虎甲亚科亚科

特征

虎甲虫通常有鼓出的大眼睛，长且细的腿和大的弯曲的弯下颌骨。它们的头部很大，驼背利于捕获地面上的昆虫。虎甲属和Tetracha往往色彩鲜艳，别的属通常是统一的黑色。

分布

虎甲属（Cicindela）几乎遍布全球，其他属包括Tetracha、Omus、Amblycheila和Manticora，Manticora属数量最多，主要生活在南非的沙漠。虎甲幼虫生活在1米深的圆柱洞穴。在热带地区的一些虎甲虫是树栖的，但大部分生活在地面上。它们居住在沿海和湖滨，通常在沙丘、黏土堤岸和林地小径，特别喜欢沙地。

习性

成虫和幼虫都是捕食性的。虎甲属昆虫通常是日行性动物，最热的天可能出现，其他属Tetracha、Omus、Amblycheila和Manticora都是夜行性。

行动迅速的成虫反应速度与家蝇相当。这种昆虫生性好斗，速度快。其最快的物种速度可达9公里/小时（5.6英里），相对于其身体长度，相当于人类速度770公里/小时，是前奥林匹克短跑选手迈克尔·约翰逊的22倍。幼虫会在地上挖洞埋伏其内，等猎物走到其洞穴附近时会迅速冲出猎捕。至2005年，约有2,600物种被发现，印度和马来地区分布最广泛，其次为新热带区。

虎甲的成虫由于常在路上人前作短距离飞翔，所以俗称“引路虫”；并已在生物多样性生态研究上应用。

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 9 km/h (5.6 mph; 2.5 m/s), 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 (Indo-Malayan) region, followed by the Neotropics. While historically treated as a subfamily of ground beetles (Carabidae) 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.

In the mid 19th century, Carolus Linnaeus, a Swedish biologist and physician known as the father of modern taxonomy, formally named the first tiger beetle species. Later, field naturalist Thomas Say became the first American to analyze tiger beetles in the field during a period when it was dangerous to conduct field work in America. After decent amounts of data collection, beetle specialists then began to publish articles about tiger beetle taxonomy that was disseminated for other researchers specializing in the research area.

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.

Appearance

Several physical distinctions regarding the tiger beetle include their elongated jaws with teeth on the inner side, general long body shape ranging from 5mm to 4 cm, and thin legs used for running across a variety of surfaces. While many have dulled-black coloration, some species are brightly colored in shades of blue, red, green, purple, and yellow. Most adults have clear wings right on top of their abdomen that generally only permit short-distance flight ranges.

Geographic range

Tiger beetles are distributed based on limitations in resources and desiccation. Tracing fossil data about the species, it's evident that they were alive from about 250 million years ago and are now found throughout regions worldwide with exception to Antarctica. However, they cannot fly far.

There has been an association found between body-size and habitat preferences in a research paper investigating tiger beetles in Sri Lanka.

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.

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.

Taxonomy

Tiger beetles had been treated either as a family Cicindelidae or as the subfamily Cicindelinae of the Carabidae (ground beetles) 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.

General and cited references

Acorn, John (2001). Tiger Beetles of Alberta: Killers on the Clay, Stalkers on the Sand. University of Alberta Press.

Pearson, David L.; Cassola, F. (June 2005). "A Quantitative Analysis of Species Descriptions of Tiger Beetles (Coleoptera Cicindelidae), from 1758 to 2004, and Notes about Related Developments in Biodiversity Studies". The Coleopterists Bulletin. 59 (2).