Mystery skull

Ok, not really a mystery, I know what it is, but this is a challenge - and entirely possible with the information contained in the picture (click on it to make it bigger). The only information you get is that it is from Chiloe Island.

I'll post an explanation later. But I expect a couple of you to figure it out first. 

Las mariposas de Chiloe (butterflies of chiloe)

During my stranding in Santiago, I went to a few bookstores and was surprised to discover a guide to Chilean butterflies in one – clearly I needed to buy it. Published in 1996 by two Chilean naturalists, it is a well-illustrated and informative book and all text is in both English and Spanish besides the two forewords one of which is in English and the other in Spanish – and they are entirely different.

Vanessa carye, Chiloe Island

In Santiago, I caught up to Vanessa carye and Phoebis sennae (cloudless sulphur), and on to Chiloe I went.

The overnight bus ride to Chiloe gave me time to scope out the possible species on the island According to the guide, there are 10 species on Chiloe Island – and a detailed survey of the center I am at during 2002 and 2003 turned up 9 of them (Concha-Bloomfield & Parra 2006).

Butleria elwesi, Chiloe Island

The first day here just walking around the center, I found 4 species – including one not found during 2002-2003, again, Vanessa carye, which may be fairly irruptive, like its northern relatives the painted and American ladies - and this year it is common here and in Santiago.  Since then I have found another two species and the other four should be around later in the summer. My goal now is to photograph them all.

Neomaenas poliosoma, Chiloe Island

The radiation of Chilean Satyrnidae, to which this guy belongs, is a group that very little is known of. For what it is worth, I find this species commonly in little forest breaks where fern and bamboo grow. 

Colias vautherii, female

Colias vautherii, male

The above species belongs to the same family as the cabbage white and sulphurs at home. The male is bright orange on the upperwings and the female white/black. 

Eroessa chilensis

This guy is by far my favorite butterfly here. A large, high-flying and gaudy species, this was the only picture I could get of it - resting and nectaring on "michay", Berberis darwini, a holly-like barberry common here and one of many plants that Darwin first collected for western science. 

Sexual selection: Darwin musings

Being at a center named “Senda Darwin”, having just reread the Chiloe section of Voyage of the Beagle, and having tackled his biography – a 700 page tome – this summer, I have been thinking of the great man a bit. What most impressed me of his biography was not the theorizing he did; surely great, but also the part we learn so much about. What impressed me most was his experimentation. When he wanted to learn how plants settled distant islands, instead of immediately embracing completely ridiculous notions of land bridges which many contemporaries and later scientists did (remember that plate tectonics is very young, as theories go), he went about soaking seeds in saltwater for varying lengths of time to see if they would survive, which most did. Of course, as experimentation begets more questions, he found that even while perfectly viable, most of the seeds became waterlogged and sank – which makes drifting to islands pretty difficult.

But what he will be most remembered for, of course, is selection: both “natural” and “sexual”. After saying something along the lines of “the sight of a peacock’s tail makes me sick”, Darwin figured the puzzle out, which he put down as sexual selection in his book The Descent of Man, which I will not profess to have read the entirety of (unlike the Origin of Species and Voyage, Descent is not a short, easy read). Simply, he posited that the choosy sex (usually the female) chooses the opposite sex based on some character and thus that character can become quite ornate. Various hypotheses have been put forth to exactly why, one says that an ornate male – for instance, a peacock male that can survive with such a long tail – is a signal to the female that the male must have good genes.

Peacock, Santiago zoo

And when I was going back through some pictures, I realized I have quite a few pictures of sexual selection – or at least the products of it. 

Fork-tailed Flycatcher, Chascomus, Argentina

Male Fork-tailed Flycatchers display their absurdly long tails in this sort of acrobatic display (accompanied by noise - I'll not call it song) pretty much all day, or at least when any female comes by. 

Saffron Finch pair, Chascomus, Argentina

The Saffron Finches above show a fairly normal sexual dimorphism probably related to sexual selection that basically everyone is aware of: the male is the pretty yellow one on the right and the female is the (also pretty) brown one. Interestingly, in Peru, the same species is also common and both males and female show the bright yellow coloration. Explain that...

But since this is not just about birds, onto other taxa!

Cicada sp., Nantucket

Sexual selection acts not only on coloration and ornamentation, it also acts on behavior. Male cicadas, grasshoppers and katydids (among many, many other animals of many, many taxa) sing for mates, at an increased risk of predation because of this behavior. 

But onto my favorite example of sexual selection, bar none!

Strap-toothed beaked whale, male left, female right

This beast, Mesoplodon layardii, the strap-toothed beaked whale possesses what I believe to be the most ridiculous sexual ornamentation of any animal. Two teeth grow upwards from the lower jaw in males, eventually crossing the top and allowing almost no opening of the mouth, thus adult males limit the size of prey they can eat because of this ornamentation - which is thought to be important in fighting for mates. I talked to a grad student who had dissected at least one of these and she thought the musculature in the throat/lower jaw might be increased and thus allow it to suck food in with negative pressure. 

Let's not forget that we, too, are animals and are thus always trying to impress mates and will dress in ridiculous outfits and do ridiculous things to that end. But a tasteful portrait of costume and ritual:

Gaucho parade, Argentina, Nov. 2010

Cool beetles

As I mentioned earlier, many insects here are bigger and more colorful than those at home. I was walking on a trail near the edge of a forest, when I spied what looked like a big wasp flying by me. Naturally, I netted it and was incredibly surprised to find this in my net.

Long-horned beetle, Nov 14, 2011

Interestingly, it stridulated the whole time it was in the net as well as when I grabbed it. Stridulation is the production of sound by rubbing parts of their body together though I don't exactly know which part it was on this guy (on grasshoppers/crickets it is the wings). The stridulations were high pitched and almost bee-like, which I think may be a form of mimicry, I certainly thought that with the orange body and long legs, it was a wasp and though I did not hear it until later, that may only add to its display. (see here for an older post that discussed bumblebee mimicry in another beetle).

The last picture I took before it zipped away. 

To hear stridulating, the easiest species to find is the red milkweed beetle which occurs on common milkweed basically wherever it occurs. Pick it up and lightly squeeze it and it will cry out! I tell children that it is telling me to let go, and then when they all get a chance to hear it, I say "ok" and let it fly away.

Ceroglossus sp. (magellanicus?)

That picture shows a big, beautiful ground-beetle (Carabidae) that I have found a couple of. I'll detail these guys more, as they are a well-studied genus and quite awesome, but I was excited enough that I figured I'd share it now.

Crazy Harvestmen

Among the many things that are bigger, better and simply crazy here than at home are the harvestman. What on earth is a harvestman? Harvestmen are Opiliones, arachnids but not spiders. Usually referred to as “daddy long-legs” they are common everywhere as scavengers and omnivores. Doug Morse related a story to me of watching one trying to steal the prey from a crab spider! They appear to only have one body segment, unlike spiders which obviously have two, but they actually also have two – they are simply joined together across the width of the body.

Harvestman, 13 Nov 2011

I have found a number of this spectacular species around the center, mostly around rotting logs, though also in our bird boxes. I assume that like the species in New England, these are primarily nocturnal. One of the largest misconceptions – well, let’s say the largest – is the pervasive rumor that harvestmen are incredibly venomous, but cannot pierce skin. This is entirely, completely, and totally false. They do not possess venom glands and having picked up hundreds, I have never been “bitten” (I would guess it is more like stabbing, actually, if it ever happens), so perhaps the second part of that is true. 

This guy makes our species look like wimps!

“Spider bites” in general are grossly over reported and one study I read found that everything from small skin infections to flea bites among others were diagnosed – by real doctors – as spider bites. So enjoy your spiders and harvestmen, don’t be afraid (don't pick up black widows, either...). Scorpions, still another arachnid, stay far away from!

These live in our swallow boxes in Peru. I dropped one on my lap once -
I may never move that rapidly again in my life.