Labah-labah / Spider

Sunday, October 25, 2009
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Spiders (order Araneae) are air-breathing chelicerate arthropods that have eight legs, and chelicerae modified into fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms.[1] Spiders are found world-wide on every continent except for Antarctica, and have become established in nearly every ecological niche with the exception of air and sea colonization. As of 2008, approximately 40,000 spider species, and 109 families have been recorded by taxonomists;[2] however, there has been confusion within the scientific community as to how all these genera should be classified, as evidenced by the over 20 different classifications that have been proposed since 1900.[3]
Anatomically, spiders differ from other arthropods in that the usual body segments are fused into two tagmata, the cephalothorax and abdomen, and joined by a small, cylindrical pedicel. Unlike insects, spiders do not have antennae. In all except the most primitive group, the Mesothelae, spiders have the most centralized nervous systems of all arthropods, as all their ganglia are fused into one mass in the cephalothorax. Unlike most arthropods, spiders have no extensor muscles in their limbs and instead extend them by hydraulic pressure.
Their abdomens bear appendages that have been modified into spinnerets that extrude silk from up to six types of silk glands within their abdomen. Spider webs vary widely in size, shape and the amount of sticky thread used. It now appears that the spiral orb web may be one of the earliest forms, and spiders that produce tangled cobwebs are more abundant and diverse than orb-web spiders. Spider-like arachnids with silk-producing spigots appear in the Devonian period about 386 million years ago, but these animals apparently lacked spinnerets. True spiders have been found in Carboniferous rocks from 318 to 299 million years ago, and are very similar to the most primitive surviving order, the Mesothelae. The main groups of modern spiders, Mygalomorphae and Araneomorphae, first appear in the Triassic period, before 200 million years ago.
A vegetarian species was described in 2008,[4] but all other known species are predators, mostly preying on insects and on other spiders, although a few large species also take birds and lizards. Spiders use a wide range of strategies to capture prey: trapping it in sticky webs, lassoing it with sticky bolas, mimicking the prey to avoid detection, or running it down. Most detect prey mainly by sensing vibrations, but the active hunters have acute vision, and hunters of the genus Portia show signs of intelligence in their choice of tactics and ability to develop new ones. Spiders' guts are too narrow to take solids, and they liquidize their food by flooding it with digestive enzymes and grinding it with the bases of their pedipalps, as they do not have true jaws.
Male spiders identify themselves by a variety of complex courtship rituals to avoid being eaten by the females. Males of most species survive a few matings, limited mainly by their short life spans. Females weave silk egg-cases, each of which may contain hundreds of eggs. Females of many species care for their young, for example by carrying them around or by sharing food with them. A minority of species are social, building communal webs that may house anywhere from a few to 50,000 individuals. Social behavior ranges from precarious toleration, as in the aggressive widow spiders, to co-operative hunting and food-sharing. Although most spiders live for at most two years, tarantulas and other mygalomorph spiders can live up to 25 years in captivity.
While the venom of a few species is dangerous to humans, scientists are now researching the use of spider venom in medicine and as non-polluting pesticides. Spider silk provides a combination of lightness, strength and elasticity that is superior to that of synthetic materials, and spider silk genes have been inserted into mammals and plants to see if these can be used as silk factories. As a result of their wide range of behaviors, spiders have become common symbols in art and mythology symbolizing various combinations of patience, cruelty and creative powers.
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Mentadak / Mantis

Sunday, October 18, 2009
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Mantodea or mantises is an order of insects which contains approximately 2,200 species in 9 families[1] worldwide in temperate and tropical habitats. Most of the species are in the family Mantidae. Historically, the term "mantid" was used to refer to any member of the order because for most of the past century, only one family was recognized within the order; technically, however, the term only refers to this one family, meaning the species in the other eight recently-established families are not mantids, by definition (i.e., they are empusids, or hymenopodids, etc.), and the term "mantises" should be used when referring to the entire order. A colloquial name for the order is "praying mantises", because of the typical "prayer-like" stance, although the term is often misspelled as "preying mantis" since mantises are notoriously predatory. The word mantis is Greek for "prophet" or "fortune teller". In Europe, the name "praying mantis" refers to Mantis religiosa. The closest relatives of mantises are the orders Isoptera (termites) and Blattodea (cockroaches), and these three groups together are sometimes ranked as an order rather than a superorder. They are sometimes confused with phasmids (stick/leaf insects) and other elongated insects such as grasshoppers and crickets.

Description

Praying Mantises are exclusively predatory. Larger species have been known to prey on small lizards, frogs, birds, snakes, and even rodents, basically anything that it can successfully capture and devour. Most species are known to engage in cannibalism. The majority of mantises are ambush predators, waiting for prey to stray too near. The mantis then lashes out at remarkable speed. Some ground and bark species, however, pursue their prey rather quickly. Surprisingly, though, praying mantises are particularly susceptible to an enzyme found in the mucus excreted by slugs, and thus, their primary enemy is the slug. Prey items are caught and held securely with grasping, spiked forelegs ("raptorial legs"); the first thoracic segment, the prothorax, is commonly elongated and flexibly articulated, allowing for greater range of movement of the front limbs while the remainder of the body remains more or less immobile. The articulation of the head is also remarkably flexible, permitting nearly 300 degrees of movement in some species, allowing for a great range of vision (their compound eyes have a large binocular field of vision) without having to move the remainder of the body. As their hunting relies heavily on vision, they are primarily diurnal, but many species will fly at night.

Reproduction and life history

Sexual cannibalism is common among mantises in captivity, and under some circumstances may also be observed in the field. The female may start feeding by biting off the male’s head (as with any prey), and if mating had begun, the male’s movements may become even more vigorous in its delivery of sperm. Early researchers thought that because copulatory movement is controlled by ganglion in the abdomen, not the head, removal of the male’s head was a reproductive strategy by females to enhance fertilisation while obtaining sustenance. Later, this behaviour appeared to be an artifact of intrusive laboratory observation. Whether the behaviour in the field is natural, or also the result of distractions caused by the human observer, remains controversial. Mantises are highly visual creatures, and notice any disturbance occurring in the laboratory or field such as bright lights or moving scientists. Research by Liske and Davis (1987) and others found (e.g. using video recorders in vacant rooms) that Chinese mantises that had been fed ad libitum (so that they were not starving) actually displayed elaborate courtship behavior when left undisturbed. The male engages the female in courtship dance, to change her interest from feeding to mating. Courtship display has also been observed in other species, but it does not hold for all mantises.
The reason for sexual cannibalism has been debated, with some considering submissive males to be achieving a selective advantage in their ability to produce offspring. This theory is supported by a quantifiable increase in the duration of copulation among males who are cannibalized, in some cases doubling both the duration and the chance of fertilization. This is further supported in a study where males were seen to approach hungry females with more caution, and were shown to remain mounted on hungry females for a longer time, indicating that males actively avoiding cannibalism may mate with multiple females. The act of dismounting is one of the most dangerous times for males during copulation, for it is at this time that females most frequently cannibalize their mates. This increase in mounting duration was thought to indicate that males would be more prone to wait for an opportune time to dismount from a hungry female rather than from a satiated female that would be less likely to cannibalize her mate. Some consider this to be an indication that male submissiveness does not inherently increase male reproductive success, rather that more fit males are likely to approach a female with caution and escape.[2]
The mating season in temperate climates typically begins in autumn. To mate following courtship, the male usually leaps onto the female’s back, and clasps her thorax and wing bases with his forelegs. He then arches his abdomen to deposit and store sperm in a special chamber near the tip of the female’s abdomen. The female then lays between 10 and 400 eggs, depending on the species. Eggs are typically deposited in a frothy mass that is produced by glands in the abdomen. This froth then hardens, creating a protective capsule with a further protective coat, and the egg mass is called an ootheca. Depending on the species these can be attached to a flat surface, wrapped around a plant or even deposited in the ground. Despite the versatility and durability of the eggs, they are often preyed on, especially by several species of parasitic wasps. In a few species, the mother guards the eggs.
As in related insect groups, mantises go through three stages of metamorphosis: egg, nymph, and adult (mantises are among the hemimetabolic insects). The nymph and adult insect are structurally quite similar, except that the nymph is smaller and has no wings or functional genitalia. The nymphs are also sometimes colored differently from the adult, and the early stages are often mimics of ants. A mantis nymph increases in size (often changing its diet as it does so) by replacing its outer body covering with a sturdy, flexible exoskeleton and molting when needed. This can happen up to five to ten times, depending on the species. After the final molt most species have wings, though some species are wingless or brachypterous ("short-winged"), particularly in the female sex.
In tropical species, the natural lifespan of a mantis in the wild is about 10–12 months, but some species kept in captivity have been sustained for 14 months. In colder areas, females will die during the winter (as well as any surviving males).
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Ulat Gonggok / Millipede

Thursday, October 15, 2009
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Millipedes, known as shongololos in South African English, are arthropods that have two pairs of legs per segment (except for the first segment behind the head which does not have any appendages at all, and the next few which only have one pair of legs). Each segment that has two pairs of legs is a result of two single segments fused together as one. Most millipedes have very elongated cylindrical bodies, although some are flattened dorso-ventrally, while pill millipedes are shorter and can roll into a ball, like a pillbug.

Millipedes are detritivores and slow moving. Most millipedes eat decaying leaves and other dead plant matter, moisturising the food with secretions and then scraping it in with the jaws. However they can also be a minor garden pest, especially in greenhouses where they can cause severe damage to emergent seedlings. Signs of millipede damage include the stripping of the outer layers of a young plant stem and irregular damage to leaves and plant apices.

This class contains around 10,000 species. There are 13 orders and 115 families.

The giant African millipede (Archispirostreptus gigas) is the largest species of millipede.

Millipedes can be easily distinguished from the somewhat similar and related centipedes (Class Chilopoda), which move rapidly, and have a single pair of legs for each body segment.

Unlike centipedes however, millipedes are by nature not predators, and due to their slow, non-aggressive behavior and simple diet of decomposing leaves, are easy to keep and ideal as pets.

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Bunga Bawang / Zephyranthes

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Zephyranthes is a genus of about 70 species in the Amaryllis family. Common names for species in this genus include fairy lily, rainflower, zephyr lily, magic lily and rain lily.

According Meerow et al., cladistics suggests that they are native to the Americas. This is important to mention since several species have become naturalized (sometimes unintentionally) in distant places like Hawaii, Indonesia, and Thailand. The species that are native to the higher altitudes in Mexico (e.g. Z. lindleyana) and parts of North America (e.g. Z. longifolia) or Argentina (e.g. Z. candida) represent the species having the greatest potential for cold hardiness.

These perennial geophytes are remarkable for the many ecological niches they tolerate (periodically wet soil to desert conditions), and have many ornamental characteristics worth preserving. Care should be taken with the plants since many of the parts, leaves, bulbs etc. are toxic. Although the genus has been evaluated for possible medicinal properties the biochemically toxic compounds are things like alkaloids. (Kojima et al. 1997.)

Species in the genus which are listed in this article, vary in morphology. Characteristics such as bulb size, tunic color, and leaf morphology help to identify the species. Foliage in the wild is often ephemeral, but under cultivation becomes more persistent. Leaf color ranges from the bright grassy green of Z. candida (shown in the photo) to rather broad glaucous colored foliage such as Z. drummondii. A few of the species have distinct bronze tints in the foliage when grown in bright light. Size of leaves in these species, ranges from dark green and tiny grassy leaves in species like Z.jonesi or Z. longifolia, to broader, glaucous leaves in species like Z. drummondii, and perhaps largest of all, the cultivar commonly known as "Horsetail Falls" which has handsome broad leaves almost like a Hippeastrum.

Flower color in the species ranges from white to yellow (various tints of this color from lemon to sulfur) and pink. Zephyranthes have erect flower stalks which support a flower that may be upward facing or slightly nodding. The funnel-shaped, flowers with six petals can be crocus shaped, but may also open flat such as in Z.jonesii or even reflex slightly. The flowers of some species have a sweet, pleasant fragrance. Fragrance appears to be recessive in crosses, but there are a few species or hybrids, Z. drummondii (white), Z. morrisclintae (pink)and Z.jonesii (light yellow), that all carry the trait. At least 2 of these open their flowers at night and are attractive to nocturnal insects. The flowers typically last only for a day or two; but new flowers may appear in a succession of blooms, especially during humid or rainy weather. Various members of the genus may bloom spring only or repeat and continue into autumn, often a few days after rainstorms thus one of the common names, rainlilies. Periods of synchronous bloom, which breeders have dubbed 'blitzes', are part of their ornamental value, but also times breeders exploit for the purpose of producing new hybrids. (Marta 2005)

Most species under cultivation will bloom without the naturally imposed drought and wet that occurs in nature. Greenhouse grown plants bloom very freely but cycle through periods of bloom. One of the longest blooming of all the species is Z. primulina which blooms from April until October. Although it is apomictic, it is a choice parent for crosses because of its rapid repeat flowering trait and long bloom season. Some other species such as Z. Morrisclintae appear to bloom only in the spring season. Most of these species are easily propagated vegetatively via offsets or twin scaling. A few of them such a Z.clintae are slow to produce increase. Unusual phenotypes can be preserved vegetatively. Sexual reproduction is via seed. The apomictic species freely set seed and faithfully reproduce the maternal phenotype. Sterility in hybrids can be problematic;reasons for this are mentioned below. Seed usually is best sown quickly after harvest, although short term storage can be successful. Maiden seedling can be brought into bloom for some of the hybrid in 8-12 after sowing in ideal conditions. This is great for doing necessary checks for apomixis. Currently these plants are grown in the garden in USDA zones 7 and higher. Hopefully with some attention from breeders new cultivar might increase the plants' cold hardiness. Often the plants are sold in nurseries already potted up, this is a great benefit since the growth cycle is not interrupted. Dried bulbs are marketed wholesale and rarely may be slow to rebloom. Such bulbs usually recover once they have a long growing season after rooting out.

Breeding with these species has some inherent difficulties summarized by M. RoyChowdhury (2006 JAAS) as ranging from pseudogamy and apomixis, differences in chromosome number and varying times of flowering. In spite of these drawbacks interesting breeding work is being done to enhance the value of the plants as ornamentals. Because of the nature botanical restriction breeding programs often encounter impediments. Reciprocal crosses may be difficult because the apomictic parent cannot be used as female parents. However interspecific crosses are well documented (RoyChowdhury 2006). There are tri-hybrids and quad hybrids being produced. (Crossing 3 or 4 distinct species.) Such work indicates that complex hybrids should be possible. One constraint remains that seedlings may still carry the apomictic trait, and it is necessary to have progeny from a test cross to determine this. Mr. John Fellers, Mr. Fadjar Marta and Mr. Tony Avent are just a few of the talented breeders currently working today to increase the potential for these plants. Their work has come to the attention of connoisseurs of the these plants. Colors in man-made crosses currently include red, orange, tan, salmon, blends, picotees and stripes. Floral types such as goblet shaped, wavy petal edges, narrow petals and doubles have been bred (Marta 2005). Complex hybrids may have advantages in holding their flowers open longer, up to three days. While difficult, there have been a few attempts to cross some of these species with related species in the genus Habranthus. Currently it appears that a few crosses with large flowered Habranthus species have been possible for example the cultivar, 'Normal Pearl' which is an intergeneric cross.

The name Zephyranthes comes from Zephyrus, the god of the west wind in Greek mythology.Therefore one translation for a common name might be Westwind Flower. The west wind presumably brings rain that these plants revel in.

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