Biology

Density-dependent interactions within a complex life cycle: the roles of cohort structure and mode of recruitment

Document Type

Article

Abstract

Analysed the effects of cohort structure, density, egg hatch inhibition and cannibalism on estimated per capita growth rate (r′) in populations of Aedes triseriatus established in artificial habitats. As density increased from 0.5 K to 0.75 K to the estimated carrying capacity (K = 60 larvae per 100 ml), r′ decreased, along with other measures of success: survivorship, female size, and development rate. Cohort structure and recruitment schedule significantly influenced r′. Populations initiated as eggs achieved r′ values greater than cohorts started as first instar larvae and substantially greater than those populations consisting of single cohorts. There was no evidence for cannibalism in the experimental habitats, which were stocked with leaf detritus and treehole water. Egg-initiated cohorts exhibited the greatest developmental asynchrony during the first month of the experiment, whereas cohorts added as 2-day-old larvae displayed highly synchronized development. Increased competitive interactions in this latter treatment may explain the small size attained by adult females emerging from these populations. Differences among multiple cohort groups increased with increasing density. Results emphasize the need to incorporate overlapping stages into experimental designs for populations that develop asynchronously, and the value of using r′ as a descriptor of success rather than the individual components of success (eg survivorship, size, and development rate) which can lead to misinterpretations of productivity. -from Authors

Publication Title

Journal of Animal Ecology

Publication Date

1992

Volume

61

Issue

1

First Page

139

Last Page

150

ISSN

0021-8790

DOI

10.2307/5517

Keywords

cannibalism, density-dependent

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