As I had feared, my Internet connection wasn’t very reliable during my time in Mexico, so I haven’t really been able to post much until now. That’s not to say I couldn’t access the Internet completely, but the connections went in and out, which made it difficult to write anything that would take more than a few minutes (like a blog).
Like most places that I’ve been, it was the rainy season in the Caribbean part of Mexico, so I knew that my work would be interrupted periodically by the rain. Considering that the spiders I’m looking for are smaller than a raindrop, it would make sense that they would try to hide whenever the rain started falling.
So rain it did–rain has been following me everywhere! There were drenching downfalls several times, including two while I was out “in the field.” I put that last part in quotes because I wasn’t really in a field at all–it was an access road cut across the limestone bedrock in order to let workers reach the power lines that stretch all the way down the “Riviera Maya.”
The access road cuts through a stretch of tropical dry forest and private lands that aren’t really developed; it appears to me that the land was probably cleared a long time ago (maybe in the days of the Maya civilization) and hasn’t really been used much since. The region isn’t really great for agriculture, since there isn’t much in the way of soil–just a thin layer of organic material covering limestone rock.
The good news is that Vachellia collinsii, my treasured ant-plant, grows very well in poor soil, because it is leguminous and has bacteria that can fix nitrogen in its roots. For those who might not know, nitrogen is a gas that makes up almost 79% of the air around us, but most of it is in a form that most living things cannot use. It is essential for life, however, since it is required to make proteins and nucleic acids (DNA and RNA). The only organisms that are able to take nitrogen in its atmospheric form and convert it into a useable form are certain orders of bacteria, some of which have taken up residence in the roots of certain plants. Most plant fertilizers contain a form of usable nitrogen, so these plants (including Vachellia collinsii) have found a way to make their own fertilizer by allowing these nitrogen-fixing bacteria in their roots. That allows them to live in poor soils where many other plants might not grow.
The greatest news of all is that I was able to find plenty of vegetarian spiders; in fact Bagheera kiplingi in this part of Mexico is the most vegetarian of all (90%, as opposed to 60% in Costa Rica). Why they are so herbivorous here opens lots of room for research, which I hope to report on soon!