Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Male-killing bacteria makes female butterflies more promiscuous

06.02.2007
A study at UCL (University College London) finds that a high-prevalence of male-killing bacteria active in many species of insect including the butterfly, actually increases female promiscuity and male fatigue.

The team found that when the male insect population drops – killed off by the bacteria – the female butterfly becomes more sexually rampant. Males on the other hand show signs of fatigue and put less effort into mating.

In some populations of tropical butterfly the entire mating system is determined by a group of bacteria known as Wolbachia, according to the study, published in the journal ‘Current Biology’.

Dr Sylvain Charlat, of the UCL Department of Biology, who led the study, said: ”Male-killling bacteria are found in many insect species including the British ladybird. We wanted to know what the effect of the bacteria is on the mating system, and here we’ve shown that butterfly mating patterns are strongly determined by the killer bacteria.

... more about:
»Population »mating »promiscuity

“Contrary to expectation, we also find that female promiscuity actually rises when male numbers are reduced. Greater numbers of female partners leads to fatigue in males. They start producing smaller sperm packages. Unfortunately, the female butterflies instinctively know that the packages are smaller and that their chances of having been impregnated after mating are lower than usual. This just makes them more rampant!”

The male-killling bacterium is transmitted from mother to son and actually kills the son before the embryo hatches into a caterpillar. Only female offspring of female carriers of the bacteria can survive, which can lead to the male population being as low as one male to every hundred females in some areas.

Dr Greg Hurst, of the UCL Department of Biology and a senior author of the study, said: “It’s amazing that the numbers of male butterflies can get so low and yet the population is still sustainable and stable. You don’t need many male butterflies to continue the population successfully. This is partly because the decision to mate is mainly under female control and because males have a high mating capacity.”

This study was carried out on Hypolimnas bolina butterflies in Pacific Island and South-East Asian populations. The islands provide an ideal location because every island is differently affected by the male-killling bacteria so that each has a different ratio of males to females.

The researchers assessed the natural sex ratio in 20 populations and combined this data with female mating frequency and the size of the male sperm package (Spermatophore) per copulation to find how female promiscuity was affected by the sex ratio. They found that the size of the Spermatophore was key to female promiscuity. However, female promiscuity only rises up to the point where males become so rare that female virginity rates rise.

The male-killling phenomenon in this species was first identified in 1920 by Hubert Simmonds but has not received much attention until now. This finding is significant for the scientific community because it demonstrates how a species’ mating system can be determined by the frequency of a parasite.

Alex Brew | alfa
Further information:
http://www.ucl.ac.uk

Further reports about: Population mating promiscuity

More articles from Life Sciences:

nachricht Stiffness matters
22.02.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht Separate brain systems cooperate during learning, study finds
22.02.2018 | Brown University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Stiffness matters

22.02.2018 | Life Sciences

Magnetic field traces gas and dust swirling around supermassive black hole

22.02.2018 | Physics and Astronomy

First evidence of surprising ocean warming around Galápagos corals

22.02.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>