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Doctor of Philosophy / Department of Entomology / Gregory Zolnerowich / The subfamily Tillinae is composed of approximately 700 species with a cosmopolitan distribution. In the New World, the group is composed of 164 species classified in 12 genera. Tillinids are generalist predators of other insects but there is some ecological specificity among related species (i.e. predation on bark and wood-boring beetles). The systematics and biogeography of the subfamily have never been studied. Several genera inhabiting the New World have never been revised, a number of species in the group were described more than 50 years ago, and many of those descriptions were inadequate. Consequently, I present here the first systematic and biogeographic study of the Tillinae in the New World. First, a revision of the New World Tillinae, excluding the species-rich Cymatodera Gray is presented. The diagnosis and redescription of 26 species from 11 of the 12 tillinid genera from the New World are given; a new synonym, keys to genera and species, and distribution maps for all the genera treated here are also given. Collection data for all species examined is presented. A new genus was described based on this work in a separate publication. Second, a phylogenetic analysis based on 91 morphological characters and a molecular phylogenetic study based on the analysis of three loci, 16S rDNA, COI and 28S rDNA, for 89 taxa in 37 genera is presented. Results were compared with previous classifications at the subfamily level. Results are generally consistent, recovering Tillinae as a derived and monophyletic group; Old World tillinids were found to be basal groups and sister to New World Tillinae; the New World genus Onychotillus was found to be sister to remaining New World Tillinae; the small genera Barrotillus, Callotillus, Monophylla and Neocallotillus were recovered as basal lineages within the New World Tillinae with intergeneric relations not fully resolved; and the species-rich Cymatodera was found to be a paraphyletic group by the inclusion of the genera Araeodontia, Bogcia, Cymatoderella and Lecontella. A phylogeny was also constructed based on a concatenated molecular + morphology dataset; the topology obtained from this analysis is generally consistent with the molecular- and morphology-based phylogenies, separately. Finally, a hypothesis of the historical biogeography of Cymatodera, the most species-rich genus in the subfamily Tillinae, is presented. The genus is endemic to, but broadly distributed, in the New World. The principal aim of the study was to infer the age of origin of the group. Hypotheses regarding the center of origin, patterns of distribution, and putative processes that led to the widespread distribution of this group are presented. A phylogenetic analysis of 50 New World tillinid species was constructed using the markers 16S rDNA, COI, and 28S rDNA. A relaxed molecular clock calibrated with three secondary dates derived from other time-calibrated phylogenies is presented. Biogeographic processes were studied using a Bayesian Binary Markov Chain Monte Carlo analysis in the software Reconstruct Ancestral State in Phylogenies. Results obtained here indicate that Cymatodera emerged approximately 71.5 MYA during the mid-Cretaceous in what is now southwestern USA and northern Mexico. Two major dispersal events occurred during the evolution of the Cymatodera lineage, the first, an eastern migration process, and the second, a southern migration event, the latter route had a greater impact on the diversification of the group. Overall, this research provides a solid foundation for studying the systematics and biogeography of the world Tillinae. Species with recent shared ancestry tend to have similar functional traits for exploiting similar resources. A robust phylogenetic analysis can help elucidate prey preferences or other biological traits for species whose biology is poorly known. This study will also serve as a foundation to investigate broader evolutionary aspects of the subfamily, such as predator-prey associations, mimicry, and the emergence and diversification of pheromone reception, one of the most interesting aspects within the evolutionary history of the group.

Polyphagy is a very common trait among insects. In this study, we focus on a generalist bark-beetle predator, Thanasimus formicarius (L.) (Coleoptera, Cleridae), which feeds on many scolytids in spruce, pine and broad-leaf stands. It is known to respond to the pheromones of many scolytids, among which the most harmful spruce bark beetle in Europe, Ips typographus (L.). The adults attack scolytid adults and oviposit on attacked trees where their larvae feed upon immature stages of the prey. However, a bottom-up process limits Thanasimus formicarius’ impact on spruce bark beetles, because in most cases the bark of spruce is too thin for sheltering pupal niches and mature larvae have to leave the trees. On pine however, pupation is quite successful and reproductive success is high. The present work estimates the advantages (complementary prey during gaps among the phenology of pine bark beetles or due to the population fluctuations of most scolytids) and constraints (landing on unsuitable host trees for the predator’s reproduction) for T. formicarius to have a wide range of prey. Passive barrier-trappings showed that the presence and abundance of scolytid species vary strongly from year to year. So, polyphagy in T. formicarius appears as a response to fluctuating prey supplies. This way of foraging may lead T. formicarius towards stands not always favourable for its development (for example, spruces). At the tree level, funnels and pitfall-traps caught high numbers of third-instar T. formicarius larvae walking on the bark surface of standing spruces infested by Ips typographus (respectively 365 and 70 L3s). After feeding into the whole infested part of the trunk, these larvae are obliged to migrate outside of the galleries to favourable pupation site (e.g. the base of the trees where the bark is thicker), or even to leave the trees and search for an acceptable pupation substrate in the litter. At the landscape level, different trapping experiments showed a correlation between catches of T. formicarius and the proportion of pines around each trap. Consequently, in a metapopulation landscape pattern, pines would act as “sources” of predators, whilst spruces are “sinks”. Indeed, Thanasimus formicarius are trapped in higher numbers in mixed stands comprising pines. This observation is also corroborated in a four-year trapping experiment in the North-East of France, following the storms of December 1999. The predator/prey ratios (T. formicarius/I. typographus) were higher in stands comprising pines than in stands without pines. The first step of a method to estimate Ips typographus infestation trends thanks to the predator/prey ratios was also developed.

Necrophilous insects, if correctly identified, can provide useful forensic information. Research in this area has focussed on flies and beetles remain comparatively under-studied, partly because some adult carrion beetles are difficult to identify morphologically, as are their juvenile stages, often requiring specialist expertise in both cases. Molecular taxonomy has been proposed as a solution to these problems. DNA “barcodes" are short fragments of mitochondrial cytochrome oxidase I (COI) DNA that are anticipated to delineate species. This approach is becoming increasingly popular, but has been met with varying enthusiasm from taxonomists. This thesis examines their use in identifying forensically significant beetles.The DNA barcodes of 234 specimens of 25 forensically significant southern African beetle species from seven families (Cleridae, Dermestidae, Silphidae, Staphylinidae, Scarabaeidae, Trogidae and Histeridae) were obtained. Thirty-three initial barcode amplification failures were overcome by using primers other than the standard Folmer pair, undermining the barcode concept’s hope of universal primers that would allow even non-specialists to produce barcodes. Another 150 specimens (64%) entirely failed to yield barcodes, including 18 fresh specimens of three species of Trogidae, implying another lack of universality of the barcoding protocol. The majority of the beetles clustered with confamilials on neighbour-joining and maximum likelihood trees, but 1.3% of the barcodes failed to cluster with their respective families, raising questions concerning the associating power of barcodes. The identification tools of the GenBank and BOLD on-line DNA sequence databases identified 21% of the specimens to the species level, 6% of them correctly. There was evidence of a paralogous sequence in the Cleridae that, while supporting identification now that it has been associated with a morphological identification, would hamper attempts at identification by clustering or phylogenetic analysis.Distance and haplotype network analyses of the barcodes of six widespread species showed that they are not geographically structured. Barcodes are thus unlikely to be indicators of the region of origin of a species and will not determine whether a corpse has been relocated after death. To assess whether a different mitochondrial DNA fragment might address (some of) these problems, a 2.2 kb fragment extending from the 5’ end of the COI gene to the 3’ end of the Cytochrome Oxidase II (COII) gene was analysed for nine species. It was found that, for Dermestidae, Scarabaeidae and Histeridae, higher degrees of diversity occurred downstreamof the barcode region, but the region of highest diversity in the Cleridae was in the barcode region. Thus, finding a more reliable fragment along the COI-COII region for each family may make robust and guaranteed DNA-based identification of these beetles more likely. The possibility of a forensic specimen being incorrectly or not identified based on its barcode alone exists in about 40% of cases, even with the new barcodes reported here. Forensic science sets a very high bar in assessing the performance of its techniques, and it is concluded that barcodes currently have unsettling failure rates as court-worthy evidence.

Taxonomic changes are made based on checkered beetle (Coleoptera: Cleridae) types of the Natural History Museum, London (BMNH).Lectotypes are designated (and holotypes and paralectotypes recognized) for 44 species of Hydnocerinae, including the type species for Isolemidia, Parmius, Paupris, Allelidea, Blaesiopthalmus and Lemidia, four species of Enoclerus (Clerinae), and 14 species of Cymatodera (Tillinae). Annotations include comments on additional type material, new type locality, previous (type series) locality, and questionable or missing types. Phyllobaenus pallipes(Gorham) and P. rufithorax (Gorham) are synonymized with P. flavifemoratus(Gorham), P. chapini (Wolcott) is synonymized under P. lateralis (Gorham), and P. villosus (Schenkling) is synonymized under P. longus (LeConte), new synonymies. The first molecular phylogeny of the clerid lineage (Coleoptera: Cleridae, Thanerocleridae) is presented and compared with the two most recent phylogenetic hypotheses of the group. Phylogenetic relationships of checkered beetles wareere inferred from approximately 5,000 nucleotides amplified from four loci (28S, 16S, 12S, COI). A worldwide sample of ~70 genera is included and phylogenies are reconstructed using Bayesian Inference and Maximum Likelihood. The results are not entirely congruent with either of the current classification systems. Three major lineages are recognized. Tillinae are supported as the sister group to all other subfamilies, whereas Thaneroclerinae, Korynetinae sensu latu and a new subfamily formally described here, Epiclininae, new subfamily, form a sister group to Clerinae + Hydnocerinae. To assess the phylogeny and evolution of Hemiptera, a comprehensive mitogenomic analysis integrating mitogenome-based molecular phylogenetics, fossil-calibrated divergence dating (using BEAST), and ancestral state reconstructions are presented. The 81 sampled mitogenomes represent the most extensive mitogenomic analyses of Hemiptera to date. The putatively primitive “Homoptera” was previously rendered paraphyletic by Heteroptera, whereas the presented results support each group as monophyletic. The results from both diet and habitat ancestral state reconstructions support that 1) Heteroptera (and Homoptera) evolved from a phytophagous ancestor, contrary to the popular hypothesis that the ancestor was predaceous; and 2) family-level radiation of Heteroptera is coincident with the apically-produced labium and the novel hemelytron. It is here proposed these morphological innovations facilitated multiple independent shifts from phytophagy to predation and multiple independent colonizations of aquatic habitats.

Polyphagy is a very common trait among insects. In this study, we focus on a generalist bark-beetle predator, Thanasimus formicarius (L.) (Coleoptera, Cleridae), which feeds on many scolytids in spruce, pine and broad-leaf stands. It is known to respond to the pheromones of many scolytids, among which the most harmful spruce bark beetle in Europe, Ips typographus (L.). The adults attack scolytid adults and oviposit on attacked trees where their larvae feed upon immature stages of the prey. <p>However, a bottom-up process limits Thanasimus formicarius’ impact on spruce bark beetles, because in most cases the bark of spruce is too thin for sheltering pupal niches and mature larvae have to leave the trees. On pine however, pupation is quite successful and reproductive success is high. <p><p>The present work estimates the advantages (complementary prey during gaps among the phenology of pine bark beetles or due to the population fluctuations of most scolytids) and constraints (landing on unsuitable host trees for the predator’s reproduction) for T. formicarius to have a wide range of prey. <p><p>Passive barrier-trappings showed that the presence and abundance of scolytid species vary strongly from year to year. So, polyphagy in T. formicarius appears as a response to fluctuating prey supplies. <p><p>This way of foraging may lead T. formicarius towards stands not always favourable for its development (for example, spruces). <p>At the tree level, funnels and pitfall-traps caught high numbers of third-instar T. formicarius larvae walking on the bark surface of standing spruces infested by Ips typographus (respectively 365 and 70 L3s). After feeding into the whole infested part of the trunk, these larvae are obliged to migrate outside of the galleries to favourable pupation site (e.g. the base of the trees where the bark is thicker), or even to leave the trees and search for an acceptable pupation substrate in the litter. <p><p>At the landscape level, different trapping experiments showed a correlation between catches of T. formicarius and the proportion of pines around each trap. Consequently, in a metapopulation landscape pattern, pines would act as “sources” of predators, whilst spruces are “sinks”. Indeed, Thanasimus formicarius are trapped in higher numbers in mixed stands comprising pines. This observation is also corroborated in a four-year trapping experiment in the North-East of France, following the storms of December 1999. The predator/prey ratios (T. formicarius/I. typographus) were higher in stands comprising pines than in stands without pines. The first step of a method to estimate Ips typographus infestation trends thanks to the predator/prey ratios was also developed. <p> / Doctorat en sciences, Spécialisation biologie animale / info:eu-repo/semantics/nonPublished