Featured Research

from universities, journals, and other organizations

Genetics of life and death in an evolutionary arms-race

April 9, 2013
Manchester University
Scientists have found evidence of the genetic basis of the evolutionary arms-race between parasitoids and their aphid hosts.

Scientists at The University of Manchester have found evidence of the genetic basis of the evolutionary arms-race between parasitoids and their aphid hosts.

Related Articles

The researchers studied the reaction of aphids when a parasitic wasp with genetic variation laid eggs in them. They found that different genotypes of the wasp affected where the aphids went to die, including whether they left the plant host entirely. The team also found an example of the emergence of a shared phenotype that was partly wasp and partly aphid.

Dr Mouhammad Shadi Khudr, a visiting scientist at the Faculty of Life Sciences, led the research: “Natural selection on the aphid prey depends not only on aphid genes, but also on the genetics of the parasitic wasp. The indirect genetic effects underlying the relationship between natural enemies have been rarely shown, especially when they arise between species. Parasite-manipulation is endlessly fascinating, albeit with a somewhat ghoulish quality! This study sheds light on how genetic variation can influence that manipulation.”

The researchers began the study by breeding 13 males with 3 females of the wasp Aphidius ervi, through which a quantitative genetic design was created. The resulting offspring of full and half siblings provided a basis of genetic variation in the parasitic wasp to test how different individuals of the latter are associated with variation in the aphids’ behaviour when aphids are prone to the wasps’ manipulation. One genotype of the pea aphid Acyrthosiphon pisum was chosen. Since this species reproduces asexually by parthenogenesis, the resulting genetically identical individuals make up a specific type of colony known as ‘clone’.

The team then introduced the wasps into 156 cages that contained a broad bean plant and an aphid colony. They then compared the behaviour of aphids in the presence and absence of the wasp by monitoring what the aphids did over the next ten days. Successful parasitism ends with the death of the aphid host which becomes a pale brownish remainder called a ‘mummy’. Once the aphids had mummified, the location of each mummy was recorded according to its position on the plant and at other locations within the cage.

Dr Khudr says: “Our results confirm that parasitism by a parasitoid wasp can lead to behavioural modifications in an aphid host. The effect of the wasp fathers was significant on the distribution of the parasitised and non-parasitised aphids. There was also a notable effect of mothers indicating a maternal influence on the distribution of parasitised vs. non-parasitised aphids. This can reflect a fitness-difference between father families.”

As well as monitoring their behaviour whilst they were alive, the positions of the aphids’ bodies once the new wasp has hatched also varied both on and off the plants. This variation was dependent on the wasp genotype. It’s this relationship between the wasp and its host which starts with parasitism and ends with predation that fascinates Dr Khudr.

“What we’re witnessing on the broad bean plants is an evolutionary arms-race between two enemies where each one strives to cap each others’ fitness. This can be observed through varying manipulative strategies applied by the parasitic wasps in order to subdue their hosts. The wasp has to ensure the aphid can be kept alive long enough to ensure it can mature. The parasitised aphid will on occasion commit suicide if it realises it has the wasp growing within it and by doing so it can save the rest of the colony from a subsequent attack. What we’ve been able to do in this study is to open the window on how the genetics of one species influence the behaviour and manipulation of another host species.”

The findings have been published in the Royal Society’s Biology Letters. Discussing the findings Dr Khudr says he was surprised by what the team recorded: “We had expected some variation in the aphids’ movement and behaviour but not to the extent that we witnessed. An organism’s phenotype (behaviour) can be the product of the genes expressed in another organism”

The next step is to carry out further research to establish if specific genes in the wasps can be linked to particular behaviours in the aphids. Dr Khudr hopes this type of information could increase our understanding of the importance of genetic diversity in ecosystem services, and lead to the development of better biological controls for aphid populations.

Story Source:

The above story is based on materials provided by Manchester University. Note: Materials may be edited for content and length.

Journal Reference:

  1. Mouhammad Shadi Khudr et al. Parasitoid wasps influence where aphids die via an interspecific indirect genetic effect. Biology Letters, 2013 DOI: 10.1098/rsbl.2012.1151

Cite This Page:

Manchester University. "Genetics of life and death in an evolutionary arms-race." ScienceDaily. ScienceDaily, 9 April 2013. <www.sciencedaily.com/releases/2013/04/130409211904.htm>.
Manchester University. (2013, April 9). Genetics of life and death in an evolutionary arms-race. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2013/04/130409211904.htm
Manchester University. "Genetics of life and death in an evolutionary arms-race." ScienceDaily. www.sciencedaily.com/releases/2013/04/130409211904.htm (accessed December 19, 2014).

Share This

More From ScienceDaily

More Plants & Animals News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations

Featured Videos

from AP, Reuters, AFP, and other news services

Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Kids Die While Under Protective Services

Kids Die While Under Protective Services

AP (Dec. 18, 2014) As part of a six-month investigation of child maltreatment deaths, the AP found that hundreds of deaths from horrific abuse and neglect could have been prevented. AP's Haven Daley reports. (Dec. 18) Video provided by AP
Powered by NewsLook.com
Dads-To-Be Also Experience Hormone Changes During Pregnancy

Dads-To-Be Also Experience Hormone Changes During Pregnancy

Newsy (Dec. 18, 2014) A study from University of Michigan researchers found that expectant fathers see a decrease in testosterone as the baby's birth draws near. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.


Breaking News:

Strange & Offbeat Stories

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News


Free Subscriptions

Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile

Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?

Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins