Arachnophilia! at Monte Bello OSP

Ant Cricket (Myrmecophilus) near ant nest

Is that guy cute or what? Only 2-3mm long. Read on…

JO, SW, KG and I scouted our hike the night before. Usually we have more time in between, but it had rained on the prior Monday when we had planned to scout. 10/14/11 was a glorious night as far as arthropods go. The weather was in the low 70’s, with some high clouds. I forgot my boots, but as it turned out, it was ok. We saw a few new things, so that made up for it. 10/15 was cooler, and a little windy.

An Osprey soared to the east. We started off at 5:25, and about 10 minutes later on Saturday.

We passed a few ant holes, but as we rounded a curve, we came upon a very busy one. Ants were busily carrying eggs or larvae. As we watched transfixed, I turned and saw a male tarantula crossing the trail ahead of us! For whatever reason we haven’t seen many of these in the past few years. The ants would still be there, so we all gathered around to watch the tarantula walk. Every once in a while he would stop and do a little repeated bounce with his abdomen. I’m not sure what that was about. Some hikers came by and said they also had seen one.

As we returned to the ants, I  saw a tiny reddish brown oval running around near the ants. It didn’t resemble anything I’d seen before, so I managed to catch it in a vial. It was a tiny ant cricket. When I put it back, I blew it off my finger–that caused the ants to speed up. We figured that the CO2 caused them to react as though a predator was near.

On Saturday, we found some small red ants in a nest near the busy larger black ant nest. I don’t remember seeing these before. A lizard was half in a hole, only its back half showing.

The next sighting along the trail was a medium-sized wolf spider. On Saturday, a similar one walked past us in the parking lot.

We’d seen a bowl-and-doily spider, so we stopped to talk about that and discovered a small orb nearby. There was a lack of large orb webs this fall, unlike last year.

We had dinner at the sag pond, arriving there around 6:20 on Friday and about 10 minutes earlier on Saturday. The three spider holes were open, and we were able to see tiny round light-colored babies in one hole. While talking about spider taxonomy, we heard a Virginia Rails call. Sunset was around 6:30.

It took us about 40 minutes on Saturday to reach the first set of woods, where we’d seen the first scorpion (Uroctonus mordax) on Friday. A bat fluttered overhead. We found several scorpions, and refound the trapdoor spider holes (Cyrtaucheniids). Unlike at Long Ridge, the spiders were not at the door. We also checked the hard dirt turret that PB had found previously, which had at least a partial loose silk covering. There was no covering, and the spider perched at the top. A photo revealed that it had finer, denser hairs on its legs compared to Antrodiaetus riversi photos. The turret was taller than the typical A. riversi turrets we see, which are usually not plain dirt.

Scaphinotus beetles were more common than darkling beetles (we only saw one), and on Friday, we found at least four different millipedes and two different centipedes. Several tiger beetle larvae were visible. Either this is a good year for them, or we’ve not had the search image to find them. An Arboreal Salamander was cozy in a trailbank hole, which seems to be where we see them.

Having spent almost an hour along that stretch on Saturday, we decided to skip going to Indian Creek and the gravel pit where we’d only seen a tiny Solifugid on Friday. We continued down the hill, and found one mushroom, being munched on by three crickets. Besides some distant Great-horned Owls, one Barn Owl called.

At about 8:30 we reached the nature trail intersection. We checked the tarantula hole that was stuffed loosely with silk on PB’s hike, and surprisingly, it was open. We didn’t see the spider, but KG found a small Calisoga on the other side of the trail. It was still and cooperative, so we got good looks.

Since we hadn’t yet shown the participants actual turret spiders, we went the .2 miles down the nature trail. Many turret spiders were visible, and JO found a small Hyptiotes with an atypical triangle web between two branches of a fallen log. We also found two fluorescent Polydesmid millipedes, another surprise.

It took an hour to return from the intersection. We stopped to view a Tetragnathid and check the sag pond spider holes.

See photos here.

Update 10/23/11: It appears that, based on my red ant photo, these are army ants! Legionary ants in the genus Neivamyrmex, either N. opacithorax or N. californicus. The busy larger black ants are harvesters, Messor andrei, and they were moving brood probably because of the army ants. See for data on ant species.


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