Entomology

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Colored copper engraving by Maria Sibylla Merian from Metamorphosis insectorum surinamensium (1705), plate LX

The Entomology (via "Insect" from Latin insectum "insect", literally "the Incised" of insecare "cut", "nick") or Entomology ( Greek. Ἔντομον entomon "insect", "the Incised" of ἐντέμνειν entémnein " cut in ”) is the branch of zoology that deals with insects ( Insecta ), the most species-rich group of living things . An entomologist is technically known as an entomologist .

Sub-areas

Disciplines that are dedicated to certain groups of animals within insects:

Popular view

The preoccupation with insects originally focused on a few species that are of immediate importance to humans. The most important example is the honey bee , which has been kept as a livestock for thousands of years . Other examples are insects of religious and mythological importance, such as the scarab , which was already depicted in ancient Egypt.

In addition, insects are often viewed with suspicion or ignored, in contrast to mammals and birds . This attitude did not change fundamentally, neither with the beginning of scientific study of insects in antiquity nor with the abundance of new knowledge thanks to the invention of the microscope or the introduction of general science education. Often insects are viewed across the board as pests , superstitious ideas persist, and entomologists are met with reservations. Jean-Henri Fabre found, for example, that simple farmers use precise names even for the most inconspicuous herbs, but only use a few general terms to name the huge number of insects.

On the other hand, it also happens again and again that through attentive observations and vivid descriptions, ignorance turns into curiosity, interest and ultimately even fascination with a previously unknown world. At times, collecting insects, especially butterflies, was a common and popular hobby. Recently, photography , especially macro photography with digital cameras , has given many people access to the world of insects.

History of entomology

Antiquity

The work Historia animalium by Aristotle (384–322 BC) is viewed as the starting point of the occidental systematic preoccupation with the animal world . It represents the first known attempt at a description and classification of living things are made and next to the Naturalis Historia of Pliny the Elder (the 11th book is about the insects in the Leipzig edition Volume 6) to modern times an important basis of scientific work. Aristotle classified the insects as a "genus" and combined them with arachnids, millipedes and worms to form the "bloodless animals". Insects are characterized by a body substance that is something between a hard skeleton and soft flesh. The metamorphosis of the caterpillar to the butterfly was already known to Aristotle, but on the other hand he taught the theory of spontaneous generation, i.e. that insects often arise from inanimate matter, from rotting flesh or in the body of vertebrates. The spontaneous generation remained scientific doctrine for a long time, was at times even considered characteristic of insects and was only experimentally refuted by Francesco Redi ( Esperienze intorno alla generazione degl'insetti , Florence, 1668).

In scientific research into insects, Pliny the Elder (approx. 23–79 AD) was followed by a long pause until Ulisse Aldrovandi , who did not take up the subject again until 1602.

middle Ages

In the Western Middle Ages, natural history was viewed as a branch of philosophy. According to the conviction of Christian science, animate and inanimate nature, as God's creation, was the image of divine will and activity. The focus of the scientists was not on the representation of nature observations, but on the exploration of the will of God, which, according to the general conviction, was revealed even in the smallest and most inconspicuous parts of nature. The Physiologus , an animal book from early Christian antiquity, in which natural history and mythology mix and which was popular in the Middle Ages, should be interpreted in this sense . Insects only play a secondary role, as in Hrabanus Maurus ' De rerum naturis (c. 850), a collection of all knowledge about the universe, and in the later nature encyclopedias by Thomas von Cantimpré ( Liber de natura rerum , 1241) , Albertus Magnus ( De animalibus ), Jacob von Maerlant ( Der naturen bloeme , around 1270) and Konrad von Megenberg ( Book of Nature , 1348). Even if the results of my own observations have increasingly flowed into these works, the lessons to be learned from them are still in the foreground. Thomas von Cantimpré sees the bee state as the model for the ideal human community ( Bonum universale de apibus , around 1260).

16th Century

With the significantly improved dissemination and accessibility of knowledge through the printing press and a more global view of the world through the exploration of foreign regions, science has also changed fundamentally since the beginning of modern times. Natural science was increasingly seen as an independent discipline, research was carried out to gain scientific knowledge and the works of earlier authors were increasingly questioned. The establishment of zoology as an independent science and no longer as part of a philosophical description of the world is generally attributed to Conrad Gessner and his Historia animalium (1551–1558), the sixth volume of which ( Insectorum sive minimorum animalium theatrum ) deals with insects (published posthumously in 1634 in London ). The editors were able to fall back on Ulisse Aldrovandis De animalibus insectis , Bologna 1602, the standard work of entomology of its time, which contained everything that had been written down to date about insects.

17th century

After the first scientific research into the reproduction of insects by Francesco Redi ( Esperienze intorno alla generazione degl'insetti , Florence 1668), the development of entomology is closely linked to the development of the technical possibilities available. In particular, the invention of the microscope made entomology possible for the first time according to today's understanding. While the previous research on insects could only be incomplete, a more precise study of the morphology and an increasingly better differentiation of the species was now possible.

Pioneering discoveries in the field of insect morphology came from the use of the microscope in the 17th century by Marcello Malpighi ( Dissertatio de bombyce , London 1669, a treatise on the silk moth ) and Jan Swammerdam ( Biblia naturae , Amsterdam 1737). For the first time, trachea breathing and the digestive system of insects were examined.

18th century

After the rebuttal of the spontaneous generation theory, the way was free for the formulation of a biological concept of species. This step was taken by John Ray ( Methodus insectorum , London 1705; Historia insectorum , London 1710). The insect species, too, were now regarded as fixed species that had existed unchanged since the creation of the world, and their differences were no longer interpreted as varieties of individual development. With the teaching of the constancy of species, the description of new species and the search for ways to differentiate them began, i.e. systematic entomology. Ray was the first author to have a reasonably realistic view of the abundance of insect species, even if the estimate of 10,000 to 20,000 species worldwide was several orders of magnitude below today's estimates, which is primarily due to the then virtually unknown tropical insect fauna.

Live insect observation was another branch of entomology that had flourished since the 17th century. Important works in this field come from Maria Sibylla Merian ( The caterpillars miraculous transformation and flower food , Nuremberg, 1st volume 1679, 2nd volume 1683; Metamorphosis insectorum surinamensium , Amsterdam 1705), René-Antoine Ferchault de Réaumur ( Mémoires pour servir a l 'histoire des insectes , Paris 1734–1742), August Johann Rösel von Rosenhof ( AJ Rösel's insect amusements , Nuremberg 1746–1755) and above all Carl De Geer ( Mémoires pour servir à l'histoire des insectes , Stockholm 1752–1778; Genera et species insectorum , Leipzig 1783), which are also characterized by the very exact and detailed pictorial representations.

The joker John Hill used the new world of images from the microscopic examinations in his work A decade of curios insects (London 1773) to depict curiously fictitious insects made up of fantastically different individuals - probably to fool his colleagues and test their expertise. Outraged, Johann Christian Fabricius recommended in Systema eleutheratorum (Kiel 1801) to condemn John Hill and his "invented insects": "Damnandae vero memoriae John Hill at Louis Reinhard, qui insecta ficta proposuere" (Preface, page 9).

In the 18th century, science in general experienced a remarkable surge in popularity. Many nobles, now known as scientific pioneers, pursued natural science as a pastime. Princes viewed it as a matter of prestige to support scholars and to be able to present rich natural objects, including collections of insects. In addition, there was an increasing influx of exotic exhibits from all parts of the world. With the Age of Enlightenment, the understanding of science changed again. Religious references were quite common for authors of the 18th century; entomologists interpreted the diversity of species and forms as evidence of God's creative power.

Thus, since Ulisse Aldrovandi ( De animalibus insectis , 1602), the period of apparent nature observation of individual individuals had ended and the number of species had become confusing, so that an attempt was made to regain an overview through suitable systematizations. Carl von Linné distinguished the insects in Systema naturae (Leiden 1735) especially according to their wings. Carl De Geer's attempts to systematize (from 1752) met with rejection and did not last long. Initially, the system was based only on individual external body features (wings, legs, mouthparts) and was always inadequately solved, so that it could be criticized and criticized again and again. With his work Systema entomologiae sistens insectorum classes (Leipzig 1775), Johann Christian Fabricius is regarded as the founder of entomology as an independent science. Its system was based mainly on the mouthparts and lasted for half a century. Overall, the 18th century was a period of rapid development. The systematics of the insects is not yet complete.

19th century

In the works of Jean-Baptiste de Lamarck ( Système des animaux sans vertèbres , Paris 1801; Histoire naturelle des animaux sans vertèbres , Paris 1815–1822), Georges Cuvier ( Tableau élémentaire d'histoire naturelle , Paris 1798; Le règne animal distribué d 'après son organization , Paris 1817–1818) and William Elford Leach ( Familles naturelles du règne animal , Paris 1825; The zoological miscellany , London 1814–1817) the group of insects is largely understood for the first time in the sense that is still valid today separated from arachnids , millipedes and crustaceans .

Despite the demand of the German philosopher Friedrich Wilhelm Joseph Schelling for a holistic view of nature at the turn of the century, a sober, scientific view, mainly focused on evolutionary development and kinship relationships, prevailed in the 19th century, which Hermann Burmeister in his Handbuch der Entomologie (Berlin 1832 –1855) consistently pursued and implemented for the first time. In doing so, he was able to rely on much anatomical preparatory work since the introduction of microscopy into entomology and, in turn, summarized all knowledge of his time critically. Another characteristic of the 19th century after Burmeister is the increasing specialization of research. Systematically working entomologists now mostly only dealt with a single order of insects. In critical revisions, attempts were made to stabilize the species descriptions by earlier authors, to merge synonyms and to describe previously unrecognized species.

In insect morphology, the advanced microscope technology produced many new findings. The extensive work by Léon Dufour ( Recherches anatomiques sur les carabiques et sur plusieurs autres coléoptères , Paris 1824–1826, a milestone in beetle science) is particularly noteworthy in this area . Insect embryology was added as a new research area in the second half of the 19th century .

The work of Charles Darwin had a significant impact . The establishment of a system was no longer solely an orderly character, but had to be measured against the claim to explain the relationships as the result of evolution by comparing all anatomical features.

20th century

Due to technical progress, the focus of biological research shifted in the 20th century. The description and research of individual species, i.e. the classic disciplines of biology, which also includes entomology, will become marginal areas of this science at the end of the century in terms of curricula and research projects at universities. Nevertheless, the biologist Willi Hennig was able to develop the theory of phylogenetic systematics ( cladistics ), which is still recognized today and also used in genetics, through his entomological studies. With his work on evolution and systematics, he revolutionized the view of the natural order of living beings. Since the 1980s, in addition to morphological and anatomical studies, procedural techniques from genetics have also been used in entomology.

Despite the intensive research that has now been carried out in all regions of the world, the identification of the species has not even been completed. The currently around 1.5 million known species are compared to an estimated total of several million.

With the ongoing destruction of natural habitats to this day, however, it can be foreseen that many of today's species will be extinct before they can be scientifically recorded. This is not the only reason why an important trend in 20th century entomology is the increasing focus on the protection of species. Many entomologists nowadays deal with the recording of the species inventory of different biotopes, for example within the framework of intervention regulation or biotope mapping , because the insect fauna plays a key role in the preservation of biodiversity. The concept of biodiversity was particularly coined by the entomologist Edward O. Wilson in 1986.

Insects in nature conservation

Insects react quickly to changes in the landscape. Therefore, the number of insect species found in an area is a good indicator of a landscape's worth of protection. For this purpose, groups of insects are examined that are particularly sensitive to changes - such as butterflies , as they have special demands on food both as caterpillars and as adults.

Entomologist

Catching insects

Glass winged birds on a pheromone trap
After successful scavenging for the purpose of identifying the corrected cicada species

Insects as pests followed in agriculture and as pests hunted by humans. In the past, creating collections of insects was a popular hobby for aesthetic reasons.

In science , the trapping of insects is used to answer numerous basic biological questions. For entomologists insect collections are an important tool: a database for scientific studies (eg fauna, but also genetic), as a reference collection to determine and as storage for types . Insect hunting is mostly selective, and the specimen copies collected by entomologists pose no threat to the local populations. Insects are almost exclusively endangered by the decline in suitable habitats. Nevertheless, the trapping of insects means an intervention in the natural balance and must therefore not be done arbitrarily.

The groups of insects that are particularly, or even strictly, protected under species protection law may only be collected in Germany with special permission from the nature conservation authorities, mostly for scientific purposes. Other insects are allowed to be caught freely, but there are restrictions on the use of automatic catchers, i. H. Traps exposed in the area, such as floor traps or Malais traps, since it cannot be ruled out that protected species may also be caught in them. This is not only for protection, but also for data backup.

Generally, insects are caught with nets ( catchers ), as most of them can fly very quickly and so you can proceed selectively. In addition, numerous other aids are used to catch:

  • Active fishing methods in which the entomologist is actively collecting
    • Cashers
    • Search includes all activities that are carried out on the ground or on vegetation. On the ground, stones or wood are often turned over or decayed wood residues are dismantled and searched with fingers or a tool. Pupae and caterpillars can be found on the vegetation. Digging abandoned mouse or bird nests can also provide information about the parasitic insects that live there.
    • Light catching : Here a black light lamp and a white sheet are set up and at night you wait for insects to appear. This gives the entomologist a good overview of which species are in the catchment area. The species can be counted and individual specimens can be taken. Trapping can be very effective and can attract so many butterflies that they interfere with your work. Light catching at lakes often leads to the accumulation of an extremely large number of mosquitoes, which have to be swept from the cloth with a broom. The light catcher is often used for a sociable nightly get-together in the light of the lamp. Away from power sources, a generator set is often placed out of earshot.
    • Knocking : Knocking is a fishing method in which a stretched white cloth is held under a branch and then the branch is tapped briefly and vigorously with a stick several times. Almost all species that are on this branch fall into the cloth and can be counted. Specific tree species can be searched for by tapping.
    • Car arrestor: Another form of net catching, whereby a cashier is placed on a vehicle. Here, too, there is no selective collection.
    • Exhaustor catch: This catch method uses an exhaustor and one's own breath. In principle, it is suitable for collecting small animals. Beware of smelly animals such as some bed bugs.
    • Baiting : In this method, a bait is applied to trees. At certain intervals a check is made to see which species are present. There are different recipes for preparing the bait. Fruit esters are often added.
  • Passive trapping methods , in which the entomologist sets up a device and waits for the insects to enter on their own.
    • Barber traps : vessels buried in the ground, the edge of which is level with the environment. In particular, animals living on the ground (including vertebrates such as shrews ) are caught . This method is not selective and must be under constant control.
    • Malaise traps
    • Attractant traps : For example, sexual attractants ( insect pheromones ) are used to catch numerous insects . But even a piece of plum cake can attract numerous species of wasps.

Benefit assessment

“Insects are our most important partners in creating life on earth because they often take the lead in designing terrestrial ecosystems . About a third of our food is directly derived from insect pollination . In the US alone, this pollination is worth more than $ 9 billion annually. Without insects there would be no oranges in Florida, no cheese in Wisconsin, no peaches in Georgia, and no potatoes in Idaho. ”
- May R. Berenbaum 2004

Entomology provides important information for numerous other sub-disciplines of biology ( ecology , systematics , taxonomy , genetics , physiology , phylogeny, etc.). Therefore, not only because of the high biodiversity, entomologists are used in almost all disciplines.

literature

Individual evidence

  1. ^ Book of Nature . In: World Digital Library . August 20, 1481. Retrieved August 28, 2013.
  2. ^ Stefan Richter: The teaching collection of the Zoological Institute of the Berlin University ( Memento from April 13, 2012 in the Internet Archive ) Meeting reports of the Society of Friends of Natural Sciences in Berlin Volume 37 (1998), pp. 59–75
  3. ↑ Friedrich von Hartig: About some practical collection methods for biocenotic research in lepidopterology . In: Anzeiger für Schädlingskunde = Journal of Pest Science , Vol. 4 (1928), Issue 5, pp. 67-71, ISSN  1436-5693 .

Web links

Commons : Entomology  - collection of images, videos and audio files
Wikisource: Entomology  - Sources and Full Texts
Wiktionary: entomology  - explanations of meanings, word origins, synonyms, translations