It’s been a week of intense work (and travel) and unreliable Internet connections, which is why I haven’t been able to post for quite a while. There is so much to catch up on!
I took sample of spiders that I found on acacias in Panama over to the Museum of Invertebrates of the University of Panama (a.k.a. el Museo de Invertebrados de la Universidad de Panamá in Spanish), and they told me that my spider probably belongs to the genus Freya, but not to a known species. That means this might be an entirely new type of spider! But for starters, let me write a little about scientific names…
The current system labels every known species with two names–a genus, which includes a group of closely-related species, and a species name, which indicates a group of animals or plants or fungi (or any other living creature) that is able to successfully reproduce with members of its own kind. For example, lions and tigers both belong to the same genus Panthera, however they are in different species: Panthera leo and Panthera tigris. Since they are related (belonging to the same genus), but not of the same species, it is possible to cross a lion with a tiger (to produce a liger), but that male offspring will probably be sterile (unable to have babies of its own), and females usually have babies that have very delicate health.
Other combinations are also possible, like the jaglion, which is a combination of a jaguar father and a mother lion.
The same is possible with dogs, which all belong to the genus Canis (except for African wild dogs), or bears, which belong to the genus Ursus.
What about humans? At the moment, we are classified in the genus Homo and the species sapiens, although some scientists have argued that we should include chimpanzees (or closest living relatives) and gorillas into the genus Homo as well. At the moment, the genus and species for chimpanzees is either Pan troglodytes for the common chimpanzee (even though it isn’t so common anymore) or Pan paniscus for the dwarf chimpanzee (or bonobo). gorillas are in the genus Gorilla (not surprisingly), and are classified as Gorilla gorilla for the western lowland gorilla or Gorilla beringei for eastern types (like the mountain gorilla of Uganda, Rwanda, and the Democratic Republic of the Congo). While the argument continues, it can be safely (and thankfully) said that crosses between humans and chimpanzees or gorillas and chimpanzees and gorillas probably don’t exist. As far as where I stand on the issue, I certainly see the close similarities between all three species (plus orangutans as well), and they all deserve far more legal protection than they currently receive, but I’m not sure if welcoming all of them into the genus Homo will make a huge difference one way or another. Clearly, though, they are all “people of the forest,” which is very similar to the meaning of the actual Indonesian words orang-utan.
How is any of this related to spiders? Because the only currently known (almost) vegetarian spider is Bagheera kiplingi, which is related to the species Bagheera prosper (of Texas, Oklahoma, and Mexico), Bagheera laselva (of Costa Rica), and Bagheera montagua (of Guatemala). No one has done any study of the diets of other Bagheera (although I am trying to), however it would make sense that if another spider was going to be vegetarian, it should be related to Bagheera kiplingi. So far, I have not seen any evidence of vegetarianism in Bagheera prosper, and I hope to find out if Bagheera laselva is vegetarian in Costa Rica as soon as I have a chance.
What if this other spider–the one I’ve found in Panama–happens to be vegetarian? It would mean that plant-eating in spiders evolved two times, completely independently, because spiders in the genus Freya aren’t closely related to Bagheera at all! They are actually in completely different subfamiliies within the jumping spider family Salticidae.
This would be an amazing discovery, because it might mean that the acacia plants (particularly the species Vachellia collinsii) must have some sort of a special attribute that draws spiders into these herbivorous habits. Of course, it could be that the Freya spiders I’ve found on Vachellia collinsii are there for a completely different reason, but I need to collect more data to be sure!