Annelida, Hirudinida (Leeches) Leeches are hermaphrodites with both male and female reproductive structures. Many undergo a brief protandrous stage at which the male tissues (testisacs) mature before the female tissue (ovisacs). What is hermaphrodites are animals that?
Are leeches protandric hermaphrodites?
Leeches are protandric hermaphrodites, with the male reproductive organs, the testes, maturing first and the ovaries later.
What is a hermaphrodite?
A hermaphrodite is an organism with both male and female genitalia. In sexually reproducing organisms, males have organs that produce male gametes, usually sperm. Females have different sexual organs that produce female gametes, usually called eggs.
Do leeches have male and female parts?
As hermaphrodites, leeches have both male and female sex organs. Like the earthworms they also have a clitellum, a region of thickened skin which is only obvious during the reproductive period. Mating involves the intertwining of bodies where each deposits sperm in the others' clitellar area.
Do hermaphrodites pair up with each other to reproduce?
Sometimes the genders pair off equally, one male for one female. Other times, one male or female will breed with a large group of the other gender. Hermaphrodites tend to be solitary animals, although exceptions exist.
Why leech is called hermaphrodite?
All leeches are hermaphrodites, showing either protandry or cosexuality (Davies and Singhal, 1988), with reciprocal cross-fertilization as the general rule.
Why is leech considered a hermaphrodite class 12?
Leeches and tapeworms are hermaphroditic, meaning they have reproductive organs from both sexes in the same individual. Leeches, on the other hand, do not self-fertilize, whereas tapeworms do. Hydra can be hermaphroditic or have distinct sexes. Roundworms are sexually dimorphic, whereas earthworms are hermaphrodites.
Are leeches both sexes?
As hermaphrodites, leeches have both male and female sex organs. Like the earthworms they also have a clitellum, a region of thickened skin which is only obvious during the reproductive period.
What type of reproduction is leeches?
Leeches reproduce in the spring. They are hermaphrodites, and reproduce through reciprocal fertilization, in which both leeches become impregnated at the same time. The mother leech forms a tough, gelatinous cocoon around the egg mass and attaches it to a hard object or buries it in the mud.
Why does a leech have 32 brains?
Leech has 32 brains. A leech's internal structure is segregated into 32 separate segments, and each of these segments has its own brain. Leech is an annelid. They have segments.
What does hermaphrodite mean?
Definition of hermaphroditic : possessing both male and female reproductive organs, structures, or tissue : exhibiting hermaphroditism : of, relating to, or being a hermaphrodite hermaphroditic worms hermaphroditic flowers Most corals are hermaphroditic—they release both male and female gametes.—
Are leeches asexual?
Most species of annelids can reproduce both asexually and sexually. However, leeches can reproduce only sexually. Asexual reproduction may occur by budding or fission.
How do leeches get pregnant?
Reproduction. All leeches are hermaphrodites, meaning each one has both male and female reproductive organs. However, they do reproduce sexually--usually by intertwining their bodies together. One leech's male organ release a spermatophore, or a capsule that encloses sperm, which is then attached to the other leech.
Why earthworm is considered as a hermaphrodite?
Earthworms are hermaphrodites, meaning an individual worm has both male and female reproductive organs. Earthworm mating typically occurs after it has rained and the ground is wet. They emerge from the soil and jut out their anterior end.
How many ovaries does a leech have?
The female reproductive system consists of one pair of ovisacs containing the ovaries, which, although located in front of the testes, may extend some length posteriorly, depending on the animal.
What are the characteristics of leech?
Leeches are segmented worms with suction cups at each end. Their bodies are flattened, much wider than they are thick. They are usually dark colored, often brown or sometimes black or dark green. Some species have no markings, others have spots and stripes.
How hermaphrodite condition is advantageous for the parasitic mode of life?
Hermaphrodites have the great advantage of being capable of reproduction even if they cannot find another member of their species in a host, by self-fertilization. In heteroxenous life cycles a distinction is first made between the final host and intermediate host.
Why earthworm is considered as a hermaphrodite?
Earthworms are hermaphrodites, meaning an individual worm has both male and female reproductive organs. Earthworm mating typically occurs after it has rained and the ground is wet. They emerge from the soil and jut out their anterior end.
Is cockroach a hermaphrodite?
Hermaphrodites are those organisms during which both the sex organs are present. The cockroach, ant, and termite are monosexual.
Do leeches reproduce asexually?
Annelid Reproduction However, leeches can reproduce only sexually. Asexual reproduction may occur by budding or fission. Sexual reproduction varies by species. In some species, the same individual produces both sperm and eggs.
How do leeches get pregnant?
Reproduction. All leeches are hermaphrodites, meaning each one has both male and female reproductive organs. However, they do reproduce sexually--usually by intertwining their bodies together. One leech's male organ release a spermatophore, or a capsule that encloses sperm, which is then attached to the other leech.
Why are leeches used?
Use. Leeches have been used for bloodletting, wound healing, and stimulating blood flow at postsurgical sites. Use in osteoarthritis is being investigated, but there is a lack of clinical information to make recommendations.
What is the purpose of leeches in surgical procedures?
Ischemic tissue. Medicinal leeches are used to stimulate the flow of blood at postoperative surgical sites . 2, 15, 16. After attaching to the site, leeches secrete compounds, especially hirudin, that reduce blood viscosity.
What are the contraindications for leech therapy?
Arterial insufficiency, previous exposure to leeches (risk of allergic reaction), immunosuppression (risk of infection), patient refusal to accept possible subsequent blood transfusions, and unstable medical conditions have been described as contraindications for extensive leech therapy. 9
What is the most common microbial species found in leeches?
The gram-negative Aeromonas hydrophilia is the predominant microbial species found in leeches. 1, 9, 29, 30 Serratia, Klebsiella, and Pseudomonas have also been isolated 10, 31, 32, 33, 34 and patients should receive appropriate prophylactic antibiotic therapy. Older studies suggested possible transmission of HIV and hepatitis, but this is less likely with the use of farmed leeches. 22, 35 Reuse of leeches is not recommended due to concerns of disease transmission. 4
How long does it take for a leech to bleed?
Passive bleeding after detachment can continue up to 72 hours but most commonly continues for about 5 hours.
How many species of leeches are there?
There are more than 700 species of leeches, all of which are carnivorous. 1 The leech is an hermaphrodite, containing both male and female sexual organs, but is not self-fertile.
What are the risks of leeches?
Arterial insufficiency, previous exposure to leeches (risk of allergic reaction), immunosuppression (risk of infection), patient refusal to accept possible subsequent blood transfusions, and unstable medical conditions have been described as contraindications for extensive leech therapy.
What is a leech's shape?
Some leeches are long and worm-like, others pear-shaped and broad. Most can vary considerably in shape both between the elongated and contracted state and between the starved and full condition.
What is Leeches used for?
Medical use of leeches also includes treatment of black eyes, and hirudin is used in the treatment of inflammation of the middle ear. Hirudin is also being developed for experimental use as a systemic anticoagulant, and may prove useful in invitro blood sampling. Leeches in Sydney suburbs.
What is the name of the group of leeches that bite the host?
One group (the jawed leeches or Gnatbobdellida) have jaws armed with teeth with which they bite the host. The blood is prevented from clotting by production of a non-enzymatic secretion called hirudin. The land leech commonly encountered by bushwalkers is included in this group.
How many jaws does a leech have?
Leeches usually have three jaws and make a Y-shaped incision. The Australian land leech has only two jaws and makes a V-shaped incision. Habitat. Most leeches are freshwater animals, but many terrestrial and marine species occur. Land leeches are common on the ground or in low foliage in wet rain forests.
What is the best way to protect against leeches?
The most common enquiry regarding leeches concerns repellents. It is unknown whether a specific preparation is commercially available but there is a plethora of tried and tested, but unproven leech-protection ideas. These include a lather of bath soap smeared on exposed parts and left to dry, applications of eucalyptus oil, tropical strength insect repellent, lemon juice and impenetrable barriers of socks and pantyhose.
Do leeches have sex organs?
Breeding behaviours. As hermaphrodites, leeches have both male and female sex organs.
Do leeches live in the backyard?
The Sydney suburban sprawl is resulting in houses extending into areas such as wet valleys that leeches normally prefer. It is therefore less distance for these leeches to travel in wet weather before they end up in backyards and can get a meal from domestic animals or humans living there. Similarly the domestic animals and humans themselves unwittingly bring many leeches home with them from bush walks, holidays, and other travels. If these leeches are adult they will invariably find a suitable damp spot in the garden to lay their eggs and suddenly you have a colony of leeches in your backyard.
How do leeches reproduce?
Leeches are hermaphrodites with both male and female reproductive structures. Many undergo a brief protandrous stage at which the male tissues (testisacs) mature before the female tissue (ovisacs). Most species reproduce only with another individual and may have more than one mate, but some Glossiphoniids may self fertilize when mates are not available. Many leeches are capable of breeding multiple times (iteroparous) and exhibit saltatory (irregular) growth after reaching reproductive maturity. The typical life cycle of leeches consists of egg (which is deposited inside a cocoon), juvenile, and reproductive hermaphrodite adult. Freshwater leeches typically breed in the spring, lay eggs into a secreted cocoon in the summer, and overwinter in the benthos or on a host. Juveniles of sanguivorous species require a minimum of 3–5 blood meals to reach sexual maturity. The typical life span for leeches is 1–3 years.
Why does hermaphroditism occur at all in freshwater snails?
Why then does hermaphroditism occur at all in freshwater snails? Pulmonates are slow-moving and go through seasonal “bottlenecks” (precipitous declines in density). The chances of finding a mate in such situations are small, providing a selective advantage for monoecy. Pulmonates are dispersed passively as spat trapped in mud on birds’ feet ( Boag, 1986 and references therein), and solitary, monoecious immigrants have an obvious advantage. The cost of inbreeding depression is evidently less than not being able to reproduce at all. Parthenogenesis (being able to reproduce without males) may have a similar adaptive value for caenogastropod snails that are isolated in small headwater streams ( Vail, 1978 ).
How does Fasciola hepatica reproduce?
Fasciola hepatica is a hermaphrodite and auto-fertilization is achievable, although cross-fertilization between two adult flukes is the most common form of sexual reproduction. Fasciola hepatica has two stages of growing in its life cycle: the sexual stage in its adult form and the asexual in the larval or intermediate stages ( Figure 3). The normal habitat of the parasite is biliary ducts and gall bladder of the definite host. In these locations, the mature parasite releases its eggs, which escape the host's body via the feces. The undifferentiated ovum in the egg, after spending 9–15 days in the water, develops into miracidium which hatches out of the egg and searches for a snail intermediate host from the family of Lymnaeidae, including species of the Galba / Fossaria group for F. hepatica and species of Radix for F. gigantica. The life expectancy of miracidium is approximately 8 h, during which time it must find a suitable snail. It then goes through several development stages in the snail (i.e., sporocyst followed by redia), which include considerable asexual multiplication. In the final stage, tailed cercariae, measuring 200–300 μm, emerge from the snail and swim through the water until they locate suitable vegetation on which they encyst, becoming metacercariae.
What is the process of asexual reproduction in Platyhelminthes?
The free-living Platyhelminthes are hermaphrodites, and reproduction can be either sexual or asexual. During sexual reproduction, internal fertilization occurs by auto- or exogamy. The main types of asexual reproduction are paratomy (chain-like transverse fission where individuals are formed before breaking), architomy (division of the organisms in two and each fragment develops the missing organs), fragmentation (several fragments are formed due to muscle contractions and each of them originates a new individual) and parthenogenesis (reproduction without fertilization). Paratomy is usually regarded as the plesiomorphic state, belonging to a complex of ancestral characters of Platyhelminthes (Rieger et al., 1991; Ehlers, 1992). Paratomy is common in Catenulida, but is also present in Acoela, Macrostomida, Proseriata and Tricladida.
What is a hermaphrodite?
A hermaphrodite is an organism with both male and female genitalia. In sexually reproducing organisms, males have organs that produce male gametes, usually sperm. Females have different sexual organs that produce female gametes, usually called eggs. In sexually dimorphic organisms, each organism only has type of reproductive organs, and the population is divided into genders. Sometimes the organisms are divided almost equally. In these cases, individuals must compete for mates. Sometimes the genders pair off equally, one male for one female. Other times, one male or female will breed with a large group of the other gender.
Why do people have hermaphrodites?
In humans, hermaphrodites are caused by a variety of genetic conditions. In one form, a hermaphrodite or intersex person is created when two fertilized eggs fuse together, giving the zygote two X chromosomes and one Y chromosome. Other cases of hermaphrodites are caused by the SRY gene, the gene responsible for testosterone and male genitals, being transferred to the X chromosome during meiosis, resulting in both male and female genitals.
Why are worms considered hermaphrodites?
An added benefit of being a hermaphrodite is that if a worm never finds a mate, it can fertilize its own eggs and reproduce that way. Many hermaphrodites experience this benefit.
Why are hermaphrodites considered solitary?
Being a hermaphrodite is thought to increase the chances of solitary organisms reproducing, because they can both give and receive gametes.
What is the hermaphrodite that lives in your backyard?
A hermaphrodite that can be found in your own backyard is the earthworm. Earthworms spend their days deep beneath the soil, burrowing in random directions and aerating the soil. Two earthworms could be only a short distance apart, and never come into contact.
Is a tunicate a hermaphrodite?
The tunicate is a regular, or simultaneous hermaphrodite. At the same time, the tunicate has both male and female reproductive organs. It can produce both eggs and sperm. In sequential hermaphrodites, only one at a time can be produced. 2.
Is a flower a hermaphrodite?
Flowers. Some plants are hermaphrodites. In their reproductive organs, flowers, there are both male and female reproductive systems. The pollen, or male gamete is released from a stamen. The female part, the stigmata, is a long tube that leads to ovules containing eggs. The pollen must make its way from the stamen to the stigma.
What is a hermaphrodite?
In reproductive biology, a hermaphrodite ( / hɜːrˈmæfrədaɪt /) is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes.
What are some examples of hermaphrodites?
Earthworms are another example of a simultaneous hermaphrodite. Although they possess ovaries and testes, they have a protective mechanism against self-fertilization. Sexual reproduction occurs when two worms meet and exchange gametes, copulating on damp nights during warm seasons. Fertilized eggs are protected by a cocoon, which is buried on or near the surface of the ground.
What is the term for abnormal cases of dioecious animal species?
The term hermaphrodite is commonly used for abnormal cases of dioecious animal species but according to geneticist Michael Majerus this definition should be distinguished from the scientific definition.
What is the opposite of hermaphrodite?
Animal species having different sexes, male and female, are called gonochoric, which is the opposite of hermaphrodite. There are also species where hermaphrodites exist alongside males (called androdioecy) or alongside females (called gynodioecy ), or all three exist in the same species (called trioecy ); these three systems are sometimes called ...
How does K. marmoratus reproduce?
K. marmoratus produces eggs and sperm by meiosis and routinely reproduces by self-fertilization. Each individual hermaphrodite normally fertilizes itself when an egg and sperm produced by an internal organ unite inside the fish's body.
What is the reproductive system of gastropods?
Reproductive system of gastropods: Pulmonate land snails and land slugs are perhaps the best-known kind of simultaneous hermaphrodite, and are the most widespread of terrestrial animals possessing this sexual polymorphism. Sexual material is exchanged between both animals via spermatophore, which can then be stored in the spermatheca. After exchange of spermatozoa, both animals will lay fertilized eggs after a period of gestation; then the eggs will proceed to hatch after a development period. Snails typically reproduce from early spring through late autumn.
How many species of andromonecious plants are there?
Andromonecy occurs in about 4000 species of flowering plants (2% of flowering plants).
Overview
Anatomy and physiology
Leeches show a remarkable similarity to each other in morphology, very different from typical annelids which are cylindrical with a fluid-filled space, the coelom (body cavity). In leeches, the coelom is reduced to four slender longitudinal channels, and the interior of the body is filled with a solid dermis in between the various organs. Typically, the body is dorso-ventrally flattened and tapers at both ends. Longitudinal and circular muscles in the body wall are supplemented by dia…
Diversity and phylogeny
Some 680 species of leech have been described, of which around 100 are marine, 480 freshwater and the remainder terrestrial. Among Euhirudinea, the true leeches, the smallest is about 1 cm (1⁄2 in) long, and the largest is the giant Amazonian leech, Haementeria ghilianii, which can reach 30 cm (12 in). Except for Antarctica, leeches are found throughout the world but are at their most abundant in temperate lakes and ponds in the northern hemisphere. The majority of freshwater l…
Interactions with humans
Leech bites are generally alarming rather than dangerous, though a small percentage of people have severe allergic or anaphylactic reactions and require urgent medical care. Symptoms of these reactions include red blotches or an itchy rash over the body, swelling around the lips or eyes, a feeling of faintness or dizziness, and difficulty in breathing. An externally attached leech will detach and fall off on its own accord when it is satiated on blood, which may take from twenty …
General bibliography
• Ruppert, Edward E.; Fox, Richard S.; Barnes, Robert D. (2004). Invertebrate Zoology, 7th Edition. Cengage Learning. ISBN 978-81-315-0104-7.
External links
• Media related to Hirudinea at Wikimedia Commons
• Data related to Hirudinea at Wikispecies
• The dictionary definition of leech at Wiktionary
Clinical Overview
- Use
Leeches have been used for bloodletting, wound healing, and stimulating blood flow at postsurgical sites. Use in osteoarthritis is being investigated, but there is a lack of clinical information to make recommendations. - Dosing
Consult existing guidelines for the use of leeches.
Biology
- There are more than 700 species of leeches, all of which are carnivorous.1The leech is an hermaphrodite, containing both male and female sexual organs, but is not self-fertile. The use of medicinal leeches (H. medicinalis) is preferred because of their ability to bite deeply and cause prolonged bleeding even after they are detached. H. medicinalis ...
History
- The medicinal use of leeches dates back to ancient Egyptians around 1300 BC; the Greek physician Galen (130 to 201 AD) commonly used leeches for bloodletting. The 19th century heralded the widespread use of leeches for bloodletting—leading to a leech shortage from 1825 to 1850 in France requiring the importation of leeches from America.1, 2, 3, 4, 5, 6 By the end of th…
Chemistry
- Different species of leeches secrete varying compounds with differing hematological actions.7, 8 Following attachment, H. medicinalis secretes hirudin, a selective thrombin inhibitor, which enhances bleeding and prevents coagulation.1, 9, 10 Hirudin was first described more than a century ago and characterized as a 65-amino acid peptide with antithrombokinase activity.1 Earl…
Uses and Pharmacology
- Ischemic tissue
Medicinal leeches are used to stimulate the flow of blood at postoperative surgical sites.2, 15, 16 After attaching to the site, leeches secrete compounds, especially hirudin, that reduce blood viscosity. They provide the drainage needed to permit decongestion and to preserve tissue viabil… - Other uses
Based on reported anti-inflammatory substances in the saliva of medicinal leeches, a number of clinical studies have evaluated the role of leeches in osteoarthritis.18, 19 Blinding of participants is problematic in such studies and comparators have used transcutaneous electrical nerve stim…
Dosing
- Institutional guidelines may exist for the use of leeches. Leeches are applied from 2 to 4 times a day for up to a week. Feeding is complete in about 20 minutes, at which time the leech drops off. Removal of the leech may be hastened by applying solutions of salt, vinegar, a flame, or a local anesthetic. Leeches should not be forcibly removed. Bleeding from the attachment site usually c…
Pregnancy / Lactation
- Information regarding safety in pregnancy and lactation is lacking. Avoid use due to risk of infection and anemia.
Interactions
- None well documented. Closely monitor conditions requiring concomitant anticoagulant therapy. One study found no changes in ipsilateral activated partial thromboplastin or prothrombin times when leeches were applied to an intact hand. This suggests that systemic or local anticoagulation is not likely to occur and that the risk of interference with other therapies may be small.27
Adverse Reactions
- Arterial insufficiency, previous exposure to leeches (risk of allergic reaction), immunosuppression (risk of infection), patient refusal to accept possible subsequent blood transfusions, and unstable medical conditions have been described as contraindications for extensive leech therapy.9
Disclaimer
- This information relates to an herbal, vitamin, mineral or other dietary supplement. This product has not been reviewed by the FDA to determine whether it is safe or effective and is not subject to the quality standards and safety information collection standards that are applicable to most prescription drugs. This information should not be used to decide whether or not to take this pro…
Overview
In reproductive biology, a hermaphrodite is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes.
Many taxonomic groups of animals (mostly invertebrates) do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which either partner can act as the female or male. For example, the great majority of tunicates, pulmon…
Etymology
The term derives from the Latin: hermaphroditus, from Ancient Greek: ἑρμαφρόδιτος, romanized: hermaphroditos, which derives from Hermaphroditus (Ἑρμαφρόδιτος), the son of Hermes and Aphrodite in Greek mythology. According to Ovid, he fused with the nymph Salmacis resulting in one individual possessing physical traits of male and female sexes; according to the earlier Diodorus Siculus, he was born with a physical body combining male and female sexes. The word hermap…
Animals
Sequential hermaphrodites (dichogamy) occur in species in which the individual is born as one sex, but can later change into the opposite sex. This contrasts simultaneous hermaphrodites, in which an individual may possess fully functional male and female genitalia. Sequential hermaphroditism is common in fish (particularly teleost fish) and many gastropods (such as the common slipper shell), and some flowering plants. Sequential hermaphrodites can only change sex once. Sequential …
Plants
Hermaphrodite is used in botany to describe, for example, a flower that has both staminate (male, pollen-producing) and carpellate (female, ovule-producing) parts.
Flowering plant species with separate male and female flowers on the same individual are called monoecious. Monoecious plants are often referred to as hermaphroditic because they produce both male and female gametes. However, the individual flowers are not hermaphroditic becaus…
Use regarding humans
Historically, the term hermaphrodite was used in law to refer to people whose sex was in doubt. The 12th-century Decretum Gratiani states that "Whether an hermaphrodite may witness a testament, depends on which sex prevails" ("Hermafroditus an ad testamentum adhiberi possit, qualitas sexus incalescentis ostendit."). Similarly, the 17th-century English jurist and judge Edward Coke (Lord Coke), wrote in his Institutes of the Lawes of England on laws of succession stating, "…
Evolution
The evolution of anisogamy may have contributed to the evolution of simultaneous hermaphroditism and sequential hermaphroditism but, as of 2016 it remains unclear if the evolution of anisogamy first led to hermaphroditism or gonochorism. It is possible that hermaphroditism evolved from gonochorism, or vice versa. Most studies on its evolution focus on plants, and its evolution in animals is unclear as of December 2017 .
See also
• Asexual reproduction
• Trioecy
• Androgyny
• Gonochorism
• Gynandromorph
Further reading
• "Bony Fishes: Reproduction". SeaWorld/Busch Gardens Animal Infobooks. Busch Entertainment Corporation. 2009. Archived from the original on 25 July 2011. Retrieved 12 September 2009.
• Discovery Health Channel, (2007) "I Am My Own Twin"
• Kim KR, Kwon Y, Joung JY, Kim KS, Ayala AG, Ro JY (October 2002). "True hermaphroditism and mixed gonadal dysgenesis in young children: a clinicopathologic study of 10 cases". Modern Pathology. 15 (10): 1013–9. doi:10.109…