Zebra finches practice singing for the ladies

The male zebra finch (Taeniopygia guttata) learns to sing in private before performing for a female audience, according to Satoshi Kojima and Allison J. Doupe from the University of California, San Francisco. In addition, juvenile male finches seem to step up the quality of their singing, despite their immaturity, when in the presence of potential mates. As described in the blog Talking Science, part of National Public Radio’s Science Friday Initiative, “Male finches, by the time they are sexually mature, typically know two different forms of song: undirected, which is performed in isolation, and directed, which is performed for a female audience. Young males learn undirected song first, which characteristically sounds immature and is of variable quality. As adults, they become experts in directed song, a talent they refine specifically for the purpose of courting females.” As the researchers reported in the Proceedings of the National Academy of Sciences study, the juveniles, when performing for females, seemed to focus on the best parts of the songs that they practiced in private. Kara Rogers wrote in Talking Science, “The discovery reveals that the undirected song of young male finches disguises the actual extent of the birds’ song-learning capabilities…” In other words, despite their inexperience, immature male finches were able to sing at the level of mature finches in the appropriate social conditions: When there was a chance to  mate. Read about the zebra finch genome in Nature or take the songbird call challenge at enature.com. Photo Credit: Patricia van...

Read More

Wet or dry: Butterflies reverse sex roles in extreme seasons

In the case of the African butterfly Bicyclus anynana, females develop ornate wings and court males if they spend the larval stage in a dry, cool environment. The reverse occurs, according to Kathleen Prudic from Yale University and colleagues, when the butterflies are exposed to wetter, warmer environments. “As expected, female Bicyclus anynana in warmer moister conditions that mimic the wet season in the native African range were more likely to mate with males with ornamented wings,” explained a Yale University press release. “However, the roles were reversed in cooler drier climates. Females played the role of suitors and flashed their eye spots to choosy males. When scientists studied the wing spots, which reflect light in the UV range, invisible to humans, they found they were brighter in the courting females relative to the males of that same season, or relative to females raised in the hotter season.” In a study published today in Science magazine, Prudic and colleagues suggested that the reversal is brought about by the environmental conditions. When transferring sperm, the male butterflies also administer nutrients, increasing the females’ chances of surviving the harsh conditions of a warm, dry season. Therefore, it is in the best interest of the female butterflies to attract males for their supply of nutrients, whereas males will be more selective in choosing females since they are limiting their own chances of survival by mating. As a result, the females that flash their showy spots are more likely to be chosen. Photo Credit: South African...

Read More