Paleogenomics reveals independent and hybrid origins of two morphologically distinct wolf lineages endemic to Japan

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Species richness in Madeiran land snails, and its causes

Aim  To unravel the reasons why a group of islands of 800 km² area should support over 200 extant land snail species.
Location  The temperate Atlantic Madeiran archipelago.
Methods  Distributional surveys and model testing.
Results  Repeated volcanic events have changed the topography of the islands and created periodic further isolates. There has been climatic fluctuation and varying sea level. Individual locations are not species-rich, but there is replacement from one subregion to another. Evidence of competitive interactions is lacking.
Main conclusions  High diversity results from the fortuitous coincidence of rates of geological and climatic change and isolation on the one hand, and migration and genetic divergence on the other. Hubbell's neutral model of biodiversity explains species richness if a factor is added describing structural instability or periodicity, here called the geodetic rate. This geodetic, biological interaction can explain why some archipelagos are species-rich.     

Post-glacial range fragmentation is responsible for the current distribution of Potentilla matsumurae Th. Wolf (Rosaceae) in the Japanese archipelago

Aim We aimed to elucidate how the current geographic distribution of alpine plants in the Japanese archipelago was shaped during Quaternary climatic oscillations, using Potentilla matsumurae as a case study. According to previous phylogeographic studies, post‐glacial range fragmentation (vicariance scenario) and stepwise migration (dispersal scenario) are both possible. We thus aimed to assess which scenario is more probable for the distribution changes of alpine plants in the Japanese archipelago. Location The alpine zone in the Japanese archipelago. Methods Using amplified fragment length polymorphism we determined the genotype of 161 individuals of P. matsumurae from 22 populations. Relationships among individuals and populations were examined using principal coordinates analysis and a neighbour‐joining (NJ) tree, respectively. To examine the genetic population structure, we performed analysis of molecular variance (amova ) and structure analysis. Results Differentiation between central Honshu and northern Japan was not very strong based on the principal coordinates analysis among individuals, the NJ tree of populations (59% bootstrap support), or amova (12% of genetic variation). Moreover, structure analysis did not detect clear geographic differentiation across populations. Although the populations in central Honshu were structured geographically (Mantel test: r = 0.45, P < 0.005; NJ tree), those in northern Japan did not exhibit geographic structure regardless of geographic distance (Mantel test: r = 0.26, P = 0.03; NJ tree). Population relationships in the NJ tree did not always reflect the geographic location. Main conclusions The current geographic structure of P. matsumurae could not be explained by stepwise migration. This suggests that a single continuous distribution during the last glacial period was later fragmented, perhaps by recovering forest, during the post‐glacial period, resulting in the current distribution and phylogeographic structure of P. matsumurae. Our data support the vicariance scenario.     

The impact of exotic parasitoids on populations of a native Hawaiian moth assessed using life table studies

The impact of alien species on native organisms is a cause for concern worldwide, with biological invasions commonplace today. Suppression efforts targeting many invasive species have included introductions of biological control agents. The numerous releases of biological control agents in the Hawaiian archipelago have resulted in considerable concern for non-target impacts, due to high levels of non-target parasitism observed to occur in some cases. This study investigated the impact of introduced Hymenoptera parasitoids on a Hawaiian moth. The endemic Hawaiian moth Udea stellata (Butler) has seven alien parasitoids associated with it, two purposely introduced, three adventive, and two of uncertain origin. The objective of this study was to determine the relative contribution of the seven parasitoid species to the population dynamics of U. stellata by constructing partial life tables. Marginal attack rates and associated k-values were calculated to allow comparison of mortality factors between experimental sites. Sentinel larvae were deployed on potted host plants and left in the field for 3-day intervals in open and exclusion treatments. The factors that contributed to total mortality in the open treatment were: disappearance (42.1%), death due to unknown reasons during rearing (16.5%) and parasitism (4.9%). The open treatment incurred significantly higher larval disappearance compared to the exclusion treatment (7.8%), which suggests that in large part disappearance is the result of predation. Adventive parasitoids inflicted greater total larval mortality attributable to parasitism (97.0%) than purposely introduced species (3.0%).