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Researchers document rice plants trapping & killing fall armyworm caterpillars
https://www.eurekalert.org/news-releases/1128171
INTRO: Rice plants and Venus flytraps share something in common that was not scientifically documented until recently. Using a faint smell to lure caterpillars into a trap, rice plants kill early-stage fall armyworm larvae by trapping them in a spikelet, the part at the end of a rice panicle where individual grains develop.
In its flowering stage, the spikelet opens to expose a floret for pollination. Covered in spike-like hairs called trichomes, the spikelet slowly closes on the caterpillar stuck on the barbs. Like many great moments of scientific discovery, the observation that led to the finding was unexpected for Devi Balakrishnan.
“This was not in the plan,” said Balakrishnan, Ph.D., in the department of entomology and plant pathology for the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas Division of Agriculture. “I was doing another experiment on rice with fall armyworms and started noticing these caterpillars were inside the spikelet, and they were dead.”
Death by rice spikelet. To figure out why and how many fall armyworms were getting trapped by rice spikelets, Balakrishnan conducted four different replication trials under the advisement of Rupesh Kariyat, an associate professor of crop entomology in the department who holds the Clyde H. Sites Endowed Professorship in International Crop Physiology for the Division of Agriculture and the Dale Bumpers College of Agricultural, Food and Life Sciences at the University of Arkansas.
They published their results in the journal Ecological Processes in March under the title “Rice spikelets trap and kill caterpillars using trichomes.”
The four complementary experiments showed that roughly 50 percent of the fall armyworm caterpillars, which were about a week old, were trapped and died in rice spikelets while attempting to feed on florets. The results were the same when the researchers placed rice leaves in the enclosure. About half of them died within 48 hours when trying to feed on the floret inside the spikelet.
A third experiment tested whether floral volatiles could guide fall armyworm caterpillars to the panicle. They found that the caterpillars showed a slight preference for panicles with floret-bearing spikelets rather than those at the dough stage, a later phase when the spikelet has closed to allow further development of the rice grain.
The findings provide preliminary evidence that spikelet trichomes may function as a defense mechanism against herbivores feeding on reproductive structures, the study states. “This is a proof of concept,” Kariyat said. “One of the things we still want to ask is if it is a combination of the smell of flowers, the trichomes and individual components in the flower and the species of rice.” (MORE - no ads)
https://www.eurekalert.org/news-releases/1128171
INTRO: Rice plants and Venus flytraps share something in common that was not scientifically documented until recently. Using a faint smell to lure caterpillars into a trap, rice plants kill early-stage fall armyworm larvae by trapping them in a spikelet, the part at the end of a rice panicle where individual grains develop.
In its flowering stage, the spikelet opens to expose a floret for pollination. Covered in spike-like hairs called trichomes, the spikelet slowly closes on the caterpillar stuck on the barbs. Like many great moments of scientific discovery, the observation that led to the finding was unexpected for Devi Balakrishnan.
“This was not in the plan,” said Balakrishnan, Ph.D., in the department of entomology and plant pathology for the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas Division of Agriculture. “I was doing another experiment on rice with fall armyworms and started noticing these caterpillars were inside the spikelet, and they were dead.”
Death by rice spikelet. To figure out why and how many fall armyworms were getting trapped by rice spikelets, Balakrishnan conducted four different replication trials under the advisement of Rupesh Kariyat, an associate professor of crop entomology in the department who holds the Clyde H. Sites Endowed Professorship in International Crop Physiology for the Division of Agriculture and the Dale Bumpers College of Agricultural, Food and Life Sciences at the University of Arkansas.
They published their results in the journal Ecological Processes in March under the title “Rice spikelets trap and kill caterpillars using trichomes.”
The four complementary experiments showed that roughly 50 percent of the fall armyworm caterpillars, which were about a week old, were trapped and died in rice spikelets while attempting to feed on florets. The results were the same when the researchers placed rice leaves in the enclosure. About half of them died within 48 hours when trying to feed on the floret inside the spikelet.
A third experiment tested whether floral volatiles could guide fall armyworm caterpillars to the panicle. They found that the caterpillars showed a slight preference for panicles with floret-bearing spikelets rather than those at the dough stage, a later phase when the spikelet has closed to allow further development of the rice grain.
The findings provide preliminary evidence that spikelet trichomes may function as a defense mechanism against herbivores feeding on reproductive structures, the study states. “This is a proof of concept,” Kariyat said. “One of the things we still want to ask is if it is a combination of the smell of flowers, the trichomes and individual components in the flower and the species of rice.” (MORE - no ads)