The Galapagos Islands, made famous by Charles Darwin, have a unique biota now highly threatened by invasive species because of increased tourism and population growth. Indeed, alien or exotic insects today constitute 23 percent of the Galapagos insect fauna. One of these insect invaders is the cottony cushion scale, a sap sucking bug native to Australia.
Capable of infesting many woody ornamentals and crops, the cottony cushion scale decreases the vitality of its host by sucking phloem sap from the leaves, twigs, branches, and trunk. But natural enemies, such as the lady bug beetle, Rodolia cardinalis, can bring the cottony cushion scale under control in a short time – a form of pest suppression called biocontrol.
In fall 2009, entomologist Mark Hoddle, the director of the Center for Invasive Species at the University of California, Riverside, and colleagues visited the Galapagos Islands to assess the impact and safety of the lady bug beetle that had been released in 2002 to suppress the cottony cushion scale.
"Populations of cottony cushion scale in 2002 were so high and spread across so many islands that several endemic and native plant populations were thought to be going into decline because of heavy infestations," said Hoddle, also a biocontrol specialist in the Department of Entomology.
Combating the cottony cushion scale was a joint effort between the Charles Darwin Research Foundation and the Galapagos Islands National Park Service, which neighbors the foundation on the island of Santa Cruz in the Galapagos.
"Soon after release, the lady bug beetle readily established and spread," Hoddle said. "Subsequent monitoring indicated that it was having the desired effect on the cottony cushion scale populations, which were collapsing because of feeding by larval and adult lady bug beetles. Our project was to follow up to see whether the lady bug beetle in 2009 was still exerting high levels of control over the cottony cushion scale and whether the project was safe as predicted by lab studies."
After about three months of survey work Hoddle, along with Christina Hoddle (UCR), Charlotte Causton (Charles Darwin Research Station), and Roy Van Driesche (University of Massachusetts, Amherst), concluded that the cottony cushion scale populations were very low in most areas on the Galapagos Islands.
"Pest numbers have been reduced by more than 99 percent on some native plants like mangroves, which were very susceptible to attack by cottony cushion scale," Hoddle said. "While from other rarer native plants, like Darwiniothamnus tenuifolius, the pest appears to have been completely removed."
To assess the impact of the beetle on the cottony cushion scale, Hoddle's team surveyed native plants across five different islands – Santa Cruz, Isabela, Espanola, San Cristobal, and Santiago – and recorded the presence and absence of cottony cushion scale and the lady bug beetle, and their densities. The team then compared the data to similar data from the same areas – and in many instances, from the very same trees – that had been collected before the lady bug beetle was released into the Galapagos.
"We also found no evidence that the lady bug beetle was attacking non-target species," Hoddle said. "The bug was never seen feeding on other insects in the Galapagos even when the cottony cushion scale and the non-target species were side by side on the same twig."
The cottony cushion scale project with the beetle was born in Southern California in 1888-1889 and saved California's then fledging citrus industry.
"The project in the Galapagos is an extension of the California success story," Hoddle said. "But in the Galapagos the biocontrol agent is protecting native plants instead of agricultural crops. The project has gone full circle – from 1880's citrus protection in Southern California to, in 2010, conservation of endangered plants in the Galapagos. A pretty incredible progression that would have been inconceivable by California entomologists and citrus workers back in 1888!"
The University of California, Riverside (www.ucr.edu) is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment of about 18,000 is expected to grow to 21,000 students by 2020. The campus is planning a medical school and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Graduate Center. The campus has an annual statewide economic impact of more than $1 billion.
A broadcast studio with fiber cable to the AT&T Hollywood hub is available for live or taped interviews. To learn more, call (951) UCR-NEWS.
Iqbal Pittalwala | EurekAlert!
Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF
Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
17.07.2018 | Information Technology
17.07.2018 | Materials Sciences
17.07.2018 | Power and Electrical Engineering