Navigation Links
The hungry caterpillar: Beware your enemy's enemy's enemy
Date:11/27/2012

When herbivores such as caterpillars feed, plants may "call for help" by emitting volatiles, which can indirectly help defend the plants. The volatiles recruit parasitoids that infect, consume and kill the herbivores, to the benefit of the plant. However, such induced plant odours can also be detected by other organisms. A new study published November 27 in the open access journal PLOS Biology shows how secondary parasitoids ('hyperparasitoids') can take advantage of these plant signals to identify parasitoid-infected caterpillars, and duly infect the primary parasitoid, to the detriment of the original plant.

Plant volatiles have long been considered to mediate this mutualistic relationship between plants and herbivores' natural enemies such as parasitoids. When a caterpillar feeds, the parasitoids are able to use the emitted volatiles to locate the otherwise inconspicuous caterpillar, releasing the plant from its attacker. This principle has made its way into sustainable agriculture by using natural enemies such as parasitoids to control herbivorous pests on agricultural crops. However, the largest group of enemies of parasitoids, hyperparasitoids, have so far been left out of studies in this area. This is because very little is known about the cues that hyperparasitoids use to locate their parasitoid hosts.

The new study, by a team of Dutch researchers led by Erik Poelman, shows that hyperparasitoids exploit the different plant odours that are released when a plant is fed upon by a parasitoid-infected caterpillar.

"In controlled laboratory assays as well as under field conditions, hyperparasitoids were offered plant odours coming from two types of plant: ones damaged by healthy caterpillars, and ones damaged by parasitoid-infected caterpillars. We found that they preferentially detected odours of plants damaged by infected caterpillars," explained Dr Poelman. "We were excited by these results as they indicate that hyperparasitoids rely on a network of interactions among plant, herbivore and parasitoids to locate their host".

To show how this complex network of interactions can reliably provide hyperparasitoids with information on the presence of their parasitoid host, the researchers collected saliva of the caterpillars, as they noticed the colour of saliva in healthy, non-host caterpillars was different to that of caterpillars hosting a parasitoid. Factors in caterpillar saliva play an important role in provoking the release of odours from plants, and a change in saliva composition may then alter the cocktail of odours emitted by the plant.

Indeed, Dr Poelman's team found that plant odours induced by the saliva of parasitized caterpillars was more attractive to hyperparasitoids than plant odours induced by the saliva of healthy caterpillars. Consequently, plant odours may actually reduce the benefit of attracting parasitoids to a plant.

"Our results demonstrate that the effects of herbivore-induced plant volatiles should be placed in a community-wide perspective that includes species at the fourth trophic level, to improve our understanding of the ecological functions of volatile release by plants," said Dr Poelman. In addition to the ecological aspects of their work, the authors also stress that their findings are important for developing Integrated Pest Management strategies, in which crops are manipulated to control insect pests by using parasitoids.

Although parasitoids are effective biological control agents, this study suggests that using plant odours to optimize biological control of pests may have side effects that could actually reduce the benefit of pest control, said Dr Poelman.


'/>"/>
Contact: Bryan Ghosh
bghosh@plos.org
44-122-344-2837
Public Library of Science
Source:Eurekalert

Related biology news :

1. Giant squids giant eyes: The better to see hungry whales with
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:1/3/2017)... VEGAS , Jan. 3, 2017 Onitor, ... the introduction of Onitor Track, an innovative biometric data-driven ... men, showcasing this month at the 2017 Consumer Electronics ... In the U.S., the World Health ... more than two-thirds of adults who are overweight or ...
(Date:12/20/2016)... 20, 2016   Valencell , the leading ... STMicroelectronics (NYSE: STM), a global semiconductor leader ... announced today the launch of a new, highly ... that includes ST,s compact SensorTile turnkey ... biometric sensor system. Together, SensorTile and Benchmark deliver ...
(Date:12/16/2016)... The global wearable medical device market, in terms of ... USD 5.31 billion in 2016, at a CAGR of 18.0% during ... ... in medical devices, launch of a growing number of smartphone-based healthcare ... healthcare providers, and increasing focus on physical fitness. ...
Breaking Biology News(10 mins):
(Date:1/20/2017)... , January 20, 2017 ... is one of leading causes of death worldwide. There ... the number of cancer related deaths increased gradually over ... in incidence rate of various cancers continues to drive ... research report by Global Market Insights, Inc. cancer biological ...
(Date:1/19/2017)... Research Future has a half cooked research report on Global Liquid ... and expected to reach USD 450 Million by the end of ... ... assessed as a swiftly growing market and expected that the market ... There has been a tremendous growth in the prevalence of cancer ...
(Date:1/19/2017)... and Markets ... addition of the "Implantable Biomaterials Market Analysis & ... to their offering. Report Highlights: ... current and future market trends to identify the investment opportunities ... numbers Key market trends across the business segments, Regions ...
(Date:1/19/2017)... GAITHERSBURG, Md. , Jan. 19, 2017 /PRNewswire/ ... a privately-held immunotherapeutics company targeting infectious diseases, announced ... the merger of PharmAthene and Altimmune in an ... Fund, HealthCap, Truffle Capital and Redmont Capital. The ... immunotherapeutics company with four clinical stage and one ...
Breaking Biology Technology: