Reproductive system of gastropods
Encyclopedia
Reproductive system
The reproductive system or genital system is a system of organs within an organism which work together for the purpose of reproduction. Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system. Unlike most organ systems, the sexes...
of gastropods (slug
Slug
Slug is a common name that is normally applied to any gastropod mollusc that lacks a shell, has a very reduced shell, or has a small internal shell...
s and snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
s) varies greatly from one group to another within this very large and diverse taxonomic class of animals. Their reproductive strategies also vary greatly.
In many marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
gastropods there are separate sexes (male and female); most terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
gastropods however are hermaphrodite
Hermaphrodite
In biology, a hermaphrodite is an organism that has reproductive organs normally associated with both male and female sexes.Many taxonomic groups of animals do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which both...
s.
Courtship is a part of mating behavior in some gastropods.
In some families of pulmonate land snails, one unusual feature of the reproductive system and reproductive behavior is the creation and utilization of love dart
Love dart
A love dart is a hard, long, sharp, calcareous or chitinous dart which some hermaphroditic land snails and slugs create. Love darts are made in sexually mature animals only, and are used as part of the sequence of events during courtship, before actual mating takes place...
s.
Separate sexes
In many taxonomic groups of marine gastropods, there are separate sexes (i.e. they are dioeciousDioecious
Dioecy is the property of a group of biological organisms that have males and females, but not members that have organs of both sexes at the same time. I.e., those whose individual members can usually produce only one type of gamete; each individual organism is thus distinctly female or male...
).
The great majority of species in some of the main gastropod clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
s have separate sexes. This is true in most of the Patellogastropoda
Patellogastropoda
Patellogastropoda, common name true limpets and historically called Docoglossa, is a major phylogenetic group of marine gastropods, seen either as a clade or as a taxonomic order.-Taxonomy:Patellogastropoda was proposed by David R...
, Vetigastropoda
Vetigastropoda
Vetigastropoda is a major taxonomic group of sea snails, marine gastropod mollusks that form a very ancient lineage. Taxonomically Vetigastropoda are sometimes treated as an order although they are a clade in Bouchet and Rocroi, 2005....
, Cocculiniformia, Neritimorpha
Neritimorpha
Neritimorpha is a taxonomic grouping, an unranked clade of snails, gastropod mollusks. This grouping includes land snails, sea snails, some deepwater limpets, and also freshwater snails...
, and Caenogastropoda
Caenogastropoda
Caenogastropoda is a taxonomic clade of a large diverse group of mostly marine gastropods.Caenogastropoda contains a majority of the families of shelled marine molluscs including such families as the periwinkles, cowries, wentletraps, moon snails, and cone snails.About 60% of all living gastropods...
.
Protandrous sequential hermaphrodites
Littorinimorpha
Littorinimorpha is a large clade of gastropods within Hypsogastropoda consisting primarily of marine species, but also aquatic and terrestrial species as well....
however, the superfamily Calyptraeoidea are protandrous sequential hermaphrodites. Protandry means that the individuals first become male, and then later on become female. See for example the genus Crepidula
Crepidula
Crepidula, common name the "slipper limpets" or "slipper shells", is a genus of sea snails, marine gastropod mollusks in the family Calyptraeidae, the slipper snails and cup-and-saucer snails....
.
Simultaneous hermaphrodites
Heterobranchia
Heterobranchia, the heterobranchs or Euthyneura, is a taxonomic clade of snails and slugs, which includes species from the sea, the land and freshwater; marine, aquatic and terrestrial gastropod mollusks....
, the informal group Opisthobranchia
Opisthobranchia
Opisthobranchs are a large and diverse group of specialized complex marine gastropods previously united under Opisthobranchia within the Heterobranchia, but no longer considered to represent a monophyletic grouping...
are simultaneous hermaphrodites (they have both sets of reproductive organs within one individual at the same time).
There are also a few marine pulmonates
Pulmonata
The Pulmonata, or "pulmonates", are an informal group of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills...
, and these are also hermaphroditic, for example, see the air-breathing sea slug family Onchidiidae
Onchidiidae
Onchidiidae are a family of small, air-breathing sea slugs. They are shell-less marine pulmonate gastropod molluscs. Onchidiidae is the only family within the superfamily Onchidioidea....
, and the family of air-breathing marine "limpets" Siphonariidae
Siphonariidae
Siphonariidae is a taxonomic family of small to medium-sized air-breathing sea snails, marine and brackish water pulmonate gastropod molluscs. These snails are sometimes known as "false limpets" because of the shape of the shell, but they are not at all closely related to true limpets...
.
Separate sexes
Although most land snails are pulmonates and are hermaphrodites, in contrast, all of the land-dwelling prosobranch snails are dioeciousDioecious
Dioecy is the property of a group of biological organisms that have males and females, but not members that have organs of both sexes at the same time. I.e., those whose individual members can usually produce only one type of gamete; each individual organism is thus distinctly female or male...
(in other words, they have separate sexes). This includes the snails in the families Pomatiidae
Pomatiidae
The family Pomatiidae is a taxonomic family of small operculate land snails, terrestrial gastropod mollusks that can be found over the warmer parts of the Old World. In the older literature, this family is designated as Pomatiasidae....
, Aciculidae
Aciculidae
The Aciculidae are a family of minute land snails which have opercula. In other words, Aciculidae are terrestrial operculate gastropods....
, Cyclophoridae
Cyclophoridae
Cyclophoridae is a taxonomic family of small to large tropical land snails with an operculum, terrestrial gastropod mollusks in the informal group Architaenioglossa belonging to the clade Caenogastropoda .- Taxonomy :This family consists of the following subfamilies according to the taxonomy of...
, and others. These land snails have opercula
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
, which helps identify them as "winkles gone ashore", in other words, snails within the clade Littorinimorpha
Littorinimorpha
Littorinimorpha is a large clade of gastropods within Hypsogastropoda consisting primarily of marine species, but also aquatic and terrestrial species as well....
and the informal group Architaenioglossa
Architaenioglossa
Architaenioglossa is a taxonomic group of snails which have gills and often an operculum. They are primarily land and freshwater gastropod mollusks within the clade Caenogastropoda....
.
Simultaneous hermaphrodites
Penis
The penis is a biological feature of male animals including both vertebrates and invertebrates...
for copulation. The outer opening of the reproductive system is called the "genital pore"; it is positioned on the right hand side, very close to the head of the animal. This opening is virtually invisible however, unless it is actively in use.
The love-dart (if available) is produced and stored in the stylophore (often called dart sac) and shot by a forceful eversion of this organ. The mucus glands produce the mucus that is deposited on the dart before shooting. The penis is intromitted to transfer the spermatophore. The sperm container is formed in the epiphallus, while the spermatophore's tail is formed by the flagellum. When a bursa tract diverticulum is present, the spermatophore is received in this organ. Together with the bursa tract and bursa copulatrix these form the spermatophore-receiving organ, which digest sperm and spermatophores. Sperm swim out via the tail of the spermatophore to enter the female tract and reach the sperm storage organ (spermathecae) within the fertilization pouch-spermathecal complex.
Variability (polymorphism
Polymorphism (biology)
Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species — in other words, the occurrence of more than one form or morph...
) of reproductive system in stylommatophora
Stylommatophora
Stylommatophora is a taxon of air-breathing land snails and slugs, terrestrial pulmonate gastropod molluscs. This taxon is currently considered to be a clade. It was previously regarded as an infraorder...
ns is common feature. Such variability may include:
- euphallics = male copulatory organs are developed as usual
- hemiphallics = male copulatory organs are reduced
- aphallics = there is no male copulatory organs developed
- in Heterostoma paupercula is presence or absence of epiphallus and flagellum
- in Arion hortensisArion hortensisArion hortensis, common name the "garden slug", "small striped slug" or "black field slug" is a species of small air-breathing land slug, a terrestrial pulmonate gastropod mollusk in the family Arionidae, the roundback slugs....
is usually bipartite oviduct but there sometime can appear tripartite free oviduct - in Fruticicola fruticumFruticicola fruticumFruticicola fruticum is a species of medium-sized, air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Bradybaenidae.-Shell description:The shell of this species is globular with a deep umbilicus...
is various number of mucous gland lobes in auxiliary copulatory organs
Examples of reproductive system of various land snails:
Genital structures
Genital structures in StylommatophoraStylommatophora
Stylommatophora is a taxon of air-breathing land snails and slugs, terrestrial pulmonate gastropod molluscs. This taxon is currently considered to be a clade. It was previously regarded as an infraorder...
include (English name and Latin/Greek name is after the hyphen):
- albumen gland - glandula albuginea
- atriumAtriumAtrium may refer to:*Atrium , a large open space within a building usually with a glass roof*Atrium , microscopic air sacs in lungs*Atrium , an anatomical structure of the heart* Atrium of the ventricular system of the brain...
- atrium / vestibulum - bursa copulatrix - bursa copulatrix
- dart sac - bursa teloris
- diverticulumDiverticulumA diverticulum is medical or biological term for an outpouching of a hollow structure in the body. Depending upon which layers of the structure are involved, they are described as being either true or false....
- diverticulum - epiphallar caecum - epiphallus caecum
- epiphallus - epiphallus
- fertilisation pouch - camera fertilis
- flagellumFlagellumA flagellum is a tail-like projection that protrudes from the cell body of certain prokaryotic and eukaryotic cells, and plays the dual role of locomotion and sense organ, being sensitive to chemicals and temperatures outside the cell. There are some notable differences between prokaryotic and...
- flagellum - genital aperture - apertura genitalis
- hermaphroditic duct - ductus hermaphroditicus
- hermaphroditic gland - glandula hermaphroditica, ovotestisOvotestisAn ovotestis is a gonad with both testicular and ovarian aspects. In humans, ovotestes are an anatomical abnormality associated with gonadal dysgenesis.- In gastropods :...
- love dartLove dartA love dart is a hard, long, sharp, calcareous or chitinous dart which some hermaphroditic land snails and slugs create. Love darts are made in sexually mature animals only, and are used as part of the sequence of events during courtship, before actual mating takes place...
- spiculum amoris - mucous glands, digitiform glands - glandulae mucosae
- pedunculus - pedunculus
- penial appendix - appendix
- penial caecum - caecum
- penial papilla - penis papilla
- penial steeth - penis capsula
- penisPenisThe penis is a biological feature of male animals including both vertebrates and invertebrates...
- penis / phallus - retractor muscle of the appendix - musculus retractor appendicis
- retractor muscle of the penis - musculus retractor penis
- retractor muscle of the vagina - musculus retractor vaginae
- spermatophoreSpermatophoreA spermatophore or sperm ampulla is a capsule or mass created by males of various animal species, containing spermatozoa and transferred in entirety to the female's ovipore during copulation...
- spermatophora - spermoviduct - spermoviductus
- prostateProstateThe prostate is a compound tubuloalveolar exocrine gland of the male reproductive system in most mammals....
- pars prostetica = a gland related to male part of the reproductive system - uterusUterusThe uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
- pars uterica - stimulatory organ - appendicula
- vaginaVaginaThe vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...
- vagina - vas deferensVas deferensThe vas deferens , also called ductus deferens, , is part of the male anatomy of many vertebrates; they transport sperm from the epididymis in anticipation of ejaculation....
- vas deferens / ductus deferens