Navigation Links
Seagulls: Are males the weaker sex?

Male seagulls may be more vulnerable to their environment during embryonic development than females, according to Maria Bogdanova and Ruedi Nager from the University of Glasgow in the UK. Until now, the sex differences in developmental rate and susceptibility to unfavorable conditions during the embryonic stage in birds have received little attention. The paper (1) has just been published in Springers journal, Behavioral Ecology and Sociobiology.

In many birds, siblings hatch at different times, resulting in age hierarchies within broods, with younger chicks often suffering reduced competitive ability and poorer survival compared to older siblings. During the last phase of incubation, birds auditory system is developed and embryos communicate with each other by auditory stimuli. These vocalizations may act as a cue for later-developing embryos about forthcoming competition, and there is evidence that they can respond to these cues by accelerating their hatching time, to reduce their age disadvantage. However, it is unclear whether this flexibility in developmental rates is sex-specific.

Bogdanova and Nager experimentally manipulated the social environment of herring gull embryos and tested whether sibling contact during the embryonic stage affects the developmental rate of males and females differently, and whether this has consequences for their post-hatching performance. The last-laid eggs female gulls commonly lay three eggs - were incubated either alone with no information about the presence of older siblings (experimental group), or in contact with other eggs which provided information about the presence of more advanced embryos (control group, replicating natural conditions). Post-hatching, the chicks were reared either with nest mates or alone.

The researchers found a sex-specific effect of social environment on hatching duration and fledging* condition. When incubated in isolation, males hatched faster than females but both sexes fledged in similar, relatively good, condition. In contrast, when incubated with normal between-embryo contact, males were unable to hatch as fast and fledged in significantly poorer condition than females, regardless of whether they were reared singly or in a brood.

The authors conclude that their findings confirm that there are differences in the way male and female herring gull chicks respond to the challenges of hatching at different times. It would appear that females have the upper hand.


Contact: Joan Robinson

Related biology news :

1. Variety is the spice of life: too many males, too little time...
2. Gene in male fish lures females into sex
3. Simple reason helps males evolve more quickly
4. Vaginal reconstruction not needed for most inter-sex females, Hopkins study shows
5. Why do males and females frequently differ in body size and structure?
6. Influenza vaccine causes weaker immune response for children of rural Gabon than in semi-urban areas
Post Your Comments:
(Date:11/18/2015)... --> --> ... report titled  Gesture Recognition Market - Global Industry Analysis, ... to the report, the global gesture recognition market was valued at ... US$29.1 bn by 2021, at a CAGR of 20.3% ... dominated the global gesture recognition market in ...
(Date:11/17/2015)...  Vigilant Solutions announces today that Mr. Dick ... --> --> Mr. ... partnership at TPG Capital, one of the largest global ... in revenue.  He founded and led TPG,s Operating Group, ... from 1997 to 2013.  In his first role, he ...
(Date:11/12/2015)... Nov. 12, 2015  A golden retriever that stayed ... dystrophy (DMD) has provided a new lead for treating ... the Broad Institute of MIT and Harvard and the ... . Cell, pinpoints a protective ... the disease,s effects. The Boston Children,s lab of ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... November 25, 2015 The ... is a professional and in-depth study on the ...      (Logo: ) , ... industry including definitions, classifications, applications and industry chain ... the international markets including development trends, competitive landscape ...
(Date:11/24/2015)... SUNNYVALE, Calif. , Nov. 24, 2015 ... executives will be speaking at the following conference, and ... New York, NY      Tuesday, December 1, ... New York, NY      Tuesday, December 1, ...      Piper Jaffray Healthcare Conference, New York, NY ...
(Date:11/24/2015)... ... November 24, 2015 , ... International Society for ... of the premier annual events for pharmaceutical manufacturing: 2015 Annual Meeting. The conference ... ISPE hosted the largest number of attendees in more than a decade. ...
(Date:11/24/2015)... ... November 24, 2015 , ... This fall, global software solutions ... in five states to develop and pitch their BIG ideas to improve health and ... are competing for votes to win the title of SAP's Teen Innovator, an all-expenses ...
Breaking Biology Technology: