When going through stressful situations, some people lose their appetite. Similarly, animals that fear for their lives tend to eat less. In nature, this change in behavior could have downstream effects. Dumas Galvez, a postdoctoral researcher at the Smithsonian Tropical Research Institute (STRI), wondered how fear of predation might influence the eating habits of important seed dispersers such as the Central American agouti, a rodent that likes to nibble. the seeds of Attalea butyraceaa tropical palm also known as corozo, palma real or palma de vino.
Agouti are afraid of big cats and can detect their presence by smell. It helps that one of their main predators – ocelots – uses their urine and feces to mark their home area. Hungry agoutis may pick up this scent and avoid feeding in these sites. Galvez, alongside Marisol Hernandez, a biology student from the University of Panama, conducted various experiments in the Parque Natural Metropolitano and Gamboa of Panama to test this hypothesis.
By labeling and monitoring Attalea butyracea seeds and with the help of camera traps, digital cameras with sensors to detect passing animals, they first found that agoutis were less likely to disperse and steal seeds in sites perceived to have a high density of ocelots, especially during the rainy season when there is more food available. A second experiment with urine and feces from ocelots also found less dispersal by agoutis when these cues were present. Their findings were recently published in the journal Behavioral ecology.
Scientists are studying behavioral changes seen in agoutis associated with their perceived risk of predation, “the ecology of fear”. These effects are likely to occur between other feral cat species and seed-dispersing rodents. The reduced rates of seed dispersal and consumption associated with frightened rodents may, in turn, help maintain plant diversity in forest ecosystems.
“In the case of this species of palm, seeds that remain on the ground are also attacked by bruchid beetles, so lower seed dispersal rates by agoutis in ‘spooky areas’ allow the beetles to have more time to attack those seeds,” Galvez said. “Thus, ocelots may indirectly benefit other plants: the combined predation of seeds by agoutis and bruchids reduces the possibility that A.butyracea dominates in the forest, allowing other plant species to flourish.
Nevertheless, some questions remain to be resolved. For example, do agoutis go hungry for fear of predation or do they depend on other food sources in at-risk habitats? Further work could help solve this mystery.
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Material provided by Smithsonian Tropical Research Institute. Original written by Leila Nilipour. Note: Content may be edited for style and length.