Fitness Landscapes Reveal Context-dependent Benefits of Oviposition Choice

Abstract

Resource choice behaviour has enormous fitness consequences and can drive niche expansion. However, individual behavioural choices are often mediated by past experience. Are such context-dependent behaviours adaptive? Using the red flour beetle, we demonstrate that context-dependent oviposition choice indeed reflects distinct, context-specific local fitness peaks. Manipulating female egg allocation in a habitat containing optimal and novel resource patches, we measured offspring fitness to generate fitness landscapes as a function of all possible oviposition behaviours (i.e. combinations of fecundity and resource preference). Females from different age and density contexts exhibit distinct behaviours that optimize different fitness components. With increasing age and experienced population density, they produce few but fast-developing offspring that are advantageous under high resource competition; whereas young naive females produce many slow-developing offspring, which is beneficial under weak competition. Systematically mapping complete context-dependent fitness landscapes is thus critical to infer behavioural optimality, and offers predictive power in novel contexts.

Pathogen Growth and Virulence Dynamics Drive the Host Evolution Against Coinfections

“…We used a large, outbred population of Tribolium castaneum ( 72 ) adapted to laboratory conditions for >2 years before commencing the experiments (see SI for more details on baseline population maintenance and assays described below). Also, based on the observations from other experiments ( 32 , 73 ), we chose two naturally relevant bacterial entomopathogens that are likely to show contrasting growth dynamics and rates of virulence manifestations within insect hosts: fast-growing B. thuringiensis DSM2046 (Bt) ( 74 ) vs slow-growing P. entomophila L48 (Pe) ( 75 ), causing a rapid vs slower onset of mortality respectively.…”