Navigation Links
Natural Selection in Butterflies

An international team of researchers has found natural selection in a tropical butterfly species that fought back - genetically speaking - against a highly invasive, male-killing bacteria.

Within 10 generations that spanned less than a year, the proportion of males of the Hypolimnas bolina butterfly on the South Pacific island of Savaii jumped from a meager 1 percent of the population to about 39 percent.

The researchers considered this a stunning comeback and credited it to the rise of a suppressor gene that holds in check the Wolbachia bacteria, which is passed down from the mother and selectively kills males before they have a chance to hatch.

"To my knowledge, this is the fastest evolutionary change that has ever been observed," said Sylvain Charlat, lead author of the study and a post-doctoral researcher with joint appointments at the University of California, Berkeley, and University College London.

"This study shows that when a population experiences very intense selective pressures, such as an extremely skewed sex ratio, evolution can happen very fast."

Charlat pointed out that, unlike mutations that govern such traits as wing color or antennae length, a genetic change that affects the sex ratio of a population has a very wide impact on the biology of the species.

It is not yet clear whether the suppressor gene emerged from a chance mutation from within the local population, or if it was introduced by migratory Southeast Asian butterflies in which the mutation had already been established.

"We'll likely know more in three years' time when the exact location of the suppressor gene is identified," said Charlat. "But regardless of which of the two sources of the suppressor gene is correct, natural selection is the next step.

The suppressor gene allows infected females to produce males, these males will mate with many, many females, and the suppressor gen e will therefore be in more and more individuals over generations."

Charlat worked with Gregory Hurst, a reader in evolutionary genetics at University College London and senior author of the paper. Descriptions of all-female broods of H. bolina date back to the 1920s, but it wasn't until 2002 that Hurst and colleagues first identified Wolbachia bacteria as the culprit behind the distorted sex ratio.

"We usually think of natural selection as acting slowly, over hundreds or thousands of years," said Hurst. "But the example in this study happened in a blink of the eye, in terms of evolutionary time, and is a remarkable thing to get to observe."

The researchers noted that bacteria that selectively kill male offspring are found among a range of arthropods, so what was seen in this study may not be unusual, despite the fact that it has never before been described in the scientific literature. Previous research has revealed some of the extraordinary ways in which insects adapt to the pressures inherent when nearly all its members are of one gender.

Notably, Charlat and Hurst reported in an earlier study that, thanks to Wolbachia, when males of H. bolina, commonly known as the Blue Moon or Great Eggfly butterfly, become a rare commodity, the number of mating sessions for both males and females jumps, possibly as an attempt to sustain the population despite the odds.

Charlat added that the relationship between Wolbachia and the Blue Moon butterfly illustrates the so-called Red Queen Principle, an evolutionary term named after a scene in Lewis Carroll's famous book, "Through the Looking-Glass," in which the characters Alice and the Red Queen run faster and faster at the top of a hill, only to find that they remain in the same place.

"In essence, organisms must evolve or change to stay in the same place, whether it's a predator-prey relationship, or a parasite-host interaction," said Charlat. "In the case of H. bolina, we're witnessing an evolutionary arms race between the parasite and the host. This strengthens the view that parasites can be major drivers in evolution."

The researchers focused on the Samoan islands of Upolu and Savaii, where in 2001, males of the Blue Moon butterfly made up only 1 percent of the population. In 2006, the researchers embarked on a new survey of the butterfly after an increase in reports of male-sightings at Upolu.

They found that males that year made up about 41 percent of the Blue Moon butterfly population in Upolu. They hatched eggs from 14 females in the lab and confirmed that the male offspring from this group were surviving with sex ratios near parity.

For Savaii, the population was initially 99 percent female at the beginning of 2006. By the end of the year, researchers found that males made up 39 percent of the 54 butterflies collected.

The researchers focused on the Samoan islands of Upolu and Savaii, where in 2001, males of the Blue Moon butterfly made up only 1 percent of the population. In 2006, the researchers embarked on a new survey of the butterfly after an increase in reports of male-sightings at Upolu.

They found that males that year made up about 41 percent of the Blue Moon butterfly population in Upolu. They hatched eggs from 14 females in the lab and confirmed that the male offspring from this group were surviving with sex ratios near parity.

For Savaii, the population was initially 99 percent female at the beginning of 2006. By the end of the year, researchers found that males made up 39 percent of the 54 butterflies collected.




'"/>




Related medicine news :

1. Accuracy of Some Natural Family Planning Methods Questioned .
2. Natural formula for protection against vision loss
3. Naturally Occurring Hormone Can Lead To Miscarriage
4. Treating Leukemia With Natural Cells
5. Natural Sulfur Can Treat Pain From Osteoarthritis
6. Chronic Post-Traumatic Stress Disorder (PTSD) Risk In Young Natural Disaster Survivors
7. Tsunami Unplugged: Natural Disasters Favor the Under-privileged
8. ‘Natural Spring’ Starts A Week Ahead Now Than Before: UNH Scientit
9. An After-Dinner Nap Is A Natural Thing, Scientists Proved
10. The Most Natural Thing in the World
11. Natural Approach to Immune Regulation May Help Transplant Patients
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/27/2017)... ... , ... The Case Management Society of America (CMSA) will install six new ... membership has elected their upcoming President-Elect, Secretary, Treasurer and two Directors to serve on ... Advisory position has also been added to the BOD, per an appointment made by ...
(Date:3/27/2017)... ... March 27, 2017 , ... EpiGentek ... to pursue the recent RNA methylation “gold rush” with their established portfolio of ... newfound characteristics of N6-methyladenosine, or m6A , RNA methylation has received a ...
(Date:3/27/2017)... Foothill Ranch, California (PRWEB) , ... March 27, 2017 , ... ... company’s commitment to its customers. First National Capital has added 10 new sales professionals ... to grow its sales positions by 15 additional new hires over the course of ...
(Date:3/27/2017)... RICHEY, Fla. (PRWEB) , ... March 27, 2017 ... ... drug overdose deaths soared 167%,(1) with opioids alone responsible for over 33,000 of ... Kevin McCarty has sponsored Assembly Bill (AB) 1512, which proposes a tax on ...
(Date:3/25/2017)... ... March 25, 2017 , ... Norland at Swissray is pleased to announce the ... subjects. The ELITE DXA has an active scan window, which is more than double ... fit in the scan area could not undergo an accurate total body bone density or ...
Breaking Medicine News(10 mins):
(Date:3/27/2017)... -- A new survey from the American Association ... Program (CBP) significantly reduced beneficiary choice and access to ... forces beneficiaries to switch to unfamiliar or unsuitable testing ... AADE,s survey is the latest in a continuous ... the inherent problems with the CBP. Last year, a ...
(Date:3/27/2017)... YORK , March 27, 2017 FinancialBuzz.com ... Based ... adult use in states where cannabis is legal will generate $655 ... million will be from cannabis specific taxes, such as ... $96 million will be earned from state sales taxes that are ...
(Date:3/27/2017)... BioLineRx Ltd. (NASDAQ/TASE: BLRX), a clinical-stage ... AGI-134, an immunotherapy for the treatment of multiple cancers, obtained ... featured at the upcoming American Association for Cancer Research ... to be held on April 1-5, 2017. ... An abstract titled ...
Breaking Medicine Technology: