Forest Thinning Affects Reproduction in Pine Engravers (Coleoptera: Scolytidae) Breeding in Felled Lodgepole Pine Trees

Reproduction in bark beetles (Coleoptera: Scolytidae) is known to be affected by abiotic factors, especiallytemperature, and bythe qualityof individual beetles. Both of these factors are affected byforest structure, yet the effects of forest structure on reproduction in bark beetles have not been widelyshown in Þeld studies. Here we investigate how changes in forest structure due to thinning of mature lodgepole pine, Pinus contorta variety latifolia Engelmann, stands affect reproduction in pine engravers, Ips pini (Say), breeding in felled trees. To do this, we excavated pine engraver gallerysy stems in thinned and unthinned stands at the end of the breeding season. Males in thinned stands attracted more females than in unthinned stands. Also, females in thinned stands extended their egg galleries farther, laid more eggs, and had higher egg densities than in unthinned stands. These results are consistent with increased temperatures in thinned stands, but mayalso be attributable to differences in individual qualityresulting from easier dispersal in thinned stands. Regardless, the observed increases in reproduction likelyreßect higher reproductive success in thinned stands than in unthinned stands, and the effects of thinning on population dynamics of bark beetles should be further investigated.ye

Spin-orbit torque opposing the Oersted torque in ultrathin Co/Pt bilayers

Current-induced torques in ultrathin Co/Pt bilayers were investigated using an electrically driven ferromagnetic resonance technique. The angle dependence of the resonances, detected by a rectification effect as a voltage, was analysed to determine the symmetries and relative magnitudes of the spin-orbit torques. Both anti-damping (Slonczewski) and field-like torques were observed. As the ferromagnet thickness was reduced from 3 to 1 nm, the sign of the sum of the field-like torque and Oersted torque reversed. This observation is consistent with the emergence of a Rashba spin orbit torque in ultra-thin bilayers

Enhanced inverse spin-Hall effect in ultrathin ferromagnetic/normal metal bilayers

Electrically detected ferromagnetic resonance is measured in microdevices patterned from ultra-thin Co/Pt bilayers. Spin pumping and rectification voltages are observed and distinguished via their angular dependence. The spin-pumping voltage shows an unexpected increase as the cobalt thickness is reduced below 2 nm. This enhancement allows more efficient conversion of spin to charge current