Effects of a social cue on reproductive development and pre-alternate molt in seasonally breeding migrant and resident female songbirds (Zonotrichia leucophrys) [RESEARCH ARTICLE]

Helen E. Chmura, Simone L. Meddle, John C. Wingfield, and Thomas P. Hahn

To time reproduction optimally, birds have evolved diverse mechanisms by which they respond to environmental changes that help them anticipate and prepare for the breeding season. While residents initiate reproductive preparation and breed in the same geographic location, migrant birds simultaneously prepare for breeding and migration far from their breeding grounds. As a result, it is hypothesized that migrant and resident birds use environmental cues differently to prepare to breed and that there is adaptive specialization in mechanisms regulating reproductive preparation. Specifically, residents are expected to rely more on non-photic cues (e.g. food, temperature, social cues) than migrants. We tested this general prediction using a social cue manipulation. First, we compared the effects of subspecies-appropriate recorded male song on reproductive development in migrants and residents on a naturally increasing photoperiod. Second, we tested the sensitivity of migrant-specific life history events (fattening and pre-alternate molt) to song treatment. After 82 days, residents had higher luteinizing hormone and greater ovarian development than migrants, but song treatment had no effect on these metrics in either subspecies. Song advanced pre-alternate molt but had no effect on fattening in migrants. While our study does not support specialization in social cue use in migrants and residents, it is consistent with findings in the literature of specialization in photoperiodic response. It also demonstrates for the first time that social cues can influence molt in a migrant species. Additional findings from a pilot study looking at responses to a live male suggest it is important to test other kinds of social cues.

Africa: Supervolcano Minerals Discovery to Boost Green Cars – Study

[Thomson Reuters Foundation] Toronto -Scientists have found an unexpected new source for lithium, a key component in battery-powered electric cars and other renewable energy technologies: supervolcanoes.

New Evidence for That Huge Dinosaur Family Tree Rewrite

Remember that paper that dropped a few months ago completely rewriting the dinosaur family tree? Well, the researchers are back, this time using one of the odder dinos out there as evidence for their explosive claim. Is it legit or just hype? Back in March, researchers argued for a total takedown of the long-established dinosaur family tree. Today, Matthew Baron and Paul Barrett, two of the three authors of that previous Nature paper, try to bolster their case with a new look at Chiles

SpaceX Sets August 14 Launch Date for Next US Resupply Mission to ISS

Kennedy Space Center FL (SPX) Aug 14, 2017
Three tons of supplies and payloads for the International Space Station are scheduled for a Monday afternoon launch at the Kennedy Space Center, SpaceX said in a press release on Wednesday. The Dragon spacecraft, launched atop the SpaceX Falcon 9 rocket, will deliver nearly 6,000 pounds of supplies and payloads, including materials to support more than 250 science and research experiments,

Building Wealth through Venture Capital: A Practical Guide for Investors and the Entrepreneurs They Fund


 
Venture capital demystified, for both investors and entrepreneurs

Building Wealth Through Venture Capital is a practical how-to guide for both sides of the table—investors and the entrepreneurs they fund. This expert author duo combines renowned venture capital experience along with the perspective of a traditional corporate executive and investor sold on this asset class more recently to flesh out wealth-building opportunities for both investors and



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