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“You’ll Do”: Lack of Choosiness in Female Strawberry Poison Dart Frogs
The “blue jeans” color morph of the strawberry poison dart frog, Oophaga pumilio, from Costa Rica.
Image from Wikimedia Commons user Pstevendactylus
Mate choice is one of the most well-studied aspects of evolution. To prove that they’re worth the effort, animals will do just about anything. They dance, prance, sing, bellow, and fight for attention. When you look around the animal kingdom, the wild results of mate choice boldly stand out, from the impractically beautiful tails of peacocks to the ostentatious antlers of elk and deer. With so much focus placed on quality, you might assume that every species has their own complex way of conveying their worth, and that all of the females of the world are finicky creatures.
But not so for the female strawberry poison dart frog — when she’s ready to mate, she doesn’t pick the strongest or the brightest guy around. She just goes for the closest.
This came as a shock to Ivonne Meuche and her colleagues from the University of Veterinary Medicine in Hannover, Germany. Strawberry poison dart frogs are some of the most colorful animals on the planet. There are more than a dozen color morphs, from the bright red they’re named for to vibrant blues and greens. When the mating season arrives, male frogs gather in these large groups called leks to vie for female attention. In other lekking species, these large displays sort the men from the boys in the minds of the females, with the most impressive singers/dancers/etc winning the most matings. It is believed that these large groups give the males a chance to prove their top-notch genes or parenting skills. So the scientists wanted to know what drives mate choice in these colorful frogs. Does their bold coloration play a role? Or, like in other species of frogs and toads, does size matter most?
Listen to a male call:
To test female choice, the team played male calls that varied in pitch and rate made by frogs of different sizes and shapes, and watched to see which the females picked. The female frogs didn’t choose based on any of those factors, though. “We did not find female preferences for certain call properties or physical properties,” the authors explain. “Our data suggest that in our study population, female strawberry poison frogs use a mate sampling tactic that could be defined as “accept the closest calling male”.” When it comes to convincing a female strawberry poison dart frog, a male doesn’t have to be the strongest or the handsomest. He just has to be the first she gets to.
The scientists believe this very non-choosy behavior is a result of the reproductive biology of these colorful little frogs. They found that when a female is ready to lay eggs, she has a short time frame in which to do so. Females that don’t mate in that window end up laying unfertilized eggs, thus squandering their body’s efforts to reproduce. Since time is of the essence, the best choice available for these girls is to take what they can get, for even a lesser quality mate is better than no mate at all.
“Strawberry” is a misnomer: an example of the stunning diversity of color in these little frogs.
Image courtesy of Wikimedia Commons user Dendrotoine85
The authors do note that their study has limitations. Populations of strawberry poison dart frogs vary a lot in the natural world in many ways that the team was unable to test. For example, the proportion of males to females or potential egg-laying sites might shift how females behave. Other studies have found that when there are more females than males, as was true in this study, that the pressure to be picky relaxes. So, further research, in the lab and in the wild, are needed to determine if this species has multiple tactics for choosing mates, or if the closest male always wins out.
But, at least in their study population, the team is confident in their results. And it makes sense — the cost of searching for a better mate is high for these bright little females, so it’s not worth their time to be picky. “High egg mortality as well as the risk of losing the whole clutch by laying unfertilised eggs and the probably low benefits of intensive mate sampling support our assumption that acceptance of the closest calling male represents an optimal mate sampling tactic in female strawberry poison frogs,” they write. The longer these frogs wait to mate, the more likely they are to fail altogether. So why not just pick any guy and hope for the best?
Citation: Meuche I., Brusa O., Linsenmair K.E., Keller A. & Pröhl H. (2013). Only distance matters — non-choosy females in a poison frog population, Frontiers in Zoology, 10 (1) 29. DOI: 10.1186/1742-9994-10-29
GoPro Passes Grizzly Test
Ever imagine what it would be like to stare down the mouth of a grizzly bear? Well, thanks to Brad Joseph and his GoPro, you can find out. Just look at those teeth and claws!
Plus, bonus footage of grizzlies catching fish!
Eau de Manipulation: Malarial Mosquitoes More Attracted To Human Scent
An Anopheles gambiae mosquito gorging herself on blood. Photo by Jim Gathany, from the CDC’s Public Health Image Library
By the time you realize what has happened, it’s too late. An Anopheles gambiae mosquito can land on your skin completely unnoticed. While you continue unaware, she stealthily walks over your exposed flesh, searching, probing the surface of your skin with her proboscis until she finds a blood vessel. She then situates her body perfectly at just the right angle, hunches down, and plunges her needle-like mouthparts into your skin. Tiny pumps pull the warm, protein-rich blood into her mouth.
With every millisecond increasing her chances of exposure, she drinks as quickly as she can. Your hand isn’t the only obstacle she faces: even as she sucks, your body senses the wound and attempts to plug the hole by forming a clot. She needs your warm, nutritious blood for her eggs, so she’s not about to let your protective mechanisms interfere. To ensure her meal keeps flowing, she pumps saliva laden with anti-coagulants and vasodilators into the wound — and that’s when it happens. That’s when the Plasmodium falciprum sporozoites that have been waiting patiently in her salivary glands enter your bloodstream. Dozens can hitch a ride in her saliva, but it only takes one to cause malaria. One single, microscopic protozoan is enough to kill you.
Responsible for the most dangerous kind of malaria and at least half of malaria cases worldwide, Plasmodium falciprum is estimated to kill somewhere between 500,000 and 1 million people every year. In recent years, the parasite has developed resistance to many of our best treatments, leaving doctors without options in the over one hundred countries where malaria is endemic. While scientists continue to research new means of treatment from vaccines to drugs, nations struggling with malaria have shifted focus to prevention. Recently, this means scientists have become particularly interested in mosquito behavior to develop better, cost-effective control mechanisms. But a new study in PLoS ONE today suggests we know less than we might have thought, and that the parasite may be influencing its host mosquitos in ways we never even imagined.
“So far, most studies of Anopheles gambiae mosquito behavior have been conducted with uninfected mosquitoes,” write the authors, “but our data demonstrate that such results may not be representative of infected mosquitoes.” Previous studies found that Plasmodium-infected mosquitos probe skin more, bite more often and ingest larger meals than uninfected ones, but the scientific team comprised of scientists from the Netherlands, United Kingdom, and United States wondered whether infected mosquitos behave differently before they land.
Many parasites with multiple hosts are known to alter one hosts’ behavior to increase transmission to the next. Toxoplasma gondii, for example, suppresses rats’ fear of cats by altering how they respond to feline smells. The research team wondered if Plasmodium could control mosquitos along the same lines, so they tested how uninfected and infected mosquitos reacted to the scent of human skin. Their results were staggeringly significant.
Figure 1 A from Smallegange et al. The total number of landings by uninfected (green bars) and P. falciparum infected (red bars) mosquitos in response to no odor (left) or human skin odor (right).
Infected Anopheles mosquitos landed on the human-scented surface more than three times as often as non-infected mosquitos. “These results suggest that malaria-infectious females are more attracted to human odors than uninfected mosquitoes,” write the authors. “This is the first indication of a change in [mosquito] behavior in response to human odor, caused by infection with P. falciparum.”
The authors hope this research spurs further study into the ways in which Plasmodium alters mosquito senses. New types of attractant smells, for example, could lead to breakthroughs in trapping technology and provide powerful allies in the struggle against malaria.
But the discovery that mosquitos act differently when infected has its downsides, too. If the parasites can change how the mosquitos smell, how much does this alter how they behave? Are the usual battery of deterrent or attractant smells less effective? Is the alluring scent enough to draw mosquitos to feed when they normally wouldn’t, making our nightly netting less meaningful? Are there any other ways that the parasite alters its host, and what do these changes in behavior mean when it comes to bite prevention?
There is a long road ahead before scientists will fully understand the complex interactions between Plasmodium and their hosts. Studies like this one reveal just how little we understand these deadly parasites of ours, and how much more we have to learn if we want to win the battle against them.
Citation: Smallegange R., van Gemert G.J., van de Vegte-Bolmer M., Gezan S., Takken W. et al. (2013). Malaria Infected Mosquitoes Express Enhanced Attraction to Human Odor. , PLoS ONE, 8 (5) e63602. DOI: 10.1371/journal.pone.0063602
Science Seeker Award Winners Announced!
X2!The winners of the inaugural Science Seeker Awards have been announced! My posts got nods as finalists in two categories: Best Biology Post and Best Life-in-Science Post. Thank you so much to the judges for these honors, and a huge congrats to all of the winners and other finalists. I strongly suggest reading through the list of winners and finalists, and checking out all of the fabulous posts!
Musical Monday: Gambler
Welcome to Musical Monday, where I feature an original song just for the heck of it. Want to hear more? Check out my previous musical posts, Time – And Brain Chemistry – Heal All Wounds, Biochemically, All Is Fair, and Taking Einstein’s Advice, and previous Musical Mondays Stay Near Me and As Hard As It Is.
I’ve had a song banging around in my head for awhile, and finally this weekend I took the time to get a very rough draft out. When it comes to love, everything is a gamble. So, enjoy!
Esteemed Journal Nature Dedicates Issue To GMOs, Defends Technology
Anyone who reads this blog regularly knows I have a big bone to pick with the organic movement, particularly with their constant attack on genetic engineering. I applauded when Prop 37 failed in California, and have put out post after post explaining why GMOs aren’t the root of all evil. That’s not to say I’m pro Monsanto, or think every GMO is science’s gift to humanity. But the universal fear and demonization of all genetic technology is, simply put, damaging and unfounded.
Turn that frown upside-down — the newest Nature issue defends GMOs. Cover image provided by Nature.
Now, the top-tier scientific journal Nature has weighed in. In their “GM Crops: Promise & Reality” issue this week, several articles explore “the messy middle ground.” With titles like “Tarnished Promise” and “A Hard Look At GM Crops,” you might think they attack genetic engineering, but in fact, the entire issue does the opposite, standing in support of crop genetic engineering technologies and pleading to rethink the knee-jerk reaction against them. Even the “Hard Look” concludes, “Tidy stories, in favour of or against GM crops, will always miss the bigger picture, which is nuanced, equivocal and undeniably messy. Transgenic crops will not solve all the agricultural challenges facing the developing or developed world… But vilification is not appropriate either. The truth is somewhere in the middle.”
Which is exactly what I’ve been saying all along. Read More
You Are What You Like: What Your Facebook Activity Says About You
Facebook gleefully reported earlier this week that their privacy practices are “A-Ok”, in response to the growing federal concerns that the company leaks too much personal information. While it’s all well and good that they are legally in bounds, users still worry about just how much is shared via the popular social networking site. After all, just what does your Facebook activity say about who you are?
A lot, actually. Read More
Am I Sexy Now? Vocal Cues To Body Size Sound Attractive
What does your voice say about you?
Our voices communicate information far beyond what we say with our words. Like most animals, the sounds we produce have the potential to convey how healthy we are, what mood we’re in, even our general size. Some of these traits are important cues for potential mates, so much so that the sound of your voice can actually affect how good looking you appear to others. Which, really, brings up one darn good question: what makes a voice sound sexy?
Cheater Cheater Mucus Eater: Simple Mechanisms Drive Cleaner Wrasses To Cooperate
Labroides dimidiatus feeding off a plexiglas plate in the lab at the Lizard Island Research Station. Photo courtesy of Simon Gingins
On the surface, cleaner wrasses seem like real nice fish. They set up their little cleaning stations on patches of reef, offering to eat any external parasites that other fish might have picked up. It’s a pretty sweet deal for both sides — the cleaners get a tasty meal, while the other fish get rid of pests. But not all of these do-gooders deserve their squeaky clean reputation. Every once in a while, a cleaner wrasse will take advantage of the situation and take a bite out of the tasty mucus coating of its client instead of eating parasites like it’s supposed to. This cheating behavior has fascinated scientists, who want to uncover what drives the cleaners to cheat, and what keeps them in line.
“They are a very good system to study cooperation between unrelated individuals,” explains Simon Gingins, who is studying the cooperation between cleaners and their clients for his PhD. Cleaner fish are dependent on their clients to eat, as they’re not fast enough to take bites out of fish that don’t sit and wait. “Their cooperative behavior is central to their life: most of what they do everyday is to interact with other fish species to obtain their food.”
My Heart Is Home
I was born in Beth Israel Hospital, and lived just outside of Boston until I was 5. I went to high school in Concord, and when I was a teenager, me and my friends used to spend the weekends in Boston and Cambridge. We used to get sushi in Porter Square, flip through the new CDs at Newbury Comics, and have dinner in the North End. I am a die-hard Patriots fan. My family is scattered around the city in small towns and suburbs. Though I lived many places growing up, whenever someone asks me where I’m from, my answer is Boston.
I was less than 20 miles outside of Boston on September 11th, 2001. One of the kids that held me as I cried then ran today in Boston.
Just a week before, he and I chatted over sushi here in Hawaii. He had come out for a conference, and we talked for hours, catching up on everything that had changed in the decade or so since we saw each other last. We had been on the cross country team together briefly in high school (when I foolishly attempted to become a runner). Unlike me, he’s a natural runner. Always one of the first to finish for our school, his passion for the sport has only grown over time. He gushed to me about the upcoming marathon, with excitement lighting his eyes. Running the Boston Marathon is a point of pride for any runner. Since you have to qualify to get in, even being allowed to run is considered an honor. But today, the finish line normally filled with sweat, relief and joy became a gruesome crime scene.
Thankfully, my friend finished long before the bombs went off.
When I heard about what happened, my gut immediately tightened, and I erupted into tears. I have countless family and friends in the Boston area, and immediately, I started the mental list of who I needed to check in on. The classmate that ran — check. A friend who works in the area — check. One of my closest friends and his partner — check. Classmates, colleagues, family, friends — check, check, check, check. I turned to facebook and twitter, relieved to see so many updates from people who are safe, telling their loved ones that they’re ok. Too many, though, were stories of near misses. People that happened to be working from home instead of the office, runners that finished early or never got the chance to, friends that almost went to cheer them on.
I cannot begin to understand the mind of someone who would do something like this, though certainly scientists have tried.
Some are questioning whether what happened should be labeled a terrorist attack. When a series of bombs explode in streets crowded with innocent people, though, there can be no mistaking the goal. Whoever placed these bombs wanted to hurt us. They timed the attack not to hit the first place racers, but when many more would be crossing the finish line. They blew up crowds of spectators and athletes, regardless of age, sex, race or religion. They stole lives and limbs. They took a day of celebration and forged one of gruesome violence. For whatever reason, whatever cause they sought to further or message they sought to send, they meant to incite terror. They wanted to fill our hearts with fear and rage, to twist our thoughts to hatred and retaliation.
We cannot let them have that. We cannot let them win.
Reactions like Erik Rush’s won’t help anything. We don’t know who chose to commit this terrible act, but we will, and when we do, they will be punished. As Obama promised, “make no mistake, we will get to the bottom of this… We will find out who did this, and we will hold them accountable.” In the meantime, turning on anyone before those facts come in, blaming religious or political groups without any evidence, or making broad threats will only serve to worsen what has happened. If there is one thing that horrific events like this one teach us, it is that hatred is a powerful and destructive force. No good can come of letting ourselves be blinded by it. We will not, as a nation, be coerced to become as twisted as those who placed the bombs today. We cannot.
What I have seen more than anything over the past few hours are outpourings of love and support. People around the world are expressing their honest concern and hope for the people of Boston and the families and friends of everyone involved. That is what we need.
There will always be bullies. There will always be extremists whose thoughts are so distorted by hate that they lose their very humanity, making them capable of unspeakable crimes. There will always be tragedies, and though we hope to prevent as many as we can, we will never be able to prevent them all. But there will also always be reasons to hope and love. There will always be everyday heroes, from the first responders who bandaged at the blast site to the nurses and doctors still tirelessly striving to save lives. There will always be those who risk their own safety to help those in need. There will always be selfless, kind, caring people, and those people far outweigh the few monsters who commit acts like this.
My heart is with you, Boston. Though my body is 6,000 miles away, my heart is home.
Links:
- Can’t find someone? Google has set up a people finder to track down missing loved ones
- Anyone trapped by the race or living in the area with a couch to spare, go to the Boston Globe-run form to let others know
- Mayor’s hotline for people looking for friends/family: 617-635-4500
- Anyone with videos/pictures of the route call 800-494-TIPS or the FBI at 1-800-CALL-FBI (prompt #3)
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