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32-419: The Aphididae are a very large insect family in the aphid superfamily ( Aphidoidea ), of the order Hemiptera . These insects suck the sap from plant leaves. Several thousand species are placed in this family , many of which are considered plant/crop pests. They are the family of insects containing most plant virus vectors (around 200 known) with the green peach aphid ( Myzus persicae ) being one of

64-404: A diminutive usually refer particularly to a hook at the tip, whereas diminutive terms such as hamulose tend to imply that something is beset with small hooks. In vertebrate anatomy, a hamulus is a small, hook-shaped portion of a bone, or possibly of other hard tissue. In human anatomy, examples include: In arthropod morphology, hamuli are hooklets, usually in the form of projections of

96-452: A functional furcula , the underside of the third abdominal segment bears a hooked structure, variously called the retinaculum or hamula. It holds the furcula ready for release in times of emergency. The terms also are used in descriptive anatomy of some insect genitalia, such as hamuli in various Odonata and "hamus" for the hooked part of the uncus in male Lepidoptera . In botany , such words largely refer to hooked bristles such as

128-563: A hundred species, are marine. Insects such as snow scorpionflies flourish in cold habitats including the Arctic and at high altitude. Insects such as desert locusts , ants, beetles, and termites are adapted to some of the hottest and driest environments on earth, such as the Sonoran Desert . Insects form a clade , a natural group with a common ancestor, among the arthropods . A phylogenetic analysis by Kjer et al. (2016) places

160-504: A year, peaking mid year and then declining. Members of the Aphididae are soft-bodied, pear-shaped insects called aphids, as are other members of the superfamily Aphidoidea. Most of them have a pair of little tubes, called cornicles , projecting dorsally from the posterior of their abdomens . The cornicles have been variously interpreted as organs of excretion or for the production of honeydew, but their only confirmed function to date

192-488: Is hami . Hamulus is the diminutive – hooklet or little hook. The plural is hamuli . Adjectives are hamate and hamulate , as in "a hamulate wing-coupling", in which the wings of certain insects in flight are joined by hooking hamuli on one wing into folds on a matching wing. Hamulate can also mean "having hamuli". The terms hamose , hamular , hamous and hamiform also have been used to mean "hooked", or "hook-shaped". Terms such as hamate that do not indicate

224-423: Is constrained by the inelastic exoskeleton, so development involves a series of molts . The immature stages often differ from the adults in structure, habit and habitat. Groups that undergo four-stage metamorphosis often have a nearly immobile pupa . Insects that undergo three-stage metamorphosis lack a pupa, developing through a series of increasingly adult-like nymphal stages. The higher level relationship of

256-696: Is known as cyclical parthenogenesis and, in temperate regions, sexual reproduction occurs in autumn and results in the production of overwintering eggs, which hatch the following spring and initiate another cycle. Many pest aphids, however, do not overwinter as an egg but as nymphs or adults and others as both eggs and active stages (see Williams and Dixon 2007). For their size, the parthenogenetic individuals have very short developmental times and potentially prodigious rates of increase (de Réaumur 1737; Huxley 1858; Kindlmann and Dixon 1989; Dixon 1992). Thus, aphids show very complex and rapidly changing within-year dynamics, with each clone going through several generations during

288-407: Is only partly contained in vessels, and some circulates in an open hemocoel . Insect vision is mainly through their compound eyes , with additional small ocelli . Many insects can hear, using tympanal organs , which may be on the legs or other parts of the body. Their sense of smell is via receptors, usually on the antennae and the mouthparts. Nearly all insects hatch from eggs . Insect growth

320-403: Is that they produce fatty alarm pheromones when the insects are attacked by predators. When wings are present they occur only on particular morphs called " alates ", and wingless morphs are said to be " apterous ". The forewing ( mesothoracic wing) of the alate in the Aphididae has four to six veins attached to a major vein-like structure that has been interpreted as the combined stems of all

352-853: The Latin word insectum from in , "cut up", as insects appear to be cut into three parts. The Latin word was introduced by Pliny the Elder who calqued the Ancient Greek word ἔντομον éntomon "insect" (as in entomology ) from ἔντομος éntomos "cut in pieces"; this was Aristotle 's term for this class of life in his biology , also in reference to their notched bodies. The English word insect first appears in 1601 in Philemon Holland 's translation of Pliny. In common speech, insects and other terrestrial arthropods are often called bugs . Entomologists to some extent reserve

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384-2281: The Paraneoptera , and Kjer et al. 2016 for the Holometabola . The numbers of described extant species (boldface for groups with over 100,000 species) are from Stork 2018. Archaeognatha (hump-backed/jumping bristletails, 513 spp) [REDACTED] Zygentoma (silverfish, firebrats, fishmoths, 560 spp) [REDACTED] Odonata (dragonflies and damselflies, 5,899 spp) [REDACTED] Ephemeroptera (mayflies, 3,240 spp) [REDACTED] Zoraptera (angel insects, 37 spp) [REDACTED] Dermaptera (earwigs, 1,978 spp) [REDACTED] Plecoptera (stoneflies, 3,743 spp) [REDACTED] Orthoptera (grasshoppers, crickets, katydids, 23,855 spp) [REDACTED] Grylloblattodea (ice crawlers, 34 spp) [REDACTED] Mantophasmatodea (gladiators, 15 spp) [REDACTED] Phasmatodea (stick insects, 3,014 spp) [REDACTED] Embioptera (webspinners, 463 spp) [REDACTED] Mantodea (mantises, 2,400 spp) [REDACTED] Blattodea (cockroaches and termites, 7,314 spp) [REDACTED] Psocodea (book lice, barklice and sucking lice, 11,000 spp) [REDACTED] [REDACTED] Hemiptera (true bugs, 103,590 spp) [REDACTED] Thysanoptera (thrips, 5,864 spp) [REDACTED] Hymenoptera (sawflies, wasps, bees, ants, 116,861 spp) [REDACTED] Strepsiptera (twisted-wing flies, 609 spp) [REDACTED] Coleoptera (beetles, 386,500 spp) [REDACTED] Raphidioptera (snakeflies, 254 spp) [REDACTED] Neuroptera (lacewings, 5,868 spp) [REDACTED] Megaloptera (alderflies and dobsonflies, 354 spp) [REDACTED] Lepidoptera (butterflies and moths, 157,338 spp) [REDACTED] Trichoptera (caddisflies, 14,391 spp) [REDACTED] Diptera (true flies, 155,477 spp) [REDACTED] Mecoptera (scorpionflies, 757 spp) [REDACTED] Siphonaptera (fleas, 2,075 spp) [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] Hamulus The terms are directly from Latin , in which hamus means " hook ". The plural

416-567: The Sternorrhyncha , the suborder of aphids and scale insects . In the Sternorrhyncha such wing coupling occurs particularly in the males of some species. The rear wings of that suborder frequently are reduced or absent, and in many species the last vestige of the rear wing to persist is a futile little strap holding the hamuli, still hooking into the fold of the large front wings. In those springtails (Collembola) that have

448-449: The UF / IFAS Featured Creatures Web site: Insect Insects (from Latin insectum ) are hexapod invertebrates of the class Insecta . They are the largest group within the arthropod phylum . Insects have a chitinous exoskeleton , a three-part body ( head , thorax and abdomen ), three pairs of jointed legs , compound eyes , and a pair of antennae . Insects are

480-623: The insects is unclear. Fossilized insects of enormous size have been found from the Paleozoic Era, including giant dragonfly-like insects with wingspans of 55 to 70 cm (22 to 28 in). The most diverse insect groups appear to have coevolved with flowering plants . Adult insects typically move about by walking and flying; some can swim. Insects are the only invertebrates that can achieve sustained powered flight; insect flight evolved just once. Many insects are at least partly aquatic , and have larvae with gills; in some species,

512-483: 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 many insects as pests , especially those that damage crops, and attempt to control them using insecticides and other techniques. Others are parasitic , and may act as vectors of diseases . Insect pollinators are essential to

544-623: The Hemiptera (true bugs), Lepidoptera (butterflies and moths), Diptera (true flies), Hymenoptera (wasps, ants, and bees), and Coleoptera (beetles), each with more than 100,000 described species. Insects are distributed over every continent and almost every terrestrial habitat. There are many more species in the tropics , especially in rainforests , than in temperate zones. The world's regions have received widely differing amounts of attention from entomologists. The British Isles have been thoroughly surveyed, so that Gullan and Cranston 2014 state that

576-404: The adults too are aquatic. Some species, such as water striders , can walk on the surface of water. Insects are mostly solitary, but some, such as bees , ants and termites , are social and live in large, well-organized colonies . Others, such as earwigs , provide maternal care, guarding their eggs and young. Insects can communicate with each other in a variety of ways. Male moths can sense

608-513: The excess carbohydrates. Honeydew is used as food by ants , honeybees , and many other insects. There is considerable controversy in the classification of aphids, with conservative classifications recognizing as many as 24 subfamilies within a single family Aphididae and others elevating various subfamilies to establish as many as 9 other families within Aphidoidea in addition to Aphididae. The Aphid Species File currently (2021) lists: On

640-538: The form of a relatively long, segmented rostrum , and fairly long antennae . These insects are so small (a few millimeters in length), that winds can transport them for fairly long distances. They are often green, but might be red or brown, as well. They move quite slowly and cannot jump or hop. Aphids excrete a sugary liquid called honeydew , because the plant sap from which they feed contains excess carbohydrates relative to its low protein content. To satisfy their protein needs, they absorb large amounts of sap and excrete

672-555: The host plant is very favourable and a long intervening period when it is less favourable, is well documented for tree dwelling aphids. This has greatly facilitated the modelling of their population dynamics. In general the aphid carrying capacity of annual crop plants tends to increase with the season until the plants mature after which it tends to decrease very rapidly. Thus, the aphid carrying capacity of trees tends to be high in spring and autumn and low in summer, whereas that particularly of short-season annual crops tends to be low early in

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704-608: The insects among the Hexapoda , six-legged animals with segmented bodies; their closest relatives are the Diplura (bristletails). Collembola (springtails) [REDACTED] Protura (coneheads) [REDACTED] Diplura (two-pronged bristletails) [REDACTED] Insecta (=Ectognatha) [REDACTED] The internal phylogeny is based on the works of Wipfler et al. 2019 for the Polyneoptera , Johnson et al. 2018 for

736-446: The most diverse group of animals, with more than a million described species ; they represent more than half of all animal species. The insect nervous system consists of a brain and a ventral nerve cord . Most insects reproduce by laying eggs . Insects breathe air through a system of paired openings along their sides, connected to small tubes that take air directly to the tissues. The blood therefore does not carry oxygen; it

768-547: The most prevalent and indiscriminate carriers. Aphids originated in the late Cretaceous about 100  million years ago (Mya), but the Aphidinae which comprises about half of the 4700 described species and genera of aphids alive today come from their most recent radiation which occurred in the late Tertiary less than 10 Mya. Most aphid species can reproduce both asexually and sexually, with several parthenogenetic generations between each period of sexual reproduction. This

800-402: The name "bugs" for a narrow category of " true bugs ", insects of the order Hemiptera , such as cicadas and shield bugs . Other terrestrial arthropods, such as centipedes , millipedes , woodlice , spiders , mites and scorpions , are sometimes confused with insects, since they have a jointed exoskeleton. Adult insects are the only arthropods that ever have wings, with up to two pairs on

832-431: The other major wing veins . That structure ends in a stigma, a solid spot on the anterior margin of the forewing. The rear (metathoracic) wings have a similar scheme, but simpler in structure, with no stigma The rear wing however, does bear a hamulus , a small hook that, when in flight, engages the claval fold of the forewing, keeping the wing beats in synchrony . All aphids have very small eyes, sucking mouthparts in

864-506: The phloem; in summer leaves are mature and export mainly sugars. In autumn, the leaves senesce and export amino acids and other nutrients. Thus on trees the leaves are most suitable for aphids in spring and autumn. The differences in within-year population dynamics of aphids are due to differences in the effect these seasonal fluctuations in host plant quality have on the per capita rate of increase and intraspecific competition in each species. This annual cycle, consisting of two short periods when

896-535: The reproduction of many flowering plants and so to their ecosystems. Many insects are ecologically beneficial as predators of pest insects, while a few provide direct economic benefit. Two species in particular are economically important and were domesticated many centuries ago: silkworms for silk and honey bees for honey . Insects are consumed as food in 80% of the world's nations, by people in roughly 3000 ethnic groups. Human activities are having serious effects on insect biodiversity . The word insect comes from

928-453: The surface of the exoskeleton . Hami might be actual evaginations of the whole thickness of the exoskeleton. The best-known examples are probably the row of hamuli on the anterior edge of the metathoracic (rear) wings of Hymenoptera such as the honeybee. The hooks attach to a fold on the posterior edge of the mesothoracic (front) wings. It is less widely realised that similar hamuli, though usually fewer, are used in wing coupling in

960-527: The thorax. Whether winged or not, adult insects can be distinguished by their three-part body plan, with head, thorax, and abdomen; they have three pairs of legs on the thorax. Estimates of the total number of insect species vary considerably, suggesting that there are perhaps some 5.5 million insect species in existence, of which about one million have been described and named. These constitute around half of all eukaryote species, including animals , plants , and fungi . The most diverse insect orders are

992-525: The total of around 22,500 species is probably within 5% of the actual number there; they comment that Canada's list of 30,000 described species is surely over half of the actual total. They add that the 3000 species of the American Arctic must be broadly accurate. In contrast, a large majority of the insect species of the tropics and the southern hemisphere are probably undescribed. Some 30–40,000 species inhabit freshwater ; very few insects, perhaps

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1024-440: The vegetative season and being made up of many individuals, which can be widely scattered in space. The survival of the eggs and/or overwintering aphids determines the numbers of aphids present the following spring. The within-year dynamics of aphids are largely determined by seasonal changes in host quality. Aphids do best when amino acids are actively translocated in the phloem. In spring, the leaves grow and import amino acids via

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