Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Caterpillars mimic one another for survival

19.12.2011
A new study in the current issue of The Annals of the Entomological Society of America helps scientists better understand how organisms depend upon one another

In the world of insects, high risk of attack has led to the development of camouflage as a means for survival, especially in the larval stage. One caterpillar may look like a stick, while another disguises itself as bird droppings. Though crypsis may have its advantages, University of Florida researchers uncovered some of the most extensive evidence of caterpillars using another strategy previously best-known in adult butterflies: mimicry.

Insects use camouflage to protect themselves by looking like inanimate or inedible objects, while mimicry involves one species evolving similar warning color patterns to another.

The study in the current issue of The Annals of the Entomological Society of America helps scientists better understand how organisms depend upon one another, an important factor in predicting how disturbance of natural habitats may lead to species extinctions and loss of biodiversity.

"Mimicry in general is one of the best and earliest-studied examples of natural selection, and it can help us learn where evolutionary adaptations come from," said UF lepidopterist Keith Willmott, lead author of the study and an associate curator at the Florida Museum of Natural History on the UF campus.

Bright warning coloration has evolved in many insects with physical or chemical defenses and further research into how insects metabolize plant toxins for their own benefit has potential use in the medical field.

"It's very interesting how caterpillars can detoxify a plant's poisonous chemicals and resynthesize them for their own chemical defense or for pheromones," said Florida Museum collection coordinator and study co-author Andrei Sourakov. "We can look at the caterpillars' metabolic systems to understand how they deal with secondary plant compounds, the toxic plant substances used for centuries as tonics, spices, medicine and recreational drugs."

Based on the number of eggs laid by a single female butterfly, scientists estimate about 99 percent of caterpillars die before reaching the pupal stage. Survival tactics include sharp spines, toxic chemicals and hairs accompanied by bright warning coloration.

The study focuses on two groups of Neotropical caterpillars: Danaini of the Caribbean Island of Hispaniola and Ithomiini of the upper Amazon in eastern Ecuador. Sourakov raised and observed danaine caterpillars, including the monarch butterfly and its relatives. These species apparently form Müllerian mimicry rings, in which toxic species adopt the same warning color patterns so a predator will more quickly learn which species to avoid.

In Ecuador, Willmott and study co-author Marianne Elias, from the Muséum National d'Histoire Naturelle in Paris, found that 22 of 41 ithomiine caterpillars displayed some kind of warning coloration. Five exhibited a previously undocumented pattern with a bright yellow body and blue tips, and four were likely Batesian mimics, in which edible species adopt the coloration of an unpalatable model species for protection. These "freeloaders" only appear to have the defense mechanisms of the model species.

"They act almost like parasites, because the mimics are actually edible and therefore deceive predators without having to invest in costly resources to maintain toxicity," Willmott said. "Such a system can only be stable when the mimics are relatively rare, otherwise predators will learn the trick and attack more individuals of both mimics and models, driving models to evolve novel color patterns to escape the predators."

Mimicry may be relatively rare in caterpillars because it is more difficult for them to establish bright coloration, Willmott said. A brightly colored caterpillar has less chance of evading predators than a mobile adult butterfly.

"In adults, bright coloration may be favored by sexual selection for signaling to males and females," Willmott said. "Bright colors may be disadvantageous since they attract predators, but advantageous for attracting mates. Once established, bright colors might then be modified by natural selection for mimicry, another possible reason why mimicry seems to evolve much more frequently in adults than in caterpillars."

However, Sourakov believes mimicry is more common in caterpillars than scientists realize, but may receive less attention because larvae must be raised to adulthood to identify mimicry complexes, a process that takes weeks of lab work. Also, few collections of immature stages are maintained, and colors are not as well preserved in caterpillars.

"We know mimicry is an important ecological process for several species of animals, and I hope this study will give people incentive to further research immature stages of insects," said Andre Victor Lucci Freitas, a professor in the Instituto de Biologia at Universidade Estadual de Campinas. "We need to remember in most insects, immature stages are the most abundant."

Richard Levine | EurekAlert!
Further information:
http://www.entsoc.org

More articles from Life Sciences:

nachricht Scientists unlock ability to generate new sensory hair cells
22.02.2017 | Brigham and Women's Hospital

nachricht New insights into the information processing of motor neurons
22.02.2017 | Max Planck Florida Institute for Neuroscience

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Microhotplates for a smart gas sensor

22.02.2017 | Power and Electrical Engineering

Scientists unlock ability to generate new sensory hair cells

22.02.2017 | Life Sciences

Prediction: More gas-giants will be found orbiting Sun-like stars

22.02.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>