Eruciform

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Deceptively caterpillar-like eruciform larvae of typical Symphytan Nematus salicis (Willow sawfly) larvae on willow, Arnhem, the Netherlands.jpg
Deceptively caterpillar-like eruciform larvae of typical Symphytan
Larva of Trichopteran, extended part-way out of its case Trichoptera (aka).jpg
Larva of Trichopteran, extended part-way out of its case

Eruciform (literally: "caterpillar-shaped") is the entomological term describing a certain class of shapes of insect larvae.

Contents

Origin and application

The word "eruciform" literally means "caterpillar-shaped" (from Latin "eruca", a caterpillar — confusingly, in Latin "Eruca" also was used as the name for a rape-like plant, but that has no clear connection to the current context). [1]

One should not take the "caterpillar-shaped" description too seriously; there are many shapes of caterpillars besides the typical silkworm larva, and insect larvae of many shapes, not obviously caterpillar-like, are described as eruciform. Some, for example, are in fact shaped like certain other, straight, eruciform larvae, except that they are curved into a C-shape. These are called "scarabaeiform" because it is the typical form of the larvae of the Scarabaeidae—the scarab beetles and their relatives. In contrast, larvae of the Curculionidae — the weevils — are also called "apodous eruciform", (literally meaning legless caterpillar-shaped; unlike scarab larvae, they do not have legs). This seems rather inconsistent, because commonly weevil larvae are almost as C-shaped as scarab larvae. [2]

Larva of Oryctes nasicornis, Scarabaeidae Engerling Melolontha.jpg
Larva of Oryctes nasicornis , Scarabaeidae
Larva typical of the Curculionidae Larva dunha castana 1.JPG
Larva typical of the Curculionidae

Variations and implications

Some larvae, such as those of most beetles in the family Chrysomelidae, are described as eruciform, although they are short, have swollen abdomens, and have no true "prolegs" such as caterpillars have. Typically they walk freely on leaves and similar surfaces, using the "true" six legs on the three thoracic segments just behind the head. The abdomen is carried behind as a more or less swollen, hump-backed rear end.

In contrast, larvae of the Cerambycidae (Longhorn beetles) are generally straight and could fairly be described as "apodous eruciform". They live in tunnels, typically in wood, where a distended abdomen would be a liability and legs are not the only option for locomotion. Instead of using legs Cerambycid larvae press fleshy bulges against the walls of their tunnels. [3]

Arguably the most typically eruciform larvae, prolegs and all, are to be found among the butterflies and moths (Lepidoptera), caddis larvae (Trichoptera), and sawflies (Symphyta) [2]

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Beetle Order of insects

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, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 species, is the largest of all orders, constituting almost 40% of described insects and 25% of all known animal life-forms; new species are discovered frequently. The largest of all families, the Curculionidae (weevils), with some 83,000 member species, belongs to this order. Found in almost every habitat except the sea and the polar regions, they interact with their ecosystems in several ways: beetles often feed on plants and fungi, break down animal and plant debris, and eat other invertebrates. Some species are serious agricultural pests, such as the Colorado potato beetle, while others such as Coccinellidae eat aphids, scale insects, thrips, and other plant-sucking insects that damage crops.

Caterpillar Larva of a butterfly or moth

Caterpillars are the larval stage of members of the order Lepidoptera.

Larva Juvenile form of distinct animals before metamorphosis

A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.

Lepidoptera Order of insects including moths and butterflies

Lepidoptera is an order of insects that includes butterflies and moths. About 180,000 species of the Lepidoptera are described, in 126 families and 46 superfamilies, 10 per cent of the total described species of living organisms. It is one of the most widespread and widely recognizable insect orders in the world. The Lepidoptera show many variations of the basic body structure that have evolved to gain advantages in lifestyle and distribution. Recent estimates suggest the order may have more species than earlier thought, and is among the four most speciose orders, along with the Hymenoptera, Diptera, and Coleoptera.

Stridulation is the act of producing sound by rubbing together certain body parts. This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fish, snakes and spiders. The mechanism is typically that of one structure with a well-defined lip, ridge, or nodules being moved across a finely-ridged surface or vice versa, and vibrating as it does so, like the dragging of a phonograph needle across a vinyl record. Sometimes it is the structure bearing the file which resonates to produce the sound, but in other cases it is the structure bearing the scraper, with both variants possible in related groups. Common onomatopoeic words for the sounds produced by stridulation include chirp and chirrup.

Tachinidae Family of insects

The Tachinidae are a large and variable family of true flies within the insect order Diptera, with more than 8,200 known species and many more to be discovered. Over 1300 species have been described in North America alone. Insects in this family commonly are called tachinid flies or simply tachinids. As far as is known, they all are protelean parasitoids, or occasionally parasites, of arthropods, usually other insects. The family is known from many habitats in all zoogeographical regions and is especially diverse in South America.

Geometer moth Family of insects

The geometer moths are moths belonging to the family Geometridae of the insect order Lepidoptera, the moths and butterflies. Their scientific name derives from the Ancient Greek geo γῆ or γαῖα "the earth", and metron μέτρον "measure" in reference to the way their larvae, or "inchworms", appear to "measure the earth" as they move along in a looping fashion. A very large family, it has around 23,000 species of moths described, and over 1400 species from six subfamilies indigenous to North America alone. A well-known member is the peppered moth, Biston betularia, which has been subject of numerous studies in population genetics. Several other geometer moths are notorious pests.

Histeridae Family of beetles

Histeridae is a family of beetles commonly known as clown beetles or Hister beetles. This very diverse group of beetles contains 3,900 species found worldwide. They can be easily identified by their shortened elytra that leaves two of the seven tergites exposed, and their elbowed antennae with clubbed ends. These predatory feeders are most active at night and will fake death if they feel threatened. This family of beetles will occupy almost any kind of niche throughout the world. Hister beetles have proved useful during forensic investigations to help in time of death estimation. Also, certain species are used in the control of livestock pests that infest dung and to control houseflies. Because they are predacious and will even eat other Hister beetles, they must be isolated when collected.

Trogidae Family of beetles

Trogidae, sometimes called hide beetles, is a family of beetles with a distinctive warty or bumpy appearance. Found worldwide, the family includes about 300 species contained in four or five genera.

Dermestidae

Dermestidae are a family of Coleoptera that are commonly referred to as skin beetles. Other common names include larder beetle, hide or leather beetles, carpet beetles, and khapra beetles. There are approximately 500 to 700 species worldwide. They can range in size from 1 to 12 mm. Key characteristics for adults are round oval shaped bodies covered in scales or setae. The usually clubbed antennae fit into deep grooves. The hind femora also fit into recesses of the coxa. Larvae are scarabaeiform and also have setae.

Proleg

A proleg is a small, fleshy, stub structure found on the ventral surface of the abdomen of most larval forms of insects of the order Lepidoptera, though they can also be found on other larval insects such as sawflies and a few other types of insects. In all the orders in which they appear, mainly Hymenoptera and Lepidoptera, prolegs of any form evolved independently of each other by convergent evolution.

Frass Waste from insects

Frass refers loosely to the more or less solid excreta of insects, and to certain other related matter.

Mecoptera Order of insects with markedly different larvae and adults

Mecoptera are an order of insects in the superorder Endopterygota with about six hundred species in nine families worldwide. Mecopterans are sometimes called scorpionflies after their largest family, Panorpidae, in which the males have enlarged genitals that look similar to the stingers of scorpions, and long beaklike rostra. The Bittacidae, or hangingflies, are another prominent family and are known for their elaborate mating rituals, in which females choose mates based on the quality of gift prey offered to them by the males. A smaller group is the snow scorpionflies, family Boreidae, adults of which are sometimes seen walking on snowfields. In contrast, the majority of species in the order inhabit moist environments in tropical locations.

<i>Goliathus</i> Genus of beetles

The Goliath beetles are any of the five species in the genus Goliathus. Goliath beetles are among the largest insects on Earth, if measured in terms of size, bulk and weight. They are members of subfamily Cetoniinae, within the family Scarabaeidae. Goliath beetles can be found in many of Africa's tropical forests, where they feed primarily on tree sap and fruit. Little appears to be known of the larval cycle in the wild, but in captivity, Goliathus beetles have been successfully reared from egg to adult using protein-rich foods such as commercial cat and dog food. Goliath beetles measure from 60–110 millimetres (2.4–4.3 in) for males and 50–80 millimetres (2.0–3.1 in) for females, as adults, and can reach weights of up to 80–100 grams (2.8–3.5 oz) in the larval stage, though the adults are only about half this weight. The females range from a dark brown to silky white, but the males are normally brown/white/black or black/white.

The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments are of Latin origin, and may be confused with terms for bones: coxa, trochanter, femur, tibia, tarsus, ischium, metatarsus, carpus, dactylus, patella.

Glossary of entomology terms List of definitions of terms and concepts commonly used in the study of entomology

This glossary of entomology describes terms used in the formal study of insect species by entomologists.

Limacodidae

The Limacodidae or Eucleidae are a family of moths in the superfamily Zygaenoidea or the Cossoidea; the placement is in dispute. They are often called slug moths because their caterpillars bear a distinct resemblance to slugs. They are also called cup moths because of the shape of their cocoons.

<i>Niphopyralis</i> Genus of moths

Niphopyralis is a genus of snout moths of the subfamily Spilomelinae in the family Crambidae.

External morphology of Lepidoptera

The external morphology of Lepidoptera is the physiological structure of the bodies of insects belonging to the order Lepidoptera, also known as butterflies and moths. Lepidoptera are distinguished from other orders by the presence of scales on the external parts of the body and appendages, especially the wings. Butterflies and moths vary in size from microlepidoptera only a few millimetres long, to a wingspan of many inches such as the Atlas moth. Comprising over 160,000 described species, the Lepidoptera possess variations of the basic body structure which has evolved to gain advantages in adaptation and distribution.

<i>Alsophila pometaria</i> Species of moth

Alsophila pometaria, the fall cankerworm, is a moth of the family Geometridae. The species was first described by Thaddeus William Harris in 1841. It is found in North America from Nova Scotia west to Alberta, south to Colorado and California.

References

  1. Jaeger, Edmund C. (1959). A source-book of biological names and terms . Springfield, Ill: Thomas. ISBN   0-398-06179-3.
  2. 1 2 Imms' General Textbook of Entomology: Volume 1: Structure, Physiology and Development Volume 2: Classification and Biology. Berlin: Springer. 1977. ISBN   0-412-61390-5.
  3. Bannister, Anthony; Skaife, Sally; Ledger, John (1979). African insect life. Feltham: Country Life Books. ISBN   0-600-34920-9.