Intraspecific Size Variation Research Articles

First description of an ostrich from the late Miocene of Kerassia (Euboea, Greece): remarks on its cervical anatomy

ABSTRACT The present study describes an almost complete cervical region of the fossil ostrich Struthio karatheodoris from the Turolian locality of Kerassia (Euboea, Greece). The material comes from two distinct fossiliferous horizons and consists of twelve cervical vertebrae, ten of which belong to the same individual. These specimens are the first remains of a large flightless bird from Kerassia and represent some of the very few findings of the genus Struthio in the sub-Paratethyan (Balkan-Iranian) bioprovince from the late Miocene. The morphology of the cervical vertebrae implies that the neck of S. karatheodoris had similar biomechanical properties to that of extant ostriches, pointing to similar ecological adaptations, relating to food procurement. However, it probably had a more flexible and stronger neck, which might indicate a somewhat different ecology. Furthermore, considerable intraspecific size and morphological variation of the cervical vertebrae of S. karatheodoris is observed. This signifies that S. karatheodoris was not necessarily larger than S. camelus as previously suspected, but their size ranges in fact overlap significantly.

Inter- and intraspecific variation in grass phytolith shape and size: a geometric morphometrics perspective.

The relative contributions of inter- and intraspecific variation to phytolith shape and size have only been investigated in a limited number of studies. However, a detailed understanding of phytolith variation patterns among populations or even within a single plant specimen is of key importance for the correct taxonomic identification of grass taxa in fossil samples and for the reconstruction of vegetation and environmental conditions in the past. In this study, we used geometric morphometric analysis for the quantification of different sources of phytolith shape and size variation. We used landmark-based geometric morphometric methods for the analysis of phytolith shapes in two extant grass species (Brachypodium pinnatum and B. sylvaticum). For each species, 1200 phytoliths were analysed from 12 leaves originating from six plants growing in three populations. Phytolith shape and size data were subjected to multivariate Procrustes analysis of variance (ANOVA), multivariate regression, principal component analysis and linear discriminant analysis. Interspecific variation largely outweighed intraspecific variation with respect to phytolith shape. Individual phytolith shapes were classified with 83 % accuracy into their respective species. Conversely, variation in phytolith shapes within species but among populations, possibly related to environmental heterogeneity, was comparatively low. Our results imply that phytolith shape relatively closely corresponds to the taxonomic identity of closely related grass species. Moreover, our methodological approach, applied here in phytolith analysis for the first time, enabled the quantification and separation of variation that is not related to species discrimination. Our findings strengthen the role of grass phytoliths in the reconstruction of past vegetation dynamics.

Ampliconic Genes on the Great Ape Y Chromosomes: Rapid Evolution of Copy Number but Conservation of Expression Levels.

Multicopy ampliconic gene families on the Y chromosome play an important role in spermatogenesis. Thus, studying their genetic variation in endangered great ape species is critical. We estimated the sizes (copy number) of nine Y ampliconic gene families in population samples of chimpanzee, bonobo, and orangutan with droplet digital polymerase chain reaction, combined these estimates with published data for human and gorilla, and produced genome-wide testis gene expression data for great apes. Analyzing this comprehensive data set within an evolutionary framework, we, first, found high inter- and intraspecific variation in gene family size, with larger families exhibiting higher variation as compared with smaller families, a pattern consistent with random genetic drift. Second, for four gene families, we observed significant interspecific size differences, sometimes even between sister species—chimpanzee and bonobo. Third, despite substantial variation in copy number, Y ampliconic gene families’ expression levels did not differ significantly among species, suggesting dosage regulation. Fourth, for three gene families, size was positively correlated with gene expression levels across species, suggesting that, given sufficient evolutionary time, copy number influences gene expression. Our results indicate high variability in size but conservation in gene expression levels in Y ampliconic gene families, significantly advancing our understanding of Y-chromosome evolution in great apes.

Intraspecific trait variation across elevation predicts a widespread tree species' climate niche and range limits.

Global change is widely altering environmental conditions which makes accurately predicting species range limits across natural landscapes critical for conservation and management decisions. If climate pressures along elevation gradients influence the distribution of phenotypic and genetic variation of plant functional traits, then such trait variation may be informative of the selective mechanisms and adaptations that help define climatic niche limits. Using extensive field surveys along 16 elevation transects and a large common garden experiment, we tested whether functional trait variation could predict the climatic niche of a widespread tree species (Populus angustifolia) with a double quantile regression approach. We show that intraspecific variation in plant size, growth, and leaf morphology corresponds with the species' total climate range and certain climatic limits related to temperature and moisture extremes. Moreover, we find evidence of genetic clines and phenotypic plasticity at environmental boundaries, which we use to create geographic predictions of trait variation and maximum values due to climatic constraints across the western US. Overall, our findings show the utility of double quantile regressions for connecting species distributions and climate gradients through trait‐based mechanisms. We highlight how new approaches like ours that incorporate genetic variation in functional traits and their response to climate gradients will lead to a better understanding of plant distributions as well as identifying populations anticipated to be maladapted to future environments.

Intraspecific diversity in prey body size influences survivorship by conferring resistance to predation

AbstractIntraspecific diversity can have as strong an effect on communities and ecosystems as more well‐studied effects of species diversity. Intraspecific variation in prey body size may have particularly strong effects on populations by influencing the outcome of predator–prey interactions, but this has received little attention. We tested the hypotheses that (1) body size of the Sydney Rock Oyster,Sacosstrea glomerata, influences predation risk; (2) increasing intraspecific variation in body size of the oyster will enhance total survivorship; (3) oyster size phenotypes will differ in the magnitude of survivorship benefits they incur from association with other phenotypes; and (4) size‐specific survivorship benefits of associating with other body sizes will vary with predator access. In a fully factorial field experiment, we manipulated the diversity ofS. glomerataoyster body sizes (1–3 size classes per treatment) and predator access to prey (small vs. large mesh cages). Oyster total and individual phenotype survivorship was documented over an 8‐week period. Overall, the relationship between diversity inS. glomeratabody size and survivorship was positive and was related to changes in density of individual body sizes when grown in mixtures. In fact, no phenotype had lower percent survivorship in mixtures than in monoculture. Nevertheless, individual phenotypes displayed differing responses to predator access treatments and phenotype mixing that reflected differences in the types of predators (e.g., shell drilling or removing) to which they were most susceptible. In general, the greatest survivorship benefits of phenotype mixing were seen in treatments where the most disparate (i.e., small, large) size classes were mixed. Our study adds to growing evidence of the importance of intraspecific diversity in mediating key population processes such as predation. Importantly, different oyster phenotypes benefit from increasing phenotypic diversity depending on the predators that can access the oysters, suggesting that flexible complementarity among oyster phenotypes may be a useful tool for increasing the resistance and resilience of oysters in a range of environments which vary in their predator composition. These results will help to inform strategies for enhancing survivorship of species transplants in restoration projects.

Phenotypic matching in ovipositor size in the parasitoid Galeopsomyia sp. (Hymenoptera, Eulophidae) attacking different gall inducers

ABSTRACT Parasitoid ovipositor size importantly affects host choice; those attacking exposed hosts usually have shorter ovipositors compared to those needing drilling deeper through substrates such as plant tissue and gall tissue. Most studies treat this theme at the interspecific level, and the aim of this work was to test for intraspecific variation and phenotypic matching in ovipositor size for Galeopsomyia sp. attacking galls. Galls were sampled from Guapira opposita(Nyctaginaceae), a host plant to five species of Bruggmannia gallers (Diptera, Cecidomyiidae) in southern Brazil: Bruggmannia elongata, B. robusta, B. acaudata, and two undescribed species of Bruggmannia (sp. 1 and sp. 2). On forest transects, all galls from the 30 first galled plants found were sampled and kept in sealed plastic bags until parasitoid emergence. A total of 15 samples were done along two years. We measured galler last instar larvae length and gall thickness for each galling species, and ovipositor length for all Galeopsomyia sp. individuals emerging from the galls. There were no differences in larval length among galler species. However, Bruggmannia sp. 1 and sp. 2 galls were significantly thicker than those of B. acaudata, and the latter thicker than both B. elongata and B. robusta galls. Wasp ovipositor size differed significantly between those coming from Bruggmannia sp. 1 and sp. 2 galls relative to all others. Host extended phenotype size is thus fundamental to determine parasitoid size, but in this case host (larval) size does not change among species, although gall thickness was different. Thicker galls were attacked by larger parasitoids with longer ovipositors, denoting phenotypic matching. Thicker galls appear to be selecting larger parasitoid individuals, which in the long run can lead to important evolutionary change as well.

Intraspecific variation in body size of bumblebee workers influences anti-predator behaviour.

Flower-dwelling predators make flowers dangerous foraging sites for pollinators, potentially affecting their anti-predator behaviour. Moreover, predation vulnerability often varies among pollinators' body sizes with interspecific comparisons showing that smaller species are more vulnerable than larger ones. However, how intraspecific body size variation influences pollinator behaviour under predation risk is still unknown, especially under natural conditions. We hypothesized that bumblebee workers of different sizes will exhibit different foraging strategies under predation risk. We predict that (a) small workers should more often exhibit anti-predator behaviours than larger workers. We also hypothesized that the anti-predator behaviour should be influenced by predator size and reward availability; therefore, we expect (b) higher avoidance behaviour towards larger predator sizes and (c) more and longer visits to inflorescences with high nectar availability. Finally, we expect that (d) nectar availability should overcome the anti-predator behaviour in less vulnerable, large, workers. We recorded flower visitation, time spent and rejection behaviours of different sizes of Bombus terrestris (Apidae) workers (large, medium and small) to inflorescences of Alstroemeria aurea (Alstroemeriaceae) with different treatments of artificial spiders (small and large) and nectar availability (with, without). Anti-predator and foraging behaviour of bumblebees was affected by the size of the worker, the presence of artificial spiders and nectar availability. Large and medium size bumblebees strongly reduced flower visitation and time spent in the presence of artificial spiders, consistently avoiding flowers with spiders, regardless of spider size or nectar availability. Instead, small bumblebees seldom modified their behaviour when facing artificial spiders, only increasing their avoidance or decreasing their foraging time in nectarless flowers hosting large artificial spiders. This pattern of larger workers being more sensitive to predation risk than smaller ones at the intraspecific level in B.terrestris is contrary to the expected and acknowledged trend based on previous interspecific comparisons, but partially consistent with predictions of models of optimal foraging theory. Intraspecific behavioural variability was uncovered only when nectar was available, whereas artificial predator size rarely modified bumblebee anti-predator and foraging behaviour. Therefore, our findings suggest that the trade-off between maximizing resource intake and minimizing predation risk strongly varies across bumblebee worker body sizes.

Spatiotemporal variation in leaf size and shape in response to climate

Abstract Aims Morphological variation of leaves is a key indicator of plant response to climatic change. Leaf size and shape are associated with carbon, water and energy exchange of plants with their environment. However, whether and how leaf size and shape responded to climate change over the past decades remains poorly studied. Moreover, many studies have only explored inter- but not intraspecific variation in leaf size and shape across space and time. Methods We collected >6000 herbarium specimens spanning 98 years (1910–2008) in China for seven representative dicot species and measured their leaf length and width. We explored geographical patterns and temporal trends in leaf size (i.e. leaf length, leaf width and length × width product) and shape (i.e. length/width ratio), and investigated the effects of changes in precipitation and temperature over time and space on the variation in leaf size and shape. Important Findings After accounting for the effects of sampling time, leaf size decreased with latitude for all species combined, but the relationship varied among species. Leaf size and shape were positively correlated with temperature and precipitation across space. After accounting for the effects of sampling locations, leaf size of all species combined increased with time. Leaf size changes over time were mostly positively correlated with precipitation, whereas leaf shape changes were mostly correlated with temperature. Overall, our results indicate significant spatial and temporal intraspecific variation in leaf size and shape in response to climate. Our study also demonstrates that herbarium specimens collected over a considerable period of time provide a good resource to study the impacts of climate change on plant morphological traits.

Three-dimensional analysis of inter-and intraspecific variation in ontogenetic growth trajectories of planktonic foraminifera

Abstract Planktonic foraminifera grow by adding chambers onto their tests, modifying their surface area, volume, porosity, and ornamentation with each addition. This process results in a wide variety of adult morphologies and preserves a record of the early morphology. With high-resolution three-dimensional imaging techniques, precise measurements can be made on previously inaccessible parameters like surface area and volume of the test interior. Here, we used three-dimensional images (microCT scans) of extant planktonic foraminifera from plankton tows and sediment traps to measure and compare the variation in chamber and whole test volume within and between seven morphospecies. By incorporating data from Caromel et al., (2015), we were able to explore the extent of interspecific variation in growth (i.e., total volume) with each chamber addition from a total of 12 extant species. All species measured approximately adhered to log-linear growth trajectories through the majority of their ontogeny. Species exhibited characteristic deviations from the log-linear growth trajectory and were grouped into three categories on the basis thereon. The volume of the first chamber—the proloculus—varied by more than two orders of magnitude. However, subtle differences in relative growth rates could make up for the initial variation proloculus size, such that the correlation between proloculus size and biovolume decreased through ontogeny. Intraspecific variation in proloculus size, cavity volume at the final five chamber stages, and terminal calcite volume was pronounced in the seven morphospecies investigated and attributed environmental and ontogenetic differences among individuals. Finally, we generated linear models for estimating cell volume and calcium carbonate test volume from linear measurements (major and minor axis) that are more accurate than the spherical equivalents used previously.

On the systematics and ecology of two new species ofProvanna(Gastropoda: Provannidae) from deep-sea hydrothermal vents in the Caribbean Sea and Southern Ocean

ABSTRACTThe recent discovery and exploration of deep-sea hydrothermal vent fields in the Mid-Cayman Spreading Centre, Caribbean Sea (Beebe Vent Field, 4956–4972 m depth) and the East Scotia Ridge, Southern Ocean (E2 and E9 vent fields, 2394–2641 m depth) have yielded extensive collections of two new provannid species, Provanna beebei n. sp. and P. cooki n. sp. Morphological and molecular taxonomy (530 bp of the mitochondrial cytochrome c oxidase subunit I gene) confirm P. beebei n. sp. and P. cooki n. sp. as distinct species; these species are formally described, and details are provided of their distribution, habitat and species associations. Bayesian and maximum likelihood analyses support the placement of P. beebei n. sp. and P. cooki n. sp within the genus Provanna and show that these two new deep-sea species form a well-supported clade with the abyssal West Pacific P. cingulata. Provanna beebei n. sp. and P. cooki n. sp. represent the first records of Provanna from hydrothermal vents in the Caribbean Sea and Southern Ocean, respectively, and extend the known geographic range of the genus. For the first time, intraspecific phenotypic variation in size and sculpture has been reported for Provanna. At the East Scotia Ridge, shell-size frequency distributions and median shell size of P. cooki n. sp. varied significantly between the E2 and E9 vent fields, as well as between diffuse flow and high-temperature venting habitats within each field. The variation in shell sculpture in relation to habitat was also observed in P. cooki n. sp.

Comparison of otolith morphology of invasive big-scale sand smelt (Atherina boyeri) from natural and artificial lakes in Turkey.

In this study, otolith morphology and otolith contour from big-scale sand smelt, Atherina boyeri were analyzed in Lake Egirdir and Lake Iznik (natural lakes), and Hirfanli Dam Lake (artificial lake). The otolith contour and sixteen otolith morphological characters such as width, depth, shape, sulcus acusticus shape, ostium, cauda, rostrum size-shape, and thickness, antirostrum size-shape, and thickness, anterior and posterior regions, mesial and lateral surfaces were successfully investigated for three total length groups of A. boyeri inhabiting the lakes. Intraspecific variation in rostrum shape, rostrum size, rostrum thickness, antirostrum, anterior region, mesial and lateral surfaces were observed for the three total length groups of three A. boyeri populations. In the three different lakes, saccular otoliths surface morphology of A. boyeri were detected such as flatten surface for Lake Egirdir, rough surface for Lake Iznik, and relatively smooth surface for Hirfanli Dam Lake using the Scanning Electron Microscope. The otolith contours were noticeable difference in the three total length groups of A. boyeri from the different lakes. Intraspecific variability of the otolith characters and morphology consist of the otolith surface morphology and otolith contour were presented and compared for the three total length groups of the A. boyeri from the different lakes.

Intraspecific Energetic Trade-Offs and Costs of Encephalization Vary from Interspecific Relationships in Three Species of Mormyrid Electric Fishes

The evolution of increased encephalization comes with an energetic cost. Across species, this cost may be paid for by an increase in metabolic rate or by energetic trade-offs between the brain and other energy-expensive tissues. However, it remains unclear whether these solutions to deal with the energetic requirements of an enlarged brain are related to direct physiological constraints or other evolved co-adaptations. We studied the highly encephalized mormyrid fishes, which have extensive species diversity in relative brain size. We previously found a correlation between resting metabolic rate and relative brain size across species; however, it is unknown how this interspecific relationship evolved. To address this issue, we measured intraspecific variation in relative brain size, the sizes of other organs, metabolic rate, and hypoxia tolerance to determine if intraspecific relationships between brain size and organismal energetics are similar to interspecific relationships. We found that 3 species of mormyrids with varying degrees of encephalization had no intraspecific relationships between relative brain size and relative metabolic rate or relative sizes of other organs, and only 1 species had a relationship between relative brain size and hypoxia tolerance. These species-specific differences suggest that the interspecific relationship between metabolic rate and relative brain size is not the result of direct physiological constraints or strong stabilizing selection, but is instead due to other species level co-adaptations. We conclude that variation within species must be considered when determining the energetic costs and trade-offs underlying the evolution of extreme encephalization.

Field estimates of fitness costs of the pace‐of‐life in an endangered damselfly

Theory predicts that within-population differences in the pace-of-life can lead to cohort splitting and produce marked intraspecific variation in body size. Although many studies showed that body size is positively correlated with fitness, many argue that selection for the larger body is counterbalanced by opposing physiological and ecological selective mechanisms that favour smaller body. When a population split into cohorts with different paces of life (slow or fast cohort), one would expect to detect the fitness-size relationship among and within cohorts, that is, (a) slower-developing cohort has larger body size and higher fitness than faster-developing cohort, and (b) larger individuals within each cohort show higher fitness than smaller individuals. Here, we test these hypotheses in capture-mark-recapture field surveys that assess body size, lifespan, survival and lifetime mating success in two consecutive generations of a partially bivoltine aquatic insect, Coenagrion mercuriale, where the spring cohort is slower-developing than the autumn cohort. As expected, body size was larger in the slow-developing cohort, which is consistent with the temperature-size rule and also with the duration of development. Body size seasonal variation was greater in slow-developing cohort most likely because of the higher variation in age at maturity. Concordant with theory, survival probability, lifespan and lifetime mating success were higher in the slow-developing cohort. Moreover, individual body size was positively correlated with survival and mating success in both cohorts. Our study confirms the fitness costs of fast pace-of-life and the benefits of larger body size to adult fitness.

Brontostoma lilloi Carpintero, 1980, a junior synonym of B. rubrovenosum (Stål, 1860) (Hemiptera: Heteroptera: Reduviidae)

There are 22 genera and more than 100 described species of Ectrichodiinae in the New World (Gil-Santana et al. 2015). Intraspecific variation in coloration and body size have been recorded in several species of the subfamily. These characteristics can occur in the same population or can suggest geographic variation of the same species (Wygodzinsky 1951, Dougherty 1995, Gil-Santana Baena 2009, Gil-Santana et al. 2013). Sexual dimorphism is also common: females are almost always more or less larger than males, frequently have thicker fore femora and smaller eyes and ocelli (Dougherty 1995).

Cayaoa bruneti (Aves: Anseriformes) from the Early Miocene of Patagonia, Argentina: New Materials and Revised Diagnosis

We restudy the holotype specimen and all the alleged fossil material assigned to Cayaoa bruneti Tonni from the Early Miocene marine deposits of the Gaiman Formation, Patagonia, Argentina. Cayaoa bruneti is phylogenetically placed close to the Erismaturinae (= ”Oxyurinae”) that contains the diving birds. It was considered a flightless foot-propelled diving duck and represents the earliest example of flight loss in Anatidae. We carried out a comparative and morphometric descriptive study of different species of anseriforms with special attention to divers, to evaluate which is the expected intraspecific size variation within anatids to make an assignment of materials with a greater degree of certainty. Our results allow us to state that one coracoid, five humeri, two carpometacarpi, 12 femora, eight tibiotarsi, and eight tarsometatarsi can be assigned to the species. Consequently, it was possible to make a more detailed description and amend the original diagnosis. http://dx.doi.org/10.5710/AMGH.24.05.2019.3199

Field evidence of interpopulation variation in oocyte size of a marine invertebrate under contrasting temperature and food availability

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 619:69-84 (2019) - DOI: https://doi.org/10.3354/meps12959 Field evidence of interpopulation variation in oocyte size of a marine invertebrate under contrasting temperature and food availability Louis A. Gosselin1,*, Ramon Gallego2, Josefina Peters-Didier2, Mary A. Sewell2 1Department of Biological Sciences, Thompson Rivers University, 805 TRU Way, Kamloops, BC V2C 0C8, Canada 2School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand *Corresponding author: lgosselin@tru.ca ABSTRACT: In marine invertebrates with planktotrophic larvae, modelling studies predict that water temperature and food availability are the primary factors influencing oocyte size, with large oocyte sizes being favoured by cold water and low food availability. We examined intraspecific variation in oocyte size in the polychaete Spirobranchus cariniferus in populations from the East and West Coasts of New Zealand’s North Island, which differ in temperature and food availability during the reproductive season: the East Coast has consistently warmer seawater temperatures throughout the summer and higher phytoplankton abundance in late summer than the West Coast. A cross-fertilization experiment and DNA sequencing confirmed that Spirobranchus populations on both coasts belong to the same species. Then, analyses of S. cariniferus oocytes from 5 sites per coast revealed that the West Coast population produces oocytes that are on average 14% larger and contain up to 41% more triacylglycerols (TAGs) than the East Coast population. West Coast S. cariniferus oocytes also developed into larger larvae that reached competence 22% sooner than East Coast oocytes and larvae. These intraspecific comparisons of East and West Coast S. cariniferus populations reveal oocyte size to differ substantially even among populations that are probably not fully isolated, consistent with predictions of life history models. We estimate that genetic divergence may be responsible for up to 58% of the difference in oocyte size between East and West Coast populations, and that oocyte size may be subject to local adaptation to temperature and, to a lesser extent, food availability differences between coasts. KEY WORDS: Offspring size · Life history strategy · Maternal provisioning · Egg size · Biogeography · Phenotypic plasticity · Environmental effects · Genetic effects Full text in pdf format Supplementary material PreviousNextCite this article as: Gosselin LA, Gallego R, Peters-Didier J, Sewell MA (2019) Field evidence of interpopulation variation in oocyte size of a marine invertebrate under contrasting temperature and food availability. Mar Ecol Prog Ser 619:69-84. https://doi.org/10.3354/meps12959 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 619. Online publication date: June 04, 2019 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2019 Inter-Research.

Exploring the Role of Insulin Signaling in Relative Growth: A Case Study on Wing-Body Scaling in Lepidoptera.

Adult forms emerge from the relative growth of the body and its parts. Each appendage and organ has a unique pattern of growth that influences the size and shape it attains. This produces adult size relationships referred to as static allometries, which have received a great amount of attention in evolutionary and developmental biology. However, many questions remain unanswered, for example: What sorts of developmental processes coordinate growth? And how do these processes change given variation in body size? It has become increasingly clear that nutrition is one of the strongest influences on size relationships. In insects, nutrition acts via insulin/TOR signaling to facilitate inter- and intra-specific variation in body size and appendage size. Yet, the mechanism by which insulin signaling influences the scaling of growth remains unclear. Here we will discuss the potential roles of insulin signaling in wing-body scaling in Lepidoptera. We analyzed the growth of wings in animals reared on different diet qualities that induce a range of body sizes not normally present in our laboratory populations. By growing wings in tissue culture, we survey how perturbation and stimulation of insulin/TOR signaling influences wing growth. To conclude, we will discuss the implications of our findings for the development and evolution of organismal form.

Blue grama grass genotype affects palatability and preference by semi-arid steppe grasshoppers

The semi-arid shortgrass steppe ecosystem of North America is dominated by blue grama grass (Bouteloua gracilis), a species with substantial intraspecific variability, ecological significance, and economic value. Yet no studies have addressed within species differences in blue grama palatability or insect herbivore preference with respect to plant traits. We performed an experimental study to test the palatability and preference of two blue grama genotypes, wild type versus cultivar, by grasshopper herbivores in the Gomphocerinae subfamily. We found strong evidence that cultivar blue grama was more palatable than wild type and that grasshoppers preferred cultivar plants. Although we could not detect differences in silica content between the two types, we found that cultivar plants were larger, had lower water content, and surprisingly, had reduced nutrient value (greater C:N). These results suggest that intraspecific variation in blue grama size and water content could influence feeding choices by this group of grasshoppers. Conservation managers will have to consider such variation when considering how remnant and restored prairies might be affected by these arthropod herbivores.

Corrigendum: Inter- and Intra-specific variation in egg size among reef fishes across the Isthmus of Panama

Corrigendum: Inter- and Intra-specific variation in egg size among reef fishes across the Isthmus of Panama

Taxonomic revision of Cypridopsis silvestrii comb. nov. (Ostracoda, Crustacea) from Patagonia, Argentina with morphometric analysis of their intraspecific shape variability and sexual dimorphism.

In this study we redescribe an ostracod species belonging to the subfamily Cypridopsinae Kaufmann, 1900, sampled in seven localities of northern and southern Patagonia, Argentina. A new taxonomical combination is proposed, Cypridopsis silvestrii comb. nov., based on detailed description of females and the first descriptions of males. Cypridopsis silvestrii occurred on a wide geographical distribution range, from 40º to 48º S latitude, as well as broad environmental tolerance ranges. We evaluated morphological variations in two populations of C. silvestrii from northern (El Toro lake) and southern (El Sello lake) Patagonia, with contrasting limnological conditions. El Toro is a small shallow lake with high salinity waters and El Sello is a large deep lake with lower salinity. Based on morphometric analysis, our results showed intraspecific variation in valve shape and size between populations. Sexual dimorphism in El Toro population was identified through morphometric analyses. Additionally, comparison of valve outlines in living and subfossil individuals from El Toro lake allowed specimens previously described as juveniles of Eucypris fontana (Graf, 1931) to be identified as adults of C. silvestrii comb. nov. The present contribution increases knowledge of the taxonomic identity, the ecological requirements and the geographical distribution of C. silvestrii, and shows that morphometric analyses are a feasible and useful tool for exploring intraspecific shape differences and assisting in taxonomic identification. Furthermore, the results presented herein provide tools for C. silvestrii identification in paleolimnological studies, and emphasize the usefulness of studying living representatives for clarification of the taxonomic status of species widely distributed in Quaternary sediments.