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:5/20/2016)... MINNEAPOLIS , May 20, 2016  VoiceIt ... technology partnership with VoicePass. By working ... user experience.  Because VoiceIt and VoicePass take slightly ... two engines increases both security and usability. ... expressed excitement about this new partnership. ...
(Date:5/12/2016)... , May 12, 2016 , ... published the overview results from the Q1 wave of ... recent wave was consumers, receptivity to a program where ... with a health insurance company. "We were ... share," says Michael LaColla , CEO of Troubadour ...
(Date:5/3/2016)... Lithuania , May 3, 2016  Neurotechnology, ... released the MegaMatcher Automated Biometric Identification System ... of large-scale multi-biometric projects. MegaMatcher ABIS can process ... accuracy using any combination of fingerprint, face or ... MegaMatcher SDK and MegaMatcher Accelerator ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... MA (PRWEB) , ... June 23, 2016 , ... ... Peel Plate® YM (Yeast and Mold) microbial test has received AOAC Research Institute ... platform of microbial tests introduced last year,” stated Bob Salter, Vice President of ...
(Date:6/23/2016)... ... June 23, 2016 , ... STACS DNA Inc., the ... at the Arkansas State Crime Laboratory, has joined STACS DNA as a Field Application ... team,” said Jocelyn Tremblay, President and COO of STACS DNA. β€œIn further expanding our ...
(Date:6/23/2016)... , June 23, 2016 On ... session at 4,833.32, down 0.22%; the Dow Jones Industrial Average ... 500 closed at 2,085.45, down 0.17%. has initiated coverage ... INFI ), Nektar Therapeutics (NASDAQ: NKTR ), Aralez ... Inc. (NASDAQ: BIND ). Learn more about these ...
(Date:6/23/2016)... 23, 2016 adds ... to its pharmaceuticals section with historic and forecast ... much more. Complete report on the ... profiling 15 companies and supported with 261 tables ... . The Global Cell Culture ...
Breaking Biology Technology: