Beetles are a group of insects that form the order Coleoptera, in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, distinguishing them from most other insects; the Coleoptera, with about 400,000 species, is the largest of all orders, constituting 40% of described insects and 25% of all known animal life-forms. The largest of all families, the Curculionidae with some 70,000 member species, belongs to this order. Found in every habitat except the sea and the polar regions, they interact with their ecosystems in several ways: beetles feed on plants and fungi, break down animal and plant debris, eat other invertebrates; some species are serious agricultural pests, such as the Colorado potato beetle, while others such as Coccinellidae eat aphids, scale insects and other plant-sucking insects that damage crops. Beetles have a hard exoskeleton including the elytra, though some such as the rove beetles have short elytra while blister beetles have softer elytra; the general anatomy of a beetle is quite uniform and typical of insects, although there are several examples of novelty, such as adaptations in water beetles which trap air bubbles under the elytra for use while diving.
Beetles are endopterygotes, which means that they undergo complete metamorphosis, with a series of conspicuous and abrupt changes in body structure between hatching and becoming adult after a immobile pupal stage. Some, such as stag beetles, have a marked sexual dimorphism, the males possessing enormously enlarged mandibles which they use to fight other males. Many beetles are aposematic, with bright colours and patterns warning of their toxicity, while others are harmless Batesian mimics of such insects. Many beetles, including those that live in sandy places, have effective camouflage. Beetles are prominent in human culture, from the sacred scarabs of ancient Egypt to beetlewing art and use as pets or fighting insects for entertainment and gambling. Many beetle groups are brightly and attractively coloured making them objects of collection and decorative displays. Over 300 species are used as food as larvae. However, the major impact of beetles on human life is as agricultural and horticultural pests.
Serious pests include the boll weevil of cotton, the Colorado potato beetle, the coconut hispine beetle, the mountain pine beetle. Most beetles, however, do not cause economic damage and many, such as the lady beetles and dung beetles are beneficial by helping to control insect pests; the name of the taxonomic order, comes from the Greek koleopteros, given to the group by Aristotle for their elytra, hardened shield-like forewings, from koleos and pteron, wing. The English name beetle comes from the Old English word bitela, little biter, related to bītan, leading to Middle English betylle. Another Old English name for beetle is ċeafor, used in names such as cockchafer, from the Proto-Germanic *kebrô. Beetles are by far the largest order of insects: the 400,000 species make up about 40% of all insect species so far described, about 25% of all animals. A 2015 study provided four independent estimates of the total number of beetle species, giving a mean estimate of some 1.5 million with a "surprisingly narrow range" spanning all four estimates from a minimum of 0.9 to a maximum of 2.1 million beetle species.
The four estimates made use of host-specificity relationships, ratios with other taxa, plant:beetle ratios, extrapolations based on body size by year of description. Beetles are found in nearly all habitats, including freshwater and coastal habitats, wherever vegetative foliage is found, from trees and their bark to flowers and underground near roots - inside plants in galls, in every plant tissue, including dead or decaying ones; the heaviest beetle, indeed the heaviest insect stage, is the larva of the goliath beetle, Goliathus goliatus, which can attain a mass of at least 115 g and a length of 11.5 cm. Adult male goliath beetles are the heaviest beetle in its adult stage, weighing 70–100 g and measuring up to 11 cm. Adult elephant beetles, Megasoma elephas and Megasoma actaeon reach 50 g and 10 cm; the longest beetle is the Hercules beetle Dynastes hercules, with a maximum overall length of at least 16.7 cm including the long pronotal horn. The smallest recorded beetle and the smallest free-living insect, is the featherwing beetle Scydosella musawasensis which may measure as little as 325 µm in length.
The oldest known fossil insect that unequivocally resembles a Coleopteran is from the Lower Permian Period about 270 million years ago, though these members of the family Tshekardocoleidae have 13-segmented antennae, elytra with more developed venation and more irregular longitudinal ribbing, abdomen and ovipositor extending beyond the apex of the elytra. In the Permian–Triassic extinction event at the end of the Permian, some 30% of all insect species became extinct, so the fossil record of insects only includes beetles from the Lower Triassic 220 mya. Around this time, during the Late Triassic, fungus-feeding species such as Cupedidae appear in the fossil record. In the stages of the Upper Triassic, alga-feeding insects such as Triaplidae and Hydrophilidae begin to appear, alongside predatory water beetles; the first weevils, including the Obrienidae, appear alongside the first rove beetles, which resemb
Insects or Insecta are hexapod invertebrates and the largest group within the arthropod phylum. Definitions and circumscriptions vary; as used here, the term Insecta is synonymous with Ectognatha. Insects have a chitinous exoskeleton, a three-part body, three pairs of jointed legs, compound eyes and one pair of antennae. Insects are the most diverse group of animals; the total number of extant species is estimated at between ten million. Insects may be found in nearly all environments, although only a small number of species reside in the oceans, which are dominated by another arthropod group, crustaceans. Nearly all insects hatch from eggs. Insect growth is constrained by the inelastic exoskeleton and development involves a series of molts; the immature stages differ from the adults in structure and habitat, can include a passive pupal stage in those groups that undergo four-stage metamorphosis. Insects that undergo three-stage metamorphosis lack a pupal stage and adults develop through a series of nymphal stages.
The higher level relationship of the insects is unclear. Fossilized insects of enormous size have been found from the Paleozoic Era, including giant dragonflies with wingspans of 55 to 70 cm; the most diverse insect groups appear to have coevolved with flowering plants. Adult insects move about by walking, flying, or sometimes swimming; as it allows for rapid yet stable movement, many insects adopt a tripedal gait in which they walk with their legs touching the ground in alternating triangles, composed of the front & rear on one side with the middle on the other side. Insects are the only invertebrates to have evolved flight, all flying insects derive from one common ancestor. Many insects spend at least part of their lives under water, with larval adaptations that include gills, some adult insects are aquatic and have adaptations for swimming; some species, such as water striders, are capable of walking on the surface of water. Insects are solitary, but some, such as certain bees and termites, are social and live in large, well-organized colonies.
Some insects, such as earwigs, show maternal care, guarding their eggs and young. Insects can communicate with each other in a variety of ways. Male moths can sense the pheromones of female moths over great distances. Other species communicate with sounds: crickets stridulate, or rub their wings together, to attract a mate and repel other males. Lampyrid beetles communicate with light. Humans regard certain insects as pests, attempt to control them using insecticides, a host of other techniques; some insects damage crops by feeding on sap, fruits, or wood. Some species are parasitic, may vector diseases; some insects perform complex ecological roles. Insect pollinators are essential to the life cycle of many flowering plant species on which most organisms, including humans, are at least dependent. Many insects are considered ecologically beneficial as predators and a few provide direct economic benefit. Silkworms produce silk and honey bees produce honey and both have been domesticated by humans.
Insects are consumed as food in 80% of the world's nations, by people in 3000 ethnic groups. Human activities have effects on insect biodiversity; the word "insect" comes from the Latin word insectum, meaning "with a notched or divided body", or "cut into", from the neuter singular perfect passive participle of insectare, "to cut into, to cut up", from in- "into" and secare "to cut". A calque of Greek ἔντομον, "cut into sections", Pliny the Elder introduced the Latin designation as a loan-translation of the Greek word ἔντομος or "insect", Aristotle's term for this class of life in reference to their "notched" bodies. "Insect" first appears documented in English in 1601 in Holland's translation of Pliny. Translations of Aristotle's term form the usual word for "insect" in Welsh, Serbo-Croatian, etc; the precise definition of the taxon Insecta and the equivalent English name "insect" varies. In the broadest circumscription, Insecta sensu lato consists of all hexapods. Traditionally, insects defined in this way were divided into "Apterygota" —the wingless insects—and Pterygota—the winged insects.
However, modern phylogenetic studies have shown that "Apterygota" is not monophyletic, so does not form a good taxon. A narrower circumscription restricts insects to those hexapods with external mouthparts, comprises only the last three groups in the table. In this sense, Insecta sensu stricto is equivalent to Ectognatha. In the narrowest circumscription, insects are restricted to hexapods that are either winged or descended from winged ancestors. Insecta sensu strictissimo is equivalent to Pterygota. For the purposes of this article, the middle definition is used; the evolutionary relationship of insects to other animal groups remains unclear. Although traditionally grouped with millipedes and centiped
Bioluminescence is the production and emission of light by a living organism. It is a form of chemiluminescence. Bioluminescence occurs in marine vertebrates and invertebrates, as well as in some fungi, microorganisms including some bioluminescent bacteria and terrestrial invertebrates such as fireflies. In some animals, a firefly squid has bioluminescence, the light is bacteriogenic, produced by symbiotic organisms such as Vibrio bacteria. In a general sense, the principal chemical reaction in bioluminescence involves some light-emitting molecule and an enzyme called the luciferin and the luciferase, respectively; because these are generic names, the luciferins and luciferases are distinguished by including the species or group, i.e. Firefly luciferin. In all characterized cases, the enzyme catalyzes the oxidation of the luciferin. In some species, the luciferase requires other cofactors, such as calcium or magnesium ions, sometimes the energy-carrying molecule adenosine triphosphate. In evolution, luciferins vary little: one in particular, coelenterazine, is found in eleven different animal, though in some of these, the animals obtain it through their diet.
Conversely, luciferases vary between different species, bioluminescence has arisen over forty times in evolutionary history. Both Aristotle and Pliny the Elder mentioned that damp wood sometimes gives off a glow and many centuries Robert Boyle showed that oxygen was involved in the process, both in wood and in glow-worms, it was not until the late nineteenth century. The phenomenon is distributed among animal groups in marine environments where dinoflagellates cause phosphorescence in the surface layers of water. On land it occurs in fungi and some groups of invertebrates, including insects; the uses of bioluminescence by animals include counter-illumination camouflage, mimicry of other animals, for example to lure prey, signalling to other individuals of the same species, such as to attract mates. In the laboratory, luciferase-based systems are used in genetic engineering and for biomedical research. Other researchers are investigating the possibility of using bioluminescent systems for street and decorative lighting, a bioluminescent plant has been created.
Before the development of the safety lamp for use in coal mines, dried fish skins were used in Britain and Europe as a weak source of light. This experimental form of illumination avoided the necessity of using candles which risked sparking explosions of firedamp. Another safe source of illumination in mines was bottles containing fireflies. In 1920, the American zoologist E. Newton Harvey published a monograph, The Nature of Animal Light, summarizing early work on bioluminescence. Harvey notes that Aristotle mentions light produced by dead fish and flesh, that both Aristotle and Pliny the Elder mention light from damp wood, he records that Robert Boyle experimented on these light sources, showed that both they and the glow-worm require air for light to be produced. Harvey notes that in 1753, J. Baker identified the flagellate Noctiluca "as a luminous animal" "just visible to the naked eye", in 1854 Johann Florian Heller identified strands of fungi as the source of light in dead wood. Tuckey, in his posthumous 1818 Narrative of the Expedition to the Zaire, described catching the animals responsible for luminescence.
He mentions pellucids and cancers. Under the microscope he described the "luminous property" to be in the brain, resembling "a most brilliant amethyst about the size of a large pin's head". Charles Darwin noticed bioluminescence in the sea, describing it in his Journal: While sailing in these latitudes on one dark night, the sea presented a wonderful and most beautiful spectacle. There was a fresh breeze, every part of the surface, which during the day is seen as foam, now glowed with a pale light; the vessel drove before her bows two billows of liquid phosphorus, in her wake she was followed by a milky train. As far as the eye reached, the crest of every wave was bright, the sky above the horizon, from the reflected glare of these livid flames, was not so utterly obscure, as over the rest of the heavens. Darwin observed a luminous "jelly-fish of the genus Dianaea" and noted that "When the waves scintillate with bright green sparks, I believe it is owing to minute crustacea, but there can be no doubt that many other pelagic animals, when alive, are phosphorescent."
He guessed that "a disturbed electrical condition of the atmosphere" was responsible. Daniel Pauly comments that Darwin "was lucky with most of his guesses, but not here", noting that biochemistry was too little known, that the complex evolution of the marine animals involved "would have been too much for comfort". Bioluminescence attracted the attention of the United States Navy in the Cold War, since submarines in some waters can create a bright enough wake to be detected; the navy was interested in predicting when such detection would be possible, hence guiding their own submarines to avoid detection. Among the anecdotes of navigation by bioluminescence, the Apollo 13 astronaut Jim Lovell recounted how as a navy pilot he had found his way back to his aircraft carrier USS Shangri-La when his navigation systems failed. Turning off his cabin lights, he saw the glowing wake of the ship, was able to fly to it and land safely; the French pharmacologist Raphaël Dubois carried out work on bioluminescen
An arthropod is an invertebrate animal having an exoskeleton, a segmented body, paired jointed appendages. Arthropods form the phylum Euarthropoda, which includes insects, arachnids and crustaceans; the term Arthropoda as proposed refers to a proposed grouping of Euarthropods and the phylum Onychophora. Arthropods are characterized by their jointed limbs and cuticle made of chitin mineralised with calcium carbonate; the arthropod body plan consists of each with a pair of appendages. The rigid cuticle inhibits growth, so arthropods replace it periodically by moulting. Arthopods are bilaterally symmetrical and their body possesses an external skeleton; some species have wings. Their versatility has enabled them to become the most species-rich members of all ecological guilds in most environments, they have over a million described species, making up more than 80 per cent of all described living animal species, some of which, unlike most other animals, are successful in dry environments. Arthropods range in size from the microscopic crustacean Stygotantulus up to the Japanese spider crab.
Arthropods' primary internal cavity is a haemocoel, which accommodates their internal organs, through which their haemolymph – analogue of blood – circulates. Like their exteriors, the internal organs of arthropods are built of repeated segments, their nervous system is "ladder-like", with paired ventral nerve cords running through all segments and forming paired ganglia in each segment. Their heads are formed by fusion of varying numbers of segments, their brains are formed by fusion of the ganglia of these segments and encircle the esophagus; the respiratory and excretory systems of arthropods vary, depending as much on their environment as on the subphylum to which they belong. Their vision relies on various combinations of compound eyes and pigment-pit ocelli: in most species the ocelli can only detect the direction from which light is coming, the compound eyes are the main source of information, but the main eyes of spiders are ocelli that can form images and, in a few cases, can swivel to track prey.
Arthropods have a wide range of chemical and mechanical sensors based on modifications of the many setae that project through their cuticles. Arthropods' methods of reproduction and development are diverse; the evolutionary ancestry of arthropods dates back to the Cambrian period. The group is regarded as monophyletic, many analyses support the placement of arthropods with cycloneuralians in a superphylum Ecdysozoa. Overall, the basal relationships of Metazoa are not yet well resolved; the relationships between various arthropod groups are still debated. Aquatic species use either external fertilization. All arthropods lay eggs, but scorpions give birth to live young after the eggs have hatched inside the mother. Arthropod hatchlings vary from miniature adults to grubs and caterpillars that lack jointed limbs and undergo a total metamorphosis to produce the adult form; the level of maternal care for hatchlings varies from nonexistent to the prolonged care provided by scorpions. Arthropods contribute to the human food supply both directly as food, more indirectly as pollinators of crops.
Some species are known to spread severe disease to humans and crops. The word arthropod comes from the Greek ἄρθρον árthron, "joint", πούς pous, i.e. "foot" or "leg", which together mean "jointed leg". Arthropods are invertebrates with jointed limbs; the exoskeleton or cuticles consists of a polymer of glucosamine. The cuticle of many crustaceans, beetle mites, millipedes is biomineralized with calcium carbonate. Calcification of the endosternite, an internal structure used for muscle attachments occur in some opiliones. Estimates of the number of arthropod species vary between 1,170,000 and 5 to 10 million and account for over 80 per cent of all known living animal species; the number of species remains difficult to determine. This is due to the census modeling assumptions projected onto other regions in order to scale up from counts at specific locations applied to the whole world. A study in 1992 estimated that there were 500,000 species of animals and plants in Costa Rica alone, of which 365,000 were arthropods.
They are important members of marine, freshwater and air ecosystems, are one of only two major animal groups that have adapted to life in dry environments. One arthropod sub-group, insects, is the most species-rich member of all ecological guilds in land and freshwater environments; the lightest insects weigh less than 25 micrograms. Some living crustaceans are much larger; the embryos of all arthropods are segmented, built from a series of repeated modules. The last common ancestor of living arthropods consisted of a series of undifferentiated segments, each with a pair of appendages that functioned as limbs. However, all known living and fossil arthropods have grouped segments into tagmata in which segments and their limbs are specialized in various ways; the three-
Pyrophorus noctilucus, common name Headlight Elater, is a species of click beetle. Pyrophorus noctilucus can reach a length of 20–40 millimetres; the basic coloration is dark brown. The antennae are serrate; the pronotum shows a long backward-pointing tooth. These beetles are among the brightest bioluminescent insects. With a brightness of around 45 millilamberts, they are said to be technically bright enough to read by, they achieve their luminescence by means of two light organs at the posterior corners of the prothorax, a broad area on the underside of the first abdominal segment. Their bioluminescence is similar to that of another group of beetles, the fireflies, although click beetles do not flash, but remain glowing; the larvae and the pupae have light organs and the eggs are luminous too. Adults feed on pollen, fermenting fruit and sometimes small insects, while the larvae live in the soil and feed on various plant materials and invertebrates, as well on the larvae of other beetles; this species can be found in Belize, Saint Vincent & the Grenadines, Cayman Islands, Panama, Venezuela and Tobago, Suriname, Ecuador, Bolivia, Hawaii, Puerto Rico, Dominican Republic and Uruguay.
Elateridae in SYNOPSIS OF THE DESCRIBED COLEOPTERA OF THE WORLD Biolib American Insects Harvey, E. N. and K. P. Stevens. 1928. The brightness of the light of the West Indian elaterid beetle, pyrophorus. J. Gen. Physiol. 12: 269-272
Pyrophorus punctatissimus is a species of click beetle. Pyrophorus punctatissimus can reach a length of about 30 millimetres; the basic coloration is dark brown. The antennae are serrate; the pronotum shows a long backward-pointing tooth. These beetles are bioluminescent by means of two luminescent light organs at the posterior corners of the prothorax, a broad area on the underside of the first abdominal segment, their bioluminescence is similar to that of another group of beetles, the fireflies, although click beetles do not flash, but remain glowing. The larvae and the pupae have light organs; this species can be found in Bolivia, Brazil, Paraguay and Cuba. Elateridae in SYNOPSIS OF THE DESCRIBED COLEOPTERA OF THE WORLD Universal Biological Indexer Pybio.org Beetles of Argentina
The Cerrado is a vast tropical savanna ecoregion of Brazil in the states of Goiás, Mato Grosso do Sul, Mato Grosso and Minas Gerais. The Cerrado biome core areas are the plateaus in the center of Brazil; the main habitat types of the Cerrado include: forest savanna, wooded savanna, park savanna and gramineous-woody savanna. Savanna wetlands and gallery forests are included; the second largest of Brazil's major habitat types, after the Amazonian rainforest, the Cerrado accounts for a full 21 percent of the country's land area. The first detailed account of the Brazilian cerrados was provided by Danish botanist Eugenius Warming in the book Lagoa Santa, in which he describes the main features of the cerrado vegetation in the state of Minas Gerais. Since vast amounts of research have proved that the Cerrado is one of the richest of all tropical savanna regions and has high levels of endemism. Characterized by enormous ranges of plant and animal biodiversity, World Wide Fund for Nature named it the biologically richest savanna in the world, with about 10,000 plant species and 10 endemic bird species.
There are nearly 200 species of mammal in the Cerrado. The Cerrado's climate is typical of the wetter savanna regions of the world, with a semi-humid tropical climate; the Cerrado is limited to two dominant seasons throughout the year and dry. Annual temperatures for the Cerrado average between 22 and 27 °C and average precipitation between 800–2000 mm for over 90% of the area; this ecoregion has a strong dry season during the southern winter. The Cerrado is characterized by unique vegetation types, it is composed of a shifting mosaic of habitats, with the savanna-like cerrado itself on well-drained areas between strips of gallery forest which occur along streams. Between the cerrado and the gallery forest is an area of vegetation known as the wet campo with distinct up- and downslope borders where tree growth is inhibited due to wide seasonal fluctuations in the water table; the savanna portion of the Cerrado is heterogeneous in terms of canopy cover. Goodland divided the Cerrado into four categories ranging from least to most canopy cover: campo sujo, campo cerrado, cerrado sensu stricto and cerradao.
Around 800 species of trees are found in the Cerrado. Among the most diverse families of trees in the Cerrado are the Leguminosae, Myrtaceae and Rubiaceae. Much of the Cerrado is dominated by the Vochysiaceae due to the abundance of three species in the genus Qualea; the herbaceous layer reaches about 60 cm in height and is composed of the Poaceae, Leguminosae, Compositae and Rubiaceae. Much of the vegetation in the gallery forests is similar to nearby rainforest. Soil fertility, fire regime and hydrology are thought to be most influential in determining Cerrado vegetation. Cerrado soils are always well-drained and most are oxisols with low pH and low calcium and magnesium; the amount of potassium and phosphorus has been found to be positively correlated with tree trunk basal area in Cerrado habitats. Much as in other grasslands and savannas, fire is important in maintaining and shaping the Cerrado's landscape. Cerrado vegetation is believed to be ancient, stretching back as far in a prototypic form during the Cretaceous before Africa and South America separated.
A dynamic expansion and contraction between cerrado and Amazonian rainforest has occurred with expansion of the Cerrado during glacial periods like the Pleistocene. These processes and the resulting fragmentation have contributed to the high species richness both of the Cerrado and of the Amazonian rainforest; the insects of the Cerrado are understudied. A yearlong survey of the Cerrado at one reserve in Brazil found that the orders Coleoptera, Hymenoptera and Isoptera accounted for 89.5% of all captures. The Cerrado supports high density of leaf cutter ant nests which are very diverse. Along with termites, leaf cutter ants are the primary herbivores of the Cerrado and play an important role in consuming and decomposing organic matter, as well as constituting an important food source to many other animal species; the highest diversity of galling insects in the world is found in the Cerrado, with the most species found at the base of the Serro do Cipó in southeast Brazil. The Cerrado has a high diversity of vertebrates.
Lizard diversity is thought to be low in the Cerrado compared to other areas like caatinga or lowland rainforest although one recent study found 57 species in one cerrado area with the high diversity driven by the availability of open habitat. Ameiva ameiva is among the largest lizards found in the Cerrado and is the most important lizard predator where it is found in the Cerrado. There is a high diversity of snakes in the Cerrado with Colubridae being the richest family; the open nature of the cerrado vegetation most contrib