Cicadas

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Cicadas
Cicadella viridis (Cicadella viridis)

Cicadella viridis ( Cicadella viridis )

Systematics
Trunk : Arthropod (arthropoda)
Class : Insects (Insecta)
Subclass : Flying insects (Pterygota)
Order : Schnabelkerfe (Hemiptera)
Subordination : Cicadas
Scientific name
Auchenorrhyncha
Duméril , 1806
Larva of cicadella viridis ( Cicadella viridis )

The cicadas (from Latin cicada ; Auchenorrhyncha = Cicadina ), also chirps , are insects that suckle on plants and as such belong to the Schnabelkerfen (Hemiptera). The cicadas include the suborders of the round head cicadas (Cicadomorpha) and the pointed head cicadas (Fulgoromorpha). Well over 45,000 species have been described worldwide.

Size and shape

Well camouflaged singing cicada (Cicadidae) on tree bark: Manna cicada ( Cicada orni ), Croatia
A humpback sirp ( Membracidae): thorn cicada ( Centrotus cornutus )

Leafhoppers are characterized by a roof-shaped wing attitude, the two Basalgliedern and a filamentary scourge existing sensors and the springing on the lower edge of the head proboscis marked. The front wings of the cicadas are not hardened like those of the bedbugs , although they are much coarser than the hind wings. The body length of the animals is between 1.8 and 38 millimeters. The imperial cicada ( Pomponia imperatoria ) can be up to 70 millimeters long and have a wingspan of a maximum of 180 millimeters. Some species of the subfamily of leaf cicadas ( Typhlocybinae ) and some spur leaf hoppers ( Delphacidae ) do not even reach 2 millimeters in length.

Most of the cicadas are very noticeably colored, but still specialists in camouflage . In their living spaces, they are usually perfectly adapted to their surroundings thanks to their color scheme. Some species have high-contrast patterns that dissolve the body outline. This means that predators can hardly recognize them. The hind legs are transformed into jump legs, which gives most cicadas very good jumping properties. Because of their jumping ability, cicadas are often mistaken for grasshoppers , but they are not related to them. Species of the humpback chirp family have particularly bizarre shapes due to different, sometimes very complex and expansive appendages of the pronotum .

All cicadas have a proboscis for feeding. The lower lip labium of the animals is designed as a sliding rail for the spines consisting of the mandibles and maxillae. Inside the laciniae (part of the maxilla) there is a channel through which suction can take place, as well as a saliva channel through which saliva is conducted into the feeding site. In all Schnabelkerfen parts of the oral cavity are transformed into a suction pump.

Way of life

nutrition

The cicadas are fed by piercing and sucking out certain parts of the plant, as it were with a straw. You are dependent on food that is already liquid. Most species specifically suck on the lines of the plants with sugar-rich juice ( phloem ). In doing so, however, they absorb significantly more sugar than they can utilize. The excess sugar is excreted. The so-called honeydew is often ingested by other insects. For example, many ant cicadas (Tettigometridae) and humpback cicadas (Membracidae, e.g. the gorse cicada Gargara genistae ) live in close association with ants. The xylem sap (water and mineral salts) or leaf cells are also used as food resources.

Most species of cicada are restricted to very specific nutrient plants. In most cases the reasons for this are still unclear. The spectrum of plant species used ranges from strict monophagy to oligophagy and polyphagia : monophagous species only use one plant species (monophag 1st degree) or one plant genus (monophag 2nd degree) as the host plant. Oligophagous cicadas only use one plant family (oligophagous 1st degree) or a maximum of two plant families or four plant genera from a maximum of four families (oligophagous 2nd degree). Polyphage cicadas are not very picky about their food and use several plant genera or families. The grouping is still uncertain for a number of species of cicada. The Fulgoromorpha mainly use grasses as food resources , the Cicadomorpha mainly herbs and deciduous trees; a few species also use fungal mycelia , ferns and conifers.

Locomotion and expansion

The most common mode of locomotion of the cicadas is running, but the most distinctive is jumping. Cicadas have specially trained hind legs. Foam cicadas are the world champions in high jump. The researcher Malcolm Burrows discovered this on high-speed photos. In relation to its own body length, no living being can jump as high as the foam cicada. The insect is half a centimeter long and reaches a height of 70 centimeters from a standing position. The foam cicada, like every insect, has three pairs of legs; Only the rearmost pair provides jump energy. The animal can build tension in these legs like in a catapult and then discharge it.

Larger distances are either covered passively by drifting through the wind - with usually no directional propagation - or actively overcome by flying. Most species are able to fly, provided they are long-winged individuals. A wing dimorphism can be observed in many species of cicada . Long-winged ( macroptere ) and short-winged ( brachyptere ) forms can be found within a species, often even within a population. The short-winged animals are unable to fly. Obviously, the environmental quality in larval development is used to decide whether flightable (good nutrient plant quality, low population density) or flightless animals (low nutrient plant quality, high population density) arise.

Reproduction and development

Rhododendron leaf hoppers mating
Freshly hatched adult meadow foam cicada ( Philaenus spumarius ) leaves its foam nest to dry and fly away.
A hatching cicada in fast motion

Cicadas reproduce bisexual, i. H. an egg must be fertilized in order to develop. The eggs are usually elongated oval and surrounded by an egg shell ( chorion ), which have penetration points for the sperm at certain points. The fertilized eggs are partly laid in the ground, partly on or in plants. Cicadas undergo an incomplete transformation from the egg via the larva directly (without the pupal stage) to the full insect ( imago ); they are hemimetabolic . The development usually takes place over five larval stages , whereby the duration can be different for the different species. Some species have one, others two or three generations a year. For some species, the number of generations also depends on the climate. For example, the spur-leaf cicada Nilaparvata lugens has three generations a year in Japan, and up to twelve generations in warmer Southeast Asia; other species take years. In the USA, for example, there live song cicadas of the genus Magicicada , which only mate every 13 or 17 years.

The meadow foam cicada ( Philaenus spumarius ) and its relatives produce what is known as cuckoo saliva . The larvae hatched from the eggs laid in the previous year produce the “saliva” themselves. These are foam bubbles that are created by blowing air into the protein-containing excrement of the larvae. The foam protects the larvae sitting in it from enemies and maintains the moisture and temperature necessary for further development.

Sound production and senses

Head of a singing cicada, clearly visible the compound eyes and antennae
Mannazicade ( Cicada orni ) on a pine trunk and its song ? / iAudio file / audio sample
Lures and deterrents of a southern European head cicada

Although all species of cicada emit sound or vibration waves for communication, only the singing cicadas are able to produce sounds that can be heard by humans. For this they have their own organ, the "drum organ" ( tymbal ) at the beginning of the abdomen. By attaching muscles (sing muscles), records are made to vibrate in this organ. The organ is covered by a cover that extends from the last breast segment, and often also by a plate on the organ itself. A large air sac provides the necessary resonance directly under the singing muscle . With the help of these organs, sounds in the range from 0.5 to 25 kilohertz can be generated. The singing of the males serves primarily to attract the females, but it is also used to establish territorial boundaries .

With the other cicadas, the perception of acoustic stimuli via the medium of air plays a less important role. Rather, they are equipped with receptors all over the body in order to perceive air currents, contact with other living beings or the parts of plants on which they sit. The vibrations transmitted from the drum organs to parts of plants are probably absorbed in this way as so-called substrate vibrations. The orientation of the cicadas occurs through the absorption of environmental stimuli. Your compound eyes are able to recognize and differentiate shapes as well as colors. This enables them to notice pursuers, but also to target plants. They even seem to recognize the color of their nutrient plants and also to be able to judge the seat for hiding uniformity. In addition, cicadas have so-called mechano -receptors in almost all parts of the body for the perception of touch stimuli such as air currents, contact with the substrate and others.

Butterfly cicada (Flatidae): Metcalfa pruinosa

Habitats

Cicadas live around the world in all terrestrial , plant-based habitats, from the salt marshes of the North and Baltic Seas, through the high mountains to the tropics and subtropics . They colonize all habitats from the bank of water to dry grassland and forests . In addition to the occurrence of the corresponding host plant (s), other environmental conditions such as the microclimate and the vegetation structure are decisive for the distribution of species in space and time.

Enemies and parasites

Cicada larva with "dryinid sack".

The main enemies of the cicadas are spiders, predatory bugs, some soft bugs, ants and birds. Several parasites and parasitoids are found in adult cicadas and larvae: dryinidae ( Hymenoptera , Dryinidae ) Embolemidae (Hymenoptera), eyed flies ( Diptera , Pipunculidae ) and Fächerflügler (Strepsiptera). Cicadas infested by cicada wasps can be recognized by a protuberance, the “dryinid sack”, which protrude on the body between the segments of the abdomen and contain the dryinid larvae. The larvae of the eye flies and the fan-winged, on the other hand, develop within the body of the cicadas. The infestation of the cicadas by the various parasites can lead to major changes in the genital structures. Furthermore, the eggs of cicadas can be parasitized by parasitic wasps (Hymenoptera, Trichogrammatidae and Mymaridae).

Significance and danger

The herbivorous insects make up around a quarter of all organisms with around 350,000 species . The first-order consumers take on an important position in the structure of the natural balance. As a group of insects that is rich in individuals, the cicadas not only influence the composition and dynamics of the vegetation, but also play an important role in the formation of complex food webs as food for other animals . This shows the special importance of phytophagous insects and thus also of the cicadas with regard to the functionality of biotopes and entire ecosystems . The abundance of species of the cicadas, the colonization of almost all terrestrial habitats, the often very close connection of many species to certain habitats and host plants as well as the diverse demands on the location conditions in their habitat make them particularly interesting for ecological questions such as the condition of their habitat. Cicadas in particular often have a pronounced spatial and temporal sensitivity, which means that they react relatively quickly and in small areas to changes in their habitat . Because of these properties, cicadas are particularly suitable as so-called pointer animals or bioindicators in nature and landscape planning . The proportion of cicada species recorded in the nationwide Red List of Endangered Species is over 50 percent. In Germany 56 species are threatened with extinction. The population density of many species of cicada has also declined over the past few decades. The main reasons for the loss of species and individuals are: Habitat destruction, intensive agriculture and forestry, changes in historical forms of use and interventions in the water balance.

Systematics

Different species of cicada during the determination

Cicadas (Auchenorrhyncha = Cicadina) comprise two large groups, the pointed head cicadas (Fulgoromorpha = Archaeorrhyncha) and the round head cicadas (Cicadomorpha = Clypeorrhyncha). The monophyly of the auchenorrhyncha has been questioned in some studies. In the new work by Cryan and Urban (2012), however , the monophyly was confirmed again. In any case, the old name Homoptera for cicadas and plant lice is obsolete because they are not related to a family.

The Hemiptera are divided as follows:

  • Plant lice (Sternorrhyncha)
  • Cicadas (Auchenorrhyncha)
  • Prosorrhyncha or Heteropterodea

The Sternorrhyncha are the sister group of a taxon Auchenorrhyncha / Heteropterodea. Within the Heteropterodea, Heteroptera and Coleorrhyncha are sister groups.

Submissions

Pointed-head cicadas - Fulgoromorpha (Fulgoriformes)

The basic construction plan of the Fulgoromorpha

Pointed-head cicadas , also called lantern-bearers, differ from the round-headed cicadas in the shape of the antennae and the rear hips, which are fused with the breast segments. The most prominent representatives of this group are the lantern bearers of the genus Fulgora, native to South America, with a conspicuous lengthening of the forehead. Fulgora laternaria is best known in Europe for the drawings by Maria Sibylla Merian . It was mistakenly assumed that the hollow head extension glowed, hence the name. More than 12,900 species have been described worldwide, assigned to 17 to 21 recent families. All of these families belong to the only recent superfamily Fulguroidea. The Coleoscytoidea and the Surijokocixioidea are two other superfamilies whose members are only known from fossils. In Central Europe there are representatives from a total of 10 families.

Families, subfamilies and selected species in Central Europe:

Round-headed leafhoppers - Cicadomorpha (Cicadiiformes)

The basic plan of the Cicadomorpha

The round-headed cicadas represent the largest group of cicadas. Around 35,000 species have been described around the world and are assigned to 11 to 12 recent families. These families are divided into three superfamilies: Membracoidea, Cicadoidea and Cercopoidea. In Europe there are 10 families with approx. 1344 species in 283 genera, of which 673 species in 203 genera from 5 families occur in Central Europe and in Germany there are 5 families with 475 species in 166 genera.

Families, subfamilies and selected species in Central Europe:

Literature and Sources

Beginning of moult
  • R. Biedermann, R. Niedringhaus: The cicadas of Germany - identification tables for all kinds . Fründ, Scheeßel, 2004, ISBN 3-00-012806-9 .
  • WE Holzinger, I. Kammerlander, H. Nickel: The Auchenorrhyncha of Central Europe - Die Zikaden Mitteleuropas. Volume 1: Fulgoromorpha, Cicadomorpha excl. Cicadellidae. - Leiden: Brill, 2003, ISBN 90-04-12895-6 .
  • G. Kunz, H. Nickel, R. Niedringhaus: Photo atlas of the cicadas in Germany . - Fründ, 2011, ISBN 978-3-939202-02-8 .
  • H. Nickel: The leafhoppers and planthoppers of Germany (Hemiptera, Auchenorrhyncha): Patterns and strategies in a highly diverse group of phytophagous insects . - Sofia and Moscow: Pensoft, 2003, ISBN 954-642-169-3 .
  • H. Nickel, WE Holzinger, E. Wachmann : Central European habitats and their cicadas (Insecta: Hemiptera: Auchenorrhyncha) . - Denisia 4, 2002, pp. 279-328.
  • H. Nickel, R. Remane : List of species of cicadas in Germany, with information on nutrient plants, food breadth, life cycle, area and endangerment (Hemiptera, Fulgoromorpha et Cicadomorpha) . - Contributions to the cicada 5, 2002, pp. 27–64. pdf 229 KB
  • R. Remane, E. Wachmann: Cicadas - get to know, observe . - Augsburg: Naturbuch, 1993, ISBN 3-89440-044-7 .
  • Malcolm Burrows: Froghopper insects leap to new heights . - Nature 424, 2003, p. 509.

Web links

Commons : Cicadas  - Collection of images, videos and audio files

Individual evidence

  1. ↑ a b Hans Strümpel: The cicadas . You Neue Brehm Bücherei 668, Hohenwarsleben 2010, ISBN 978-3-89432-893-1 , p. 161 .
  2. ^ S. Schuch, K. Wesche, M. Schaefer (2012) Long-term decline in the abundance of leafhoppers and planthoppers (Auchenorrhyncha) in Central European protected dry grasslands. Biological Conservation 149 : 75-83.
  3. ↑ a b Cryan, Jason R. & Julie M. Urban (2012): Higher-level phylogeny of the insect order Hemiptera: is Auchenorrhyncha really paraphyletic? Systematic Entomology, 37: 7-21. doi: 10.1111 / j.1365-3113.2011.00611.x
  4. ↑ FLOW (Fulgoromorpha Lists on The Web): a world knowledge base dedicated to Fulgoromorpha. Bourgoin, Th., Accessed March 2, 2015 .
  5. ^ N. Song, AP. Liang: A Preliminary Molecular Phylogeny of Planthoppers (Hemiptera: Fulgoroidea) Based on Nuclear and Mitochondrial DNA Sequences. In: PLoS ONE . tape 8 , no. 3 , 2013, p. e58400 , doi : 10.1371 / journal.pone.0058400 .
  6. ↑ Eddy Dijkstra, Jose M. Rubio, Rory J. Post: Resolving relationships over a wide taxonomic range in Delphacidae (Homoptera) using the COI gene , in: Phylogenomics, February 9, 2003, doi: 10.1046 / j.1365-3113.2003. 00203.x
  7. ↑ Cicadomorpha in Fauna Europaea , as of March 2, 2015.
  8. ↑ WE Holzinger et al. (1997): Preliminary list of cicadas from Central Europe (Insecta: Auchenorrhyncha). Contributions to cicada lore 1: 43-62. ( PDF, 122 kB ), accessed on August 31, 2016
  9. ↑ Herbert Nickel and Reinhard Remane: List of species of cicadas in Germany, with information on nutrient plants, food breadth, life cycle, area and endangerment (Hemiptera, Fulgoromorpha et Cicadomorpha). Contributions to the cicada, 5, 2002, pp. 27–64 full text (PDF, German; 234 kB)