The reproductive system of gastropods slugs and snails varies greatly from one group to another within this very large and diverse taxonomic class of animals. Their reproductive strategies also vary greatly, see Mating of gastropods. In many marine gastropods there are separate sexes male and female ; most terrestrial gastropods however are hermaphrodites.
Courtship is a part of the behaviour of mating 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 dartsthe throwing of which have been identified as Snails reproducing asexually form of sexual selection.
Gastropods are defined as snails and slugs, belonging to a larger group called Molluscs. They can be separated into three categories: Hermaphroditic gastropods possess both the egg and sperm gametes which gives Snails reproducing asexually the opportunity to self-fertilize. The reproductive system of marine gastropods such as those from class Opisthobranchia and order Archaeogastropoda from the class Prosobranchiais a continuous cycle of alternating male and female reproductive role prevalence.
Immediately after spawning in late summer, the predominance of the female reproductive functions are terminated and gametogenesis initiates immediately, with the start of the predominance of the male reproductive role. Gametes remain in the gonads throughout the winter and early spring. The female reproductive role takes over again in May with fertilization of the gametes to form zygotes.
The cycle comes full circle in late summer once again, "Snails reproducing asexually" spawning. In many taxonomic groups of marine gastropods, there are separate sexes i.
In some of the
Snails reproducing asexually gastropod clades the great majority of species have separate sexes. This is true in most of the PatellogastropodaVetigastropodaCocculiniformiaNeritimorphaand Caenogastropoda.
Within the clade Littorinimorpha however, the superfamily Calyptraeoidea are sequential hermaphrodites.
Protandry means that the individuals first become male, and then later on become female. See for example the genus Crepidula. Within the main clade Heterobranchiathe informal group Opisthobranchia are simultaneous hermaphrodites they have both sets of reproductive organs within one individual at the same time. There are also a few marine pulmonatesand these are also hermaphroditic, for example, see the air-breathing sea slug family Onchidiidaeand the family of air-breathing marine "limpets" Siphonariidae.
Although most land snails are pulmonates and are hermaphrodites, in contrast, all of the land-dwelling prosobranch snails are dioecious in other words, they have separate sexes.
This includes the snails in the families PomatiidaeAciculidaeCyclophoridaeand others. These land snails have operculawhich helps identify them as "winkles gone ashore", in Snails reproducing asexually words, snails within the clade Littorinimorpha and the informal group Architaenioglossa.
Members of the snail family Pulmonatawhich includes carboniferous land sails and some freshwater snails of the order Basommatophoraare protandrous hermaphroditesmeaning they are born male and later in life become female. In this family of snails, the male phase ends in December, followed by an egg maturation phase, and ends with ovipositionthe act of laying eggs during May of the following year.
Phylogenetic evidence for this is present based on the overall condition of the gonads especially in the degree of development of the genital ducts. Pulmonate land gastropods are simultaneous hermaphroditic and their reproductive system is complex. It is all completely internal, except for the active protrusion eversion of the penis 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 Snails reproducing asexually in this organ. Together with the bursa tract and bursa copulatrix these form Snails reproducing asexually 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 of reproductive system in stylommatophorans is common feature. The structure of the reproductive system is strictly hermaphroditic. From the gonadsa hermaphrodite duct, a duct which is designed to transport both sperm and eggs, leads to a Snails reproducing asexually of the reproductive tract where the duct splits into a strictly male and strictly female portion. The female portion includes a fertilization pouch and posterior and anterior mucus glands, which open up into a pallial cavity which leads to a small muscular vagina.
The male portion of the reproductive tract includes both a short posterior vas deferens and a longer anterior vas deferens. posterior vas deferens is followed by the prostate, and the anterior vas deferens flows through the haemocoelean enlarged "Snails reproducing asexually" filled with blood, of the head and opens into a muscular penis which is engulfed in a small portion of skin called the prepuce sac.
Species in the freshwater gastropod family such as the Caenogastropoda from the class Prosobranchiaare largely self-fertilizing; however after many generations of selfing, a physiological barrier halts sperm generation in that organism, and only allows for the introduction of foreign sperm. Gametes form in the ovotestiesan organ which produces both ova and sperm, and pass down into the hermaphroditic duct to the albumen gland, the junction of where the common duct splits to either vas deferens or oviductwhere they Snails reproducing asexually stored until they are needed for either mating or self-fertilization.
It is believed that this junction acts as a regulatory mechanism via contracting muscles, to help direct sperm or eggs into the correct ducts. The sperm passes into the male duct, or vas deferens,
Snails reproducing asexually is receives secretory additions in the form of mucus from the prostate.
After getting modified, the sperm passes into the penis. During mating season, the glandular cells in the penis sheath and prepuce swell to facilitate eversion of the penis. The sperm gets pushed through the penis, where they are introduced into the tail end of its copulatory partner. Within the partner snail, after fertilization from the foreign sperm, the eggs pass into the albumen gland where they are coated in mucus which forms the egg capsule.
Eggs are released immediately before oviposition. Unlike in land gastropod species where fertilization occurs in fertilization pockets, fertilization in freshwater species happens at the lower end of the hermaphroditic duct, near the junction. Sperm is deposited into the bursa copulatrix which opens up into the vagina.
The ova then enter the "Snails reproducing asexually" gland to get a nutrient dense mucus coating which serves to form the egg capsule. The prostate is found in the mantle tubule and penis are both connected to the gonoduct; which are connected to the testis produce sperm.
During sex, the sperm travels along the mantle tube in which Snails reproducing asexually fluid fills the mantle tube and exits the body via the penis and enters the females gonopore. Females have a gonopore that is connected to a seminal receptacle. The gonopore acts as an opening through which eggs are deposited. The opening leads into the mantle tubule, in which eggs flow from the oviduct and ovary. The mantle tubule produces three things, yolk ; carries most of the nutrients needed to develop a healthy offspring, egg capsule formation, and sperm reception and storage; where fertilization occurs.
After fertilization, eggs travel to the albumin glands to fill the yolk with protein, and lastly, the egg travels through the capsule glands, which coat the egg in a protective jelly.
Hermaphrodites have both male and female reproductive parts.
The male and female system act as separate until the egg and sperm are ready to fuse together. The fusion of egg and sperm takes place in the uterus of the female system. Hermaphrodites also have a hermaphroditic duct, which helps change the sex of the gastropod during certain times of the year. This article incorporates CC -BY From Wikipedia, the free encyclopedia. Canadian Journal of Zoology. BMC Evolutionary Biology,5: Population and Conservation genetics.
The biology of terrestrial molluscs. Proceedings of the Zoological Society of London. Clausilium Love dart Operculum Pearl Radula. Circulatory system of gastropods Crop Ctenidium Digestive system of gastropods Diverticula Excretory system of gastropods Gastric shield Hancock's organ Hepatopancreas Hypobranchial gland Nephridium Nervous system of gastropods Nidamental gland Odontophore Oesophageal pouch Osphradium Reproductive system of gastropods Respiratory system of gastropods Sensory organs of gastropods.
Sexual selection Sexual reproduction evolution reproductive system Courtship display sexual ornamentation handicap principle sexy son hypothesis Fisherian runaway Mating systems mate choice mating call mating plug lek mating Copulation Cloacal kiss Sexual intercourse pseudocopulation Fertilisation internal external sperm competition traumatic insemination penile spines Modes monogamy promiscuity polyandry polygyny polygynandry semelparity and iteroparity opportunistic hermaphroditism cuckoldry seasonal synchrony Reproductive synchrony Sexual dimorphism anisogamy oogamy Bateman's principle bimaturism cannibalism coercion "Snails reproducing asexually" conflict interlocus intralocus Interspecies breeding Non-reproductive behavior Fisher's principle.
Arthropods crab spider scorpion beetle insect butterfly Cephalopods octopus Cnidaria sea anemone jellyfish coral Echinoderms Gastropods apophallation love dart Snails reproducing asexually Worms earthworm penis fencing. Sexual selection frogs Frog reproduction Salamanders. Sexual selection in Snails reproducing asexually reptiles lizards snakes side-blotched lizard Crocodilians Tuatara. Sexual selection Breeding behaviour golden eagle seabirds Homosexual behavior.
Sexual selection rut Lordosis behavior Homosexual behavior Canid African wild dog coyote dingo domestic dog gray wolf red fox Dolphin Elephant European badger Felidae lion tiger cheetah domestic cat Fossa Hippopotamus spotted hyena Marsupial kangaroo Pinnipeds walrus Primates human bonobo gorilla olive baboon mandrill ringtailed lemur sexual swelling Raccoon Rodent Short-beaked echidna. Retrieved from " https: Gastropod anatomy Animal reproductive system.
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Wikimedia Commons has media related to Reproductive system of Gastropoda. I've had my snail for 2 months, and only now are little ones showing up. Do they reproduce asexually, or do they store eggs for a long time?.
Why not reproduce asexually? Many organisms do, though most of Snails reproducing asexually are single-celled bacteria and other simple life forms.
Still, some. Asexual mud snails grow faster and reproduce earlier than sexual ones. "This is making the role of sex even harder to explain," says Maurine.