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Carnival of Evolution and Giant Jelly Explained

June 7, 2012
by

The latest edition of Carnival of Evolution is now up at Pharyngula. As usual, it’s filled with fabulous posts on evolution (including a fascinating piece on satin bowerbirds and how a researcher used the male birds’ disdain for red things to pick out the smart birds). PZ was also kind enough to include some pictures of his Icelandic adventure in this month’s carnival. Check it out. Now.

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Now onto some old (not that old), but super-cool news: Have you seen the video of the giant jelly?

Wicked cool, but what the hell is it, right?

Thanks to the wonders of the Internet, the esteemed scientists at Monterey Bay Aquarium Research Institute (MBARI) have the answer. The mysterious blob is Deepstaria reticulum and it was discovered in 1966. In the last 20 years, scientists have seen this organism on 29 dives. In other words, it’s old (but still super-cool) news.

Word of the Day: Apophallation

May 29, 2012

There are some things you just need to know, like the fact that Brontosauri never existed.

There are other things you really should know, like the fact that sea cucumbers breathe out of their butts (this little factoid comes in very handy if you have to quickly befriend a 10-year-old boy).

And then there are things you swear you could live without knowing, but let’s be honest—you’ve got questions and right now the most pressing one is probably “what does apophallation mean?”

It’s the deliberate amputation of the penis.

Gasp! I know, the horror, bear with me while I tell you about slug sex (and don’t you dare try to tell me that you’ve never wondered how it works).

Slugs (we’re talking about the big ones like the banana slug at right) are simultaneous hermaphrodites with both a penis and a genital opening on the right side of their heads. When two slugs get it on, they contort themselves into a yin yang-like position as they insert their penises into the other slug’s genital opening. They stay in this “embrace” for hours, both slugs acting as the fertilizer and the fertilizee, and then they separate.

Or try to separate.

Separating can be difficult after hours of entwinement and so they resort to what we might consider drastic measures: They chew off their partner’s penis—and then they eat it…and it’s captured on film, right here. (It’s really not that drastic since slugs retain a completely functional female reproductive system.)

Hence apophallation. (You’re right, you probably could live without knowing that, but wait, there’s more!)

The term apophallation seems to refer to slugs specifically, but they’re not the only animals to deliberately amputate male sexual organs. Orb-web spiders (Nephilengys malabarensis) also dabble in a little Bobbitism—and in their case, it’s a life-saving maneuver.

Male orb-web spiders, much like most males in the animal kingdom, want to produce as many offspring as possible. To do this, the male orb-web spider will have to mate with a female orb-web spider—and that’s not as pleasant as it sounds (for the male). The mating is short and when the female wants to end the copulatory event, she’ll start to eat her mate. BUT, if the male orb-web spider detaches himself from his palp (the spider equivalent of a penis), he can dash out of the female’s reach while his palp remains in his mate’s genital opening. By turning himself into a eunuch, the dude not only saves himself, he also maximizes his paternity.

Say what?

You’d think that once he ditched his palp the mating would be over, but it’s not. The palp continues depositing sperm while the male is running away. In fact, this process (known as remote copulation) results in greater sperm transfer and therefore greater offspring production than the typical orb-web spider method of old-fashioned copulation and sexual cannibalism.

Eunuch-izing himself gives the male some other advantages as well. The abandoned palp plugs the female’s genital opening, thus discouraging other males from mating and minimizing sperm competition. The female can remove the palp, however, making this roadblock technique only about 75% successful. Of course, to attempt to mate with the female, an intact male would have to get to her—and, with a eunuch guarding her web (from a safe distance), this is a difficult task. In lopping off his palps,* that wimpy (but crafty) male transforms into a badass mofo who attacks any male who dares step onto his lady’s web. Kralj-Fiser et al. found that eunuchs were significantly more aggressive, agile** and all-around better fighters than intact males. And so he may be palp-less but he’s alive and those baby spiders will all be his, dammit!

*Males start with two. Full eunuchs were found to be feistier than half-eunuchs.

**They suspect that the increased agility may be due to the eunuch’s, ahem, lighter load as they no longer have to lug those big ol’ palps around.

Li, D., Oh, J., Kralj-Fiser, S., & Kuntner, M. (2012). Remote copulation: male adaptation to female cannibalism Biology Letters DOI: 10.1098/rsbl.2011.1202

Kralj-Fišer, S., Gregorič, M., Zhang, S., Li, D., & Kuntner, M. (2011). Eunuchs are better fighters Animal Behaviour, 81 (5), 933-939 DOI: 10.1016/j.anbehav.2011.02.010

The Dinosaur Post

May 4, 2012

I’ve never really been into dinosaurs. As a kid I knew the basics—Tyrannosaurus Rex, Triceratops and Brontosaurus—but I preferred furry animals. In fact, when asked what I wanted to do when I grew up, I supposedly informed my parents that I wanted to work with furry animals.

While I’d much rather snuggle with a puppy than a fish, I’m not quite as biased towards furry animals anymore. I do, however, have a strong preference for living animals. And so…I’m just not that into dinosaurs.

BUT, I recently learned a few things that have completely shattered my previous perceptions of dinosaurs and, in what will most likely be my only post on dinosaurs, I must share this mind-blowing* news.

First, this guy, whose existence was publicized by Xing Xu, et al. (2012):

from Xu, X et al. 2012

This is the beautiful feathered tyrant, more formally known as Yutyrannus huali.

According to Xu et al., Y. huali was “an extensively feathered gigantic dinosaur.” The feathers weren’t really feathers though. The scientists believe they were more like the fluffy fuzz that covers a baby bird. This—the image of a big bad fluffy dinosaur—amuses me.

The size and fluffiness of Y. huali are especially noteworthy because big things don’t tend to be fluffy. Fur (or fluff) acts as insulation. A small animal (like a pika) has a high surface-to-volume ratio and therefore needs a lot of fur to keep it warm. A large animal (like an elephant) has a low surface-to-volume ratio and can therefore afford to be minimally fuzzy without freezing its bippy.** By that logic a large dinosaur (like Tyrannosaurus Rex) shouldn’t need any fluff to keep it warm. BUT, now that paleontologists have discovered the beautiful feathered tyrant, which was 30-feet long and, of course, fluffy, they wonder… could T. Rex have been at least a little bit fluffy?

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Now for the news that will make children of the ‘80s gasp, cringe or at least say, “huh.”

There’s no such thing as a Brontosaurus—mostly.

In 1879, a paleontologist named Othniel Charles Marsh published his discovery of a new species of dinosaur: the Brontosaurus (aka Thunder Lizard). It turned out that Brontosaurus wasn’t a new species after all. It was merely the adult version of Apatosaurus (aka Deceptive Lizard), a species he had discovered two years earlier. (It also turned out that the skull that topped the Brontosaurus/Apatosaurus skeleton belonged to a completely different dinosaur—Camarasaurus (aka Chambered Lizard).  (More on things they got wrong later.) Unfortunately the folks in charge of naming dinosaurs at the time overlooked the awesomeness of the name “Thunder Lizard” and followed protocol, ditching Brontosaurus in favor of Apatosaurus.

Obviously the name Brontosaurus stuck around for most of the twentieth century. But in 1989, the U.S. Post Office issued a set of dinosaur stamps that included an Apatosaurus labeled “Brontosaurus.” Dinosaur people got pissed and soon the Thunder Lizard was banished from the toy aisle, only to be replaced by its identical twin with the disappointing name.

The Childrens Museum of Indianapolis - Sinclair Dinoland plastic Brontosaurus
This banishment and the wrong-skull incident weren’t the only injustices suffered by the Brontosaurus. In 1905, when the folks at the American Museum of Natural History first mounted the Brontosaurus/Apatosaurus skeleton, they were cocky and judgmental in their knowledge of the creature. They thought the animal was stupid and weak because its small head couldn’t possibly chew enough food to fuel its huge body. There was no way, they believed, this huge weakling could lift its large tail or efficiently walk on land. Therefore, it must have lived in the water.

They were so very very wrong! Scientists have since determined that the Brontosaurus/Apatosaurus actively avoided wet areas; that it could lift its heavy tail and probably swung it for defense; that its small head had no effect on its ability to eat because it chewed its food in a gizzard rather than the mouth; and that it probably stood on its hind legs to reach food and engage in mating battles.

Apatosaurus LeCire
****

One more thing… Pterodactyls weren’t dinosaurs. They were flying reptiles. Dinosaurs, by definition, were reptiles that lived on land. Therefore, pterodactyl ≠ dinosaur. (Frankly, I think this logic is lame.)

*slight sarcasm

**There are some exceptions to this rule, like the large and furry Bison bison (aka bison).

Xu, X., Wang, K., Zhang, K., Ma, Q., Xing, L., Sullivan, C., Hu, D., Cheng, S., & Wang, S. (2012). A gigantic feathered dinosaur from the Lower Cretaceous of China Nature, 484 (7392), 92-95 DOI: 10.1038/nature10906

Baby Birds Bump Off Competition

October 10, 2011

Aww, look at the little birdie feeding the big birdie:

Wikimedia Commons: Per H. Olsen

That’s a mama reed warbler and a baby cuckoo (note that the cuckoo doesn’t fit in the nest). It’s an adorably awkward scene—until you realize how it came about.

 

European Cuckoos are brood parasites, a.k.a. mooches, who pawn all of their chick-rearing duties off on birds of other species. Female cuckoos lay their eggs in other birds’ nests and the other bird (the host parent) incubates the cuckoo egg alongside their own. When the cuckoo chick hatches, it identifies any solid objects in the nest (eggs or hatchlings) and, using the shovel-shaped dent in its back, shoves its foster siblings out of the nest. The host’s eggs fall to their death and the host mother, left with nothing but a big-ass cuckoo in her nest, raises it as her own.

 

And they all live happily ever after (except for the chicks that don’t, of course).

 

Scientists estimate that one-percent of all bird species practices brood parasitism. The strategy enables the mother to devote more time to eating, mating and making more babies (measures of success in ecology) rather than wasting energy building a nest, incubating eggs and feeding and defending her chicks. For the whole plan to work, however, her chicks need to survive and to do that, they’ll need to outcompete their foster siblings. That’s all European cuckoo chicks are doing when they shove the host eggs out of the nest. Sure, they could be nicer about it (cowbird chicks manage to snag more food from their foster parents by simply growing faster than their foster siblings), but they could also be a whole lot nastier.

 

Meet the African greater honeyguide (Indicator indicator). As an adult, the honeyguide is an “indicator”, that guides people to bee hives. As a chick, it’s a little f**ker, that brutally murders its foster siblings.

 

Female African greater honeyguides lay their eggs in the underground nests of little bee-eater birds (who make their nests in abandoned aardvark burrows). The honeyguide mama does her best to ensure that her little bundle of joy will thrive with its host parents. She internally incubates each egg for an extra day to make sure that it will hatch before its foster siblings and, when she dumps her egg off in the little bee-eaters’ nest, she punctures all the little bee-eater eggs she can find. The punctured eggs don’t survive, but some eggs avoid puncturing (or are laid after the delivery of the honeyguide egg) and hatch a couple of days after the honeyguide chick. That’s when things turn ugly.

 

Within an hour of hatching, the little bee-eater chick is attacked by a blind, featherless monster with spear-like hooks on its beak. This monster (the three-gram honeyguide chick) pokes, grabs and shakes its foster sibling for an average of 177 seconds. After a vicious (and apparently exhausting) attack, the little bee-eater chick stops moving and the honeyguide chick stops attacking. The little bee-eater chick dies from internal hemorrhaging and bruising sustained in the attack anywhere from nine minutes to seven hours later.

 

The little bee-eater parents, who were present during the attack but apparently completely clueless about the murder*, continue to feed and nurture the little s**t as their very own. About a month later, the honeyguide emerges from the nest. Its billhook has grown out into a completely normal, innocent-looking bill.

*In their defense, it is completely dark in their underground nest.

 

Warning: The following video is very disturbing:

********

In other siblicidal news, I wrote about sandtiger sharks and other baby animals that kill their blood siblings a few years ago. (Here’s the post.) Just last week, Kevin Zelnio (of Deep Sea News fame) found a video of sandtiger shark siblicide. It is horrifically awesome. Check it out here.

 

Spottiswoode, C., & Koorevaar, J. (2011). A stab in the dark: chick killing by brood parasitic honeyguides Biology Letters DOI: 10.1098/rsbl.2011.0739

Slacker Wrap-Up Part III: Toxic Transport

September 26, 2011

ResearchBlogging.org Remember Nunavut? (It’s Canada’s newest territory.) Most of Nunavut is above the Arctic Circle where it’s pretty dang cold and pretty dang unproductive (in a biological sense). But the two ponds on Tern Island in northern Nunavut are thriving (in a biological sense).

Why? Because of a plethora of poop—bird poop, to be exact.

BUT they’re also toxic.

How can an ecosystem thrive and be toxic at the same time?

The answer is quite simple: Poop.

Let me explain… As they travel to Antarctica and back during the winter, Arctic terns (Sterna paradisaea) eat fish. These fish have eaten smaller fish. The smaller fish have eaten plankton. And the plankton has essentially eaten stuff it found in the water—nutrients and industrial pollutants like mercury and cadmium. So, when the terns eat fish, they’re not only getting loads of nutrients, they’re getting some mercury and cadmium too.

While the terns are flying south and then north again, common eiders (Somateria mollissima) are chilling along the coast of Greenland. Here, the birds chow on mussels and clams. As filter feeders, mussels and clams filter suspended particles out of the water column, filling their bellies (and tissues) with good stuff (like nutrients) and bad stuff (like aluminum, lead and manganese). And when the eiders eat the mollusks, they swallow the chemicals along with the nutrients.

Obviously, birds that eat chemical-laden prey will end up pretty chemical-laden themselves, but to understand the true toxicity of these birds, you have to account for biomagnification.

“Biomagnification: Result of the process of bioaccumulation and biotransfer by which tissue concentrations of chemicals in organisms at one trophic level exceed tissue concentrations in organisms at the next lower trophic level in a food chain.”         -Environmental Protection Agency, 2010

In other words, the birds end up with a whole lot of chemicals in their bodies (even more than the levels present in the prey they eat). And because fish-eating terns are higher on the food chain than mollusk-eating eiders, terns will likely carry a greater toxic load than eiders.

Here’s a visual explanation:

And here’s a visual explanation with a giant baby*:

Now back to Nunavut. Every summer, about 300 pairs of Arctic terns convene at one of the Tern Island ponds and between 50 and 100 common eider hens meet at the other Tern Island pond. What do they do when they return to Nunavut after months of eating?**

(from "Everyone Poops" by Taro Gomi)

And what they eat is what they poop (more or less). Both bird populations offload a s***load of phosphorous into their ecosystems. In fact, total phosphorus concentrations in sediment cores taken from both sites were comparable to those found in sewage oxidation ponds. Of course, phosphorus makes things grow, creating the appearance of a healthy ecosystem. The terns further taint their ecosystem with mercury and cadmium while the eiders further contaminate their ecosystem with aluminum, lead and manganese.

And there you have it: two toxic, thriving ponds on an island in Nunavut.

*Please do not confuse this with the old food pyramid. Babies are not to be eaten, even in small quantities.

** They nest too, but, for the purposes of this post, poop is the priority.

Michelutti N, Blais JM, Mallory ML, Brash J, Thienpont J, Kimpe LE, Douglas MS, & Smol JP (2010). Trophic position influences the efficacy of seabirds as metal biovectors. Proceedings of the National Academy of Sciences of the United States of America, 107 (23), 10543-8 PMID: 20498048

Slacker Wrap-Up Part II: Wind-powered Leaping Larvae

August 23, 2011

ResearchBlogging.org
In a roly-poly world filled with roly-poly things (like tumbleweeds and peas), the ability to transform one’s non-roly-poly self into a blur of roly-poly-ness can be essential to survival.

Huh?

See Exhibit A: The pebble toad (Oreophrynella niger), a tiny toad that lives on the tops of mesas in Venezuela. When threatened by a tarantula, a pebble toad will curl itself into a ball and throw itself off a cliff.

 

Our second example comes from an awesome study [Wind-Powered Wheel Locomotion, Initiated by Leaping Somersaults, in Larvae of the Southeastern Beach Tiger Beetle (Cicindela dorsalis media)] that sets out to answer the question that drives the impish behavior of most 10-year olds: What happens if we poke it?

The larvae of the coastal tiger beetle (Cicindela dorsalis media) live in the sand at Cumberland Island National Seashore. When threatened (usually by the wasp Methocha, but in this study, by humans), the larvae propel themselves off the sand and flip through the air. Such roly-poly behavior is especially impressive because, as the authors point out, “leaping represents serious challenges to soft-bodied, elongate, short-legged or legless animals” like tiger beetle larvae.

Here are the details:

“Without benefit of high-speed video, however, a typical wheeling event looks like a brief and violent bout of thrashing on the sand, interspersed with an occasional leap, after which the larva suddenly and rapidly zips along the surface of the sand in a more or less straight line.”

Translation: To the naked eye, a threatened C. dorsalis media larva is a spaz. But with high-speed video we can see…

“When a larva is touched on the head, thorax, or anterior abdomen, it typically jerks or crawls away, threatens with open jaws without arching backwards, contracts its body into a sinuate death-feigning pose, or regurgitates.”

Translation: When you poke the larvae on the head or chest, it pukes, plays dead, bares its teeth or just walks away.

“When a larva is touched on the posterior part of the abdomen (i.e., from the fifth abdominal segment to the tail), it vigorously arches its body backwards so that its head snaps upwards and backwards and its tail (if not pinned to the substrate) arches upwards and forwards… The momentum of the head end coiling backwards causes the entire animal to roll backwards until the tail of the now-coiled animal contacts the substrate. As soon as its tail contacts the sand, the larva attempts to launch itself off the sand by arching its body suddenly in the opposite direction, using its tail as an anchor. The larva now forms a dorsal-side-out loop that rotates forward while in the air, often completing one to several rotations while airborne. When a larva lands on the sand, it typically will either fall over on its side or else start to roll. In the latter case it will either continue to wheel or else relaunch once its tail (or less commonly head) contacts the sand”

Translation: When you poke the larva’s butt (or anywhere near it), it flips, using its tail as a launch pad. When it lands, it stays in its roly-poly position and either rolls along the sand until it topples over or launches itself into another round of flying somersaults.

“This translates to a typical speed of 0.30–0.56 m/s), assuming a larva travels one body length per rotation. Under the high winds of 2007 (>12.5 m/s), we observed larvae that were wheeling faster than our assistant could run on the beach, which we calculated separately to be around 3 m/s.”

Translation: These guys aren’t all that fast under normal conditions, but in winds of almost 28mph they can wheel at a sub-9-minute mile pace.

Harvey, A., & Zukoff, S. (2011). Wind-Powered Wheel Locomotion, Initiated by Leaping Somersaults, in Larvae of the Southeastern Beach Tiger Beetle (Cicindela dorsalis media) PLoS ONE, 6 (3) DOI: 10.1371/journal.pone.0017746

 

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Slacker Wrap-Up Part I: Eau de Toilette (Literally)

August 16, 2011

ResearchBlogging.orgHi, my name is Kelsey and I’m a slacker. (Note: Pete has progressed past the slacker phase into delinquency.)

I will try to redeem myself—slowly. I have a whole slew (like five) of completely researched and partially written posts. After careful deliberation, I’ve decided that three of them are keepers. I’ve also decided that if I haven’t gotten around to writing full posts on any of these enthralling topics, I never will. Instead, I hope to lure you back to our blog with three post-ettes.

Eau de Toilette (Literally)

Peeing on mates isn’t all that unique (porcupines do it), but it’s certainly noteworthy—especially in an aquatic environment (a.k.a. a giant toilet).

In two no-longer-recent studies, scientists examined the uri-sexual behaviors of two aquatic organisms. In the first species, the sheepshead swordtail (Xiphophorus birchmanni), the male does the noteworthy peeing. In something known as the “audience effect,” these males pee more in the presence of female sheepshead swordtails than when they are alone.

The authors explain the noteworthiness of this behavior here:

“In order to minimize fluid loss, terrestrial animals must concentrate urine and release it in specific times and places. This basic physiological constraint has facilitated the evolution of spatiotemporal control of chemical signaling in terrestrial taxa. Relatively free of this constraint, however, freshwater organisms urinate more or less continuously. Thus, the remarkable degree of control over the release of chemical signals by male swordtails is likely the result of intense selective pressures on males to transfer important information directly to potential mates.”

Translation: Bladder control is essential for terrestrial animals, but freshwater animals essentially live in their toilet, giving them the luxury of being able to pee non-stop, whenever and wherever they want. The male sheepshead swordtail is therefore a remarkable creature simply because it is potty-trained (with the area surrounding female sheepshead swordtails functioning as the potty).

The second noteworthy pee-er is the female signal crayfish (Pacifastacus leniusculus). Male and female signal crayfish play very different roles in child-rearing (males are deadbeats while females provide sole parental care for six months) and approach mating accordingly (males are sluts, females are selective).

When signal crayfish pee, they release aggressive signals that other signal crayfish interpret as something like ‘I’m gonna f**k you up, biotch’. The female crayfish means it, but when a male gets her message he stops peeing because, well, he thinks her challenge is pretty hot. The two fight and while they fight, the female assesses her challenger. If he’s tough enough to thwart her resistance, they mate.

Berry, F., & Breithaupt, T. (2010). To signal or not to signal? Chemical communication by urine-borne signals mirrors sexual conflict in crayfish BMC Biology, 8 (1) DOI: 10.1186/1741-7007-8-25

Rosenthal, G., Fitzsimmons, J., Woods, K., Gerlach, G., & Fisher, H. (2011). Tactical Release of a Sexually-Selected Pheromone in a Swordtail Fish PLoS ONE, 6 (2) DOI: 10.1371/journal.pone.0016994

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