福寿螺表型性状的空间尺度变异

格局和尺度是生态学的核心概念。尺度的变化可能导致生态学格局的改变。入侵物种性状的变异会对种群的建立和扩散产生重要的影响。为了研究入侵物种福寿螺(Pomacea canaliculata)表型性状的尺度变异并推测可能的作用机制,在广东省开展了福寿螺的体质量、体高、体宽、壳口宽4个表型性状在城市、乡镇、生境、样方、个体5个空间尺度上变异的研究。通过拟合混合模型,进行方差分解,结果发现个体和样方差异解释了近80%的性状变异,生境的差异解释了除体重外其他性状的剩余变异;除体重外乡镇和城市尺度上性状的变异并不明显。结果进一步表明,区域尺度的过程如气候特征等对福寿螺表型性状变异不起主要作用;福寿螺种群特征的研究及防控的重点应考虑其遗传结构特征及局部尺度环境因素。通过不同尺度下性状的变异系数和频度分布曲线的分析,进一步验证了以上结果。     

不同施药方式对福建烟蚜抗药性及活性酶的影响

本文采用连续施用和轮换施用农药方式对福建烟区烟蚜进行抗药性及其体内酶变化的测定,研究结果表明,在连续施用3次、5次、7次和9次后,施用灭多威后的烟蚜抗性分别增长了1.397倍、2.608倍、4.891倍和7.598倍;施用吡虫啉则分别增长了1.717倍、2.114倍、2.861倍和4.169倍;施用高效氯氟氰菊酯则分别...     

夹竹桃皂甙对福寿螺的毒杀效果及其对水稻幼苗的影响

室内条件下研究了夹竹桃皂甙对福寿螺的杀灭效果及其对水稻幼苗的影响。结果表明,福寿螺的致死率随着皂甙浓度的增加和处理时间的延长而显著上升,其中50mg/L 浓度皂甙处理48h的致死率达100%,与0.156g/L氯硝柳胺水溶液的灭螺效果相当。皂甙对福寿螺的杀灭效果与福寿螺的大小有关。皂甙对壳高h＜10 mm的福寿螺的杀螺效果最好, 而对20≤h<30 mm的杀螺效果最差。水稻幼苗的存活率随着皂甙浓度的增加而显著增加,且低浓度皂甙处理24h也具有较高的值。此外,采用水培方法研究了皂甙对水稻幼苗鲜重的影响。高浓度(≥40 mg/L)的皂甙处理7d显著地抑制了水稻幼苗根部和地上部分的鲜重,其中对根部的影响大于地上部分。当处理时间延长到14d时,皂甙对水稻幼苗鲜重的抑制作用逐渐减弱,仅50mg/L 皂甙处理对根部鲜重有显著地抑制。而在氯硝柳胺水溶液处理下,水稻幼苗停止生长。综合结果表明夹竹桃皂甙是一种环境友好且能高效防治福寿螺的灭螺剂。     

入侵种小管福寿螺对本土物种 梨形环棱螺的生态挤压作用

在世界范围内,物种入侵正成为一个影响经济发展、公众健康的重大生态事件。为了探究入侵物种小管福寿螺(Pomacea canaliculata)对本土近生态位物种的生态挤压作用,选择了梨形环棱螺(Bellamya purificata)作为受试动物,设置直接生态竞争实验和间接分泌物胁迫实验两类实验。直接生态竞争实验中两种螺直接竞争生存资源,而间接分泌物胁迫实验中则观测两种受试螺分泌物对彼此与自身种群的影响。为了模拟野外不同水体的竞争情况,设置了两种密度,即每组共计6只受试螺(低密度组)及每组共计12只受试螺(高密度组),在两种密度下设两种螺不同比例的个体组合。结果显示,两类实验中,小管福寿螺的体重相对变化与生存率都优于梨形环棱螺。直接竞争实验小管福寿螺体重相对变化率显著优于梨形环棱螺(P 0.05),但二者生存率无显著差异;低密度组中,福寿螺与梨形环棱螺的体重相对变化及生存率均无显著差异,而高密度组中,当梨形环棱螺个体数极多时(8只),其体重相对变化率会显著差于小管福寿螺(P0.05);当梨形环棱螺个体数少时(4只),其体重相对变化率与小管福寿螺无明显差异,但生存率会显著低于小管福寿螺(P 0.05)。间接分泌物干扰实验中,小管福寿螺的体重相对变化率极显著优于梨形环棱螺(P 0.01),且其生存率高于梨形环棱螺;在低密度组中,高比例(4只)的小管福寿螺生存率显著高于高比例(4只)的梨形环棱螺(P 0.05);而在高密度组中,高比例(8只)的梨形环棱螺在28d内全部死亡,由于对照组中即使是高密度的梨形环棱螺也拥有高生存率,说明这种效应不是梨形环棱螺本身所导致的,而是小管福寿螺的间接分泌物胁迫导致了梨形环棱螺的大量死亡。以上结果充分表明,小管福寿螺的间接分泌物干扰效应比直接生态挤压作用具有更严重的生态威胁性,且小管福寿螺的种内竞争调节能力优于梨形环棱螺,这可能是小管福寿螺作为入侵物种的一种有效生活史策略。     

五爪金龙乙醇提取物对福寿螺毒杀和水稻苗生长的影响

福寿螺和五爪金龙是两种危害严重的入侵生物,利用五爪金龙防治稻田福寿螺是以害治害的方法.盆栽条件下研究了五爪金龙乙醇提取物毒杀福寿螺的效果,以及其对水稻苗生长的影响.在砂培条件下五爪金龙乙醇提取物及其分离得到的甲醇相、乙酸乙酯相、乙醚相水溶液不仅对福寿螺起到毒杀作用, 而且对水稻秧苗生长有促进作用, 毒杀和促进作用由强到弱的顺序均为:乙醇提取物>甲醇相>乙酸乙酯相>乙醚相.在实验浓度范围内五爪金龙乙醇提物对福寿螺的毒杀效果及其对水稻苗促进作用强度均随浓度的增大而增强,在水稻土盆栽条件下抑制福寿螺取食水稻苗的效果与密达差异不显著(p>0.05).五爪金龙乙醇提取物能毒杀福寿螺,对水稻苗的生长没有不利的影响.因此, 利用五爪金龙防治稻田福寿螺危害是环境友好的非化学防治措施,具有良好的应用前景.     

Multitrophic influences on egg distribution in a specialized leaf beetle at multiple spatial scales

Egg distribution in herbivorous beetles can be affected by bottom-up (host plant), and by top-down factors (parasitoids and predators), as well as by other habitat parameters. The importance of bottom-up and top-down effects may change with spatial scale.

In this study, we investigated the influence of host plant factors and habitat structure on egg distribution in the leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae), a monophagous herbivore on Salvia pratensis L. (Lamiales: Lamiaceae), on four spatial scales: individual host plant, microhabitat, macrohabitat, and landscape. At the individual host plant scale we studied the correlation between egg clutch incidence and plant size and quality. On all other scales we analyzed the relationship between the egg clutch incidence of C. canaliculata and host plant percentage cover, host plant density, and the surrounding vegetation structure. Vegetation structure was examined as herbivores might escape egg parasitism by depositing their eggs on sites with vegetation factors unfavorable for host searching parasitoids.

The probability that egg clutches of C. canaliculata were present increased with an increasing size, percentage cover, and density of the host plant on three of the four spatial scales: individual host plant, microhabitat, and macrohabitat. There was no correlation between vegetation structure and egg clutch occurrence or parasitism on any spatial scale. A high percentage of egg clutches (38–56%) was parasitized by Foersterella reptans Nees (Hymenoptera: Tetracampidae), the only egg parasitoid, but there was no relationship between egg parasitism and the spatial distribution of egg clutches of C. canaliculata on any of the spatial scales investigated. However, we also discuss results from a further study, which revealed top-down effects on the larval stage.     

The biological control of Pomacea canaliculata population by rice-duck mutualism in paddy fields

Duck has been used as a non-chemical control method against Pomacea canaliculata Lamarck, but little is known about its principles that underlie the control of snail populations. An indoor experiment was initially used to observe the predation potential of ducks, followed by replicated field trials. In the indoor studies, ducks effectively preyed on juvenile snails, but had a weak predatory effect on large snails and egg clusters. In the field, application of a rice-duck mutualism system significantly reduced the numbers of snails (especially number of immature individuals), number of snail egg clusters and snail damage to rice plants. The controlling effect was longer and more stable than the chemical application, resulting in a better yield than with the pentachlorophenol sodium and tea seed powder treatment. Our experimental results also suggested that the snail age structure in the rice-duck mutualism plots was shifted towards older snails by ducks preying, indicating a trend towards population decline, and ducks caused snails to oviposit on sites not ideal for hatchling establishment. Throughout the studies, it is suggested that a rice-duck mutualism system could be used for controlling P. canaliculata in organic rice production.     

皂荚提取物的杀螺活性

[目的]研究皂荚生物农药活性,开发利用皂荚资源,发展环境友好的绿色植物源农药。[方法]采用室内生测和田间试验研究皂荚壳乙醇提取物的杀螺活性。[结果]皂荚提取物对福寿螺有显著的毒杀活性,对幼螺和成螺72 h的LC₅₀分别为40.56、109.83 mg·L^-1。田间试验表明,皂荚提取物对福寿螺有较好的防效,施用40 g·m^-2的皂荚提取物处理7 d后卵块减少率为100.00%（成螺失去产卵的能力）,防效为（99.12±1.26）%。[结论]皂荚提取物对福寿螺较好的生物防治效果,是一种潜在的生物杀螺剂。     

我国福寿螺入侵现状和防控研究进展

福寿螺原分布于南美洲,20世纪80年代作为一种水生经济生物引入我国,后因食味不佳被弃于水生环境,因其具有繁殖力高、适应性强、食性杂等特点,在我国多个区域迅速扩散入侵,已给农业生产、生态系统、人类健康等造成了严重的危害。文章对福寿螺入侵现状进行了深入分析与系统总结,介绍了现有福寿螺防控技术手段,重点阐述环境友好型福寿螺防控技术并对其进行了研究展望。目前,针对福寿螺防控实施的多种物理、化学和生物措施,治理效果不一,植物源生物控制技术因具有更高效、更经济、对非靶细胞更安全等优点,成为防治福寿螺的研究热点。然而此类研究多数集中于简单的毒杀效果试验,较少涉及毒杀机理、生殖系统等。本文旨在为全面了解我国福寿螺入侵现状、防控研究进展提供理论指导,为进一步探究福寿螺防控技术提供对策与新的思路。     

2种中草药对福寿螺的杀灭效果及对肝脏影响

【目的】有效控制福寿螺产生的危害,为实现中草药的资源化利用提供依据。【方法】以甘草、陈皮为植物源灭螺剂,进行不同浓度梯度(0、0.5、1.5、3.0、4.5、6.0 g·L^-1)提取液浸泡下的灭螺活性探究。【结果】甘草组、陈皮组处理下福寿螺死亡率随时间的增长在不同浓度下毒杀效果明显。对48 h时福寿螺死亡率数据进行概率单位法回归分析,发现甘草组(LC₂₅、LC₅₀、LC₇₅)<陈皮组(LC₂₅、LC₅₀、LC₇₅),说明福寿螺对甘草更敏感。为进一步探究福寿螺死亡原因,在前期研究的基础上深入探讨甘草、陈皮提取液对福寿螺的肝脏的影响,在亚致死浓度甘草0.511 g·L^-1 (LC₂₅)、0.940 g·L^-1 (LC₅₀)、1.727 g·L^-1 (LC₇₅)和陈皮3.892 g·L^-1 (LC₂₅)、4.863 g·L^-1 (LC₅₀)、6.076 g·L^-1 (LC₇₅)处理下对福寿螺肝脏进行扫描电镜观察,结果表明,相比对照组,处理组福寿螺肝脏组织表面干瘪,失去水分,受损严重时,质地松散,表面组织脱落。【结论】2种植物提取液均可以较好地灭杀福寿螺,且严重破坏福寿螺核心组织肝脏,甘草、陈皮可作为植物源灭螺剂进一步研究开发利用。