Sperm diversity in scorpions (Scorpiones)

KLANN, A., VIGNOLI, V., PERETTI, A. V., CARRERA. P., MICHALIK, P., TALLARICO, G. & G. ALBERTI

San Pedro, San Pablo, Brasil

Simposio; 17th International Congress of Arachnology. Simposio: “Reproductive Biology of Scorpions”.; 2007

International Society of Arachnology

The present study aims to investigate the ultrastructure of spermiogenesis, spermatozoa and sperm packages in scorpions from a comparative point of view. Several species oE the families Buthidae, Bothriuridae, Scorpionidae, Troglotayosicidae, Euscorpiidae and Iuridae were investigated by means of electron microscopy. In general, scorpion spermatozoa areof the filiform-flagellate type and bear certain characters which differ between families - (1) Shape of acrosomal complex, (2) position of acrosomal complex, (3) presence or absence of acrosomal filament, (4) shape of nuc1eus, (5) axonemal pattem, (6) number of mitochondria, (7) shape of mitochondria, (8) mitochondrial assodated structures (MAS) and (9) shape of sperm packages. OnIy in buthid species, an anteriorly corkscrew shaped nudeus, an acrosomal complex located at the side of the nucleus, a 9x2+2 axonemal pattem and two long mitochondria coiled around the axonema could be observed. AlI the other species investigated show a 9x2+0 axonemal pattem, a long thread-like nucleus and an acrosomal complex located at the tip of the nucleus. The number of mitochondria varies between 3 (Bothriuridae), 5 (Scorpionidae, Iuridae), 4-5 (Troglotayosicidae), 6-8 (Euscorpiidae). The mitochondria possess a structured matrix consisting of small spherical bodies, which can differ between families. Furthermore, in Scorpionidae, Troglotayosicidae, Euscorpiidae and luridae MAS couId be observed. At the end of spermiogenesis the mature sperma tozoa Can either loosely aggregate (Buthidae) or form distinct packages. In Bothriuridae these packages consist of parallel orientated sperm cells, sometimes surrounded by a thin secretion sheath at the anterior part, with curved tips to certain degrees depending on the species. In Scorpionidae and Troglotayosicidae the spermatozoa bend to form oval sperm packages without secretion sheath. Euscorpiidae possess round sperm packages of coiled sperm cells, fully surrounded by a secretion sheath. This structural diversity is discussed conceming theír implications for reproduction and theír potential value Eor phylogenetic studies.