Tiger beetle


Tiger beetles or the Cicindelidae are a family of beetles known for their aggressive predatory habits and running speed. The fastest known species of tiger beetle, Rivacindela hudsoni, can run at a speed of, or about 125 body lengths per second. As of 2005, about 2,600 species and subspecies were known, with the richest diversity in the Oriental region, followed by the Neotropics. While historically treated as a subfamily of ground beetles under the name Cicindelinae, several studies since 2020 indicated that they should be treated as a family, the Cicindelidae, a sister group to Carabidae, within the Adephaga.

Description

Well-known genera include Cicindela, Tetracha, Omus, Amblycheila and Manticora. Cicindela has a cosmopolitan distribution.
Many tiger beetles have large bulging eyes, long slender legs and large curved mandibles. Both Cicindela and Tetracha are often brightly colored, while the other genera mentioned are usually uniform black in color. Tiger beetles in the genus Manticora, which live primarily in the dry regions of southern Africa, are the largest in size.
While members of the genus Cicindela are usually diurnal and may be out on the hottest days, Tetracha, Omus, Amblycheila and Manticora are all nocturnal. All tiger beetles are predatory, both as adults and as larvae. They prey on nearly anything they can catch, including other beetles, hoppers, ants and caterpillars.
The larvae of tiger beetles live in cylindrical burrows as much as a meter deep. The grubs have a large head with a pair of formidable mandibles. They have six simple eyes on each side of the head. Two pairs are much larger than the others, and seem to be used for range estimation. The largest have about 5000 retinal cells. There is a prominent hump on the top of their fifth abdominal segment with two pairs of reverse pointing hooks to anchor them in their burrow with their head filling the entrance and flush with the surface.
The larvae wait for prey to come close enough, attempt to grab and pull them down their shaft. The hump and hooks prevent struggling prey from pulling them out of their shaft.
The fast-moving adults run down their prey and are extremely fast on the wing, their reaction times being of the same order as that of common houseflies. Some tiger beetles in the tropics are arboreal, but most run on the surface of the ground. They live along sea and lake shores, on sand dunes, around playa lakebeds and on clay banks or woodland paths, being particularly fond of sandy surfaces.
Tiger beetles are considered a good indicator species and have been used in ecological studies on biodiversity. Several species of wingless parasitic wasps in the genus Methocha lay their eggs on larvae of various Cicindela species, such as Cicindela dorsalis.

Adaptations

Tiger beetles have an unusual form of pursuit in which they alternately sprint toward their prey, then stop and visually reorient. This may be because the beetle runs too fast for its visual system to accurately process images. To avoid obstacles while running they hold their antennae rigidly and directly in front of them to mechanically sense their environment. Many tiger beetles hunt in flat sandy areas, and their eyes have flat-world adaptations, such as high-acuity perception streaks corresponding to the horizon. A tiger beetle uses the elevation of its potential prey in its visual field to determine how far away it is. As visual hunters, tiger beetles tend to hunt in open, relatively flat habitats, such as sand bars, woodland paths, and barren ground scrubland. In this sense, beetles might be expected to use elevation as a distance cue in their visual pursuit of prey. A few species of Cicindela are able to hunt without using their eyes and several are crepuscular.
Several species are known to be sensitive to ultrasound and produce ultrasound in response to bats, and are thought to be Batesian mimics, imitating the sounds of toxic moths that are avoided by bats.

Fossil record

The oldest fossil tiger beetle yet found, Cretotetracha grandis, comes from the Yixian Formation in Inner Mongolia, China, and dates to the early Cretaceous Period, 125 million years ago. Most fossils found are grey or yellow silty mudstone. Traits that identify Cretotetracha as Cicindelinae include long mandibles shaped like sickles, simple teeth arranged along the mandible's inner surface, antennae that attach to the head between the base of the mandibles and the eye. The left mandible is approximately 3.3 mm and the right mandible is approximately 4.2 mm long. A long body form roughly around 8.1 mm where the combined eyes and head are wider than the thorax, and long running legs. Previously known Mesozoic fossils of tiger beetles have been described from the Crato Formation, about 113 million years ago and Oxycheilopsis cretacicus from the Santana Formation, 112 million years ago, both in Brazil.

Taxonomy

Tiger beetles had been treated either as a family Cicindelidae or as the subfamily Cicindelinae of the Carabidae but since 2020, there has been growing evidence for the treatment as a separate family, that is sister to the Carabidae. Many genera are the result of the splitting of the large genus Cicindela, and many were described by the German entomologist Walther Horn.

Genera

Abroscelis Hope, 1838 Amblycheila Say, 1829 Aniara Hope, 1838 Antennaria Dokhtouroff, 1883 Apteroessa Hope, 1838 Archidela Rivalier, 1963 Bennigsenium W. Horn, 1897 Brasiella Rivalier, 1954 Caledonica Chaudoir, 1860 Caledonomorpha W. Horn, 1897 Callidema Guerin-Meneville, 1843Callytron Gistl, 1848 Calomera Motschulsky, 1862Calyptoglossa Jeannel, 1946 Cenothyla Rivalier, 1969 Cephalota Dokhtouroff, 1883Chaetodera Jeannel, 1946 Cheilonycha Lacordaire, 1843 Cheiloxya Guerin-Meneville, 1855 Cicindela Linnaeus, 1758Collyris Fabricius, 1801 Cratohaerea Chaudoir, 1850 Cretotetracha Zhao et al., 2019Ctenostoma Klug, 1821 Cylindera Westwood, 1831Darlingtonica Cassola, 1986 Derocrania Chaudoir, 1860Diastrophella Rivalier, 1957 Dilatotarsa Dokhtouroff, 1882 Distipsidera Westwood, 1837Dromica Dejean, 1826Dromicoida Werner, 1995 Dromochorus Guerin-Meneville, 1845 Ellipsoptera Dokhtouroff, 1883Enantiola Rivalier, 1961Eunota Rivalier, 1954 Euprosopus Dejean, 1825 Euryarthron Guerin-Meneville, 1849Eurymorpha Hope, 1838Euzona Rivalier, 1963 Grammognatha Motschulsky, 1850Grandopronotalia W. Horn, 1936 Guineica Rivalier, 1963 Habrodera Motschulsky, 1862Habroscelimorpha Dokhtouroff, 1883 Heptodonta Hope, 1838 Hypaetha Leconte, 1860 Hujia Iresia Dejean, 1831Jansenia Chaudoir, 1865 Jundlandia Langea W. Horn, 1901 Leptognatha Rivalier, 1963Lophyra Motschulsky, 1859Macfarlandia Sumlin, 1981 Manautea Deuve, 2006 Mantica Kolbe, 1896Manticora Fabricius, 1781Megacephala Latreille, 1802Megalomma Westwood, 1842 Metriocheila Thomson, 1857Micromentignatha Sumlin, 1981 Microthylax Rivalier, 1954 Myriochila Motschulsky, 1862Naviauxella Cassola, 1988 Neochila Basilewsky, 1953 Neocicindela Rivalier, 1963 Neocollyris W. Horn, 1901Neolaphyra Bedel, 1895 Nickerlea W. Horn, 1899 Notospira Rivalier, 1961 Odontocheila Laporte, 1834Omus Eschscholtz, 1829 Opilidia Rivalier, 1954 Opisthencentrus W. Horn, 1893 Orthocindela Rivalier, 1972 Oxycheila Dejean, 1825

General and cited references

  • Acorn, John. Tiger Beetles of Alberta: Killers on the Clay, Stalkers on the Sand. University of Alberta Press.
  • Pearson, David L.; Cassola, F.. "A Quantitative Analysis of Species Descriptions of Tiger Beetles, from 1758 to 2004, and Notes about Related Developments in Biodiversity Studies". The Coleopterists Bulletin. 59.
  • Pearson, David L.; Knisley, C. Barry; Kazilek, Charles J.. A Field Guide to the Tiger Beetles of the United States and Canada. Oxford University Press.
  • Pearson, David L.; Vogler, Alfried P.. Tiger Beetles: The Evolution, Ecology, and Diversity of the Cicindelids. Cornell University Press.
  • Schüle, Peter. "Further new country records of African Tiger Beetles with some taxonomical note ". Entomologia Africana 15.
  • Werner, Karl. The Beetles of the World, , , , and 20 , Sciences Nat, Venette.
  • Werner, Karl. The Tiger Beetles of Africa. Taita Publishers.