Field of Study – Zoology (N 014)

A meeting of the Commission for Admission to Doctoral Studies in the Field of Zoology science (N 014) with participation of applicants (motivational interviewing) will be held at the Conference Hall of Nature Research Centre on 12 September, 14:00 P.M. (online available too). Motivational interviewing will be conducted on the topic the applicant selected for his/her doctoral studies and thesis; applicants are recommended to deliver a 10 min duration PowerPoint presentation and give a brief review of planned research and scientific achievements. The interview and presentation will be evaluated taking into consideration the applicant’s scientific competence (publications, participation in scientific research projects and conferences), motivation in selecting the topic of the thesis, and primary methodological skills.

Carabid beetles can effectively control the abundance of pests and weed seeds in agroecosystems. Their role as biocontrol (BC) agents is especially significant if agricultural practices aim to move towards more environmentally-friendly food production. The acceleration of the transition to a sustainable food system is emphasized in the new Farm to Fork Strategy of the EU. This EU food system strategy aims to achieve neutral or positive environmental impact, mitigate and adapt to climate change, reverse biodiversity loss, ensure food security and public health, etc. In contrast, conventional agriculture is highly susceptible to climate change (e.g., climatic extremes, such as high temperatures) and applies many synthetic agro-chemicals which both may disrupt carabid beetle efficiency while providing BC service. Furthermore, even practices allowed to apply in organic farming might potentially have negative consequences for carabid beetle functioning: for example, polyethylene coverings are used as mulch which can be source of microplastics in agricultural soils. These anthropogenic factors (pesticides, high temperatures, microplastics) may act solely as well as interactively to further deteriorate carabid BC service. Up to date, such interactive effects (but also individual effects of e.g. microplastics) were not investigated and mechanistic understanding on beneficial predatory arthropods is yet to be revealed.

The proposed project aims to evaluate individual and interactive effects of high temperature (mimicking climatic extremes), pesticides and microplastics on the functioning of carabid beetles. Here carabid beetle functioning will be expressed as locomotor activity (Sub-study 1) and selective food consumption (Sub-studies 2 – 3).

The project includes three sub-studies:

1. Interactive and individual effects of pesticides and temperature on carabid beetle locomotor activity. These lab experiments will reveal if different pesticides have negative effects on carabid movement activity and whether these negative effects increase with higher temperature. Locomotor activity will be recorded with computer-centered video-tracking system.

2. Increased temperatureand pesticide interactiveeffects on macronutrient selection (food intake and nutrient balancing) of carabid beetles. In these lab experiments pesticides which showed the effect on locomotor activity in sub-study 1 will be applied. Carabid beetles will be treated with pesticides and increased temperature and will be served with semi-artificial diets with different macronutrient content (lipid-, protein- and sugar- rich diets). Here we would also evaluate what are changes in body macronutritional content and body dry weight after treatments.

3. Microplastic effects on nutritional physiology of carabid beetles. This experiment will show the effect of microplastics that potentially present in the environment on nutrient balancing of carabid beetles. Do microplastics have any nutritional “meaning” to carabid beetles? Part of the beetles will be served with clean semi-artificial foods and another part with the same foods mixed with small known amount of microplastic powder.

Helminths parasitizing the blood circulatory organs of birds, terrestrial mammals and freshwater fish are of great economic, veterinary and medical importance, including avian schistosomes whose cercariae cause human cercarial dermatitis and fish helminths causing mass deaths of fish. It is impossible to predict and effectively control the populations of these parasites and their spread, because the life cycles of most of them are not known. Identification of these species is based only on morphological studies of adults obtained from definitive hosts. Given the wide variety of definitive and intermediate hosts, the actual number of helminth species parasitizing the circulatory system should be higher. The real number of helminth species and the range of hosts, as well as their life cycles, can only be determined by molecular studies. In Europe, six genera of schistosomes use waterfowl as definitive hosts. As a result of climate warming, reports of avian schistosomal cercarial dermatitis are increasing in association with changes in snail distribution and density. However, there are no published data on the diversity and distribution of bird schistosomes in Lithuania and other countries of the Baltic region. In Lithuania and neighboring countries, four species of Sanguinicola are known to parasitize the circulatory organs of fish, but none of the species has been confirmed by molecular tests. This research is planned to collect helminths parasitizing the circulatory organs of vertebrates and gastropod molluscs in Lithuania and other countries of the Baltic Sea region. The main focus will be on assessing the genetic diversity of helminths by comparing at least three different nuclear and mitochondrial DNA sequences. These studies will allow the assessment of phylogenetic and phylogeographic relationships; linking the development stages of helminths found in different hosts to reveal their life cycles and the true specificity of the parasites. Cooperation with parasitologists from Scandinavia, Poland and Ukraine is also planned. It is expected to discover and describe new species of helminths.

Haemosporidian parasites are remarkably diverse, with the global number of species potentially exceeding that of their hosts. Understanding the drivers of this diversity are important for understanding the evolution of vector-borne diseases, as well as for the implications of infection for host individuals, which seems to vary between parasite species. However, different methods of identifying and classifying parasites differ markedly in their estimations of parasite species diversity, and so the assignation of parasite genetic lineages or morphotypes to species remains unresolved.

Molecular techniques using PCR protocols targeting a cytochrome b barcode have dramatically increased the accessibility of the study of haemosporidians to a wide range of research groups globally, but morphological study is still essential for our understanding of parasite ecology. Marrying molecular and morphological techniques is key to our understanding of parasite ecology because we know that cryptic genetic diversity is present within parasite morphospecies, but the extent to which this genetic diversity is ecologically important is unknown.

This project will firstly collate existing data on parasites from the genus Haemoproteus (Haemosporida, Haemoproteidae), where morphological and molecular data are available. Second, additional morphological analyses will be conducted on infections that have been characterised molecularly but not morphologically. Third, the project will determine the levels of cryptic molecular diversity within morphotypes and, using phylogenetic analysis, confirm whether molecular lineages within the same morphotype cluster phylogenetically. Using this information, it may be possible to test additional molecular markers to determine whether cytochrome b is the most appropriate marker to delineate Haemoproteus species, or to test whether ecological inferences obtained from molecular lineage data (e.g. host range, host relatedness) correlate with those obtained from morphological species definitions.

This study will contribute new knowledge about possible mechanisms of speciation in Haemoproteus pathogens and might ultimately contribute to improvement of bird health and wildlife conservation policies.

Over the years, avian haemosporidian parasites (Haemosporida: Haemoproteidae, Leucocytozoidae, Plasmodiidae) have attracted much attention from researchers working in various fields of science. These parasites have been extensively studied from the perspective of taxonomy, genetic diversity, ecology, evolutionary biology and genetics. However, knowledge of the full life cycle, particularly the exo-erythrocytic development, for the vast majority of described species remains fragmentary or even unknown. For example, until recently, parasites of the genus Haemoproteus were considered relatively benign to their vertebrate hosts, thus not much attention was dedicated to their pathogenicity. However, thanks to newly developed molecular diagnostics tools, it was shown that avian haemoproteids can and do develop exo-erythrocytic stages in vital organs including the brain of the infected individuals. There is a glaring lack of knowledge of the biology of this diverse group of widespread avian pathogens, preventing us from understanding the true effect these organisms have on their vertebrate hosts. Investigation of the exo-erythrocytic development of haemosporidian parasites is challenging, and it is particularly true when talking about wildlife research, where co-infections of parasite species belonging to the same and/or different genera predominate. It is unclear how such co-infection might influence bird health. Therefore, a combination of modern PCR-based techniques, phylogenetic methods, microscopy analysis, histopathological investigation, chromogenic in situ hybridization and laser capture microdissection approaches are cornerstone methodologies in addressing these alarming questions, which are related to bird health. A PhD candidate will master these methodologies. Fieldwork will be essential for parasite sample collection. The aim of the project is to obtain new knowledge on the exo-erythrocytic development of avian haemosporidian parasites during natural infections in wild birds. This project will examine wild naturally infected birds using a combination of the aforementioned modern approaches. We aim to add new fundamental data about avian haemospordian parasite biology, with particular focus on the exo-erytrhocytic development of these pathogens during various co-infections. Such data is key in better understanding the host-parasite interaction, epidemiology and pathologies caused by these parasites. It is expected that this project will result in: i) new knowledge on Haemoproteus, Leucocytozoon and Plasmodium parasite life cycles during development in organs; ii) better understanding of host-parasite and parasite-parasite interaction from the point of view of exo-erythrocytic development during co-infections; iii) vital knowledge on the pathogenicity of different haemosporidian lineages; iv) new data on morphological and molecular characterization of haemosporidians. It is expected that formerly unknown bird pathologies during haemosporidiosis might be unravelled. This research might ultimately contribute new ideas how to improve bird health and wildlife conservation policies. It is planned that a PhD candidate would have an opportunity to learn the most advanced parasite genetic diagnostic methods in leading European research institutions.

The geographically isolated Mediterranean region distinguishes by a high level of endemicity; it is one of the most important centres of biodiversity, where southern species and the “typical” fauna of central and northern Europe meet. It was one of refugia during the last glaciation, and it strongly influenced the European fauna as the climate became warmer and glaciers retreated.
Diptera is one of the three most abundant orders of insects, with more than 150,000 described species. This is one of the most progressive groups that changed and evolved intensively, occupying new ecological niches in the Cenozoic. Taxonomically, they are among the most complex insects, wherefore they are rather poorly investigated. Crane flies (Diptera, Tipuloidea) encompass over 10 percent of species of the order, which constitutes nearly 16 thousand; however, they are still poorly investigated compared to taxonomically “simpler” and easier describable groups. The eastern part of the Mediterranean basin has a complex terrain and potentially hides many undiscovered taxa, which can be demonstrated by museums material belonging to other groups of crane flies, e.g. Tipulidae family.
The Limoniinae sub-family crane flies are rather small and fragile, and their systematics is understudied because of the most complicated description among all Tipuloidea insects. The Limoniinae fauna of the Italian mainland and islands was studied, but studies were fragmentary and unsystematic. A considerable amount of material is accumulated in the collections of European museums; however, a large part of it is not described or analysed. The preimaginal stages, which most accurately represent ecological attachment and are crucial for phylogenetic analysis of the group, are hardly investigated.
It is planned to systematise material accumulated in museums (Italian, Swiss, Dutch museums), to collect new material with the help of Malaise and light traps and entomological nets, as well as to take samples of soil and coastal macroinvertebrates of water bodies; adult insects will be described and analysed, and unknown preimaginal stages will be reared to the adult insect stage or linked to adults by using molecular methods.
During research, the species composition of insects of the Limoniinae subfamily will be determined and compared with earlier data, ecological attachment analysis will be performed, and the phylogenetic position of individual groups will be specified.