Denstity Dependence in Insect Host‐Parasitoid Systems: A Comment

Brown, Mark

doi:10.2307/1940227

Cited by 19 publications

(12 citation statements)

References 17 publications

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“…Although parasitism by multiple parasitoid species could lead to a confounding effect in the detected outcome of density dependence (Brown 1989), here we found a clear pattern for the community, which seems to be the result of the action of the dominant species. Larvae in leaves with many leaf mines were less likely to be parasitized than larvae in leaves with few conspecifics, which was contrary to our expectation of observing direct density dependence.…”

Section: Discussioncontrasting

confidence: 56%

A hierarchical multi‐scale analysis of the spatial relationship between parasitism and host density in urban habitats

et al. 2017

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Studies on spatial density dependence in parasitism have paid scarce attention to how changes in host density at different hierarchical scales could influence parasitism in an herbivore at a particular scale. Here, we evaluated if rates of parasitism per leaf (by the whole parasitic complex and by dominant species) of the specialist leaf miner Liriomyza commelinae (Diptera: Agromyzidae) respond to variations in host density at the leaf, plant patch and site levels in an urban setting. We used multi-level Bayesian models that incorporate the spatial hierarchy occurring in this system, as well as habitat factors previously found to have an effect on the L. commelinae parasitoid community in an urban context (patch size, patch isolation and urbanization level). According to the fitted model, overall parasitism rates decreased with increasing number of mines per leaf, being independent of host-density variations at patch and site level. Patch structure was found to have a strong effect on parasitism rates per leaf. The analysis of parasitism by parasitoid species separately showed consistent results with the response at community level. These results suggest that parasitism of the parasitoid community here studied would be sensitive to hierarchical cues related to the host at the leaf level and to the host habitat at the patch level.

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Section: Discussioncontrasting

confidence: 56%

A hierarchical multi‐scale analysis of the spatial relationship between parasitism and host density in urban habitats

et al. 2017

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“…1990, Turchin 1990, Cappuccino 1992, Woiwod and Hanski 1992. The measured impact of density dependence in any particular species can depend on behavioral or ecological details of the system, as well as the methods and spatial scale employed by the investigation (Brown 1989, Stiling et al 1991, Woiwod and Hanski 1992.…”

Section: Resultsmentioning

confidence: 99%

Population Consequences of Larval Crowding in the Dragonfly Aeshna Juncea

Buskirk¹

1993

Ecology

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I studied sources of density dependence in a dragonfly population to reveal how population size is controlled. Larvae of the dragonfly Aeshna juncea, inhabiting rock pools on the Lake Superior shoreline at Isle Royale, Michigan, USA, showed clear evidence of competition when natural densities were high. After 2 yr of larval growth, individuals in crowded pools were developmentally delayed and survived less well than individuals in sparsely populated pools. The stunted larvae caught up with individuals in less crowded pools and reached the final instar in sufficient time to emerge in the summer of their 3rd yr, but even so their final body size remained relatively small. A 5—wk field experiment in natural pools demonstrated the causal connection between density and fitness: feeding activity and growth rates were significantly reduced under crowded conditions, but survival showed no response to density. In unmanipulated rock pools, however, natural increases in density from one year to the next were met with slightly overcompensatory decreases in annual survival. The results illustrate that density dependence operates in a way that could contribute to population regulation in A. juncea, and a 6—yr time series from one of the two study areas showed significant evidence for density—dependent dynamics.

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“…Ecological factors such as the dynamics of natural enemies and fluctuations in resource availability are considered by many authors to be important factors in animal population regulation (e.g., Dempster and Pollard 1981, Turchin 1990). Models that fail to include such important regulation factors or their various influences on population dynamics may not be able to detect different types of density dependence, such as indeterminate density dependence, which may contain density‐dependent, inversely density‐dependent, and density‐independent processes (Strong 1986, Brown 1989). These various types of density dependence may operate at different times and under different density ranges in nature (Nicholson 1958, Strong 1986, Sinclair 1989).…”

Section: Discussionmentioning

confidence: 99%

Complex Population Dynamics in the Real World: Modeling the Influence of Time-Varying Parameters and Time Lags

Zeng

Nowierski

Taper

et al. 1998

Ecology

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We propose a class of complex population dynamic models that combines new time‐varying parameters and second‐order time lags for describing univariate ecological time series data. The Kalman filter and likelihood function were used to estimate parameters of all models in the class for 31 data sets, and Schwarz’s information criterion (SIC) was used to select the best model for each data set. Using the SIC method, models containing density‐dependent processes were selected for 23 of the 31 cases examined, while models containing complex density‐dependent processes were selected in 19 of these 23 density dependence cases. The density‐dependent models identified by SIC had various linear or nonlinear forms, suggesting variable patterns of population regulation in nature. Population dynamics may combine density‐dependent, inversely density‐dependent, and density‐independent processes, which may operate at different times and under different density ranges. These results suggest that our approach offers an advance for modeling complex population dynamics, discovering complex regulation processes, and estimating the distribution of extinction times in changing environments.

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Denstity Dependence in Insect Host‐Parasitoid Systems: A Comment

Cited by 19 publications

References 17 publications

A hierarchical multi‐scale analysis of the spatial relationship between parasitism and host density in urban habitats

A hierarchical multi‐scale analysis of the spatial relationship between parasitism and host density in urban habitats

Population Consequences of Larval Crowding in the Dragonfly Aeshna Juncea

Complex Population Dynamics in the Real World: Modeling the Influence of Time-Varying Parameters and Time Lags

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