Hacklemesh Weavers, Colony Pheromones, and The Last Bookstore

Tody I Learned:
1) ...a little bit about the hacklemesh weaver, which I suspect may be the species to which my newly acquired lab spider may belong. The hacklemesh weaver is a South American spider that has been recently transplanted to the south-west US and, as far as I can tell, has essentially gone native. They dig burrows, outside of which they build coarse, tube-like-ish webs. The webs aren't sticky, but they're spun out of gajillions of tiny little loops, which trap prey. The weavers have a specialized comb-like structure on their fourth leg, which they use to comb their silk to the right consistency.

Unfortunately, as I'm discovering, in general, spider identification is difficult unless you can get close enough to get a good sense of the eye layout -- the first, most important distinguishing characteristic to look for on any brown spider is the eye layout, which varies quite a bit between species.

2) I already kind of figured that different ant species would use different pheromones. Recently I've been learning about just how different those pheromones are -- not amazingly different, but the variety is great enough that checking what chemicals an ant responds to is a good way of determining the ant's species, and looking at patterns of pheromone chemistry is one of the (many) ways myrmecologists organize evolutionary relatedness among ants. There has even been at least one case where two quite distinct species of ant were misidentified as one species for decades until someone checked what trail pheromones they laid.

Today I learned that pheromones also vary by *colony*, to the point where ants seem can distinguish which colony laid a trail. There's also evidence that *individual ants* have distinguishable trails, so that an ant can specifically follow its own trail and not get confused by other ants'. Mostly the variation comes from differing ratios of standard pheromones.

There must be some kind of randomization that happens early in a colony's development that fixes its pheromone mix, which eventually gets set. I suppose it *could* be genetic, but I would expect too much variation between sisters' trails (most (all?) ants share about 50% genetic similarity to their sisters). A lot of pheromones are apparently produced in the hindgut, which makes me suspect that the ants' microbiomes are involved.

3) Somewhere I need to go -- The Last Bookstore, in downtown LA. From the descriptions I've gotten, it sounds like exactly the kind of magical place I wish I could live in for a couple of decades. Thanks to Chigozie!!!! and friends for pointing this out to me!