just-a-kobold-bard asked: Pssst... The "widowbird" you show there is actually a male Paradise Whydah, family Viduidae. Widowbirds are members of the family Ploceidae. You can tell because widowbirds have red on their shoulders while Paradise Whydahs have red on their chest and yellow on the back of their head. Same concept you talk about applies to these guys, but cool thing about whydahs is that they are obligate brood parasites and mimic the song and nestling mouth patterns of their host!
Clearly I don’t have much of a background in ornithology, haha. Thanks for the heads-up!
Here’s an an actual male widowbird (I’ll edit the post as well):
EDIT: Also, the bit about them being brood parasites is super interesting in the context of sexual selection! In the absence of the females needing to invest much parental care for their young one would think they could afford to be less choosy (then again producing eggs is still much more of an investment than producing sperm).
I KNOW RIGHT?!?
The Viduidae are an AWESOME family of birds… half of them are the indigobirds, which all essentially look alike with only slight variations in plumage and beak/feet color (like, look this species is black iridescent blue and this other species is black iridescent green, oooh different), but each have different songs that mimic the different host species they parasitize. It has been shown that they have probably speciated because of host-switching.
And then the other half of the family are those whack-jobs with the stupid tails, whydahs. I actually have a male Eastern Paradise Whydah as a pet, hence how I immediately went “wait, that’s not a widowbird.” He is super-sexy when he is in plumage.
But why do only a portion of the Viduidae have crazy sexual dimorphism? I’d bet something with habitat and ability to broadcast visual versus acoustic displays or somesuch, but I dunno if anyone has really looked at it.
However, my favorite thing that all the Viduidae do is closely mimic the gape (mouth) patterns of their hosts… it is like some crazy arms race where hosts are trying to identify parasites and parasites are trying to mimic hosts. I mean, look at this shit:
The big one on the right is the Purple Indigobird (parasite) nestling, the rest are the host species, Jameson’s Firefinch. Here’s a closer look at the mouth patterns, which are pretty damn complex:
Definitely some awesome evolution going on there.
Pictures are from here. More information on indigobirds can be found here. Sadly, not as much has been done with the whydahs… maybe that’s what I’ll do for my post-doc. :)
my favorite part of sexual selection is how fucking random it can be. we evo biologists often try to look for fitness correlates, and sure, there is something to be said for a widowbird surviving with that utterly ridiculous tail (i.e., sexual selection is only kept in check by natural selection), and yeah, carotenoid content (which accounts for a lot of red/orange/yellow coloration, which is a relatively common sexually selected trait in birds) can actually be a direct indicator of fitness in some taxa.
but then you have like the female mandrills sitting around like yeah, you’re cute and all, but you know what would be /really/ sexy? if your ass and your nose matched.
and if you could have them match using a weirdly cheerful blue color, that’d be great. come back in like three generations.
Orbital path of asteroid near miss in 2002. Yah, that’s how close we came to nuclear winter and possible total destruction.A visitor.
It’s like it’s trying so hard to hit us and it just can’t do it
IT ONLY FUCKING LEFT BECAUSE THE MOON GRAVITATIONAL SLINGSHOTED IT AWAY
Sorry this has been really bugging me since I first saw it. It seemed pretty unlikely we would have had an asteroid that could cause ‘nuclear winter and total destruction’ inside the orbit of the moon without there being so much as a blip in the news.
So I looked closely at this gif and got the designation number off the orbiting ‘asteroid’. J002E3.
So what was J002E3? Well not an asteroid, and certainly not big enough to be a threat that’s for sure:
Given the spectrum analysis done it’s a part of the Apollo moon rockets. Which is pretty nifty in it’s own right given it’s waltzed out of orbit, back in, been slung off by the moon and is expected to come home for a visit around 2040.
Anonymous asked: What is chase-away selection?
In preparation for answering this question I dipped my toes back into the cesspool of sexual selection theories and MAN is it just a hot sweaty mess. Utterly fascinating, of course, but just a mess.
Ok, so chase-away selection theory. To understand where it comes from, you’ve got to understand a few basic things about sexual selection itself.
We all know what natural selection is, right? Animals that have genetic traits that mean they live long enough to breed get to pass on those traits to their offspring, thereby creating a population with higher and higher percentages of those high-survival traits. Here’s a chart showing what I mean.
Sexual selection is the evolution of the selection of mates. And here’s where it gets really weird. And complicated. Because sometimes what animals find sexy is also what tends to get them killed. Like, check out this male widowbird.
You may not have noticed, but this fellow has a rather long tail. This tail actually gets in the way of flying. Which is important, because birds that have trouble flying tend to be… you know… eaten. That makes it difficult to pass on your genes.
Here’s what the female widowbird looks like, by the way.
You may notice a few differences. Ok, so why does the male of the species look so photoshopped when the female doesn’t? You guys probably already know the answer: it’s because the female gets to be the one that chooses the mates in this species, and they choose males with unrealistic-expectation tails.
The real question is why. Why do the females get to do the choosing, why do they choose tails, why would ANYTHING evolve that lowers an animal’s chances of survival?