Molecular Mechanisms Underlying Wing Color Pattern Development In Vanessa Cardui And Evolution Of The Polycomb Repressive Complex 2

In this dissertation, I present four papers. Three explore different aspects of wing color pattern development in the painted lady butterfly, Vanessa cardui; while the fourth examines the evolution of an epigenetic silencer complex across invertebrate animals. In the first paper, I used transcriptomics to identify patterning genes from the Drosophila wing gene regulatory network (GRN) in larval and pupal wings of V. cardui and to examine how temporal expression dynamics of this gene network correspond to expression of ommochrome and melanin pigment genes. This study identified key developmental periods of gene upregulation and highlights the temporal separation between peak expression of patterning and melanin pigment genes. In the second paper, I present evidence that hind wing eyespots of V. cardui exhibit phenotypic plasticity. Using morphometrics, I quantified how temperature shock and heparin modify eyespot size and pigment ring composition. This information is used to examine whether eyespot plasticity was a function of trait integration or modularity. In the third paper, I used qPCR to explore the role that epigenetic mechanisms may play in phenotypic plasticity of V. cardui eyespots. I examined expression of an epigenetic silencer, the polycomb repressive complex (PRC) in developing wings and in modified eyespots at 6 days post-pupation. I present evidence that the PRC is expressed during butterfly wing development and exhibits a similar pattern of expression to the wing GRN. Polycomb genes were not differentially expressed in eyespots modified by temperature shock and heparin sulfate; however, expression of several patterning genes was altered by these treatments. In the final paper, I present a comprehensive phylogenetic analysis of the PRC2 across non-vertebrate animals. This analysis revealed that the evolutionary history of the PRC2 does not reconstruct the known phylogeny of animals, due to significant sequence divergence in the nematode lineage. Thus, PRC2 has undergone significant evolutionary changes in nematodes that may be a consequence of Hox gene depletion and re-organization in this lineage

Physiological Perturbation Reveals Modularity of Eyespot Development in the Painted Lady Butterfly, Vanessa cardui

Butterfly eyespots are complex morphological traits that can vary in size, shape and color composition even on the same wing surface. Homology among eyespots suggests they share a common developmental basis and function as an integrated unit in response to selection. Despite strong evidence of genetic integration, eyespots can also exhibit modularity or plasticity, indicating an underlying flexibility in pattern development. The extent to which particular eyespots or eyespot color elements exhibit modularity or integration is poorly understood, particularly following exposure to novel conditions. We used perturbation experiments to explore phenotypic correlations among different eyespots and their color elements on the ventral hindwing of V. cardui. Specifically, we identified which eyespots and eyespot features are most sensitive to perturbation by heat shock and injection of heparin—a cold shock mimic. For both treatments, the two central eyespots (3 + 4) were most affected by the experimental perturbations, whereas the outer eyespot border was more resistant to modification than the interior color elements. Overall, the individual color elements displayed a similar response to heat shock across all eyespots, but varied in their response to each other. Graphical modeling also revealed that although eyespots differ morphologically, regulation of eyespot size and colored elements appear to be largely integrated across the wing. Patterns of integration, however, were disrupted following heat shock, revealing that the strength of integration varies across the wing and is strongest between the two central eyespots. These findings support previous observations that document coupling between eyespots 3 + 4 in other nymphalid butterflies

Geographic Variation in Host-Specificity and Parasitoid Pressure of an Herbivore (Geometridae) Associated with the Tropical Genus Piper (Piperaceae)

The extraordinary diversity of tropical herbivores may be linked to hostplant specialization driven in part by variation in pressure from natural enemies. We quantified levels of host-specificity and parasitoid attack for the specialist herbivore, Eois (Geometridae). The goals of this research were to examine: 1) whether Eois are specialized on the genus Piper (Piperaceae) and if hostplant specialization varies geographically; 2) whether Eois are equally vulnerable to parasitoid attack across different geographic regions and by the same parasitoid families; and 3) whether parasitism levels vary with precipitation and elevation. Based on over 15,000 rearings, we found Eois caterpillars feeding exclusively on Piper. However, we did not detect geographic differences in host-specificity; each Eois species fed on an average of two Piper species. Parasitism levels of Eois varied significantly with climate and topography; Eois were most vulnerable to parasitoid attack in moist versus dry and wet forests and at low versus high elevations. The diversity of parasitoid families reared from Eois was greater in Ecuador and Costa Rica than in Panama, where parasitoids were primarily in the family Braconidae. The quantitative evidence for host-specificity provides support for the hypothesis that Eois are specialized on Piper. Our results also reveal that Eois are exposed to a mosaic of potential selective pressures due to variation in parasitoid attack over a large spatial scale

Butterfly eyespots evolved via co-option of the antennal gene-regulatory network

Butterfly eyespots are beautiful novel traits with an unknown developmental origin. Here we show that eyespots likely originated via co-option of the antennal gene-regulatory network (GRN) to novel locations on the wing. Using comparative transcriptome analysis, we show that eyespots cluster with antennae relative to multiple other tissues. Furthermore, three genes essential for eyespot development (Distal-less (Dll), spalt (sal), and Antennapedia (Antp)) share similar regulatory connections as those observed in the antennal GRN. CRISPR knockout of cis-regulatory elements (CREs) for Dll and sal led to the loss of eyespots and antennae, and also legs and wings, demonstrating that these CREs are highly pleiotropic. We conclude that eyespots likely re-used the ancient antennal GRN, a network previously implicated also in the development of legs and wings

Butterfly eyespots evolved via cooption of an ancestral gene-regulatory network that also patterns antennae, legs, and wings

Butterfly eyespots are beautiful novel traits with an unknown developmental origin. Here we show that eyespots likely originated via cooption of parts of an ancestral appendage gene-regulatory network (GRN) to novel locations on the wing. Using comparative transcriptome analysis, we show that eyespots cluster most closely with antennae, relative to multiple other tissues. Furthermore, three genes essential for eyespot development, (), (), and (), share similar regulatory connections as those observed in the antennal GRN. CRISPR knockout of -regulatory elements (CREs) for and led to the loss of eyespots, antennae, legs, and also wings, demonstrating that these CREs are highly pleiotropic. We conclude that eyespots likely reused an ancient GRN for their development, a network also previously implicated in the development of antennae, legs, and wings

The Early Stages and Natural History of Antirrhea Adoptive Porphyrosticta (Watkins, 1928) in Eastern Ecuador (Lepidoptera: Nymphalidae: Morphinae)

Here we describe the immature stages and ecological associations of Antirrhea adoptiva porphyrosticta Watkins, 1928 (Lepidoptera:Nymphalidae:Morphinae). The cloud forest bamboo, Chusquea scandens Kunth (Bambusoidea: Poaceae), serves as the larval food plant for this butterfly in eastern Ecuador, the first hostplant record for Antirrhea outside the family Arecaceae. The larvae of A. adoptiva porphyrosticta are superficially similar to those of other Antirrhea species. We also provide observations on adult and larval behavior. Caterpillars of this butterfly species are parasitized by tachinid flies, as well as by Ichneumonidae and a newly described braconid wasp

A high-coverage draft genome of the mycalesine butterfly <i>Bicyclus anynana</i>

The mycalesine butterfly Bicyclus anynana, the "Squinting bush brown," is a model organism in the study of lepidopteran ecology, development, and evolution. Here, we present a draft genome sequence for B. anynana to serve as a genomics resource for current and future studies of this important model species. Seven libraries with insert sizes ranging from 350 bp to 20 kb were constructed using DNA from an inbred female and sequenced using both Illumina and PacBio technology; 128 Gb of raw Illumina data was filtered to 124 Gb and assembled to a final size of 475 Mb (∼×260 assembly coverage). Contigs were scaffolded using mate-pair, transcriptome, and PacBio data into 10 800 sequences with an N50 of 638 kb (longest scaffold 5 Mb). The genome is comprised of 26% repetitive elements and encodes a total of 22 642 predicted protein-coding genes. Recovery of a BUSCO set of core metazoan genes was almost complete (98%). Overall, these metrics compare well with other recently published lepidopteran genomes. We report a high-quality draft genome sequence for Bicyclus anynana. The genome assembly and annotated gene models are available at LepBase (http://ensembl.lepbase.org/index.html)

Borda rule as an alternative to other types of ordinal majoritarian electoral systems

This thesis focuses on the less studied electoral systems, which are called ordinal. These methods allow the voters to order the candidates according to their preferences. The work provides a historical insight into this issue with regard to economics and political science theories, based on the concept of the Condorcet winner. Condorcet winner is the person who defeats all other candidates in pairwise elections and by theorists of the electoral system is the ability to choose the Condorcet winner essential. The work examines three electoral methods - alternative and suplementary vote and Borda rule. These electoral systems are analyzed in terms of effects to system of political parties, political actors and the electorate, with the emphasis on the utilization rate of preferential votes. These aspects are examined on the basis of the actual election results obtained from the website of the electoral commissions and independent institutions. Based on these data, a mathematical model that compares the effects of electoral systems is then created. The conclusion summarizes the results of the analysis and the author expresses further recommendations to address these electoral methods, not only professionally and scientifically, but also as real alternatives for real election

Plosives in Czech: temporal characteristics and variability in realization

The aim of this diploma thesis is to closely investigate and describe selected phonetic properties of Czech oral plosives [p t ť k b d ď g] in normal speech. The re- search focuses mostly on temporal characteristics in various contexts; moreover, we deal with the possible manners of plosive articulation in Czech, including non-canonical realizations. Another important part of the present study is a comparison with earlier studies. In the domain of temporal characteristics we examine the influence of various contexts on phone duration. The contexts include: phonetic context, speaker gender, the position of the plosive in the stress unit or articulation rate. We also examine a possible connection between the duration of the plosive and its realization. In the part that deals with the manner of articulation we focus on the individual phonetic properties, for which we investigate especially the conditions and degree of their stability. Furthermore we describe the specific plosive articulations in certain pho- netic contexts and some alternative realizations of certain plosives. The speech material used is mostly spontaneous. All the speakers are non- professionals from various TV broadcasts. Keywords: plosives, duration, phone segmentation, phonetic properties, pho- netic context, gender, articulation..