Titan beetle

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Titan beetle
Titanus giganteus MHNT.jpg
Titanus giganteus
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Infraorder: Cucujiformia
Family: Cerambycidae
Subfamily: Prioninae
Tribe: Prionini
Genus: Titanus
Audinet-Serville, 1832
Species:
T. giganteus
Binomial name
Titanus giganteus
(Linnaeus, 1771)
Synonyms

(Genus)

  • PercnopterusGistel, 1848

(Species)

  • Cerambyx giganteusLinnaeus, 1771
  • Prionus giganteus
  • Percnopterus giganteus

The titan beetle (Titanus giganteus) is a Neotropical longhorn beetle, the sole species in the genus Titanus, and one of the largest known beetles.

Contents

Titan beetles are part of the Cerambycidae family, commonly known as the longhorn beetle family, and are the only species in the genus Titanus. Within the Cerambycidae, they are a part of the Prioninae subfamily. These beetles, primarily found in the Amazonian forests of Colombia, Ecuador, Peru, Bolivia, the Guianas, and north-central Brazil, are one of the largest insects in the world, over 170 mm (6.7 in) in length. Titan beetles only live for a few weeks. They defend themselves against predators by using their sharp spines and strong jaws. It is said that their mandibles can snap pencils in half and cut into human flesh.[ copyright violation? ] [1]

Diet

Even though the Cerambycidae family is known to utilize a plant diet for sustenance, the Priorinae subfamily does not accept any food with the exception of water. Reflected in their anatomy, titan beetles do not have all the digestive enzymes and fat reserves needed to consume food on a daily basis. Rather when the titan beetles are larvae, they ingest dead wood and plants infested by fungi. [2] This initial caloric intake is meant to last the lifetime of the beetle. Their dietary habits as larvae contribute to the recycling of dead plants in the ecosystem, converting decayed matter into humus.

The subfamily Priorinae of titan beetles are known as gall-inducing insects. Galls, which are abnormal growths in plants, are a byproduct of plant consumption. These galls are used as nests for many insects, including beetles. [3]

Mating

Because of the short life span of the titan beetle, little is concretely known about their mating behavior. We do know that titan beetles locate their mates by sensing pheromones. [1] In the field of coleopterology the larvae of titan beetles have yet to be found. This makes witnessing the life cycle and reproduction of titan beetles very difficult.

Physiology

Titanus giganteus is known for being one of the largest beetles, spanning over 170 mm (6.7 in). Though great in size, studies have shown that within their Cerambycinae family, they have one of the shortest hind wings. Additionally, the hind wings are not present in females in the Prioninae subfamily the titan beetle is a part of. [2]

The external morphology of the titan beetle is very similar to the morphologies of members of the Prioninae family. Titan beetles have compound eyes (an eye consisting of an array of numerous small visual units), with hundreds of hexagonal facets covering the central region of the eye and the periphery being covered by pentagonal or squares. [4] Titan beetles have exorbitant amounts of facets as there is a correlation between body size and facets in beetles. Smaller beetles and insects have smaller eyes and less facets. These eyes are common across most insects and are present in most types of beetles.

Unique to the Titanus giganteus, there exists a distinct row of proprioceptive hairs that is visible on the anterior edge of the prothorax. The hairs have a mechanoreceptive function, detecting changes to the body surface to assess the environment. [2]

The reproductive system of the titan beetle is very similar to other species within the Priorinae family, with the pupal testis consisting of 12 to 15 lobes each containing 15 follicles. [2] Upon comparison to Lamiinae, a species within the Cerambycidae it was concluded that gametogenesis is terminated at the pupal stage and gonadal degeneration occurs during adult life. One unique characteristic regarding the reproductive anatomy of titan beetles is the variation in follicle size. Titan beetles with larger follicles were seen to have greater rates of spermatogenesis. The mechanism for such variation is unknown.

Size of the Beetle

The titan beetle's ability to grow in size is constrained by the amount of air that can be supplied to its legs and muscles via their circulatory system. [5] The circulatory system of beetles is different from mammals for gas exchange involves tracheal tubes circulating oxygen throughout the beetle's body. The constraining of oxygen in the legs is determined by the space taken up by the tracheal tubes in the exoskeleton of the beetle to allow for proper circulation. One study researching the evolution of gigantic arthropods discovered that during the Carboniferous Period (a period over 300 million years ago in which oxygen levels increased), many organisms had the option of either maintaining or decreasing just their tracheal system relative to their body mass. It was found that species that reduced their tracheal system were able to grow out their exoskeletons to a point before it constrained the tracheal tubes. Hence, the titan beetle likely reduced their tracheal system evolutionarily so as their exoskeleton grew, there was less constriction preventing oxygen from reaching the beetle's legs and muscles.

Microbiome

Because of the unique eating habits (or rather lack of eating habits) of titan beetles, it is interesting to understand the biochemical composition that permits these beetles to sustain life. Research has shown within the very narrow gut of the T. giganteus there is no activity of proteases, despite there being recorded activity of digestive amylase and lipase activity. [2] Digestive amylase, lipase, and protease in human and other animal organisms are responsible for breaking down food proteins into amino acids for bodily absorption. Though not yet tested, it is presumed that because in the second half of the titan beetle's life where there is no purpose to further grow and develop, there is no need for protease activity in the gut. Upon inspection, it was found there was no fat surrounding the gut of T. giganteus, which differed from other organisms within the Prioninae subfamily. It is suggested that the metabolic rate could differ, leading to titan beetles exhausting all of their fat reserves earlier than their sub-family relatives.

The general lipid composition in titan beetles consists mainly of storage lipids. Liquid chromatography-mass spectrometry analysis indicated that 70 percent of the lipids were triacylglycerols. These lipids were found only in the flight muscles, in which the fat reserves were used to provide energy for muscle activity. Within the triacylglycerols, it was found oleic acid is the most abundant. Interestingly enough, the highest levels of oleic acid found were not only in the titan beetles, but also in the locust Locusta migratoria and the blood-sucking bug Panstrongylus megistus.

Distribution

It is known to be found in the rainforests of Venezuela, Colombia, Ecuador, Peru, the Guianas, and north-central Brazil.

See also

Related Research Articles

Digestion is the breakdown of large insoluble food compounds into small water-soluble components so that they can be absorbed into the blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream. Digestion is a form of catabolism that is often divided into two processes based on how food is broken down: mechanical and chemical digestion. The term mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes. Mechanical digestion takes place in the mouth through mastication and in the small intestine through segmentation contractions. In chemical digestion, enzymes break down food into the small compounds that the body can use.

<span class="mw-page-title-main">Hemolymph</span> Body fluid that circulates in the interior of an arthropod body

Hemolymph, or haemolymph, is a fluid, analogous to the blood in vertebrates, that circulates in the interior of the arthropod (invertebrate) body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which hemolymph cells called hemocytes are suspended. In addition to hemocytes, the plasma also contains many chemicals. It is the major tissue type of the open circulatory system characteristic of arthropods. In addition, some non-arthropods such as mollusks possess a hemolymphatic circulatory system.

<span class="mw-page-title-main">Longhorn beetle</span> Family of beetles characterized by long antennae

The longhorn beetles (Cerambycidae), also known as long-horned or longicorns, are a large family of beetles, with over 35,000 species described.

<span class="mw-page-title-main">Digestive enzyme</span> Class of enzymes

Digestive enzymes are a group of enzymes that break down polymeric macromolecules into their smaller building blocks, in order to facilitate their absorption into the cells of the body. Digestive enzymes are found in the digestive tracts of animals and in the tracts of carnivorous plants, where they aid in the digestion of food, as well as inside cells, especially in their lysosomes, where they function to maintain cellular survival. Digestive enzymes of diverse specificities are found in the saliva secreted by the salivary glands, in the secretions of cells lining the stomach, in the pancreatic juice secreted by pancreatic exocrine cells, and in the secretions of cells lining the small and large intestines.

<span class="mw-page-title-main">Lingual lipase</span> Mammalian protein found in Homo sapiens

Lingual lipase is a member of a family of digestive enzymes called triacylglycerol lipases, EC 3.1.1.3, that use the catalytic triad of aspartate, histidine, and serine to hydrolyze medium and long-chain triglycerides into partial glycerides and free fatty acids. The enzyme, released into the mouth along with the saliva, catalyzes the first reaction in the digestion of dietary lipid, with diglycerides being the primary reaction product. However, due to the unique characteristics of lingual lipase, including a pH optimum 4.5–5.4 and its ability to catalyze reactions without bile salts, the lipolytic activity continues through to the stomach. Enzyme release is signaled by autonomic nervous system after ingestion, at which time the serous glands under the circumvallate and foliate lingual papillae on the surface of the tongue secrete lingual lipase to the grooves of the circumvallate and foliate papillae, co-localized with fat taste receptors. The hydrolysis of the dietary fats is essential for fat absorption by the small intestine, as long chain triacylglycerides cannot be absorbed, and as much as 30% of fat is hydrolyzed within 1 to 20 minutes of ingestion by lingual lipase alone.

Lipid metabolism is the synthesis and degradation of lipids in cells, involving the breakdown and storage of fats for energy and the synthesis of structural and functional lipids, such as those involved in the construction of cell membranes. In animals, these fats are obtained from food and are synthesized by the liver. Lipogenesis is the process of synthesizing these fats. The majority of lipids found in the human body from ingesting food are triglycerides and cholesterol. Other types of lipids found in the body are fatty acids and membrane lipids. Lipid metabolism is often considered the digestion and absorption process of dietary fat; however, there are two sources of fats that organisms can use to obtain energy: from consumed dietary fats and from stored fat. Vertebrates use both sources of fat to produce energy for organs such as the heart to function. Since lipids are hydrophobic molecules, they need to be solubilized before their metabolism can begin. Lipid metabolism often begins with hydrolysis, which occurs with the help of various enzymes in the digestive system. Lipid metabolism also occurs in plants, though the processes differ in some ways when compared to animals. The second step after the hydrolysis is the absorption of the fatty acids into the epithelial cells of the intestinal wall. In the epithelial cells, fatty acids are packaged and transported to the rest of the body.

<span class="mw-page-title-main">Hormone-sensitive lipase</span> Enzyme

Hormone-sensitive lipase (EC 3.1.1.79, HSL), also previously known as cholesteryl ester hydrolase (CEH), sometimes referred to as triacylglycerol lipase, is an enzyme that, in humans, is encoded by the LIPE gene, and catalyzes the following reaction:

Insect physiology includes the physiology and biochemistry of insect organ systems.

<i>Macrodontia</i> (beetle) Genus of beetles

Macrodontia is an American genus of long-horned beetles remarkable for their large size and for the large mandibles of the males in particular.

<span class="mw-page-title-main">Spondylidinae</span> Subfamily of beetles

Spondylidinae are a small subfamily of Cerambycidae including slightly over 100 species, primarily in the coniferous forests of the Boreal hemisphere. A few species occur in coniferous forests in tropical and subtropical areas, while very few genera are present in Austral Africa and Madagascar. Some sources spell the name as Spondylinae.

<span class="mw-page-title-main">Disteniidae</span> Family of beetles

The Disteniidae are a small family of beetles in the superfamily Chrysomeloidea, traditionally treated as a group within the Cerambycidae.

Fat globules are individual pieces of intracellular fat in human cell biology. The lipid droplet's function is to store energy for the organism's body and is found in every type of adipocytes. They can consist of a vacuole, droplet of triglyceride, or any other blood lipid, as opposed to fat cells in between other cells in an organ. They contain a hydrophobic core and are encased in a phospholipid monolayer membrane. Due to their hydrophobic nature, lipids and lipid digestive derivatives must be transported in the globular form within the cell, blood, and tissue spaces.

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Desiccation tolerance refers to the ability of an organism to withstand or endure extreme dryness, or drought-like conditions. Plants and animals living in arid or periodically arid environments such as temporary streams or ponds may face the challenge of desiccation, therefore physiological or behavioral adaptations to withstand these periods are necessary to ensure survival. In particular, insects occupy a wide range of ecologically diverse niches and, so, exhibit a variety of strategies to avoid desiccation.

<span class="mw-page-title-main">Insect morphology</span> Description of the physical form of insects

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<span class="mw-page-title-main">Pirinixic acid</span> Chemical compound

Pirinixic acid is a peroxisome proliferator-activated receptor alpha (PPARα) agonist that is under experimental investigation for prevention of severe cardiac dysfunction, cardiomyopathy and heart failure as a result of lipid accumulation within cardiac myocytes. Treatment is primarily aimed at individuals with an adipose triglyceride lipase (ATGL) enzyme deficiency or mutation because of the essential PPAR protein interactions with free fatty acid monomers derived from the ATGL catalyzed lipid oxidation reaction. It was discovered as WY-14,643 in 1974.

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<span class="mw-page-title-main">Diglyceride</span> Type of fat derived from glycerol and two fatty acids

A diglyceride, or diacylglycerol (DAG), is a glyceride consisting of two fatty acid chains covalently bonded to a glycerol molecule through ester linkages. Two possible forms exist, 1,2-diacylglycerols and 1,3-diacylglycerols. Diglycerides are natural components of food fats, though minor in comparison to triglycerides. DAGs can act as surfactants and are commonly used as emulsifiers in processed foods. DAG-enriched oil has been investigated extensively as a fat substitute due to its ability to suppress the accumulation of body fat; with total annual sales of approximately USD 200 million in Japan since its introduction in the late 1990s till 2009.

<span class="mw-page-title-main">Human digestive system</span> Digestive system in humans

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<i>Cacosceles newmannii</i> Species of beetle

Cacosceles newmannii is a species of longhorned beetle in the family Cerambycidae native to Southern Africa. Its natural host plants have not yet been fully determined, but may include species from the family Myrtaceae, and it has started to become a pest of sugarcane crops. It is assumed that its life cycle lasts two years, during which the larvae feed on organic matter.

References

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  2. 1 2 3 4 5 Dvořáček, Jiří; Sehadová, Hana; Weyda, František; Tomčala, Aleš; Hejníková, Markéta; Kodrík, Dalibor (February 2020). "First Comprehensive Study of a Giant among the Insects, Titanus giganteus: Basic Facts from Its Biochemistry, Physiology, and Anatomy". Insects. 11 (2): 120. doi: 10.3390/insects11020120 . ISSN   2075-4450. PMC   7073837 . PMID   32059419.
  3. "Biology, Ecology, and Evolution of Gall-inducing Coleoptera" . Retrieved March 1, 2024.
  4. Makarova, Anastasia A.; Meyer-Rochow, V. Benno; Polilov, Alexey A. (2019-01-01). "Morphology and scaling of compound eyes in the smallest beetles (Coleoptera: Ptiliidae)". Arthropod Structure & Development. Special Issue: Miniaturization in Panarthropoda. 48: 83–97. Bibcode:2019ArtSD..48...83M. doi:10.1016/j.asd.2019.01.001. ISSN   1467-8039. PMID   30625373. S2CID   58572480.
  5. Lighton, John R. B. (2007-11-20). "Respiratory Biology: They Would Be Giants". Current Biology. 17 (22): R969–R971. Bibcode:2007CBio...17.R969L. doi: 10.1016/j.cub.2007.09.019 . ISSN   0960-9822. PMID   18029253.