Adaptive divergence and post-zygotic barriers to gene flow between sympatric populations of a herbivorous mite.

Plant-herbivore interactions promote the generation and maintenance of both plant and herbivore biodiversity. The antagonistic interactions between plants and herbivores lead to host race formation: the evolution of herbivore types specializing on different plant species, with restricted gene flow between them. Understanding how ecological specialization promotes host race formation usually depends on artificial approaches, using laboratory experiments on populations associated with agricultural crops.

Draft Genome Assembly of the False Spider Mite .

The false spider mite Brevipalpus yothersi infests a broad host plant range and has become one of the most economically important species within the genus . This phytophagous mite inflicts damage by both feeding on plants and transmitting plant viruses. Here, we report the first draft genome sequence of the false spider mite, which is also the first plant virus mite vector to be sequenced.

The Lesser Antillean Iguana (Iguana delicatissima) on St. Eustatius: Genetically Depauperate and Threatened by Ongoing Hybridization.

The Lesser Antillean Iguana (Iguana delicatissima) is an endangered species threatened by habitat loss and hybridization with non-native Green Iguanas (Iguana iguana). Iguana delicatissima has been extirpated on several islands, and the Green Iguana has invaded most islands with extant populations. Information is essential to protect this species from extinction.

Variability of Bacterial Communities in the Moth Heliothis virescens Indicates Transient Association with the Host.

Microbes associated with insects can confer a wide range of ecologically relevant benefits to their hosts. Since insect-associated bacteria often increase the nutritive value of their hosts' diets, the study of bacterial communities is especially interesting in species that are important agricultural pests. We investigated the composition of bacterial communities in the noctuid moth Heliothis virescens and its variability in relation to developmental stage, diet and population (field and laboratory), using bacterial tag-encoded FLX pyrosequencing of 16S rRNA amplicons.

No adaptation of a herbivore to a novel host but loss of adaptation to its native host.

Most herbivorous arthropods are host specialists and the question is which mechanisms drive the evolution of such specialization. The theory of antagonistic pleiotropy suggests that there is a trade-off between adaptation of herbivores to a novel host and their native host. The mutation accumulation hypothesis proposes that herbivores on a novel host lose their adaptation to the native host through the accumulation of mutations with negligible effects on performance on the novel host.

Incomplete premating and postmating reproductive barriers between two parapatric populations of a social spider mite.

Closely related species with overlapping distributions often show premating reproductive barriers to avoid hybridization. Stigmaeopsis miscanthi (Saito) is a social spider mite infesting Chinese silver grass, and the species consists of two parapatric groups with frequent contacts within the contact zone. They differ in male-male aggressiveness, male morphology, female diapause traits, and life history parameters.

The endosymbionts Wolbachia and Cardinium and their effects in three populations of the predatory mite Neoseiulus paspalivorus.

Whereas endosymbiont-induced incompatibility is known to occur in various arthropod taxa, such as spider mites, insects and isopods, it has been rarely reported in plant-inhabiting predatory mites (Acari: Phytoseiidae). Recent cross-breeding studies with the phytoseiid mite Neoseiulus paspalivorus De Leon revealed a complete post-mating reproductive isolation between specimens collected from three geographic origins-Northeast Brazil (South America), Benin and Ghana (West Africa)-even though they are morphologically similar. We carried out a study to assess to what extent these populations exhibit genetic differences and whether endosymbionts are involved in the incompatibility.

Females as intraguild predators of males in cross-pairing experiments with phytoseiid mites.

Studies on intraguild interactions between phytoseiid species have shown that intraguild predation occurs and is most commonly manifested as adult females of one species feeding on juveniles of another. Whether such intraguild interactions can also occur between adult females of one species and adult males of another, is not known. Herein, we report on intraguild interactions between adults of the two sexes in cross-pairing experiments involving three related phytoseiid species (Neoseiulus paspalivorus, N.

Morphological, molecular and cross-breeding analysis of geographic populations of coconut-mite associated predatory mites identified as Neoseiulus baraki: evidence for cryptic species?

Surveys were conducted in Brazil, Benin and Tanzania to collect predatory mites as candidates for control of the coconut mite Aceria guerreronis Keifer, a serious pest of coconut fruits. At all locations surveyed, one of the most dominant predators on infested coconut fruits was identified as Neoseiulus baraki Athias-Henriot, based on morphological similarity with regard to taxonomically relevant characters. However, scrutiny of our own and published descriptions suggests that consistent morphological differences may exist between the Benin population and those from the other geographic origins.

Diversity and recombination in Wolbachia and Cardinium from Bryobia spider mites.

Background: Wolbachia and Cardinium are endosymbiotic bacteria infecting many arthropods and manipulating host reproduction. Although these bacteria are maternally transmitted, incongruencies between phylogenies of host and parasite suggest an additional role for occasional horizontal transmission. Consistent with this view is the strong evidence for recombination in Wolbachia, although it is less clear to what extent recombination drives diversification within single host species and genera.

How diverse is the genus Wolbachia? Multiple-gene sequencing reveals a putatively new Wolbachia supergroup recovered from spider mites (Acari: Tetranychidae).

At least 20% of all arthropods and some nematode species are infected with intracellular bacteria of the genus Wolbachia. This highly diverse genus has been subdivided into eight "supergroups" (A to H) on the basis of nucleotide sequence data. Here, we report the discovery of a new Wolbachia supergroup recovered from the spider mite species Bryobia species V (Acari: Tetranychidae), based on the sequences of three protein-coding genes (ftsZ, gltA, and groEL) and the 16S rRNA gene.

Origins of asexuality in Bryobia mites (Acari: Tetranychidae).

Background: Obligate asexual reproduction is rare in the animal kingdom. Generally, asexuals are considered evolutionary dead ends that are unable to radiate. The phytophagous mite genus Bryobia contains a large number of asexual species.

Onion thrips, Thrips tabaci, have gut bacteria that are closely related to the symbionts of the western flower thrips, Frankliniella occidentalis.

It has been shown that many insects have Enterobacteriaceae bacteria in their gut system. The western flower thrips, Frankliniella occidentalis Pergande [Thysanoptera: Thripidae], has a symbiotic relation with Erwinia species gut bacteria. To determine if other Thripidae species have similar bacterial symbionts, the onion thrips, Thrips tabaci, was studied because, like F.

Spider mite (Acari: Tetranychidae) mitochondrial COI phylogeny reviewed: host plant relationships, phylogeography, reproductive parasites and barcoding.

The past 15 years have witnessed a number of molecular studies that aimed to resolve issues of species delineation and phylogeny of mites in the family Tetranychidae. The central part of the mitochondrial COI region has frequently been used for investigating intra- and interspecific variation. All these studies combined yield an extensive database of sequence information of the family Tetranychidae.

Cardinium symbionts induce haploid thelytoky in most clones of three closely related Brevipalpus species.

Bacterial symbionts that manipulate the reproduction of their host to increase their own transmission are widespread. Most of these bacteria are Wolbachia, but recently a new bacterium, named Cardinium, was discovered that is capable of the same manipulations. In the host species Brevipalpus phoenicis (Acari: Tenuipalpidae) this bacterium induces thelytoky by feminizing unfertilized haploid eggs.

Adaptation in the asexual false spider mite Brevipalpus phoenicis: evidence for frozen niche variation.

Because asexual species lack recombination, they have little opportunity to produce genetically variable offspring and cannot adapt to changes in their environment. However, a number of asexual species are very successful and appear to contradict this general view. One such species is the phytophagous mite Brevipalpus phoenicis (Geijskes), a species that is found in a wide range of environments.

Diet-dependent effects of gut bacteria on their insect host: the symbiosis of Erwinia sp. and western flower thrips.

Studies on bacteria in the gut of insect species are numerous, but their focus is hardly ever on the impact on host performance. We showed earlier that Erwinia bacteria occur in the gut of western flower thrips, most probably acquired during feeding. Here, we investigate whether thrips gain a net benefit or pay a net cost because of these gut bacteria.

Phylogeography of the planktonic chaetognath Sagitta setosa reveals isolation in European seas.

Numerous planktonic species have disjunct distribution patterns in the world's oceans. However, it is unclear whether these are truly unconnected by gene flow, or whether they are composed of morphologically cryptic species. The marine planktonic chaetognath Sagitta setosa Müller has a discontinuous geographic distribution over the continental shelf in the northeastern Atlantic, Mediterranean Sea, and Black Sea.

Genetic conflicts over sex ratio: mite-endosymbiont interactions.

Nucleocytoplasmic genetic conflicts arise as a result of asymmetric transmission of cytoplasmic and nuclear genes. Spread of a cytoplasmic element promoting female-biased sex ratios creates selection on nuclear genes for mechanisms that decrease the bias. Here we investigate the conflict over sex ratio between the cytoplasmic bacterium Wolbachia and the two-spotted spider mite Tetranychus urticae Koch.

HYBRID BREAKDOWN BETWEEN TWO HAPLODIPLOID SPECIES: THE ROLE OF NUCLEAR AND CYTOPLASMIC GENES.

A central question in evolutionary biology concerns the population and genetic processes by which new species arise. Here, the genetic basis of hybrid breakdown between two haplodiploid species, Nasonia vitripennis and N. giraulti is investigated.