Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Natural enemies help scientists untangle tropical forest food webs

18.03.2004


British ecologists have gathered compelling new experimental evidence on how tropical rain forest food webs are constructed, findings that may have important implications for their environmental management.



The research reported in Nature today (18 March) demonstrates how species that never meet may nevertheless influence each other’s ecology through shared parasites, and confirms the action of an important ecological theory in the highly biodiverse rain forest environment.

Ecologists have long believed that species which have nothing in common but a ’natural enemy’ - something that eats or parasitises both of them - may interact indirectly. The patterns that result parallel those caused by traditional competition for food, hence the name given to the effect: ’apparent competition’.


To test the theory scientists conducted a painstaking field experiment in Belize, Central America, measuring the effects of removing a beetle and a fly on other species with which they share natural enemies.

The beetle and fly belong to a very diverse group of insects whose larvae, named leaf miners, feed inside the leaves of plants. To take away just these particular insect leaf miners, researchers removed all traces of the plant that sustains only them.

A year after their removal, researchers surveyed the health of the insect species that shared natural enemies with the beetle and fly and found significantly lower parasitism and significantly higher abundance.

"This is basic ecological research intended chiefly to increase our understanding of these insect communities, but it also speaks to a number of biodiversity and management issues," said Professor Charles Godfray from the Natural Environment Research Council (NERC) Centre for Population Biology at Imperial, and author of the research.

If the results are typical of herbivore communities, say the authors, the development of this theory, and its associated experimental tests, will be essential to understand the diversity and structure of insect communities, especially in the species-rich tropics.

"It suggests that removal or addition of species, for example through selective logging or the release of a biological control agent, may have knock-on effects mediated by the network of natural enemies," said Professor Godfray.

The authors of the research from the NERC Centre for Population Biology at Imperial College London and the University of Oxford carried out the large-scale field experiment at the Natural History Museum’s Las Cuevas Research Station in Belize, Central America.

Their experiment wasn’t simple or easy: while scientists have carried out tests of apparent competition along coastal shorelines and in laboratory systems, manipulative experiments on insect communities in an environment as complex as a tropical forest are difficult and challenging and have rarely been attempted. Parasitism and predation can be especially intense, and levels of insect biodiversity are exceptionally high.

Previous work at the site by the same group led by one of the authors, Dr Owen Lewis, revealed the complexity of the food web they were studying: 93 species of leaf miner were attacked by 84 species of parasitoid wasp. Of the plants that were host to leaf miners, most were attacked by a single species but the researchers found that the vine plant Lepidaploa tortuosa was home to two leaf miners - a fly and a beetle (Latin names Pentispa fairmairei and Calycomyza sp. 8 respectively).

To test the apparent competition theory the researchers removed all of the L.tortuosa in their experimental fieldwork plots, alongside a 6-km stretch of track, in December 2001. In control plots the same biomass of plant material was removed from randomly chosen plant species that were not attacked by leaf miners.

Ten to 12 months, or five to six leaf miner generations, later, the scientists returned to measure the difference the clearance had made on the amount of parasitism and abundance of insects in the leaf miner food web.

Dr Becky Morris, a postdoctoral research associate at the NERC Centre for Population Biology and first author on the paper, masterminded the experimental work in Belize, organising and carrying out the host plant clearance.

The research was supported by the Natural Environment Research Council.

Tom Miller | alfa
Further information:
http://www.imperial.ac.uk
http://www.cpb.bio.imperial.ac.uk

More articles from Life Sciences:

nachricht BigH1 -- The key histone for male fertility
14.12.2017 | Institute for Research in Biomedicine (IRB Barcelona)

nachricht Guardians of the Gate
14.12.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Plasmonic biosensors enable development of new easy-to-use health tests

14.12.2017 | Health and Medicine

New type of smart windows use liquid to switch from clear to reflective

14.12.2017 | Physics and Astronomy

BigH1 -- The key histone for male fertility

14.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>