The land snail Oxychilus (Drouetia) atlanticus is endemic to São Miguel (Azores). In this species, the reproductive system, especiailly the glandular organs, changes in size and shape during the reproductive cycle. As maturation-diagnostic organs, the seminal vesicle and the
albumen gland have complementary interpretations. While the former is appropriate to establish the phase of the pre-copulatory and copulatory periods the latter appears a more accurate way to define pre-egg-laying and egg-laying periods. Concerning the effects of photoperiod and temperature on both organs, it seems that while the former triggers the physiological phenomena related to reproduction, inducing the seminal vesicle and the albumen gland to mature, the latter acts mainly as a regulatory factor for these organs, delimiting the distinct phases of reproduction

Cunha, Regina Tristão da

Rodrigues, Armindo

Sousa, H.

Repositório da Universidade dos Açores

INFLUENCE OF TEMPERATURE AND PHOTOPERIOD ON THE MATURATION OF THE SEMINAL VESICLE AND ALBUMEN GLAND IN Oxychilus (Drouetia) atlanticus (GASTROPODA: PULMONATA) TRISTAO DA CUNHA, R., A. S. RODRIGUES & H. SOUSA TRJSTAQ DA CUNHA. R., A.S. RODRIGUES & H. SOUSA. 2001. The influence of temperature and photoperiod on the maturation of the seminal vesicle and albumen g !and in 0,rychilus (Droueiin) otlar~ricus (Gastropods: Pulmonata). Arquipdago. Life and Marine Sciences. Supplement 2 (Past B): 67-70. Ponta Delgada. ISSN 0873-4704, The land snail Oxychilus (Drorreriu) a~fanticus is endemic to SLo Miguel (Azores). In this spccies, the reproduct~vc system, especiaiIy h e  glandular organs, changes In size and shape during thc reproductive cyclc. As maturat~on-diagnostic organs, the seminal vesicle and Ihe albumen gland have complementary interpretat~ons. Whtle the former is appropriate to estnbl~sh the phase of rhe pre-copulatory and copulatory periods the latter appears a more accurate way to define prc-egglaying and egg-lay~ng periods. Concerning the effects oi' photoperiod and temperature on both organs. i t  seems that while the Former triggers the physiological phenomena rela~eci to reptuduction, inducing the seminal vesicle and the alhumen gland to mature. the latter acts mainly as a regulatory factor for these organs, delimiting thc distinct phases uf rcprodwction. R. Trisrdo da C14nha (P-mail: rcrtnha@notes.rrac.pt), A. Rndripes & [I. Snusa, Universidad~ dos A r o r ~ . ~ ,  Departamcnto de Binlqyia, Rua da Mee dde Deus .W, PT - 9.W I - 801 Ponra Uel~cfda, Portrigal. INTRODUCTION O ~ c h i l f i s  (Drouetia) ntlantictrs is a land snail endemic to Sb Miguel (Azores). In this species, as in Stylornmatophora in gencral. the reproductive system changes in size and shape during the reproductive cycle. These changes, which are better seen in glandular organs such as the seminal vesicle and thc spermoviduct, may be used to diagnose maturation ( ~ O D R I G I J ~  1995). Although stylommatophorans are simulraneous hermaphrodites, some species reveal a form of prokndry (BAUR 1994) in which the male function reaches maturity before that of the female (SOKOLOVE & MCCROYE 1978). In Oxycl~ilus atlanticus, gonadal maturation is characterized by an earlier development of spermatogenesis followed later by vitellogenesis of the oocytes. subsequently show~ng spermatozoa and oocytes side by side in the same acinus (RODRIGUES 1995). The albumen gland, which i~ a Fcmalc organ, is a compound alveolar gland (TOMPA 1984), very similar in Stylnmmatophora in general (NOYCE 1973) and i t  is the lasl part of the reproductive system to develop, changing in size and colour in aduEt snaiFs (R1r;nY 1963; RUNHAM & LARYEA 1968; ELS 1978; TOMPA 1984). Reproductive development is controlled by endocrine mechanisms, induced by environmental parameters, mainly photoperiod and temperature (TOMPA 1984; BAKER 1988 j. According to BECK (1968) photoperind promotes the synchrony of internal functions that regulate biological systems, as well as affecting every organism in its geographical distribution, seasonal bioIogy, growing, shape, metabolic rates and behaviour. In Order Stylornrnatophora. PARIVAR (1978) found that temperature affects the gonadal development and the relative proportion of male and female gametes, although it affects spermatogenesis more than oogenesis (SMITH 1966), and it is the key factor to initiate spermatogenesis and egg laying (TOMPA 1984). Life cycles and life spans are also affected by changes in both temperature and photoperiod (UMINSKl19T3; TOMPA 1984; SACCHI 1990). The aim of this study is i) to test the validity of the albumen gland as a new diagnostic organ of sexual maturity, using the seminal vesicle as the reference organ (RODRIGUES 1995), and ii) to relate the general development of both organs with photopcriod and temperature along the reproductive cycle o f  the species. SAMPLING SITE The climate of he island is of the humid Atlantic type, characterised by prolonged rainy pcritds in winter and spring, mild temperature (mean 17.5"C). very h ~ g h  air relative humidity (>go%) and sail moisture, even during the summer months (BETTENCOURT 1977). Phorophase in the Azores, located between 36"SS'N - 39'45'N and 24"45 W - 3 1 " I7'W, ranges from around 10 hours in January, to l4h30' in June (Fig. IA), decreasing at the same rate after July (BECK 1968). The sampling site, Abelheira, lies about 4 km north-east of Ponta Delgada, 130 m above sea level. Data on temperature from the meteorological station Afonso de Chaves, was used to characterize Abelheira during the sampling period. MATERIALS AND METHODS Sampling of Oqchilus ~tlntiticus at Alxlheira started in November 1993 and lasted until December 1995. For the study of the seminal vesicle and the albumen gland, 10 individuals with the highest shell diameter were selected From each monthly sample, since this parameter is considered to be the most reliable estimator of age (CHARRLER & DACUzAN 1978). I n  order to examine the correlation between abiotic parameters and the seminal vesicle and albumcn gland, data were organized in four sampling periods, winter 1993-spring 1994. summer-autumn 1994, wintcr 1944-spring 1995, and summer-autumn 1995. The seminal vesicle was classified according to one of the three degrees of development established by RODRIGUES ( 1995). based on external morphology: 1) narrow and straight; 2) of intermediate thickness and slightly folded (coiled); 3) thick and heavily coiled. The albumen gland was measured with EDUSKAN-3.1. a program developed by BELLLDO (1993)- Monthly values of the albumen gland were divided into four size classes: 1) small [<5.0x10~ p21; 2) of intermediate size [5.0xld- 10.0~10~ p 2 ~ ;  3) large [10.01x 10"20.0x 1 6  pZ], and 4) very large [>20.01 xlo5 p". These size classes were considered to reflect the sequence of physiological changes exhibited by the albumen gland during growing. RESULTS In the individuals of Oxychilus afianriclls studied, the maximum shell diameter (SD) ranged from 5- 6 mm in January-February to 8-8.5 rnm in  Iare autumn and early winter. 'The pattern of growing was very similar from year to year, indicating an annual life cycle with a maximum longevity of 18 months {TRISTAO DA CUNHA 1995). According to the degree of maturity shown by the seminal vesicle, individuals were immalure or undergoing maturation betwecn January and May and mature between June and November- December (Fig. 1B). Measurements of the area (size) of the albumen gland (Fig. 1B) show that the organ was not developed between January and June, slowly began to increase betwcen June and October, and reached the highest area in November-December. PHOTOPHASE VS. SEMINAL VESICLE AND ALBUMEN GLAND There is a strong correlation (r2d.942, P=0.01, N=760) between photophase and the degree o f  maturity exhibited by the seminal vesicle. The organ is fully developed in June, when photophase is at its maximum (14h30'), and remains mature until November-Dcccmber, despite the decrease of photophase (Fig. 1A and B). Fig. 1. A) Photophase (hr) (1) for the Azores latitude and Temperature rC) ( )  a1 Abetheira. between Novcmhr 1993 and Dcccrnbcr 1995; B) Degrees of rnalurity of the Semmal Vesiclc (average 2 sd) I-) and size (p2 )  of  the Albumen Ghnd (average k sd) ( )of 0. nllerlticus, between November 1993 and December 1995, ;it Abelheira. Photophase and albumen gland exhibit a similar general pattern but the highest values of the former anticipate those of the latter by 6 months. The correlation between them is low (rZ=0.523, P=0.10, N=260). In June when phetophase is at i ts maximum, the albumen gland starts to develop, reaching the highest size in December, despite the decrease in photophase (Fig. 1A and B). TEMPERATURE VS. SEMINAL VESICLE AND ALBUMEN GLAND There is a strang correlation between temperature and seminal vesicIe (?=0.95, P=0.01, N=260). The organ i s  immature when temperature rs lower than 16" C and fully developed when temperature is higher than 18" C (Fig. 1A and B). The correlation between ternperamre and aIburnen gland development i s  high (r2=0.847 P=0.01, N=260). Maximum values of temperamre exhibit a delay of two months relative to the highest measured area of the albumen gland (Fig. 1A and El. DISCUSSION i )  IS THE ALBUMEN GLAND A NEW DIAGNOSTE ORGAN OF SEXUAL M A T U R ~ ?  From data on shell diameter, seminal vesicle maturity and albumen gland size, it is possible to establish that the reproductive system of Oxychilus attanficus develops gradually as the animal grows and it appears to be fully developed when it reaches around 7.5 mrn diameter, between June and November. However, the pattern of  maturation in both organs is distinct. The sernina! vesicle is mature between June and November, which is in accordance with RODRTGUES ( 1995). with specimens immature the rest of the year. The albumen gland starts to develop by June but the rapid enlargement only occurs in October - November, signaling final maturatian and vitellogenesis of the oocytes in the gcmad. A similar general pattern was also observed by RIGBY (1963), in 0, helvelicus, and by SOKQI,OVE & MCCRQNE (1478), in Lirruu: 111n.l-irnus. As maturation-diagnostic organs of sexual maturity, the albumen gland and seminal vesicle have complementary interpretations. The seminal vesicle may be used to establish the phase of the pre-copulatory and copulatory periods, the albumen gland seems more accurate to define pre-egg-laying and and egg-laying periods. i i )  EFFECTS OF PHOTOPHASE ANT) TEMPERATURE OK THE SEMINAL YESICIE AND ALBUMEN GLAND According to the data presented, photophase correlates with and probably triggers the physiological phenomena related to reproductian, inducing the seminal vesicle and the aIbumen gland to increase in size, while temperature acts mainly as a regulazory Factor for thcse organs, making a clear demarcation between the distinct phases of reproduction. Further work wirl be needed to test these hypotheses among. ACKNOWLEDGEMENTS The authors thank Professor Frias Martins for helpful discussions and cornents. The present work was supported by the prqject PRAXIS/2J2.1/BEA/169/94 - Biodiversidade. REFERENCES BAUR. B. 1994. Parental care in terrestrial gastropods. Erperientia 50: 5-14. BECK. S.Q. 1968. Illsect Phaioperiodism. Academic Press, New York. 288 pp. BELLIDO, E.J.S.  1993. Desarrolo de ittt sistrma de ancjlisis pIanirnArico auromatitado con torrra de dodos en un lector de barrido digital: bases le6ricas y desarrolla ~~cnologico, Memaria presentada para oprar a1 grado de licenc~ado en Ciencias Biol6gicas, Universidad del Pais Vasco, Facultad de Ciencias, Bilbao, 73 pp. CIEARRIER. M & J. DAGUZAN. 1978. 6tude dc la croissance de ['escargot "Petit Gris" Helir ospersa Mhller f Mollusque Gasteropodc Pulmont). Halioris 9(l): 15-[8.  Em. W.1. 1978. Histochemical studies on the maturation of the genital system of the slug Dcmceras laec.~,  (Pulmonata. Limacidac) with spcc~al refcrcnce to the identiiicatinn of rnucasubstances secretcd by the genital tract. At~nale van die U~rir!~rsireir va!l Sirllrrtbosch A2, 3 (1): i-116. NQYCE. A.C. 1973. The morphotogy and histology af  the genital system of Tlteba pisuna (Milllcr) (Pulrnona~a: Helicidae). AnnaIe VQn die I I ~ i v ~ r ~ i t ~ i f  van Ste~let~hosck A 48 (3): 1- 140, PARIVAR. K. 1978. A histolog~cal survey or gonadal development in Ariotl nler- L. (Mollusca. Pulmonata). Jolwnal of Moll~rscan Srrrdies .44: 250- 264. RIGRY, J.E. F 963. Allrnentary and reproductive systems of O.rychilus cel!arrus (Miiller) (Stylornmarophara). Procwdings of the Zoological Soricfy of I ~ n d o n  141 : 3 1 1-359. R o u ~ r c u a .  A.S. 1995. Ciclo Reprdutor em 0.ychilus (Droueria) a![artticlc.s (Morelet & Drouet). Trabalho de sintese elaborado no hmbi~o das Provas de Apt~dHo Pedag6glca e Capacidade Cientifica. Un~versidde dns Aqores, Ponta Qelgada. 85 pp RUNHAM, N.H. & A.A. LARYFA 1968. Stud~es on the rnaturatron of the reprod~rctive system of Agriolirnax retic~h!us (Pulmonata: Limacidae). Malncologiu 7 (1) :  93-108. SACCHI, C.F. 1990. Observations sur le cycle b~otlque de Theba pixana IMiiIler) (Gatropda. Pulmonata) en Europe et cn Australie. Rollerrno Sucieth Malacolog ica I~nlinna 2 6  73-82 S M ~ T I ~ ,  B.J. 1966. Maturatton of the reproductive tmci or Arion aler (Pulrnonata: krionidae). n%lacologia 4 (2): 325-349. SOKOLOVE, P.G. & E.J. MCCRONE. 1978. Reproductive rnaturalion in \he slug, Litnm muxin~us, and she effects of artiliclal photoperiod. Jolrrital of Compomriiv Physiology 125: 3 17-325 TOMPA. A.S. 1984. h d  Snails (Stylommatophora). Pp. 47- 140 in: K. M. WLBER {Eds). The Mollrlsca. Vol. 7. Academic Press, London. 486 pp. TRISTAO DA CUNHA, R. 1995. L~fc cycle o i  Oqrhilus (Dmrreria) nrlaniiclts (Morelet & Droutt, 1857) (Pulmonta: Zonitidae). Absrrocfs of the Twcfrh Intrrnatio~~uI Malamlogicaf Congress. Vigo, Spain: 280. UMlnsK!. T. 1975. Life cycles in some Vitrinidm (Maliusca, Gastmpoda) from Poland. AnnaIes zoalo~ici Warszawo 33: 17-33, 

Influence of temperature and photoperiod on the maturation of the seminal vesicle and albumen gland in Oxychilus (Drouetia) atlanticus (Gastropoda: Pulmonata)

Influence of temperature and photoperiod on the maturation of the seminal vesicle and albumen gland in Oxychilus (Drouetia) atlanticus (Gastropoda: Pulmonata)

Abstract

Similar works

Full text

Available Versions

Repositório da Universidade dos Açores

Repository of the University of the Azores