The pine bark beetle, Dendroctonus armandi, is a native pest restricted to forests in the Qinling Mountains in China. There was an outbreak of this species there that affected over 0.36 million hectares of pine forest. We hypothesized that there are differences between the numbers of beetles captured by traps baited with various combinations of candidate semiochemicals extracted from the hindguts of D. armandi. In order to determine whether a better operational lure could be developed for D. armandi, we analyzed the volatiles in extracts of the hindgut of D. armandi and tested various combinations of candidate semiochemicals. The GC-MS and GC-FID analyses of volatiles in the extracts of the hindguts of D. armandi collected at different stages of the attack revealed that they are mainly a-pinene, b-caryophyllene and (+)-3-carene with minor amounts of myrcene, limonene, verbenol and verbenone. We tested various combinations of these candidate semiochemicals in order to determine an optimal blend. Our results suggest that the addition of b-caryophyllene to either a-pinene, or blends of a-pinene and other candidate semiochemicals, significantly enhanced the attractiveness of the lures for D. armandi. Field trapping experiments indicated that the blends that included b-caryophyllene, myrcene and other candidate semiochemicals resulted in significantly higher trap catches (161–243% higher) than a-pinene alone. Therefore, a simple lure consisting of a-pinene and b-caryophyllene would be an optimal blend for D. armandi. We conclude that this blend of semiochemicals may provide a better method of reducing the numbers of D. armandi in forest ecosystem., Shou-An Xie, Shu-Jie LV., and Obsahuje seznam literatury
The spawning migration from Moravka reservoir to the Moravka river tributary of brown trout in autumn (October – November) lasted 22, 24, and 27 days respectively in the seasons 2002–2004. In 2002, 187 fish were trapped, while the number of trapped spawners increased to 447 in 2003 and 2230 in 2004. Spawning males were significantly longer than females (PoC in the reservoir. The peak of spawning, in all three seasons, took place between 28 October and 3 November, and the river water temperature varied from 6 to 8oC. The spawning in 2002 was more nocturnal (between 8:00 p.m. to 6:00 a.m.) than diurnal (P<0.01) and the diel activity showed the multimodal distribution. There were no large or significant differences between the diurnal and nocturnal migrations in 2003 and 2004. Single environmental variables and their interaction were significantly related to the spawning migration only in 2003 and 2004 (P<0.001).
Social wasps are often considered as nuisance pests in urban environments and are often controlled by using traps. The majority of commercially produced traps for catching wasps have yellow as the dominant colour around the trap entrance. However, the observations on the function of yellow as an attractant for wasps are controversial. The efficiency of yellow, compared with green striped (N = 15) and yellow and green striped beer traps (N = 15) was evaluated. According to the results, yellow does not have a specific role as an attractant for wasps of the genera Vespula Linnaeus and Dolichovespula (Rohwer). For wasps, it may be the bait that is the major lure and it might be sufficient on its own for both control and monitoring purposes.