When fully grown, larvae burrow to the surface of the galls, where they develop their partially protruding white cocoons and pupate. This species represents one of the rare situations among gall insects where fresh galls and emergence of adults occur throughout the year, depending on location and environmental circumstances, even though there is a pulse of growth and gall activity in spring.

I’ve looked for, but so far have never found, a gall with intact pupae visible on its surface. I’ve found plenty of galls with spent exuviae, however. Here’s one I found a few weeks ago at the salt marsh:

Here’s another gall with visible exuviae. In this case, there are actually several individual galls that I assume were the result of the same egg-laying session, though they have not merged into a single gall, as they often do. I took this shot on the morning after our first good rain of the year; I think the exuviae on the left side of the large gall may have been knocked downward by raindrops:

Here’s a gall with an odd bumpy surface:

For those who don’t want to click through for the full-sized images, here’s a cropped portion of the previous shot so you can get a good look at the exuvia:

I don’t know how long pupation lasts, but I suspect it isn’t very long, or else I should have been able to find some galls with intact pupae protruding from their surfaces. Or maybe I’m misinterpreting Russo’s description of what the pupation stage looks like. Maybe the pupae are near the surface, or barely protruding, and the exuviae end up protruding as much as they do only as a result of the emergence itself.

Here’s a gall with some interesting discolored bumps. I wonder: Could those be pupation sites? If I had cut that gall open, would I have found individual larval chambers under each of those bumps?

Cell biologist Peter J. Bryant at UC Irvine has a neat page on Rhopalomyia californica on his Natural History of Orange County, California web site. Among the photos there are several showing newly emerged male and female midges, the females identifiable by their orange abdomens swollen with masses of eggs.

Although R. californica galls are found mostly in coyote brush, they also can occur in other plants. Dr. Bryant’s page shows a gall in a leaf of black sage and the midge that emerged from it; Bryant used DNA analysis to determine that it was R. californica. He also has photos of four different types of parasitoid wasp that emerged from R. californica galls.

Dr. Bryant was kind enough to correspond with me once before (concerning the bolas spider). I think I might try pestering him again to see if he would be willing to give me any pointers on rearing R. californica galls to adulthood. I don’t necessarily want to harm the insects. Could I simply keep a removed stem in water? Or would it require a living, growing plant to avoid disrupting the lifecycle of the gall’s inhabitants?

Even if I successfully raise gall midges to adulthood, it seems likely that I would be disrupting their chance to successfully breed. The adult midge only lives for a few hours; I would essentially be sacrificing its life merely to satisfy my curiosity. Am I okay with that?

As a young boy I loved Hugh Lofting’s Dr. Doolittle stories. While writing this post I suddenly remembered a passage I hadn’t read in 40 years. It turns out to have been from Doctor Doolittle’s Garden. Doolittle, after long effort, has managed to decipher the language of insects, and has become fascinated by the Ephemera — insects with very short-lived adult stages, such as mayflies (Ephemeroptera) and gall midges (Cecidomyiidae). Doolittle and his young assistant Stubbins (of whom I was always deeply envious) bring a delicate fly into the lab.

We worked on him for half an hour and our results were very meagre. He had things to say, we felt sure. But it was a language new to us. Clearly anyone who has to pack his whole life into one day must talk very fast. We soon got the impression that he was really pouring out hundreds of words a second. Only we weren’t catching them quick enough.

“Look here, Stubbins,” said the Doctor, “we are being entirely heartless. We can’t let this poor fellow spend more than half an hour talking to us. Why, half an hour out of his life is a forty-eighth part of the whole. That would be nearly eighteen months for us. What must he think of us? Imagine anyone talking to you for a year and a half without stopping! Let him go at once. We must do this on a different system. We will catch several singly and only keep them in the apparatus for five minutes at a time, If we are swift enough with our note-taking, we shall perhaps be able to gather a little from what each one says and piece it all together afterwards and make something of it.”

The more I study R. californica the more questions I have. But in answering those questions, I don’t want to harm the object of my curiosity. I’ll have to think about this more.

In early September I received an email from Shoichi Sano, a graduate student working with Prof. Akihiko Matsukuma of Kyushu University Museum. Shoichi had seen Julia’s photo on Flickr, and wanted to know if I might be able to send them a snail specimen. By examining the DNA of R. decollata from different parts of the world, they hope to learn more about how the snails are spreading.

After receiving the email I kept my eyes open at the marsh, but for a while all I could find were old, dried shells. Then in late September there was a light rain one night, and the next morning I found a group of a half-dozen decollate snails crawling near the path that parallels Ash Avenue. Here’s the one I collected:

I’ve always had something of a soft spot for snails; they seem like such peaceful, inoffensive creatures (at least if you’re not their prey, or if your garden isn’t being consumed by them). Deb Talan has a song about snails, “Angels Marching”, on her Sincerely album, and the lyrics have always resonated with me. So I felt bad about killing this snail. But I’d told Shoichi I would, and after researching how to properly preserve and mail it, I dropped the snail into an airtight aluminum pill fob filled with alcohol, wrapped that in enough paper towels to absorb any leaks, and put the whole thing in a padded envelope.

I felt a little anxious waiting in line at the post office. Would my packing job be deemed adequate? I had to fill out a customs form, which required a detailed description of what I was sending. I wrote, “Preserved snail specimen (Rumina decollata)” and handed it in. The postal clerk didn’t even raise an eyebrow. Moments later my “snail mail” was stamped and on its way.

After a few weeks I received an email from Prof. Matsukuma:

Dear Dr. Callender,

I received an animal of Rumina decollata from the Carpinteria Salt Marsh, California preserved in ethanol. Thank you very much for your kind help to obtain the animal from California.

In Japan the invasive land snail R. decollata was found first at Kitakyushu City, Fukuoka Prefecture, northern Kyushu in 1988. At present the snail dispersed in various regions of western Japan, including northern Kyushu, Shikoku, Kinki and Kanto districts. I am afraid the snail will be a serious pest for vegetables in our country near future. I believe studies of origins and migration of the snail are important.

Once again, thank you very much for your kindness.

Best regards,

Aki
Akihiko Matsukuma
Kyushu University Museum

It was flattering, if inaccurate, for him to address me as Dr. Callender; I’m not a PhD, or any kind of scientist (unless you count political science, my major in college, as a “science”, which I don’t). But it was fun to feel included, and to participate, in a small way, in doing some “citizen science.”

It had rained the night before, and was near a max high tide (+5.9), so the basin next to Ash Avenue was full of water, with lots of ducks feeding in the inundated pickleweed. There were mallards (Anas platyrhynchos), blue-winged and green-winged teal (A. discors and A. carolinensis, respectively), and a single female northern shoveler (A. clypeata). In one group of green-winged teal a male was doing a really cute courtship display for the benefit of the nearby females; I’d never seen that before.

A branch of the big arroyo willow (Salix lasiolepis) near the amphitheater had blown down in the wind during the night:

Here’s a shot I took of the Franklin Creek bridge. If you’re used to the bridge’s appearance at an average tide, it’s really noticeable how high the tide is here:

Not far away, a good-sized raccoon (Procyon lotor) had left a trail through the mud:

All in all, a really nice walk at the marsh.

I was surprised to see that there were no Rhopalomyia californica bud galls on any of the plants. I’m not sure why that is. Maybe it’s a legacy of the fire, with the gall midges taking a while to reestablish themselves. Or maybe this is typical of coyote brush stands higher up in the foothills. The Jesusita trailhead is more than three miles inland, while most of my experience with coyote brush has been at the salt marsh and the Carpinteria bluffs, right next to the ocean. Maybe R. californica is more of a coastal species?

At one point I was looking at a spindly clump of burned stems emerging from the center of an otherwise-green coyote brush, when I realized that the exposed stems had the characteristic thickening of the twisted stem gall midge, Rhopalomyia baccharis. I broke off a few of the galls and brought them home for closer examination. Here they are in my hand, to give you a sense of scale:

If you look closely at this shot, you can see the elliptical openings through which the adult midges emerge:

I think these twisted stem galls are fascinating, and I’m always looking for them, but whether it’s that they’re actually rarer, or just that they’re harder to spot in the foliage, I almost never find them. I come across dozens of terminal bud galls for every twisted stem gall I find.

Back in February I found a coyote brush at the Carpinteria salt marsh that had a lot of twisted stem galls; eight or nine at least. I was excited by the find, but I was also in something of a hurry, so I just snapped a few quick photos, intending to come back later and investigate in more detail. Here are some of the shots I got:

The next chance I had to visit the marsh was a few weeks later. I assumed I’d be able to find the plant quickly (the galls gave it a distinctive, gnarled appearance), but I ran out of time without finding it. By the time I could get back to the marsh for a more thorough search it was early April. Even looking more carefully, though, I couldn’t locate the plant. One was in the right spot, but it was much smaller than the plant I remembered, and had no visible galls, so I dismissed it quickly.

Where were the stem galls? I really had seen them; I had photos to prove it. But now they just weren’t there. I wandered back to the center of my search pattern, next to the small coyote brush, and stood there scowling.

And happened to take a closer look at the plant:

Oh.

I suddenly remembered a conversation I’d had recently with Andrea, the head of the docent program, about some new workers hired by the city, with whom she’d had words about their over-zealous pruning of the native plants. The workers had seen the coyote brush with its noticeably gnarled stems, and had done what any self-respecting gardener would do: They’d pruned away the damaged branches.

Sigh. My quest for twisted stem galls continues.

I traded docent shifts with Rob Denholtz this month, so I was there on the third Saturday in July, rather than my usual second Saturday. No one showed up for the tour, though, so I took a stroll through the marsh myself, and was rewarded by a breathtaking profusion of purple flowers.

I’m on record as having a crush on coyote brush (Baccharis pilularis). Linda attended a recent talk by Carol Bornstein, author of Reimagining the California Lawn, and Linda told me coyote brush was among the plants Bornstein discussed.

Bornstein wrote in her book about coyote brush’s “utilitarian” character, and Linda said she called it “fairly drab” during her talk, which of course makes me want to rise to its defense. But I admit that its flowers are not the showiest.

Chaparral mallow is another story. If I have a crush on coyote brush, I felt a temporary transfer of affections to chaparral mallow as I walked past the wall of flowers at the marsh. You really should visit while they’re in bloom.

I noticed some interesting tracks by the boardwalk in the coastal dune habitat. I suspect this collapsed tunnel is from a globose dune beetle (Coelus globosus):

I’m curious what made this trail winding its way down (or up?) this slope:

It reminds me a little of a millipede trail, like this (much larger) trail from 300 million years ago, or this video of a modern millipede leaving its tracks in the sand.

I don’t have any particularly good idea what made this trail. I think I might be seeing a double line, possibly with three sets of footprints outside them:

I previously corresponded with Charley Eiseman (co-author of Tracks & Signs of Insects and Other Invertebrates) about how neat it would be if there was a site like bugguide.net, but focused on tracks and signs. I’m thinking of taking that on; it sounds like it would not be too difficult to set up such a site using Drupal, which I gather is the tool they used to create bugguide.net. I’m not sure I want to take on another project, but it would be awfully neat to have access to a site like that.

We entered on Estero Way, and worked our way out to the mouth of the marsh. Then we retraced our steps, and wrapped around next to the railroad tracks until we could walk out along the dike on the west side of the Santa Monica Creek channel. Toward the southern end of the dike there is a large patch of an invasive non-native with tall spindly stalks; Andrea tentatively ID’d it as black mustard (Brassica nigra). Here’s a shot looking past one of those stalks back toward the northwest:

I took that photo because Andrea had notice something interesting in the plant. Here’s a closer view:

It’s a collection of six spherical objects suspended in a loose web; Andrea’s guess was that they were spider egg sacs. Here’s a close-up:

There was one more interesting thing we noticed: Where the stem holding the spheres met the main stalk of the plant, there was a triangular structure that appeared to be made from the same silk as the web. You can see it on the left side of this picture:

Here’s a close-up:

We couldn’t find any spider to go with the putative egg cases, but after I got home I posted photos on bugguide.net, and within 15 minutes Charley Eiseman, co-author of the upcoming book Tracks & Sign of Insects & Other Invertebrates (which I can’t wait to buy) had ID’d the spheres for me. They are indeed the egg cases of a spider, specifically the Bolas spider Mastophora cornigera.

The spider is nocturnal; it hides in plain site during the day by looking exactly like a rounded bird dropping. (When I mentioned that to Andrea, she replied that she actually had noticed what she thought was a bird dropping on the plant not far from the egg sacs. I didn’t notice it at the time, and I can’t find it in any of my photos, unfortunately.)

The spider also has an interesting way of hunting: It dangles a strand of silk with a sticky ball on the end, and swings it with one of its legs to capture flying insects. The ball gives off a scent that mimics moth pheromones, and researchers have found that the spider can vary the scent over the course of an evening to appeal to different moth species that are active at different times of night.

Here’s a segment from David Attenborough’s Life in the Undergrowth showing M. cornigera hunting:

One mystery I still haven’t solved: What was that triangular silk structure at the base of the stem? I tried sending an email to Peter Bryant, a biologist at UC Irvine who has posted some neat photos of Bolas spiders on the web. I wrote him as follows:

I came across what I believe are some Mastophora cornigera egg cases yesterday at the Carpinteria Salt Marsh. I’m curious about one thing, though: There was an odd triangular structure, apparently built out of spider silk, at the point where the stem from which the egg sacs are suspended meets the main stalk of the plant. You can view a photo of the structure in relation to the egg sacs here:

http://bugguide.net/node/view/356752/bgimage

…and a closeup of the triangular structure here:

http://bugguide.net/node/view/356754/bgimage

At first I was thinking the structure might be a hiding place for the spider, but now that I’ve had some help identifying the species, and have looked at the wonderful photos you’ve posted of the adult female, I don’t think that structure would be large enough to hide one (and it doesn’t sound like they go in for that sort of thing, anyway, given their impressive bird-dropping mimicry).

I’m trying to figure out what purpose that structure might have. My lay speculation so far consists of:

* The aforementioned hiding place for the adult spider.
* A structural reinforcement, to prevent the weight of the egg sacs from causing the stem to break off the plant.
* A barrier to help prevent egg-sac predators from traveling from the stalk to the stem.

I’m curious if you know the answer, or would be willing to speculate. Thanks!

Dr. Bryant wrote me back, but unfortunately he didn’t have any ideas about that triangular silk structure. He suggested visiting the location again to see if the spider is nearby, which I’d love to do, but so far I haven’t had a chance (and I’d need to go with Peter, or someone else with official permission to enter that part of the marsh).

More Bolas spider links:

• Wikipedia article on Bolas spiders
• Bolas spider, Mastrophora cornigera – Interesting photos and captions by Peter J. Bryant.
• Science Spider Friday: The Bolas Spider! – by DailyKos user hekebolos

The chaparral mallows (Malacothamnus fasciculatus) were really in bloom at the salt marsh a month or so ago, when I snapped this photo of a particularly attractive set of flowers. There still are a few mallow flowers here and there at the marsh, but lately it’s the coyote brush (Baccharis pilularis) that has been catching my eye. I think it’s interesting how there are male and female coyote brush plants, with each gender having its own, specific kind of flower. I’ll try to get some photos of those the next time I’m at the bluffs or the marsh.

Linda was the one who taught me to pay attention to the tide. Low tide is her favorite time to check out the rocks at Tar Pits, or walk the beach to the marsh entrance at Sand Point. If the tide is high, she’s not really interested.

But high tide is a great time to visit the marsh. I took a walk there last weekend, and timed it to coincide with maximum high tide. It was a 6.3; that is, the water’s surface was 6.3 feet above Mean Lower Low Water (MLLW). A 6.3 isn’t as high as it gets; at new moon a couple of days later (a couple of days ago, now, as I write this), the tide got up to 7.2.

At 7.2 pretty much all the low marsh habitat, which is dominated by pickleweed (Salicornia virginica), is underwater. Here’s a shot I got last weekend of some pickleweed taking its saltwater bath:

It’s a neat trick for a plant: being able to live in the open air, while also being able to survive immersed in seawater for hours at a time. The high marsh plants, like saltbush, ragweed, mugwort, and sagebrush, can handle a lot, but immerse them in salt water and they’re history.

Because of the tide, the marsh’s plant communities are vertically stratified, and once you learn to look for it it’s really obvious. Going from lowest to highest, the marsh’s major communities are:

• Eelgrass beds – Below the lowest of low tides, in the bottoms of the channels that wind through the marsh, is eelgrass. These are strictly aquatic plants.
• Mud flats – A little higher, in the intertidal zone, are the mud flats. Not much in the way of visible vegetation lives here, but there’s lots of decaying detritus. There are also microorganisms that feed on it, and lots of invertebrates, and aquatic vertebrates (like fish) and terrestrial vertebrates (like shorebirds) that take turns exploiting the flats as the water rises and falls.
• Low marsh – This is the area where the pickleweed reigns supreme. Most of the time this community is above the waterline, but twice a day the high tide soaks its lower reaches, and twice a month (at the time of new and full moon) the high tide goes all the way to the top, killing any would-be invaders from the high marsh, and maintaining the boundary, as level as if it were layed out by a surveyor, between the two communities.
• High marsh – A wider assortment of plants, tolerant of the high salt levels in the marsh soil, but incapable of actually being immersed.

There’s something else that happens during the highest tides in the marsh: Aquatic predators (like fish) invade the inundated area, picking terrestrial insects off the pickleweed stems. I’d love to see that.