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< Leonid I. Frantsevich >


Leonid Frantsevich, Stanislav Gorb, Vladimir Radchenko, Dmytro Gladun, Alexey Polilov, Lyubov Cherney, Vassily Browdy, Maxim Kovalev. 2015. Lehr’s fields of campaniform sensilla in beetles (Coleoptera): functional morphology. II. Wing reduction and the sensory field. Arthropod Structure & Development 44, 1-9

Abstract

Loss of the flight ability and wing reduction has been reported for many taxa of Coleoptera. If elytra are closed, their roots are clenched between the tergum and the pleuron, forces applied to the elytra can not be transmitted to the field of CFS situated on the root. That is why it is plausible to assume that the field becomes redundant in non-flying beetles. We examined the relationships between the hind wing reduction and characters of this mechanosensory field in beetles of six families. We measured the size of the elytron, that of the hind wing and counted the number of CFS. Mesopterous non-flying beetles retain one half to one third of CFS present in macropterous species of the same body size. Further reduction of the sensory field in brachypterous species is obvious, but sensilla are still present in insects with strongly reduced wings, as long as their elytra are separable and mesothoracic axillaries are present.


Elytron, wings or wing rudiments (top panel) and Lehr’s fields on the elytra (bottom panel, SEM) in Calosoma and Carabus of comparable body and elytral size: (a) Calosoma sycophanta, (c) Carabus granulatus, (d) Car. arvensis, (e) Car. cancellatus, (f) Car. hungaricus, (g) Car. coriaceus. Scale bars 10 mm (top panel), 50 µm (bottom panel).


Elytra, wings or wing rudiments and elytral Lehr’s fields in three diving beetles species formerly included in one genus Agabus s.l. (Dytiscidae). Top row: elytra and wings, scale bar 5 mm; bottom row: Lehr’s fields, TLM, scale bar 50 µm. (A) flying macropterous Gaurodytes bipustulatus (40 CFS), (B) non-flying mesopterous Eriglenus undulatus (19 CFS), (C) brachypterous G. bifarius (11 CFS).


Elytra, wings and elytral Lehr’s fields in macro-, meso- and brachypterous leaf beetles of the genus Chrysolina. (A) Ch. gypsophylae, 47 CFS; (B) Ch. herbacea, 51 CFS + 3 hairs; (C) Ch. polita, 36 CFS; (D) Ch. coerulea, 32 CFS + 1 hair; (E) Ch. olivacea, 7 CFS + 2 hairs. Scale bars 5 mm for macrophotographs, 50 µm for TLM microphotographs.


Complete loss of CFS coincides with the existence of the permanent sutural lock.


Temporal and permanent sutural locks in non-flying beetles: cross-sections of sutural ridges. (a) Plug and socket split pair in macropterous Calosoma inquisitor; (b) split ridges in brachypterous Carabus cancellatus; (c) split ridges in brachypterous Liparus glabrirostris; (d) plug and socket permanent pair in wingless Blaps lethifera; (e) bulbous permanent plug in macropterous Carabus granulatus; (f) same in wingless Timarcha tenebricosa; (g) same in wingless Lethrus apterus.


However, some beetles with permanently locked elytra still retain few CFS.

A very special case of an extreme wing modification in feather-wing beetles is considered. No sensilla were revealed either on the root of the elytron or on the basal segment of such fringed wings in flying ptiliid species.


Fore and hind wings in a miniature beetle Primorskiella anodonta (Ptiliidae). (A) elytron; (B) trunk with folded pennate wings; (C-F) elytral root in various aspects: dorsal face (C), ventral face (D), medial face (E), lateral face (F). No pits or slits were revealed on a smooth surface of the elytral root. Scale bars 100 µm (A, B), 5 µm (C-E), 5 µm (F).

 

Series of papers:

1. Lehr’s fields of campaniform sensilla in beetles:

- General part and allometry

- Wing reduction and the sensory field

- Modification of elytral mobility


 

     

I. I. Schmalhausen Institute of Zoology, 2004-2018