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The relevance of the study. Apple sawfly (Hoplocampa testudinea Klug), black plum (Hoplocampa minuta Christ.) and yellow plum (Hoplocampa flava L.) sawflies (Hymenoptera, Symphyta, Tenthredinidae) are serious and widespread pests of apple and plum fruits. Dock sawfly (Ametastegia glabrata Fall.) is a non-specialized apple pest and its larvae feed generally on leaves of Chenopodium sp. and Polygonum sp.; however, occasionally mature fruits at harvest are found damaged by larvae of this insect. Former studies indicated that these species caused significant damage to apple and plum yield in Lithuania in mid-late XX century. However, at that time the setup of apple and plum genotypes cultivated was completely different from conventional orchard management techniques and cultivars at present time. Therefore, the growing diversity of cultivated fruit-tree genotypes leaves gaps in knowledge as to how apple and plum sawflies will affect some of the newer cultivars. In Lithuania, no data on susceptibility of economically important apple and plum cultivars to sawfly damage in commercial orchards is available. A shift towards integrated pest management and development of organic fruit farming poses new challenges to apple growers and plant protection specialists. According to the requirements of these management strategies, the use of synthetic pesticides must be reduced or is not allowed at all. Several reports from countries where the use of synthetic insecticides was significantly... [to full text] / Temos aktualumas. Obuolinis pjūklelis (Hoplocampa testudinea Klug), slyvinis juodasis (Hoplocampa minuta Christ.) ir slyvinis geltonasis (Hoplocampa flava L.) pjūkleliai, priklausantys plėviasparnių (Hymenoptera) būriui, tikrųjų pjūklelių (Tenthredinidae) šeimai, yra reikšmingi specializuoti obelų ir slyvų vaisių kenkėjai, paplitę viso pasaulio obelų ir slyvų auginimo regionuose (Velbinger, 1939; Alford, 2007; Vincent, Belair, 1992). Rūgtinis pjūklelis (Ametastegia glabrata Fall.) priklauso tai pačiai šeimai – ir, nors jo lervos pagrindinai minta balandinių ir rūgtinių augalų lapais, tačiau dažnai aptinkama ir šio vabzdžio lervų pažeistų obuolių. Anksčiau Lietuvoje obuolinis bei slyviniai pjūkleliai būdavo žalingi senesniuose soduose. Susidarius palankioms sąlygoms masiškai plisti arba vaismedžiams derant negausiai, šių kenkėjų daroma žala viršydavo kitų pagrindinių obelų ir slyvų kenkėjų, tokių kaip obuolinis (Cydia pomonella L.) ar slyvinis (Grapholita funebrana Treits) vaisėdžiai, daromą žalą. Pavyzdžiui, slyviniai pjūkleliai susidarius palankioms sąlygoms – šiltam ir ankstyvam pavasariui, sunaikindavo daugiau kaip 60% kai kurių veislių slyvų vaisių derliaus (Заянчкаускас, 1958). Per paskutinius du dešimtmečius Lietuvoje senuosius sodus pakeitė intensyvūs ir ekologiniai sodai, kuriuose sodinami naujų veislių vaismedžiai su žemaūgiais poskiepiais. Pasikeitus ūkininkavimo sąlygoms, keičiantis aplinkos sąlygoms, šylant klimatui, keičiasi kenkėjų rūšinė sudėtis bei žalingumas... [toliau žr. visą tekstą]

Stereochemistry plays an important role in nature because biologically important molecules such as amino acids, nucleotides and sugars, only exist in enantiomerically pure forms. Semiochemicals carry messages, between the same species (pheromones) and between different species (allelochemicals). Both pheromones and allelochemicals can be used as environmentally friendly pest management. Many semiochemicals, i.e. behaviour modifying chemicals, consist of pure or well-defined mixtures of stereoisomers, where some of the other stereoisomers can be repellent. It is therefore important to be able to separate them to produce a synthetic pheromone in a mixture that is attractive. Pine sawflies are a family of insects that in some cases can be severe defoliators of conifer trees. Diprion pini, Diprion similis and Neodiprion sertifer are severe pests for these trees and have got the most attention in pine sawfly pheromone studies. The pheromone precursors are stored in the female body as long-chain secondary alcohols, which, when released, are esterified to acetates or propionates. The alcohols are chiral, and normally one of the stereoisomer is the main pheromone component, sometimes possible together with other stereoisomers as essential minor components. Bicyclus is a genus of African butterflies, and especially Bicyclus anynana has become a popular model for the study of life history evolution, morphology, mating choice and genetics. The wing pattern of Bicyclus differs depending on the season, with large eyespots during the rain-season and small or absent spots during the dry season.  Euglossa is one of the genera among the orchid bees in the Neotropics that does not produce its own pheromone. Instead, the males collect fragrances from orchids and other sources and store them in a pocket in their hind legs. Both Bicyclus and Euglossa use semiochemicals similar to pine sawflies, and thus can be analysed by the same methods. Pheromones and other semiochemicals in insects are often present in low amounts in a complex matrix, and purification of the sample before chemical analysis is often required. A common method is gradient elution on a solid phase silica column. Separation of stereoisomers can be achieved either by using a column with a chiral stationary phase (CSP) or with pre-column derivatisation using a column with an achiral stationary phase (ASP) or a combination of both, with mass detection as the dominant detection method. The purpose of this work has been to improve the purification method, find suitable methods to separate the stereoisomers of secondary alcohols, and to apply this on extracts of insects. By selecting the right fractions to collect during gradient elution the purification method was optimised. To reduce plasticizer contamination from ordinary columns, solid phase columns of Teflon or glass were used. For pre-column derivatisation of different chiral alcohols various acid chlorides were tested. For the pine sawfly pheromone precursors enantiopure (2S)-2-acetoxypropionyl chloride was the best choice. To separate some of the stereoisomers achiral 2-naphthoyl chloride was used. For derivatisation of 6,10,14-trimethylpentadecan-2-ol (R)-trans-chrysanthemoyl chloride was the best choice. The derivatised alcohols were separated on different columns, both chiral and non-chiral. Varian FactorFour VF-23ms was chosen as a general-purpose column, the Agilent HP-88 column was the best column with an ASP of those tested, and the Chiraldex B-PA column (CSP) was the only one that could separate all eight stereoisomers of derivatised 3,7-dimethylundecan-2-ol, 3,7-dimethyldodecan-2-ol, and 3,7-dimethyltridecan-2-ol. To determine the stereoisomeric purity of standard solutions used in field experiments and extracts of different species of insects the optimised methods were applied. For extracts from B. anynana, Euglossa and Neodiprion lecontei this work describe the first determination of the stereochemistry of some of their semiochemicals. For the determination of the stereochemistry of chiral semiochemicals the methods for purification and separation presented herein have shown to be of great value. The results will hopefully contribute to a better understanding of the communication among insects, and ultimately to a more environmentally friendly pest control. / Många naturligt förekommande kemiska ämnen finns som två spegelbilder av varandra, ungefär som höger och vänster hand. Dessa kan ha helt olika egenskaper och det är därför viktigt att kunna separera dem. Insekter och andra djur använder olika doftämnen för att kommunicera med varandra, om det är inom samma art kallas de för feromoner. De kan bestå av ett ämne eller en blandning av flera. Dessa doftämnen kan man även använda för att på ett miljövänligt sätt bekämpa skadeinsekter. En fälla med syntetiskt feromon för en viss insekt lockar endast till sig den arten, medan alla andra är opåverkade. Eftersom dessa ämnen ofta finns som spegelbilder där kanske bara den ena är aktiv och den andra rent av frånstötande, måste man kunna separera dem för att framställa ett syntetiskt feromon som är attraktivt. Målet med detta arbete har varit att bestämma feromonet hos olika arter av tallsteklar som kan vara svåra skadedjur på tallskog. De metoder som tagits fram har även tillämpats på några arter av afrikanska fjärilar samt orkidébin från Centralamerika eftersom de använder snarlika doftämnen. Att få fram feromonet från en insekt är lite som att leta efter in nål i en höstack eftersom de ofta bara innehåller några miljarddels gram per individ. Provet behöver först renas, och en del av arbetet i det här projektet har gått ut på att ta fram en lämplig reningsmetod. Huvudfokus har dock varit på att ta fram metoder som kan separera och identifiera det eller de ämnen, och spegelbilder av dessa, som doftämnena består av. När lämpliga metoder tagits fram har extrakt av olika insektsarter analyserats. I några fall är det första gången som deras feromon bestämts i detalj. Resultaten kan förhoppningsvis bidra till en ökad kunskap om insekters sätt att kommunicera, och i slutändan till miljövänligare bekämpning av skadeinsekter.

Phytophagous insects make up over one quarter of described species on Earth, and this incredible diversity seems directly linked to feeding on plants. Comparative studies of sister groups have shown shifts to herbivory are consistently associated with increased species diversity in insects, but the reasons for this diversification remain unclear. While other explanations, such as decreased extinction rates or influences on population structure, exist, one prominent hypothesis suggests shifts and subsequent adaptation to novel host plants can lead to the evolution of reproductive barriers. Given their extreme specialization on host plants in the genus Pinus and intimate, life-long association with their host plants, divergent host use has been suspected to drive speciation in the conifer sawfly genus Neodiprion. Previous work showed host shifts coincide with speciation events in the genus; but could not determine if these host shifts initiated speciation or if they occurred after other reproductive barriers arose. Determining the contribution and timing of host shifts relative to speciation will require examination of populations at the earliest stages of divergence, before post-speciation changes amass. If host shifts frequently drive speciation in the genus, there will likely be evidence of host-driven divergence within species occurring on a wide range of host plants. The goal of this dissertation is to examine populations of the red-headed pine sawfly, Neodiprion lecontei, an abundant, well-studied pest species that occurs on multiple hosts throughout its range, for evidence of host-driven divergence. Using a combination of reduced representation genomic sequencing, population genomics, and ecological assays, I specifically look for evidence of 1) genetic differentiation between populations utilizing different host plants, 2) ecological divergence in female oviposition preference, larval performance, and ovipositor morphology between populations on different hosts, and 3) ecologically-driven reproductive isolation between genetically and ecologically divergent populations. Each chapter of this dissertation examines the role of host use in driving ecological, genetic, and/or reproductive divergence within N. lecontei at a different spatial scale. First, I surveyed range-wide patterns of diversity. I identified three genetic clusters, dated the divergence of these clusters to the late Pleistocene, and found evidence that both dispersal limitation (geography) and host use contribute to genetic differentiation within N. lecontei. Next, I looked within one of these genetic clusters for additional evidence of the role of host in driving divergence. Sawflies in this cluster primarily utilize two hosts which differ significantly in needle architecture. Although I found no evidence of neutral genetic differentiation between hosts exists, I did detect spatial and temporal differences in host use, and host-specific differences in ovipositor morphology, a performance-related trait. Finally, I examine a single site where N. lecontei utilizes three structurally divergent species of pine. Although there was little genetic structure, no sexual isolation, and no distinct host preferences, the host types were partially temporally isolated and varied in ovipositor morphology and larval performance across on the three hosts. Overall, although divergent host use consistently resulted in divergent ovipositor morphology, a reduction in gene flow via temporal or geographic isolation may be required before additional forms of ecological and genetic differentiation can develop. Together these results suggest host shifts alone may not be enough to drive population divergence and speciation in Neodiprion.