紫背金盘(Ajuga nipponensis)次生物质对桔全爪螨(Panonychus citri)的驱避作用

研究了紫背金盘Ajuga nipponensis Makino各溶剂提取物和部分化合物对桔全爪螨Panonychus citri McGregor雌成螨及其产卵的驱避作用.结果表明,石油醚萃取物、乙酸乙酯萃取物具有较强的生物活性.在0.1 g · L-1时, 石油醚和乙酸乙酯萃取物对该螨处理1d后的产卵忌避率分别为:84.86%、69.88%;2d后为89.49%、82.19%;对雌成螨驱避率分别为:85.08%、68.66%;2d后为50.96%、69.84%.乙酸乙酯萃取物经分离得到四类化合物,结果表明:馏分Ⅰ为长链脂肪酸混合物,具有较强生物活性,2000μg/ml和1000μg/ml处理1d后,产卵忌避率分别为:80.77%、74.77%;2d后为73.81%、72.59%.2000μg/ml处理1d后对雌成螨的驱避率为:69.88%;2d后为74.24%.刺槐素Ⅱ、新克罗烷化合物Ⅲ和β-蜕皮甾酮Ⅳ在2000μg/ml均不表现活性.对馏分Ⅰ中的4个主要化合物单体进行活性测定,结果表明:十六烷酸、十六烷酸甲酯、十六烷酸乙酯和十八烷酸甲酯在2000μg/ml处理时,1d后,产卵驱避率分别为:75.18%、61.76%、59.18%和66.49%;2d后产卵驱避率为:66.67%、31.15%、46.75%和44.84%;雌成螨驱避率分别为:1d后,67.53%、63.79%、59.26%和68.00;2d后,67.23%、43.96%、48.23%和64.19%.在1000μg/ml处理时,1d 后,产卵驱避率分别为:59.21%、59.16%、57.02%和61.40%;1d后,雌成螨驱避率分别为:69.64%、61.43%、55.76%和64.00%.     

水稻二化螟的交配行为

在室内条件下,对水稻二化螟Chilo suppressalis的交配行为及能力进行了研究.结果表明：大多数二化螟雌蛾一生只交配一次,平均0.92次;而雄蛾具有多次交配能力,最多达4次,平均2.72次.二化螟雌蛾的日龄影响其交配率、交配起始时间和持续时间,随二化螟雌蛾日龄的增加,其交配率逐渐下降,交配起始时间逐渐提前,而交配持续时间逐渐上升.相反,二化螟雄蛾日龄对其交配率、交配起始时间和持续时间没有明显影响.交配日龄对二化螟雌蛾的生殖力也存在显著影响,随着二化螟雌蛾交配日龄的增加,雌蛾产卵量下降,卵孵化率降低,产卵期缩短,它们都与雌蛾交配日龄存在显著的负相关;而雌蛾产卵前期和雌蛾寿命随雌蛾交配日龄的增加而延长,与雌蛾交配日龄存在显著的正相关.但二化螟雄蛾交配日龄对雌蛾的生殖力没有明显影响,二化螟雄蛾一生都具有较强的交配繁殖能力.同时,不同交配史的雄蛾与雌蛾交配,对雌蛾的生殖力也没有显著影响.表明二化螟的交配活动是由雌蛾主导控制的.最后,对这些结果在二化螟性信息素防治中应用的可行性进行了探讨.在应用性信息素控制二化螟的实践中,可以在两方面取得实效,一是性信息素可以阻碍雌雄之间正常交配,降低交配率;二是可以推迟二化螟雌虫的交配,使其产卵量和卵孵化率降低.     

栎黄枯叶蛾羽化及生殖行为研究

栎黄枯叶蛾Trabala vishnou gigantina Yang是近年在沙棘(Hippophae rhamnoides)林中大面积暴发的一种食叶害虫。通过野外调查和室内饲养观察相结合对该虫的羽化、交配和产卵等行为等进行了研究。结果表明,栎黄枯叶蛾羽化期40 d左右,羽化高峰期为9月上旬,日羽化高峰出现在傍晚17:00—23:00,占全天羽化量的82.46%;雌雄性比为1∶1.41;交配高峰期发生在凌晨3:00—4:00,成虫羽化翌日开始进行交尾,2日龄雌蛾交配率最高,达到45.6%,随后交配率逐步降低。雌蛾一生只交尾1次,雄蛾可进行多次交尾。成虫交配持续时间多为14¹6 h。成虫交配后即可产卵,产卵主要在夜间进行,产卵高峰期在2:00—6:00,占全天产卵量的82.40%。未交配雌蛾和雄蛾的平均寿命为11.05 d和9.85 d;显著高于已交配雌蛾和雄蛾的8.05 d和7.35 d,说明交配可明显缩短雌雄成虫寿命。     

六星黑点豹蠹蛾成虫生殖行为特征与性趋向

六星黑点豹蠹蛾Zeuzera leuconotum Butler (Lepidoptera: Cossidae)是一种重要的园林害虫。在光周期L:D=14:10、温度19-32 ℃、相对湿度75%-85%条件下,对六星黑点豹蠹蛾的羽化、性比、交配行为及能力进行了观察,利用风洞技术和林间诱蛾试验验证了其性趋向。结果表明:六星黑点豹蠹蛾羽化期60 d左右,6月下旬为羽化高峰期,日羽化高峰出现在傍晚17:00-18:00,占全天羽化量的55.4%;雌雄性比为1:1.03;交配高峰期发生在进入暗期5-7 h,成虫1日龄后性成熟,一生交配1次;随雌蛾日龄增加,其交配率逐渐下降,交配时间提前,交配持续时间逐渐加长;雌蛾一生平均产卵378个,孵化率80%,未交配雌蛾平均产卵426个,孵化率0%;未交配雌蛾和雄蛾的平均寿命分别为5.56 d和3.83 d,交配过的雌蛾和雄蛾平均寿命分别为5.66 d和2.41 d,交配缩短雄蛾寿命;六星黑点豹蠹蛾种内个体间引诱作用主要为雌蛾引诱雄蛾,同性间不存在聚集行为;2-3日龄未交配雌蛾林间诱蛾量最高,显著高于1日龄和4-6日龄(P＜0.01)。依据研究结果,分析讨论了应用性信息素防治六星黑点豹蠹蛾的可行性,说明六星黑点豹蠹蛾是可利用性信息素进行防控的理想对象。     

小菜蛾成虫对健康和机械损伤薄荷的嗅觉反应

【目的】比较健康和机械损伤的薄荷Mentha spicata对小菜蛾Plutella xylostella成虫嗅觉反应的影响,为筛选小菜蛾植物源驱避剂提供科学依据。【方法】利用触角电位(EAG)仪和Y型嗅觉仪分别测定小菜蛾雌、雄成虫对健康和机械损伤薄荷的触角电位和嗅觉行为反应,通过田间试验测定雌蛾产卵选择的忌避反应。【结果】健康薄荷和机械损伤薄荷均能引起小菜蛾雌、雄成虫触角电位反应,但损伤薄荷引起的触角电位反应值显著高于健康薄荷(P0.05);室内行为选择试验结果显示,损伤薄荷对小菜蛾雄性成虫有显著驱避作用(P0.05),驱避指数为53.33%,对雌性成虫有极显著驱避作用(P0.01),驱避指数达到80%;田间产卵选择试验发现,损伤薄荷对小菜蛾雌成虫产卵有极显著驱避作用(P0.01),产卵忌避指数达到71.32%。但是健康薄荷对小菜蛾雌、雄成虫的行为选择和雌性成虫的产卵选择均无显著驱避作用(P0.05)。【结论】机械损伤薄荷对小菜蛾成虫有较强的驱避效果,可以对其进行驱避活性挥发物质的筛选或作为驱避源来防治小菜蛾的危害。     

马铃薯块茎蛾的交配行为

在温度为(24±2)℃、光周期为L∶D=14∶10、相对湿度为50%～70%环境条件下观察了马铃薯块茎蛾Phthorimaea operculella(Zeller)交配行为。结果表明,1～2日龄、3～4日龄成虫交配高峰期分别发生在进入暗期后的8.0～10.0h、6.5～8.0h内。两性交配率随日龄的增加显著下降。马铃薯块茎蛾雄成虫具有多次交配能力,在连续发生2次以上行为交配时会导致雄蛾有效交配率下降。雄蛾平均有效交配次数可达3.8次/头,最高达6次。增加雄性比例不会显著提高单雌产卵量,但将性比(♀:♂)由1∶1升至2∶1时即可显著降低单雌产卵量。     

榆木蠹蛾生殖行为及性信息素产生与释放节律

通过室内饲养与野外观察榆木蠹蛾Holcocerus vicarius (Walker)成虫的羽化、交尾、产卵行为,触角电位反应测定处女雌蛾性信息素产生与释放节律,旨在为榆木蠹蛾性信息素的鉴定和合成奠定基础。结果表明：榆木蠹蛾羽化行为全天可见,主要集中在15:00－19:00。成虫羽化当日即可交尾,21:30－0:30进行婚飞和交尾,交尾高峰出现在晚23:00左右,光期未见交尾。随着日龄的增加,召唤时间前移并且延长,2～3日龄处女雌蛾召唤时间早于1日龄雌蛾,交尾时间较短;雌蛾在羽化1 d后达到性成熟,2日龄雌蛾交尾百分率最高,达41.8%。雌蛾将产卵器伸出寻找缝隙处产卵,分多处产卵,雌虫最高产卵量达720粒,最低产卵量为105粒,卵期为12～22 d不等,孵化率为72%～88%。羽化当晚的雌蛾体内性信息素含量较低,第2天最高,以后逐日下降;2日龄榆木蠹蛾处女雌蛾性信息素的产生量从晚17:00起逐渐增加, 21:30－22:00时最高, 22:00后逐渐减小。雄蛾触角电位反应在22:30最强。21:30－23:00是雌蛾产生和释放性信息素的高峰期。榆木蠹蛾的羽化、交尾存在一定的时辰节律,通过处女雌蛾的野外诱集试验证实了性信息素释放与交配行为在时辰节律上的一致性。     

山胡椒及其挥发物对马铃薯块茎蛾产卵选择的影响

【目的】为了确定山胡椒Lindera glauca(Sieb.Zuce)是否对马铃薯块茎蛾Phthorimaea operculella Zeller的产卵有驱避作用。【方法】利用选择性产卵试验方法在室内分别测定了山胡椒的完整果实、压碎果实、根以及不同浓度(0.25~4.0 g E/m L)的压碎山胡椒果实正己烷提取物对马铃薯块茎蛾产卵选择性的影响;在模拟仓库内测定了压碎的果实对其产卵的影响;进而在室内测定了柠檬醛、沉香醇、香叶醇和α-水芹烯不同浓度(0.00075~0.012 g/L)的溶液对其产卵选择性的影响。【结果】山胡椒完整果实、压碎果实、根在室内对马铃薯块茎蛾产卵具有驱避效果,其中压碎果实的产卵驱避效果最好,20 g压碎果实的产卵驱避率可达93.7%。山胡椒压碎果实正己烷提取物在0.5~4.0 g E/m L的浓度范围内随着浓度的升高,产卵驱避效果逐渐增强。在模拟仓库内20 g压碎的果实产卵驱避率是82.5%;0.003~0.012 g/L的柠檬醛,0.012 g/L沉香醇,0.00075~0.012 g/L的香叶醇,0.003~0.012 g/L的α-水芹烯对马铃薯块茎蛾产卵有显著的驱避效果。【结论】山胡椒及其挥发物对马铃薯块茎蛾产卵有驱避效果。     

杨小舟蛾的羽化和生殖行为节律

杨小舟蛾是近年来为害较严重的杨树食叶害虫之一.为探明该虫羽化及生殖行为的发生规律,为生态调控技术应用于其防治工作提供参考,本文在光周期L∶D=14∶10、温度(27±1)℃和相对湿度(60±10)%的条件下,研究了杨小舟蛾成虫的羽化、求偶、交配和产卵节律.结果表明:杨小舟蛾雌虫在蛹期7 d,雄虫在蛹期8 d达到羽化高峰;在昼夜24 h间,成虫的羽化主要集中在光期6 h至暗期2 h,雌虫羽化高峰期为光期11 h,雄虫较之晚1 h.雌蛾羽化后,只在暗期进行求偶,高峰期为暗期6~7 h;1~3 d雌蛾求偶率随日龄逐渐增加,3 d达69.8%,之后求偶率逐渐下降.在单对组中,雌、雄虫的交尾行为开始于暗期5 h,至暗期7~8 h达到高峰,而在多对组中,在暗期0.5 h就已出现交尾行为,高峰期较单对组晚1.5 h.1~3 d雌蛾产卵量占其总产卵量的68.4%,之后逐渐减少.     

黄地老虎幼虫取食诱导的棉花植株挥发物驱避雌蛾产卵

[目的]评价黄地老虎Agrotis segetum幼虫取食危害诱导棉花植株产生的虫害诱导植物挥发物(herbivore-induced plant volatiles,HIPVs)对雌蛾产卵选择的影响,并鉴定HIPVs的主要组分及其功能,以筛选对雌蛾产卵有吸引或驱避作用的活性成分.[方法]利用气相色谱-质谱联用仪(GC...     

Preimaginal conditioning does not affect oviposition preference in the diamondback moth

Abstract.  1. In holometabolous insects, learning has been demonstrated in both larval and adult stages. Whether learning can be retained through metamorphosis from larva via pupa to adult has long been a subject of debate. The present study is designed to distinguish between preimaginal and imaginal conditioning in the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae) using oviposition preference tests on females exposed to various types of learning experiences during immature and adult stages.
2. Cohorts of test insects were reared from egg to pupa on an artificial diet, or on one of two host plants, Chinese cabbage, Brassica campestris L. ssp. pekinensis , and common cabbage, Brassica oleracea L. var. capitata . The ensuing females reared on the three kinds of food showed similar oviposition preference between the two plants. A brief experience of the less preferred host, common cabbage, by adults slightly increased their preference for this plant.
3. Cohorts of test insects were reared from egg to pupa on an artificial diet with or without the addition of a neem-based oviposition deterrent (Neemix^® 4.5). Larval feeding experience did not alter oviposition response to the deterrent. However, emergence conditioning and early adult learning, achieved through experience of a residue of the deterrent carried over from the larval food on pupal cuticle and cocoons, altered oviposition preference significantly.
4. The combined results revealed no evidence of preimaginal conditioning in this insect but a strong effect of emergence conditioning and early adult learning on oviposition preference.     

颜色对苹果蠹蛾产卵选择性的影响

苹果蠹蛾Cydia pomonella Linne是为害苹果Malus pumila Mill.、梨Pyrus spp.、桃Amygdalus persica L.等仁果类和核果类果树的重要蛀果害虫之一.为明确寄主颜色在苹果蠹蛾产卵中的作用,本文研究了不同颜色对苹果蠹蛾雌成虫产卵选择性的影响.试验采用彩色硫酸纸模拟寄主...     

Oviposition preference of Lygocoris pabulinus (Het., Miridae) in relation to plants and conspecifics

Abstract: To predict possible locations of Lygocoris pabulinus (L) in the field during the summer, we determined their oviposition preference under summer conditions. With L. pabulinus reared on potato, oviposition preference was determined for potato, tomato or green bean. As preference may depend on larval or early adult experience, the oviposition preference of bugs reared on green bean for three generations, and of bugs captured from the field 12 h prior to the experiment was also determined. All females showed a strong preference for potato plants, on which fecundity was higher. Hence, although L. pabulinus is a generalist in its feeding habits, the summer generation seems to be an oviposition specialist. Aggregation of ovipositing females does not seem to occur; similar amounts of eggs were oviposited in plants with clip cages containing conspecifics as in plants without conspecifics. More eggs were oviposited in damaged plants than in undamaged plants. Plant volatiles released upon damage may aid L. pabulinus females in finding suitable oviposition sites.     

甜菜夜蛾对不同寄主植物的产卵和取食选择

为了探讨甜菜夜蛾Spodoptera exigua对不同寄主植物的产卵选择及成虫产卵选择与幼虫取食选择间的关联度, 本研究选取玉米、豇豆、甘蓝、黄瓜、棉花、辣椒和番茄7种植物进行了选择性和非选择性实验研究, 并采用Y型嗅觉仪测定了成虫对其中3种寄主植物及其挥发物抽提物的趋性。结果表明：在田间非选择性实验中, 甜菜夜蛾在不同寄主植物上的落卵量依次为：玉米>辣椒>棉花>黄瓜、豇豆、番茄>甘蓝。Y型嗅觉仪的行为测定表明, 雌成虫对玉米及其挥发物抽提物的趋性最强, 黄瓜次之, 对甘蓝的趋性最弱, 这与雌虫的产卵选择性一致。不同龄期甜菜夜蛾幼虫对寄主植物的取食选择性有所不同, 且随观测时间的延长有所改变;低龄幼虫对豇豆、玉米和黄瓜的选择性较强, 对甘蓝、番茄、辣椒和棉花的取食选择性则较弱, 高龄幼虫对辣椒也具有较强的选择性;5龄幼虫对寄主植物的选择性不如低龄幼虫明显。结果显示, 甜菜夜蛾对不同寄主植物的产卵选择性显著不同, 植物抽提物在雌成虫的产卵选择中具有重要作用, 甜菜夜蛾对寄主植物的产卵选择性和幼虫取食选择性并不一致。     

Effects of natal habitat odour, reinforced by adult experience, on choice of oviposition site in the mosquito Aedes aegypti

The effects of natal experience on the oviposition behaviour of adult female mosquitoes were investigated in the laboratory using Aedes aegypti (L.) (Diptera: Culicidae). 'Treatment' mosquitoes were exposed to a dilute repellent (inducing stimulus) in their breeding water (aquatic stages) and/or in the air (adults) during various combinations of life stages [larval only (L regime); larval and pupal (LP regime); larval, pupal and emergent adult (LPE regime); larval, pupal, emergent adult and adult (LPEA regime); pupal, emergent adult and adult (PEA regime); adult only (A regime)]. 'Control' mosquitoes were raised in an identical manner, but were not exposed to the inducing stimulus. The oviposition behaviour of treatment and control females was assessed in an oviposition assay that presented a choice of water with or without the inducing stimulus. Of the 435 mosquitoes tested in the experiment, 176 were non-distributors (i.e. laid all of their eggs in only one of the choices). Treatment females (distributors plus non-distributors) reared in the presence of the inducing stimulus throughout their lives (LPEA regime) showed a significant preference for the oviposition option containing the inducing stimulus (24/36 females) compared with corresponding controls (5/39 females). Distributors reared under the LPEA and PEA regimes also showed this preference (6/6 treatment vs. 2/29 control females, and 13/18 treatment vs. 7/23 control females, respectively). Females that had been exposed to the inducing stimulus as either immatures or adults only showed no preference for, and some showed an aversion to, the treatment oviposition option. This is interpreted as evidence for a natal habitat preference induction (NHPI) in this species, albeit one that requires extensive reinforcement in the adult stage. This adult experience-reinforced NHPI (AER-NHPI) is discussed in terms of its adaptive significance for container breeders, the possible timing mechanism and sensory basis of induction and potential practical consequences.     

Experience‐ and age‐mediated oviposition behaviour in the yellow fever mosquito Stegomyia aegypti (=Aedes aegypti)

In repeated behaviours such as those of feeding and reproduction, past experiences can inform future behaviour. By altering their behaviour in response to environmental stimuli, insects in highly variable landscapes can tailor their behaviour to their particular environment. In particular, female mosquitoes may benefit from plasticity in their choice of egg‐laying site as these sites are often temporally variable and clustered. The opportunity to adapt egg‐laying behaviour to past experience also exists for mosquito populations as females typically lay eggs multiple times throughout their lives. Whether experience and age affect egg‐laying (or oviposition) behaviour in the mosquito Stegomyia aegypti (=Aedes aegypti) (Diptera: Culicidae) was assessed using a wind tunnel. Initially, gravid mosquitoes were provided with a cup containing either repellent or well water. After ovipositing in these cups, the mosquitoes were blood‐fed and introduced into a wind tunnel. In this wind tunnel, an oviposition cup containing repellent was placed in the immediate vicinity of the gravid mosquitoes. A cup containing well water was placed at the opposite end of the tunnel so that if the females flew across the chamber, they encountered the well water cup, in which they readily laid eggs. Mosquitoes previously exposed to repellent cups became significantly more likely to later lay eggs in repellent cups, suggesting that previous experience with suboptimal oviposition sites informs mosquitoes of the characteristics of nearby oviposition sites. These results provide further evidence that mosquitoes modify behaviour in response to environmental information and are demonstrated in a vector species in which behavioural plasticity may be ecologically and epidemiologically meaningful.     

Effect of Delayed Mating on Oviposition Pattern, Fecundity and Fertility in Codling Moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae)

Female codling moth ( Cydia pomonella ) were mated either on the day of emergence or 2 or 4 d after emergence. Oviposition was checked daily and fertility (% egg hatch) of eggs laid 1–4 d and 5 + d after mating was determined from a sub-sample of females in each treatment. From these data, net reproduction rate (R₀) was calculated. the effect of delayed mating of males was also determined. Mean fecundity, fertility and net reproduction rate of females mated 4 d after emergence were significantly lower than for females mated either on the day of emergence (day 0) or 2 d after emergence. There were no significant differences between the three treatments in terms of the proportion of females that mated or female longevity, although there was a trend towards increased longevity with increasing delays in mating. Mean longevity of unmated females was significantly greater than that of mated females. Oviposition pattern was similar in females regardless of when they were mated and in all cases maximum oviposition took place 2 d after mating. There was no effect on the fecundity of 2 d old females or on the fertility of their eggs when they were paired with either 2 or 6 d old males. the significance of these findings in relation to control of codling moth by mating disruption is discussed.     

Oviposition deterrence of shoots and essential oils of Minthostachys spp. (Lamiaceae) against the potato tuber moth

Abstract:  The potato tuber moth is a noxious pest of potato in stores, where the use of repellent plants is an environmentally sound alternative to the application of chemical pesticides. We evaluated the protective effect of native Minthostachys species (Lamiaceae) against tuber infestation by the potato tuber moth in a rustic store in Cusco, Perú. We covered potato tubers with dried shoots of Minthostachys spicata and Minthostachys glabrescens and compared tuber damage with a control treatment of maize straw. We also conducted a no-choice oviposition bioassay in the laboratory, testing the oviposition deterrence of essential oils of M. spicata , M. glabrescens and Minthostachys mollis at natural concentrations. We recorded the number of eggs laid by mated moths on filter paper treated with essential oils of each of the three species and on two control treatments: hexane and untreated blank. Finally, we tested for differences in oviposition deterrence among five full-sib families of potato tuber moth raised under identical conditions. We found that dried, chopped leaves and flowers of Minthostachys species reduced the percentage of tuber damage in stores in comparison with the control (5% vs. 12%), but no difference in protection was found between species. Essential oils at natural concentrations deterred moth oviposition, reducing the number of eggs laid by about 80% compared with the control treatments; again, there were no significant differences between Minthostachys species. Finally, whereas we detected among-family variation in oviposition on filter papers treated with essential oils, no difference was found in the number of eggs laid on control substrates. Therefore, there was genetic variation for oviposition deterrence in the potato tuber moth and resistance to repellent plants might evolve thereafter.     

Seasonal and cultivar-associated variation in oviposition preference of Oriental fruit moth (Lepidoptera: Tortricidae) adults and feeding behavior of neonate larvae in apples

The Oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae) has become a pest of tree fruits since its introduction to the United States in the early twentieth century. Oriental fruit moth has historically been a major pest problem in peach production, and outbreaks in commercial apple (Malus spp.) orchards in the eastern United States were rare until the late 1990s. Recent outbreaks in Mid-Atlantic apple orchards have lead researchers to investigate host-associated effects on oriental fruit moth biology, behavior, and population dynamics. Studies were designed to assess cultivar level effects in apples on oviposition and larval feeding behavior of oriental fruit moth. In a mixed cultivar apple orchard, total oriental fruit moth oviposition and oviposition site preferences varied between cultivars. These preferences also varied over time, when sampling was repeated at various times of the growing season. Although most adult female oriental fruit moth preferentially oviposited in the calyx and stem areas of apple fruit, noticeable numbers of eggs also were laid on the sides of fruit, contradicting some previous reports. Oriental fruit moth females exhibited a strong ovipositional preference for fruit that were previously damaged by oriental fruit moth or codling moth, Cydia ponmonella (L.). The majority of newly hatched oriental fruit moth larvae were observed to spend <24 h on the surface of apple fruit before entry, and this behavior was observed on several apple cultivars. Neonate larvae exhibited a preference for entering fruit at either the stem or calyx ends, regardless of their initial site of placement. Our findings underscore the importance of adequate spray coverage and accurate timing of insecticide applications targeting oriental fruit moth.     

The role of pre- and post-imaginal experience in the host-finding and oviposition behaviour of the cabbage moth

The influence of pre- and post-imaginal experience on the orientation, landing, and oviposition of the female cabbage moth, Mamestra brassicae (L.) (Lepidoptera: Noctuidae) was studied in a wind tunnel. The results of experiments on the influence of pre-imaginal experience do not support the Hopkins host selection hypothesis because the females’ responses to host plants were not affected by the plant species used for feeding the larvae. The females were initially attracted to and landed on chrysanthemum whether or not they were fed on this plant species. In addition, the oviposition preference for cabbage plants was not changed by the larval feeding regimen. Imaginal experience influenced the females’ subsequent orientation/landing responses: exposure of the females to chrysanthemum plants for 5 min decreased their subsequent responses to this species, but subsequent responses to cabbage were not changed when the females were exposed to cabbage plants. Overnight exposure of females to a chrysanthemum or cabbage plant decreased the subsequent orientation/landing on the same species offered in non-choice tests. A similar effect was observed in responses to chrysanthemum plants after overnight contact, and possibly to cabbage plants, in the two-choice tests. Overnight exposure to cabbage or chrysanthemum had no effect on subsequent oviposition: females from both treatments oviposited more often on cabbage.