A minimalist approach to the effects of density‐dependent competition on insect life‐history traits

Abstract

Abstract. 1. Due to its effects on the phenotypic and genotypic expression of lifehistory traits, density-dependent competition is an important factor regulating the growth of populations. Specifically for insects, density-dependent competition among juveniles is often associated with increased juvenile mortality, delayed maturity, and reduced adult size.2. The aim of the work reported here was to test whether the established phenotypic effects of density-dependent competition on life-history traits could be reproduced in an experimental design requiring a minimal number of individuals. Larvae of the mosquito Aedes aegypti were reared at densities of one, two, or three individuals per standard Drosophila vial and in six different conditions of larval food availability. This design required relatively few individuals per independent replicate and included a control treatment where individuals reared at a density of one larva per vial experienced no density-dependent interactions with other larvae.3. Increased larval densities or reduced food availability led to increased larval mortality, delayed pupation, and the emergence of smaller adults that starved to death in a shorter time (indicating emergence with fewer nutritional reserves).4. Female mosquitoes were relatively larger than males (as measured by wing length) but males tended to survive for longer. These differences increased as larval food availability increased, indicating the relative importance of these two traits for the fitness of each sex. The role of nutritional reserves for the reproductive success of males was highlighted in particular.5. This minimalist approach may provide a useful model for investigating the effects of density-dependent competition on insect life-history traits.

Effect of food types on competitive interaction between Aedes aegypti (LINNAEUS, 1762) and Ae. albopictus (SKUSE, 1894) (Diptera, Culicidae): a proximate level appraisal

“…Inter-and intraspecific competition between Ochlerolatus caspius and Culiseta longiareolata also showed a similar kind of response when the initial density was varied (TSURIM et al 2013). In separate studies, the effects of food on this competition resulted in differential responses by the two Aedes mosquitoes (AGNEW et al 2002, YEE et al 2004). Several studies have been conducted on competitive interactions between Ae.…”

“…aegypti and Ae. albopictus to a considerable extent (AGNEW et al 2002, JULIANO 2009 and can thus be considered a vital factor for disease transmission potential (ALTO et al 2008a(ALTO et al , 2008b. The disease transmission potential of dengue vectors is linked with the fitness of the mosquitoes (JULIANO et al 2014), reflected through body size and various life history traits that are influenced by larval development and the resources acquired during the larval stages.…”

“…In addition to numerical abundance, environmental factors like temperature (LOUNIBOS et al 2002, KIRBY & LINDSAY 2009, WESTBROOK et al 2010, COURET et al 2014, EWING et al 2016) and food resources (RENSHAW et al 1994, ARRIVILLAGA & BARRERA 2004 influence the outcome of larval development. The outcome of both interspecific and intraspecific competition influences the population dynamics of both these mosquito species, as is evident from different laboratory and field studies (AGNEW et al 2002, GAVOTTE et al 2009, GILLES et al 2011. Competitive effects can be evaluated through variations in life history traits like pupal weight, adult weight and wing length (AGNEW et al 2002, JULIANO 2009.…”

“…The outcome of both interspecific and intraspecific competition influences the population dynamics of both these mosquito species, as is evident from different laboratory and field studies (AGNEW et al 2002, GAVOTTE et al 2009, GILLES et al 2011. Competitive effects can be evaluated through variations in life history traits like pupal weight, adult weight and wing length (AGNEW et al 2002, JULIANO 2009. The life history traits in mosquitoes are determined by the larval feeding characteristics, which in turn depend on the resources available in their habitats.…”

“…aegypti and Ae. albopictus may compete for resources, the outcome of which may vary with the relative abundance of the two species in the larval habitats (AGNEW et al 2002, ARRIVILLAGA & BARRERA 2004, BÉDHOMME et al 2005, LEGROS et al 2009, REISKIND & LOUNIBOS 2009, ALTO et al 2015. In addition to numerical abundance, environmental factors like temperature (LOUNIBOS et al 2002, KIRBY & LINDSAY 2009, WESTBROOK et al 2010, COURET et al 2014, EWING et al 2016) and food resources (RENSHAW et al 1994, ARRIVILLAGA & BARRERA 2004 influence the outcome of larval development.…”