Wolbachia (Alphaproteobacteria) is an inherited endosymbiont of arthropods and filarial nematodes and was reported to be widespread across insect taxa. While Wolbachia’s effects on host biology are not understood from most of these hosts, known Wolbachia-induced phenotypes cover a spectrum from obligate beneficial mutualism to reproductive manipulations and pathogenicity. Interestingly, data on Wolbachia within the most species-rich order of arthropods, the Coleoptera (beetles), are scarce. Therefore, we screened 128 species from seven beetle families (Buprestidae, Hydraenidae, Dytiscidae, Hydrophilidae, Gyrinidae, Haliplidae, and Noteridae) for the presence of Wolbachia. Our data show that, contrary to previous estimations, Wolbachia frequencies in beetles (31% overall) are comparable to the ones in other insects. In addition, we used Wolbachia MLST data and host phylogeny to explore the evolutionary history of Wolbachia strains from Hydraenidae, an aquatic lineage of beetles. Our data suggest that Wolbachia from Hydraenidae might be largely host genus specific and that Wolbachia strain phylogeny is not independent to that of its hosts. As this contrasts with most terrestrial Wolbachia–arthropod systems, one potential conclusion is that aquatic lifestyle of hosts may result in Wolbachia distribution patterns distinct from those of terrestrial hosts. Our data thus provide both insights into Wolbachia distribution among beetles in general and a first glimpse of Wolbachia distribution patterns among aquatic host lineages.

Wolbachia (Alphaproteobacteria) is an inherited endosymbiont of arthropods and filarial nematodes and was reported to be widespread across insect taxa. While Wolbachia’s effects on host biology are not understood from most of these hosts, known Wolbachia-induced phenotypes cover a spectrum from obligate beneficial mutualism to reproductive manipulations and pathogenicity. Interestingly, data on Wolbachia within the most species-rich order of arthropods, the Coleoptera (beetles), are scarce. Therefore, we screened 128 species from seven beetle families (Buprestidae, Hydraenidae, Dytiscidae, Hydrophilidae, Gyrinidae, Haliplidae, and Noteridae) for the presence of Wolbachia. Our data show that, contrary to previous estimations, Wolbachia frequencies in beetles (31% overall) are comparable to the ones in other insects. In addition, we used Wolbachia MLST data and host phylogeny to explore the evolutionary history of Wolbachia strains from Hydraenidae, an aquatic lineage of beetles. Our data suggest that Wolbachia from Hydraenidae might be largely host genus specific and that Wolbachia strain phylogeny is not independent to that of its hosts. As this contrasts with most terrestrial Wolbachia–arthropod systems, one potential conclusion is that aquatic lifestyle of hosts may result in Wolbachia distribution patterns distinct from those of terrestrial hosts. Our data thus provide both insights into Wolbachia distribution among beetles in general and a first glimpse of Wolbachia distribution patterns among aquatic host lineages.

Dytiscidae, contains numerous endemic and non-endemic species on Madagascar. Their evolutionary history is largely unknown on the island. Herein, I use analyses to infer phylogenetic relationship among groups of diving beetles, with a focus on the subfamily Dytiscinae and endemic species in two other groups of Dytiscidae. Paper I represents the first phylogenetic reconstruction focusing on the tribe Aciliini based on molecular data. Several commonly used molecular markers, as well as a new marker for Hydradephagan beetles, were evaluated in this study. Our analyses suggest that six genera within Aciliini are monophyletic. The most basal clades with Neotropical and Afrotropical taxa suggest a possible Gondwanan origin. Evaluation of gene fragments indicated CAD to be the most informative marker. Paper II focuses on colonization and radiation events of large bodied endemic diving beetles of the tribes Cybistrini and Hydaticini on Madagascar. Colonization events were inferred from dated phylogenetic trees and ancestral biogeographical reconstructions. Our results suggest both multiple colonizations, and out-of-Madagascar dispersal events, mostly during the Miocene and Oligocene. In paper III, we revised the Rhantus species of Madagascar. We used both molecular and morphological data to evaluate species hypothesis and emphasized the value of Manjakatompo – one of the last remaining fragments of central highland forests. In Paper IV we reconstruct the phylogeny and use Species Distribution Modelling for the endemic genus Pachynectes in Madagascar. Our sampling has discovered that the species diversity of Pachynectes is at least three times higher than previously believed. It seems that allopatric speciation was the main driver, which led to the diversity of Pachynectes. Our results suggest that climatic gradients and the five main biomes were a better predictor than watershed systems in explaining the distribution pattern and speciation between sister species. / Dykarskalbaggar i familjen Dytiscidae finns över hela världen och kan hittas i såväl temporära som permanenta vattensamlingar, i rinnande såväl som i stillastående akvatiska habitat. Bland dykarskalbaggarna finns ett hundratal både endemiska och icke-endemiska arter på Madagaskar. Deras evolutionära historia på denna mytomspunna ö är dock i stort sett okänd. I den här avhandlingen använder jag molekylära data och analyser för att härleda evolutionära släktskap, s.k. fylogenier eller släktträd, för olika grupper av dykarskalbaggar med fokus på underfamiljen Dytiscinae samt endemiska arter från två andra grupper på Madagaskar. Artikel 1 är den första molekylär-fylogenetiska studien som gjort på tribuset Aciliini. Flera molekylära markörer (delar av gener) användes samt utvärderades, inklusive den nya markören CAD för Hydradephaga skalbaggar. Analysen bekräftar att tribuset Aciliini är en monofyletisk grupp (naturlig grupp som härstammar från en gemensam förfader) samt att Eretini är närmaste släktingen. Alla sex släkten med flera arter i tribuset stöddes också som monofyletiska, det sjunde släktet har bara en art. De mest basala grupperna i trädet utgjordes av Neotropiska och Afrotropiska arter vilket antyder ett ursprung på Gondwana kontinenten. Denna slutsats var dock beroende av för vilken nod i trädet (av två möjliga) som ett fossil användes som kalibreringspunkt. Utvärderingen av de olika genfragmenten ledde till slutsatsen att CAD var den mest informativa genen tätt följd av en annan nukleär proteinkodande gen, WNT. Artikel 2 fokuserar på kolonisations- och artbildningshändelser för två grupper av relativt stora dykarskalbaggar. Denna studie bygger på två tidigare publicerade dataset där vi lade till Madagaskars arter. Kolonisationshändelser härleddes genom daterade molekylära släktträd samt rekonstruktion av förfäders biogeografiska utbredningsområden. Resultaten visade både på ett flertal separata koloniseringshändelser men också "ut-ur-Madagaskar" spridning, framförallt under tidsperioden Miocen-Oligocen. Studien visade också att inga koloniseringshändelser lett till några signifikanta artradiationer på Madagaskar i dessa två grupper. I Artikel 3 reviderar vi arterna av släktet Rhantus som finns på Madagaskar, vilka alla är begränsade i sin utbredning till den centrala högplatån på Madagaskar. Vi använder både morfologi och molekylära data för att testa arthypoteser samt bestyrker det bevarandebiologiska värdet av Manjakatompo-skogen, ett av de allra sista fragmenten av skog på den centrala högplatån. I Artikel 4 härleder vi släktskapet för det endemiska rinnande-vatten släktet Pachynectes samt analyserar de ingående arternas utbredning genom modellering. Våra insamlingar runt om Madagaskar har visat att artdiversiteten i släktet är minst tre gånger så hög som man tidigare trott. Genom att integrera släktskapsanalys med utbredningsmodellering söker vi få en inblick i vad som drivit artbildningen i en endemisk artradiation. Allopatrisk artbildning verkar varit den huvudsakliga typen av artbildning inom Pachynectes. Vi testade även två huvudhypoteser som söker förklara mikroendemisk artbildning generellt på Madagaskar. Våra resultat visar att klimatgradienter och de fem huvudsakliga biomen på Madagaskar verkar ha en långt bättre förklaringsgrad än stora floder och avrinningsområden för att förklara Pachynectes arternas utbredning och släktskap. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.</p>

Diss. (sammanfattning) Linköping : Univ., 2003. / Härtill 5 uppsatser.

I studied the influence of fishpond management and environmental characteristics on diving beetles (Coleoptera: Dytiscidae), which are important predators in aquatic systems. In 2014 I used live traps to study diving beetle communities in 117 ponds in South Bohemia. The ponds were divided in three categories: intensively managed, extensively managed, and without fish. In total 26 species of diving beetles were found (N=1346). Overall, the beetles prefered shallow litoral zones with cattail (Typha), manna grass (Glyceria) and reed (Phragmites). The number of species declined with increasing alttitude and depth near the trap, while their abundance increased with pond area and amount of detritus near the trap. Beetles occured more in ponds with lower pH, lower conductivity and higher oxygen content. More beetles were found in fishless ponds. On the other hand, some ponds with high density of fishes but well preserved littoral zone had similar communities of diving beetles to the fishless ponds. This shows that high density of fish in ponds decreases the diversity and abundance of diving beetles, most likely because it decreases the vegetation in littoral zone. During the survey, four new localities of Graphoderus bilineatus were found; the species is protected by NATURA 2000 and has been known from very few recent localities in the Třeboň area.

<p>Sexual conflict can lead to antagonistic coevolution between the sexes, but empirical examples are few. In this thesis secondary sexual characters in diving beetles are interpreted in the light of sexual conflict theory. Whether the male tarsal suction cups and female dorsal modifications are involved in a coevolutionary arms race is tested in two ways. First eight populations of a species with dimorphic females that varied in frequency of the morphs were investigated and male tarsal characteristics quantified. The frequency of female morphs is shown to be significantly correlated to the average number and size of male tarsal suction cups in the population, a prediction of the arms race hypothesis. Second, the hypothesis is tested in a phylogenetic perspective by optimizing the secondary sexual characters on a phylogeny. A full taxonomic revision of the genus <i>Acilius</i> is presented, including new synonyms, lectotype designations, geographic distributions based on more than five thousand examined museum specimens and the description of a new species from northeastern USA. Specimens of all species (except one possibly extinct that failed to be found in Yunnan, China 2000), were field collected between 2000 and 2003 in Sardinia, Sweden, Russia, Honshu and Hokkaido in Japan, New York, Maryland, California and Alberta. Three genes (CO1, H3 and Wingless) were sequenced from the fresh material as well as scoring a morphological character matrix all of which was used to derive a robust and complete hypothesis of the phylogenetic relationship in the group. The phylogeny was derived using Bayesian phylogenetics with Markov Chain Monte Carlo techniques and received a posterior probability of 0.85. Changes in male and female characters turned out to be perfectly correlated across the phylogeny, providing one of the best empirical examples to date of an antagonistic arms race between the sexes in a group of organisms. Finally, a review of a pitfall to phylogenetic analysis known under the name long-branch attraction (LBA), is provided. The problem is well known theoretically but has been questioned to occur in real data, and LBA has been in the core center of the hard debate between parsimony and likelihood advocates since different inference methods vary in sensitivity to the phenomenon. Most important conclusions from the review are; LBA is very common in real data, and is most often introduced with the inclusion of outgroups that almost always provide long branches, pulling down long terminal ingroup branches towards the root. Therefore it is recommended to always run analyses with and without outgroups. Taxon sampling is very important to avoid the pitfall as well as including different kind of data, especially morphological data, i.e. many LBA-affected conclusions have recently been reached by analyses of few taxa with complete genomes. Long-branch extraction (incl. outgroup exclusion), methodological disconcordance (parsimony vs modelbased), separate partition analyses (morphology vs molecules, codon positions, genes, etc), parametric simulation (incl. random outgroups), and split graphs are available relevant methods for the detection of LBA that should be used in combinations, because none alone is enough to stipulate LBA.</p>

Sexual conflict can lead to antagonistic coevolution between the sexes, but empirical examples are few. In this thesis secondary sexual characters in diving beetles are interpreted in the light of sexual conflict theory. Whether the male tarsal suction cups and female dorsal modifications are involved in a coevolutionary arms race is tested in two ways. First eight populations of a species with dimorphic females that varied in frequency of the morphs were investigated and male tarsal characteristics quantified. The frequency of female morphs is shown to be significantly correlated to the average number and size of male tarsal suction cups in the population, a prediction of the arms race hypothesis. Second, the hypothesis is tested in a phylogenetic perspective by optimizing the secondary sexual characters on a phylogeny. A full taxonomic revision of the genus Acilius is presented, including new synonyms, lectotype designations, geographic distributions based on more than five thousand examined museum specimens and the description of a new species from northeastern USA. Specimens of all species (except one possibly extinct that failed to be found in Yunnan, China 2000), were field collected between 2000 and 2003 in Sardinia, Sweden, Russia, Honshu and Hokkaido in Japan, New York, Maryland, California and Alberta. Three genes (CO1, H3 and Wingless) were sequenced from the fresh material as well as scoring a morphological character matrix all of which was used to derive a robust and complete hypothesis of the phylogenetic relationship in the group. The phylogeny was derived using Bayesian phylogenetics with Markov Chain Monte Carlo techniques and received a posterior probability of 0.85. Changes in male and female characters turned out to be perfectly correlated across the phylogeny, providing one of the best empirical examples to date of an antagonistic arms race between the sexes in a group of organisms. Finally, a review of a pitfall to phylogenetic analysis known under the name long-branch attraction (LBA), is provided. The problem is well known theoretically but has been questioned to occur in real data, and LBA has been in the core center of the hard debate between parsimony and likelihood advocates since different inference methods vary in sensitivity to the phenomenon. Most important conclusions from the review are; LBA is very common in real data, and is most often introduced with the inclusion of outgroups that almost always provide long branches, pulling down long terminal ingroup branches towards the root. Therefore it is recommended to always run analyses with and without outgroups. Taxon sampling is very important to avoid the pitfall as well as including different kind of data, especially morphological data, i.e. many LBA-affected conclusions have recently been reached by analyses of few taxa with complete genomes. Long-branch extraction (incl. outgroup exclusion), methodological disconcordance (parsimony vs modelbased), separate partition analyses (morphology vs molecules, codon positions, genes, etc), parametric simulation (incl. random outgroups), and split graphs are available relevant methods for the detection of LBA that should be used in combinations, because none alone is enough to stipulate LBA.