Rare Species Guide

  Basis for Listing

The crimson saltflat tiger beetle (fulgida subspecies) was first observed in Minnesota in 1967 on the north shore of Salt Lake in Lac Qui Parle County. The colony was verified in 1968-1970, but it may now be extirpated, as the water levels at this site have been very high for a number of years. An observation of this site in the summer of 2003 revealed minimal exposed shoreline and no red saltwort (Salicornia rubra), which is an indicator plant for this subspecies. There are no other localities of this subspecies known in the state. Given its restricted range and the vulnerability of its habitat, the crimson saltflat tiger beetle (fulgida subspecies) was listed as an endangered species in Minnesota in 1996.

  Description

Adult crimson saltflat tiger beetles (fulgida subspecies) are small, averaging 10-11 mm (0.39-0.43 in.) long, and are bright metallic red with 3 well-separated lunulate ivory markings on each wing cover. Older individuals may be a darker shade of red, resembling the westbournei subspecies.

Tiger beetle larvae are mostly white and somewhat grub-like (Pearson et al. 2006). The portions of their bodies that are exposed in their burrow entrances are usually the same color and texture as the surrounding soil surface, allowing them to blend in with the soil (Pearson et al. 2006; R. Dana, Minnesota DNR, pers. comm.). Tiger beetle larvae have eyes with dense photoreceptors that give them detailed focusing ability and three-dimensional visual perception (Pearson et al. 2006).

  Habitat

The crimson saltflat tiger beetle (fulgida subspecies) is found in open, sparsely vegetated, moist saltflats with salt grass (Distichlis spicata), red saltwort, and a thin crust of magnesium sulfate.

  Biology / Life History

Adult crimson saltflat tiger beetles (fulgida subspecies) emerge in the fall (as early as mid-August), begin hunting until colder weather, and then burrow underground for the winter. They re-emerge in early spring (mid-May), begin mating and laying eggs, and then slowly die-off as the summer progresses.

Tiger beetles prey on small insects and other arthropods and are visual hunters. Adults will either chase their prey or wait in a shaded area and ambush prey as it wanders by (Pearson et al. 2006). They often chase their prey in fast, short bursts with brief stops in between runs. These stops are necessary for orientation as tiger beetles can run so fast that they cannot see the prey they are pursuing.

Adults have hind wings that are transparent and they are folded under the elytra (hard front wings) when at rest. When disturbed, tiger beetles may take short, low flights to escape. These escape flights and the ability to run quickly are their main defenses against predators. Tiger beetles are also usually well camouflaged in their environment.

Tiger beetle larvae dig burrows in which they live and secure prey. They are ambush predators that lie in wait in the top of their burrows with their jaws open and their heads and thorax flush with the ground surface, essentially filling the burrow entrance and disguising their presence (Pearson et al. 2006). When prey is within reach, the larvae anchor themselves to the sides of the burrow by two pairs of hooks on their lower backs, and quickly leap out and grab the prey with their mandibles. The struggling prey is then pulled back into the bottom of the burrow and eaten. When they are done eating, the larvae carry the indigestible portions of the prey to the top of their burrow and throw it backwards away from the burrow entrance. The larvae also use their burrow for protection, and will retreat into it when they sense danger. Larvae primarily use vision to detect danger, but may also sense vibrations in the ground created by large predators (Pearson et al. 2006). It is not known how deep the larvae burrow to overwinter.

  Conservation / Management

The crimson saltflat tiger beetle (fulgida subspecies) has very specific habitat requirements (Willis 1967), which formerly occurred in Minnesota only at the Salt Lake location. Its habitat is particularly vulnerable to changes in hydrology, which can cause increased water levels, and conversion of occupied sites for agricultural uses. Run-off from surrounding lands may also be a concern.

  Conservation Efforts in Minnesota

It is not certain if the crimson saltflat tiger beetle (fulgida subspecies) still survives in Minnesota. Surveys for this species should be conducted at Salt Lake when water levels are lower.

  References and Additional Information

Dawson, R. W., and W. Horn. 1928. The tiger beetles of Minnesota. University of Minnesota Agricultural Experiment Station Technical Bulletin 56. 13 pp.

Pearson, D. L., C. B. Knisley, and C. J. Kazilek. 2006. A field guide to the tiger beetles of the United States and Canada: identification, natural history, and distribution of the Cicindelidae. Oxford University Press, New York. 227 pp. + plates.

Willis, H. L. 1967. Bionomics and zoogeography of tiger beetles of saline habitats in the central United States (Coleoptera: Cicindelidae). University of Kansas Science Bulletin 47(5):143-313.