Impact of Limited Dispersion Capacity and Natural Barriers on the Population Structure of the Grasshopper Ommexecha virens (Orthoptera: Ommexechidae).

The grasshopper Ommexecha virens Serville has low dispersion capacity, and it is regarded as a specialist, only being found in sandy, dry environments with high incidence of sunlight. Considering these aspects, we evaluated the diversity and genetic structure of O. virens natural populations using ISSR (Inter Simple Sequence Repeat) markers. The data pointed to low expected heterozygosity for some populations (HE = 0.06-0.09), probably a consequence of positive inbreeding, which is typical of species showing low or null dispersion indices. Moreover, significant genetic differentiation was observed (FST = 0.50 and GST = 0.51), as well as low number of migrants (Nm = 0.47), indicating that the populations are genetically differentiated. This is likely related to the limitation in dispersing and fragmentation of suitable environment localities colonized by O. virens. The populations of O. virens were structured in three genetic groups associated to different landscapes, revealing the presence of a secondary contact zone, possibly arisen from isolation followed by genetic divergence among populations and subsequent gene flow of divergent individuals of O. virens. At last, we found positive isolation by distance (IBD; r: 0.427; P: 0.025) which is an important factor, since it may be adding to the emergence of reproductive barriers among individuals of O. virens that have been experiencing isolation.

Dichotomius (Luederwaldtinia) schiffleri (Coleoptera: Scarabaeidae) mitochondrial genome and phylogenetic relationships within the superfamily Scarabaeoidea.

The mitochondrial DNA of Dichotomius (Luederwaldtinia) schiffleri was characterized and its phylogenetic position was reconstructed in Scarabaeoidea. This mitogenome presented 14,802 bp-long, richness in AT of 77.4% and 37 genes, including 13 protein-coding, 22 transfer RNAs, and two ribosomal RNAs. In addition, it was observed intergenic spacers and reading frame overlaps. The phylogenetic trees reconstructed from protein sequences provided best resolution, indicating Scarabaeinae and Aphodiinae as a sister groups, as previously reported in other molecular phylogenies.