We performed crosses between blue and black subspecies of both species and used these to identify regions of the genome responsible for colour variation. Firstly, Melanie Brien used photographs to quantify colour variation between individuals. Juan Enciso-Romero, then used x-ray scattering data from the European Synchrotron Radiation Facility to quantify variation in the scale structures.
In Heliconius erato we largely find a single genomic region that controls variation in both blue colour and scale structure. This is on the sex-determining Z chromosome (males have two copies of this chromosome while females just have one)
In Heliconius melpomene, by contrast, we find that quantified colour differences are associated with variation on chromosome 3, while variation in scale structure is associated with chromosome 7. These results suggest that the two species have convergently evolved similar colour using different genetic mechanisms.
To try to find which genes in these genomic regions were controlling structural colour, Victoria Lloyd then compared the level of expression of genes within this mapped genomic regions. Using developing wing tissue from blue and black butterflies, she looked for genes that were expressed at a higher level in the blue wings. Interesting candidates include genes that are part of or interact with the cell cytoskeleton, which might have a role in shaping the structures.
This work is a first step in understanding how biological systems make and control structural colours. Something that humans have been trying to replicate for decades, with limited success.
We are seeking an enthusiastic student with interests in ecology and evolution to work on a project investigating the evolution of wing scale nanostructures and thermal adaptation in tropical Andean butterflies. The wings of butterflies are covered in thousands of scales that have evolved to serve a range of functions including aerodynamic efficiency, colour signalling, camouflage, hydrophobicity and thermoregulation. Fundamental to these functions is the nanostructure of the scales.
Interest in organisms’ adaptation to their thermal environment has grown in recent years as we try to understand and predict how organisms will respond to climate change. Butterflies are one of the best-studied insect groups with respect to thermal adaptation. While the importance of the wings for thermoregulation has been known for some time, only recently has the importance of the wing scale nanostructures begun to be appreciated.
The project can be tailored to the interests of the student but would likely include working with museum collections of butterflies at the Natural History Museum (under the supervision of Dr Huertas), using cutting-edge techniques for measuring scale nanostructure (under the supervision of Dr Parnell) and computational analysis to investigate ecological correlates of wing scale nanostructure (under the supervision of Dr Thomas). It could also involve fieldwork in South America to obtain further butterfly specimens, ecological data and/or test hypotheses about thermal adaptation. This project builds on recent work in Dr Nadeau’s research group investigating the evolution, genetics and development of butterfly wing scale nanostructures and thermal adaptation in tropical Andean butterflies. The outcomes of this project could have applications in the design of nanomaterials to improve the thermal efficiency of man-made structures such as windows and solar panels.
We are looking for two postdoctoral research associates to work on a NERC-funded project “The genetic basis of convergence across evolutionary time” led by Dr Kanchon Dasmahapatra at the University of York and Dr Nicola Nadeau at the University of Sheffield.
This project seeks to understand how the genetics of convergent evolution differs with differing evolutionary timescales. We will determine whether the genetic mechanism of convergence (collateral evolution, parallel evolution and divergent genetic mechanisms) depends on the relatedness of the species, the effect size of the loci involved and/or conservation of the genetic pathways controlling the phenotype. In South America there are mimicry rings in which many defended species converge on near identical colour patterns. This project will investigate the genetic basis of convergent mimicry in wing patterns among 18 species of butterflies and moths, which include the well-studied Heliconius butterflies. This is a unique system in the Lepidoptera in which we know that some recently diverged lineages have converged in defensive colouration by collateral evolution, whereas other clades have achieved similar phenotypes despite diverging over 100 million years ago. This provides an ideal model system in which to explore the likelihood of different mechanisms of convergence among lineages at a range of evolutionary timescales.
One of the PDRAs will be based in Sheffield, supervised by Nicola Nadeau. This postdoc will lead the bioinformatic analysis of population genomic and gene expression data sets to identify genes controlling within-species colour-pattern variation in multiple species of ithomiine butterflies and Chetone day-flying moths.
Closing date: 29th September 2021. Start Date: 1st November 2021 (negotiable).
The second PDRA will be employed by the University of York and supervised by Kanchon Dasmahapatra. This postdoc will work in Peru and Ecuador (with our partner, Caroline Baquet, at IKIAM University), collecting samples, breeding stocks of these species and assessing gene expression in situ. This position will be advertised shortly, to start in April 2022.
We are recruiting a 40% FTE (14hrs/week) Research Technician on our newly funded Human Frontier Science Program grant investigating the genetics and biomechanics of butterfly wing scale development. This international and interdisciplinary project brings together expertise in physics and materials science with genetics and developmental biology to understand how intricately patterned nanostructures form on butterfly wings during development. An essential part of this project, which the technician would have primary responsibility for, is the maintenance of the butterfly stocks and the plants that they feed on at the University of Sheffield.
Primarily, the technician will be responsible for day-to-day maintenance of stocks of the butterfly Heliconius sara and their Passiflora host plants, and other butterfly species such as Vanessa cardui (the painted lady). They will also be responsible for coordinating others to assist with the necessary day-to-day maintenance tasks. The position may also involve some molecular laboratory tasks such as preparing solutions, dissecting, fixing, staining and imaging developing butterfly wings and preparing protein and RNA extracts. Although a 12-month position in the first instance, the research grant is for three years, and the technician’s contract would likely be renewed for the duration of the grant. We ideally want someone interested in staying for the full 3-year duration.
Applicants should have experience in and an enthusiasm for working with insects and plants, with good organisational and problem-solving skills. Previous experience working in a laboratory environment is also essential.
In a new paper out in Molecular Ecology, we investigate the genetic basis of wing shape variation in two tropical butterfly species, Heliconius erato and Heliconius melpomene. We have previously shown that, both within and between species, butterflies from higher altitude in the Andes tend to have rounder wings. In the current paper we show that this difference within these two species is genetically controlled and we identify some of the genes that might be responsible.
These results tell us that there are genetic differences between populations of butterflies found at different elevations in the Andes, and that some of these differences are likely to be important for adapting them to the different environmental challenges they face at different heights in the mountains.
This is part of our NERC funded project on adaptation to altitude in tropical insects. It was led by Gaberiela Montejo-Kovacevich as part of her PhD. Much of the rearing work in Ecuador was led by Postdoctoral research associate Patricio Salazar working with our partners at Ikiam University.
We are excited to be part of a new Human Frontier Science Programme project starting in October 2021 to investigate the genetics and biomechanics of butterfly wing scale structure formation.
During the final stage of metamorphosis, butterfly wings sprout with hundreds of thousands of scales, each formed by a single cell and carrying precise chitin-based nanostructural motifs. Delicate control of scale structure on the single-scale level determines multiple functions of the wing, including brilliant colors, water repellency, thermoregulation, and lift generation. Despite these functions being of great interest to biologists and engineers alike, we only have limited knowledge of the mechanisms underlying scale formation. This project takes inspiration from nature, to understand how functional nano-structures are assembled in butterfly wing scales from a biological, physical and engineering perspective.
This research, published in the Journal of Evolutionary Biology, started out as Masters project by Hannah Bainbridge. She investigated vairation in the size and shape of the red band found on the wing of two butterfly species that mimic each other, Heliconius erato and Heliconius melpomene. These two species are known to use the same major-effect genes to control major differences in colour and pattern that are found between popualtions, but more subtle variation has not been investigated to the same extent. We find that this variation is also controlled by some of the same major-effect genes, but overall the two species largely seem to use different genes to control it.
We have a new paper out in Molecular Ecology where we investigate variation in iridescent structural colour in the mimetic butterflies Heliconius erato and Heliconius melpomene. Both of these species vary from having to blue iridescent colour in Colombia to being matt black in Panama.
In her PhD thesis work Emma Curran showed that the colour change is more gradual in H. melpomene than H. erato and this is most likely due to weaker selection acting on the colour in this species. She also investigated population genomic structure and fund that while H. erato clusters into two different groups in Panama and Colombia, H. melpomene doesn’t. While the colour change happens in a similar place in both species, strongly suggesting that mimicry between the species has been important in its evolution, the differences between species hint at different evolutionary histories.
This is the first time that variation in iridescent structural colour has been investigated in wild Heliconius populations. This trait is also different to the colour pattern traits that have most commonly been investigated in Heliconius because it is a quantitative trait, controlled by many loci, rather being controlled by a single genetic locus. Our results therefore also shed light on the major question of how differences in quantitative traits evolve.