Transmission of genes for cilour polymorphism in Philaenus

Nimekkeen selvennys: Brief Reports..

Genetics of Philaenus colour polymorphism: the 28 genotypes.

Nimekkeen selvennys: Brief reports.vo

Changing climate and the Baltic region biota

The Baltic region is characterised by a strong seasonal climate. Climate change may bring profound ecological changes in the region. These ecological responses to a changing climate can be better understood if the effects of recent yearly variations are known. Other ways to explore possible consequences to future climate change are by using climate models and by looking at the response of species to a warmer climate during the past millennia. This thesis utilizes these methods including a range of study species: a mammal, migratory birds, and an insect. The mammalian species studied is the Baltic ringed seal (Pusa hispida botnica), a subspecies of the ringed seal. Ringed seals need ice as a substrate for breeding, including the construction of a breeding lair. It is shown (study I) that the projected changes in the ice climate for 2071–2100 in the southern breeding areas (the Gulf of Finland, the Archipelago Sea and the Gulf of Riga) are so large, that for most years successful breeding is unlikely. In the northernmost parts of the Bothnian Bay, the ice climate is still projected to be suitable for breeding for most years. By the end of this century, it is possible that the Bothnian Bay will be the only remaining breeding area for the Baltic ringed seal. Based on an extensive material of subfossil seal finds, study (II) suggests that ringed seals have probably lived continuously in the Baltic Sea for more than 10,000 years, even surviving the Holocene Thermal Maximum (a several millennia-long warm period). As the warm winters of the Holocene probably weren't as warm as the temperatures projected for the final decades of this century, the survival prospects of the ringed seal in the Baltic will probably be reduced in a way unprecedented in the history of the subspecies. The bird study (III) adds to the growing evidence that temperatures along migration routes have an effect on arrival times. We found negative correlations between temperature and arrival times in several of the ten studied long-distance Finnish migrants, indicating that birds arrive earlier when the temperature is higher along the migration route. Temperature data used in studies of bird spring migration phenology often comes from the breeding grounds. As the correlation between the timing of migration and temperature, in this and other studies, is often located along the migration route (several hundreds of kilometres away from the breeding grounds), the responsiveness of bird spring migration timing to temperature change may be underestimated. The possibility of long-distance migrants using temperature to predict yearly variations in the advancement of spring in the breeding area and the relationships of changes between distribution and phenology are discussed. The dominating source of large-scale climate variability in Europe, the North Atlantic Oscillation (NAO), had an impact on the population dynamics of the spittlebug (Philaenus spumarius), a common insect (study IV). We also show that winter NAO affects nymph mortality in the Tvärminne study area of Southern Finland. A relatively stationary lagged effect of winter NAO on mid-spring temperature was found in the Baltic area. As the lagged effect of winter NAO on spring temperatures in Northern Europe is well documented in meteorological literature, I propose that such lagged effects of winter NAO can, in many cases, be behind the associations found between winter NAO and spring migration phenology of long-distance bird migrants in Europe.Työssä tutkitaan ilmastonmuutoksen ja ilmaston vaihtelun vaikutuksia eliölajien ekologiaan Itämeren alueella. Laajimmin käsitelty tutkimuskohde on itämerennorppa. Norpat lisääntyvät helmi–maaliskuussa. Poikanen syntyy jään päälle, normaaleissa oloissa erityiseen pesään, jossa emä imettää sitä yli kuukauden. Ilmastonmuutos vähentää tutkimuksen mukaan jääpeitteisen ajan kestoa Itämerellä. Itämerennorpan nykyisistä poikimisalueista Suomenlahden, Saaristomeren ja Riianlahden jääpeite heikkenee pesimisympäristönä voimakkaasti tämän vuosisadan loppuun mennessä. Johtopäätöksenä on, ettei norppa todennäköisesti selviydy näillä eteläisillä pesimäalueillaan, jos ilmastonmuutoksen toteutuu voimakkuudeltaan yleisesti käytettyjen malliversioiden mukaisena. Pohjanlahden pohjoisosassa Perämerellä jäätalvien keskimääräinen kesto sen sijaan mahdollistaa todennäköisesti itämerennorpan pesinnän myös vuosina 2071–2100. Perämerelläkin jäätalvet kuitenkin heikkenevät tulevaisuudessa. Väitöskirjan toisessa osatyössä tutkittiin norpan esiintymishistoriaa Itämerellä. Norpat ovat eläneet merellä jo varhain. Ensimmäiset ajoitetut löydöt Itämeren sisäosista ovat Suomen puolelta Pohjanlahtea ja yli 10 000 vuoden ikäisiä. Norpat ovat todennäköisesti eläneet Itämerellä tästä lähtien suhteellisen yhtäjaksoisesti, ja siten myös niin sanotun holoseenin lämpökauden aikana. Tällöin talvien lämpötila ei kuitenkaan ollut todennäköisesti niin korkea kuin se ilmastomallien mukaan tulee todennäköisesti olemaan tämän vuosisadan lopulla. Kolmannen osatyön mukaan lämpötilan vuotuinen vaihtelu muuttoreitillä satojen ja jopa yli tuhannen kilometrin päässä vaikuttaa lintujen Suomeen saapumisen ajoitukseen. Linnut saapuvat keskimäärin tavallista aikaisemmin, kun kevät on muuttoreitillä tavallista lämpimämpi. Lämpötila muuttoreitillä vaihtelee noin tuhannen kilometrin etäisyydelle asti samansuuntaisesti kuin Suomessa. Linnut pystyvät siten mahdollisesti joissain tapauksessa sopeuttamaan muuttoaikatauluaan niin, että saapuminen pesimäalueelle mukailee kevään etenemisen vuosien välistä vaihtelua. Väitöskirjan neljännessä osatyössä osoitetaan lämpötilan ja sadannan vaikuttavan yleisen hyönteisen, sylkikaskaan populaatiokokoon Hangossa Tvärminnen eläintieteellisellä asemalla sijaitsevilla tutkimussaarilla. Laajasti Euroopan ilmaston vaihteluun jaksollisesti vaikuttava Pohjois-Atlantin värähtely (NAO) vaikutti sylkikaskaan populaatiokokoihin. NAO:n vaihtelua mitataan erityisellä indeksillä. Kun se oli talvella positiivinen, talvet ja alkukeväät olivat lämpimiä, ja kaskaiden määrä tyypillisesti väheni. Yhteys kaskaisiin välittyi todennäköisesti ainakin toukkakuolleisuuden kautta, ja mahdollisesti myös talven NAO:n vaikuttaessa viipeellä myös kevään lämpötiloihin. Väitöskirjan kaikilla tutkimuslajeilla on elinkierrossaan herkkiä vaiheita: norpalla jääelinympäristö, muuttolinnuilla muuton tarkka ajoitus, sylkikaskailla kuivumiselle herkkä aika, jonka toukka on sylkimäisen vaahtomuodostuman suojaamana. Lajien elämänkierron tämän tyyppisten heikkouskohtien tutkimus voi auttaa niiden suojelussa. Esimerkiksi itämerennorpan suojelussa on myös selvää, että ilmastonmuutoksen hillinnän ohella on syytä vähentää muita itämerennorpan menestymistä haittaavia tekijöitä, sillä laji on nyt saanut ilmastonmuutoksesta uuden rasitustekijän

The Variance in Genetic Diversity Among Subpopulations is More Sensitive to Founder Effects and Bottlenecks Than is the Mean: A Case Study

Wetensch. publicati

Comparative cytogenetics of Auchenorrhyncha (Hemiptera, Homoptera): a review

A comprehensive review of cytogenetic features is provided for the large hemipteran suborder Auche norrhyncha, which currently contains approximately 42,000 valid species. This review is based on the analysis of 819 species, 483 genera, and 31 families representing all presently recognized Auchenorrhyn cha superfamilies, e.i. Cicadoidea (cicadas), Cercopoidea (spittle bugs), Membracoidea (leafhoppers and treehoppers), Myerslopioidea (ground-dwelling leafhoppers), and Fulgoroidea (planthoppers). History and present status of chromosome studies are described, as well as the structure of chromosomes, chro mosome counts, trends and mechanisms of evolution of karyotypes and sex determining systems, their variation at different taxonomic levels and most characteristic (modal) states, occurrence of partheno genesis, polyploidy, B-chromosomes and chromosome rearrangements, and methods used for cytoge netic analysis of Auchenorrhyncha.info:eu-repo/semantics/publishedVersio

Population structure, adaptation and divergence of the meadow spittlebug, Philaenus spumarius (Hemiptera, Aphrophoridae), revealed by genomic and morphological data

Understanding patterns of population differentiation and gene flow in insect vectors of plant diseases is crucial for the implementation of management programs of disease. We investigated morphological and genome-wide variation across the distribution range of the spittlebug Philaenus spumarius (Linnaeus, 1758) (Hemiptera, Auchenorrhyncha, Aphrophoridae), presently the most important vector of the plant pathogenic bacterium Xylella fastidiosa Wells et al., 1987 in Europe. We found genome-wide divergence between P. spumarius and a very closely related species, P. tesselatus Melichar, 1899, at RAD sequencing markers. The two species may be identified by the morphology of male genitalia but are not differentiated at mitochondrial COI, making DNA barcoding with this gene ineffective. This highlights the importance of using integrative approaches in taxonomy. We detected admixture between P. tesselatus from Morocco and P. spumarius from the Iberian Peninsula, suggesting gene-flow between them. Within P. spumarius, we found a pattern of isolation-by-distance in European populations, likely acting alongside other factors restricting gene flow. Varying levels of co-occurrence of different lineages, showing heterogeneous levels of admixture, suggest other isolation mechanisms. The transatlantic populations of North America and Azores were genetically closer to the British population analyzed here, suggesting an origin from North-Western Europe, as already detected with mitochondrial DNA. Nevertheless, these may have been produced through different colonization events. We detected SNPs with signatures of positive selection associated with environmental variables, especially related to extremes and range variation in temperature and precipitation. The population genomics approach provided new insights into the patterns of divergence, gene flow and adaptation in these spittlebugs and led to several hypotheses that require further local investigation.Peer reviewe

Meiotic chromosomes and nucleolar behavior in testicular cells of the grassland spittlebugs Deois flavopicta, Mahanarva fimbriolata and Notozulia entreriana (Hemiptera, Auchenorrhyncha)

Spittlebugs annually infest pastures and cause severe damage, representing a serious problem for the tropical American beef cattle industry. Spittlebugs are an important biotic constraint to forage production and there is a lack of cytogenetic data for this group of insects. For these reasons, we conducted this work, in which the spermatogenesis and nucleolar behavior of Deois flavopicta, Mahanarva fimbriolata and Notozulia entreriana were studied. The males possessed testes in the shape of a “bunch of grapes”; a variable number of testicular lobes per individual and polyploid nuclei composed of several heteropycnotic bodies. A heteropycnotic area was located in the periphery of the nucleus (prophase I); the chiasmata were terminal or interstitial; metaphases I were circular or linear and anaphase showed late migration of the sex chromosome. The chromosome complement had 2n = 19, except for N. entreriana (2n = 15); the spermatids were round with heteropycnotic material in the center and elongated with conspicuos chromatin. The analysis of testes after silver nitrate staining showed polyploid nuclei with three large and three smaller nucleolar bodies. Early prophase cells had an intensely stained nucleolar body located close to the chromatin and another less evident body located away from the chromatin. The nucleolar bodies disintegrated during diplotene. Silver staining occurred in two autosomes, in terminal and subterminal locations, the latter probably corresponding to the nucleolus organizer regions (NORs). The spermatids were round with a round nucleolar body and silver staining was observed in the medial and posterior region of the elongated part of the spermatid head