•yژRگ´ڈ،‚ج”ژژmٹwˆتک

•yژRگ´ڈ،‚ج”ژژmٹwˆتک_•¶

ک_•¶”•\‚µ‚ؤ‚¢‚é•”•ھ‚ج‚فŒِ•\‚µ‚ؤ‚¢‚ـ‚·پB

Contents پi–عژںپj

Abstracts ..............................................................1

Aknowledgements ........................................................4

Contents ...............................................................6

1. General Introduction ................................................9

2. Description of Study Site in the Ogasawara Islands Outline of OgasawaraIslands ..................................11

پ@پ@Distribution of Achatina fulica in Ogasawara Islands..........13

پ@پ@Description of study sites....................................13

3. Growth Pattern and Protandry of Achatina fulica

پ@پ@Introduction ..................................................18

پ@پ@Materials and methods.........................................19

پ@پ@پ@پ@Dissection of reproductive system

پ@پ@پ@پ@Growth pattern trace by mark-recapture experiment

پ@پ@پ@پ@Comparison of genital system between adults and subadults

پ@پ@Results.......................................................21

پ@پ@Morphology and function of genital system.............21

پ@پ@پ@پ@پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–

پ@پ@Relationship between shell growth and peristome thickness........24

پ@پ@Comparison of genital system between subadults and adults...26

پ@پ@Discussion....................................................27

پ@پ@پ@پ@Self-fertilization

پ@پ@پ@پ@Maturation of A.fulica

پ@پ@پ@پ@Protandry

پ@پ@پ@پ@Reproductive cycle of land snail

4. Oviposition and Characteristics of Egg Clutches in Achatina fulica

پ@پ@Introduction..................................................41

پ@پ@Materials and Methods.........................................42

پ@پ@پ@پ@Observation of oviposition and hatching

پ@پ@پ@پ@Dissection of pregrant snails

پ@پ@Results.......................................................43

پ@پ@پ@پ@Oviposition and hatching of A.fulica in laboratory

پ@پ@پ@پ@Observation clutch size and egg volume

پ@پ@Discussion....................................................46

پ@پ@پ@پ@Variation of clutch size and egg volume in A.fulica

پ@پ@پ@پ@Ecology of egg laying in pulmonate land snails

5. Activity patterns of Achatina fulica

پ@پ@Introduction..................................................55

پ@پ@Materials and methods.........................................56

پ@پ@پ@پ@Study site

پ@پ@پ@پ@Radio-transmitters

پ@پ@پ@پ@Radio-taggeing for determination of snail age

پ@پ@پ@پ@Detection of radio-tagged animals

پ@پ@پ@پ@Activity analysis by means actogram

پ@پ@Results.......................................................59

پ@پ@پ@پ@Shell growth in radio-tagged snails

پ@پ@پ@پ@Activity pattern of the snail

پ@پ@پ@پ@Long distance movement traced by radio-tracking

پ@پ@Discussion....................................................62

6. Daily movements of Achatina fulica around Resting Sites

پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–

7. Homing Behabior of Achatina fulica

پ@پ@Introduction..................................................84

پ@پ@Materials and methods.........................................85

پ@پ@پ@پ@Study site

پ@پ@پ@پ@Observations on locomotive activity at night

پ@پ@پ@پ@Snail movements examined by removal and transplanting

پ@پ@Results.......................................................86

پ@پ@پ@پ@Movement pattern at night

پ@پ@پ@پ@Mark-recapture experiment

پ@پ@پ@پ@Transplantation of snails

پ@Discussion....................................................88

پ@پ@پ@پ@Homing behavior of A.fulica

پ@پ@پ@پ@Adaptive significance of homing in Pulmonates

پ@پ@پ@پ@Orientation mechanisms

8. Mating behavior in Achatina fulica

پ@پ@Introduction..................................................97

پ@پ@Materials and Methods.........................................97

پ@پ@پ@پ@Observation site

پ@پ@پ@پ@Hourly change in number of copulating pairs

پ@پ@پ@پ@Observations on courtship behavior and duration of copulation

پ@پ@پ@پ@Repeating ability of copulation in an individual

پ@پ@پ@پ@Characteristics of mates chosen in copulation

پ@پ@Results.......................................................99

پ@پ@پ@پ@Mating activity

پ@پ@پ@پ@Courtship behavior

پ@پ@پ@پ@Duration of copulation

پ@پ@پ@پ@Repeating ability of copulation in an individual

پ@پ@Discussion...................................................103

9.پ@پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–

10.پ@پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–

11.پ@پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–

12.پ@پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–

13.پ@پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–

14. General Discussion ...............................................216

پ@پ@پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–پ–

Summary ..............................................................224

Referance ............................................................227

Japanese Abstracts ...................................................247

Plates ...............................................................248

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