Omus californicus- California Night-stalking Tiger Beetle




Adults Tiger Beetles are incredibly fast and agile (Spomer et al. 2008), and are commonly the dominant arthropod predators in most ecosystems (Kinsley and Juliano 1988).The genus Omus is one of the least known genera of all Tiger Beetles (Pearson et al. 2005). Carabid beetles, family of Omus californicus form a large taxonomic group. The size of this group exceeds over 40,000 species which are found all throughout the world (Kinsley and Juliano 1988). The only locations these organisms have not been located in Hawaii, Antartica, the Maldives, or Tasmania (Pearson et al. 2005) Between the countless species around the world there are over 100 species found in North America alone (Kinsley and Juliano 1988).

    As a part of the suborder Adephaga, the California Night-stalking Tiger Beetle, has an abdominal pygidial defense gland; these glands produce chemical compounds to ward off predators (Pearson et al. 1988). Although most Tiger Beetles produce a defensive secreation known as benzaldehyde, Omus californicus produces phenylacetic acid to evade predation (Pearson et al. 1988). This is just one of the many evolutionary adaptations that have evolved to better allow Tiger Beetles the greatest chance at survival.

    Another interesting adaptation is that Tiger Beetles have the abitlity to move quickly throughout the environment (Spomer et al. 2008). When chasing prey, these beetles dart and stop in repeated while on the attack, unsual for most predators (Friedlander 1998, Gilbert 1997). During this stop-and-go hunt, Tiger Beetles can reach a maxium speeds of 2.5 seconds per meter which is nearly 125 body lengths of the beetle per second (Friedlander 1998). However, this agility comes at a cost; in pursuit of prey, Tiger Beetles momentarily lose the sense of sight (Friedlander 1998). As explained by Cole Gilbert, professor of entomolgy at Cornell University, when the Tiger Beetle chases prey at high speeds, the beetle cannot gather enough photons to create the image of the prey they are chasing (Friedlander 1998). Overall, the incredibly quick pursuit underminds the beetle's nervous system's ability to process the image motion of hte prey also referred to as reafference (Gilbert 1997).The momentary stop Tiger Beetles take during attacks on prey lasts just long enough for the beetle to relocalize the prey and dash toward the organism (Gilbert 1997).




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