ber den Feinbau der Duftdr�sen von Feuerwanzen (Pyrrhocoris apterus L., Geocorisae): I. Mitteilung Zur funktionellen Morphologie der Dr�senzelle

Effects of aromatic compounds on movement activity of Pyrrhocoris apterus in the conditions of a laboratory experiment

In the conditions of an urban environment, insects, including Pyrrhocoris apterus (Linnaeus, 1758) (Hemiptera, Pyrrhocoridae), are subject to dozens of volatiles: solvents, food flavorings, cosmetic products. For firebugs, some attract them, some scare them off, and to some they are indifferent. In this article, in the conditions of laboratory experiment, we evaluated the influence of chemical substances on rates of movement of firebugs. Under the influence of the substances we studied, there occurred no significant increase or decrease in the activity of firebugs. The most significant effect on rates of movement of firebugs was exerted by solvent, white spirit and solvent 646 p – firebugs travelled 12 cm distance for 24.2%, 49.6% and 58.7% of the time the control group did. Movement activity of firebugs was insignificantly decreased by aromatic extracts Royаl milk extract, Butcher’s broom extract and chrysalis oil: firebugs travelled 12 cm distance for 132.7%, 135.2% and 146.8% of time the control group. Aromatic substances likely interact with receptors on antennae of firebugs, and therefore the insects need additional time for orienting reactions, deciding whether those substances signal presence of potential food objects in the accessibility zone.

Fine structural organization of the spermatheca in the cockroach, Periplaneta americana

The detailed structure of the cockroach spermatheca is described and discussed firstly as an example of an insect integumentary gland, and secondly, from the standpoint of its role in reproduction. The gland comprises a cortical rank of separate secretory units, each associated with an epithelial duct cell responsible for receiving secreted materials and transporting them through the cuticular intima lining the reproductive tract. Secretory activity is cyclic, and the probable mode of elaboration and release of secretory material is described, together with the fine structure of the markedly differing intimas associated respectively with the glandular and conducting units.

Structure of the tarsi in some Stenus species (Coleoptera, Staphylinidae): external morphology, ultrastructure, and tarsal secretion

SEM studies show that the differentiation among Stenus species with respect to the formation of the tarsi (wide bilobed vs. slender tarsomeres) takes place with a considerable augmentation of tarsal ventral setae in wide bilobed tarsomeres. The structural diversity of ventral tarsal setae among and within species is discussed with respect to 1) their different roles as mechanosensilla and tenent setae, respectively, and 2) the different selection pressures in terms of adhesive requirements along the longitudinal tarsus axis. The tarsi are provided with four groups of tarsal mechanosensilla, comprising hair and bristle sensilla, campaniform sensilla, and scolopidia. The tarsus wall is supported by an epidermis, which forms three different types of glands pouring their secretion via different exit paths onto the outer cuticle. The organization and ultrastructure of each of these glands is described. Only one (unicellular) gland is directly associated with the ventral tenent setae and is thus considered to form the main part of the adhesive secretion. The beetles appear to release the tarsal secretion through mediation of the tenent setae, which contains a lipid and a proteinaceous fraction. I propose that the secretion is discharged to the outside via a system of very fine pore canals in the wall of the setal shaft. Gas chromatography and infrared spectroscopy revealed that the lipid fraction of the secretion is a mixture of unsaturated fatty acid glycerides and aliphatic hydrocarbons whose spectra are similar to those of extractions of the superficial lipid coating of the body surface.

Fine structure of the intersegmental membrane glands of the sixth abdominal sternum of female Nomia melanderi (Hymenoptera, Apoidea)

The fine structure of the intersegmental glands of the sixth abdominal sternum in 1-week old females of Nomia melanderi is presented. The plasma membrane of the secretory cell is unfolded in many places and is covered by a basement membrane. The microvillous surface is invaginated to form a rather long sinuous cavity. The endoplasm is almost entirely filled by secretory granules. Many secretory granules are located close to the inner surface of the invaginated plasma membrane. The invagination contains a porous ductule, apparently of cuticulin origin, that is connected directly with the inner layer of the transport duct of the duct-forming cell. This type of arrangement allows the direct flow of the secretory substance to the outside in a continuous way. The cylindrical duct-forming cell, besides having typical cell organelles, contains a cuticular transport duct. This duct is composed of a thin cuticulin layer surrounded by a rather thick epicuticular one. The results suggest that the secretory cell has two secretory cycles. The first occurs while the gland is differentiating (at the pupal stage) and is involved in secretion of the cuticulin that forms the porous ductule. The second cycle, which starts by the beginning of nesting, is involved in the secretion of a substance that is carried to the outside via the transport duct of the duct-forming cell.