Navigation Links
Why don't more animals change their sex?

New Haven, Conn. Most animals, like humans, have separate sexes they are born, live out their lives and reproduce as one sex or the other. However, some animals live as one sex in part of their lifetime and then switch to the other sex, a phenomenon called sequential hermaphroditism. What remains a puzzle, according to Yale scientists, is why the phenomenon is so rare, since their analysis shows the biological "costs" of changing sexes rarely outweigh the advantages.

A report by Yale scientists in the March issue of The American Naturalist says that while this process is evolutionarily favored, its rarity cannot be explained by an analysis of the biological costs vs benefits.

Sequential hermaphroditism naturally occurs in various organisms from plants to fishes. Following four decades of research that established why sex change is advantageous, the question remained why it is rare among animals. In this study, Yale graduate student Erem Kazancıoğlu and his advisor Suzanne Alonzo, assistant professor of ecology and evolutionary biology, demonstrate that sex change is surprisingly robust against costs.

While the adaptive advantage of sex change is well understood, it is not clear why relatively few animals change sex. According to Alonzo, "An intuitive, yet rarely studied, explanation is that the considerable time or energy it takes to change sex make hermaphroditism unfeasible for most animals."

To test whether the biological costs of changing sex affect sex change actually occurs, the researchers built theoretical models of the hermaphrodite and separate-sex life histories. In their "game" models, sex change "players" vary the age of their sex change, while the separate-sex strategy responds by altering the number of male and female offspring it produces.

"We were surprised to see that a hermaphrodite could spend 30 percent of its lifetime in the process of change sex, and still persist in a population," said Kazancıoğlu. "This suggests that only huge costs can disfavor sex change."

So, why is sex change so rare? And, why does one species of fish reproduce strictly as separate sexes, while another very closely related species flexibly changes sex? A comparative study of hermaphroditic and separate-sex mating systems, which the authors are currently performing, may provide a clue, according to Kazancıoğlu, "Reproductive behaviors such as parental care seem to disfavor sex change in some species. We are investigating whether general patterns like these may explain the rarity of hermaphroditism."


Contact: Janet Rettig Emanuel
Yale University

Related biology news :

1. Report: African, Asian, Latin American farm animals face extinction
2. UT researcher sheds new light on hybrid animals
3. Penn Veterinary Medicine report new strategy to create genetically-modified animals
4. UT researcher sheds new light on hybrid animals
5. Fungus genome yielding answers to protect grains, people and animals
6. From GM farm animals to embryonic stem cell research
7. Colorful view for first land animals
8. Gene guards grain-producing grasses so people and animals can eat
9. Texas A&M testing oral contraceptives for animals
10. Mantis shrimp vision reveals new way that animals can see
11. Common aquatic animals show extreme resistance to radiation
Post Your Comments:
Related Image:
Why don't more animals change their sex?
(Date:11/4/2015)... , November 4, 2015 ... new market report published by Transparency Market Research "Home Security ... Trends and Forecast 2015 - 2022", the global home security ... 30.3 bn by 2022. The market is estimated to ... period from 2015 to 2022. Rising security needs among ...
(Date:10/29/2015)... Va. , Oct. 29, 2015 Daon, ... today that it has released a new version of ... customers in North America have ... IdentityX v4.0 also includes a FIDO UAF certified ... are already preparing to activate FIDO features. These customers ...
(Date:10/29/2015)... 2015 Today, LifeBEAM , a ... 2XU, a global leader in technical performance sports ... with advanced bio-sensing technology. The hat will allow ... key biometrics to improve overall training performance. As ... will bring together the most advanced technology, extensive ...
Breaking Biology News(10 mins):
(Date:11/30/2015)... /PRNewswire/ - Zenith Epigenetics Corp. ("Zenith" or the "Company") today ... to its Board of Directors to replace Dr. ... wealth of experience as co-founder of Resverlogix, with expertise in ... --> --> Dr. Wong remarked, "I am ... Zenith,s long standing expertise in epigenetics and the advanced stage ...
(Date:11/30/2015)... Atlanta, GA (PRWEB) , ... November 30, 2015 ... ... announced a new globally touring exhibition Jurassic World: The Exhibition, opening in March ... Exhibition will embark on a worldwide tour including several North American tour dates. ...
(Date:11/30/2015)... 30, 2015 Human Longevity, Inc. (HLI), the ... acquired Cypher Genomics, Inc., a leading genome informatics company ... software solutions. The San Diego -based ... Cypher CEO and Co-founder, Ashley Van Zeeland , Ph.D., ...  Financial details of the deal were not disclosed. ...
(Date:11/30/2015)... SAN DIEGO , Nov. 30, 2015  HUYA ... China,s pharmaceutical innovations, today announced ... Korea Drug Development Fund (KDDF) to foster collaboration between ... Korean development and commercialization of healthcare products for the ... potential as an important source of new innovative preclinical ...
Breaking Biology Technology: