Schmalhausen Institute of Zoology

Kiev, Ukraine

Schmalhausen Institute of Zoology

Kiev, Ukraine
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Frantsevich L.,Schmalhausen Institute of Zoology
Journal of Insect Physiology | Year: 2012

Transient movements of the elytra (opening and closing) were filmed in beetles tethered from below. A total of 39 specimens of 18 species representing 11 families were examined. Bright markers glued to the elytra were traced frame by frame. Body-fixed 3D traces of apical and shoulder markers were reconstructed. Shapes of traces reflected different steps of elytral movement and different types of flight. Flat circular arcs were fitted to scattered traces using the least square method. The rotation axis of the apical marker was always directed at the contralateral side. The trace of the shoulder marker was, as a rule, non-parallel to the apical trace. Usually, the shoulder marker on the costal edge of the elytron uniformly supinated in the course of adduction of the apical marker. Traces of opening and closing coincided, hence the double rotation of the elytron had one degree of freedom. The elytron to body articulation in beetles is, presumably, a spherical mechanism with two separate but linked drives for a broad swing during opening (closing). © 2011 Elsevier Ltd.

Movements of the elytra and axillary sclerites were video recorded in tethered flying beetles and in manipulated mounts. Mesothoracic axillary plates are homologues of those in the metathorax. Two anterior axillaries (Ax1, Ax2) fuse together; they are hinged to the third axillary plate (Ax3). In turn, Ax3 is hinged with the elytron. During takeoff, a beetle abducts and highly elevates its elytra (1), then droops the elytra in a flatly spread position (2); closing is adduction in a horizontal plane (3). These steps have been simulated: (1) by pressing down the anterior horn; (2) occurred spontaneously after release of pressing; (3) the elytron closed flatly either by manual turn of the elytron or by manual elevation of the prothorax. Anterior axillaries rotated forward and down during (1), returned during (2) and remained immobile during closing. Ax3 is folded between the closed elytron and Ax1. +. Ax2; it unfolds during opening. Two hinges of Ax3 form a Z-configuration and provide a linked drive for complicated rotation of the elytron. Opening was impaired in vivo if tergal leg protractor and depressor were disabled, closing did not suffer. Closing was prevented by excision in the hind edge of the pronotum, not harmful for opening. Role of direct and indirect muscles in transient elytral movements is discussed. © 2012 Elsevier Ltd.

Frantsevich L.,Schmalhausen Institute of Zoology
Zoology | Year: 2012

Voluntary movements of the prothorax and the elytra in tethered flying beetles and manually induced movements of these parts in fresh dead beetles were recorded in 30 species representing 14 families. Participation of prothoracic elevation in the closing of the elytra was demonstrated in three ways. (i) The elevation was always simultaneous with elytral closing, in contrast to depression and elytral opening; a rare exception occurred in Lucanus cervus, whose elytra sometimes started to close before the cessation of wing strokes and the elevation of the prothorax. (ii) The manipulated elevation always induced closing of the spread elytra; the mechanical interaction between the hind edge of the pronotum and the roots of the elytra is a universal mechanism of closing the elytra in beetles. (iii) The prevention of pronoto-elytral contact in live beetles by the excision of the hind edge of the pronotum in front of the root prevented elytral closing after normal flight. Exceptions to this rule included some beetles that were able to close their elytra after such an excision: tiger beetles and diving beetles (seldomly) and rose chafers (always). This ability in Adephaga may be explained by attachments of the muscle actuating the 4th axillary plate, which differ from the attachments in Polyphaga. Cetoniinae open their elytra only by a small amount. It is proposed that their small direct adductors in combination with the elasticity of the sclerites are enough to achieve elytral closing without additional help from the prothorax. © 2012 Elsevier GmbH.

Frantsevich L.,Schmalhausen Institute of Zoology
Journal of Bionic Engineering | Year: 2011

We recorded transient movements, i.e. opening and closing, of beetle elytra. The beetles were tethered from below and filmed under a skew mirror; two markers were glued on each elytron at the apex and at the base. Body-fixed 3D traces of the apical and basal markers were reconstructed. The trace of the basal marker was, as a rule, non-parallel to the apical trace. The costal edge of the elytron uniformly supinated in the course of adduction of the apical marker. We found two essential attributes of double rotation: (1) the elytron to body articulation is approximately a spherical mechanism; (2) transient opening and closing possess single degree of freedom. The double rotation was modeled with two mechanisms: (1) a flexagon model of the Haas and Wootton's type simulated the elytral movement relative to the movement of one facet of the flexagon; (2) a screw and nut model provided traces as two sectors of a helical thread, one sector was phase shifted with respect to other one. Screw guideways in a spherical mechanism give rise to discrepancies. Exact solution for a spherical mechanism with two guideways was proposed. The modeling revealed the attribute (3): the elytron is actuated by two linked but differently directed drives. Experimental investigations on the elytron to body articulation may be oriented at search of those mechanisms. © 2011 Jilin University.

Frantsevich L.,Schmalhausen Institute of Zoology
Journal of Experimental Biology | Year: 2010

Actuation of the closing of the elytra was previously ascribed to intrinsic muscles in the mesothorax. We investigated closing (1) by loading or arrest of some thoracic segments in a tethered flying beetle, (2) by animation, i.e. passive motion of preparations of the thorax simulating the action of some muscle, and (3) by excision of some parts of sclerites or cuts across certain muscles. We found out that depression of the prothorax, necessary to unlock the elytra, precedes their opening but elevation of the prothorax is synchronous with the closing. The closing is retarded if the elevation is retarded by loading; if the elevating prothorax is clamped, then the closing is also arrested or hindered; animation of the elevation of the prothorax in the dead animal is enough for the closing of the previously spread elytra; the closing is prevented if a piece at the hind edge of the pronotum, positioned in front of the root of an elytron, is excised. This excision also prevents closing in the in vivo experiments. Mechanical interaction between the elytron and the prothorax is limited to the contact point between the posterior edge of the pronotum and the lateral apophysis of the root. Thus, the elevation of the prothorax is the indirect and main mechanism of the closing in Melolontha. ©2010. Published by The Company of Biologists Ltd.

Simutnik S.A.,Schmalhausen Institute of Zoology
Russian Entomological Journal | Year: 2015

Sulia glaesaria gen. et sp.n. is described and illustrated from Danish amber collection of the Zoological Museum of University of Copenhagen. A brief comparative morphological analysis of the new genus is made. As all previously described Encyrtidae of the Late Eocene amber fauna, the new genus is characterized by long veins of the forewing. © RUSSIAN ENTOMOLOGICAL JOURNAL, 2015.

Frantsevich L.,Schmalhausen Institute of Zoology
Arthropod Structure and Development | Year: 2016

Legs in a fly pupa are tightly folded in Z-configuration: the femur points forward. The fly emerges from the pupa with all legs stretched backwards. How does the fly turn long femora inside the tight puparium? Flies were captured during emergence at various moments of progress out of the puparium and at once fixed in ethanol, postfixed in Bouin's solution. Specimens were ranged by the grade of progressive extrication and maturation. Legs were excised, their configurations photographed. Legs are anchored to the VIII. abdominal segment of the puparium with the pupal sheath. Some podomers were arched or buckled yet in pharate adults. At the initial moment of extrication, new buckles appeared in femora, they split femora into 2-subpodomers. Instead of turning the whole femur, the fly dragged through the puparium a chain of short subpodomers linked together with transient hinges. Hinges emerged in unsclerotized areas of the tubular podomer, close to sclerotized areas (juvenile sclerites). During extrication, legs were stretched passively. This process lasted for 1-min, initial phase - few seconds. Residual distortions were left in hind legs of free juvenile adults. Mechanics of buckling and straightening is discussed from the viewpoint of strength of materials. © 2016 Elsevier Ltd.

Gumovsky A.,Schmalhausen Institute of Zoology
Zootaxa | Year: 2014

The first Afrotropical species of Trisecodes Delvare & LaSalle, 2000, T. africanum Gumovsky, sp. n., is described from localities in Uganda, Guinea and Cameroon. The new species differs from the type species of the genus, T. agromyzae, which was described from the Neotropical region in Belize, mostly by having longitudinally strigate sculpture on the me-sosoma dorsally and by the fore wing being somewhat darkened in its basal three-fifths. A possible Gondwanan origin of the genus is postulated. Copyright © 2014 Magnolia Press.

Klymenko S.I.,Schmalhausen Institute of Zoology
Vestnik Zoologii | Year: 2010

Based on the analysis of morphological characteristics of related species of the genus Eurytoma, several groups of cryptic species poorly distinguishing by external morphology, but clearly confined to certain hosts are shown to have morphological differences of male genitalia that are highly species-specific and can be useful for identification of cryptic species of the genus Eurytoma (E. rosae Nees, E. strigifrons Thomson, and E. jaceae Mayr species complexes).

Dzeverin I.,Schmalhausen Institute of Zoology | Ghazali M.,Schmalhausen Institute of Zoology
Evolutionary Biology | Year: 2010

Phenotypic evolutionary rates were measured for 27 craniometric characters in 12 extant OTUs from the bat genus Myotis (Chiroptera, Vespertilionidae). Squared Mahalanobis distance was used as a multivariate measure for amount of divergence, and squared Mahalanobis distance weighted by time was used as a measure for the rate of divergence. Estimates for the rates of divergence were found to be consistent with random walk hypothesis. Thus, the divergence in Myotis could be guided by random drift and mutations. The high dispersion in rate estimates suggests also a possible input of randomly fluctuating selection. The highest rates were recorded for divergence between M. myotis-M. blythii species group and the other OTUs. Rates of divergence between the subspecies of M. blythii occur to be lesser than rates of divergence between the earlier diverged species, their divergence could probably be slowed down by stabilizing selection. Size-adjusted data appeared to be lesser then the initial data, and it can be concluded that both size and shape were involved in divergence of Myotis species. The skeletal characters in bats are known to be extremely conservative during long-term evolution, however, the possibility for random walk at short time interval implies that bat evolution is constrained rather ecologically and biomechanically than genetically or developmentally. © 2010 Springer Science+Business Media, LLC.

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