mandible

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Black and white drawing of a grasshopper's head
Mandible of a grasshopper (inscription in English)
black and white drawing of different insect heads in frontal view, mouthparts with identical designations have the same color on all insect heads
Mandibles (shown in green) at
A : grasshopper; B : honey bee;
C : butterfly; D : mosquito.
Mouthparts with mandibles of a cricket .
Mouthparts with shovel-like mandibles of the bee Dianthidium ulkei ( Megachilidae ).

The mandibles are the typical mouthparts of some large groups of arthropods such as crustaceans , insects , centipedes and millipedes .

The mandible consists essentially of a strong chew. The mandibles are used to bite and chew plant and animal food or as a gripping tool when transporting or manipulating objects. Predatory species use their mandibles to catch prey.

Hardness and strength

The mandibles are sometimes heavily stressed mechanically. Sclerotinization and chitin are often not enough to achieve their purpose . A doubling of their hardness (according to Vickers ) compared to the rest of the cuticle due to mineralization , in particular metal deposits, mainly with zinc (Zn) and / or manganese (Mn), in grasshoppers and other insect groups, both in larval stages and in adults , was found.

phylogenesis

Embryonic development

In phylogenesis , the mandibular animals (Mandibulata ) are delimited within the arthropods (Arthropoda) from the jaw-claw carriers (Chelicerata). The mandibular animals include the crustaceans (Crustacea) and the tracheal animals (Tracheata) with the centipedes, millipedes (Myriapoda) and insects. However, there is also the hypothesis that the millipedes are more closely related to the mandibular bearers than to the other mandibular animals. Embryological studies support this hypothesis. However, this raises the question of whether the crustaceans and the tracheal animals acquired the mandibles independently of each other and whether mandible-like mouthparts have emerged several times in the course of evolution. Depending on the intended use and anatomical design, the embryonic development of the mandibles follows two different types of development.

Genetic Studies

Investigations of the Dll ( distal-less ) gene and its gene expression , responsible for mandibular structures, during the embryonic development of millipedes, crustaceans and insects, however, showed great homologies of this gene, which proves a common ancestor of the mandibles.

Precursor forms

The mandibles represent a redesign of the third pair of legs in the head area of ​​their ancestors, who had a chelicerene and five pairs of legs, which consist of seven limbs. The mandibles of the insects are thus homologous to the pedipalps of the arachnids .

Further development

In many insects, the mandibles are transformed into various other types of mouthparts, such as the proboscis of the bugs . Apart from the primeval moths , the mandible of the butterflies is almost completely regressive.

Individual evidence

  1. ↑ Julian FV Vincent, Ulrike GK Wegst: Design and mechanical properties of insect cuticle. In: Arthropod Structure & Development Volume 33, No. 3, July 1, 2004, pp. 187-199, doi: 10.1016 / j.asd.2004.05.006 .
  2. ↑ J. Eric Hillerton, Julian FV Vincent: The specific location of zinc in insect mandibles. (PDF) In: Journal of Experimental Biology 101, No. 1, 1982, pp. 333-336.
  3. ^ Georg Meyer, Paul M. Whitington: Velvet worm development links myriapods with chelicerates. In: Proceedings of the Royal Society. Series B: Biological Sciences. Volume 276, No. 1673, October 22, 2009, pp. 3571-3579, doi : 10.1098 / rspb.2009.0950 .
  4. ↑ SM Manton, JP Harding: Mandibular mechanisms and the evolution of arthropods. In: Philosophical Transactions of the Royal Society, B Biological Sciences 247, No. 737, June 11, 1994, pp. 1-183, doi: 10.1098 / rstb.1964.0001
  5. ↑ G. Scholtz, B. Mittmann, M: Gerberding: The pattern of Distal-less expression in the mouthparts of crustaceans, myriapods and insects: new evidence for a gnathobasic mandible and the common origin of Mandibulata. In: Int. J. Dev. Biol. 42, 1998, pp. 801-810, PMID 9727836 .
  6. ^ Grace Panganiban, Lisa Nagy, Sean B Carroll: The role of the Distal-less gene in the development and evolution of insect limbs. In: Current Biology Vol. 4, No. 8, August 1994, pp. 671-675, doi: 10.1016 / S0960-9822 (00) 00151-2 .
  7. ↑ A. Popadić, Grace Panganiban, Douglas Rusch, William A. Shear, Thomas C. Kaufman: Molecular evidence for the derivation of arthropod gnathobasic mandibles and for the appendicular origin of the labrum and other structures. In: Development Genes and Evolution 208, No. 3, 1998, pp. 142-150.
  8. ↑ Guillaume Lecointre, Hervé Le Guyader: Euarthropoda. In: Biosystematik , Springer, Berlin Heidelberg 2006, Chapter 8, pp. 374-403, doi: 10.1007 / 3-540-29979-3_11 .

Web links

Commons : Mandibles of Insects  - Collection of images, videos and audio files
Wiktionary: Mandible  - explanations of meanings, word origins, synonyms, translations