A quarter of a century succession of epigaeic beetle assemblages in remnant habitats in an urbanized matrix (Coleoptera, Carabidae)

We studied the long-term (23-24 years) species turnover and succession of epigaeic beetle assemblages (Coleoptera: Carabidae, incl. Cicindelinae) in three remnant habitats [cottonwood (Populus spp.) and oak (Quercus spp.) stands, and old fields] that are embedded within highly urbanized areas in central Minnesota. A total of 9,710 beetle individuals belonging to 98 species were caught in three sampling years: 1980, 1981 and 2005 in pitfall traps in identical locations within each habitat. Results indicate that there were 2-3 times greater trap catches in 2005 than in 1980 (cottonwood and oak stands, and old fields) and 1.4-1.7 times greater species diversity of beetles in 2005 than in the 1980-1981 suggesting increased habitat association by beetles over time. Although there were no significant differences in catches between 2005 and 1981 (only cottonwood stands and old fields), there was a trend where more beetles were caught in 2005. At the species-level, 10 times more of an open-habitat carabid species, Cyclotrachelus sodalis sodalis LeConte, was caught in 2005 than in 1980. However, trap catches of five other abundant carabid species [Pterostichus novus Straneo, Platynus decentis (Say), Platynus mutus (Say), Calathus gregarius (Say), and Poecilus lucublandus lucublandus (Say)] did not change indicating population stability of some beetle species. These remnant habitats were increasingly colonized by exotic carabid species as Carabus granulatus granulatus Linneaus, Clivina fossor (Linneaus) and Platynus melanarius (Illiger), that were trapped for the first time in 2005. Species composition of epigaeic beetles was quite distinct in 2005 from 1980 with 39 species reported for the first time in 2005, indicating a high turnover of assemblages. At the habitat-level, greatest species diversity was in cottonwood stands and lowest was in old fields, and all habitat types in 2005 diverged from those in 1980s, but not cottonwood stands in 1981. As our sampled areas are among some of the last remnants of the original oak savanna habitats in central Minnesota, we hypothesize that conservation of these sites may be critical to maintaining epigaeic beetle assemblages under increased urbanization pressure.     

Abundance and diversity of ground-dwelling arthropods of pest management importance in commercial Bt and non-Bt cotton fields

The modified population dynamics of pests targeted by the Cry1Ac toxin in Bacillus thuringiensis (Bt) transgenic cotton (Bt cotton) and possible reduced insecticide use in these transgenic varieties may exert a variety of effects on ground‐dwelling predator communities. A survey of ground‐dwelling arthropods was carried out weekly each of 3 years (during the cropping season) in commercial Bt and non‐Bt cotton fields. Sixty‐five taxa of ground‐dwelling arthropods (carabids, cicindelines, staphylinids, dermapterans, heteropterans and araneids) of importance for cotton pest management were recorded in the survey. Species abundance and dynamics across seasons were evaluated with univariate analysis of variance for higher taxa or multivariate principal response curve analysis for the whole community of 65 taxa. Diversity and richness indices and cumulative species curves also were calculated. The analyses demonstrated no differences in the ground‐dwelling arthropod communities between cotton types. One araneid species, Pardosa pauxilla, comprised ～80% of all araneids, Labidura riparia comprised ～96% of all dermapterans, Megacephala carolina comprised ～97% of cicindelines and four carabid species (Selenophorus palliatus, Apristus latens, Harpalus gravis and Anisodactylus merula) comprised ～80% of carabid species. M. carolina outnumbered all other collected species in each of the 3 years. When only predatory carabid species were considered, A. merula, Calosoma sayi, Harpalus pennsylvanicus and Stenolophus ochropezus were predominant and numbers trapped were similar between cotton types. The abundance of dermapterans, staphylinids, araneids and heteropterans varied among sample dates and across seasons but did not differ between cotton types. The frequent capture of M. carolina, S. palliatus and P. pauxilla in all fields and seasons in both cottons suggests that these species may be important for monitoring further changes in local communities as result of agricultural practices.     

The blackburni/murchisona species complex in Australian Pseudotetracha (Coleoptera: Carabidae: Cicindelinae: Megacephalini): evaluating molecular and karyological evidence

Our phylogenetic analysis of three endemic species of the Australian tiger beetle genus Pseudotetracha (Fleutiaux, 1864) from South Australia used sequences of two fragments of the mitochondrial genes 16S rRNA and cytochrome oxidase III. A matrix for each gene and two combined matrices were constructed. We compared these three riparian species, together with data from nine taxa of this genus available in GenBank, using parsimony and Bayesian methods. These molecular results are in agreement with the phylogenetic hypothesis for the blackburni/murchisona species complex previously proposed based on morphology, whereas other recent molecular analyses have questioned the existence of this species complex. In all of our analyses, samples of P. blackburni divided into two statistically supported clades, one of which is more closely related to P. mendacia and P. pulchra than to the other P. blackburni clade. This suggests the existence of a cryptic new species. Additionally, we analysed chromosomes of the second metaphase cells of members of the two clades. The observations showed different karyotypes as blackburni‐1 has two types of second meiotic metaphase cells with 11 and 12 chromosomes, whereas in blackburni‐2, all cells have 12 chromosomes, adding evidence for the putative existence of two species.     

Molecular genetics of <Emphasis Type="Italic">Cicindela (Cylindera) terricola</Emphasis> and elevation of <Emphasis Type="Italic">C. lunalonga</Emphasis> to species level,with comments on its conservation status

Cicindela (Cylindera) terricola Say is one of the most widespread and variable species of Nearctic Cicindelidae with six recognized subspecies. Cicindela t. lunalonga Schaupp (1884) is known from few museum specimens collected prior to 1979. The goal of this study was to resolve the uncertain taxonomic status of C. t. lunalonga using mitochondrial DNA analysis of cytochrome b and cytochrome oxidase subunit I and determine its conservation status. In phylogenetic reconstruction using distance and parsimony methods, all members of the terrricola group were recovered as monophyletic and embedded within outgroup species of the subgenus Cylindera, while C. lunalonga was recovered as sister to all other members of the C. terricola clade. Cicindela lunalonga exhibited an exceptionally high (mean of 6.36%) pairwise sequence divergence for both genes against all C. terricola surveyed. For the cytochrome oxidase subunit I alone the pairwise divergence was 3.9–4.8% (4.58% avg.). The lowest divergences were between C. lunalonga and C. terricola subspecies of the American southwest (C. t. cinctipennis and C. t. kaibabensis), rather than with the closest geographic neighbors (C. t. imperfecta). We conclude that based on strict monophyly and pairwise sequence divergence, C. lunalonga is a distinct species. Our study of museum specimens and extensive field surveys suggest this species has been extirpated from all sites in the San Joaquin Valley and perhaps all but one of the historic sites throughout its range. Thus, it should be considered for Federal listing as an endangered species.