March 27, 2016
The BBC is working on a documentary film about the Yucatan and for some time one of their researchers, Alec, has been writing to me for background information. The other day Alec mentioned that he'd like to incorporate footage of a "vegetarian spider," Bagheera kiplingi, a Neotropical jumping spider occurring from the Yucatan south to Costa Rica. I'd never heard of the spider, but learned all about it in a paper by Christopher Meehan and others, entitled "Herbivory in a spider through exploitation of an ant-plant mutualism," in a 2009 issue of Current Biology. The paper can be downloaded from http://www.sciencedirect.com/science/article/pii/S0960982209016261
In our area the spider occurs on the Bull-horn Acacia, nicely illustrated on our page at http://www.backyardnature.net/yucatan/acacia-t.htm
On that page we see the tree's superfluity of swollen-based thorns, and holes in the thorns through which the ants pass who reside inside the thorns. When the tree is disturbed, as by a herbivore grazing on its leaves, the ants rush out and deliver stinging bites, thus defending the tree. The tree reciprocates not only by providing lodging in its thorns but also by producing tiny, yellow "Beltian bodies" at the tips of young leaflets, Beltian bodies being rich in protein, and providing food for the ants. All this has been known for a long time. What's new is the "vegetarian spider" who also feeds on Beltian bodies instead of killing prey. Meehan and his group describe their paper as ".. the first report of a spider that feeds primarily and deliberately on plants."
Upon reading the above article I went to see who might be roaming the leaves of Bull-horn Acacias near the hut. Normally our Bull-horns are leafless at this time of year, but during the last month we've enjoyed three puddle-making rains, so things have greened up surprisingly. I mention this because I've seen Beltian bodies only on newly emerging leaves after good rains. Maybe after our recent rains the Bull-horns would bear some new leaves with Beltian bodies.
The first Bull-horn Acacia I checked bore no new leaves or Beltian bodies, and only a few ants wandered among thorns and few remaining older leaves. The second tree, however, in a shadier environment and with the ground around it covered with moisture-conserving leaf litter, was indeed producing a few new leaves, and the leaflets bore tiny, egg-shaped, orangish-yellow Beltian bodies. Moreover, hundreds of ants swarmed all over the tree, and some were harvesting Beltian bodies, as you can see at http://www.backyardnature.net/n/16/160327bb.jpg
Meehan's paper says that in the Yucatan the ant species his group had seen harvesting Beltian bodies was Pseudomyrmex peperi, and I assume that that's what we're seeing in the picture. To help with identification, a side view of an ant scurrying away carrying a Beltian body is at http://www.backyardnature.net/n/16/160327bc.jpg
I had hardly hoped to find the "vegetarian spider," Bagheera kiplingi, but lo and behold a jumping spider turned up on a leaf right before my face, shown at http://www.backyardnature.net/n/16/160327bd.jpg
Was this the vegetarian? Later I'd see that it was similarly structured but differently colored than those in pictures of the species on the Internet, though it almost matched some pictures. The species is known to be variable so I'm thinking that this is indeed the "vegetarian spider," Bagheera kiplingi, though I can't be for sure.
Meehan's paper says that the diet of spiders studied in the Yucatan consisted of about 91% Beltian bodies, though in Costa Rica only about 60%. They supplemented Beltian bodies with nectar from glands at the base of acacia leaves (shown on our Bull-horn Acacia page), plus they occasionally abandoned their vegetarianism and preyed on larvae of the acacia ants, as well as small, nectar-feeding flies, and (rarely) other "vegetarian spiders" smaller than themselves. On a second visit to the tree I didn't see the spider in our photo, but there was another jumping spider, much smaller and pale yellow, which I thought might be an immature "vegetarian spider."
It's hard for me to envision the spiders preying on the ants' larvae because the spider I watched spent a lot of time avoiding the ants. I didn't see the spider feed on Beltian bodies, or even get close to the smaller, ant-infested leaves bearing the bodies.
One final note about this amazing spiny-acacia/ Beltian-body/ ant/ spider relationship is that, at least in our area, yet another species seems to be involved. Every Bull-horn Acacia I've seen lately bears at least one melon-sized paper-wasp nest, the wasps obviously choosing the acacia's spiny branches over non-spiny ones.
I guess that the benefit to the wasp is that small animals are less likely to climb a spiny tree to feed on the wasps' larvae. However, what about the larva-eating disposition of the "vegetarian spider," and possibly of the acacia ants themselves? We've documented marauding army ants robbing a paper-wasp nest of its larvae, at http://www.backyardnature.net/yucatan/ant-wasp.htm
Meehan and his group have described a very interesting web of relationships centering around the Bull-horn Acacia, but maybe the web is even more intricate and surprising than his paper documents.
SLENDER DWARF MORNING-GLORY
During the last month we've enjoyed three puddle-forming rains, which is unusual for the mid dry-season in this part of the world. The rains have suspended the usual uninterrupted march toward April and May's mind-numbing, strength-sapping dry heat, glare, and air acrid with smoke. Suddenly there's a little flush of greenness, of returning mosquitoes, and a softer feeling in the air.
So, when I went looking for herbs that might be emerging after these rains -- most herbs here die back during the dry season -- I found something in thin soil atop limestone bedrock outcropping on the floor of a shaded forest trail. You can see the small plant with its single pale blue flower only about 5mm across (1/5th inch) seemingly very out of place in such usually-baked soil in the dry season, at http://www.backyardnature.net/n/16/160327ev.jpg
At first glance the tiny flower shows no special features to help with identification, as you can see closer up at http://www.backyardnature.net/n/16/160327ew.jpg
As with the blossoms of many other species, the corolla is divided into five lobes and there are five stamens alternating with the lobes. However, something might be going on with the styles. The "standard blossom" botany students keep in their head has an ovary with one style tipped with a stigma, but here two or three very slender, crooked styles are emerging from amid the stamens. A side-view was taken, trying to figure things out, shown at http://www.backyardnature.net/n/16/160327ex.jpg
One style seems to be branching midway its length, so maybe we're seeing two styles, each of which branches halfway up. That's possible, because we've seen it in other flowers. Also, have you been noticing how this the surfaces of this flower's corolla lobes appear are creased or pleated? Flowers in the Morning-Glory Family tend to be folded during their bud stage so that when the corolla expands it's pleated where folding had taken place. And certain morning-glory flowers bear two styles branching halfway up...
Last June in Río Lagartos on the Yucatan's northern coast, also in very thin soil atop outcropping limestone and also right after some rains, we found the Dwarf Bindweed, Evolvulus convolvuloides, which was very similar to our present plant, as you can confirm on our Dwarf Bindweed Page at http://www.backyardnature.net/mexnat/bindweed.htm
The genus Evolvulus is home to several species that don't twine as the vast majority of members of the Morning-Glory Family do, so here we have another Evolvulus species, one that's hairier, has different-shaped anthers, and normally produces only one flower per stem node instead of the two or more of the Dwarf Bindweed.
Our present species often is called the Slender Dwarf Morning-glory. It's EVOLVULUS ALSINOIDES, native to tropical America, occurring throughout Mexico, and is invasive throughout most of the rest of the Earth's humid tropics. Though often plants occurring on thin limestone turn out to be rare species specially adapted to quickly drying-out soil with high calcium content, the Slender Dwarf Morning-glory is considered a weed specializing in disturbed sites such as roadsides, pastures and agricultural fields. It's known to flower all during the year.
Despite its weed status, it's such a small plant -- only reaching about 50cm (20 inches) that farmers don't consider it as too troublesome. Whether it's a weedy wildflower or a flowery weed, this week it was good to make its acquaintance on that shadowy little trail through the woods.
GARCIA FRUITS MATURING
Back in 2012 I identified a small tree in the forest near the hut here at Hacienda Chichen as Garcia nutans, a little-known tree of the Euphorbia or Poinsettia Family inhabiting moist forests from Mexico's southern lowlands and the Caribbean islands south to Columbia. Its page, showing immature fruits as they looked in January of that year, is at http://www.backyardnature.net/yucatan/garcia.htm
This week I found another Garcia not far from the first one, and this one's fruits were more matured, and looking like no fruits I've ever seen. You can see them with their outer husks about to be shed, at http://www.backyardnature.net/n/16/160327gb.jpg
A closer look is at http://www.backyardnature.net/n/16/160327ga.jpg
Now there's a little more information about the species available and I see that the species is listed on "The IUCN Red List of Threatened Species" as Endangered. The IUCN page with this information is at http://www.iucnredlist.org/details/38410/0
That page describes it as occurring only in Columbia, but both the University of Mexico's CONABIO and the Yucatan's CICY list it for our area, and a Smithsonian page puts it in Panama.
This is a taste of how relatively poorly many species are known in the tropics, and, apparently, how understaffed and underfunded certain important, non-profit agencies are. I have shared with the IUCN my information from the CONABI and CICY websites.
TOBACCO & PAPAYAS
At the edge of Hacienda Chichen's organic garden a very familiar plant turned up, shown at http://www.backyardnature.net/n/16/160327ni.jpg
It was a Tobacco plant, NICOTIANA TABACUM, and it was familiar because I grew up on a tobacco farm in western Kentucky. As a kid I spent plenty of time setting, watering, hoeing, suckering, topping, cutting, and hanging tobacco in a barn. Back then I was thankful to go to school during fall's crisp days when the tobacco's "cured" leaves were tied into "hands" by my father and grandfather, and stacked along the barn's walls, later to be carried to market, to auctioned. You can imagine the memories and associations that seeing that Tobacco plant brought to mind when I first saw it here, and how strange it felt seeing it next to the Hacienda's Papayas. However, Tobacco is native to the Americas and often I've seen it growing wild in Mexico.
This lone Tobacco plant next to our Papaya plantation was doing something I'd seldom seen the species do: It was bearing a full head of flowers, shown at http://www.backyardnature.net/n/16/160327nj.jpg
A close-up of a flower is at http://www.backyardnature.net/n/16/160327nk.jpg
Back on the farm we never let our plants develop such flowering heads because as soon as the first flowers appeared we walked down every row in the field plucking the heads off. This upset the many Ruby-throated Hummingbirds and butterflies who craved the flowers' nectar, but we knew that if the flowers were allowed to grow, much of the plants' resources would be squandered on them and the subsequent fruits, not on the leaves that meant money to us. You can see one of our garden plant's leaves at http://www.backyardnature.net/n/16/160327nm.jpg
Compared to leaves on our Kentucky plants, this Yucatan plant's blades were small, and I knew why. Not only had no one clipped off the flower clusters -- "topping" we called it -- but no one had "suckered" the plant, either. Suckering was when you snapped off secondary branches forming along every plant's stem. The idea was to have a plant with one stalk and no flowers or suckers, just leaves.
As a kid in the fields I'd felt bad about clipping off the flowers, depriving the hummingbirds and butterflies of their meals, but I'd felt even worse about the sticky gum that accumulated on our clothes and bodies as we worked among the plants all day. The gum was so sticky that body hairs plastered themselves to the body, and dirt and leaf tatters did, too. Tobacco's vegetative parts are thickly covered with hairs tipped with sticky glands, as shown at http://www.backyardnature.net/n/16/160327nl.jpg
Around here from time to time you see one or two Tobacco plants in people's yards. Mostly it's grown as a novelty, or because it's a handsome plant, but my Maya friends also tell me that certain people smoke and/or chew their leaves, though I can't visualize the curing process properly taking place in this climate, or how you'd smoke or chew uncured tobacco. Curing consists of having the hung-up plant pass through several cycles of drying out and becoming moist, in the process turning from a green plant to one displaying the rich, brown "tobacco color."
Without my family's income from growing tobacco, I'm not sure I'd ever been able to go to college. However, without tobacco, maybe some close members of my family -- smokers, all -- still would be alive. It's a beautiful plant, but I despise the notion of smoking or chewing it.
Our Tobacco plant, Nicotiana tabacum, is just one of numerous Nicotiana species. In Mexico's uplands we've seen Tree Tobacco growing wild. You might enjoy seeing what that looked like at http://www.backyardnature.net/mexnat/tree-tob.htm
A while back a visitor at the Hacienda reached into her pocket, pulled out a little box, and removed from it some flower seeds a lady at another hotel had given her. I planted them, they soon germinated, and for maybe two months I've been watching the plants -- more than once shooing big, hungry Black Iguanas from them -- and this week the first bud opened into the pretty little Cosmos flower shown at http://www.backyardnature.net/n/16/160327co.jpg
For me the blossom evokes lots of associations: The lady who gave the seeds to me, the iguana chases, my many visits to the plants wondering which flower bud would open first, time spent watching the plants' ferny leaves quietly soak up mid afternoons' scorching sunlight while I imagined the rush of photosynthesis taking place inside each leaf, visualized the leaves snatching untold billions of carbon dioxide molecules from the air -- many from my very breath -- the captured carbon dioxide molecules inside the leaves' intensely green-glowing mesophyll splitting and reconfiguring with other atoms to form carbohydrate, while currents of pure, life-enabling oxygen streamed through the leaves' stomata into the shimmering air around us.
Of course, the Cosmoses weren't doing anything that all other green plants also were doing. However, the Cosmoses had my attention in a special way. You could say that I had become enchanted with them... maybe in a childlike way, or maybe just in the way you become enchanted with any being, once you really start paying attention to them. Those plants had become friends.
In fact, one afternoon when it was beginning to cool down I sat with my chair next to the first flower and I thought: What if a cute little tourist-girl came by and wanted to pluck this flower for her hair? I wouldn't let her take it. It would be like plucking the head off someone close to me.
It was a funny thought, but it got me thinking further in the same vein.
And that further thought was nudged along by recalling that the Six Miracles of Nature concept outlined at http://www.backyardnature.net/j/6/ teaches that the Universe evolves toward ever higher states of understanding and feeling. In that light, my empathy with the Cosmoses was harmonious with the general flow of the Universe, and that, I thought, was Good.
But -- then I thought -- if everyone developed intense empathy for all living things, eventually wouldn't the most exquisitely evolved/refined among us grow unable to kill fellow creatures to eat them, or even to pay others to kill for them? Might not then everyone not only become vegetarians, but also cease to eat harvested grain, algae or any vegetative tissue at all, simply being unable to continence the thought of chewing and swallowing organisms that had been killed for them? Could it be that the Universe is programmed so that beings with the most matured mentality develop such overwhelming states of empathy with other living things that at some point they stop eating the foods their ancestors evolved to eat, and voluntarily disappear in what could be called a nirvana of profound love for all living things, and self-denial?
At this thought I shook my head, stood up and began preparing for the four o'clock walk through the Hacienda grounds. Really, what good does it do to see advancing shadows of self-annihilation in a bowl of crunchy granola topped with banana slices and yogurt?
Again I shook my head, gave a last glance at the first Cosmos blossom of the season, and wandered off to meet my tourists, and maybe later end the day with a nice bowl of crunchy granola.
Best wishes to all Newsletter readers,
All previous Newsletters are archived at http://www.backyardnature.net/n/.