The walnut twig beetle, Pityophthorus juglandis Blackman (Coleoptera: Scolytidae), vectors the fungus Geosmithia morbida, which has been implicated in thousand cankers disease of walnut. Little is known about the flight behavior of the insect across seasons, or about the variability in its flight patterns with weekly fluctuations in weather. We sampled flying adults weekly over a 142-week period (from 29 August, 2011 to 2 June, 2014) with 12-unit black plastic multiple funnel traps baited with a male-produced aggregation pheromone in California, USA. Up to 5000 beetles were captured per trap per week, although catches in most weeks were less than 100 insects. Trap catches were regressed against terms for precipitation, solar radiation, vapor pressure, air temperature, relative humidity, wind speed, and trap catches in preceding weeks. The number of beetles captured in each of the preceding two weeks explained most variation in a current week's catch. This strong temporal autocorrelation was present in regression models developed for males, females, and both sexes pooled. These models were improved by including two environmental variables. Captures of P. juglandis increased with mean weekly air temperature and decreased with increasing mean minimum relative humidity. The percentage of variation in male, female, or total trap catch explained by the temporal variables and the two environmental variables in these multiple regression models ranged from 72% to 76%. While the flight of this invasive insect will likely be affected by site-specific factors as it spreads to new areas, the strong temporal correlation present in this system may provide a useful starting point for developing flight models for newly invaded areas.

中文翻译：

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天气对入侵树皮甲虫（Pityophthorus juglandis）飞行的影响。


核桃小枝甲虫 Pityophthhorus juglandis Blackman（鞘翅目：小蠹科）是真菌 Geosmithia morbida 的媒介，这种真菌与核桃千口溃疡病有关。人们对这种昆虫跨季节的飞行行为以及其飞行模式随天气每周波动的变化知之甚少。我们在美国加利福尼亚州的 142 周（从 2011 年 8 月 29 日到 2014 年 6 月 2 日）内，使用 12 个黑色塑料多漏斗陷阱，每周对飞行成虫进行采样，并用雄性产生的聚集信息素作为诱饵。每个陷阱每周捕获多达 5000 只甲虫，但大多数周的捕获量不足 100 只昆虫。陷阱捕获量根据降水量、太阳辐射、蒸气压、气温、相对湿度、风速和前几周的陷阱捕获量进行回归。前两周捕获的甲虫数量解释了本周捕获量的大部分变化。这种强烈的时间自相关存在于为男性、女性和两性汇总开发的回归模型中。这些模型通过包含两个环境变量得到了改进。胡桃木的捕获量随着每周平均气温的增加而增加，并随着平均最低相对湿度的增加而减少。在这些多元回归模型中，由时间变量和两个环境变量解释的雄性、雌性或总陷阱捕获量的变化百分比范围为 72% 至 76%。虽然这种入侵昆虫的飞行在传播到新区域时可能会受到特定地点因素的影响，但该系统中存在的强时间相关性可能为开发新入侵区域的飞行模型提供有用的起点。