Phylogeny and historical biogeography of Gondwanan moss-bugs (Insecta: Hemiptera: Coleorrhyncha: Peloridiidae).

The moss bugs of the Peloridiidae, a small group of cryptic and mostly flightless insects, is the only living family in Coleorrhyncha (Insecta: Hemiptera). Today 37 species in 17 genera are known from eastern Australia, New Zealand, New Caledonia and Patagonia, and the peloridiids are thereby a group with a classical southern Gondwanan distribution. To explicitly test whether the present-day distribution of the Peloridiidae actually results from the sequential breakup of southern Gondwana, we provide the first total-evidence phylogenetic study based on morphological and molecular characters sampled from about 75% of recognized species representing 13 genera. The results largely confirm the established morphological phylogenetic context except that South American Peloridium hammoniorum constitutes the sister group to the remaining peloridiids. A timescale analysis indicates that the Peloridiidae began to diversify in the land mass that is today's Patagonia in the late Jurassic (153 Ma, 95% highest posterior density: 78-231 Ma), and that splitting into the three extant well-supported biogeographical clades (i.e. Australia, Patagonia and New Zealand/New Caledonia) is consistent with the sequential breakup of southern Gondwana in the late Cretaceous, indicating that the current transoceanic disjunct distributions of the Peloridiidae are best explained by a Gondwanan vicariance hypothesis.

Variable wing venation in Agathiphaga (Lepidoptera: Agathiphagidae) is key to understanding the evolution of basal moths.

Details of the ancestral groundplan of wing venation in moths remain uncertain, despite approximately a century of study. Here, we describe a 3-branched subcostal vein, a 5-branched medial vein and a 2-branched cubitus posterior vein on the forewing of Agathiphaga vitiensis Dumbleton 1952 from Vanuatu. Such veins had not previously been described in any Lepidoptera. Because wing veins are typically lost during lepidopteran evolutionary history, rarely-if ever-to be regained, the venation of A. vitiensis probably represents the ancestral character state for moths. Wing venation is often used to identify fossil insects as moths, because wing scales are not always preserved; the presence of a supposedly trichopteran 3-branched subcostal vein in crown Lepidoptera may decrease the certainty with which certain amphiesmenopteran fossils from the Mesozoic can be classified. And because plesiomorphic veins can influence the development of lepidopteran wing patterns even if not expressed in the adult wing, the veins described here may determine the location of wing pattern elements in many lepidopteran taxa.

Small but powerful, the primary endosymbiont of moss bugs, Candidatus Evansia muelleri, holds a reduced genome with large biosynthetic capabilities.

Moss bugs (Coleorrhyncha: Peloridiidae) are members of the order Hemiptera, and like many hemipterans, they have symbiotic associations with intracellular bacteria to fulfill nutritional requirements resulting from their unbalanced diet. The primary endosymbiont of the moss bugs, Candidatus Evansia muelleri, is phylogenetically related to Candidatus Carsonella ruddii and Candidatus Portiera aleyrodidarum, primary endosymbionts of psyllids and whiteflies, respectively. In this work, we report the genome of Candidatus Evansia muelleri Xc1 from Xenophyes cascus, which is the only obligate endosymbiont present in the association. This endosymbiont possesses an extremely reduced genome similar to Carsonella and Portiera. It has crossed the borderline to be considered as an autonomous cell, requiring the support of the insect host for some housekeeping cell functions. Interestingly, in spite of its small genome size, Evansia maintains enriched amino acid (complete or partial pathways for ten essential and six nonessential amino acids) and sulfur metabolisms, probably related to the poor diet of the insect, based on bryophytes, which contains very low levels of nitrogenous and sulfur compounds. Several facts, including the congruence of host (moss bugs, whiteflies, and psyllids) and endosymbiont phylogenies and the retention of the same ribosomal RNA operon during genome reduction in Evansia, Portiera, and Carsonella, suggest the existence of an ancient endosymbiotic Halomonadaceae clade associated with Hemiptera. Three possible scenarios for the origin of these three primary endosymbiont genera are proposed and discussed.

Diversity of bacterial endosymbionts and bacteria-host co-evolution in Gondwanan relict moss bugs (Hemiptera: Coleorrhyncha: Peloridiidae).

Many hemipterans are associated with symbiotic bacteria, which are usually found intracellularly in specific bacteriomes. In this study, we provide the first molecular identification of the bacteriome-associated, obligate endosymbiont in a Gondwanan relict insect taxon, the moss bugs (Hemiptera: Coleorrhyncha: Peloridiidae), which represents one of the oldest lineages within the Hemiptera. Endosymbiotic associations of fifteen species of the family were analysed, covering representatives from South America, Australia/Tasmania and New Zealand. Phylogenetic analysis based on four kilobases of 16S-23S rRNA gene fragments showed that the obligate endosymbiont of Peloridiidae constitute a so far unknown group of Gammaproteobacteria which is named here 'Candidatus Evansia muelleri'. They are related to the sternorrhynchous endosymbionts Candidatus Portiera and Candidatus Carsonella. Comparison of the primary-endosymbiont and host (COI + 28S rRNA) trees showed overall congruence indicating co-speciation the hosts and their symbionts. The distribution of the endosymbiont within the insect body and its transmission was studied using FISH. The endosymbionts were detected endocellularly in a pair of bacteriomes as well as in the 'symbiont ball' of the posterior pole of each developing oocyte. Furthermore, ultrastructural analysis of the Malpighian tubules revealed that most host nuclei are infected by an endosymbiotic, intranuclear bacterium that was determined as an Alphaproteobacterium of the genus Rickettsia.

Seed dispersal by weta.

Weta are giant, flightless grasshoppers that are endemic to New Zealand. In the absence of native mammals, weta are thought to perform similar ecological functions. As such, they might be expected to be important seeds dispersers. However, insects are not known to consume fleshy fruits and to disperse seeds after gut passage. We conducted a series of observations and experiments to test whether weta form mutualistic partnerships with fleshy-fruited plants as seed dispersers, similar to small mammals elsewhere in the world. Results showed that weta are indeed effective seeds dispersers, providing an example of ecological convergence between unrelated organisms.