Navigation Links
High hormone levels in seabird chicks prepare them to kill their siblings
Date:6/18/2008

The Nazca booby, a Galpagos Island seabird, emerges from its shell ready to kill its brother or sister. Wake Forest University biologists and their colleagues have linked the murderous behavior to high levels of testosterone and other male hormones found in the hatchlings.

The study appears in the June 18 edition of the online journal PLoS ONE available at http://www.plosone.org/doi/pone.002460.

The elevated levels of male hormones, called androgens, increase aggression in both male and female chicks and prepare the birds to fight to the death as soon as they hatch, said David J. Anderson, professor of biology at Wake Forest and project leader.

Much of the field work was completed by Martina Mller, while she was a graduate student at Wake Forest.

"The older of two Nazca booby hatchlings unconditionally attacks and ejects the younger from the nest within days of hatching," Anderson said. Because Nazca boobies have difficulty raising more than one chick, it is important for the older chick to vanquish the younger one in order to increase its own chances of survival.

According to the study, the high hormone levels also cause the surviving chicks to behave like bullies after they grow up. They frequently seek out nestlings in their colony, and during those visits they often bite and push around the defenseless youngsters.

Blood samples were taken from Nazca booby chicks within 24 hours of hatching. In 15 nests with two eggs, blood samples were taken from both hatchlings. Samples were also taken from 15 hatchlings in one-egg nests. Then, blood hormones were analyzed by researchers at the University of Maryland, who co-authored the study. For comparison, the researchers did the same for blue-footed boobies, a closely related species.

The researchers suspect that the Nazca booby hatchlings experience the high level of aggression-related hormone during a "sensitive period" in their growth, when long-term growth patterns are easily affected.

Some Nazca booby nestlings experience a one-two hormonal punch, raising their aggression hormones even higher when they actually have a nest mate. The nestlings that fight siblings become bigger bullies as adults than the Nazca booby nestlings who never fight.

"The hormones that are part of this epic battle early in life seem to permanently change some aspects of their social personality," Anderson said.

Nazca booby chicks have aggression-related hormone levels three times as high as their less aggressive cousins, the blue-footed boobies. Blue-footed boobies do not have the same lethal fights right after hatching and do not go on to bully their fellow birds as adults.


'/>"/>

Contact: Cheryl V. Walker
walkercv@wfu.edu
336-758-5237
Wake Forest University
Source:Eurekalert  

Related biology news :

1. Circadian clock controls plant growth hormone
2. Study finds Viagra increases release of key reproductive hormone
3. Scientists uncover how hormones achieve their effects
4. Obesity-related hormone is higher in children with Down syndrome
5. Effects of social isolation traced to brain hormone
6. EMD Serono launches easypod, new electronic growth hormone injection device
7. Predicting growth hormone treatment success
8. Human hormone blocker found to help prevent obesity and diabetes: study
9. Research with squirrels provides clues on hormones role in human learning
10. MU researcher links hormone replacement therapy to breast cancer
11. NC State researchers identify genes key to hormone production in plants
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
High hormone levels in seabird chicks prepare them to kill their siblings
(Date:2/5/2016)... , Feb. 5, 2016 ... addition of the "Global Facial Recognition ... --> http://www.researchandmarkets.com/research/5kvw8m/global_facial ) has announced ... Recognition Market 2016-2020" report to their ... ( http://www.researchandmarkets.com/research/5kvw8m/global_facial ) has announced the addition ...
(Date:2/3/2016)... 3, 2016 Vigilant Solutions announces today that ... Missouri solved two recent hit-and-run ... data from Vigilant Solutions. Brian Wenberg ... the victim was walking out of a convenience store and witnessed an elderly ... his vehicle, striking his vehicle and leaving the scene.  ...
(Date:2/2/2016)... 2, 2016 Checkpoint Inhibitors for Cancer ... Are you interested in the future of ... checkpoint inhibitors. Visiongain,s report gives those predictions to ... national level. Avoid falling behind in data ... and revenues those emerging cancer therapies can achieve. ...
Breaking Biology News(10 mins):
(Date:2/4/2016)... Massachusetts , February 4, 2016 - New FDA ... - New FDA action date of July 22, ... of July 22, 2016   - ... U.S. in the past decade indicated for the treatment of signs and symptoms ... Lifitegrast has the potential to be the only product approved in the U.S. ...
(Date:2/4/2016)... China , Feb. 4, 2016 Beike ... and various medical institutions attended a ceremony in late ... integrative, personalized cell therapy in 2016. ... "Shenzhen Clinical Translation Platform for Personalized Cell Therapy" was ... Regional Cell Production Center, both subsidiaries of Beike Biotechnology ...
(Date:2/4/2016)... 2016 ContraVir Pharmaceuticals, Inc. (NASDAQ: CTRV ... commercialization of targeted antiviral therapies, announced today that it ... to be held February 8-9, 2016, at the Waldorf ... Growth & Healthcare Conference, taking place in ... James Sapirstein , Chief Executive Officer of ContraVir, ...
(Date:2/4/2016)... 4, 2016 Strasbourg, France ... --> Strasbourg, France , to the ... PharmaVentures is pleased to announce that it acted as an ... unit in Strasbourg, France , to the ... --> --> Transgene (Euronext: TNG), a member ...
Breaking Biology Technology: