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Frontiers in Ecology and Evolution

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Aedes aegypti, non-lethal predation, larval competition, life-table, larval development time, body size, fecundity, population-level traits


Non-lethal, trait-mediated effects of predation impact prey behavior and life-history traits. Studying how these effects in turn influence prey demography is crucial to understand prey life-history evolution. Mosquitoes are important vectors that claim several million lives every year worldwide by transmitting a range of pathogens. Several ecological factors affect life-history traits of both larval and adult mosquitoes, creating effects that cascade to population-level consequences. Few studies have comprehensively explored the non-lethal effects of predation and its interactions with resources and competition on larval, adult, and population traits of mosquitoes. Understanding these interactions is important because the effects of predation are hypothesized to rescue prey populations from the effects of density-dependence resulting from larval competition. Aedes aegypti larvae reared at two different larval densities and subjected to three non-lethal predator treatments were monitored for survival, development time, and adult size through the larval stages to adult eclosion, and adult females were monitored for survival and reproduction through their first gonotrophic cycle. Intraspecific competition increased larval development time, yielded small-bodied adults, and reduced fecundity in individuals exposed to predatory chemical cues as larvae. Exposure to cues from a living predator affected both body size and latency to blood feed in females. Analysis of life-table traits revealed significant effects of competition on net reproductive rate (R0) of mosquitoes. The interaction between competition and predator treatments significantly affected the cohort rate of increase (r) and the index of performance (r’). The index of performance, which estimates rate of population change based on the size-fecundity relationship, was significantly and positively correlated with r, but overestimated r slightly. Lack of significant effect of predator treatments and larval density on cohort generation time (Tc) further suggests that the observed effects of treatments on r and r’ were largely a consequence of the effects on R0. Also, the significant effects of treatment combinations on larval development time, adult body size and fecundity were ultimately manifested as effects on life-table traits estimated from adult survival and reproduction.

Funding Source

This research was supported by: Fulbright-Nehru Doctoral Research Fellowship 2014-15 from the US-India Educational Foundation, New Delhi (India) and the Institute of International Education, New York (USA); 2015 Patel Grant sponsored by the Institute of International Education; R.D.Wiegel Phi Sigma Research Grant from the School of Biological Sciences, Illinois State University all to KC; and by National Institute of Health grants 1R15AI094322-01A1 and 1R15AI124005-01.


First published in Frontiers in Ecology and Evolution, volume 7 - 2019 |

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