Vladimir D. Ivanov

Identification of a Sex Pheromone Produced by Sternal Glands in Females of the Caddisfly Molanna angustata Curtis

In the caddisfly Molanna angustata, females produce a sex pheromone in glands with openings on the fifth sternite. Gas chromatographic analyses of pheromone gland extracts with electroantennographic detection revealed four major compounds that stimulated male antennae. These compounds were identified by means of gas chromatography–mass spectrometry and enantioselective gas chromatography as heptan-2-one, (S)-heptan-2-ol, nonan-2-one, and (S)-nonan-2-ol in the approximate ratio of 1:1:4:10, respectively. Field tests showed that the mixture of the two alcohols was attractive to males whereas addition of the corresponding ketones reduced trap catches. The sex pheromone of M. angustata, a species in the family Molannidae within the suborder Integripalpia, is similar to the pheromones or pheromone-like compounds previously reported from six other trichopteran families, including members of the basal suborder Annulipalpia. This suggests that minimal evolutionary change of the pheromone chemistry has taken place within the leptoceroid branch of integripalpian Trichoptera compared to the ancestral character state.

Structure of antennal sensilla in the caddisfly genus Rhyacophila pictet (Trichoptera, Rhyacophilidae)

Microstructure and distribution of sensilla were studied in 25 species of caddisflies of the family Rhyacophilidae for the first time. Comparative analysis allowed 13 sensilla types to be identified in members of this family: long grooved trichoid, curved trichoid, chaetoid, mushroom-like pseudoplacoid, forked pseudoplacoid, leaf-like pseudoplacoid, dissected pseudoplacoid, multiforked pseudoplacoid, styloconic, auricillic, coronal, basiconic sensilla, and Böhm’s bristles. The largest variations were found in the pseudoplacoid sensilla. Dissected, leaflike, auricillic, and multiforked sensilla were discovered in the order Trichoptera for the first time. Curved trichoid sensilla can be grouped or assembled into sensory fields. The total number of sensilla per antennal segment decreases towards the antenna apex. Data on the structural diversity of sensilla in groups of fast-evolving species suggest the participation of sensilla structures in the speciation processes.

Interrelation Between the Interaction Parameter and the Width of the Adsorption Voltammetric Peak

It is known that the width of adsorption of a voltammetric peak is defined by lateral interactions in adsorption layer, so the peak width may be a key to intensity of these interactions. Correlation between the width of the peak and interaction parameter G has been examined in details. It is impossible to find the exact equation setting G as a direct function of peak width. Approximate equations are proposed to calculate G from the peak width with high accuracy in a wide range of G values. G value can be useful not only for characterization of lateral interactions in adsorbed layer (for finding adsorption isotherm parameters), but also for quick estimation of adsorption of electroactive substance.

The Structure and Evolution of the Apical Sensory Zone Structures in the Maxillary and Labial Palps of Caddisflies (Trichoptera)

A comparative morphological study of the apical regions of palps in Trichoptera from different evolutionary lines of the order was carried out, and a comparison was made with representatives of Lepidoptera and Mecoptera. Light and scanning electron microscopy methods were used to study the structure of palpal apices in 81 species of the order Trichoptera, 6 of Lepidoptera, and 2 species of Mecoptera. As a result, 11 types of sensilla were identified on the terminal palpal segments, and highly differentiated apical sensory zones with thick short basiconic sensilla were found on the maxillary and labial palps. The presence of an apical sensory zone in caddisflies and related orders is recognized as a plesiomorphic character.

Comparison of sensory structures on the antenna of different species of Philopotamidae (Insecta: Trichoptera)

Structure and distribution of sensilla were studied in sixteen species of the caddisfly family Philopotamidae. Their antennae bear numerous curved trichoid and pseudoplacoid sensilla and fewer coronal, styloconic and chaetoid sensilla on the flagellar segments. The most numerous pseudoplacoid sensilla have non-specific localization. The curved trichoid sensilla form clusters ventrally on each antennal segment. Sensilla belonging to coronal, styloconic and chaetoid types have specific positions. Long grooved trichoid sensilla are located nonspecifically in all the studied species. The average number of sensilla per segment decreases from the proximal to distal part of the flagellum. Scapus and pedicellum are devoid of most types of sensilla, however, they bear the Böhm bristles and long trichoid sensilla. A positive correlation between antenna dimensions and its cuticular structures is found.

A new species of Tinodes (Trichoptera: Psychomyiidae) from Madagascar

The genus Tinodes (Psychomyiidae) has a wide distribution in the Eastern Hemisphere with the richest species assemblages in the Oriental and southern parts of the Western Palearctic regions. In comparison with the species assemblages in those regions, diversity of the African species of this genus is relatively poor. A brief review of the 10 then-known Afrotropical species belonging to the genus Tinodes was published by Johanson & Oláh (2007) together with descriptions of 14 new species. Some of these new species came from the Eastern African Arc of crystalline mountains, although 5 species have been found in Madagascar and the Comoros where no species of the genus Tinodes have been known previously. These new findings suggest continuing poor knowledge of the Afrotropical faunas where many species escaped descriptions until the beginning of the XXI century.

New data on caddisflies (Insecta: Trichoptera) from Lombok (Indonesia) with descriptions of two new species.

Knowledge of caddisflies of the Sunda Islands was insufficiently known until recent times; a survey of the caddis fauna of this area was given by Malicky (2010) and some more data were published recently (Malicky et al. 2011). A summary on the particular features of Trichoptera from 3 adjacent islands, Bali, Lombok, and Java, were given by Malicky et al. 2014. These were the first surveys of the local caddisfly fauna of Lombok, listing 60 species and anticipating that more species should occur there. It was shown that the caddisfly fauna of these islands is largely homogenous and there are not sufficient differences between Bali and Lombok to support the hypothesis of Wallaces line (Malicky et al. 2014). The comparative analysis showed continuous impoverishment of the caddis fauna from the Asian continent over the chain of islands from west to east. Unfortunately, the Trichoptera fauna of the easternmost Sunda Islands, Sumba, Sumbawa, Flores, Timor, and the Moluccas is almost unstudied. The Trichoptera fauna of these islands is, according to present knowledge, Asian. Since the previous material from Lombok was collected only once at the end of the wet season, it was necessary to have more data from other seasons. Hence we made another effort to sample caddisflies in this area. As a result, 8 more species were found, 2 of which were new for science. The updated list (Table 1) includes now 68 species.

Magnification of interferogram with the use of digital holography

The method of holographic interferometry with the increased sensitivity was applied for measurements of height of nano-steps (from 10 nm and higher) with standard uncertainty about 0.5 nm. The increasing of sensitivity is obtained by interference of waves with mutually complex conjugated phases.

Holographic nanointerferometer with digital magnification

The method of holographic interferometry with the increased sensitivity was applied for measurements of height of nano-steps (from 10 nm and higher) with standard uncertainty about 0.5 nm. The increasing of sensitivity is obtained by interference of waves with mutually complex conjugated phases.

Dynamic holographic interferometry with matrix LC modulator

The method of holographic intereferometry with increased sensitivity was applied for measurements of height of nanosteps (from 10 nm and higher) with standard uncertainty about 0.5 nm. The initial microinterferogram with fringes of equal width was obtained in Michelson micro-interferometer with nano-step sample in one of legs. This interferogram was registered by CCD–camera and the digital interference pattern was reproduced on matrix phase modulator with spatial resolution 30 lines/mm. The matrix phase modulator was placed at the output of the two-beam Mach-Zehnder interferometer and illuminated by two plane laser beams. These two beams diffracted on phase modulator, were focused and spatially filtered by the pinholes in (+ 1-st ) and (– 1-st ) orders of diffraction. The second digital interferogram with twofold increase of sensitivity was obtained on CCD–camera and so on. The increase of sensitivity was obtained due to the interference of waves with complex conjugated phases. One can obtain the interference of higher orders too if working with the nonlinear interferogram. It is possible to obtain any carrier fringe space frequency by using of two plane waves in the interferometer. The increase of sensitivity may be obtained in research of flatness less than λ/100, and topography of surfaces with height difference less than few nanometers as well.