Biology subjects

Ravi Kumar, V.

Publications and source records attributed to Ravi Kumar, V..

4 recordsLinked to original sources

bioRxiv2026

Selection history alters fitness across ecological interactions in a fly-parasitoid system

Species interactions shape ecological dynamics, but adaptation to one interaction can trade off with others. Experiments that measure such evolved fitness changes across multiple interactions remain rare. We used experimental evolution to test whether recent selection under one ecological interaction changes fitness under other interactions in a fly-parasitoid system. We evolved a genetically diverse Drosophila melanogaster population for 15-17 generations under three regimes: benign conditions (control), high intraspecific competition, and infection by the parasitoid wasp Leptopilina boulardi. We then measured fly fitness (egg-to-adult survival and subsequent reproduction) under benign conditions, high intraspecific competition, and infection by three other parasitoid species and an additional conspecific L. boulardi strain. Selection history strongly influenced fitness across interactions. Populations maintained under high larval density showed reduced survival under infection by L. boulardi and L. victoriae, indicating a trade-off between past selection for competition and defence against some parasitoids. Populations evolved under parasitoid infection by L. boulardi showed increased resistance to a conspecific strain but reduced fitness when infected by another species, L. heterotoma. Our results show that rapid evolution in response to a single interaction can reshape multiple ecological interactions through fitness trade-offs, highlighting how recent evolutionary history may influence community dynamics and invasion susceptibility.

evolutionary biology↗

bioRxiv2025

Founders predict trait evolution and population dynamics after evolutionary rescue

Evolutionary rescue helps populations survive environmental change, but the phenotypic and demographic factors associated with rescue dynamics and its long-term effects remain unclear. We experimentally evolved 10 wild-collected populations of flour beetles from across India in a suboptimal corn resource for 70 generations (>5 years), collecting >10,000 population census points book-ended by measurements of fitness-related traits for 30 experimental lines. Despite clear ancestral trait differences, all lines showed highly parallel evolutionary rescue within 20 generations. Long-term average population size varied across source populations and was positively correlated with ancestral development rate, which increased convergently across populations and emerged as the single best predictor of population performance during and after evolutionary rescue. Notably, specific demographic events during rescue (such as the rate of population decline and recovery) were uncorrelated both with ancestral trait distributions and post-rescue adaptation. Our results support prior work showing founder traits as key predictors of adaptation, and highlight their role in long-term adaptation and trait evolution following evolutionary rescue. SIGNIFICANCE STATEMENTUnderstanding how populations adapt to sudden environmental change is vital given accelerating biodiversity declines, the rise of antimicrobial resistance and climate change. We chart evolutionary rescue -- where rapid adaptation prevents extinction -- in flour beetles across 70 generations. Using >10,000 census points and measuring fitness in ancestors, their offspring and in evolved lines, we show that larval development rate is the strongest correlate of long-term population success across diverse wild-collected populations. The effect of ancestral variation is dynamic and disassociated from finer-grained details of the rescue. All populations show highly parallel evolutionary rescue, with convergent evolution in key traits. These findings have direct implications for predicting species survival after environmental change, ranging from conservation to pest and pathogen management.

evolutionary biology↗

bioRxiv2021

Fitness Landscapes Reveal Context-Dependent Benefits of Oviposition Choice

Resource choice behaviour has enormous fitness consequences and can drive niche expansion. However, individual behavioural choices are often mediated by context, determined by past experience. Are such context-dependent behaviours adaptive? Using Tribolium castaneum (the red flour beetle), we demonstrate that context-dependent oviposition choice reflects distinct, context-specific local fitness peaks. Manipulating female egg allocation in a habitat containing optimal and suboptimal 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 competition contexts exhibit distinct behaviours which optimize different fitness components that are linked in a tradeoff. With increasing age and prior exposure to competition, they produce few but fast-developing offspring that are advantageous under high resource competition. In contrast, young naive females produce many slow-developing offspring, 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. Preprint available at - https://www.biorxiv.org/content/10.1101/2021.05.27.445916v1.full Citation - Vrinda Ravi Kumar, Gaurav Agavekar, Deepa Agashe; bioRxiv 2021.05.27.445916; doi: https://doi.org/10.1101/2021.05.27.445916

ecology↗

bioRxiv2018

The induction of larval resource preference in heterogeneous habitats

Animals often have to evaluate and choose between multiple food sources in their habitat, and these potentially complex decisions can have a large impact on their fitness. Among other factors, previous experience with an alternative resource can significantly increase subsequent preference for the resource (\"induction of preference\"). Such induction of resource preference is particularly relevant in spatially or temporally heterogeneous habitats. Although most mobile species - especially generalists - probably frequently encounter habitat heterogeneity, the impact of preference induction on individual behaviour and fitness in heterogeneous habitats is poorly understood. We analysed larval preference induction in wheat-adapted generalist red flour beetles (Tribolium castaneum) under three types of habitat heterogeneity. We first analysed the induction of larval preference for novel resources (other cereal flours) under temporal heterogeneity, exposing larvae to new resources during development. We found that larvae preferred a new resource if they experienced it recently, but that the magnitude of induction varied across resources. Interestingly, we also observed specific induction for a homogenous mix of wheat and a novel resource, with larvae preferring the mix over either pure resource. To analyse induction under spatial heterogeneity, we placed beetle eggs in one of two alternative resource patches and tested the preference of emerged larvae. Unexpectedly, hatching into a novel resource did not always induce preference. Finally, we found that induction of preference for new resources could be maladaptive for larval development. Together, our work demonstrates that experience-based plasticity of larval resource choice may strongly impact larval preference and fitness in heterogeneous habitats.

ecology↗