Studio sulla diversità anatomica della spermateca nei Coleotteri

Abstract

ANATOMICAL DIVERSITY OF THE SPERMATHECA STUDIED IN COLEOPTERA

Out of 144 figured species of Coleoptera, 5 patterns of this organ were detected throughout; they separate from each other by presence/absence of the three fundamental parts: receptacle, duct and gland. The most common pattern (55%) includes every part; whereas the rare pattern of Lacon punctatus includes the gland only. Observed in fresh preparations, spermatheca parts were recognized by following some criteria. (I) Receptacle does usually contain a dense mass of sperm; it was recognised in the parthenogenetic species, Ptinella mekura (Ptiliidae), by examining the amphygonic species of the same family. (II) A study of comparative anatomy allowed to recognized the receptacle of some Scolytidae, Curculionidae and Staphylinidae, where females are used to store sperm also into the adjacent gland. (III) Usually, duct doesn’t contain sperm; sometimes, it contains a low number of the latter if its connection to the receptacle is restricted in any way. (IV) Spermathecal gland, according to Berlese’s definition, is an anatomically separate part and usually includes an efferent duct and a large reservoir or a net of canalicles, both lined by hypertrophic epithelium. (V) Anatomical comparison with species of the same families allowed to recognize the spermathecal gland in two intriguing instances: (a) when gland is engaged to store sperm together with the adjacent receptacle; (b) when it is lone to represent spermatheca.

Iconography reports on further details: (Figs. 6-7) receptacle as single part of the spermateca; (Fig. 9) receptacle internal protuberances; (Fig. 11) septate receptacles; (Fig. 14) inflatable receptacles; (Figs. 15-17) receptacles branched or subdivided; (Figs. 18-19) hypertrophic condition of the receptacle epithelium; (Figs. 20-21) extended muscular sheath; (Figs. 22-23) mechanical support for unsclerotized receptacles; (Figs. 24- 27) receptacle shape arrangements to support the compressor muscle; (Figs. 28-29) mechanical receptacle peculiarities; (Fig. 30) duct-lacking spermatheca; (Figs. 31-32) enormously long ducts; (Fig. 34) enlarged duct; (Figs. 35-36) heavy sclerotized duct cuticle; (Figs. 38-39) duct pumping devices even related with inflatable receptacles; (Fig. 41) sclerotized gland reservoir; (Figs. 42-43) gland pumping/valvular device; (Fig. 45) exceedingly large gland; (Fig. 46) gland reservoir overcoming the receptacle volume; (Fig. 47) gland exit at the duct or at genital chamber.

Key words: terminology, fundamental patterns, anatomical peculiarities.

Si espongono i risultati di uno studio basato sull’esame di preparati a fresco. Le tre parti tipiche della spermateca dei Coleotteri sono state riconosciute tenendo conto di una serie di criteri, in parte predeterminati e in parte emersi nel corso del medesimo studio. In rapporto alla presenza/assenza di “ricettacolo”, “dotto” e “ghiandola spermofila” sono stati individuati 5 modelli di spermateca, dei quali si annota la ricorrenza nelle 144 specie esaminate.

Lo studio evidenzia alcune condizioni anatomiche eccezionali, tra cui: (a) una spermateca rappresentata dal solo ricettacolo; (b) una ghiandola spermofila impegnata a conservare una rilevante quantità di sperma; (c) varie forme di dispositivi pompanti del dotto.

Parole chiave: terminologia, condizioni fondamentali, particolarità anatomiche.