Meers Theresa L, Cloyd Raymond A
Department of Natural Resources and Environmental Sciences, University of Illinois, Urbana, IL 61811, USA.
J Econ Entomol. 2005 Dec;98(6):1937-42. doi: 10.1093/jee/98.6.1937.
Fungus gnats, Bradysia spp., are major insect pests in greenhouses. Adult female fungus gnats prefer to lay eggs in growing medium that is microbially active or that contains high amounts of peat moss or hardwood bark. However, egg-laying preference has not been demonstrated quantitatively. This study was designed to determine whether fungus gnat Bradysia sp. nr. coprophila females prefer any of the three soilless growing media provided. The three soilless growing media tested were Metro-Mix 560 with Scott's Coir, Sunshine LC1 Mix, and Universal SB 300 Mix. Initially, the egg-laying potential of the fungus gnat species used in this study was assessed by dissecting mated females after 24, 48, and 72 h. For the egg-laying preference experiment, adults that emerged from pupae were aspirated into a plastic vial, sexed, and then allowed to mate for 24 h. Individual mated females were released into an experimental chamber (15 by 15 by 5-cm plastic container) consisting of four 6-cm petri dishes, three of which contained soilless growing media and one with filter paper (control). In total, there were 50 experimental chambers, with each chamber representing a replication. Females remained in the experimental chambers for 48 h after which the growing media were processed using a flotation/extraction method. The number of eggs laid by female fungus gnats ranged from 21 to 217 with most eggs recovered after 48 h (141.0 +/- 9.3). There were no significant differences among the three soilless growing media in terms of number of eggs laid, although all three growing media were significantly different from the filter paper with higher numbers of eggs laid in the soilless growing media than the filter paper. Despite no significant difference among the growing media in the number of eggs laid, fungus gnat females tended to lay eggs more often, based on the number of petri dishes in which at least one egg was laid, in Metro-Mix 560 (86%) than Sunshine LC1 (66%), Universal SB 300 (52%), or filter paper (18%). Based on the results of this study, female fungus gnats may not prefer a specific growing medium for oviposition. However, fungus gnat females may rely on other factors not tested in this study such as moisture content and volatiles emitted from growing media in their decision where to lay eggs.
菌蚊（Bradysia spp.）是温室中的主要害虫。成年雌性菌蚊更喜欢在微生物活跃或含有大量泥炭藓或硬木树皮的生长介质中产卵。然而，产卵偏好尚未得到定量证明。本研究旨在确定菌蚊Bradysia sp. nr. coprophila的雌性是否偏好所提供的三种无土生长介质中的任何一种。所测试的三种无土生长介质分别是含斯科特椰壳纤维的Metro-Mix 560、阳光LC1混合介质和通用SB 300混合介质。最初，通过在24、48和72小时后解剖已交配的雌性来评估本研究中使用的菌蚊物种的产卵潜力。对于产卵偏好实验，将从蛹中羽化出的成虫吸入塑料瓶中，进行性别区分，然后让它们交配24小时。将单独的已交配雌性放入一个实验箱（15×15×5厘米的塑料容器）中，该实验箱由四个6厘米的培养皿组成，其中三个装有无土生长介质，一个装有滤纸（对照）。总共有50个实验箱，每个实验箱代表一次重复。雌性在实验箱中停留48小时，之后使用浮选/提取方法处理生长介质。雌性菌蚊产下的卵数在21至217个之间，大多数卵在48小时后被回收（141.0±9.3）。在产卵数量方面，三种无土生长介质之间没有显著差异，尽管所有三种生长介质与滤纸相比都有显著差异，无土生长介质中的产卵数高于滤纸。尽管生长介质在产卵数量上没有显著差异，但根据至少有一个卵的培养皿数量来看，菌蚊雌性在Metro-Mix 560（86%）中产卵的频率往往高于阳光LC1（66%）、通用SB 300（52%）或滤纸（18%）。根据本研究的结果，雌性菌蚊可能不偏好特定的生长介质用于产卵。然而，菌蚊雌性可能依赖于本研究中未测试的其他因素，如生长介质的含水量和挥发物，来决定在哪里产卵。
