Tiger Beetles

Carabidae, Cicindelinae. Portuguese:

Tigres velozes (Brazil).

Tiger beetles (Peña 1969, Pearson 1988) are aggressive and efficient predators both as adults and as larvae, hence their common name. They are small to middle-sized beetles (BL 6—40 mm), with a distinctively large head (wider than the prothorax, which is itself much narrower than the rest of the body), conspicuous, bulbous eyes, and scythelike, grossly toothed mandibles. They often have strong patterns and in many instances display very beautiful iridescent green, red, or blue color. Active and agile on long slender legs, they are quick to flee when approached.

Several of the 500 or so Neotropical species are fairly conspicuous, especially the large Pseudoxychila (fig. 9. lj), which are dull, velvety blue-green or blue, with a single, round white or reddish spot in the center of each elytron. They are flightless and diurnal, running on the ground, usually near streams, in a manner similar to that of velvet ant females (Mutillidae), which they apparently mimic. Their biology has been partly elucidated (Palmer 1983).

Megacephala (fig. 9.1h, pi. lg) called caballitos de siete colores in Peru, are also common tiger beetles but are nocturnal and multimetallic colored. Odontocheila (fig. 9.1i) are mostly small (BL 8-10 mm) and dull brown. They are usually seen resting on the upper leaf surfaces of forest understory vegetation during the day (Pearson 1983) between hunting forays to toe ground (Pearson and Anderson 1985).

Males make a mysterious waving display with a foreleg (Palmer 1981), possibly a courtship ritual. Cicindela (fig. 9.1g) are usually marked with contrasting elytral patterns and are common on the open banks of watercourses and lakes or along forest paths and clearings. Ctenostoma are very active and live in the canopy of lowland forests; unlike other cicindelines whose larvae are terrestrial, their larvae develop in rotting logs (Zikán 1929).

Most larval tiger beetles are somewhat wormlike and position themselves head upward in vertical burrows in mud (fig. 9.If), awaiting the approach of other insects and small ground-dwelling invertebrates that they capture by reaching out and grasping them with their mandibles. They have an excessively large head, which, with the prothoracic shield, is held at a right angle to the body to form an effective plug for the burrow mouth. With a hooklike spine on the humped, fifth abdominal segment, the larvae anchor themselves in their tubes and avoid being pulled out by large prey. They leave their burrows at times and creep to new sites, using their legs to drag the long abdomen behind. Adults have also been observed nesting in similar burrows in large numbers (Wille and Michener 1962).

Although commonly treated as a distinct family, tiger beetles are considered a subfamily of Carabidae by modern coleopterists.

References

Palmer, N. 1981. Notes on the biology and behavior of Odontochila mexicana. Cicindela 13(3/4): 29-36. Palmer, M. K. 1983. Pseudoxychila tarsalis (Abejón tigre, tiger beetle). In D. H. Janzen, ed., Costa Rican natural history. Univ. Chicago Press, Chicago. Pp. 765—766. Pearson, D. L. 1983. Patterns of limiting similarity in tropical forest tiger beetles (Coleoptera: Cicindelidae). Biotropica 12: 195-204. Pearson, D. L. 1988. Biology of tiger beetles (Coleoptera: Cicindelidae). Ann. Rev. Ento-mol. 33: 123-147.

Pearson, D. L., and J. J. Anderson. 1985. Perching heights and nocturnal communal roosts of some tiger beetles (Coleoptera: Cicindelidae) in southeastern Peru. Biotro-pica 17: 126-129.

Peña, L. E. 1969. Notes on the Cicindelidae of Chile. Cicindela 1(2): 1-7.

Wille, A., and C. D. Michener. 1962. Inactividad estacional de Megacephala sobrina Dejean (Coleoptera: Cicindelidae). Rev. Biol. Trop. 10: 161-165.

Zikán, J. F. 1929. Zur Biologie der Cicindeliden Brasiliens. Zool. Anz. 82: 269-414.

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