Ullasa's pre-IISER projects
This page has information about my (Ullasa's) work in Stockholm University and University of Cambridge prior to joining IISER-TVM. Much of the current work in our group draws from and continues upon these research topics. To sum up my research so far - I have been interested in understanding evolutionary patterns in butterflies. With this overarching interest, phylogenetic and phylogeographic information has been directly or indirectly part of much of my work. Processes create patterns, and I have hence also been interested in experimental work to understand these. I started my PhD looking into the phylogenetics and biogeographic patterns within the family Nymphalidae. Along the way, I got interested in wing-pattern evolution, evolution of host-plant preferences, Wolbachia- butterfly interactions, etc. I worked on butterflies in the genus Polygonia, trying to understand evolution of host-plant preferences across populations. My most recent work has been on mycalesine butterflies (Nymphalidae: Mycalesina), investigating patterns of speciation and underlying mechanisms.
I have worked largely on butterflies of the family Nymphalidae. Nymphalid butterflies are one of the most important invertebrate model systems, due mainly to their high ecological & morphological diversity and the vast amount of baseline information on their natural history.
The mycalesine radiation
The mycalesines are a recent rapid radiation of ca. 300 species comprising three groups of approximately equal numbers in the African mainland, Madagascar and tropical Asia. This includes the well-studied African species Bicyclus anynana. As part of my postdoctoral stint with Paul Brakefield's group at Cambridge - Radiating Butterflies, I was involved in several studies seeking to understang diversification patterns and processes among mycalesine butterflies. This is an ongoing project and we are continuing to investigate components of diversfication including biogeography, wing-pattern evolution, host-plant interactions and secondary sexual characters.
Phylogeography and evolution of host-plant preferences
My postdoc work with Sören Nylin, Niklas Janz and Elisabet Weingartner. We studied the phylogeographic structure and patterns of geneflow among populations of Polygonia c-album and P. faunus using mitochondrial and microsatellite markers. We tested hypotheses of evolution of host-plant preferences of populations.
I studied the evolution of eyespot number and position over the phylogeny of Junonia and related genera. This group has a diversity of eyespot patterning, ranging from a single eyespot to more than 6. Additionally, there is variation in the position where eyepots are found. This allowed me to test hypotheses of eyespot pattern evolution and the study has opened up a few questions on the development and evolution of eyespots. This project got me more deeply interested in eyespot evolution and led to further experimental work on different species with various collaborators. For instance we showed that eyespots in Junonia almana enhance surivival by thwarting attacks from birds. I have other projects on Inachia io and Coenonympha butterflies.
Collaborators in my eyespot work include Christer Wiklund, Adrian Vallin, Sami Merilaita's group, Magne Friberg and Martin Olofsson.
Wolbachia in nymphalids.
I have been assaying species across Nymphalidae, and especially within Polygonia for the presence of the cytoplasmic bacterial parasite Wolbachia. These parasites are well known for their effects on hosts –sex-ration distortion, cytoplasmic incompatibility and feminization. I am interested in understanding the extent of infection at the global and local scales, strain diversity of these bacteria and their effects on the host population structures. Apart from Polygonia species, I have been looking at this in Coenonympha tullia (with Felix Sperling and Thomas Simonsen) and the endangered Lopinga achine (with Karl Gotthard).
Phylogenetics and Biogeography
Like many other naturalists, I entered scientific research after an intial fascination for the study group - in my case, butterflies. And nymphalid systematics proved to be my bridge between amateur allure and a lifetime scientific vocation. Biogeography was of course a natural extension of phylogenetic systematics, and my PhD thesis work, with Niklas Wahlberg, was on these two aspects. All my phylogenies have relied on molecular data. Groups I worked on: Junonia, Coenonymphina, Mycalesina (on which I continue to work on for my postdoc). I have also been involved in investigations into higher-level systematics of Nymphalidae and Satyrinae, projects of Niklas Wahlberg and Carlos Peña.
I have been studying how the geographic ranges of butterflies (and other groups) have evolved over time, and the historical factors that led to such changes. Having used various analytical methods in historical biogeography, I have also had a chance to publish a couple of papers critiquing (positive and negative!) some of these methods.
At the outset, research was merely an excuse to be in the field looking for birds, butterflies, herps, etc... Naturally, the most enjoyable parts of my research are the field trips I am able to go on and indulge myself in the name of science. Additionaly, some of the places in NE India I have been visiting have not been systematically surveyed for butterflies for some time now, and spot records I obtained will help update the current distributional status for several species.
1. Western Ghats, South India - I have spent a few weeks here each year as part of my annual 'pilgrimage', mainly in Karnataka and Kerala.
2. Spain - Apr, 2007.
3. Laos - Oct, 2007.
4. Sikkim, NE India - Apr, 2008.
5. Mizoram, NE India - Oct-Nov, 2008.
6. Indonesia - May, 2009.
7. Sikkim and Assam - Oct-Nov, 2009.
8. Philippines and Thailand - Jul-Aug, 2011.
9. Malaysia - Nov-Dec, 2011.