Project description:Altitudinal clines in body size can result from the effects of natural and sexual selection on growth rates and developing times in seasonal environments. Short growing and reproductive seasons constrain the body size that adults can attain and their reproductive success. Little is known about the effects of altitudinal climatic variation on the diversification of Neotropical insects. In central Mexico, in addition to altitude, highly heterogeneous topography generates diverse climates that can occur even at the same latitude. Altitudinal variation and heterogeneous topography open an opportunity to test the relative impact of climatic variation on body size adaptations. In this study, we investigated the relationship between altitudinal climatic variation and body size, and the divergence rates of sexual size dimorphism (SSD) in Neotropical grasshoppers of the genus Sphenarium using a phylogenetic comparative approach. In order to distinguish the relative impact of natural and sexual selection on the diversification of the group, we also tracked the altitudinal distribution of the species and trends of both body size and SSD on the phylogeny of Sphenarium. The correlative evidence suggests no relationship between altitude and body size. However, larger species were associated with places having a warmer winter season in which the temporal window for development and reproduction can be longer. Nonetheless, the largest species were also associated with highly seasonal environments. Moreover, large body size and high levels of SSD have evolved independently several times throughout the history of the group and male body size has experienced a greater evolutionary divergence than females. These lines of evidence suggest that natural selection, associated with seasonality and sexual selection, on maturation time and body size could have enhanced the diversification of this insect group.
Project description:Background matching and disruptive coloration are defense mechanisms of animals against visual predators. Disruptive coloration tends to evolve in microhabitats that are visually heterogeneous, while background matching is favored in microhabitats that are chromatically homogeneous. Controlling for the phylogeny, we explored the evolution of the coloration and the marking patterns in the sexual dichromatic and widely distributed neotropical grasshoppers of the genus Sphenarium. These grasshoppers represent an excellent model to investigate the evolution of cryptic coloration on insects due to the heterogeneity of the environments where they have evolved. We found a correlation between the grasshoppers' coloration and disruptive markings with the chromatic properties of their environments that was inferred by the levels of precipitation during the rainy season. The results suggest that colors and marking patterns could evolve due to predation pressures. Color in both sexes could offer camouflage that is not perfectly background matched to a single habitat but instead offers a degree of resemblance to multiple backgrounds. Moreover, we found that males and females chromatic properties differ between them and precipitation levels where the species are found. This suggests that the sexes have diverged in their response to the environments, favoring the evolution of sexual dichromatism in these grasshoppers.
Project description:The genus Pseudoheptascelio Szabó is redescribed and its species revised. We recognize four species: Pseudoheptascelio muesebecki Szabó, Pseudoheptascelio cornopis Masner, Pseudoheptascelio ticosp. n. and Pseudoheptascelio rexsp. n. The genus is found from Guatemala south to the Brazilian state of Rio Grande do Sul. The species Pseudoheptascelio cornopis is recorded as a parasitoid of the eggs of Cornops aquaticum (Bruner) on water hyacinth, Eichhornia crassipes (Mart.) Solms.
Project description:BackgroundGrasshoppers (Acridoidea, Orthoptera) are the dominant herbivores in grassland ecosystems worldwide. They can increase rangeland productivity by stimulating plant growth and accelerating nutrient cycling. This article presents a comprehensive checklist of grasshoppers in Mongolia. Until then, the available information was very scattered, based on old studies of Mongolian grasshoppers, recorded in a few international catalogues and databases, individual records and research work on agroecosystem communities. However, the available information on the composition of the Orthopteran fauna in Mongolia was sometimes unclear or non-existent and these dubious data were excluded from the present study. In addition, the grasshopper distribution analysis used the standardised personal collection of D. Altanchimeg. We also present a list of grasshoppers, as well as their distribution and abundance, in countries adjacent to Mongolia, such as Russia, China and South Korea. The surveys covered six types of natural zones: high mountain, taiga, forest-steppe, steppe, desert steppe and desert; desert steppe and steppe zones are the most widely distributed. We hope to have contributed significantly to the study of the distribution of grasshopper species in all these natural zones.New informationIn this study, a total of three families of Acridoidea belonging to eight subfamilies, 17 tribes, 52 genera and 128 species are reported for the various natural zones. The recorded species belong to eight subfamilies: Gomphocerinae are the most numerous with 56 species recorded, followed by Oedipodinae (51 species), Thrinchinae (nine species), Melanoplinae (six species), Calliptaminae (three species), Dericorythinae, Acridinae, Egnatiinae (one species each).
Project description:Although previous cytogenetic analysis of Pamphagidae grasshoppers pointed to considerable karyotype uniformity among most of the species in the family, our study of species from Armenia has discovered other, previously unknown karyotypes, differing from the standard for Pamphagidae mainly in having unusual sets of sex chromosomes. Asiotmethis turritus (Fischer von Waldheim, 1833), Paranocaracris rubripes (Fischer von Waldheim, 1846), and Nocaracris cyanipes (Fischer von Waldheim, 1846) were found to have the karyotype 2n♂=16+neo-XY and 2n♀=16+neo-XX, the neo-X chromosome being the result of centromeric fusion of an ancient acrocentric X chromosome and a large acrocentric autosome. The karyotype of Paranothrotes opacus (Brunner von Wattenwyl, 1882) was found to be 2n♂=14+X1X2Y and 2n♀=14+X1X1X2X2., the result of an additional chromosome rearrangement involving translocation of the neo-Y and another large autosome. Furthermore, evolution of the sex chromosomes in these species has involved different variants of heterochromatinization and miniaturization of the neo-Y. The karyotype of Eremopeza festiva (Saussure, 1884), in turn, appeared to have the standard sex determination system described earlier for Pamphagidae grasshoppers, 2n♂=18+X0 and 2n♀=18+XX, but all the chromosomes of this species were found to have small second C-positive arms. Using fluorescent in situ hybridization (FISH) with 18S rDNA and telomeric (TTAGG)n DNA repeats to yield new data on the structural organization of chromosomes in the species studied, we found that for most of them, clusters of repeats homologous to 18S rDNA localize on two, three or four pairs of autosomes and on the X. In Eremopeza festiva, however, FISH with labelled 18S rDNA painted C-positive regions of all autosomes and the X chromosome; clusters of telomeric repeats localized primarily on the ends of the chromosome arms. Overall, we conclude that the different stages of neo-Y degradation revealed in the Pamphagidae species studied make the family a very promising and useful model for studying sex chromosome evolution.
Project description:The karyotypes of three species of Pyrgomorphidae grasshoppers were studied: Zonocerus elegans (Thunberg, 1815), Pyrgomorpha guentheri (Burr, 1899) and Atractomorpha lata (Mochulsky, 1866). Data on karyotypes of P. guentheri and Z. elegans are reported here for the first time. All species have karyotypes consisting of 19 acrocentric chromosomes in males and 20 acrocentric chromosomes in females (2n♂=19, NF=19; 2n♀=20, NF=20) and X0/XX sex determination system. A comparative analysis of the localization of C-heterochromatin, clusters of ribosomal DNA, and telomere repeats revealed inter-species diversity in these cytogenetic markers. These differences indicate that the karyotype divergence in the species studied is not associated with structural chromosome rearrangements, but with the evolution of repeated DNA sequences.
Project description:Phymateus saxosus is a member of the family Pyrgomorphidae, Orthoptera. In this study, the complete mitochondrial genome (mitogenome) of P. saxosus was determined and analyzed. Assembled mitogenome sequence of P. saxosus is 15,672 bp in size, containing 37 genes and a control region. The gene orientation and arrangement of P. saxosus are identical to other species in the Pyrgomorphoidea family. The overall nucleotide composition is as follows: A (43.6%) > T (30.2%) > C (16.1%) > G (10.1%). Phylogenetic analysis suggested that P. saxosus forms sister groups with P. morbillosus, and the monophyly of Pyrgomorphidae is supported. In general, this study provided valuable genetic information for P. saxosus and explored the phylogenetic relationships in the family Pyrgomorphidae.
Project description:We reared Oedaleus asiaticus grasshoppers under four different single-plant diets to examine the relationships among diet, performance, stress, and transcription patterns. Grasshoppers fed only Artemisia frigida (Asteraceae) were stressed, as indicated by their lower growth, size, development, and survival, in comparison to grasshoppers fed on any of three grasses, Cleistogenes squarrosa, Leymus chinensis, or Stipa krylovii (all Poaceae). We then used transcriptome analysis to examine how gene expression levels in O. asiaticus were altered by feeding on these diets. Nymphs fed A. frigida had the largest variation in gene expression profiles with a total of 299 genes significantly up- or down-regulated compared to those feeding on the three grasses: down-regulated genes included those involved in cuticle biosynthesis, DNA replication, biosynthesis and metabolism of nutrition. The up-regulated genes included stress-resistant and detoxifying enzymes. GO and KEGG enrichment analysis also showed that feeding on A. frigida could down-regulate biosynthesis and metabolism related pathways, and up-regulate stress-resistant and detoxification terms and pathways. Our results show that diet significantly altered gene-expression, and that unfavorable, stressful diets induce more transcriptional changes than favorable diets. Altered gene-expression represents phenotypic plasticity, and many such changes appear to be evolved, adaptive responses. The ease and regularity by which individuals shift phenotypes via altered transcription suggests that populations consist not of similar, fixed phenotypes, but of a collection of ever-changing, divergent phenotypes.
Project description:To cope with life in the mountains, populations of the same species can exhibit substantial variability in their altitudinal migration patterns and phenotypes in response to local weather conditions. Studying such variability can provide valuable insights into how local populations respond to environmental challenges, and this information can be useful for conservation efforts in mountain ecosystems. Here, we used δ2H values of feathers and blood to evaluate latitudinal variation in altitudinal migration patterns and its possible links with body size, oxidative status, and exploratory behavior in 72 individuals of rufous-collared sparrow (Zonotrichia capensis) that breed at low and high elevations in the center (~33°) and south (~38°) of Chile. Our results show that both altitudinal migration patterns and oxidative status were significantly influenced by the latitude of breeding sites, while exploratory behavior was associated with elevation. Notably, we found that fast-explorer birds inhabiting low elevations in central Chile displayed higher levels of oxidative damage than slow-explorer birds. These outcomes underscore the possibility of local adaptations in response to diverse local environmental conditions in the Andes. We discuss the implications of latitude, elevation, and environmental temperature in shaping the observed patterns and highlight the significance of identifying local adaptations in mountain birds for better predicting their response to climate change and other challenges stemming from anthropogenic activities.