Latest Articles from Journal of Orthoptera Research Latest 2 Articles from Journal of Orthoptera Research https://jor.pensoft.net/ Fri, 29 Mar 2024 03:16:22 +0200 Pensoft FeedCreator https://jor.pensoft.net/i/logo.jpg Latest Articles from Journal of Orthoptera Research https://jor.pensoft.net/ Epigenetic and genetic variation between two behaviorally isolated species of Neoconocephalus (Orthoptera: Tettigonioidea) https://jor.pensoft.net/article/28888/ Journal of Orthoptera Research 28(1): 11-19

DOI: 10.3897/jor.28.28888

Authors: Gideon Ney, Johannes Schul

Abstract: Epigenetic variation allows for rapid changes in phenotypes without alterations to nucleotide sequences. These epigenetic signatures may diverge over time among isolated populations. Epigenetic incompatibility following secondary contact between these populations could result in the evolution of reproductive isolating mechanisms. If epigenetic incompatibility drove the evolution of species isolating mechanisms, we expect to see significant epigenetic differentiation between these species. Alternatively, epigenetic variation could be the result of predominantly environmental variables and not align along species boundaries. A methylation sensitive amplified fragment length polymorphism analysis was performed on individuals of the closely related katydid species Neoconocephalus robustus and N. bivocatus. We observed significant variation in total methylation levels between species. However, genetic differentiation remained larger than epigenetic differentiation between species groups. We measured a significant correlation between the epigenetic and genetic distance between individuals. Epigenetic differentiation is therefore likely the result of an interaction between genetic and epigenetic loci and not a mechanism for species differentiation. We therefore did not find evidence to support our hypothesis of an epigenetically mediated mechanism for speciation between N. robustus and N. bivocatus.

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Research Article Fri, 17 May 2019 18:59:01 +0300
Fine-scale interactions between habitat quality and genetic variation suggest an impact of grazing on the critically endangered Crau Plain grasshopper (Pamphagidae: Prionotropis rhodanica) https://jor.pensoft.net/article/15036/ Journal of Orthoptera Research 27(1): 61-73

DOI: 10.3897/jor.27.15036

Authors: Sylvain Piry, Karine Berthier, Réjane Streiff, Sandrine Cros-Arteil, Antoine Foucart, Laurent Tatin, Linda Bröder, Axel Hochkirch, Marie-Pierre Chapuis

Abstract: The Crau Plain grasshopper, Prionotropis rhodanica Uvarov, 1923 (Orthoptera: Pamphagidae: Thrinchinae), is a rare grasshopper species endemic to the Crau Plain, a steppic habitat in France with unique floristic and faunistic communities. During recent decades, the area covered by these steppic grasslands has been highly reduced and fragmented due to the development of irrigation-based agriculture, roads, as well as industrial and military complexes. The restricted distribution, low population density and poor dispersal ability of P. rhodanica, combined with the destruction of its habitat, has led to the classification of this species as critically endangered in the IUCN Red List of Threatened Species. Decreases in habitat quality due to intensive grazing in the remnant grassland patches constitute an additional threat for P. rhodanica that can impact population dynamics at a relatively small-scale. In this work, we focused on a small area of about 3 km2 occupied by one of the largest subpopulations observed in 2000–2001. We conducted a single-time snapshot intensive survey of grasshopper density and genetic variation at 11 microsatellite markers. We used a recent method, MAPI, to visualize the spatial genetic structure as a continuous surface and to determine, with the simultaneous use of spatial cross-correlograms, whether the normalized difference vegetation index, which informs on the balance between vegetation productivity and grazing intensity, can explain grasshopper population structure at such a fine scale. We found that both population density and gene flow were strongly and positively correlated to habitat quality (higher productivity of grasslands and/or lower sheep grazing). The spatial scales of interaction between these variables were estimated to be highly similar, in the range of 812–880 meters. This result suggests that P. rhodanica is very sensitive to the quality of the grasslands it inhabits.

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Research Article Tue, 12 Jun 2018 16:44:16 +0300