Blind cave spiders make a comeback in Po’ipu

While exploring a cavernous, mud-lined lava tube in Koloa late last year, two Hawai’i scientists came across cave dwellers that have not been seen in 30 years: baby spiders of the endangered and federally protected Kauai cave wolf spider.

U.S. Fish and Wildlife Service biologist Gordon Smith and University of Hawai’i graduate student Wendy Mc-Dowell made the rare find in a survey they conducted in a lava tube.

The discovery of the “spiderlings” with a known population of no more than 30 individual spiders in the world is a “lifetime dream come true” for the biologists, according to Ken Foote, an information and education specialist with the U.S. Fish and Wildlife Service office on O’ahu.

In all, two hatched spiderlings and two still in the egg case were found.

Newly hatched spiderlings are carried on the backs of female spiders for only a few days before they make their own way, Foote said.

“We hope that the sighting of these very unique baby spiders indicate that current management and conservation practices are proving beneficial to the species’ recovery,” Foote said.

“However, only further scientific research like that of Wendy McDowell can provide us with the scientific data to confirm our hopes.”

The eyeless wolf spiders are the most “remarkable cave species in the world,” said Dr. Frank Howarth, an entomologist from the Bishop Museum on O’ahu who is considered the leading expert on the spider, in a news release.

The baby spiders are in the best care for now, their mother’s, he said.

The biologists reported that there may have been more spiderlings in the lava tube they surveyed, but noted they were not accessible to them.

During the survey, the biologists were accompanied by representatives from the private lands that are home to the spider.

The caves in which the spiders call home are found on land that had been owned or is now owned by Grove Farm Company.

Federal government officials set up “critical habitats” on those lands for the protection of the spider and the Kauai cave amphipod, which is also federally protected.

Since 1996, scientists have come across spiders with egg cases, but they had not seen live spiderlings until the ones found in November, Foote said.

Little is known about the spider, but the discovery of the spiderlings could help scientists better understand the origins and evolution of the spider.

The spider was first discovered in lava tubes and rocks found in caves in Koloa in 1971. They caused the alignment of the Koloa bypass road, Ala Kinoiki, to be altered around one such habitat.

U.S. Fish and Wildlife Service staffers have worked closely with private landowners whose properties the spider is found on, said Lorena Wada, a fish and wildlife biologist with the U.S. Fish and Wildlife Service.

And the landowners have been instrumental in protecting critical habitats, permitting the surveys and research on the lands by scientists over the years and by enhancing public knowledge of and support for the species, Wada said.

U.S. Fish and Wildlife Service staffers are working with private landowners to control the entry of humans into areas where the spiders are found, Foote said.

Efforts also are being made to prevent the destruction of native plants above the cave systems to prevent the introduction of nonnative predators and competitors and to control those that are living in areas where the spider habitats are located, Foote said.

Foote said protecting the caves is important, but equally important is the “proper management” of the habitat above the cave, he said. Doing so will encourage the growth of plants whose roots provide food and debris for the cave amphipod, and will increase humidity in the caves that both invertebrates need for their wellbeing, Foote said.

More information on Hawai’i’s endangered and threatened species can be found on www.fws.gov/pacificisland/.

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