Assessing the contribution of geography and host use to genetic structure in New York populations of the parasitoid wasp, Aphidius ervi

Host-associated differentiation (HAD) has been shown to be important in generating genetic differentiation within herbivorous insects, but the applicability of HAD to other parasitic taxonomic groups remains unclear. For example, parasitoid wasps that attack herbivorous insects share many similar life habits with their hosts, suggesting that HAD may also be a prevalent and important mechanism in this group. I tested for the genetic signature of HAD in the parasitoid wasp, Aphidius ervi, that attacks aphids. Aphidius ervi is a biocontrol agent that uses many species of pest aphids including the clover and alfalfa host-races of the pea aphid (Acyrthospihon pisum). The pea aphid host races differ in their defenses and resource quality as hosts for A. ervi. I assessed allelic variation from six microsatellite loci across sixteen A. ervi populations along a 200 km transect in New York State to examine genetic structure in relation to pea aphid host race use. Results from AMOVA and pairwise FST analyses indicated that there is no genetic structure in A. ervi due to HAD, and there was no genetic structure across the sampled range. These findings suggest that A. ervi populations are connected by high levels of gene flow that likely swamp out selection for specialization on the pea aphid host races of A. ervi. At least for A. ervi, the spatiotemporal distribution of hosts as well as the high dispersal rate suggest that HAD is unlikely to be a mechanism of genetic differentiation among populations

Massacre of Canadian Army Medical Corps personnel after the sinking of HMHS Llandovery Castle and the evolution of modern war crime jurisprudence

Events after the sinking of the hospital ship Llandovery Castle on June 27, 1918, by the German submarine U-86 outraged Canadians. Survivors aboard a single life raft gave evidence that many of the 234 souls lost had made it to lifeboats but were rammed and shot by the submarine. Many of those who died were nurses. Three German officers were charged with war crimes after the war. The submarine’s captain evaded capture. The remaining two officers’ defence that they were following the captain’s orders failed and they were convicted. This ruling was used as a precedent to dismiss similar claims at the war crime trials after the Second World War. It is also the basis of the order given to members of modern militaries, including the Canadian Armed Forces, that it is illegal to carry out an illegal order

Using a Multi-Institutional Ensemble of Watershed Models to Assess Agricultural Conservation Effectiveness in a Future Climate

This study investigates the combined impacts of climate change and agricultural conservation on the magnitude and uncertainty of nutrient loadings in the Maumee River Watershed, the second-largest watershed of the Laurentian Great Lakes. Two scenarios — baseline agricultural management and increased agricultural conservation — were assessed using an ensemble of five Soil and Water Assessment Tools driven by six climate models. The increased conservation scenario included raising conservation adoption rates from a baseline of existing conservation practices to feasible rates in the near future based on farmer surveys. This increased adoption of winter cover crops on 6%–10% to 60% of cultivated cropland; subsurface placement of phosphorus fertilizers on 35%–60% to 68% of cultivated cropland; and buffer strips intercepting runoff from 29%–34% to 50% of cultivated cropland. Increased conservation resulted in statistically significant (p ≤ 0.05) reductions in annual loads of total phosphorus (41%), dissolved reactive phosphorus (18%), and total nitrogen (14%) under the highest emission climate scenario (RCP 8.5). While nutrient loads decreased with increased conservation relative to baseline management for all watershed models, different conclusions on the true effectiveness of conservation under climate change may be drawn if only one watershed model was used.publishedVersio