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Oophagous
Oophagy ( ) sometimes ovophagy, literally "egg eating", is the practice of embryos feeding on eggs produced by the ovary while still inside the mother's uterus. The word oophagy is formed from the classical Greek (, "egg") and classical Greek (, "to eat"). In contrast, adelphophagy is the cannibalism of a multi-celled embryo. Oophagy is thought to occur in all sharks in the order Lamniformes and has been recorded in the bigeye thresher (''Alopias superciliosus''), the pelagic thresher (''A. pelagicus''), the shortfin mako (''Isurus oxyrinchus'') and the porbeagle (''Lamna nasus'') among others. It also occurs in the tawny nurse shark (''Nebrius ferrugineus''), and in the family Pseudotriakidae. This practice may lead to larger embryos or prepare the embryo for a predatory lifestyle. There are variations in the extent of oophagy among the different shark species. The grey nurse shark (''Carcharias taurus'') practices intrauterine cannibalism, the first developed embryo consuming ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelagic Thresher
The pelagic thresher (''Alopias pelagicus'') is a species of thresher shark, family Alopiidae; this group of sharks is characterized by the greatly elongated upper lobes of their caudal fins. The pelagic thresher occurs in the tropical and subtropical waters of the Indian and Pacific Oceans, usually far from shore, but occasionally entering coastal habitats. It is often confused with the common thresher (''A. vulpinus''), even in professional publications, but can be distinguished by the dark, rather than white, color over the bases of its pectoral fins. The smallest of the three thresher species, the pelagic thresher typically measures 3 m (10 ft) long. The diet of the pelagic thresher consists mainly of small midwater fishes, which are stunned with whip-like strikes of its tail. Along with all other mackerel sharks, the pelagic thresher exhibits ovoviviparity and usually gives birth to litters of two. The developing embryos are oophagous, feeding on unfertilized eggs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tawny Nurse Shark
The tawny nurse shark (''Nebrius ferrugineus'') is a species of carpet shark in the family Ginglymostomatidae, and the only extant member of the genus ''Nebrius''. It is found widely along coastlines in the Indo-Pacific, preferring reefs, sandy flats, and seagrass beds from very shallow water to a depth of . With a cylindrical body and a broad, flattened head, the tawny nurse shark is quite similar in appearance to the nurse shark (''Ginglymostoma cirratum'') of the Atlantic and East Pacific, from which it can be distinguished by its pointed-tipped dorsal fins and narrow, sickle-shaped pectoral fins. The maximum recorded length of the tawny nurse shark is . Nocturnal in habits, the tawny nurse shark tends to spend the day resting in piles of two dozen or more individuals inside caves or under ledges. At night, it is an active-swimming predator that uses a powerful suction force to extract prey from inside holes and crevices. The diet of this species consists mainly of octopus, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slender Smooth-hound
The slender smooth-hound or gollumshark (''Gollum attenuatus'') is a species of ground shark in the family Pseudotriakidae. It is endemic to the waters around New Zealand, where it is usually found close to the bottom over the continental slope at depths of . An extremely slim, plain brownish shark reaching in length, the slender smooth-hound can be identified by its broad, flattened head with a long, distinctively bell-shaped snout. Its mouth is angular with short furrows at the corners, and contains a very high number of tooth rows in both jaws. Its two dorsal fins are roughly equal in size. The diet of the slender smooth-hound is diverse, but dominated by small, benthic bony fishes and decapod crustaceans. It exhibits a specialized form of aplacental viviparity with oophagy: the females produce a single capsule in each uterus that contains 30–80 ova, of which one ovum develops into an embryo that consumes the rest of the ova and stores the yolk material in its external y ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bigeye Thresher
The bigeye thresher (''Alopias superciliosus'') is a species of thresher shark, family Alopiidae, found in temperate and tropical oceans worldwide. Like the other thresher sharks, nearly half its total length consists of the elongated upper lobe of the tail fin. Its common name comes from its enormous eyes, which are placed in keyhole-shaped sockets that allow them to be rotated upward. This species can also be distinguished by a pair of deep grooves on the top of its head, from which its scientific name is derived. The large eyes of the bigeye thresher are adapted for hunting in low light conditions. It is one of the few sharks that conduct a diel vertical migration, staying in deep water during the day and moving into surface waters at night to feed. To protect its sensitive brain and eyes from the temperature changes accompanying these movements, the bigeye thresher has a vascular exchange system called the rete mirabile around those organs. This species feeds mainly on fish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryos
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres are arranged as a solid ball that when reaching a certain size, called a morula, takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals. The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of the body. Neurulation forms the nervous s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sharks
Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha (or Selachii) and are the sister group to the rays. However, the term "shark" has also been used to refer to all extinct members of Chondrichthyes with a shark-like morphology, such as hybodonts and xenacanths. The oldest modern sharks are known from the Early Jurassic. They range in size from the small dwarf lanternshark (''Etmopterus perryi''), a deep sea species that is only in length, to the whale shark (''Rhincodon typus''), the largest fish in the world, which reaches approximately in length. Sharks are found in all seas and are common to depths up to . They generally do not live in freshwater, although there are a few known exceptions, such as the bull shark and the river shark, which can be found in both seawater and freshwat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siblicide
Siblicide (attributed by behavioural ecologist Doug Mock to Barbara M. Braun) is the killing of an infant individual by its close relatives (full or half siblings). It may occur directly between siblings or be mediated by the parents, and is driven by the direct fitness benefits to the perpetrator and sometimes its parents. Siblicide has mainly, but not only, been observed in birds. (The word is also used as a unifying term for fratricide and sororicide in the human species; unlike these more specific terms, it leaves the sex of the victim unspecified.) Siblicidal behavior can be either obligate or facultative. Obligate siblicide is when a sibling almost always ends up being killed. Facultative siblicide means that siblicide may or may not occur, based on environmental conditions. In birds, obligate siblicidal behavior results in the older chick killing the other chick(s). In facultative siblicidal animals, fighting is frequent, but does not always lead to death of a sibling; th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Large Garden Bumblebee
''Bombus ruderatus'', the large garden bumblebee or ruderal bumblebee, is a species of long-tongued bumblebee found in Europe and in some parts of northern Africa. This species is the largest bumblebee in Britain and it uses its long face and tongue to pollinate hard-to-reach tubed flowers. Bumblebees are key pollinators in many agricultural ecosystems, which has led to ''B. ruderatus'' and other bumblebees being commercially bred and introduced into non-native countries, specifically New Zealand and Chile. Since its introduction in Chile, ''B. ruderatus'' has spread into Argentina as well. Population numbers have been declining and it has been placed on the Biodiversity Action Plan to help counteract these declines. Taxonomy and phylogeny ''Bombus ruderatus'' is part of the order Hymenoptera and the family Apidae. ''B. ruderatus'' is in the genus Bombus and is one of 239 species of bumblebees, with 23 of those existing in Britain alone. ''B. ruderatus'' is part of the subgenus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xylocopa Sulcatipes
''Xylocopa sulcatipes'' is a large Arabian carpenter bee. These multivoltine bees take part in social nesting and cooperative nesting. They are metasocial carpenter bees that nest in thin dead branches. One or more cooperating females build many brood cells. They have been extensively studied in Saudi Arabia and Israel. Taxonomy and phylogeny ''X. sulcatipes'' is part of the subfamily Xylocopinae within the hymenopteran family Apidae. Xylocopinae is divided into four tribes: Allodapini, Ceratinini, Xylocopini, and Manueliini. The genus ''Xylocopa'', composed of large carpenter bees, consists of about 469 species in 31–51 subgenera, and the species are found throughout the world. ''X. sulcatipes'' is part of the subgenus ''Ctenoxylocopa''. Description and identification ''X. sulcatipes'' differs from other Arabian carpenter bees. Females are distinguishable by the presence of black pubescence (short matted hairs) on the face and the back side of the mesosoma. The mesoscu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polistes Fuscatus
''Polistes fuscatus'', whose common name is the dark or northern paper wasp, is widely found in eastern North America, from southern Canada through the southern United States. It often nests around human development. However, it greatly prefers areas in which wood is readily available for use as nest material, therefore they are also found near and in woodlands and savannas.Evans, H. (1963). ''Wasp Farm.'' Ithaca: Cornell University Press. ''P. fuscatus'' is a social wasp that is part of a complex society based around a single dominant foundress along with other cofoundresses and a dominance hierarchy. Taxonomy and phylogeny ''P. fuscatus'' is a part of the order Hymenoptera, the suborder Apocrita, the family of Vespidae, and the subfamily Polistinae, the second-largest subfamily within the Vespidae, of which all are social wasps.Arevalo, Elisabeth, Yong Zhu, James Carpenter, and Joan Strassmann. (2004). The Phylogeny of the Social Wasp Subfamily Polistinae: Evidencefrom Microsate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parachartergus Fraternus
''Parachartergus fraternus'' is a neotropical, swarm founding, polistine wasp species that is distributed throughout Central and South America.Leonardo, Paula C., Flavio R. Andrade, and Fabio Prezoto. "Foraging Behavior in the Neotropical Swarm-founding Wasp Parachartergus Fraternus (Hymenoptera: Vespidae: Polistinae: Epiponini) during Different Phases of the Biological Cycle." ''Sociobiology'' 42 (2003): 735–43. Web. 11 Oct. 2014. They live in nests in second growth tropical dry forests, near pasture fields, roadside areas, and urban areas as well.Olson, Eric J. "Parachartergus Fraternus (Gribodo)(Hymenoptera: Vespidae: Polistinae) Uses Venom When Taking Caterpillar Prey." ''Psyche: A Journal of Entomology'' 103.1–2 (2000): 85–93. Web. 11 Oct. 2014. These wasps eat insects, such as caterpillars of Lepidoptera. They also drink nectar, honeydew, and water.Mateus, Sidnei, Fernando Barbosa Noll, and Ronaldo Zucchi. "Caste Flexibility and Variation According to the Colony Cycle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leptothorax Acervorum
''Leptothorax acervorum'' is a small brown to yellow ant in the subfamily Myrmicinae. It was first described by Johan Christian Fabricius in 1793. ''L. acervorum'' is vastly distributed across the globe, most commonly found in the coniferous forests of Central, Western and Northern Europe. The morphology of ''L. acervorum'' is extremely similar to that of other '' Leptothorax'' ants. The difference arises in the two-toned appearance of ''L. acervorum'', with the head and metasoma being darker than the mesosoma segment of the body, and hair across its body. Following Bergmann's rule—unusually, for ectothermic animals—body size increases with latitude. Taxonomy ''Leptothorax acervorum'' was first described by Johan Christian Fabricius in 1793 in his publication ''Entomologia systematica emendata et aucta. Vol 2''. The ant belongs to the family of Formicidae, which include all organisms that contain a metapleural gland. Using DNA analysis, the divergence date estimated for clades ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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