Acta Zoologica Academiae Scientiarum Hungaricae

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ACTA TOOLOGICA ACADEMIAE SCIENTIARUM HUNGARICAE

AN INTERNATIONAL JOURNAL OFANIMAL TAXONOMY AND ECOLOGYActa Mologica Academiae Scientiarum Hungaricae is publis hed quarterly DomFebruary l 994 sother issues in May, August and November) by the Hungarian Natural History Museum and the Biological Section of the Hungarian Academyos Sciences with the financiat support of the Hungari an Academy of Sciences.

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EDITORIAL

cinge of editora The past two years have been Spent by revitati Zing our journat, Acta Mologica Academiae Scientiarum Hungaricae. The responsibility of publis hing the journal on bellais of the Hungari an Academy of Sciences was taken o Ver hythe Hungarian Natural History Museum frona the publishing hou se of the acade-my. Akademiat Kiado. The editorial board was considerably expanded by an internationat panet os editorial ad visors, whose advice and work as a referee aremuch appreciated.

A number of changes in editorial poticy, content and format have taken place OVer the past these two years. The internationat character of the journat hasal ways been our main concerta. In Volume 40 and di one-third of the authorshipcomes Dom ouisi de Hungary, whicli cloes not seem bad for the first phase of the way to beco ming a truly international journat. The former Editor-in-Chies, i Salo P P. resigned Dorn his appo iniment in December, l995. hecati se the burden os a massive international project seditorialwork on the Manual os Palaearctic Diptera) and other commit ments made it difficult for him to maintain the levet os editorial activi ty on the journal in dispensabie for the quali ty required. The Biology Section of the Hungari an Academy of Sciences accepted his resignation and delegated me the task of the Editor- in Chies. The Hungari an members of the editorial board suggested that one more editor would hel p to spread the workload, and they nominated Dr Andmias Demeter as assistant editor. The Biology Section approved this appo iniment as

I reassure the subscribers and readers of Actia goologica hungarica that theainas and the scope of the journal have not changed hecati se of the change in edi- tors hip. However, I have to confess that we are Struggling with a major problem. In order to maintain a quali ty of paperS. we must rely on re Viewers' opinion. Actia

Mologica Academiae Scientiarum Hungaricae publishes papers in the fields ofanimal taxon Omy and SystematicS, ZOOgeography, animal ecology, communi tyecology. population genetics, population biology, biodiversi ty studies and nature con SerVation problems. In the past two years have been able to provide a fairly rapid publication forum for the accepted papers. The journat is indexed in Current ContentS.

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Acta Mologica Academiae Scientiarum Hungaricae 42 I); ρρ. 3-I0. I996

AN INTERESTING REPRODUCTION TYPE IN ENCHYTRAEI DS OLIGO CHAETA)

Dmari merit of Systemiatic Mology and Mology, EotvoS Lor in f Universi H I088 Bud est, Pus in v. I, Hungcto The reproduction biology os a recently described enchytrae id species, Enchytraeus duilichiwas investigated. This species is able to reproduce both sexu atly and asexu atly by fragmentation. Data about the cocoon deposition. the incubation period, the growth of juveniles. thematuration, the occurrence of fragmentation. and the number, siZe, and growth of fragments were determinecl. When populations of E. duilichi Occur in low densities fragmentationresulis. Fragmentation enliances the chance of the species to successsul ly coloniZe new habitatS. whereas Sexuat reproductiora maintains genetic diversity with in the population. Key words: Enchytraeidae, Sexual and asexuat reproduction. fragmentation

Reproduction by fragmentation in enchytrae lds is a rare phenomenon. The species of the genera Cognettia and Buchholetia are well known for their fragmentation capabilities CHRISTENSEN l 959. NIELSEN and CHRISTENSEN l 959). Untii now only five species of the genus EnchytraeuS including E. duilichi, have been mund to reproduce this way. Among these Species, E. j orienSiS NAKAMUR A. t 993. the adult form of whicli is unknown, re produces Only by fragmentation NAM AMUR A l 993). and E. fragmentoSus BELI , t 959 reaches sexuat maturi tyon ly under particular breed ing conditions VENA et a l. l 969). The species E. Digeminus NIELSEN and CHRISTENSEN. l 963 and E. variatus BOUGUEN EC and GIANI, l98J are capable of hoth sexual and asexuat reproduction. EnchytraeuS ludichi DOZSA-FARMAS l 995 a recently described species, was mund in gardenso it originating Dom Iran. We observed that this species is also capable os fragmentation in laboratory cultureS. The objective of study was to obtain more delailed information on the re-

productive biology of E. duilichi.

MATERIAL AND METHODS

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AN INTERESTING REPRODUCTION TYPE IN ENCHYTRAEIDS

In the study of sexuat reproduction, the number of deposited cocoons, thedimensions of the cocoons. the number of eggS per cocoon, the incubation peri-od, and the growth rate of the juveniles were determinecl. In the case of fragmentation the number os fragments per animal the number of SegmentS per fragment the fige of fragmenis, and the growth rate os fragments were studied.

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Fig. S. Crowth of the tength of juveniles at 22 24 'C

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Higher temperatures accelerate regeneration. The growth rate os fragments kept at 29 30 'C was more than twice that os fragments kept at 22 24 'C theyreached the sanae si Ze at three and se vela days, respective ly. By this time the headis complete ly regeneraled, and the animais are capable of Decling. Aster this timeon ly the posterior part develops. The regeneration of the head in E. Digeminus

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Fig. 8. Developing fragment

Fragmentation en hances the chanceS Of the species to Successsul ly coloni Zene w habitatS, WhereaS Sexuat reproduction maintains genetic diversi ty with in thepopulation. The factors elici ting maturation and cocoon deposition can be very different. During mOSt of the year Species of the genera Cognettia and Buchlistria re-

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REFERENCES