Organogen.sis of the Reproductive System of Helisoma duryi eudiacus (Pilsbry) (Pulmonata, Gastropoda), with Notes on Breeding Habits U~eIM~ Department of Zoology Master of Science ABSTRACT The development of the reproductive system of the frvShwater pulmonate, Helisoma duryi eudiscus (Pilsbry), was studied by means of seriaI sections. Development yas traced from embryos to mature speci­ mens. Chronological and histologic&l changes in the reproductive organs yere studied. The tyO priaordia which gave ris. to the entire reproductive tract yere clarified. Br.eding habits such as mode of hatching, type of fertilization, quantity of eggs laid, effects of o~gen and temperature on hatching and the resist­ &Dca of egg membranes to chemicals were additional aspects dealt Yith in this stuay. • Organogenesis of the Reproductive System of He1isoma duryi eudiscus (Pi1sbry) (Pu1monata, Gastropoda), with Notes on Breeding Habits by Mabe1 Mai, B.Sc. A thesis submitted to the Facu1ty of Graduate Studies and Research in partial fu1fi11ment of the requirements for t.he degree of Master of Science. Department of Zoology YcGil1 University, Montreal Ju1y 1969 .' l' r'::\. Mabe1 Mai 19'70 ;1 .i ACKNOWLE1XHŒNTS The wri~er Yi.h•• to thank Dr. Carol M. Lalli for her close supervision over the major part of ~hi. study and for her patience and assistance in rea4ing and correcting every detail of the manuscrip~. A special note of thanks is due to Dr. Tyrell Smith for suggesting the ~opic and supervising part of the experiment. Ur. Ronald Chalk has been Most helptul in providing ~echnical assistance in the preparation of the photomicrographs. The writer Tould like to thank many other staff members of the Departmen~ of Zoology for ~heir advice and assist­ ance in supplying various equipmen~s and materials. This study Tas supported partially by a Scholarship from the Na~ional Research Council, and by & research assistan~ship under Dr. Tyrell Smi~h, Account No. 283-53 of the Na~ional Research Council. ii TABLE OF CONTENTS Page LIST OF FIGURES ------.--------._.-------- iii LIST OP PLATES iv INTRODUCTION --------.--------------- 1 MATERIALS AND METHODS ----------------------- 7 GENERAL -------------.------------- 7 000 ANOG ENESIS ---_._-- -----_ .. 8 BREEDING HABITS .lN]) HATCHING 9 RESULTS -----------------------------_. ------ 13 ORGANOGENESIS ------- -------- 14 BREEDING HABITS AND HATCHING ------- 27 DISCUSSION --------------------------------- 31 ORGANOGENESIS ---------------- 31 BREEDING HABITS AND HATCHING ---- 35 SUMMARY ----------- --------- 39 LITERATURE CITED ----------------------------- 41 APPENDICES 1. FIGURES ------------------------- 47 II. PLATES 52 iii LIST OP PIGURES Figure Page 1. Helisoma àuryi eudiscus, juvenile; shoYing the scheme used in taking maximum shell diameter.-- 48 2. Genital system of adult R. duryj eudiscus ----- 50 3. An egg capsule of R. duryi eudiscua.-------- 51. iv LIST OP PLATES Plate Page 1. Cross section of preputial primordium of Helisoma dUEYi eudiscus at 12 days alter hatching --- . ---- 53 2. Cross section of cord of cel1s migrating from male tract of H. duryi eudiscus at 19 days after hatching - 53 3. Cross section of posterior digestive gland of li. durvi eudiscus at 19 days after hatching, showing the aggregation of germ cells 54 4. Oblique section of preputial complex of ~. duryi eudiscus at 26 days after hatching 54 5. Longitudinal section of anterior female tract of H. duryi eudiscus at 26 days after hatching- 55 6. Longitudinal section of an ovotestis acinus to show hermapnroditic duct of li. durri eudiscus at 26 days alter hatch~g 55 7. Cross section of vagina and seminal receptacle duct of li. duryi eudiscus at 3.5 mm stage 56 8. Oblique section of female gonopore area of ff. duryi eudiscus at 3.5 mm stage, showing gonopore plug 56 e 9. Cross section of uterus and prostate gland of v li. duryi eudiscus at 4 mm stage -- ----------- 57 10. Longitudinal section of preputium of g. duryi eudiscus at 4.5 mm stage, shoYing preputial organ duct ------------------------------- 57 Il. Cross section of prostate gland of g. duryi eudiscus at 4.5 mm stage ---------------- 58 12. Cross sections of hermaphroditic duct of g. duryi eudiscu! at 4.5 mm stage; a) 4 sections ll!l17erior to junction b); b) junction of hermaph- roditic duct; c) 4 sections posterior to b) 58 13. Longitudinal section of hermaphroditic duct of H.duryi eudiscus ·at 4.5 mm .stage --------- 59 14. Cross section of preputial organ of g. duryi eudiscus at 6.0 mm stage ------------------- 59 15. Oblique section of penis of li. duryi eudiscus at 6.0 mm stage ---------------------------- 60 16. Oblique section of oviduct and sperm duct of g. dUrYi eudiscus at 6.0 mm stage ------------ 60 17. Cross section of vagina and seminal receptacle duct of g. dUEri eudiscus at 6.0 mm stage ---- 61 18. Longitudinal section of reproductive tract of H. duryi eudiscus at 6.0 mm stage,------- 61 19. Longitudinal section of the oviduct at the level of the carrefour of g. duryi eudiscus vi. at 6.0 mm stage -------------------------.------------ 62 20. LongitudinaL section of seminal vesicle of R. duryi eudiscus at 7.0 mm stage -- 62 1 INTRODUCTION There have been few thorough studies of the development of the basommatophoran reproductive system. Here, Helisoma du~i eudiscus (Pilsbry) has been chosen for this particular field of research. Helisoma is usually classified as one of the subgenera of Planorbis, of the family Planorbidae a family of freshyater snails. Hyman (1967) recently has reviewed the taxonomy of this group. Helisoma is characterized by its discoi­ dal or planispiral shell with the apex flattened and depressed below the body whorl. The animal is sinistral and has an overall red colour due to the presence of red blood. The genital system ~f common freshwater gas­ tropods has been the subject of much research. Boyever, most investigators limited their york to certain organs, mainly the penial complex and the ovotestis, rather than the.entire system. Büchner (1891) compared the penis of members of the genera Planorbarius, Segmentina, Planorbis, Anisus, Bathyomphalus and Gyraulus. Baker studied the systematics of Helisoma species in Wisconsin (1928) and the large planorbid snails of Europe and America (lQ31), based on the preputial complex and radu­ lae •. He, as well. as most workers, emphasized the signi~i- 2 canee of the penial complex in taxonomie studies. The "penia! gland" reported by Baker Yas later re­ investigated by Abdel-Malek (1952), who determined its function in mating as a "hold-fast organ" and suggested that it should be named as such. The hi5tology and development of th. ovo­ testis of Vallonia pulchella Müll. yere studied by Whitney (1941). Hickman (1931) 1rOrked on the same organ in Succinea ovali. Say, but he yas concerned primarily Yith spermiogenesis. Watson (1919) worked on the affinities of Pyramidula, Patulastra, Acanthinu1a and Val10nia s~ci.s, using the genital system as one of the bases for comparison. The anato~ of the entire ad*Jt geni­ tal tract of Indop1anorbis exustus (Desh.) Yas investi­ gated by Rao (1923) and brief1y by Baker (1945). Crabb (1927) and Holm (1946) studied Lymnaea stagna1is appressa Say and attempted to correlate anatomy and tunction of the reproductive organs. Baker (1928, 1945) deàlt Yiih the reproductive systems of gastropods systematiea11Y. Morton (1955a) studied the evolution of the E1lobiidae, using their genital tract as one of the bases of refer­ ence. He also studied the functiona1 morpho10gy of the reproductive systems of the British El10biidae (1955b). 3 Dunc~ (1960) compared the reproductive systems ot Physa, Lymnaea, Planorbarius and Ancylus, and con­ cluded from similarity ot the reproductive tracts that the tamily Planorbidae yas ev01ved trom Physidae. The gross morphology of the &dult genital system of Helisoma trivolvis (Say) yas studied by Abdel-Malek (1954). In 1854, Hogg made the tirst observations of the develmpment of Lymnaea stagna1is, but he did not mention the development of the reproductive tract. H01mes (1900) studied the early development of Planorbis, from cleavage up to gastrulation. Fraser (1946) dealt with the embryology of the reproduc~ive ~ract of Lymnaea stagnalis appress~. Maturation of the reproductive system of Arion ~ Linnaeus yas treated by Smith (1966), and that of Agriolimax re~iculatus (MÜller) by Runham and Laryea (1968). The mode of hatching of Most pulmonates has aroused the interest ot Many research yorkers, and the presence of an en~e to partially dissolve the inner egg membrane at the time of hatching has been a question open to dispute. Ankel (1937) investigated this in Nucella lapillus (L.) (prosobr~ch) and tound that a larval en~e yas involved (in Davis, 1961). Noland. 4 and Carriker (1946) .tudied the breeding habits of Lymnaea stagnaIi, appressa; their york included copu­ lation, fertilization, oviposition and hatching. Bondesen (1950) made a comparative morphological­ biological .analysis of the egg capsules of freshyater pulmonates an~ recorded the mechanism of hatching in many cases. Davis (1961) studied the emergence of AmQicola limosa Say (prosobranch). D'Asaro (1965) mentioned the dissolution of the apertural plug on egg capsules, probably through the production of en­ zymes, at the hatching of Strombus gigas (prosobranch) veligers. The same author (1966) reported similar observations for Thais haemastoma floridana (prosobranch). ----------~ -----~~ Davis (1967) studied the emergence of veliger larvae from eggs laid by 6erithium algicola Adams (prosohranch) and by four.opisthobranchs: Phidiana. lyncaeus Bergh, Haminea antillarum d'Orbigny, Bertti.elinia caribbea Edmunds and Bursatella pleii Rang. In each case, he found that the egg membranes yere softened before the animaIs crawied O"At, and he concluded :t;hat this softening yas caused by the action of "an enzyme or enzymes;.' '.' Bayne (1966) studied the biochemical composi­ tion of the layers of the egg of Agriolimax reticulatus by means vf thin-layer chromatography, gel-filtration 5 and e1ectrophoresis, and 1ater (1968) emp10yed histo­ chemica1 techniques to study the biochemica1 components of the egg capsules of six pu1monates, one opistho­ branch and one prosobranch.