Potential role of masting by introduced bamboos in deer mice (Peromyscus maniculatus) population irruptions holds public health consequences

Authors: Smith, Melissa; GOMULKIEWICZ, RICHARD - Washington State University; MACK, RICHARD - Washington State University

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/13/2015
Publication Date: 4/20/2015
Citation: Smith, M., Gomulkiewicz, R., Mack, R.N. 2015. Potential role of masting by introduced bamboos in deer mice (Peromyscus maniculatus) population irruptions holds public health consequences. PLoS One. 10(4):e124419. doi:10.1371/journal.pone.0124419.

Interpretive Summary: Masting species often trigger immediate responses in populations of seed foragers. The explosion of temperate Asian bamboos in U.S. horticulture, and incidence of their naturalizations, introduces another masting species into the forest flora. In the Pacific Northwest, and throughout North America, deer mice (Peromyscus maniculatus) play an important role as generalist consumers, but also are the sole vector for the Sin Nombre Virus, the cause of the deadly hantavirus pulmonary syndrome (HPS) in humans. Deer mice populations are intimately tied to fluctuations in primary productivity, including masting events. For instance, the explosion of HPS cases in the U.S. Southwest in the 1990’s is highly correlated to a masting event in Pinon pines that contributed to a population explosion in deer mice. To test the potential outcome of large-scale bamboo invasions, we conducted multiple-choice feeding trials and reproductive feeding trials with deer mice. Deer mice readily consumed bamboo seeds in equal amounts to other seed sources and reproduced the same number of pups on a diet of bamboo compared to a native diet with seeds and insects. Our results point to a growing need for epidemiologists and ecologists to investigate the linkages between plant invasions, and native pathogen reservoirs and vectors.

Technical Abstract: Plant invasions can bolster or even create new functional links among species that facilitate parasitism. For example, introductions of some running bamboos into North America could ultimately lead to disease outbreaks analogous to well documented examples involving native bamboos and rodents in Asia and South America. We hypothesize that naturalized Asian bamboos in North American coniferous forests could produce pulses in the population size of native granivorous deer mice (Peromyscus maniculatus), a Hantavirus carrier, which could in turn hold dire public health consequences. In feeding trials, deer mice consumed bamboo seeds (Bambusa distegia and Yushania brevipaniculata) as frequently as native seeds. Furthermore, deer mice fed a diet of bamboo seeds produced litter sizes equal to those from mice fed a native diet. But masting, i.e. simultaneous flowering and abundant seed production, in a forest community’s naturalized bamboo population could readily trigger an exponential rodent population increase. With abrupt cessation of bamboo seed availability, the incidence of deer mice-human transmission of the Hantavirus could increase as peridomestic deer mice disperse to seek food. The Hantavirus Pulmonary Syndrome infections at Yosemite National Park in summer 2012 forcefully draw attention to the persistent links between vectors of zoonotic diseases and public health. Keywords: emerging infectious diseases, masting bamboos, Peromyscus maniculatus, plant invasions, coniferous forests