Butterflies and moths are well known for their striking metamorphosis from crawling caterpillars to winged adults. In light of this radical change, not just in body form, but also in lifestyle, diet and dependence on particular sensory cues, it would seem unlikely that learned associations or memories formed at the larval or caterpillar stage could be accessible to the adult moth or butterfly. However, scientists at Georgetown University recently discovered that a moth can indeed remember what it learned as a caterpillar. Their findings are published in the March 5, 2008 edition of the journal PLoS ONE.
The Georgetown researchers found that tobacco hornworm caterpillars could be trained to avoid particular odors delivered in association with a mild shock. When adult moths emerged from the pupae of trained caterpillars, they also avoided the odors, showing that they retained their larval memory. The Georgetown University study is the first to demonstrate conclusively that associative memory can survive metamorphosis in Lepidoptera—the order of insects that includes moths and butterflies—and provokes new questions about the organization and persistence of the central nervous system during metamorphosis.
“The intriguing idea that a caterpillar’s experiences can persist in the adult butterfly or moth captures the imagination, as it challenges a broadly-held view of metamorphosis -- that the larva essentially turns to soup and its components are entirely rebuilt as a butterfly,” says senior author Martha Weiss, an associate professor of Biology at Georgetown University.
“Scientists have been interested in whether memory can survive metamorphosis for over a hundred years,” says first author Doug Blackiston, who completed the interdisciplinary research while earning a PhD in Biology from Georgetown University in the labs of developmental biologist Elena Casey and behavioral ecologist Martha Weiss. The brain and nervous system of caterpillars is dramatically reorganized during the pupal stage and it has not been clear whether memory could survive such drastic changes.
The findings of the Georgetown researchers suggest the retention of memory is dependent on the maturity of the developing caterpillars’ brains. Caterpillars younger than three weeks of age learned to avoid an odor, but could not recall the information as adults, whereas older caterpillars, conditioned in the final larval stage before pupation, learned to avoid the odor and recalled the information as adults. In addition, the results have both ecological and evolutionary implications, as retention of memory through metamorphosis could allow a female butterfly or other insect to lay her eggs on the type of host plant that she herself had fed on as a larva, a behavior that could shape habitat selection and eventually lead to development of a new species.
While most research on learning and memory in insects has centered on social insects, such as honeybees or ants, Weiss’ lab is particularly interested in solitary insects, such as butterflies, praying mantids, and mud-dauber wasps. Weiss and her colleagues will continue to study how these self-sufficient, multitasking insects use learning and memory skills to adapt to their environments.
This study was farther afield from the neural cell specification research that is ongoing in Casey’s lab. Casey, associate professor of Biology at Georgetown, focuses on identifying the signals that are required to direct a cell to develop into a neuron and determining how the complex human central nervous system evolved.
Blackiston, now conducting postdoctoral work at the Forsyth Center for Regenerative and Developmental Biology and the Department of Developmental Biology at the Harvard School of Dental Medicine, is currently examining learning and memory in aquatic vertebrates.About Georgetown University
Rebecca Walton | alfa
Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory
Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
09.12.2016 | Life Sciences
09.12.2016 | Ecology, The Environment and Conservation
09.12.2016 | Health and Medicine