú, Asklepia pulchripennis (Bates, 1871), comb. n, Santarém, Rio Tapajós, Brazil, Asklepia samiriaensis Zamorano & Erwin, sp. n., Boca del Río Samiria, Perú, Asklepia stalametlitos Zamorano & Erwin, sp. n., Guayamer, Río Mamoré, Bolivia, Asklepia strandi Liebke, 1938, Guyana, Asklepia surinamensis Zamorano & Erwin, sp. n., l'Hermitage, Surinam River, Surinam, Asklepia vigilante Erwin & Zamorano, sp. n., Boca del Río Samiria, Perú. Images of adults of all 18 genera are provided.

ResumenLa presente sinopsis provee una clave dicotómica para todos los géneros del hemisferio oriental y occidental incluyendo cinco géneros anteriormente mal clasificados dentro de Carabidae. El género Asklepia Liebke, 1938 es revisado; 23 especies nuevas para la ciencia son incluídas, además de cuatro especies de Eucaerus LeConte, 1853, que son reasignadas dentro del género Asklepia Liebke, 1938. Adicionalmente, un nuevo género es asignado dentro de la tribu: Peruphorticusgen. n. y la especie tipo P. gulliverisp. n. de Perú. Cinco taxones anteriormente asignados a otras tribus presentan atributos que los hacen buenos canditados para ser clasificados como Lachnophorini: Homethes Newman, Aeolodermus Andrewes, Stenocheila Laporte de Castelnau, Diplacanthogaster Liebke y Selina Motschulsky, son actualmente considerados como pertenecientes del complejo Lachnophorini como géneros incertae sedis. Se propone que los 18 géneros se distribuyen en tres taxones superiores: Lachnophorina, Eucaerina e incertae sedis.Veinte y tres especies nuevas del género Asklepia son descritas y cuatro nuevas combinaciones son presentadas. Todas las especies y sus localidades tipo son enlistadas de la manera siguiente: (grupo de especies geminata)Asklepia geminata (Bates, 1871), comb. n, Santarém, Rio Tapajós, Brazil; (grupo de especies hilaris)Asklepia campbellorum Zamorano & Erwin, sp. n., 20 km SW Manaus, Brazil, Asklepia demiti Erwin & Zamorano, sp. n., circa Rio Demiti, Brazil, Asklepia duofos Zamorano & Erwin, sp. n., 20 km SW Manaus, Brazil, Asklepia hilaris (Bates, 1871), comb. n, São Paulo de Olivença, Brazil, Asklepia grammechrysea Zamorano & Erwin, sp. n., circa Pithecia, Cocha Shinguito, Perú, Asklepia lebioides (Bates, 1871), comb. n, Santarém, Rio Tapajós, Brazil, Asklepia laetitia Zamorano & Erwin, sp. n., Leticia, Colombia, Asklepia matomena Zamorano & Erwin, sp. nov., 20 km SW Manaus, Brazil; (grupo de especies pulchripennis)Asklepia adisi Erwin & Zamorano, sp. n., Ilha de Marchantaria, Lago Camaleão, Brazil, Asklepia asuncionensis Erwin & Zamorano, sp. n., Asunción, Río Paraguay, Paraguay, Asklepia biolat Erwin & Zamorano, sp. n., BIOLAT Biological Station, Pakitza, Perú, Asklepia bracheia Zamorano & Erwin, sp. n., circa Explornapo Camp, Río Napo, Cocha Shimagai, Perú, Asklepia cuiabaensis Erwin & Zamorano, sp. n., Cuiabá, Brazil, Asklepia ecuadoriana Erwin & Zamorano, sp. n., Limoncocha, Ecuador, Asklepia kathleenae Erwin & Zamorano, sp. n., Belém, Brazil, Asklepia macrops Erwin & Zamorano, sp. n., Concordia, Río Uruguay, Argentina, Asklepia marchantaria Erwin & Zamorano, sp. n., Ilha de Marchantaria, Lago Camaleão, Brazil, Asklepia marituba Zamorano & Erwin, sp. n., Marituba, Ananindeua, Brazil, Asklepia paraguayensis Zamorano & Erwin, sp. n., San Lorenzo, Río Paraguay, Paraguay, Asklepia pakitza Erwin & Zamorano, sp. n., BIOLAT Biological Station, Pakitza, Perú, Asklepia pulchripennis (Bates, 1871), comb. n, Santarém, Rio Tapajós, Brazil, Asklepia samiriaensis Zamorano & Erwin, sp. n., Boca del Río Samiria, Perú, Asklepia stalametlitos Zamorano & Erwin, sp. n., Guayamer, Río Mamoré, Bolivia, Asklepia strandi Liebke, 1938, Guyana, Asklepia surinamensissp. n., l'Hermitage, Surinam River, Surinam, Asklepia vigilante Erwin & Zamorano, sp. n., Boca del Río Samiria, Perú. Imágenes de los adultos de los 18 géneros son proporcionadas.

Crystal structure and statistical coupling analysis of highly glycosylated peroxidase from royal palm tree (Roystonea regia).

Royal palm tree peroxidase (RPTP) is a very stable enzyme in regards to acidity, temperature, H(2)O(2), and organic solvents. Thus, RPTP is a promising candidate for developing H(2)O(2)-sensitive biosensors for diverse applications in industry and analytical chemistry. RPTP belongs to the family of class III secretory plant peroxidases, which include horseradish peroxidase isozyme C, soybean and peanut peroxidases. Here we report the X-ray structure of native RPTP isolated from royal palm tree (Roystonea regia) refined to a resolution of 1.85A. RPTP has the same overall folding pattern of the plant peroxidase superfamily, and it contains one heme group and two calcium-binding sites in similar locations. The three-dimensional structure of RPTP was solved for a hydroperoxide complex state, and it revealed a bound 2-(N-morpholino) ethanesulfonic acid molecule (MES) positioned at a putative substrate-binding secondary site. Nine N-glycosylation sites are clearly defined in the RPTP electron-density maps, revealing for the first time conformations of the glycan chains of this highly glycosylated enzyme. Furthermore, statistical coupling analysis (SCA) of the plant peroxidase superfamily was performed. This sequence-based method identified a set of evolutionarily conserved sites that mapped to regions surrounding the heme prosthetic group. The SCA matrix also predicted a set of energetically coupled residues that are involved in the maintenance of the structural folding of plant peroxidases. The combination of crystallographic data and SCA analysis provides information about the key structural elements that could contribute to explaining the unique stability of RPTP.

Thermal stability of peroxidase from Chamaerops excelsa palm tree at pH 3.

The structural stability of a peroxidase, a dimeric protein from palm tree Chamaerops excelsa leaves (CEP), has been characterized by high-sensitivity differential scanning calorimetry, circular dichroism and steady-state tryptophan fluorescence at pH 3. The thermally induced denaturation of CEP at this pH value is irreversible and strongly dependent upon the scan rate, suggesting that this process is under kinetic control. Moreover, thermally induced transitions at this pH value are dependent on the protein concentration, leading to the conclusion that in solution CEP behaves as dimer, which undergoes thermal denaturation coupled with dissociation. Analysis of the kinetic parameters of CEP denaturation at pH 3 was accomplished on the basis of the simple kinetic scheme N-->kD, where k is a first-order kinetic constant that changes with temperature, as given by the Arrhenius equation; N is the native state, and D is the denatured state, and thermodynamic information was obtained by extrapolation of the kinetic transition parameters to an infinite heating rate.

Thermodynamic characterization of the palm tree Roystonea regia peroxidase stability.

The structural stability of a peroxidase, a dimeric protein from royal palm tree (Roystonea regia) leaves, has been characterized by high-sensitivity differential scanning calorimetry, circular dichroism, steady-state tryptophan fluorescence and analytical ultracentifugation under different solvent conditions. It is shown that the thermal and chemical (using guanidine hydrochloride (Gdn-HCl)) folding/unfolding of royal palm tree peroxidase (RPTP) at pH 7 is a reversible process involving a highly cooperative transition between the folded dimer and unfolded monomers, with a free stabilization energy of about 23 kcal per mol of monomer at 25 degrees C. The structural stability of RPTP is pH-dependent. At pH 3, where ion pairs have disappeared due to protonation, the thermally induced denaturation of RPTP is irreversible and strongly dependent upon the scan rate, suggesting that this process is under kinetic control. Moreover, thermally induced transitions at this pH value are dependent on the protein concentration, allowing it to be concluded that in solution RPTP behaves as dimer, which undergoes thermal denaturation coupled with dissociation. Analysis of the kinetic parameters of RPTP denaturation at pH 3 was accomplished on the basis of the simple kinetic scheme N-->kD, where k is a first-order kinetic constant that changes with temperature, as given by the Arrhenius equation; N is the native state, and D is the denatured state, and thermodynamic information was obtained by extrapolation of the kinetic transition parameters to an infinite heating rate. Obtained in this way, the value of RPTP stability at 25 degrees C is ca. 8 kcal per mole of monomer lower than at pH 7. In all probability, this quantity reflects the contribution of ion pair interactions to the structural stability of RPTP. From a comparison of the stability of RPTP with other plant peroxidases it is proposed that one of the main factors responsible for the unusually high stability of RPTP which enhances its potential use for biotechnological purposes, is its dimerization.

Purification, crystallization and preliminary X-ray diffraction analysis of royal palm tree (Roystonea regia) peroxidase.

Royal palm tree peroxidase (RPTP), which was isolated from Roystonea regia leaves, has an unusually high stability that makes it a promising candidate for diverse applications in industry and analytical chemistry [Caramyshev et al. (2005), Biomacromolecules, 6, 1360-1366]. Here, the purification and crystallization of this plant peroxidase and its X-ray diffraction data collection are described. RPTP crystals were obtained by the hanging-drop vapour-diffusion method and diffraction data were collected to a resolution of 2.8 A. The crystals belong to the trigonal space group P3(1)21, with unit-cell parameters a = b = 116.83, c = 92.24 A, and contain one protein molecule per asymmetric unit. The V(M) value and solvent content are 4.07 A3 Da(-1) and 69.8%, respectively.