The karyotype and male meiosis, with a particular focus on the presence or absence of chiasmata between the homologs, were studied in the water boatman species Cymatia rogenhoferi (Fieber) and Cymatia coleoptrata (Fabricius) (Corixidae, Cymatiainae). It is shown that the species have 2n = 33 (28A+2m+X1X2Y) and 2n = 24 (20A+2m+XY) respectively, post-reduction of sex chromosomes, and achiasmate m...

Constraints on lake communities are complex and are usually studied by using limited combinations of variables derived from measurements within or adjacent to study waters. While informative, results often provide limited insight about magnitude of simultaneous influences operating at multiple scales, such as lake- vs. watershed-scale. To formulate comparisons of such contrasting influences, we...

A checklist of Heteroptera type specimens deposited in the collection of División Entomología, Museo de La Plata. It harbours type material of 1153 species belonging to 37 families (Enicocephalidae, Schizopteridae, Gerridae, Veliidae, Hydrometridae, Naucoridae, Belostomatidae, Nepidae, Corixidae, Notonectidae, Pleidae, Saldidae, Cimicidae, Polyctenidae, Nabidae, Miridae, Tingidae, Vianaididae, ...

BACKGROUND Trichocorixa verticalis verticalis, a native of North America, is the only alien corixid identified in Europe. First detected in 1997 in southern Portugal, it has spread into south-west Spain including Doñana National Park. Its impact on native taxa in the same area is unclear, but it is the dominant species in several permanent, saline wetlands. METHODOLOGY/PRINCIPAL FINDINGS We i...

We report on the results of a survey of the Nepomorpha of northern Tunisia, and list twenty-three species belonging to twelve genera and seven families: Nepidae, Ochteridae, Corixidae, Micronectidae, Naucoridae, Notonectidae, and Pleidae. These records are based on intensive field surveys during the year 2013 and examination of the entomological collections of the National Museum Natural Histor...

The fluid forces that govern propulsion determine the speed and energetic cost of swimming. These hydrodynamics are scale dependent and it is unclear what forces matter to the tremendous diversity of aquatic animals that are between a millimeter and a centimeter in length. Animals at this scale generally operate within the regime of intermediate Reynolds numbers, where both viscous and inertial...

Descriptions of the last three nymphal instars of the water boatman Sigara (Aphelosigara) tucma Bachmann (Hemiptera: Heteroptera: Corixidae) are provided, for the first time, for specimens collected in northern Argentina; the egg is redescribed. Adults and nymphs were collected in the field. The eggs were obtained by dissection from females. The immature stages were fixed for microscopic examin...