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Kunte, K.

Publications and source records attributed to Kunte, K..

17 recordsLinked to original sources
bioRxiv2026

Negative Frequency-dependent Mimicry Governs Seasonal Population Dynamics of Batesian Mimics

Seasonal changes in climate, resources, and trophic interactions jointly shape prey population dynamics in ecological systems. In monsoon-driven tropical and subtropical landscapes, prey populations cycle between cool, wet, favourable periods during the rainy seasons and hot/cold, dry and sub-optimal conditions outside the rainy seasons, with resource availability and predation risk changing across seasons of the year. Defensive strategies and species interactions such as aposematism and Batesian mimicry are expected to interact with seasonal changes in resource availability and predation risk in determining population dynamics of prey species. Here we study population dynamics of mimetic butterfly community members using a 12-year long-term dataset from a subtropical urban forest in peninsular India. Our results show that climate and species interactions differentially influence population dynamics of different functional categories in mimetic butterfly communities, i.e., of aposematic species, mimetic and non-mimetic forms of mimetic species, and close relatives treated as ecological and phylogenetic contrasts. Population dynamics of non-mimetic species and forms were predominantly influenced by climate parameters such as temperature and precipitation, whereas population dynamics of mimics were more deeply impacted by mimetic interactions. Population dynamics of non-mimetic and mimetic forms of the same species showed distinct decoupling, with population dynamics of non-mimetic forms being similar to their non-mimetic relatives (phylogenetic contrasts). On the other hand, population dynamics of aposematic species and mimetic forms/species followed the predictions of negative frequency dependence and phase-shifting in mimicry theory: (a) mimetic forms/species were less abundant than their Batesian models, (b) the harmonic mean of populations of Batesian models influenced the upper limit of relative frequency of mimetic forms/species to a greater degree in these continuously breeding, seasonally fluctuating populations, and (c) populations of Batesian mimics peaked after population peaks of their Batesian models. These results reveal that climate and species interactions differentially determine population dynamics of prey species by functional categories at the community level, rather than by species identity and individual species attributes and resource demands.

ecology↗
bioRxiv2026

Dysregulation of pupal diapause in hybrid progenies, introgression and species delimitation within and beyond the Old World Swallowtail (Papilio machaon Linnaeus) butterfly complex

In search of recurrent patterns of postzygotic hybrid incompatibility, we investigated the Holarctic Old World Swallowtail (Papilio machaon Linnaeus) butterfly complex, whose members can easily be crossed in the laboratory. How many species this model system comprises remains unclear, as taxa with highly distinctive larvae but uncertain status come into contact with authentic P. machaon subspecies in Southern parts of the Palearctic region. By determining mitochondrial and ITS2 haplotypes within and away from contact zones, we found that these neighboring populations do exchange genes, as expected from F1 hybrids being generally fertile in our laboratory crosses. Nevertheless, recurrent instances of dysregulation of diapause were uncovered in hybrid progenies. In keeping with Haldanes Rule, pupae of the heterogametic (female) sex were either unable to enter diapause or, in reciprocal crosses, unable to resume development after having initiated diapause, whereas F1 males experienced normal, photoperiod-regulated diapause, but passed on abnormal diapause regulation to part of their female offspring when backcrossed. Comparing male and female pupal weights in hybrid progenies provides estimates of parental incompatibility that allow to rank taxa and predict quantitatively the outcome of additional crosses, as expected if the same regulatory system were involved. A survey of the entomological literature confirms that diapausing pupae that cannot resume development ( perpetual nymphs) are a recurrent feature of interspecific lepidopteran crosses. Moreover, of the two parent species of a perpetual nymph, the paternal one generally has fewer broods per year. These observations are discussed in the light of models of the speciation process.

evolutionary biology↗
bioRxiv2024

LONG-TERM ECOLOGICAL MONITORING IN INDIA: A SYNTHESIS

Long-term ecological monitoring (LTEM) is crucial for understanding ecological processes and responses to environmental change, informing management of natural resources, and biodiversity conservation. Systematic LTEM efforts began in India in the mid-1900s, but there is a lack of comprehensive synthesis of LTEM efforts in the country. Here, we use a wide-ranging questionnaire survey of ecologists coupled with a survey of published literature on LTEM efforts in India to synthesise their thematic and geographical spread, and types of data being collected, and identify key challenges to the establishment and maintenance of LTEM projects in the country. Studies monitor 77 unique subjects across 272 LTEM efforts in India. LTEM efforts are more often located in the Western Ghats and Eastern Himalaya, focused on forest vegetation, and monitoring factors such as abundance, distribution, species richness, and biomass. Regions such as North-Eastern, Eastern, Central, and North-Western India, ecosystems such as grasslands, deserts and wetlands, organisms such as macrofungi, amphibians, and reptiles (other than turtles) are underrepresented. Short turnover times of funding and permits were most frequently reported as hurdles in sustaining LTEM efforts. Data from LTEM efforts have been largely used to produce academic outputs such as journal articles, but have also found use for on-the-ground conservation efforts. Overall, this synthesis can help draw attention to the need for systematic long-term ecological monitoring, help efficient utilisation of existing long-term ecological data, identify regions, species and ecosystem components that are underrepresented in Indian LTEM efforts, foster collaborations, and serve as a starting point to address challenges in sustaining LTEM efforts in India.

ecology↗
bioRxiv2024

Evolution of novel mimicry polymorphisms through Haldanes sieve and rare recombination

Origins of phenotypic novelty represent a paradox. Maintenance of distinct, canalized morphs usually requires a complex array of polymorphisms, whose co-retention requires a genetic architecture resistant to recombination, involving inversions and master regulators. Here, we reveal how such a constraining architecture can still accommodate novel morphs in evolving polymorphisms using the classic polymorphic Batesian mimicry in Papilio polytes, whose supergene-like genetic architecture is maintained in a large inversion. We show that rapidly evolving alleles of the conserved gene, doublesex, within this inversion underlie the genetic basis of this polymorphism. Using precisely dated phylogeny and breeding experiments, we show that novel adaptive mimetic morphs and underlying alleles evolved in a sequentially dominant manner, undergoing selective sweeps in the mimetic species as predicted under Haldanes sieve. Furthermore, we discovered that mimetic forms share precise inversion breakpoints, allowing rare exon swaps between the universally dominant and a recessive allele to produce a novel, persistent intermediate phenotype, ultimately facilitating the acquisition of phenotypic novelty. Thus, genetic dominance, selective sweeps, rapid molecular divergence, and rare recombination promote novel forms in this iconic evolving polymorphism, resolving the paradox of phenotypic novelty arising even in highly constrained genetic architectures.

evolutionary biology↗
bioRxiv2024

Spectral variation and pigmentary basis of ornamental and mimetic wing colour patches of swallowtail butterflies

Colours and colour patterns are extraordinarily diverse traits that are often used as visual signals. To test ecological and evolutionary drivers of these visual signals, a clear understanding of their nature and variation is necessary. Here we characterise variation in wing colouration of Asian mormon swallowtail butterflies (Papilio, subgenus Menelaides). These species exhibit two kinds of colour patches on largely black wings: creamy white/yellow/green patches that are presumably used as sexual ornaments, and pure white patches that are presumably used as mimetic signals. Using reflectance spectrophotometry we quantified spectral properties of black wing background and colour patches between sexes, wing surfaces and mimicry status. We discovered that brightness and saturation of the black background were less variable across sexes, wing surfaces and mimetic/non-mimetic status. However, colour contrast and saturation were higher on dorsal surfaces than on ventral surfaces, and colour contrast between the black background and colour patches was higher in males than in females. Colour patches in non-mimetic butterflies were brighter and more saturated across the whole colour spectrum compared to mimetic butterflies. These patterns of colour variations in relation to their putative functions suggest that: (a) colour patches on dorsal and ventral wing surfaces evolve independently to accommodate differential strengths of natural and sexual selection, (b) sexual ornaments are brighter in non-mimetic males but they also occur in all non-mimetic females, indicating mutual sexual selection on these ornaments, but which is stronger in males, and (c) mimetic male and female butterflies display less sexual contrast in colour patches, indicating relatively similar strength of mimetic selection. Thus, our study characterises colour variation in an extraordinary signal radiation on the wings of swallowtail butterflies, a model clade in ecology, evolution and genetics. Finally, using liquid chromatography-mass spectrometry (LCMS) we identified the pigment papiliochrome-II to be the chemical basis of the presumed sexual ornaments in mormon swallowtails.

evolutionary biology↗
bioRxiv2022

Duplication and sub-functionalisation characterise diversification of opsin genes in the Lepidoptera

Gene duplication is a vital process for evolutionary innovation. Functional diversification of duplicated genes is best explored in multicopy gene families such as histones, hemoglobin, and opsins. Rhodopsins are photo-sensitive proteins that respond to different wavelengths of light and contribute to diverse visual adaptations across insects. While there are several instances of gene duplications in opsin lineages, the functional diversification of duplicated copies and their ecological significance is properly characterised only in a few insect groups. We examined molecular and structural evolution that underlies diversification and sub-functionalisation of four opsin genes and their duplicated copies across 132 species of the diverse insect order--Lepidoptera. Opsins have largely evolved under purifying selection with few residues showing signs of episodic and pervasive diversifying selection. Although these do not affect overall protein structures of opsins, substitutions in key amino acids in the chromophore-binding pocket of duplicated copies might cause spectral sensitivity shifts leading to sub-functionalisation or neofunctionalisation. Duplicated copies of opsins also exhibit developmental stage-specific expression in Papilio polytes, suggesting functional partitioning during development. Together, altered spectral sensitivities owing to key substitutions and differential expression of duplicated copies across developmental stages might enable enhanced colour perception and improved discrimination across wavelengths in this highly visual insect group.

evolutionary biology↗
bioRxiv2022

Diversification is correlated with temperature in white and sulfur butterflies

Temperature is thought to be a key variable explaining global patterns of species richness. However, to investigate this relationship carefully, it is necessary to study clades with broad geographic ranges that are comprised of species inhabiting diverse biomes with well- characterized species ranges. In the present study, we investigate the link between temperature and diversification in the butterfly family Pieridae (sulfurs and whites) by combining Next Generation sequences and published molecular data with fine-grained distribution information. After building the most comprehensive phylogeny of the group, with almost 600 species and all higher taxa (subfamilies, tribes and subtribes), we found strong support for the following relationships within the family: Dismorphiinae + (Coliadinae + (Pseudopontiinae + Pierinae)). With a curated distribution dataset of over 800,000 occurrences, we conducted multiple comparative phylogenetic analyses that provided strong evidence that species in environments with more stable daily temperatures or with cooler maximum temperatures in the warm seasons have higher diversification rates. We also found a positive correlation between speciation and extinction with paleotemperature: as global temperature decreased through geological time, so did diversification rates. Although many studies demonstrate higher diversity in the tropics, we have been able to identify specific climate variables associated with changes in diversification, while also inferring the most robust and well sampled phylogenomic framework for Pieridae to date.

evolutionary biology↗
bioRxiv2022

An interactive pipeline for multitrait evolutionary analysis in a phylogenetic framework

Comparative phylogenetic studies based on 2D image data can reveal macroevolutionary patterns and processes by integrating phylogenetic and ecological analyses. The advent of high-throughput imaging facilities has led to the accumulation of large image datasets; however, large-scale data extraction and analysis using these resources can be labour- and computation-intensive. Moreover, there are few standardized methods to analyse multitrait image-based data in a phylogenetic framework. Several packages in the R statistical environment offer utilities for processing and analysing large-scale image data. Techniques for the comparative phylogenetic analysis of multitrait data have also been introduced in other packages. However, most of these approaches are specialized for discrete purposes, and there is a lack of streamlined and efficient methodological pipelines integrating features across packages. Here, we present multEvol, an interactive pipeline for the extraction and phylogenetic analysis of shape and colour pattern data from 2D images in the R statistical computing environment. Using this pipeline, shape outlines and colour pattern data for multiple colours can be extracted, visualised, and compared in a phylogenetic framework. Using various utilities provided in the phytools, RNiftyReg, Momocs, patternize, convevol, and geiger packages, we introduce an interactive interface that allows user inputs for iterative data extraction. This pipeline provides an efficient method for the bulk processing of images of biological specimens from museum collections. As such, it has potential applications in the large-scale morphometric analysis of museum specimens to reveal macroevolutionary patterns in ecology, evolution and integrative biology.

evolutionary biology↗
bioRxiv2022

Polytypy and systematics: diversification of Papilio swallowtail butterflies in the biogeographically complex Indo-Australian Region

A long-standing problem in evolutionary biology and systematics is defining patterns of diversification and speciation, which is compounded by allopatric distributions of polytypic taxa in biogeographically fragmented landscapes. In this paper we revisit this enduring systematic challenge using Mormon swallowtail butterflies (Papilio subgenus Menelaides)--an evolutionary and genetic model system. Menelaides is speciose and intensively sampled, with nearly 260 years of systematic study complicated by polytypy resulting from discontinuous morphological variation. This variation is structured by the mainland-island matrix of the geologically complex Indo-Australian Region, where drawing species boundaries has been difficult. We sampled variation across the biogeographic range of Menelaides, covering 97% of currently recognized species and nearly half of all subspecies. We generated a well-supported mito-nuclear phylogeny, on which we delineated species based on two species delimitation methods (GMYC and mPTP) and strongly supported reciprocal monophyly. These analyses showed that the true species diversity in this group may be up to 25% greater than traditional taxonomy suggests, and prompts extensive taxonomic restructuring. Biogeographic analyses showed that Menelaides have diversified largely in allopatry in Indo-Australian subregions by repeated dispersals across key biogeographic barriers. These results provide critical insights into the diversification process in this morphologically diverse and taxonomically complicated model group. These results will also be informative in future studies on systematics, biogeography, speciation and morphological diversification in the Indo-Australian Region--arguably the most complex geological land/seascape in the world.

evolutionary biology↗
bioRxiv2022

Reproductive barriers and genomic hotspots of adaptation during allopatric species divergence

Theory predicts that in allopatric populations, genomic divergence and reproductive barriers will be driven largely by random genetic drift, and thereby evolve slowly in large populations. However, local adaptation and divergence under selection may also play important roles, which remain poorly characterised. Here we address three key questions in young allopatric species: (a) How widespread are genomic signatures of adaptive divergence?, (b) What is the functional space along which young sister species show divergence at the genomic level?, and (c) How quickly might prezygotic and postzygotic reproductive barriers evolve? Analysis of 82 re-sequenced genomes of the Oriental Papilio polytes species group revealed surprisingly widespread hotspots of intense selection and selective sweeps at hundreds of genes unique to each species, and spanning all chromosomes, rather than divergence only in a few genomic islands. These genes perform diverse ecologically important adaptive functions such as wing development, colour patterning, courtship behaviour, mimicry, pheromone synthesis and olfaction, and host plant use and digestion of secondary metabolites, that could contribute to local adaptation and subsequent reproductive isolation. Divergence at such functional genes appeared to have reproductive consequences: behavioural and hybridisation experiments revealed strong assortative mate preference (prezygotic barriers) as well as postzygotic barriers to hybridisation in timespans as short as 1.27 my, indicating that speciation was already complete, rather than incipient. Our study thus demonstrates an underappreciated role of intense selection and potential local adaptation in creating genome-wide hotspots of rapid molecular evolution and divergence, during differentiation and speciation in young allopatric species.

evolutionary biology↗
bioRxiv2022

Seasonal dynamics and polyphenism of butterfly communities in the coastal plains of central Western Ghats, India

Long-term socioeconomic progress requires a healthy environment/ecosystem, but anthropogenic activities cause environmental degradation and biodiversity loss. Constant ecological monitoring is therefore necessary to assess the state of biodiversity and ecological health. However, baseline data is lacking even for ecologically sensitive regions such as the Western Ghats. We looked at the seasonality and polyphenism of butterflies of the central Western Ghats to get baseline population patterns on these charismatic taxa. We recorded 43118 individuals (175 species) using fortnightly time-constrained counts for two consecutive years, and found the peak abundance (49% of the total individuals) in post-monsoon period (Oct to Jan). The seasonal abundance was correlated with the overall increase in species richness. Habitat differences were stronger than seasonality as samples clustered based on sites. Several species also displayed polyphenism with distinct distributions of wet and dry season forms. Seasonal equitability and indicator species analysis showed distinct inter-species differences in seasonality patterns. This work provides key baseline data on the seasonal dynamics of butterflies of the Western Ghats in the context of climate change and conservation, and will help in future monitoring of this ecologically sensitive region using butterflies.

ecology↗
bioRxiv2021

A comparison between time-constrained counts and line transects as methods to estimate butterfly diversity in tropical habitats

Long-term species monitoring programmes have revealed catastrophic insect population declines and disruption of biological communities that are contributing to biodiversity loss. Such discoveries have been possible because of standardised methods, such as line transects, of counting butterflies and other insects. However, line transects are not feasible in many tropical and mountainous habitats, so alternative methods must be explored. To tackle this issue, we devised time-constrained (30-min) counts and compared butterfly diversity as estimated through this method with that estimated through line transects in three tropical habitats in India (evergreen forest, dry deciduous forest and an urban woodland). We tested the efficacy of the two methods to sample species richness and abundance, as well as numbers of rare, endemic and specialist butterflies. We observed greater species richness, and more species of habitat specialists and endemics per sample in time-constrained counts in evergreen forest, but not in the other two habitats. Thus, time-constrained counts were more efficient at detecting species in the species-rich evergreen habitat. Apart from this difference, the two sampling methods captured similar levels of species richness and other measures of diversity. Our study thus shows that time-constrained counts is a suitable if not a superior alternative to line transects to conduct butterfly diversity surveys and population monitoring in complex tropical landscapes. Due to methodological flexibility and simplicity, this method may be particularly useful to study the impacts of climate change, habitat fragmentation and land use practices on butterfly conservation in populous and tech-ready tropical countries using citizen science frameworks.

ecology↗
bioRxiv2020

Molecular evolution and developmental expression of melanin pathway genes in Lepidoptera

Pigmentation is involved in a wide array of biological functions across insect orders, including body patterning, thermoregulation, and immunity. The melanin pathway, in particular, has been characterized in several species. However, molecular evolution of the genes involved in this pathway is poorly characterized, and their roles in pigmentation of early developmental stages are just beginning to be explored in non-model organisms. We traced the molecular evolution of six melanin pathway genes in 53 species of Lepidoptera covering butterflies and moths, and representing over 100 million years of diversification. We compared the rates of synonymous and nonsynonymous substitutions within and between these genes to study signatures of selection at the level of individual sites, genes, and branches of the gene tree. We found that molecular evolution of all six genes was governed by strong purifying selection. Yet, a number of sites showed signs of being under positive selection, including in the highly conserved domain regions of three genes. Further, we traced the expression of these genes across developmental stages, tissues, and sexes in the Papilio polytes butterfly using a developmental transcriptome dataset. We observed that the expression patterns of the genes in P. polytes largely reflected their known tissue-specific function in other species. The expression of sequentially acting genes in the melanin pathway was correlated. Interestingly, four out of six melanin pathway genes (ebony, pale, aaNAT, and DDC) showed a sexually dimorphic pattern of developmental heterochrony; i.e., females showed peak activity much earlier in pupal development compared to that of males. Our evolutionary and developmental analyses suggest that the vast diversity of wing patterning and pigmentation in Lepidoptera may have been aided largely by differential developmental regulation of genes in a highly conserved pathway, in which the sequence evolution of individual genes is highly constrained.

evolutionary biology↗
bioRxiv2019

Disrupting butterfly microbiomes does not affect host survival and development

Associations with gut microbes play a crucial role in the physiology, immune function, development, and behavior of many insects. However, butterflies may be an exception to this pattern since butterfly microbiomes do not show the host-specific and developmental shifts that are expected to evolve under strong host-microbial associations. Here, we present the first experimental test of this hypothesis by disrupting gut microbial communities of two butterfly species, Danaus chrysippus and Ariadne merione. Larvae of both the species fed on host plant leaves that were either chemically sterilized or treated with antibiotics had significantly reduced bacterial loads and disrupted gut bacterial communities substantially. However, neither host species treated this way suffered a significant fitness cost. We did not find significant variation in survival, growth and development between test larvae and control larvae. This suggested that butterflies do not rely on their gut bacteria for digestion, detoxification, resource accumulation and metamorphosis. Thus, our results provide empirical support for the growing realization that dependence on gut bacteria for growth and survival is not a universal phenomenon across insects.

ecology↗
bioRxiv2019

Predictability in the evolution of Orthopteran cardenolide insensitivity

The repeated evolutionary specialisation of distantly related insects to cardenolide-containing host plants provides a stunning example of parallel adaptation. Hundreds of herbivorous insect species have independently evolved insensitivity to cardenolides, which are potent inhibitors of the alpha-subunit of Na+, K+-ATPase (ATP). Previous studies investigating ATP-mediated cardenolide insensitivity in five insect orders have revealed remarkably high levels of parallelism in the evolution of this trait, including the frequent occurrence of parallel amino acid substitutions at two sites and recurrent episodes of duplication followed by neo-functionalisation. Here we add data for a sixth insect order, Orthoptera, which includes an ancient group of highly aposematic cardenolide-sequestering grasshoppers in the family Pyrgomorphidae. We find that Orthopterans exhibit largely predictable patterns of evolution of insensitivity established by sampling other insect orders. Taken together the data lend further support to the proposal that negative pleiotropic constraints are a key determinant in the evolution of cardenolide insensitivity in insects. Furthermore, analysis of our expanded taxonomic survey implicates positive selection acting on site 111 of cardenolide-sequestering species with a single-copy of ATP, and sites 115, 118 and 122 in lineages with neo-functionalised duplicate copies, all of which are sites of frequent parallel amino acid substitution.

evolutionary biology↗
bioRxiv2017

DIETARY AND DEVELOPMENTAL SHIFTS IN BUTTERFLY-ASSOCIATED BACTERIAL COMMUNITIES

Bacterial communities associated with insects can substantially influence host ecology, evolution and behavior. Host diet is a key factor that shapes bacterial communities, but the impact of dietary transitions across insect development is poorly understood. We analyzed bacterial communities of 12 butterfly species across different development stages, using 16S rDNA amplicon sequencing. Butterfly larvae typically consume leaves of a single host plant, whereas adults are more generalist nectar feeders. Thus, we expected bacterial communities to vary substantially across butterfly development. Surprisingly, very few species showed significant developmental transitions in bacterial communities, suggesting weak impacts of dietary transitions across butterfly development. On the other hand, bacterial communities were strongly influenced by butterfly species identity and dietary variation across species. Larvae of most butterfly species largely mirrored bacterial community composition of their diets, suggesting passive acquisition rather than active selection. Overall, our results suggest that although butterflies harbor distinct microbiomes across taxonomic groups and dietary guilds, the dramatic dietary shifts that occur during development do not impose strong selection to maintain distinct bacterial communities.

ecology↗