Monday, August 14, 2017

Will the Ocean Ever Run Out of Fish?

Will the ocean ever run out of fish? To us the oceans are vast. But, in reality, they are a finite resource. Here are two videos for you to consider:

Will the Ocean Ever Run Out of Fish?:


Ending overfishing:


(note: because this was made in 2012, some of the stats are out-of-date, but the concepts still hold true)

Wednesday, August 9, 2017

Which Piece of Lab Equipment Are You?


This is a fun little quiz from SciNote. How do your habits in- and outside of the lab reflect your personality, and what piece of lab equipment does that translate into?

Find out: WHICH PIECE OF LAB EQUIPMENT ARE YOU?



I got a scanning electron microscope!



Monday, August 7, 2017

Smells Like Development

A parody of Nirvana's "Smells Like Teen Spirit" all about development and model organisms.

Plants!


Thursday, August 3, 2017

The Great American Total Eclipse 2017: What You Need to Know


A total solar eclipse is one of nature's great wonders, and something we should all try to see. On August 21, 2017 there will be a total solar eclipse that can be seen across North America. All 50 U.S. states will be able to see a full or partial eclipse!  Why is this such a big deal? Well, besides the whole 50-state thing, the last total solar eclipse in this part of the world happened in 1979, and the next one won't be until 2024. There's a lot of information out there. The overriding theme will be Plan! Plan! Plan! Now, what do you need to know and what can you click to find the best information?

1.) How much will you see?


That depends on where in the U.S. you live. Even if you are not in the "path of totality," everyone will be able to see at least a partial eclipse. Up in Maine you'll see 50 percent and down in southern California you'll get 70 percent. And Canada...you'll get some too. There are interactive maps online like NASA's Total Solar Eclipse Interactive Map and Google's Solar Eclipse Map to help you figure out the details. And if you are in to GIS, you can even download maps and shapefiles through NASA's Scientific Visualization Studio.
Image Credit: NASA’s Scientific Visualization Studio

2.) How long will it last?


Not long. Totality (a.k.a., complete coverage of the Sun) will only be 2 minutes and 40 seconds, depending on where you are. Of course, you do have the additional time when the dark shadow of the moon (the umbra) is moving across the Sun, before and after totality. Consult NASA's Total Solar Eclipse Interactive Map to find out exactly what your times will be.

3.) Where should you go to see it?


The hard-core eclipse chasers (an many other people) made hotel and campground reservations months ago. But that doesn't mean that you can't still walk out your door or drive a short distance to see something really great. Of course, weather is a big issue, can't see the eclipse if it is covered by a blanket of clouds. Where I live in North Carolina, the forecast is iffy on any particular day. But other parts of the country, particularly the western portions, have much better odds of good weather. Check Eclipsophile for "climate and weather for celestial events."

In general, plan for mobility and be flexible. Plan a couple of nearby places and be willing to hop in the car if conditions turn unfavorable beforehand. Also plan for traffic. This is a big event and millions (yes, millions!) of people will be out for it. You don't want to miss totality because you were stuck in your car on the highway. Check this Eclipse Web App for real time traffic data.

Still not sure where to go? Look for events near you. Museums, libraries, zoos, and so many more are planning events. That's my plan. Check NASA's Event Locations and the American Astronomical Society's (AAS) Events and Activities pages to find a place to go.

Don't want to leave your house? That's OK too! NASA Television is offering a special live program, “Eclipse Across America: Through the Eyes of NASA” with real-time coverage of the event from coast to coast. The nearly four-hour program will include images from numerous spacecraft, high-altitude aircraft and balloons, and ground observations. Additionally, the broadcast will include live coverage of activities in parks, libraries, stadiums, festivals and museums across the nation, and on social media. To watch the NASA TV eclipse broadcast online and access interactive web content and views of the eclipse from these assets, visit: NASA EclipseLive



4.) How do you keep from burning out your eyeballs?


Yes, this is a very real threat. You need to protect your eyes. Staring straight at the Sun, even if it is in partial eclipse, is not a wise decision if you want to keep your vision intact. And, no, dark sunglasses are not good enough. Luckily, there are few things you can do:
  • Eclipse Glasses - These are simple, cheap, special-purpose solar filters that you can wear. According to NASA, you need glasses that meet the ISO 12312-2 safety standard. These allow you to look at the un-eclipsed or partially eclipsed sun through them for as long as you wish. Make sure the filters in the glasses aren't scratched, punctured, or torn. Make sure to read the instructions on your glasses because some are printed with warnings stating that you shouldn't look through them for more than 3 minutes at a time and that you should discard them if they are more than 3 years old. Look through the AAS Reputable Vendors of Solar Filters and Viewers page before purchasing your glasses and some tips on what to look for and what to avoid.
via NASA's Eclipse 10
  • Pinhole Projection - This does not mean looking at the sun through a pinhole. It is an indirect way to view the eclipse that utilizes shadows. These methods have poor resolution and you won't be looking directly at the Sun, but these are by far the cheapest and easiest way to see it.
    • The Waffle Finger Method - Cross the outstretched, slightly open fingers of one hand over the outstretched, slightly open fingers of the other, creating a waffle pattern. With your back to the Sun, look at your hands’ shadow on the ground. The little spaces between your fingers will project a grid of small images on the ground, showing the sun as a crescent during the partial phases of the eclipse.
    • The Reflection Method - Use a small mirror to project an image of the Sun onto an adjacent shaded wall or more effectively projected through an open window into a darkened room. Be careful not to reflect light in to any eyes that may be in the room.
    •  Making a Pinhole Camera - This only requires some paper, aluminum foil, scissors, tape, and a paper clip! There are some great videos online as well as instructions on how to make your own pinhole camera.


5.) Can you take pictures?


Sure. But know that when pointed directly at the Sun, you can damage a variety of lenses. For binoculars, cameras, and telescopes, there are special filters that you can buy if you want to photograph the event (don't make your own). The AAS guide on shooting eclipse images and videos is great for the more advanced photographer. But a majority of us will probably want to use our phones. The best way to protect your lens is actually pretty simple: Use your eclipse glasses. Just don't look at the Sun when they are off your face and on your camera. Here are some great tips about how to do smartphone photography of the eclipse.

Some advise though...don't spend so much time taking pictures that you miss the enjoyment of seeing the eclipse yourself.

6.) How can you be a contribute and be citizen scientist?


So many ways! Find out how to collect data and be a citizen scientist at NASA's Citizen Explorers page. Google is putting together a unique project called the "Eclipse Megamove 2017" that will document the view of the eclipse across the entire path. To do this, they will gather images from other 1,000 volunteer photographers, amateur astronomers, and the general public across the eclipse path. Then, they stitch them together for a continuous view as it crosses the United States. 

7.) Where can you get even more information and news?


So many places! You've probably noticed all of the NASA content. They have tons of information all over their website, specifically their Eclipse 2017 page, as well as their Facebook page and What's Up for August 2017 tumblr. These are also fantastic: Great American Solar EclipseAAS Solar Eclipse Across America, and Space.com,  Also keep up-to-date by following the Eclipse 2017 Facebook page.


Did I miss anything? If so, leave a comment.

And remember, have fun!



Friday, July 21, 2017

The Dermatology of Greyscale


Game of Thrones is back! *fangirl scream*

In honor of the show's return, I was poking around in the scientific literature for a fitting article. I found an interesting little note in a dermatology journal concerning "greyscale."

Greyscale (also known as "Prince Garin's curse or "grey death") is a relatively uncommon but fatal disease in Westeros. It typically affects children living in cold, damp climates but everyone is susceptible. It is characterized by hardened and calcified skin that feels stone-like and cracks as a result of the body's movement. Severely affected areas have a scaly appearance. In advanced stages of the disease, the skin further hardens and becomes mottled grey and black as it dies, giving it a stony appearance. In the final stages, the internal organs harden, eventually spreading to the brain and causing insanity. Greyscale is very fast to contract but slow to kill, often taking many years. During those years, as the infection spreads over the entire body, an infected person becomes known as one of the "Stone Men." Children have a slightly better chance of surviving an infection, but it is rare. Should a person survive the disease, they are immune from contracting it again but are left disfigured.

A short but entertaining piece in JAMA Dermatology discusses possible epidemiological aspects of greyscale. (note: may contain minor spoilers from this point on)

Greyscale is often compared to leprosy (Hansen's disease), a bacterial infection caused by Mycobacterium leprae. But greyscale differs in that it is spread by skin (or possibly object) contact and has no leonine facies, dermal plaques and patches, neuropathy, etc. Well, what do we know? First, we know of the case of Shireen Baratheon, daughter of Stannis Baratheon and child survivor of greyscale. She has lingering skin changes described by the article as "ichthyotic plaques in a somewhat Blaschkoid pattern limited to the left side of the face and body." We also know that the Stone Men have disseminated skin changes and are mentally unstable, with aggressive behavior. But perhaps the most interesting and telling case is that of Jorah Mormont. Following skin-to-skin contact with a Stone Man, Jorah developed a skin lesion within only a day.  Leprosy, and most other infectious agents, are not nearly this contagious. The article hypothesizes that greyscale may actually be a virus that is as contagious as smallpox. In Shireen, it presented like a genodermatosis, which is genetically based, perhaps like a mosaic form of epidermodysplasia verruciformis. In the end, the clinical data and pathology reports coming out of Westeros are thin. With this new season, perhaps we can further follow Jorah's disease progression and maybe his cure as well.


Lipoff, J.B. (2016) Greyscale - A Mystery Dermatologic Diseas on HBO's Game of Thrones. JAMA Dermatology. 152(8):904. DOI: 10.1001/jamadermatol.2015.5793


Details about greyscale and image via Game of Thrones Wiki.

Tuesday, June 20, 2017

Should You Ask a Question During Seminar?

There needs to be a box for "Do you need the seminar to end so you can refill your coffee?"
Of course, the answer to that is always "Yes."




Thursday, June 8, 2017

The Photosynthesis Song

I love this. Photosynthesis is pretty great.


Friday, May 26, 2017

The Ugliness Penalty: Does It Literally Pay to Be Pretty?


There are economic studies that show that attractive people earn more money and, conversely, unattractive earn less money. I’m pretty sure that I’ve heard something along those lines before, but I had no idea they were called the “beauty premium” and the “ugliness penalty.” How wonderful and sad at the same time. But while these seem like pretty commonplace ideas, there is no real evidence as to why they exist. A new paper published in the Journal of Business and Psychology tested three of the leading explanations of the existence or the beauty premium and ugliness penalty: discrimination, self-election, and individual differences. To do this, the researchers used data from the National Longitudinal Survey of Adolescent Health. This is a nationally representative sample that includes measurements of physical attractiveness (5-point scale) at four time points to the age of 29. People were placed into 5 categories based on physical attractiveness, from very attractive to very unattractive. They statistically compared every combination they could think of and came up with many tables full of tiny numbers, as well as some interesting results.

Discrimination

It is what it sounds like: ugly people are discriminated against and paid less. And it isn’t just from employers, it can also be from co-workers, customers, or clients that prefer to work with or do business with pretty people. Or it could be a combination, like an employer that hires someone pretty because they know that others will respond to them better. Because there is a monotonically positive association between attractiveness and earnings (an overly academic way of saying that one is linked to the other), it can be tested.

The results painted a somewhat different picture than you might expect. There was some evidence of a beauty premium in that pretty people earned more than average looking people. However, the researchers found that attractiveness and earnings were not at all monotonic. In fact, ugly people earned more than both average and attractive people, with “very unattractive” people winning out in most cases. So no ugliness penalty and no discrimination there. Good, we don’t like discrimination. Rather, the underlying productivity of workers as measured by their intelligence and education accounted for the associations observed. Basically, ugly people were smarter (and yes, IQ was a variable).

Self-Election

This occurs in the absence of discrimination. A person self-sorts themselves into an attractiveness group based on how attractive they perceive themselves to be and may choose their occupation accordingly. If a pretty person chooses an occupation that has higher earnings (or vice versa), then there is a positive association between attractiveness and earnings both across and within occupations.

Once again, the results were unexpected. The self-selection hypothesis was refuted. Ugly people earned more than pretty people. In fact, very unattractive people earned more than both regular unattractive and average looking people. This is where the researchers start calling this effect “the ugliness premium.” Good term.

Individual Differences

This one posits that a pretty and ugly people are genuinely different. Try looking at it in the context of evolutionary biology. Physical attractiveness is based on facial symmetry, averageness, and secondary sexual characteristics, which all signal genetic and developmental health. Many traits can be quantified very accurately with today’s computers. There are standards of beauty both within a single culture and across all cultures. Studies have also shown that attractive children receive more positive feedback from interpersonal interactions, making them more likely to develop an extraverted personality. If health, intelligence, and personality, along with other measures of productivity, are statistically controlled then attractiveness should be able to be compared to earnings.

Again, there was absolutely no evidence for either the beauty premium or the ugliness penalty. Rather, there was some support for the ugliness premium. Now keep in mind, this was not as much a this-higher-than-that, but more of a this-different-from-that type of hypothesis. So there actually is strong support that there are differences. There was a significantly positive effect of health and intelligence on earnings. Also, the “Big Five” personality factors – Openness, Conscientiousness, Extroversion, Agreeableness, and Neuroticism (or OCEAN…cute) – were significantly correlated with physical attractiveness. Pretty people were more OCEA and less N. This may be why looks appear to have an effect on earnings.


Overall, not what you thought it would be, huh? Me either. The importance of intelligence and education as it correlates with attractiveness would be an interesting next step. I wonder if it reflects the time at which these data were taken. We are seeing the Rise of the Nerds, where intelligence is outpacing beauty in terms of success. Had they analyzed data from another decade, would the ugliness penalty find support?


Kanazawa, S., & Still, M. (2017). Is There Really a Beauty Premium or an Ugliness Penalty on Earnings? Journal of Business and Psychology DOI: 10.1007/s10869-017-9489-6


image via Linked4Success

Friday, May 19, 2017

Friday, May 12, 2017

A Cuttlefish Clash: The Strongest, Stripeyist Guy Gets the Girl


I know what you’re thinking: “Why hasn’t she written about cuttlefish mating systems?” I understand, cuttlefish are ridiculously cool and you just need to know more about them. You are in luck as a brand new study has been published online about just that topic!

Cuttlefish are cephalopods, which are all predatory, marine animals that have at least eight arms, a siphon for jet-propulsion, and highly developed nervous and sensory systems (specifically the most sophisticated eye of all invertebrates). Those last characteristics make them highly intelligent, with complex learning behavior, to the point that many consider them to be “conscious.” Unlike other cephalopods, all of their hard parts (if any) are internal. That means all of their outside parts are soft, squishy and covered in color-changing skin. Their ability to change color is absolutely amazing, particularly in cuttlefish (just google ‘Flamboyant Cuttlefish’!). Located in their skin are tons of chromatophores (pigment filled bags) that expand or contract to reveal/hide their color. And it’s crazy-fast too. They can alter their appearance in as little as half a second! They use this color change for camouflage, courtship rituals, or just to show you how they feel about you interrupting them with your dive camera (a little personal experience with a mama octopus thrown in there).

Cuttlefish are in the clade Coloidea that also includes squid and octopuses, and a sister group to the Nautilus. They look like squid but have stouter bodies and a fin fringe that runs around their body that they undulate to move. They have separate sexes and an often elaborate courtship ritual. Should a female find a male worthy, she accepts his spermatophore (sperm packet), which he transfers to her with a specially modified arm (hectocotylus). Then the females will use the contents of this packet to fertilize their eggs and lay them in clusters.

Cuttlefish can be seasonal in their mating habits, with some species gathering in the hundreds to find their special someone. Where animals gather to mate, they also gather to strut their stuff. One of the ways they do this is through shear brawn. Basically, the strongest guy gets the girl. A study currently in press in The American Naturalist describes competition between male cuttlefish. Males compete vigorously for female mates. The researchers took a close look at the Common Cuttlefish (Sepia officinalis), a species “renowned for its visual capabilities, rapid adaptive camouflage, learning, and memory.” All those amazing qualities and yet oddly lacking in its ability to identify individual mates or rivals. Seriously, telling boy from girl is a challenge. This means that they must use a signal-response system to recognize each other. This system employs the use of intense zebra-stripe displays. Respond to a zebra with a zebra and you are male. If you don’t want to fight, darken your whole body (sign of alarm), ink and jet away. But extend your fourth arm, darken the skin around your eyes, and dilate your pupils and you know that shit is about to get real: inking, swiping, grappling, lunging, rolling, and biting. An all-out cuttlefish brawl.

A lot of this information is known from lab studies of cuttlefish, but how do they act in their natural environment. To test this, the researchers went to the Aegean Sea near Çeşmealtı, Turkey and filmed a bunch of cuttlefish. They brought the footage back to the lab to analyze mate guarding and fighting behaviors, frequencies of a series of agnoistic behaviors in individual males, and aggressive behaviors (e.g., bar room brawl scenario). Since it all starts with the zebra stripes, they also compared the intensity between males. They found a generalized sequence of events that correlated to the amount of aggression. For example, just a dark ring around the eye is low-level aggression, adding a dilated pupil ramps it up to medium-level aggression, intensifying the zebra pattern and arching and tilting the body ramps it up even more. The more medium- to high-level aggressive behaviors the more likely the male was to win. The researchers summarize it this way: “weak zebra banding, fourth arm extension, dark eye ring > dark eye ring with dilated pupil, dark face, strong zebra banding, inking > intense zebra display > swiping, grappling > biting, rolling.” This makes sense if you think about it. Fighting may result in injury and injury is costly, sometimes fatal. So you need to make sure you can win. The series of stages allow each male to assess both themselves and their opponent to see if an actual brawl is worth it.

Now, take what you’ve just learned and apply it to this video. It shows exactly the type of bout the authors describe. You may need to watch it twice, once to read the descriptions of what is going on and another to watch for the subtle differences described above. Can you see the color and eye changes?


Just imagine what we will find out as camera systems get faster. Considering the extremely fast rate at which cuttlefish are able to change their colors, it is very likely that we are missing a lot of the more subtle details in communications between males (and probably with females too). We’ll have to revisit this subject in the future.


Allen, J., Akkaynak, D., Schnell, A., & Hanlon, R. (2017). Dramatic Fighting by Male Cuttlefish for a Female Mate The American Naturalist DOI: 10.1086/692009


Learn more about Cephalopods at the University of California Berkeley’s Museum of Palentology and the Monterey Bay Aquarium

Image from the Monterey Bay Aquarium

Thursday, May 11, 2017

Tuesday, May 9, 2017

Wednesday, May 3, 2017

Gimme Your Lunch Money!: Feeding Behaviors in Hummingbirds

Ubatuba, São Paulo, Brazil; 9 October 2014 © Almir Cândido de Almeida
I just put out my hummingbird feeder this season. It didn’t take those little guys long to find it either. Now I’ve got their cute little bodies whizzing about all over the place. They need Yackety Sax to play as their soundtrack. But it got me to thinking about hummingbirds and to looking through recent papers for a good study. I came across one in Zoologia about the feeding behavior of hummingbirds in artificial food patches. Perfect.

First, a little background on hummingbirds. They belong to the family Trochilidae and are closely related to swifts. Males are typically more colorful that females, having highly reflective feathers on their chest and heads. Perhaps these birds are best known for their unique flying. They are able to produce power with both the down- and up-beat of their wing flap, getting 75 percent of their lift from their wings’ downstroke and the remaining 25 percent from the upstroke. This allows for both increased agility and sustained hovering ability. They are the only birds that truly hover and fly backwards. They also move those wings really fast: 60 times per second! So it is little wonder that they have among the highest metabolic rate among vertebrate animals.

Hummingbirds are specialized and consume predominately nectar. To collect enough nectar to maintain that high metabolism, they forage many flowers each day. But not all flowers are created equally. Their sugar concentration can vary between 20-25 percent. In order to get the most sugar-bang for their hover-buck, hummingbirds must select and protect the richest food patches in their area. Three behavioral strategies have been observed for foraging:

1) Dominance/territoriality – a bird will defend its flowers
2) Intruder/subordinance – a bird sneaks into other patches until it is kicked out
3) Trapline foraging – repeatedly visiting a set of plants in different patches without being territorial.

Often, a bird will perch near a good food source and let others know that it is theirs. But defending a territory can be up to three times more energetically expensive, so those flowers need to be really good.

The researchers conducted their study in Itacolomi State Park in the city of Ouro Preto, Minas Gerais, southwestern Brazil, in the Atlantic forest remnant. They created four artificial food patches, each patch containing a single sugar-water solution concentration of 5, 15, 25, or 35 percent. They observed the birds (using binoculars) for 3 hour stretches in the early mornings and late afternoon, recording all behaviors during that time. They looked at the time spent in each food patch and the behaviors of the birds (feeding, alert, vocalizing, expelling, fighting, frightening, expel attempt) in each patch. In this way, they could identify the birds’ strategies.

They found that the most-visited feeders were those containing the highest concentration of sugar. Five of the seven species observed fed more on the 25-35 percent sucrose feeders. But there was a difference in the frequency of visitations for different species. The Brazilian ruby (Clytolaema rubricauda, pictured above), Scale-throated hermit (Phaethornis eurynome), and Phaethornis spp. visited the 35 percent feeder more often. And the Brazilian ruby won most of the aggressive encounters with other hummingbirds, both total and in individual patches. This species often stood alert and fought more often, and even “stood impassive” when faced down by the Violet-capped woodnymph (Thalurania glaucopis). I wonder if they looked down their long little beaks at the other birds with a f*ck off attitude? What a badass...hmm, or a bully. The Violet-capped woodnymph visited the 25 percent patch more often, the White-throated hummingbird (Leucochloris albicollis) and Versicoloured emerald (Amazilia versicolor) visited the 15 percent patch more often, and the Glittering-bellied emerald (Chlorostilbon lucidus) was the one that less frequently visited the food patches. Interestingly, the Phaetornithinae applied a hide-and-wait strategy, where they would be chased away by the territorial bird only to hide in the shrubs, remain quiet, and return to the feeder after the dominant bird left the area. Sneaky sneaky. The time spent feeding was found to be correlated with aggressive behaviors and also with body size. Big birds, big appetites, big aggression. The subordinate species chose resources depending on the presence or absence of the dominant species, preferring patches that were not guarded. This may be why they were seen in lower concentration sugar patches more often.

Those itty bitty birds can pack some serious aggression. I guess it isn’t really surprising after seeing all of the chasing that goes on around my feeder. Yackety Sax remains appropriate.

Lanna, L., de Azevedo, C., Claudino, R., Oliveira, R., & Antonini, Y. (2017). Feeding behavior by hummingbirds (Aves: Trochilidae) in artificial food patches in an Atlantic Forest remnant in southeastern Brazil Zoologia, 34, 1-9 DOI: 10.3897/zoologia.34.e13228


If you would like to put out your own hummingbird feeder, I recommend this kind because it is simple, inexpensive and does a great job.



The important part is the big red flowers with yellow centers. Hummingbirds really hone in on those color ques. Do NOT use honey in your feeder! And forget the red dye, if your feeder has red color on it then that is plenty to attract the hummingbirds.

Here is a nice and simple recipe to make your own hummingbird food:

¼ cup granulated sugar
2 cups water

Mix the ingredients in a small saucepan. Bring to a boil. Boil for a few minutes or until all of the sugar is dissolved. Let cool to room temperature. Whatever doesn’t fit in the feeder can be stored in the refrigerator.

Increase the recipe as needed, it's a 1:4 ratio of sugar:water

Change the solution in the feeder every 3 days, sooner if it is really hot outside. Make sure to rinse the feeder each time it is refilled. Scrub away any growths (fungi, etc.) as needed.


Brazilian Ruby picture via The Cornell Lab of Ornithology
Feeder image via World of Hummingbirds

Wednesday, April 26, 2017

Whole New Worlds

What happens when you mix the music of Aladdin with astronomy? Something pretty wonderful:


Tuesday, April 18, 2017

Constance and Nano: Engineering Adventure!


The Society of Women Engineers (SWE)'s has the SWENext program , which offers great resources and outreach for students through the age of 18. They hold engineering events designed for girls, provide scholarships, hold events to meet women engineers, have cool engineering projects, and great contests.



One of their newer outreach endeavors is "Constance and Nano Engineering Adventure!" This is a comic book about friends Constance and Nano and their engineering adventures, solving problems with science, engineering, technology and math! You can even download the first issue for free HERE.


Wednesday, April 12, 2017

Flyfocals: Vision and Vectors Help Hunting Robber Flies

Image credit: Thomas Shahan

Robber flies (Asilidae family) are not your typical house flies. They are small, predatory insects that feed on a vast array of other arthropods. While they are small in size (10 times smaller than a dragonfly), these guys are serious hunters. For example, Mallophora omboides is known as the “Florida bee killer” for its taste for honey bees. Other robber flies hunt down wasps, dragonflies, spiders, or grasshoppers, just to name a few. Perhaps almost as impressive as the types of prey is how they are subdued. Typically, robber flies will perch out in an open sunny place and wait, seizing their prey in flight and injecting it with neurotoxic or proteolytic enzymes that both immobilizes it and liquefies its insides.

A recent study in Current Biology took a closer look at the robber fly’s “aerial attack strategy.” The authors focused on the genus Holcocephala, a group native to the Americas. Let’s start by going over something you know about but probably never realized had an actual term: constant bearing angle (CBA) strategy. Initially, I tried to describe this just using text, but it is really best visualized with the help of a supplemental graphic from the paper.

Figure S1 from Wardill et al. (2017). Diagram showing how the constant bearing angle strategy (CBA) and proportional navigation can be used to intercept targets. It looks like an eye, but you are actually looking down on the "Human" and seeing the top of the head (black) and shoulders (white). 
Visualize this: You are walking along and ahead of you a ball is rolling along the ground from your left. But you decide that you want to get to the ball before it would intercept your path. If you want to catch the ball you can’t run straight for where you see it or it will have rolled past that spot before you get there. If you want to intercept that ball while it is still on your left, you will technically have to turn to backward, changing your “bearing angle.” You must anticipate where it will be and run in a straight line to that spot. This line is a “parallel range vector.” There are several of these vectors, depending on when you choose to change course.

The study considered whether the flies were using this CBA strategy to catch their prey. To do this, the researchers went out to a field and hung up a big white sheet as a backdrop for their high-speed video cameras. Next, they set up their “fly teaser,” a custom made plastic frame that housed a stepper motor and several pulleys to move taut fishing line. This allowed for precise, computer controlled movements of the beads they attached to the fishing line. When a robber fly perched on a blade of grass in their study area, they “teased” it with a bead (a.k.a. dummy prey item for the fly). They included several variations including bead size and direction. They recorded the fly with two synchronized cameras running at 1000 fps to get a 3D view of the attack. For each attack video, they analyzed the frame at which the flies started to take off and until it began a terminal deceleration on final approach of the target. Then: measure, measure, measure, math, math, math.

They found that the flies were fairly consistent with the CBA model. If they decelerated or reversed the bead during the attack, the robber flies compensated, actively keeping the range vectors parallel. One unexpected finding occurred in cases where the bead moved in front of the fly and it took off with a head-on collision course. They found that the fly still intercepted the bead while flying at a backward angle, meaning that the latter part of its trajectory was distinctly curved. When they took a closer look, the found the results to reflect a “lock-on” process “during which the fly has a new heading and the speed is fixed to a value slightly higher than that of the prey.” This lock-on strategy has not been described in any other flying animal. The flies were able to compensate for unexpected changes in the target’s velocity and uncertainties in the location, size, and speed of the target.


Adapted from paper's graphical abstract
This type of hunting relies very heavily on vision. So each robber fly was captured for later, high detailed analysis of the head and eyes. It is important to remember that insects have compound eyes. Repeating units (the ommatidia, which have hexagonal faces called facets) that make up the eyes function as separate receptors that, when put together, assemble view of the environment. The researchers measured several parts and angles within the eyes, and once again math, math, math. This revealed the ommatidia in the front, center portion of each eye (colored red in the picture) to be nearly double the size of those in other areas, have extended focal lengths and smaller receptors. This means that the flies can reduce diffraction, focus incident light, and optimize resolution in this area. This results in a frontal fovea, or area within the eye that provides greater visual acuity than the rest of the eye. Sort of like the embedded lens of bifocal glasses; while that is an incredibly simplified way to look at it, it tells you a lot about how the flies might strategize prey capture. Also, they could be judging distance using stereopsis. This is when they use both eyes in combination to depth and 3D structure. The authors sum things up nicely, so I'll leave it in their words: "[It is kind of amazing the] accurate performance that a miniature brain can achieve in highly demanding sensorimotor tasks."

Interested in more details? Here’s a video summary put together by the researchers:

video




Wardill, T., Fabian, S., Pettigrew, A., Stavenga, D., Nordström, K., & Gonzalez-Bellido, P. (2017). A Novel Interception Strategy in a Miniature Robber Fly with Extreme Visual Acuity Current Biology, 27 (6), 854-859 DOI: 10.1016/j.cub.2017.01.050


Read more about robber flies at University of Florida's Featured Creatures page.

Wednesday, April 5, 2017

The Universe is Your Sandbox


Lately I've been catching up on The Weekly Space Hangout podcast. A few weeks ago, they featured an interview with Dan Dixon, a developer of Universe Sandbox. This is an incredibly cool, scientifically accurate, interactive space and gravity game/simulator.

"Create and destroy on an unimaginable scale... with a space simulator that merges real-time gravity, climate, collision, and material interactions to reveal the beauty of our universe and the fragility of our planet."

Want to add a moon or two to a solar system and see how those moons will be ripped apart by a planet? How about seeing what happens when you fling planets into or out of a solar system? What about modeling Earth's climate, watching sea ice grow and recede based on the planets tilt? Oh! And go ahead and terraform Mars while you are tinkering with climates. The scenarios of creation and destruction you can do are endless!

Perhaps most importantly, it uses real science, real physics. And it runs on your home computer. The latest version even has VR mode. It only costs $24.99 (USD), which, for a video game of this complexity is pretty good.

Check it out:



A moon colliding with Earth.

Orbiting bodies and their trails colored by their velocity.

A supernova within our solar system.

Neptune pulling apart Saturn's rings.


All images from Universe Sandbox.

Tuesday, March 14, 2017

Thursday, March 9, 2017

Women of Science

This is a wonderful video about some important women of science and the sexism that they faced then as well as today.


Monday, March 6, 2017

Dart Art: Science and Nature

I know Kevin Dart's work through his movie art (e.g., Interstellar). This is his Science and Nature series, which features prints that focus "on the wonder that is space and our surroundings."

You can see more of his art at his tumblr page.










SCIENCE & NATURE - Teaser Trailer from Chromosphere on Vimeo.

Thursday, March 2, 2017

Women of NASA Legos!



Legos! I don't know about you, but I love all things Lego. When Lego goes sciency, I love it even more. Now, five female NASA pioneers will soon me immortalized in Lego form in the new Women of NASA set created by Maia Weinstock, a science editor and writer at MIT news. It beat out 11 other projects in a Lego Ideas competition. And with the recent success of the movie "Hidden Figures," this set is sure to be a hit.

Margaret Hamilton
The set includes figures of:

  • Margaret Hamilton - A computer scientist that worked at MIT under contact with NASA in the 1960s. She developed the on-board flight software for the Apollo missions and was awarded the Presidential Medal of Freedom for her work in the Apollo 11 moon landing. She poplarized the modern concept of software.



Katherine Johnson
  • Katherine Johnson - A  mathematician and space scientists that is best known for calculating and verifying trajectories for the Mercury and Apollo programs. She is one of the women portrayed in the movie Hidden Figures.






Nancy Grace Roman
  • Nancy Grace Roman - A chief astronomer for NASA and one of the first female executives at NASA. She is known as the "Mother of Hubble" because she was instrumental in the realization of the Hubble Space Telescope. She also developed NASA's astonomy research program.





    Sally Ride
  • Sally Ride - Best known as the first American woman in space (1983), she was also a physicist. She later focused on education, founding an educational company focusing on encouraging children, especially girls, to pursue the sciences.







  • Mae Jemison - Best known as the first African-American woman in space (1992), she's also a mediacal physician and an entrepreneur. She established a company that develops new technologies and encourages students in the sciences.





It also includes a desktop frame that displays the figures and their names as well as vignettes detailing their accomplishments.



Keep up to date with this at the Lego Ideas Project Page for Women of NASA



Read more at:

Tuesday, February 28, 2017

Rap Battle: Mitosis vs. Meiosis

We all love a good rap battle. Watch mitosis take on meiosis!


 

Friday, February 24, 2017

Symbiote Separation: Coral Bleaching and Climate Change


It’s been a while since I’ve broken down some studies for you, so I took on a big one.

I’m sure you’ve heard of coral bleaching. What is it? Why does it happen? Why does it matter? To start off, you need to know a little bit more about the individuals that make up a coral head (fan, whip, etc.): the polyp. Coral polyps look like tiny plants but are actually tiny animals (less than ½ an inch in diameter). They produce calcium carbonate to create a protective shell or skeleton that, when thousands are living together, make up what you see as a single coral head. Really, only the outer-most layer of a coral head is actually alive (yes, they build their houses on top of the skeletons of their ancestors). Lots of individual corals make up a reef. Polyps have stinging cells (nematocysts) on their tentacles that capture any prey that swims a little too close. But a polyp does not live alone inside of its skeleton-house; it is actually in a symbiotic relationship with dinoflagellates (a.k.a. marine algae) called zooxanthellae (zo-o-zan-THELL-ee). Zooxanthellae live inside the tissues of the polyp and photosynthesize, passing some of the energy they make to the polyp. They get a place to live and the polyp gets some energy, it’s a win-win. And, it is the zooxanthellae that give the corals much of their color.


When the coral gets stressed, it expels the zooxanthellae, causing them to turn completely white. Not dead, but very stressed and more likely to die. This is coral bleaching. All sorts of things can stress a coral and cause them to eject their zooxanthellae: temperature, light, tides, salinity, or nutrients. A polyp has cemented itself in its skeleton-house so it isn’t able to relocate when conditions change. Coral reefs are one of the most diverse ecosystems on the planet, definitely in the oceans. Coral serves as both food and/or shelter for many other species, up to ¼ of all ocean species. And their location means they protect shorelines too. That is a lot of responsibility.





Now let’s look at those stressors. Remember middle school chemistry? Yeah, me neither. Here’s a little refresher: water reacts with carbon dioxide to make carbonic acid (H2O + CO2 = H2CO3). Rising atmospheric carbon dioxide (yes, we’re talking climate change here) both increases surface water temperature and makes water more acidic. That’s two stressors, y’all. And more than 30 percent of human emitted CO2 gets taken up by the oceans. A paper published by Anthony et al. (2008) in PNAS did a nice experiment looking at what happens to different coral species when the ocean acidifies and/or warms. They collected three of the most important “framework builders” in Heron Reef in the Indo-Pacific and transferred them to lab aquaria: Porolithon onkodes (common crustose coralline algae [CCA] species), Acropora intermedia (a fast growing, branching species), and Porites lobata (a massive species). Next, they used a custom-built CO2 dosing (bubbling) and temperature control system to test different acidification and temperature regimes that simulate doubling and 3- to 4-fold CO2 level increases as projected by the Intergovernmental Panel on Climate Change (IPCC). Then, they waited, they watched, and they took pictures for 8 weeks. From these digital images, they measured the amount of color and reduction in luminance of the corals. They also measured net rates of photosynthesis, respiration and calcification.

They found that increased CO2 (i.e., acidification) led to 40-50 percent bleaching in Porolithon and Acropora. For both of these species, the effect of increased CO2 on bleaching was stronger than the effect of temperature. Porites was less sensitive to increased CO2 alone, but was most sensitive in both stressors. High temperature amplified the bleaching by 10-20 percent in Porolithon and Acropora and 50 percent in Porites. In Porolithon, increased CO2 lead to a severe decline in productivity and calcification that was exacerbated by warming. Acropora’s productivity actually maximized with intermediate increases in CO2, but dropped at higher levels. Porites's productivity dropped with high CO2 but not like that of the Acropora. These species had similar calcification responses to each other, each much less than Porolithon. Overall, the authors proposed that CO2 induces bleaching through its impact on photoprotective mechanisms. Porolithon was the most sensitive to acidification, which is concerning because it is a primary reef-builder and serves as a settlement cue for invertebrate larvae (including other corals).

A very recent study by Perry and Morgan (2017) in Scientific Reports zoomed out to look at corals at a large scale. They looked at magnitude of changes that followed the El Niño/Southern Oscillation (ENSO)-induced Sea Surface Temperature (SST) warming anomaly that affected the central Indian Ocean region in mid-2016, sort of a natural warming experiment. The ENOS-induced SST warming was above the NOAA “bleaching threshold,” defined as the point where SST is 1°C warmer than the highest monthly mean temperature. To do this they went to reefs in the southern Maldivian atoll of Gaafu Dhaalu, ran transects (basically, a line along which you measure stuff), and collected data on coral mortality, substrate composition, reef rugosity (a measure of complexity), and gross carbonate production and erosion. Then they determined carbonate budgets for the 3-dimensional surface of the reefs (there are equations…I won’t go into it…you’re welcome).

They found extensive, overall coral mortality - over 70 percent. This was mostly driven by branching and tabular Acropora species (remember them from the last study?), which declined by an average of 91 percent! All of this coral death resulted in a decline in the net carbonate budgets. This decline reflected both reduced coral carbonate production and increased erosion by parrotfish as they graze on the algal film that grows on coral rock. Pre-coral bleaching, carbonate production was dominated by branching, corymbose and tabular species of Acropora; post-bleaching production by non-Acropora increased, with massive and sub-massive taxa (e.g., Porites species) more than doubling. Together, carbonate budgets were reduced by an average of 157 percent! All of this equates to a rapid loss in coral cover, growth potential, and structural complexity. The overall impact of the carbonate budget was profound and has major ecological implications. These habitats have gone from a state of strong growth potential to one of net framework erosion and breakdown; basically, the reefs are eroding faster than they are growing. And it may take 10-15 years for a full recovery, depending on the frequency of similar anomalies.

So what’s the take-away from all of this? Corals are sensitive to their environment, but not all species of corals respond equally. Climate change is a huge factor in health and recovery of coral reefs, and steps need to be taken soon if we want to keep these little guys and the phenomenal habitats that they create.

Here are the studies:

Anthony KR, Kline DI, Diaz-Pulido G, Dove S, & Hoegh-Guldberg O (2008). Ocean acidification causes bleaching and productivity loss in coral reef builders. Proceedings of the National Academy of Sciences of the United States of America, 105 (45), 17442-6 PMID: 18988740

Perry CT, & Morgan KM (2017). Bleaching drives collapse in reef carbonate budgets and reef growth potential on southern Maldives reefs. Scientific reports, 7 PMID: 28084450


Also check out the NOAA Coral Reef Conservation Program and The Smithsonian Ocean Portal for Corals


Images from (in order of appearance): NOAA Coral Reef Information SystemSmithsonian Ocean Portal, and NOAA Ocean Service

Tuesday, February 14, 2017

Like a Tardigrade, My Love For You Will Never Die

How could I pass up a Valentine's Day without posting some wonderfully sciency V-day cards and comics?

From: Tiny Snek Comics

via FB; credit unknown

From: Sketching Science


From: National Geographic Channel


From: Trust me, I'm a "Biologist"; comic credit: Nick Uhlig


From: Trust me, I'm a "Biologist"; comic credit unknown



From: Entomology Memes

From: Fake Science


From: The Upturned Microscope



From: Gomer Blog


From: Science Friday


From: Science Friday



From: xkcd






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