Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Multi-species herbivore outbreak follows El Niño drought in Panama

18.10.2004


Plant-eating insects inhabit all forest ecosystems, but sometimes their numbers explode, resulting in massive tree defoliation. In the October issue of the Journal of Tropical Ecology researchers from the Smithsonian Tropical Research Institute (STRI) associate a severe moth outbreak with drought conditions following the 1997-1998 El Niño Southern Oscillation (ENSO) event in a dry lowland forest near Panama’s Pacific coast. If ENSO events become more common, repeated herbivore outbreaks might alter forest species composition.

"Although we regularly monitor insect populations from STRI’s Canopy Crane system, we were actually tipped off about the outbreak by the crane operator, who complained that his parked car was covered with insect droppings," explains STRI post-doctoral fellow, Sunshine Van Bael.

Moth larvae devoured 250% more leaf material than usual even as researchers were setting up an experimental protocol to monitor herbivores and leaf damage on twenty tree species reachable from the gondola on the arm of a 42 m tall modified construction crane in Panama City’s Metropolitan Park. The crane, one of two in Panama and nine worldwide, permits scientists to ascend into the treetops to study previously inaccessible aspects of forest dynamics and species diversity.



Dr. Annette Aiello, Staff Scientist at STRI noted smaller outbreaks at five other Pacific coast sites. Wondering if this was a country-wide phenomenon, entomologists at STRI’s research station on Barro Colorado Island and at the Sherman Canopy Crane near Panama’s Atlantic coast were advised to be on the lookout for increases in butterfly and moth larvae populations. However, lepidopteran numbers remained stable there. Whatever it was that caused the the Pacific Coast outbreak did not occur or have the same effect where rainfall levels were more constant.

"This outbreak was unusual because it involved a dozen insect species, and followed a drought associated with one of the most severe El Niño events experienced here. We don’t know how common outbreaks like this are in the tropics because people have begun to associate events like this with global climate change fairly recently," says Van Bael.

What caused the outbreak? Most likely the drought kept the caterpillars’ natural enemies out of play, but the exact cause will remain a mystery. The team monitored lepidopteran populations again, after a milder El Nino event in 2003, but saw no large-scale outbreaks.

Drought stress of host trees is thought to be a factor in temperate area outbreaks of spruce bud worm and gypsy moths. But such outbreaks often last for up to 10 years. This short-lived (5-6 week) event in Panama was brought under control quickly by hungry birds, parasitoid flies and wasps, and aggressive caterpillar diseases.

Climatologists predict that ENSO events will become more common as global temperatures rise. And because herbivores hit some tree species harder than others, repeated herbivore outbreaks could change the species composition of the forest. In a recent volume of the Journal of Tropical Ecology, ecologists in Borneo reported a similar outbreak in response to the ENSO event in 1998.

Van Bael cautions: "It’s becoming increasingly clear that we should pay attention to these harbingers of climate change. A better understanding of the deep natural history of these systems may help us to predict outbreaks involving crop pests or human disease vectors."

Beth King | EurekAlert!
Further information:
http://www.si.edu

More articles from Ecology, The Environment and Conservation:

nachricht Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.

nachricht 100 % Organic Farming in Bhutan – a Realistic Target?
15.06.2018 | Humboldt-Universität zu Berlin

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View

22.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>