Substrate relations of the African wood‐burrowing mayfly Povilla adusta Navás (Ephemeroptera,Polymitarcyidae)

Colonization of an artificial substrate (polyurethane foam) by nymphs of the wood‐burrowing mayfly Povilla adusta was studied in a natural West‐African lake (Opi Lake). Nymphs readily colonized the substrate in densities up to 11,000 m^‐2 (early instars) and at depths ≤ 1.5 m. Blocks with rough surfaces and those in close proximity to oviposition sites near‐shore, had larger densities of nymphs than did those with smooth surfaces or those placed off‐shore. The upper surfaces of submerged blocks had smaller numbers of larger nymphs than did lower surfaces. Differences in the abundance of periphyton on the various surfaces may account for some of these patterns. The generation time of P. adusta is estimated to be three months in Opi Lake.     

Fine structure of the midgut of Sinopanorpa tincta (Navás) (Mecoptera: Panorpidae)

Fine structure of the midgut and degeneration of the midgut epithelium of the scorpionfly Sinopanorpa tincta (Navás) adults were investigated using light microscopy and scanning and transmission electron microscopy. The results show that the tubular midgut lacks gastric caeca and is composed of an outer longitudinal and an inner circular muscle layer, a basal lamina, an epithelium and a lumen from the outside to inside. A peritrophic membrane was not found in the lumen. A mass of nodules was observed on the surface of the basal lamina. Three types of cells were recognized in the epithelium: digestive, secretory, and regenerative cells. The digestive cells contain irregular-shaped infoldings in the basal membrane and two types of microvilli in the apical membrane. The secretory cells are characterized by irregular shape and large quantities of secretory granules in the basal cytoplasm. The regenerative cells are triangular in shape and distributed only in the nodules. The epithelial cells are degenerated through programmed cell-death mechanisms (apoptosis and necrosis). The type, function, and degeneration of the epithelial cells of the midgut are briefly discussed.     

The life cycle of the Maghrebian endemic Ecdyonurus rothschildi Navás, 1929 (Ephemeroptera: Heptageniidae) and its potential importance for environmental monitoring

Limnology - North African streams and rivers face multiple anthropogenic stressors, and their aquatic fauna is rapidly dwindling before comprehensive knowledge of their distribution and ecology has...     

Description of the larva of Kempnyia colossica (Navás) (Plecoptera: Perlidae) with biological notes

In this paper, the larva of Kempnyia colossica (Navás 1934) is described based on material collected in Parque Estadual Intervales, São Paulo State, and biological notes are presented.     

Description of the male drumming signals of Besdolus bicolor (Navás 1909) (Plecoptera: Perlodidae)

The call of the male of Besdolus bicolor, produced by percussion or drumming, is described for the first time. It represents the first recorded and analyzed signal for the genus Besdolus. It consists of a repetition of two or three beat groups, with each group composed by two (rarely three) beats, and with very constant interbeat intervals and intergroup intervals (mean 0.037 seconds and 0.213 seconds, respectively). The call pattern exhibited by this species can be catalogued as an ancestral percussive signal.     

Ultrastructure of male accessory glands in the scorpionfly Sinopanorpa tincta (Navás, 1931) (Mecoptera: Panorpidae)

The ultrastructure of male reproductive accessory glands was investigated in the scorpionfly Sinopanorpa tincta (Navás, 1931) (Mecoptera: Panorpidae) using light and transmission electron microscopy. The male accessory glands comprise one pair of mesodermal glands (mesadenia) and six pairs of ectodermal glands (ectadenia). The former opens into the vasa deferentia and the latter into the ejaculatory sac. The mesadenia consist of a mono-layered elongated columnar epithelium, the cells of which are highly microvillated and extrude secretory granules by means of merocrine mechanisms. The epithelium of ectadenia consists of two types of cells: the large secretory cells and the thin duct-forming cells. These two types of cells that join with a cuticular duct constitute a functional glandular unit, corresponding to the class III glandular cell type of Noirot and Quennedey. The cuticular duct consists of a receiving canal and a conducting canal. The secretory granules were taken up by the receiving canal and then plunged into the lumen through the conducting canal.     

Side Effects of Neem Oil on the Midgut Endocrine Cells of the Green Lacewing Ceraeochrysa claveri (Navás) (Neuroptera: Chrysopidae)

We described the ultrastructure of Ceraeochrysa claveri (Navás) midgut endocrine cells in larva, pupa, and adult, and evaluated the side effects of ingested neem oil, a botanical insecticide obtained from the seeds of the neem tree (Azadirachta indica), on these cells. During the larval period, C. claveri were fed (ad libitum) Diatraea saccharalis (F.) eggs treated with neem oil at concentrations of 0.5%, 1%, or 2%. Transmission electron microscopy showed that two subtypes of endocrine cells, namely granular and vesicular, occurred in the midgut epithelium during the three stages of the life cycle. Both cell types did not reach the midgut lumen and were positioned basally in the epithelium. The endocrine cells did not show extensive infoldings of the basal plasma membrane, and there were numerous secretory granules in the basal region of the cytoplasm. In the granular endocrine cells, the granules were completely filled with a dense matrix. In the vesicular endocrine cells, the main secretory products consisted of haloed vesicles. Ultrastructural examination indicated that only the granular endocrine cells exhibited signs of morphologic changes of cell injury present in all life cycle stages after the larvae were chronically exposed to neem oil by ingestion. The major cellular damage consisted of dilatation and vesiculation of the rough endoplasmic reticulum and the development of smooth endoplasmic reticulum and mitochondrial swelling. Our data suggest that cytotoxic effects on midgut endocrine cells can contribute to a generalized disruption of the physiological processes in this organ due to a general alteration of endocrine function.     

First record of the genus Bankisus Navás, 1912 in China, with the description of a new species (Neuroptera, Myrmeleontidae)

A new species of Bankisus Navás, 1912,(Bankisus sparsussp. n.)is described and illustrated with the genus newly recorded from China. A key to species of Bankisus is provided.     

The systematic position of the Miocene grebe Thiornis sociata Navás

Evidence is presented to show that dimensions and proportions which may vary with size are not valid characters for determining the generic placement of grebe species; that there is no valid reason for placing Thiornis sociata in the genus Podiceps; that if this species belongs in any Recent genus it is best placed in Tachybaptus, and that it is best retained in Thiornis pending further study.     

Nomenclatorial changes and redescriptions of three of Navás' Leucochrysa (Nodita) species (Neuroptera, Chrysopidae)

Three species that Navás described - Leucochrysa (Nodita) azevedoi Navás, 1913, Leucochrysa (Nodita) camposi (Navás, 1933) and Leucochrysa (Nodita) morenoi (Navás, 1934) - have received recent taxonomic attention. All three have many similar external features; indeed Navás himself, as well as subsequent authors, have confused the species with each other. Here, (a) misidentifications are corrected; (b) a neotype of Leucochrysa azevedoi is designated; (c) Leucochrysa (Nodita) morenoi, previously synonymized with Leucochrysa (Nodita) camposi, is recognized as a valid species [Reinstated status] All three species are redescribed and illustrated, with special emphasis on the types. Leucochrysa (Nodita) azevedoi was found to be relatively common in agricultural areas along Brazil's Atlantic coast. The two other species are known only from their type localities: Leucochrysa (Nodita) camposi - coastal Ecuador, and Leucochrysa (Nodita) morenoi - Quito, Ecuador.     

Nymphal feeding of Leptophlebiidae (Insecta: Ephemeroptera) in the Caño Paso del Diablo,Venezuela

The food habits of aquatic nymphs of 12 species of the family Leptophlebiidae were determined in a tropical intermittent stream in Venezuela. Three monthly samples of aquatic insects were taken from January to June in 1989. Two hundred and twenty-five stomach contents were analyzed. The results obtained were compared by the functional feeding groups classification. Species of the Thraulodes and Farrodes genera show significant differences in their diets.     

Evaluation of the Boll Weevil Anthonomus grandis Boheman (Coleoptera: Curculionidae) Suppression Program in the State of Goiás, Brazil

The boll weevil Anthonomus grandis Boheman (Coleoptera: Curculionidae) is the most important cotton pest in Brazil. A large-scale field-testing of a Boll Weevil Suppression Program (BWSP) was implemented to assess its technical and operational feasibility for boll weevil suppression in the state of Goiás, Brazil. The pilot plan focused on 3,608 ha of cotton during the 2006/2007 and 6,011 ha in the 2007/2008 growing seasons; the areas were divided into four inner zones with an outer buffer zone. We analyzed data on boll weevil captures using pheromone traps installed in the BWSP fields, on the detection of the first insect and the first damaged floral bud, greatest damage, and number of insecticide applications. The nonparametric Mann–Whitney U test was used to evaluate the differences between presuppression and suppression years. Fourteen pheromone-baited trapping evaluations were used to compare the weevil populations from 2006/2007 and 2007/2008 growing seasons. The BWSP regime reduced in-season boll weevil captures from 15- to 500-fold compared to presuppression levels in the preceding year. The low capture rates were related to delays in infestation and damage by weevils. The smaller population size measured by trapping and field monitoring reduced the number of required insecticide treatments. The BWSP strategy was efficient in suppressing populations of this pest and is a viable program for cotton production in subtropical and tropical regions, with long-term economic and environmental benefits.     

Life cycle and production of Campsurus notatus (Ephemeroptera,Polymitarcyidae) in an Amazonian lake impacted by bauxite tailings (Pará, Brazil)

A synoptic survey of the distribution and abundance of occurrence of bloom-forming Cyanobacteria in 55 lakes in the Republic of Ireland revealed strong positive correlations with the traditional trophic gradient. Analysis of the data shows that the perceived trophic state may be correctly viewed as a function of phosphorus availability. The distribution of dominant bloom-forming Cyanobacteria is strongly related to the geology of the catchments and the incidence of significant bicarbonate buffering.     

After the fire: the end of a house life-cycle at the Iron Age site of Nabás (North-western Iberia)

Vegetation History and Archaeobotany - The existence of a fire event at the Iron Age hillfort of Nabás, which is located on the southern bank of the Ría de Vigo (Galicia, NW of the...