Research News 2009
11 14 09 How the Club-winged Manakin got its Call
On Quirks & Quarks, Bob McDonald interviews Kim Bostwick, an ornithologist at the Cornell University Museum of Vertebrates who studies the Club-winged Manakin, Machaeropterus deliciosus. The male Manakin produces its call by vibrating its wings together over its back. Now Bostwick has determined exactly how tapping feathers together produces a high-pitched note.
Q&Q: Singing Wings (includes links to video)
ACP: Neotropical Bird “Sings” With Wings (Bostwick’s earlier study)
“Resonating feathers produce courtship song,” (Free full text from Proceedings of the Royal Socitey B)
10 31 09 Red Squirrel Predator Call
On Quirks & Quarks, Bob McDonald interviews Shannon Digweed, of Grant MacEwan University in Edmonton, who studies squirrel calls. Red squirrels (Tamiasciurus hudsonicus) have two distinct calls, but unlike some other mammals, they do not use these calls to distinguish different kinds of predators. Instead, the call indicates the duration of an intruder alert, whether the intruder be a predator or another red squirrel.
Q&Q: Two-Alarm Squirrels (includes links)
ACP: Vervet Monkeys (classic study of predator alarm calls)
ONH: Olympic Marmot Call (Digweed mentions marmot calls in the interview.)
05 04 09 Do-not-discard signal for ants
Chemical compounds signal that an ant is alive and prevent coworkers from carrying it away to the colony graveyard, researchers have found. Previous studies have asserted that ants are cued to remove dead colleagues from the colony because of the buildup of decomposition products in the corpse. Dong-Hwan Choe and colleagues, however, assert that the disposal squad acts within one hour of the death, well before chemical products of decomposition could plausibly emanate. The researchers found that chemical cues for removal are always present, but are repressed by other chemical compounds that dissipate quickly after death among Argentine ant workers, Linepithema humile.
“Signs of life: Chemical signals associated with life inhibit necrophoresis in Argentine ants,” Dong-Hwan Choe, Jocelyn G. Millar, Michael K. Rust, PNAS,
05 03 09 Zebra finches Reestablish Wild-type Song
Among zebra finches, variations in songs are commonly found in different geographical locations. In the wild, young male zebra finches develop their individual singing styles by imitating adult males. Isolated males devleop songs that differ markedly from the wild-type song.
Olga Fehér and colleagues isolated a group of young zebra finches before they were exposed to the adult song, then allowed the finches to establish a new colony. The next generation imitated the isolated adults, but they had distinct differences in their songs. In three to four generations, the isolated colony’s songs evolved to more closely resemble that of wild-type finches.
“De novo establishment of wild-type song culture in the zebra finch,” Nature, 03-May-2009 (AOP), Olga Feher, Haibin Wang, Sigal Saar, Partha P. Mitra, Ofer Tchernichovski
CCNY Press Release
ACP: Learning to Sing
04 15 09 Darwin’s Legacy Stanford University
In 2008, Stanford University offered a joint undergraduate/continuing education course called Darwin’s Legacy. The whole class is excellent.
The fifth meeting features Peter and Rosemary Grant, who study Darwin’s finches. Rosemary’s talk, which begins about minute 48, is a fascinating explanation of bird song as a barrier to hybridization, and what happens when a male finch learns the “wrong” song.
Darwin’s Legacy on iTunes
ACP: Learning to Sing
01 31 09 Tiger Moths Jam Bat Sonar
While most moths merely try to escape when they detect a bat’s ultrasound, some Tiger Moths talk back. In a recent case, the moths, Bertholdia trigona, make so much ultrasound that William Conner and colleagues think the moth is jamming the bat’s sonar.
Science News article, with links and video.