The Ohlone tiger beetle is a diurnal predatory beetle in the tiger beetle subfamily. This species was only recently discovered and described in the early 1990s. Initially thought to be a variant of a subspecies of Cow Path tiger beetle, the Ohlone tiger beetle was recognized as a separate species due to differences in genitaland seasonal activity. Endemic to California, this small beetle is found only in Santa Cruz County. Federally listed as endangered in 2001, this species greatest threats are urban development and habitat degradation. Scientists are working to prevent the extinction of this small beetle by enhancing its habitat by removing and reintroducing adult beetles where they historically occurred.
The Ohlone tiger beetle is only found in grassland habitats on coastal terrace prairies. Coastal terrace prairies are communities characterized by the presence of purple needlegrass and California oatgrass , as well as shallow soil that becomes hard in the summer and softens during the winter rains. Adult beetles will use grassland areas that have little to no vegetation for larval burrowing and thermoregulation (behavior used to regulate body temperature using the sun or shade). This species is often found on level or near level ground near grassland habitat, meaning they are often located close to footpaths and bike trails. If you are recreating in Ohlone tiger beetle habitat from January to May, keep bike speeds below 5 mph to avoid crushing this species.
Land on which the natural dominant plant forms are grasses and forbs.
The land near a shore.
The Ohlone tiger beetle preys on small arthropods such as spiders and ants. Both adults and larvae are carnivorous and will prey upon other insects.
The hunting behaviors of the Ohlone tiger beetle are similar to other tiger beetles, wherein both adult and larvae are carnivorous. Adults will hunt by running in short bursts, occasionally stopping to look for prey; they have to stop periodically as they run so fast they cannot see their prey while moving. Once they have spotted their prey, they will run it down and grab the prey with their long mandibles. These mandibles are also used to chew their prey into a puree, and the enzymes that are released during will begin digestion. The hunting behavior of larvae differs from adults, as adults will actively pursue their prey while larvae will wait and ambush their prey. Larvae will lie in wait, positioning themselves at the top of their burrow; when prey comes near, the larvae will extend themselves and grab the prey with their mandibles. The larvae will then pull the prey into its burrow to consume. These burrows serve a purpose beyond hunting; when presented with possible danger, the larvae will draw back into their burrow immediately.
The Ohlone tiger beetle is relatively small for its genus. Other species in the genus are larger in size and have bigger elytra (tough forewings used to protect the hind wings). However, the Ohlone tiger beetle is smaller with proportionately smaller elytra. They have large eyes and long slender legs.
Length: 9.5 mm to 12.5 mm (0.37 in to 0.49 in)
Adults of the species are a grassy green color with subtle bronze accents on their thorax. Their forewings are bright green, and their legs are coppery-green. Larvae of the Ohlone tiger beetle are similar to other tiger beetle larvae. The larvae are grub-like and are either yellowish or white.
As larvae, tiger beetles will undergo three stages of larval development. After mating, a female tiger beetle will dig a hole into the ground and lay an egg into it. It is unknown how many eggs female Ohlone tiger beetles lay, but other members of its genus can lay between 1 and 126 eggs. A larvae will emerge from the egg and harden; it will then widen the hole it was laid in until it becomes a burrow. During the last larval development stage, the larvae will close off the entrance of its burrow and dig a chamber. In this chamber, the larvae will complete the transformation from larvae to adult. After transforming into an adult, the beetle will emerge from the ground, and it can either immediately begin reproduction or can delay when reproduction occurs. This species has a winter seasonality, where adults will emerge and be active in winter instead of the spring and fall, which is common for other tiger beetles. This seasonality is due to the climate and geology of Santa Cruz County. During the dry season, the soil within Ohlone tiger beetle habitat will become extremely hard, making it impossible for females to lay eggs in the soil and for larvae to dig burrows. However, by being active in the winter, the species can avoid this problem, because during the wet winter months, the heavy rainfall makes the soil ideal for egg deposition.
The Ohlone tiger beetle has similar mating behaviors to other tiger beetles. To begin reproduction, a male will pursue a female by running in short bursts. When the male is close enough, he will jump on the female's back. The female will attempt to buck him off, and only the successful males who are able to stay on will be able to fertilize the female’s eggs. After mating, the male sometimes continues to stay on the female's back to guard the female, preventing other males from fertilizing her eggs. After fertilization, the female will deposit her eggs into the soil, and if conditions are right, the eggs will hatch in about two weeks.
The Ohlone tiger beetle has a lifespan of one to two years.
The Ohlone tiger beetle is most similar to Cicindela purpurea lauta, a subspecies of the Cow Path tiger beetle. Both species are a grassy green color, and both have bronze accents on their thorax. C. purpurea lauta occurs in northwestern California; however, it does not overlap with the Ohlone tiger beetle as no other species of tiger beetle occurs in Ohlone tiger beetle habitat. Despite having many similarities, the Ohlone tiger beetle was recognized as a separate species due to their differences in genitalia and seasonality.
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