Due to concerns with synthetic neurotoxic insecticides used in insect pest management, alternative control methods are sought. Methoprene is a juvenile hormone analogue, which is well-known for its lethal effects on immature insects, and is registered as a stored-grain insecticide in the U.S.A. and Australia. However, less is known about its sub-lethal effects. Experiments were conducted to investigate the effects of methoprene (Diacon II) on heat tolerance, cold tolerance and progeny production of Tribolium castaneum (Herbst) when late-instar larvae or adults were exposed to wheat treated with methoprene. Methoprene at 3.33 ppm or higher, reduced heat tolerance of adults at 46ºC. In contrast, methoprene did not affect the heat tolerance of larvae. Cold tolerance and cold acclimation of both adults and larvae was not affected by methoprene. Exposure of larvae to 0.001 or 0.0165 ppm of methoprene on wheat had 37 and 72% reduction in adult emergence, respectively. The surviving adults had normal movement, but their progeny production was reduced by 71%. Males were affected more than females. Exposure of adults to methoprene (66.6 ppm) did not reduce progeny production. Methoprene is used as a surface treatment to control insects in empty grain bins, processing facilities and warehouses. Experiments were conducted to assess the effect of surface material, temperature and cleaning practices on methoprene residual efficacy. A bioassay with late-instar larvae at 30ºC until adult emergence was used to measure methoprene residual efficacy. Methoprene applied at the label rate (0.0003 mg/cm2) on varnished wood, held at 20, 30 or 35ºC for 24 weeks, prevented all development of larvae into adults. Conversely, concrete surfaces allowed 22% adult emergence after 8 weeks and 69% after 24 weeks. Temperatures, 20, 30 or 35ºC, that the concrete surfaces were held before the bioassay, did not affect this decline in efficacy. Presence of flour or repeated removal of flour (cleaning) reduced the efficacy of methoprene on concrete surfaces, but not on varnished wood. Maintaining concrete surfaces at 65ºC for 48 hours did not reduce efficacy. The implications of these results are discussed in the context of controlling stored-product insects, as well as insect physiology.

Due to concerns with synthetic neurotoxic insecticides used in insect pest management, alternative control methods are sought. Methoprene is a juvenile hormone analogue, which is well-known for its lethal effects on immature insects, and is registered as a stored-grain insecticide in the U.S.A. and Australia. However, less is known about its sub-lethal effects. Experiments were conducted to investigate the effects of methoprene (Diacon II) on heat tolerance, cold tolerance and progeny production of Tribolium castaneum (Herbst) when late-instar larvae or adults were exposed to wheat treated with methoprene. Methoprene at 3.33 ppm or higher, reduced heat tolerance of adults at 46ºC. In contrast, methoprene did not affect the heat tolerance of larvae. Cold tolerance and cold acclimation of both adults and larvae was not affected by methoprene. Exposure of larvae to 0.001 or 0.0165 ppm of methoprene on wheat had 37 and 72% reduction in adult emergence, respectively. The surviving adults had normal movement, but their progeny production was reduced by 71%. Males were affected more than females. Exposure of adults to methoprene (66.6 ppm) did not reduce progeny production. Methoprene is used as a surface treatment to control insects in empty grain bins, processing facilities and warehouses. Experiments were conducted to assess the effect of surface material, temperature and cleaning practices on methoprene residual efficacy. A bioassay with late-instar larvae at 30ºC until adult emergence was used to measure methoprene residual efficacy. Methoprene applied at the label rate (0.0003 mg/cm2) on varnished wood, held at 20, 30 or 35ºC for 24 weeks, prevented all development of larvae into adults. Conversely, concrete surfaces allowed 22% adult emergence after 8 weeks and 69% after 24 weeks. Temperatures, 20, 30 or 35ºC, that the concrete surfaces were held before the bioassay, did not affect this decline in efficacy. Presence of flour or repeated removal of flour (cleaning) reduced the efficacy of methoprene on concrete surfaces, but not on varnished wood. Maintaining concrete surfaces at 65ºC for 48 hours did not reduce efficacy. The implications of these results are discussed in the context of controlling stored-product insects, as well as insect physiology.

This research project gauges producer demand on the Canadian Prairies for the attributes of new hypothetical varieties of winter wheat. Data collected from a survey of producers in Western Canada is used to determine the values and attitudes of producers regarding new winter wheat variety traits with a focus on increased winter survival rates and increased waterfowl nesting habitat. Increased nesting habitat was found to have a small negative but significant impact on the decision to adopt hypothetical winter wheat varieties; however winter kill rates and gross profit had a large positive effect on its adoption and expansion. Other important drivers of the decision to adopt hypothetical winter wheat varieties are also analyzed. Policy implications include potential guidance of incentives for environmentally friendly farming practices, and the provision of information to winter wheat breeding programs about the needs of producers.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2006. / Härtill 4 uppsatser.

Dairy calves require nutrients for maintenance and growth, but in cold weather, the body alters physiologic processes to control body temperature through thermogenesis, which increases its requirements. In this regard, it is important a better understanding of how different feeding managements act in the calf thermogenesis, performance and health when raised in temperatures below thermoneutral conditions. Based on that, two studies were performed. The first study evaluated thermoregulation, performance and blood metabolites in thirty newborn calves fed 10%, 15% or 20% BW of colostrum. At 24h of life, calves were placed in a temperature-controlled chamber at 10ºC for 150 min. After the cold challenge, calves were individually housed in ambient temperature facilities (26.8 ± 5.9°C) until weaning. Calves given 15% or 20% of BW as colostrum exhibited increased thermoregulatory responses during cold challenge and increased immunity responses during preweaning. The second study compared performance and production cost of 75 calves fed milk replacer (MR) or whole milk (WM) and a traditional starter (TS) or an alternative starter (AS) during low environmental temperatures (1.4 ± 9.2°C). Calves were assigned to one of five treatment groups in a 2 x 2 + 1 factorial. The first treatment was a negative control (NC), 4 L/d of MR from d1 to 49; 2L/d of MR from d 50 to 56 of the study and ad libitum TS (commercial texturized ration). The others four treatments were a high rate (HR) of MR or WM (6L/d from d 1 to 7, 8 L/d from d 8 to 35, 4L/d from d 36 to 42, and 2 L/d from d 43 to 49 of the study) and ad libitum AS (cracked corn from d 1 to 21, low protein grower from d 22 to 28, high protein grower from d 29 to 49 of the study) or TS. After weaning, animals were maintained in group hutches in the same environment until 12 weeks of life. Restricted liquid feeding provided higher economic efficiency. However, the final BW was higher for calves fed HRTS. In addition, feeding calves higher volumes of WM increased growth and decreased morbidity. Besides, replacing commercial TS with an AS in high rate of nutrition presented minimal impact on performance. / Bezerros leiteiros necessitam de nutrientes para mantença e crescimento, contudo, em baixas temperaturas, o corpo altera os processos fisiológicos para controlar a temperatura corporal por meio da termogênese, aumentando a exigência. Neste sentido, se torna importante uma melhor compreensão de como diferentes manejos alimentares atuam na termogênese, no desempenho e na saúde de bezerros criados em temperaturas abaixo das condições de termoneutralidade. Com base nisso, dois estudos foram realizados. O primeiro estudo avaliou a termorregulação, o desempenho e os metabólitos sanguíneos de trinta bezerros recém nascidos alimentados com 10%, 15% ou 20% de colostro em porcentagem de peso corporal. Vinte e quatro horas após o nascimento, os bezerros foram colocados em uma câmara de temperatura controlada a 10°C por 150 min. Após o desafio do frio, os bezerros foram individualmente alojados em instalação à temperatura ambiente (26,8 ± 5,9°C) até o desaleitamento. Bezerros que receberam 15% ou 20% de colostro exibiram aumento das respostas termorreguladoras durante o desafio pelo frio e aumento das respostas de imunidade durante o aleitamento. O segundo estudo comparou o desempenho e os custos de produção de 75 bezerras alimentadas com sucedâneo (S) ou leite (L) e uma ração tradicional (RT) ou uma ração inicial alternativa (RA) durante baixas temperaturas ambientais (1,4 ± 9,2°C). As bezerras foram designados para um dos cinco tratamentos em fatorial 2 x 2 + 1 O primeiro tratamento foi o controle negativo (CN), 4 L/d de S do d1 ao 49; 2L/d de S do d 50 ao 56 do estudo e RT ad libitum (ração comercial texturizada). Os outros quatro tratamentos foram alta taxa (AT) de S ou L (6L/d do d 1 ao 7, 8 L/d do d 8 ao 35, 2L/d do d 36 ao 42, e 1 L/d do d 43 ao 49 do estudo) e RA ad libitum (milho quebrado do d 1 ao 21, ração de crescimento com baixa proteína do d 22 ao 28, ração de crescimento alta proteína do d 29 ao 49 do estudo) ou RT. Após o desaleitamento, os animais foram mantidos em baias coletivas até 12 semanas de vida. Dieta líquida restrita promoveu maior eficiência econômica. No entanto, o peso final foi maior para bezerras alimentadas com ATRT. Adicionalmente, alimentar bezerras com maior volume de L aumentou o crescimento e diminui morbidade. Além disso, substituir RT comercial por uma RA em altas taxas de nutrição apresentou mínimo impacto no desempenho.

京都大学 / 0048 / 新制・論文博士 / 博士(理学) / 乙第13321号 / 論理博第1568号 / 新制||理||1663(附属図書館) / 名古屋大学大学院生命農学研究科 / (主査)教授 石田 厚, 教授 田村 実, 教授 永益 英敏 / 学位規則第4条第2項該当 / Doctor of Science / Kyoto University / DFAM

Subalpine larch (Larix lyallii Parl.) has a narrow ecological niche at timberline in the Cascade Range and the Rocky Mountains of western North America. Demographic factors, including a long generation time (average 500 years) and a late arrival at sexual maturity (100-200 years), make it unlikely that this species will be able to adapt to predicted climate change. A better understanding of genetic structure and genetic diversity is necessary in order to effectively manage this species for future generations. Foliage from 62 populations of subalpine larch was collected in order to elucidate the range-wide population genomics of the species. DNA was extracted and a next-generation sequencing method, restriction site associated DNA sequencing (RAD-seq), was used to generate genome-wide single nucleotide polymorphism (SNP) marker data. Three genetically differentiated clusters were identified via principal components analysis, a discriminant analysis of principal components and Bayesian STRUCTURE analysis: the Cascade Range, the southern Rocky Mountains and the northern Rocky Mountains. A monophyletic group in the central Rocky Mountains was also identified in a dendrogram of genetic distance but this group had weak bootstrap support (49%), meaning genetic differentiation depends on relatively few genetic variants. Genetically differentiated groups should be prioritized for future management and conservation efforts. Negative values of Tajima’s D and preferred demographic scenarios generated by coalescent simulations indicated that 15 populations all have a recent history of expansion. Genetic diversity within these populations was found to be moderate (HO = 0.15 – 0.20), inbreeding coefficients were found to be high (FIS = 0.15 – 0.25) and genetic differentiation among populations was found to be high (average FST = 0.18). These results indicated that fragmentation driven by Holocene warming may have resulted in reduced effective population sizes. Smaller populations experience stronger genetic drift and an increased likelihood of inbreeding, which may hinder an adaptive response to natural selection. Still, parameter estimates for preferred demographic scenarios suggested a minimum effective population size of around 20,000 individuals, which is not considered small by most conservationists. A final study of 18 populations found local adaptation to cold temperature in the northern portion of the species range. In all seasons, populations from the northern Rocky Mountains had significantly higher cold tolerance than populations from the central Canadian Rocky Mountains and the northern Cascades. Winter cold tolerance showed strong clines associated with the frost-free period and degree days below zero. These two climate variables explained 65% of the explainable variance in phenotype when redundancy analysis models were conditioned on geography. Seven SNPs were identified that explained a significant portion of the variance in winter cold tolerance. Range-wide, additional SNPs were identified as FST outliers and/or as significantly correlated with environmental gradients, even after correcting for neutral genetic structure. Together, the results of this work indicate that dispersal, neutral evolutionary processes and natural selection have all played important roles in shaping patterns of genetic variation across the natural range of subalpine larch. All of these factors should be considered during the development of management and conservation strategies for this high-elevation conifer species. / Graduate

The redbanded stink bug, Piezodorus guildinii (Westwood) (Hemiptera: Pentatomidae), is a non-native pest of soybeans in the Americas outside of the Carribean. Mortality of overwintering adults due to cold exposure has been implicated as a major driver of interannual fluctuations in the occurrence of P. guildinii in the southeastern United States, but formal investigations of drivers, including factors other than cold temperatures, are rare. We conducted overwintering assays with field-collected P. guildinii to quantify survival and coupled historical occurrence with climatic data to develop a species distribution model. We found that leaf litter provides substantial insulation from lethal temperatures and thus increases the potential for overwintering survival of P. guildinii. Our species distribution model indicates that the northern extent of the insect’s range is limited by winter temperatures, but that can potentially expand the range hundreds of kilometers in a growing season.

京都大学 / 新制・論文博士 / 博士(医学) / 乙第13535号 / 論医博第2275号 / 新制||医||1065(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 伊達 洋至, 教授 湊谷 謙司, 教授 小林 恭 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23744号 / 理博第4834号 / 新制||理||1691(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 工藤 洋, 准教授 本庄 三恵, 教授 松下 智直 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM