Biology subjects

Montejo-Kovacevich, G.

Publications and source records attributed to Montejo-Kovacevich, G..

11 recordsLinked to original sources

bioRxiv2025

The collision of two genomes threatens global food security

Human activity alters selection pressures and redistributes biodiversity, creating opportunities for hybridization when dilerent species come into secondary contact. It is now well-established that ancient hybridization plays an important role in adaptive radiation 1, but its role in recent anthropogenic adaptation remains unclear. We investigated this in a study of hybridizing native and invasive Helicoverpa moths in Brazil, which are among the most economically damaging crop pests globally. Native H. zea has recently evolved Bt resistance and is better adapted to maize as a host plant, while invasive H. armigera is resistant to pyrethroid pesticides and is better adapted to soybean. Using a decade-long time series of 975 genomes from both species, we demonstrate rapid, bidirectional adaptive introgression of structural variants that cause resistance to two distinct pesticides. In one direction, a pyrethroid resistance gene from H. armigera (CYP337B3) is now almost fixed in native H. zea. In the other direction, ~30% of recently-sampled invasive H. armigera carry a H. zea-derived trypsin repeat cluster. Using controlled crosses, we show that this trypsin repeat cluster confers resistance to Bt (Cry1Ac) soy in the H. armigera genomic background. Thus, hybridization has combined H. armigera adaptation to soy with H. zea Cry1Ac resistance to facilitate exploitation of Brazilian Bt soy monoculture -- a vast anthropogenic habitat exceeding the area of Germany. Our results show that the combinatorial mechanisms that produce biodiversity can also drive rapid anthropogenic adaptation on ecological timescales, with consequences for global food security.

evolutionary biology↗

bioRxiv2025

Disentangling local adaptation and phenotypic plasticity in traits associated with altitude and temperature in widespread tropical butterflies

Climatic stratifications, in particular differences in temperature, occur along altitudinal clines. Understanding genetic and phenotypic divergence across these regions can give insight into speciation and diversification, as well as aid in our knowledge of how species may respond to possible climate change scenarios. Most past research has focused on temperate regions, yet it is in the tropics that organisms are thought to be the most vulnerable to rising temperatures. In addition, year-round stable temperatures in the tropics make altitudinal temperature variation more pronounced and increase the likelihood of local adaptation across relatively narrow gradients. Here we investigate how genetics and the environment influence a wide range of traits in two butterfly species, Heliconius erato and Heliconius melpomene, which are widespread across the neotropics and occur along the altitudinal slope of the Andes. Using common garden rearing of over 1,000 offspring from over 70 wild females caught along an altitudinal gradient, as well as rearing of populations from either end of the altitudinal range in their reciprocal temperature environments, we find evidence of genetic, environmental, and in some cases gene-by-environment interaction effects in developmental, morphological, and thermal tolerance traits. We find parallel divergence in wing colour in both species, with wing colour darkening with increasing altitude, consistent with this playing a role in thermoregulation in these species where wing colour has mostly been linked to mimicry and mate choice. We also find evidence for gene-by-environment interactions: In H. erato we found local differences in heat acclimation response, with increased heat knock-out times at higher rearing temperatures found only in low altitude populations, which are exposed to the hottest temperatures. We find evidence for heritable genetic variation in most traits measured, with positive implications for adaptation to climate change, although our results suggest that selection may not act in a straightforward way on these traits.

ecology↗

bioRxiv2024

The genetic architecture of resistance to flubendiamide insecticides in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

Insecticide resistance is a major problem in food production, environmental sustainability, and human health. The cotton bollworm Helicoverpa armigera is a globally distributed crop pest affecting over 300 crop species. H. armigera has rapidly evolved insecticide resistance, making it one of the most damaging pests worldwide. Understanding the genetic basis of insecticide resistance provides insights to develop tools, such as molecular markers, that can be used to slow or prevent the evolution of resistance. We explore the genetic architecture of H. armigera resistance to a widely used insecticide, flubendiamide, using two complementary approaches: genome-wide association studies (GWAS) in wild-caught samples and quantitative trait locus (QTL) mapping in a controlled cross of susceptible and resistant laboratory strains. Both approaches identified one locus on chromosome 2, revealing two SNPs within 976 bp that can be used to monitor field resistance to flubendiamide. This was the only region identified using linkage mapping, though GWAS revealed additional sites associated with resistance. Other loci identified by GWAS in field populations contained known insecticide detoxification genes from the ATP-binding cassette family, ABCA1, ABCA3, ABCF2 and MDR1. Our findings revealed an oligogenic genetic architecture, in contrast to previous reports of monogenic resistance associated with the ryanodine receptor. This work elucidates the genetic basis of rapidly evolving insecticide resistance and will contribute to the development of effective insecticide resistance management strategies. Author summaryInsecticide resistance in agricultural pests challenges food security, environmental sustainability, and human health. The cotton bollworm Helicoverpa armigera is resistant to various insecticide classes as well as Bacillus thuringiensis toxins. Understanding the genetic basis of this resistance is crucial for developing effective insecticide resistance management (IRM) strategies. Our study investigated the genetic architecture of resistance of H. armigera to flubendiamide and identified SNPs associated with resistance. We used two approaches: association mapping in wild-derived samples and QTL mapping in a controlled backcross of susceptible and resistant laboratory strains. One specific region on chromosome 2 was found in both GWAS and QTL mapping analysis and showed significant potential as a PCR-based marker for monitoring resistance to flubendiamide in H. armigera. Additionally, the GWAS identified five more SNPs in the field populations. The candidate genes identified are primarily associated with insecticide detoxification mechanisms and calcium homeostasis. Our study advances the understanding of the complex genetic architecture of flubendiamide resistance in H. armigera, providing valuable tools for IRM programs and establishing a basis for future studies.

genetics↗

bioRxiv2023

Sex chromosome - autosome fusions in Heliconius butterflies

Sex chromosomes are evolutionarily labile in many animals and sometimes fuse with autosomes, creating so-called neo-sex chromosomes. Fusions between sex chromosomes and autosomes have been proposed to reduce sexual conflict and to promote adaptation and reproductive isolation among species. Recently, advances in genomics have fuelled the discovery of such fusions across the tree of life. Here, we discovered multiple fusions leading to neo-sex chromosomes in the sara/sapho clade of the classical adaptive radiation of Heliconius butterflies. Heliconius butterflies generally have 21 chromosomes with very high synteny. However, the five species in the sapho subclade show large variation in chromosome number ranging from 21 to 60. We found that the W chromosome is fused with chromosome 4 in all of them. Two sister species pairs showed subsequent fusions between the W and chromosomes 9 or 14, respectively. These sequential fusions between autosomes and sex chromosomes make Heliconius butterflies an ideal system for studying the role of neo-sex chromosomes in adaptive radiations and the degeneration of sex chromosomes over time. Our findings emphasize the capability of WGS technology to detect neo-sex chromosomes even when sex chromosomes are not explicitly assembled. Author SummaryFusions between sex chromosomes and autosomes are thought to have the potential to resolve sexual conflict and enhance local adaptation or reproductive isolation between species. Here, we discovered such fusions in Heliconius butterflies. Heliconius butterflies mostly have a very stable karyotype with 21 chromosomes and high synteny across species. However, the five species in the sapho subclade have up to 60 chromosomes, suggesting that they have undergone many chromosomal fissions. We document that in addition to the fissions, the sapho subclade also showed multiple fusions between the female-specific sex chromosome (W) and autosomes. We found a W-4 fusion shared by all five species and additional W fusions with chromosomes 9 and 14 shared by two species each. Even though in many sapho subclade species the autosomes have undergone fissions, the chromosomes fused with the W represent the full-length autosomes, as seen in other Heliconius species, suggesting that fusing to the W protected them from fissions. Our study reveals the power of short-read sequencing to discover neo-sex chromosomes and showcases Heliconius butterflies as a promising system for studying the causes and consequences of sex chromosome evolution.

evolutionary biology↗

bioRxiv2022

Effects of temperature on the development of Heliconius erato butterflies

O_LIAnthropogenic climate change is thought to present a significant threat to biodiversity, in particular to tropical ectotherms, and the effects of long-term developmental heat stress on this group have received relatively little research attention. C_LIO_LIHere we study the effects of experimentally raising developmental temperatures in a tropical butterfly. We measured survival, development time, adult body mass, and wing size of a neotropical butterfly, Heliconius erato demophoon, across three temperature treatments. C_LIO_LIEgg survival was lower in the hotter treatments, with 83%, 73%, and 49% of eggs eclosing in the 20-30{degrees}C, 23-33{degrees}C, and 26-36{degrees}C treatments, respectively. Larval survival was five times lower in the 26-36{degrees}C treatment (4%) compared to the 20-30{degrees}C treatment (22%), and we did not detect differences in pupal survival across treatments due to high mortality in earlier stages. C_LIO_LIAdults in the 20-30{degrees}C treatment had a lower body mass and larvae had a lower growth rate compared to the intermediate 23-33{degrees}C treatment, but were heavier than the few surviving adults in the 26-36{degrees}C treatment. Females were heavier and grew faster as larvae than males in the 23-33{degrees}C treatment, but there was no associated increase in wing size. C_LIO_LIIn summary, high developmental temperatures are particularly lethal for eggs and less so for larvae, and also affect adult morphology. This highlights the importance of understanding the effects of temperature variation across ontogeny in tropical ectotherms. C_LI

zoology↗

bioRxiv2021

Repeated genetic adaptation to high altitude in two tropical butterflies

Repeated evolution can provide insight into the mechanisms that facilitate adaptation to novel or changing environments. Here we study adaptation to high altitude in two divergent tropical butterflies, H. erato and H. melpomene, which have repeatedly and independently adapted to high elevations on either side of the Andean mountains. We sequenced 518 whole genomes from elevational transects and found many regions under selection at high altitude, with repeated genetic differentiation across multiple replicates, including allopatric comparisons. In contrast, there is little molecular parallelism between H. erato and H. melpomene. With a further 85 whole genomes of five close relatives, we find that a large proportion divergent regions have arisen from standing variation and putative adaptive introgression from high-altitude specialist species. Taken together our study supports a key role of standing genetic variation and gene flow from pre-adapted species in promoting parallel genetic local adaptation to the environment.

evolutionary biology↗

bioRxiv2020

Genomics of altitude-associated wing shape in two tropical butterflies

Understanding how organisms adapt to their local environment is central to evolution. With new whole-genome sequencing technologies and the explosion of data, deciphering the genomic basis of complex traits that are ecologically relevant is becoming increasingly feasible. Here we study the genomic basis of wing shape in two Neotropical butterflies that inhabit large geographical ranges. Heliconius butterflies at high elevations have been shown to generally have rounder wings than those in the lowlands. We reared over 1100 butterflies from 71 broods of H. erato and H. melpomene in common-garden conditions and show that wing aspect ratio, i.e. elongatedness, is highly heritable in both species and elevation-associated wing shape differences are maintained. Genome-wide associations with a published dataset of 666 whole genomes from across a hybrid zone, uncovered a highly polygenic basis to wing shape variation in the wild. We identify several genes that have roles in wing morphogenesis or wing shape variation in Drosophila flies, making them promising candidates for future studies. There was little evidence for molecular parallelism in the two species, with only one shared candidate gene, nor for a role of the four known colour pattern loci, except for optix in H. erato. Thus, we present the first insights into the heritability and genomic basis of within-species wing shape in two Heliconius species, adding to a growing body of evidence that polygenic adaptation may underlie many ecologically relevant traits.

evolutionary biology↗

bioRxiv2020

High evolutionary potential in the chemical defenses of an aposematic Heliconius butterfly

Chemical defences against predators underlie the evolution of aposematic coloration and mimicry, which are classic examples of adaptive evolution. Surprisingly little is known about the roles of ecological and evolutionary processes maintaining defence variation, and how they may feedback to shape the evolutionary dynamics of species. Cyanogenic Heliconius butterflies exhibit diverse warning color patterns and mimicry, thus providing a useful framework for investigating these questions. We studied intraspecific variation in de novo biosynthesized cyanogenic toxicity and its potential ecological and evolutionary sources in wild populations of Heliconius erato along environmental gradients, in common-garden broods and with feeding treatments. Our results demonstrate substantial intraspecific variation, including detectable variation among broods reared in a common garden. The latter estimate suggests considerable evolutionary potential in this trait, although predicting the response to selection is likely complicated due to the observed skewed distribution of toxicity values and the signatures of maternal contributions to the inheritance of toxicity. Larval diet contributed little to toxicity variation. Furthermore, toxicity profiles were similar along steep rainfall and altitudinal gradients, providing little evidence for these factors explaining variation in biosynthesized toxicity in natural populations. In contrast, there were striking differences in the chemical profiles of H. erato from geographically distant populations, implying potential local adaptation in the acquisition mechanisms and levels of defensive compounds. The results highlight the extensive variation and potential for adaptive evolution in defense traits for aposematic and mimetic species, which may contribute to the high diversity often found in these systems.

evolutionary biology↗

bioRxiv2019

Microclimate buffering and thermal tolerance across elevations in a tropical butterfly

Microclimatic variability in tropical forests plays a key role in shaping species distributions and their ability to cope with environmental change, especially for ectotherms. Yet, currently available climatic datasets lack data from the forest interior and our knowledge of thermal tolerance among tropical ectotherms is limited. To tackle this, we studied natural variation in the microclimate experienced by a tropical genus of butterflies (Heliconius sp.) along their Andean range across a single year. We found that the forest strongly buffers temperature and humidity in the understory, especially in the lowlands where temperatures are more extreme. There were systematic differences between our yearly records and macroclimate databases (WorldClim2), with lower interpolated minimum temperatures and maximum temperatures higher than expected. We then assessed thermal tolerance of ten Heliconius butterfly species in the wild and showed that populations at high elevations had significantly lower heat tolerance than those at lower elevations. However, when we reared populations of the widespread H. erato from high and low elevations in a common-garden environment, the difference in heat tolerance across elevations was reduced, indicating plasticity in this trait. Microclimate buffering is not currently captured in publicly available datasets but could be crucial for enabling upland shifting of species sensitive to heat such as highland Heliconius. Plasticity in thermal tolerance may alleviate the effects of global warming on some widespread ectotherm species, but more research is needed to understand the long-term consequences of plasticity on populations and species. Summary statementTropical forests along the Andes were found to greatly buffer climate. The butterflies inhabiting high elevations were less thermally tolerant but not when reared in common-garden conditions, indicating plasticity.

ecology↗

bioRxiv2019

Altitude and life-history shape the evolution of Heliconius wings

Phenotypic divergence between closely related species has long interested biologists. Taxa that inhabit a range of environments and have known and diverse, natural histories, can help understand how different selection pressures shape diverging traits. In butterflies, wing colour patterns have been extensively studied, whereas wing shape diversity is less well understood despite its importance for flight. Here we study a measure of wing shape, aspect ratio, and wing size in a large dataset of over 3200 individuals, representing 13 Heliconius species, from across the Neotropics. We assess the relative importance of phylogenetic relatedness, natural history and habitat in determining wing shape and size. We find that both larval and adult behavioural ecology affect patterns of adult size dimorphisms. On one hand, species with solitary larvae have larger adult males, in contrast to gregarious Heliconius species, and indeed most Lepidoptera. On the other hand, species in the pupal-mating clade are smaller overall than those in the adult-mating clade. Interestingly, while controlling for phylogeny, sex ratios and allometry, we find that species inhabiting higher altitudes have rounder wings and, in one of the two major Heliconius clades, are also bigger in size than their lowland relatives. Thus, we reveal novel adaptive wing morphological divergence among Heliconius species beyond that imposed by natural selection on aposematic wing colouration. Our study highlights the value of phylogenetic comparative methods in study systems that have diverse and well-studied natural histories to disentangle the selection pressures shaping adaptive phenotypes.

evolutionary biology↗

bioRxiv2019

Species specificity and intraspecific variation in the chemical profiles of Heliconius butterflies across a large geographic range

In many animals, mate choice is important for the maintenance of reproductive isolation between species. Traits important for mate choice and behavioural isolation are predicted to be under strong stabilising selection within species, however such traits can also exhibit variation at the population level driven by neutral and adaptive evolutionary processes. Here, we describe patterns of divergence among androconial and genital chemical profiles at inter- and intra-specific levels in mimetic Heliconius butterflies. Most variation in chemical bouquets was found between species, but there were also quantitative differences at the population level. We found a strong correlation between interspecific chemical and genetic divergence, however, this correlation varied in intraspecific comparisons. We identified indicator compounds characteristic of particular species that included known biologically active compounds, suggesting an approach for identification of candidate compounds for future behavioural studies in novel systems. Overall, the strong signal of species identity suggests a role for these compounds in species recognition, but with additional potentially neutral variation at the population level.

evolutionary biology↗