Trapdoor Spider of the Western Transverse Range

15 February 2009

We left early, north on I-15 from San Diego on a trip collecting trapdoor spiders for Jordan Satler's thesis. This was my first trip focusing on spiders and first time to see trapdoor spiders in the wild. They are amazingly fantastic creatures; large, strong, and handsome. It struck me very alien, spending life in the same sunless silken sock-shaped burrow under the ground in solitude; some of these species can live a couple of decades. My advisor Marshal Hedin enjoys sharing images of these beasts. I've included a couple of pictures here and I've linked the species names with images Marshal has posted to Flickr.

Jordan and I, Marshal, and twelve-year-old arachnid enthusiast Jake stopped to pick up Jim Starret, a Ph.D. student at UC Riverside and former undergrad in the Hedin lab. Our focal species was Aliatypus thompsoni, but both Marshal and Jim have research interest in many types of fossorial spiders. Our general route today was to work our way west through the San Gabriel Mountains. We stopped and collected in five localities in Lytle Creek basin, south of Mount Baldy, and in the Big Tujunga drainage. Mountain Chaparral was the dominant habitat. A white-flowered Ceanothus pleased my eyes and California Sagebrush pleased my chemoreceptors. I was definitely the ignoramus of the group and didn't catch a single trapdoor spider all day, but I found some dead-end burrows. I worked on it. I watched the others and I saw intact burrows. With a small twig I lifted a hinged door, noting the amount of silk used in its construction, and setting it back to tightly rest atop the burrow. Fortunately, the others had more success and we secured our sample size from each locality.

Of course I got a little side-tracked by the leaf litter. Flipping rocks and woody debris and sifting oak litter turned up a couple species of millipeds. I was hoping to find the slug Anadenulus cockerelli, known from the San Gabriels, but which hasn't been seen, as far as I know anywhere, in over 60 years. I haven't brought it back, but I haven't given up. I did find some Helminthoglypta which I haven't yet identified. Searching the litter turned up arachnids too. A Globipes harvestmen was fairly common and I collected a couple spiders including a Megahexura under a large piece of woody debris, and a Kukulcania that had built a silken structure in a rolled piece of bark.

Kulkulcania

The trapdoors of trapdoor spiders aren't like the ones that allow stage actors to disappear and drunkards to get kidnapped to sea. Instead of the prey falling through a trapdoor and into the hole, the spider comes to the top of the burrow at night waiting for an unsuspecting meal. When an item passes in front of the door, the spider lunges up and out of the burrow capturing the prey; there's a good couple shots of these doors here and here. And here is a video showing how fast they pop up out of these things.

We drove that night to Ventura and played catch with a football in the Motel 6 parking lot.

16 February 2009

Marshal opened the hotel door wide. The sun had not yet replaced the night and it was pouring rain. Gusts of cold air leapt into the room as the rain pushed down. "Get up!" We hit an eastern locality in the Santa Monica Mountains by 0720 and I quickly collected three Aliatypus thompsoni including the only adult male of the trip. These were my lifer trapdoor spiders, meaning the first time I had ever seen them in the field when I was the collector. They were to be my only Aliatypus of the trip, but at least I didn't get skunked.

We collected up the Santa Clara River near Santa Paula where we likely all got poison oak (nothing has shown yet). We drove a steep muddy road into the Los Padres National Forest. This area is a release site for the imperiled California Condor, but dense fog and steady rain limited how far we could see. We were at least hoping for Mountain Quail, but had to be satisfied with a flock of juncos, a couple White-crowned Sparrows, and Wrentit song. The site was very muddy and I washed my shoes and the bottom of my pants in an ephemeral creek. We continued up the Santa Clara to a site near Val Verde before hoping on Interstate 5 heading north up the Grapevine. We didn't make it far. I-5 was closed due to snow-levels at 3500 ft. It took an hour to get off the freeway. We started playing a game where we would rotate through the alphabet and have to give an arthropod family for whichever letter we got. We went through the alphabet twice and I did fairly well; I pulled out Xystodemidae when I got X. However, I was sorting some millipeds from Idaho last night when I discovered that Keypolydesmidae is fictional; Kepolydesmus is in Nearctodesmidae. I here forfeit any claim to winning that particular name game - winner goes to Marshal. We finally got off the freeway in Castaic; we had to go through a motel parking lot to avoid CHP blockades and follow Ridge Route Rd up into the hills. We found beautiful localities on Templin Hwy and Hard Luck Rd. The snow set off the blue in the Manzanita leaves; the red-tipped chamise helped accent the landscape. Amazingly, I thought, Jim collected a Solifugae digging in the ground under the snow at Hard Luck. I spotted a large Bothriocyrtum door at the Templin Hwy locale and dug out a huge female. She now lives with Adrienne and I; at least she will for a while. I'll keep the tag with her so she can join a collection someday when she passes. No names yet, maybe Rio? From Bothriocyrtum... any ideas? Here's a picture of her.

Bothriocyrtum californicum

Here a list from the trip:

Spiders

Amaurobiidae

--Callobius

Antrodiaetidae

--Aliatypus thompsoni

Ctenizidae

--Bothriocyrtum californicum (California Trapdoor Spider)

--Hebestatis - probably

Cyrtaucheniidae

--Aptostichus

Dictynidae

--Yorima

Filistatidae

--Kukulcania

Hahniidae

--Calymmaria

Leptonetidae

--Archoleptoneta

Mecicobothriidae

--Megahexura

Plectreuridae

--Kibromoa

--Plectreurys

Harvestmen
Nemastomatidae
--Ortholasma

Phalangodidae

--Sitalcina lobata

Protolophidae

--Protolophus
Sclerosomatidae
--Globipes

Boden Canyon, San Diego Co., CA

4 March 2008. 0.9 mi NW of Romana Highlands Road on SR 78. San Diego County, California. N33.0866° W116.9061° to a pond at N33.1168° W116.8936° and back, elevation 270 meters. Ben Lowe and Casey Richart. Coastal scrub habitat, oak-riparian corridor along the Santa Ysabel River; mostly sunny. All images by B. Lowe.


Today Ben Lowe and I went to Boden Canyon to celebrate March Forth. We pulled onto the NE side of SR 78 onto a gated dirt road (Orasco Guejito Truck Trail) and were out of the vehicle at 0900; N33.0866° W116.9061°. Ben soon found 2 small Batrachoceps attenuatus which I collected for Anny Peralta as this location is near a contact zone for two of her population clades. Walking, we followed the truck trail to a small pond at N33.1168° W116.8936° where we ate lunch at 1200. By 1400 we were back at the car. Most of this area had burned in October, 2007.

Many of the birds had started singing: Mourning Dove, Song Sparrow, Wrentit, Oak Titmouse, Orange-crowned Warbler, Hutton's Vireo, Spotted Towhee, Lesser Goldfinch, and Anna's Hummingbird were all heard singing or displaying. Additionally, a pair of Common Ravens flew over with nest material in their mandibles; they flew to the bottom of a steep riparian draw containing Quercus and cf. Platanus (sycamore). A group of about 9 Tree Swallows flew low overhead on the walk in. Most of the coastal scrub has not recovered much of its structure and biomass. However, a NW-facing hillside had much of its shrub layer left, dominated by a white-flowered Ceanothus sp. Here is the only place I saw a suite of coastal scrub denizens including Rufous-crowned Sparrow, Wrentit, and California Towhee. An immature Golden Eagle flew over us at around 1330, initially being chased by a pair of ravens before leaving them for a thermal where another pair of ravens and a Red-tailed Hawk took up the harassment. In the pond was 2 male and a female Ring-necked Duck. In a place where the Quercus canopy mostly covered a boulder-laden stream bank a Canyon Wren called. Other avian life seen on this walk include: about 10 Bushtit, 9 Wild Turkey, Nuttall's Woodpecker, Sharp-shinned Hawk, many Audobon's Warblers, Turkey Vultures, Scrub Jays, Acorn Woodpecker, and House Finch.

Five species of lizards were encountered. Most frequently seen was Scleroperus occidentalis. S. orcutti was seen on a large boulder near where we crossed the Santa Ysabel River. An immature Phrynosoma coronatum was found along the truck trail. Also encountered was an Aspidoscelis tigris and an Uta stansburiana. Ben reported hearing both Pseudacris cadaverina and P. regilla vocalizing along the river. I found another Batrachoceps attenuatus near the pond.


San Diego County has received much rainfall this winter and there were many wildflowers out. As well as many other species, two species of Ceanothus, Gilia angelensis, and a Lupinus sp. were in flower. Dichelostemma pulchellum were also in flower and the were commonly visited by Vanessa cardui as shown in this picture.


A ground-squirrel (cf. Spermophilus beecheyi) was glimpsed near the gate and SR 78. A Ratus norwegensis was mummified in the depths of an old foundation. About 500 meters south of the pond, in a spot where the truck trail is under the Quercus canopy we saw a large, probably male Lynx rufus walking south (opposite our direction). In getting Ben's attention I managed to grab the attention of the bobcat as well; the cat crouched low with eyes and ears trained on us before breaking to a run away from us clearly showing its short tail.