Seasonal Differences in Density But Similar Competitive Impact of Aedes albopictus (Skuse) on Aedes aegypti (L.) in Rio de Janeiro, Brazil

Extrinsic mortality impinging on negative density‐dependent populations can result in no change in the number of survivors (compensation) or an increase (overcompensation) by releasing the population from density‐dependent effects on survivorship. The relationship between the level of extrinsic mortality (i.e., percentage of mortality) and the level and likelihood of overcompensation is theoretically important, but rarely investigated. We tested the hypothesis that overcompensation occurs below a threshold value of extrinsic mortality that is related to density‐dependent mortality rate and that additive extrinsic mortality occurs above this threshold. This hypothesis predicts that survivorship vs. extrinsic mortality will (1) be best described by a two‐segmented model with a threshold; (2) have a slope >0 below the threshold; and (3) have a slope = −1 above the threshold. We also tested whether mortality imposed by real predators and random harvest have equivalent effects on adult production and whether magnitude of overcompensation is related to species sensitivity to density dependence. These hypotheses were tested in the container mosquitoes Aedes aegypti, Aedes albopictus, Aedes triseriatus, and Culex pipiens (Diptera: Culicidae). Cohorts of 150 larvae were exposed to random harvest of 0–70% two days after hatch or to predation by 1–3 Mesocyclops longisetus (Crustacea: Copepoda). Overcompensation occurred in A. aegypti in a pattern consistent with predictions. Aedes triseriatus showed strong overcompensation but no evidence of a threshold, whereas A. albopictus and C. pipiens had survival consistent with compensatory mortality but no evidence of a threshold. Compared to random harvest, mortality from predation yielded greater adult production in A. aegypti and A. albopictus, lesser adult production in C. pipiens, and no difference in adult production in A. triseriatus. Our results are largely consistent with our hypothesis about overcompensation, with the caveat that thresholds for additive mortality appear to occur at very high levels of extrinsic mortality. Magnitudes of overcompensation for the three Aedes were inversely related to survival in the 0% mortality treatment, consistent with our hypothesis that overcompensation is related to sensitivity to density dependence. A broad range of extrinsic mortality levels can yield overcompensation, which may have practical implications for attempts to control pest populations.

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“…, Johnson and Sukhdeo , Camara et al. ). Containers were returned to the environmental chamber, which maintained a 14:10 light:dark photoperiod.…”

Section: Methodsmentioning

confidence: 99%

Finding the sweet spot: What levels of larval mortality lead to compensation or overcompensation in adult production?

Neale

Juliano

2019

Ecosphere

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“…Hence, the Latin America outbreak was explained by 2015'El Niño-Oscillation South' 2015-2015 at continental level, but also at sub-regional level in Brazil it was explained by year to year variability (drought 2013-2015) and decadal variability followed by long-term trends as climate change (warm 2014-2015) (Munoz et al, 2016;Caminade et al, 2017). Furthermore, biological topics, as vector competence of local vectors (Gardner et al, 2016), vector competence between species (Camara et al, 2016), and the timing and location of vector or virus introduction (Robert et al, 2016;Walther et al, 2017) can change the probability and magnitude of transmission. Nevertheless, the anthropogenic factors usually are the main ones that trigger actual epidemics, even through climatic extreme events (Ahmed and Memish, 2017), and so some modeling in border areas includes also travel between borders and socioeconomic factors (Monaghan et al, 2016), while drivers of non-vectorial transmission still need better epidemiological elucidation (Guzzetta et al, 2016).…”

Section: Modes Of Transmission Vectorial Transmissionmentioning

confidence: 99%

Zika Virus: What Have We Learnt Since the Start of the Recent Epidemic?

2018

Frontiers Research Topics

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Zika is a viral disease transmitted mainly by mosquitoes of the genus Aedes. In recent years, it has expanded geographically, changing from an endemic mosquito-borne disease across equatorial Asia and Africa, to an epidemic disease causing large outbreaks in several areas of the world. With the recent Zika virus (ZIKV) outbreaks in the Americas, the disease has become a focus of attention of public health agencies and of the international research community, especially due to an association with neurological disorders in adults and to the severe neurological and ophthalmological abnormalities found in fetuses and newborns of mothers exposed to ZIKV during pregnancy. A large number of studies have been published in the last 3 years, revealing the structure of the virus, how it is transmitted and how it affects human cells. Many different animal models have been developed, which recapitulate several features of ZIKV disease and its neurological consequences. Moreover, several vaccine candidates are now in active preclinical development, and three of them have already entered phase I clinical trials. Likewise, many different compounds targeting viral and cellular components are being tested in in vitro and in experimental animal models. This review aims to discuss the current state of this rapidly growing literature from a multidisciplinary perspective, as well as to present an overview of the public health response to Zika and of the perspectives for the prevention and treatment of this disease.

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“…Inter‐ and intraspecific competition for resources is often important in container habitats, with field and laboratory studies demonstrating frequent negative effects of density on mosquito larvae (Juliano, ; Walsh et al., , ; Camara et al., ).The outcomes of these experiments are variable, with different detritus types (e.g. leaf species, plant versus animal) and ratios altering the outcome of density‐dependent competition (Yee et al., ; Murrell & Juliano, ; Juliano, ).…”

Section: Introductionmentioning

confidence: 99%

The roles of history: age and prior exploitation in aquatic container habitats have immediate and carry‐over effects on mosquito life history

Westby

Juliano

2017

Ecological Entomology

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Per-capita resource availability in aquatic habitats is influenced directly by consumer density via resource competition and indirectly via delayed resource competition when temporally non-overlapping cohorts of larvae exploit the same resources. In detritus-based systems, resources are likely to be influenced by the age of the aquatic habitat, as detritus changes in quality over time and may be replenished by new inputs.For aquatic insects that exploit detritus-based habitats, feeding conditions experienced during immature stages can influence fitness directly via effects on development and survivorship, but also indirectly by influencing adult traits such as fecundity and longevity.Larval habitat age and prior resource exploitation were manipulated in a field experiment using the container mosquito Aedes triseriatus.It was found that A. triseriatus from older habitats had greater larval survival, faster development and greater adult longevity. Exploitation of larval habitats by a prior cohort of larvae had a significant negative effect on subsequent cohorts of larvae by delaying development.It is suggested that extended conditioning of detritus probably resulted in conversion of recalcitrant resources to more available forms which improved the quality of the habitat.In a parallel study, evidence was found of carry-over effects of habitat age and prior exploitation on adult longevity for A. triseriatus and Aedes japonicus collected from unmanipulated aquatic habitats.These results indicate the importance of detritus dynamics and the discontinuous nature of resource competition in these mosquito-dominated aquatic systems.

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Seasonal Differences in Density But Similar Competitive Impact of Aedes albopictus (Skuse) on Aedes aegypti (L.) in Rio de Janeiro, Brazil

Cited by 41 publications

References 54 publications

Finding the sweet spot: What levels of larval mortality lead to compensation or overcompensation in adult production?

Finding the sweet spot: What levels of larval mortality lead to compensation or overcompensation in adult production?

Zika Virus: What Have We Learnt Since the Start of the Recent Epidemic?

The roles of history: age and prior exploitation in aquatic container habitats have immediate and carry‐over effects on mosquito life history

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