Artifactual Motility of the Subcoxal Axis in a Model Insect Leg with Skew Joint Axes.

Kinematic reconstructions of joint angles during walking in stick insects revealed that the subcoxal axis (SCA) was neither firm during the step (it was movable), nor was its position matched to the line between articulation condyles. It has been demonstrated on kinematic models of a leg that the application of a simplified leg model for reconstruction caused an artifactual result: apparent movement of SCA and its drift from the real firm position. Simplified models assume that the plane where leg segments lie rotates about the SCA or at least the axis of joint rotation is perpendicular to the leg segment. Real legs have joints with non-parallel or non-orthogonal axes. Models considered in this article had an oblique arrangement of joint axes. Real or artifactual motility of CAS is discussed.

[Radionuclide transfer by migratory birds]. / Perenos radionuklidov pereletnymi ptitsami.

Evaluation of the zoogenic transfer of radionuclides from the 30-km zone around the Chernobyl NPP was necessary because of the enormous heavily polluted territory and mighty flow of migratory birds who tended to large rivers, the Dnieper and Pripyat. The integral estimate of the transferred amount was obtained as a product of three variables: the transfer factor (0.0077 m2/kg for 137Cs; 0.0107 m2/kg for 90Sr), the density of birds (0.002 kg/m2, at the mass of migrants about 5000 t per year), and the total fund of radionuclides throughout the territory. The upper estimated limit of the annual transfer rate was 5.5 Ci (2E + 11 Bq) for 137 Cs and 1.8 Ci (6.7E + 10 Bq) for 90 Sr. Restrictions of hunting are recommended within the northern part of the Kiev reservoir.

[Critical evaluation of the searching technic of the polarization-sensitive neurons of insects]. / Kriticheskii otsenka metoda poiska poliarizatsionno-chuvstvitel'nykh neironov u nasekomykh.

The demerit of the light stimulator used by the authors was the presence of lenses between the eye and the observed light source. Apart from the image of the aperture diaphragm, the images of some details and reflections were formed. The terminal lens of the stimulator and the eye optics can divide the main and secondary images of the retina. Therefore the reactions of insect neurons to polarized light described previously could be explored also as the responses to flickers in secondary images.

[Reactions of the directionally sensitive optical interneurons of insects to movement of a two-dimensional pattern]. / Reaktsiia direktsionno-chuvstvitel'nykh opticheskikh interneironov nasekomykh na dvizhenie dvumernykh uzorov.

The reactions to movements of two-dimensional patterns with the same average spatial period were compared in electrophysiological experiments. Directionally-sensitive neurons in connectives of dragonflies (fam. Libellulidae) were 1.5--2 times more sensitive to movement of "dissected" patterns (checkerboards, lattice of circles, stochastic pattern) than to vertical stripes. The power of optic signal in high-frequency domain in dissected patterns is 1.4--1.8 times higher, than in a striped pattern. It is assumed that high-frequency spatial filtering in dragonflies is provided by strong lateral inhibition in retinotopic projection. Dissected and striped patterns elicited identical reactions in directionally-sensitive neurons of the dronefly Eristalis tenax; the same was stated for the locomotory optokinetic reaction of the earty-boring dung beetle Geotrupes stercorosus.

[Insect interneurons sensitive to polarized light]. / Interneirony, chuvstvitel'nye k poliarizovannomu svetu, u nasekomykh.

Neurons responding with a rhythmic discharge to rotation of a polarization plane (frequency being 0.7 Hz) were found in the optic lobe of scarabaeids Geotrupes. Responses to a polarized light stimulus were compared with those evoked by light intensity modulation and with suspected responses to apparent rotatory movement of a filter. The polarization sensitivity of some observed neurons was about 2. The on-component of the response to polarization coincided with the horizontal position of the electric vector.

[Size of the binocular zone of the field of vision of insects]. / Razmery binokuliarnoi zony pelia zreniia u nasekomykh

The insects selected for measurements-- predators and anthophiles -- presumably possessed the ability of binocular estimation of distances. The margins of visual field and of the binocular zone in a compound eye could be traced by means of ophthalmological methods, such as observation of a pseudopupil or of a glow of ommatidia lit from inside. Predators as well as males of flies and drones, which intercept a point target against the sky, have the smallest binocular zone. They could not discover the distance to a target by binocular vision. Anthophiles have a broad binocular "window" pointing in antero--ventral direction; their binocular zone encloses 20--25% of facets. Predators hunting amidst the vegetation have the largest binocular zone (30--75%). The binocular zone of the eyes in the insects of large and middle size consists of 2--9 thousand of ommatidia.

[Visual interneurons, sensitive to the size of objects and the direction of their movement in dragonflies of the genus Sympetrum]. / Zritel'nye interneirony, chuvstvitel'nye k razmeru ob''ektov i napravleniiu dvizheniia, u strekoz roda Sympetrum

Experiments have been made on 4 dragonfly species -- Sympetrum vulgatum, S. flaveolum, S sanguineum, S. danae. A pair of neurons was found in the thoracic ganglia and connectives, which has symmetrical contralateral receptive fields. These neurons are selectively sensitive to swift upward motion of a target of 3--10 degrees in size. This type of response was originally described by Zenkin and Pigarev [1, 2]. The receptive field, 120X25 degrees in size, is oriented horizontally from the medial rim of the eye. The center of sensitivity has the following polar coordinates: 15 degrees laterally from the medial plane and 20 degrees above the equatorial one. The relation of detecting properties of the observed neurones to key stimuli which trigger hunting behaviour is discussed. It is suggested that filtration of single and small optic stimuli by specialized detector neurons results not from the processes in the own receptive field of the neuron, but from the interaction with other neurons which are sensitive to motion of large objects and complex patterns.