Insect Navigation: Dung Beetles and the Starry, Starry Night

Panoramic image of the Milky Way.
European Southern Observatory/S. Brunier. Creative Commons.

Just as sailors once followed the stars to distant lands, dung beetles can use starry skies to navigate, according to an article published in the January 23 issue of Current Biology.

A research team led by Marie Dacke, a biologist at Sweden’s Lund University, conducted their experiments in the Johannesburg planetarium, which was fully darkened as well as illuminated with projections of the Milky Way and other stars.

As reported here in ScienceNews,

Dung-rolling insects are excellent for studying navigation because they collect their prized food source and single-mindedly roll it as directly as possible away from competitors and predators. Putting the beetles in weird get-ups during experiments doesn’t deter them. “They are so attached to their dung balls,” Dacke says, “that under all circumstances they just want to roll the ball in a straight line.”

via Dung beetles steer by the Milky Way | Zoology | Science News.

Dung beetle (Circellium bacchus.) There are thousands of species of dung beetles. Scarabaeus satyrus was the species used in the starlight experiment.
By Kay-Africa. Wikipedia Commons.

Estrogenic: Consumption of Certain Plants May Be Linked to Aggression in Monkeys

Red colobus monkeys in Uganda.
Image by Duncan (Wellington, NZ). CC By-S.A. 2.0.

Munching on large amounts of phytoestrogen-rich leaves from the Milletia dura tree appears to alter hormone levels and behavior among red colobus monkeys, according to a study published in the journal Hormones and Behavior.

Studying a group of male red colobus monkeys in Uganda, scientists from the University of California-Berkeley found that levels of estradiol and cortisol rose with seasonally higher consumption of estrogen-like compounds. In addition, the monkeys fought and mated more, and indulged less in the social-bonding activity of grooming.

“It’s one of the first studies done in a natural setting providing evidence that plant chemicals can directly affect a wild primate’s physiology and behavior by acting on the endocrine system,” said study lead author Michael Wasserman, who conducted the research as a graduate student at UC Berkeley’s Department of Environmental Science, Policy and Management. “By altering hormone levels and social behaviors important to reproduction and health, plants may have played a large role in the evolution of primate — including human — biology in ways that have been underappreciated.”

via Eating estrogenic plants alters hormones in monkeys, may increase aggression and sex.

Researchers warned against assigning too much influence to phytoestrogens, however, explaining that diet is just one factor in behavior. Others include the hormones already produced inside the body as well as the amount of competition for food and mates.

Elephants: Around the Waterhole with Field Biologist Caitlin O’Connell-Rodwell

Caitlin O’Connell-Rodwell in Etosha National Park.
Photograph by Tim Rodwell.

 
When it’s time to leave the waterhole, African elephant family groups have a special way of announcing their departure. “We call it the ‘let’s go’ rumble,” explains Caitlin O’Connell-Rodwell, a Stanford University scientist who has been studying elephants in Namibia’s Etosha National Park for 20 years. First comes the low-frequency call of the matriarch, followed by a series of close or overlapping rumbles from other high-ranking females. “What you get is a call that’s at least three times the size of the original call,” O’Connell-Rodwell says. “It’s as if they need the motivation of this call to action.” Her study of these departure vocalizations recently appeared in the journal Bioacoustics.

But the scope of O’Connell-Rodwell’s research is larger (one might say elephantine): Her interests extend from seismic communication to wildlife conservation to the effects of the environment on elephants’ social structure. “There are a lot of different questions we have, because elephants are long-lived social animals,” she says. “It takes years to find particular social patterns.” Hoping to learn as much as possible about the elephants without disturbing them, O’Connell-Rodwell and her colleagues have set up a solar-powered camp at Mushara waterhole. 

O’Connell-Rodwell is also co-founder of Utopia Scientific, a nonprofit research and education organization, as well as the author of three books, including The Elephant’s Secret Sense: The Hidden Life of the Wild Herds of Africa. Here are a few glimpses of her work among the elephants of southern Africa:

You Talking to Me?

The waterhole is a great place to see the social behavior of elephants, as shown in another recent study by O’Connell-Rodwell in Ethology, Ecology, and Evolution. In a dry year, male elephants appear to know their place in the social order, following a kind of water-hole etiquette. “A lower-ranking elephant will typically stick his trunk inside the dominant bull’s mouth, and then step away as if to say, ‘I’m just going to drink over here where it’s really salty,’” O’Connell-Rodwell says. (“Elephants use their trunks like people use handshakes–as a greeting, a sign of respect, or appeasement.”)

Studying waterhole behavior, O’Connell-Rodwell found that elephants form linear dominance hierarchies in years with low rainfall. “When there are minimal resources, you have to have more order to prevent chaos,” she says. “Everyone knows where they stand, so there is less fighting and less stress.” Acts of affiliation, like the trunk-in-mouth described above, are more common than aggression.

But during wet years, things can get a little surly. O’Connell found younger bulls to be more aggressive than affiliative. (Aggressive behaviors can include anything from charging another elephant to flaring the ears.) “You don’t need to kowtow to the dominant [bull] when you can drink anywhere,” she says. “There is a lot more aggression when there is uncertainty in the ranking.”

Bulls in a Rush

When male elephants break out of the protected borders of the Etosha National Park, they often wind up in places where they’re unwanted. This puts them at risk of getting shot by humans. Concerned about the conservation of this sensitive species, O’Connell-Rodwell has experimented with one promising way of getting bulls to return: broadcasting a recording of an estrus call.

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Cystic Fibrosis: From sea sponges, a possible treatment

Sea Sponge
By Dimitris Siskopoulos. Creative Commons.

 

 

A genetic defect that is responsible for most cases of cystic fibrosis appears to be correctable by a compound found in sea sponges, according to this report on the research website Futurity. A research team led by David Thomas, of McGill University, identified the sea-sponge chemical latonduine as a promising candidate for treatment of this life-threatening disorder. Results appear in the journal Chemistry and Biology.

Birdsong: There’s rhythm & news in this research project

Inca Dove. This bird species’ coos (and dozens more) have been converted into musical notation.
Copyright William F. Walker, http://www.birdwalker.com

When Nat Wheelwright listens to birdsong, he hears information—what a bird is communicating to a potential mate, rival, or eavesdropper. Robby Greenlee hears colors, rhythms, and melodies. They may not be birds of a feather, but the two Bowdoin College professors—one an ornithologist and the other a composer and music theorist—are teaming up to transcribe and analyze a variety of birdsongs. In the process they hope to uncover new evolutionary and musical insights.

To launch their project this past summer, they enlisted John Butterworth, a Bowdoin student and jazz saxophonist, to transcribe into musical notations more than 50 dove and pigeon coos from recordings contained in the vast digital collection of the Cornell University Lab of Ornithology. They eventually hope to move on to other bird species, such as Baltimore orioles and brown creepers, but they wanted to start with relatively simple vocalizations. “It’s extremely difficult to transcribe, because birds do such complex things,” Greenlee says.

An American naturalist named F. Schuyler Mathews may have been the first to attempt to put birdsongs into western notations in his 1907 guide, Field Book of Wild Birds and their Music. “He gave up when he got to the bobolink because it got way too complicated,” Wheelwright says. “His biology [in this book] is pretty bad, and he didn’t get the ecology,” Wheelwright says. “I think because it was a failed experiment in terms of being useful scientifically, it gave transcription to western symbols a bad name. I’m not aware of anyone who’s done it since.”

But Wheelwright and Greenlee saw a need for their transcription project after co-teaching a popular course called “Bird Song, Human Song,” which explored similarities in both kinds of music. Students learned everything from the mechanics and endocrinology of sound production to an appreciation for how the mourning dove’s syncopated coos match the refrain from The Beatles’ “She Loves You.”

“In that class we were asking more questions than we could answer,” Greenlee says. “We realized that nobody had explored this from a scholarly or academic perspective,” adds Wheelwright. “I’m not really aware of a collaboration like this between a musician and a biologist.”

Click here for a link to a recording of an Emerald Dove (Chalocophaps indica) from the Macaulay Library at the Cornell Lab of Ornithology.

Below is the Emerald Dove transcription by Greenlee, Wheelwright, and Butterworth:

Musical notation based on Emerald Dove. Greenlee notes: “”Meter is 4/4, and pitches are approximately G-F#-G, or later in the coo, G-G-Ab. Most notable is the use of articulation (a short note, indicated by a dot above the note) to assist in establishing a meter.”
The top figure is an oscillogram and shows amplitude (loudness) of different notes. The one below, aligned in time, is a sound spectrogram or sonogram, showing frequency (pitch), including harmonics and other overtones (which give a sound its distinctive timbre).

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Botany Q & A: All Chris Martine is Saying … Is Give Plants a Chance

Whenever my four-year-old comes across a picture of a baby animal—any animal, even a beady-eyed, tongue-flicking rat snake breaking out of its shell—she responds with an Awwwww. She even wanted to make a home for the slug we encountered on the sidewalk the other day, proclaiming, “It’s so cute.” Like many kids, she’s obsessed with animals. Christopher Martine doesn’t mind people of any age fawning over fauna, but he thinks it’s time that his own field, botany, gets a little love, as well. That’s what has led the Bucknell University biology professor to create the video series, Plants are Cool, Too!

“One of the missions here is to sort of spread the word that the plant kingdom is a really important driver of all the processes that life on Earth depends on, but not do that in a way that’s sort of stale and people roll their eyes and say yeah yeah yeah,” Martine says. Instead, he’s using what he calls a “guerilla botany” approach to “draw people in with the coolest stories about plants [and] also to highlight the person or people doing the botanical research.”

In the second and most recent episode, which has been posted on YouTube, Martine travels to the fossil beds of Clarkia, Idaho, to look at 15 million-year-old leaves preserved between layers of rock. Then he interviews a group of University of Idaho scientists who have been studying the leaves and working to prove that it’s possible to extract DNA from them. (He also eats a baked potato, which hopefully wasn’t quite so old.)

“That’s kind of a controversial idea that the DNA from those specimens can actually be accessed and sequenced,” notes Martine. “Not every scientist actually believes it’s even possible to extract DNA that old. This would really set back the clock for how far back we’ve gone with DNA technology.”

Martine talked to me recently about his hopes for the video project: Continue reading

Ants: Enslaved workers revolt in their masters’ nests

Temnothorax longispinosus
April Nobile / © AntWeb.org / CC-BY-SA-3.0

 

Don’t ant-agonize Temnothorax longispinosus. When the worker ants of this species are enslaved by the parasitic Protomognathus americanus, they fight back, according to this report in ScienceBlog, featuring the research of Dr. Susanne Foitzik of Johannes Gutenberg University Mainz in Germany:

These ants become slaves when workers from the slave-making ant colony attack the nests of the host species Temnothorax longispinosus, kill the adult ants, and steal the brood. Back in the masters’ nest, which can be located in hollow acorns, nutshells, or twigs, the brood care behavior of the emerging slave workers is exploited to the advantage of the slavemaker species. As Susanne Foitzik and her work group have shown, the enslaved worker ants feed and clean the larvae, thereby raising the offspring of their social parasite – but only up to a certain point.

“Probably at first the slaves cannot tell that the larvae belong to another species,” explains Foitzik. As a result, 95% of the brood survives the larval stage. But the situation changes as soon as the larvae pupate. “The pupae, which already look like ants, bear chemical cues on their cuticles that can apparently be detected. We have been able to show that a high fraction of the slavemaker pupae are killed by slave workers.” The pupae are either neglected or actively killed by being attacked and torn apart. Several slaves at once may assault a pupa, which is unable to move or defend itself during the pupal stage and is also not protected by a cocoon.

via Slave rebellion is widespread in ants | ScienceBlog.com.