Return migration of Helicoverpa armigera (Lepidoptera: Noctuidae) during autumn in northern China

The autumn migration of Helicoverpa armigera (Hübner) was observed with radar and two types of light-trap at Langfang, Hebei province, China in 2001 and 2002. The sudden increase in the proportion of H. armigera moths in the searchlight trap indicated migration into the area and catches increased 10-fold during the second half of the night due to the landing of migrants before dawn. The moths' migratory flights took place at up to 2000 m above the ground, and moths flew differentially at times, and heights, when favourable (i.e. northerly) winds occurred. This facilitated the maximum displacement of moths towards the south during these 'return' migrations. The moths flew over the radar site at consistently high densities through the night, and the resulting flight durations of c. 10 h, at displacement speeds of 30-33 km h-1, would allow moths emerging in the far northeast of China (i.e. Liaoning and Jilin provinces and the Inner Mongolia autonomous region) to migrate into northern China (Hebei, Shandong and Henan provinces). The association of the seasonal migratory movements of H. armigera with crops in northern China is briefly discussed.     

Radar observations of the autumn migration of the beet armyworm Spodoptera exigua (Lepidoptera: Noctuidae) and other moths in northern China

The autumn return migration of the beet armyworm Spodoptera exigua Hübner and other insects in northern China was observed with radar and with a simultaneously-operated searchlight trap and ground light-trap at a site in Langfang, near Beijing. The searchlight trap was found to be an efficient tool for trapping migrants and, operated alongside a ground light-trap, could distinguish migrant from locally-flying species. It was confirmed that S. exigua and some other species were high-altitude nocturnal windborne migrants during September and October in northern China. Maximum density of moths typically occurred below 500 m, and strong layering was often observed at about 200 m above ground level in airflows that would carry the moths towards the south. Descent of S. exigua in the vicinity of the radar site in late September was often associated with rain.     

东北地区粘虫的季节性迁飞行为(英文)

粘虫Mythimna separata是我国农业生产上的重要害虫, 为了明确其季节性迁飞行为参数, 本研究采用垂直监测昆虫雷达（vertical-looking radar, VLR）及相关辅助设备的长期自动观测, 结合基于GIS的大区环流和轨迹模拟, 调查分析了2005年东北地区粘虫季节性迁飞行为。结果表明： 粘虫在不同季节和夜间不同时间空中飞行高度具有明显差异, 空中飞行行为受气象条件尤其是空中风场影响较大; 春季和秋季主要借助气流运载进行大规模长距离迁飞, 夜间持续飞行时间可达9 h, 多数个体能完成整夜飞行, 春季迁飞高度主要在300~600 m, 秋季飞行高度相对较低主要在300 m以下和400~500 m。夏季雷达回波有明显的成层现象, 最高可达1 000 m, 主要集中在500 m和700 m两个高度层。轨迹分析显示： 5月29日由山东潍坊、 临沂等虫源地起飞的黏虫, 顺西南气流越海迁飞, 6月1日在气旋天气影响下, 在吉林省白城等地降落; 7月中旬主要为当地黏虫受对流天气影响进行短距离迁飞扩散; 9月11日虫源来自内蒙古呼伦贝尔, 顺西北气流向吉林省东南方向迁飞。研究结果为东北地区粘虫的有效防控提供了技术支撑。     

Nocturnal migration of dragonflies over the Bohai Sea in northern China

Abstract.  1. A sudden increase and subsequent sharp decrease of catches of dragonflies in a searchlight trap, with Pantala flavescens Fabricius (Odonata: Libellulidae) predominating, observed at Beihuang Island in the centre of the Bohai Gulf, in 2003 and 2004, indicated a seasonal migration of these insects over the sea during the night in China. The movements were associated with the onset of fog.
2. Simultaneous radar observations indicated that the nocturnally migrating dragonflies generally flew at altitudes of up to 1000 m above sea level, with high density concentrations at about 200–300 or 500 m; these concentrations were coincident with the temperature inversion.
3. During early summer, the dragonflies oriented in a downwind direction, so that the displacement direction varied between different altitudes. In contrast, during late summer, the dragonflies were able to compensate for wind drift, even headwind drift, so as to orient south-westward no matter how the wind changed, and thus the displacement direction was towards the south-west.
4. The duration of flight, estimated from the variation of area density derived from radar data and hourly catches in the searchlight trap through the night, was about 9–10 h. The displacement speed detected using radar was ≈5–11 m s⁻¹. Therefore, the dragonflies might migrate 150–400 km in a single flight.
5. The dragonflies were thought to originate in Jiangsu province and they migrated into north-east China to exploit the temporary environment of paddy fields in early summer. Their offspring probably migrated back south during late summer and autumn.     

Radar observations of the spring migration into northeastern China of the oriental armyworm moth, Mythimna separata, and other insects

Abstract. 1. The spring migration of the oriental armyworm moth, Mythimna separata (Walker), and other insects into northeastern China was observed by radar at a site in central Jilin province. Samples of the migrants were obtained in a net flown from a kite, and M.separata populations in the surrounding region were monitored with a trap network. 2. The radar regularly detected echoes which were of the type characteristic of large insects, and three out of four large insects in the aerial samples were noctuid moths, including one M.separata. Catches of armyworm moths in the regional trap network peaked during the period of radar observations. 3. Migration occurred at night. It commenced with a take-off flight at dusk and generally continued until dawn, with numbers often being highest around midnight. Most migration took place at altitudes below 500 m, with strong layer concentrations forming at 200–400 m during the middle part of some nights. 4. Migration was approximately downwind. The net movement was overwhelmingly to the northeast because southwesterly winds occurred most frequently and were relatively strong, and because migration was more intense and prolonged on these winds. Orientation tended to be to the left of the downwind direction, and was most often to the north or northeast. 5. Migration into northeastern China was accomplished in a series of night-time movements of 100–300 km rather than by a single non-stop flight. 6. The net movement of insects towards the northeast was sufficient to produce the observed regional infestation of M.separata moths. Oviposition by immigrant armyworm moths in vulnerable crops would have been at a level where economically significant damage would be expected from the resulting larval population. 7. Analogous springtime migrations of noctuids leading to temporary colonizations of habitats at higher latitudes occur in other continents. Such colonizations may be unproductive if, as appears possibly the case for northeastern China, prevailing winds later in the season are generally unfavourable for a return migration towards overwintering areas at lower latitudes.     

褐飞虱2009年秋季回迁的雷达监测及轨迹分析

褐飞虱Nilaparvata lugens (Stål)是水稻生产上重要的迁飞性害虫,研究其迁飞、扩散规律,为早期预警和有效防治提供科学依据。2009年4月27日至10月11日, 在中国农业科学院植物保护研究所重大病虫害监测预警兴安雷达站内利用毫米波扫描昆虫雷达对褐飞虱的迁飞过程进行长期观测,高空探照灯诱虫器及佳多自动虫情测报灯诱虫器分别用来诱捕高空及地面的褐飞虱,对高空探照灯诱到的褐飞虱雌成虫随机挑选30头进行卵巢解剖, 并结合大区环流和利用Hysplit_4模型进行轨迹分析,研究了褐飞虱的秋季回迁过程和虫源。结果表明：褐飞虱秋季回迁高峰期出现在9月28日至10月7日,高峰日为10月1日, 高峰日内雷达回波主要在600~1 100 m范围内聚集成层,高空探照灯诱虫器内褐飞虱的数量达到了13 620头;卵巢发育级别以1~2级为主。轨迹分析显示：本次回迁的褐飞虱主要来自湖南衡阳和永州等地,随东北气流向广西柳州、南宁和崇左等方向迁飞。轨迹推断与褐飞虱实发虫情基本吻合,通过毫米波扫描昆虫雷达确定了褐飞虱秋季回迁的高度,为毫米波扫描昆虫雷达早期投入到预测预报的实践中奠定了基础,对我国褐飞虱早期预警体系的建立将提供必要的技术支持。     

2002年我国华北三代粘虫大发生的虫源分析

华北平原地区三代粘虫的大发生是一小概率事件,对其虫源问题尚无确切回答.应用HYSPLIT 4.8轨迹分析平台对2002年华北平原地区三代粘虫主要迁入峰期进行轨迹回推以确定此次迁入的虫源区,同时对东北地区虫源在迁出期的去向进行了模拟;并运用GrADS气象图形软件对华北地区和东北地区迁飞期天气学背景和风场的时空分布进行了分析.结果表明:2002年华北平原地区大发生的三代粘虫主要虫源来自陕西、山西二省;东北地区虫源对本次华北平原地区的迁入无影响.     

The role of nectar plants in severe outbreaks of armyworm Mythimna separata (Lepidoptera: Noctuidae) in China

The period from March to mid April, when oriental armyworm Mythimna separata (Walker) moths migrate from South China to Central China over several nights, is an important window of time in annual armyworm population increase. The presence of nectar sources along the pathway of the migratory population is a prerequisite for moths to reach target habitats and lay eggs. Using flowering periods and geographic distributions, the major spring nectar plants suitable for M. separata moths were identified from among 102 species/varieties of apicultural nectar plants. The nectar plants proposed as important to M. separata include milk vetch Astragalus sinicus L., rape Brassica napa L. and six other species. Spearman's rank correlation analyses were conducted between the annual population size of M. separata and the acreages of milk vetch and rape in the daily stopover areas for migrating populations of M. separata during 1950-1979. The Spearman's coefficient between milk vetch and M. separata was 0.6259 and the correlation was highly significant (P<0.001). Further regression analysis with data from 1950-1979 and from 1980-1992 also revealed a close relationship between annual acreage of damaged crops/wheat and acreage of milk vetch. These results strongly suggest that the unprecedented enlargement in the geographic distribution of milk vetch from Central China into South China was the key factor in the frequent severe oriental armyworm outbreaks that occurred during 1966-1977. This is thought to be the first report in the world that reveals the key role of nectar sources in long distance, regional scale, migration of moths. The argument for the key role of milk vetch is supported by the simultaneous decline in the level of damage inflicted by M. separata and the acreage of milk vetch after 1980.     

Is Mythimna turca (Lepidoptera: Noctuidae) a migrant?

The double line moth, Mythimna turca (Linnaeus, 1761) (Lepidoptera: Noctuidae), is an important widely distributed insect species. Studies on the moth in European countries have focused on population monitoring and in China on taxonomy of Mythimna and distribution surveys of M. turca. However, whether M. turca is a migratory insect is unknown. Here, migration of the moth population was monitored using a searchlight trap from 2004 to 2020 on Beihuang island, Northern China, providing direct evidence that M. turca migrates across the Bohai Strait seasonally, in late May to early September. Population dynamics, ovarian development, wind direction and possible migration trajectories were also analyzed. Most moths migrated in June and at the end of August and the beginning of September, and a few migrated in May, July and October. The average duration of this windborne migratory period of M. turca was 93 d. Migratory trajectories demonstrated that M. turca mainly moved northward in spells of southerly winds from June to August and moved southward in spells of northerly winds during September. This new key information about the ecology of M. turca population will aid the formulation of M. turca management strategies.     

草地螟2007年越冬代成虫迁飞行为研究与虫源分析

草地螟 Loxostege sticticalis L.是危害我国北方农牧业的一种重要迁飞性害虫,明确草地螟的虫源地及迁飞路线对其早期预警具有重要意义。本文利用垂直监测昆虫雷达的长期观测,迁飞高峰期雌虫卵巢解剖、大区环流分析、各地虫情信息收集和利用Hysplit_4模型进行轨迹分析,研究了2007年越冬代草地螟的空中迁飞行为和东北地区严重暴发的草地螟虫源。结果表明：6月7–9日,雷达观测点诱虫灯内草地螟具有典型迁飞昆虫生理特征;草地螟主要在夜间迁飞,飞行高度集中在300～500 m,400 m是主要飞行高度,迁飞高峰期夜间迁移可持续9 h。东北地区严重发生的草地螟虫源,一部分来自内蒙古乌盟地区,一部分来自蒙古共和国中东部及中俄边境地区。据此推测我国与国外草地螟存在虫源交流。     

Does the onset of sexual maturation terminate the expression of migratory behaviour in moths? A study of the oriental armyworm, Mythimna separata

It is generally accepted that in most insects adults are sexually immature when they initiate migration and that migratory behaviour terminates with the onset of sexual maturation. However, a few studies examining the mating status of field collected moths have suggested that sexually mature individuals may continue migrating, but in these cases it was impossible to completely eliminate the possibility that the mated females captured came from local, non-migrant populations. In this study we examined the ovarian development of Mythimna separata females captured using a vertical pointing searchlight trap on Beihuang Island in the Bohai Gulf, China, a site >40 km from land. Moths were collected from May to October from 2003 to 2008 in order to test the hypothesis that the onset of sexual maturation resulted in the termination of migratory behaviour. While females at the end of the summer had little ovarian development and were unmated, a significant proportion of those migrating northward in the early summer had developed ovaries and often had at least one spermatophore. Given that theses insects were captured while flying up to 500 m above sea level, at a site with no local populations, the findings would not support the hypothesis and suggest that both ovarian development and mating may occur during migration.     

雷达观测空中飞行昆虫的有效距离

以包覆细铜纱网的乒乓球作为标准检测目标,检测了X-频带,波长3cm的公主岭昆虫雷达观测空中飞行昆虫的有效距离。检测到乒乓球回波的最远距离为5185.6m;计算观测个体粘虫Mythimnaseparata（Walker）的最远有效距离约为2000m,观测个体褐飞虱Nilaparvatalugens（Stal）的最远有效距离的为300m。该雷达适于观测粘虫等体重几十mg的昆虫在空中的飞行动态。     

东方白鹳幼鸟渤海湾越冬群体的迁徙策略

东方白鹳(Ciconia boyciana)主要在俄罗斯远东和中国东北繁殖, 在中国主要有两个越冬群体(长江越冬群体, 迁徙距离约2,600 km; 渤海湾越冬群体, 迁徙距离约1,500 km)。本文基于2016-2018年的卫星追踪数据(N = 14), 分析了渤海湾越冬群体幼鸟春季和秋季的迁徙策略和利用风的方式, 总结了850 mb压力下风速和风向对日迁徙飞行速度的影响。该群体春秋两季迁徙距离相似, 但春季的顺风条件(2.2 ± 6.3 m/s)显著优于秋季的逆风条件(-2.4 ± 4.1 m/s, P < 0.05), 这使得春季迁徙飞行速度(280.4 ± 62.0 km/d)显著快于秋季(185.5 ± 72.0 km/d, P < 0.05), 春季迁徙飞行时间(5.9 ± 2.5 d)显著短于秋季(10.3 ± 6.5 d, P < 0.05); 同时, 春季停歇时间(5.4 ± 9.7 d)短于秋季(17.8 ± 18.2 d, P = 0.05)。基于以上原因, 东方白鹳春季迁徙持续时间(11.2 ± 8.7 d)显著短于秋季(28.0 ± 21.2 d, P < 0.05)。渤海湾越冬群体幼鸟迁徙时, 春季利用顺风更快到达度夏地, 秋季逆风迁徙, 迁徙飞行速度慢, 迁徙飞行时间和停歇时间长。因此, 东方白鹳迁徙时虽然主要利用上升热气流翱翔, 但顺风也是其成功迁徙的有利因素。     

Annual Migration of Agrotis segetum (Lepidoptera: Noctuidae): Observed on a Small Isolated Island in Northern China

Migration behavior of the turnip moth, Agrotis segetum (Lepidoptera: Noctuidae), is not well known by far. Here, we present the data from an 11-year study on A. segetum by means of searchlight trapping and ovarian dissection on Beihuang (BH) Island, which located in the center of the Bohai Strait in northern China. The data showed a large number of A. segetum flight across the strait each year, which provides direct evidence that A. segetum is a long-distance migrant, migrating at least 40 - 60 km to reach the trapping site. The migration period during 2003-2013 ranged from 115 to 172 d. Among the catches, the proportion of females was significantly higher than that of males in each month from May to September. Ovarian dissection showed that the proportion of mated females and the proportion of sexually mature females was significantly higher than that of unmated females and sexually immature females in early summer, respectively, but conversely in autumn. The early summer populations migrate in a south-north direction, which might undertake a long-distance flight on several successive nights. The autumn populations migrate in a north-south direction, which might originate not far from the trapping site. Based on these findings, the migratory physiology of A. segetum was discussed.     

粘虫下唇须陷窝器及其感器的形态、类型与分布

【目的】明确我国重要农业害虫粘虫Mythimna separata Walker下唇须和陷窝器形态结构以及陷窝器内部感器的形态、类型与分布。【方法】利用光学显微镜观察粘虫成虫下唇须及陷窝器形态结构,利用扫描电子显微镜观察陷窝器内部的感器。【结果】结果表明,粘虫成虫下唇须似管状,具3节,各节形态和长度不同,其中第2节最长。粘虫下唇须长度雌雄异形,雌性的下唇须长度为2 463.50±143.65 μm,显著短于雄性的（2 566.11±70.28 μm）（t=2.722, df=34, P=0.012）。陷窝器凹坑深约280 μm,开口处直径约50 μm,内部直径约32 μm,雌雄间无显著差异。陷窝器内部的感器主要包括毛形感器和棒状感器2种类型。毛形感器位于陷窝器凹坑的上半部分,而棒状感器分布在陷窝器凹坑的下半部分。雌性毛形感器长为18.20±0.84 μm,显著短于雄性的21.24±0.34 μm（t=3.335, df=30, P=0.003）。而雌性的棒状感器长为14.69±0.48 μm,显著长于雄性的12.31±0.49 μm（t=3.452, df=21, P=0.002）。【结论】粘虫下唇须陷窝器感器分属2大类型,分布于陷窝器内不同的区域,其长度具有性别差异性。本文报道的这些形态学观察结果为进一步研究粘虫下唇须陷窝器感器生理和功能奠定了基础。     

10. PROCEEDINGS OF THE SEVENTEENTH ANNUAL GENERAL MEETING OF THE S.A. ORNITHOLOGICAL SOCIETY HELD IN THE COMMITTEE ROOM OF THE PUBLIC LIBRARY. JOHANNESBURG,AT 3 P.M., SATURDAY, 8TH MARCH. 1947

Bruderer, B. 1994. Nocturnal bud migration in the Negev (Israel) a tracking radar study. Ostrich 65: 204–212.

The present publication summarizes the methodological possibilities of tracking radar and describes some features of nocturnal migration at two sites in the Negev, which include anwers to basic questions of bird migration. The directions of spring and autumn migration were practically opposite; only the headings in spring indicated some more compensation for stronger westerly winds. The volume of nocturnal spring migration was only about 65% of autumn migration, which may be an indication of mortality outside tie breeding area. Highest densities of migration at the two radar sites in the Negev Highlands (450 m above sea level) and in the Arava Valley (150 m below sea level) indicated flightlevels adjusted to atmospheric conditions aloft, and not to round level. Due to the trade-wind system, the birds heading southward in autumn flew mainly below flew mainly above 1500 m above sea level, while in spring they tended to make use of the anti-trades at higher altitudes. The decisive factor for altitude choice was the speed of tailwind in spring and autumn; other factors, such as temperature, humidity and pressure had no significant influence on the altitude distributions. With respect to the question of non-stop or intermittent flight across large desert areas, the data show that between the eastern deserts of Egypt and the Sinai/Negev complex the nocturnal migrants maintained their schedule of nocturnal flight and diurnal rest. A few exceptions of nocturnal migrants continuing migration at high altitudes into the day were identified mainly as heron- and gull-type birds. The proportion of waders and waterfowl identified by wing-beat pattern in nocturnal migration is nearly the same at both sites, indicating broad-front migration across the desert. The numbers of birds with continuous wingbeats is, however, so large compared to available estimates of waders and waterfowl wintering in Africa that careful reconsideration of the underlying assumptions in the radar and field estimates is necessary.     

东海普通波水蚤种群特征与环境关系研究

根据1997～2000年东海23°30′～33°N、118°30′～128°E海域4个季节海洋调查资料,对东海浮游桡足类普通波水蚤(Undinula vulgaris)自然种群特征与环境的关系进行研究,并与1979～1980年资料进行比较.结果表明,普通波水蚤优势度、平均丰度、出现频率和占浮游桡足类总丰度的百分比均有显著的季节变化,其中秋季分别为0.09、556 ind·100 m^-3、93.69％和9.90％,夏季为0.03、86 ind·100 m^-3、68.49％和4.08％,冬季为0.02、42 ind·100 m^-3、53.85％和3.80％,春季为0.01、16 ind·100 m^-3、34.35％和2.31％.普通波水蚤在东海的优势性主要表现在秋季.与20年前同海域研究结果相比,近年春、夏和秋3季普通波水蚤在东海浮游桡足类中的重要性有所降低,而冬季有所增加.冬季的增加可能与全球气候变暖相关.底层水环境变化是影响普通波水蚤种群数量分布的主要因子,说明该种数量变化与暖流势力有密切关系.普通波水蚤对沿岸水团和低温环境敏感,其高丰度分布区是暖流位置的良好指示.作为秋季东海重要的桡足类浮游动物,普通波水蚤在东海海洋渔业中有重要意义.     

变温对粘虫生殖及主要能源物质代谢的影响

【目的】明确变温与粘虫Mythimna separata(Walker)生长发育和生殖的关系及变温条件下粘虫主要能源物质代谢的变化规律。【方法】将粘虫卵置于光周期均为14L∶10D,温度分别为25℃和30℃日恒温和白天30℃、夜晚20℃日变温的条件下饲养,观察记录25℃和30/20℃下的成虫产卵及卵巢管发育情况,再取30℃和30/20℃下饲养获得的3龄幼虫、6龄幼虫、蛹和1日龄成虫,测定其糖原、海藻糖和甘油三酯3种能源物质的含量及海藻糖酶、3-磷酸甘油醛脱氢酶、3-磷酸甘油脱氢酶及3-羟酰辅酶A脱氢酶等4种主要能源物质代谢酶的活性。【结果】25℃与30/20℃饲养条件下相比,1日龄雌成虫卵巢管发育明显滞后,但单雌产卵量显著较多;蛹期糖原、海藻糖和甘油三酯的含量均高于3龄和6龄幼虫,成虫期各能源物质含量均较低。30/20℃日变温下粘虫体内供试3种能源物质的含量显著高于30℃日恒温(6龄幼虫和蛹期甘油三酯含量在两温度下无显著差异);温度变化对供试4种酶活性的影响差异显著。【结论】温度变化对粘虫的生长发育和繁殖具有显著的影响。在粘虫生长发育过程中以糖代谢为主;变温会加速糖代谢,减缓部分发育阶段的脂代谢,更有利能源物质的积累。     

The long-distance migration of Nilaparvata lugens (Stål) (Delphacidae) in China: radar observations of mass return flight in the autumn

Abstract.

• 1 A case study is presented of the autumn migration of the brown planthopper, Nilaparvata lugens (Stål), in the area of Nanjing in the People's Republic of China. The study was made using a high frequency (8 mm wavelength) radar and a net suspended from a kytoon.
• 2 The observations confirmed that long-distance return migrations occur in China in mid and late September, with N.lugens being carried on the prevailing north-easterly wind towards the autumn infestation and overwintering areas of the species.
• 3 After mass take-off in the late afternoon or at dusk, the migrants flew for several hours during the evening, often in a dense layer which formed at heights between about 400 and 1000m above ground. These layers often had well-defined ceilings corresponding to an air temperature of about 16°C. The migration height was above the top of the surface temperature inversion, i.e. the migrants did not fly at the height of the warmest air.
• 4 The dense layer concentrations overflying the radar were backtracked to source areas up to 240 km away in the north-east of Jiangsu Province. Planthoppers observed emigrating from the Nanjing area would reach areas in south Anhui Province or north Jiangxi Province if they flew for 12 h.
• 5 There was a second period of mass take-off at dawn. Insect layers sometimes formed but did not last longer than 1–2h.
• 6 The present results were strikingly different from those previously observed in the dry season in the Philippines, where migratory flight durations were largely confined to periods of about 30min at dusk and dawn.
• 7 Our observations are discussed in relation to the equator-wards return migrations undertaken in autumn by other insect species, and the importance of these migrations for the maintenance of long-flying genotypes in the overwintering populations is considered.

     

Identification of Mythmna separata-induced maize volatile synomones that attract the parasitoid Campoletis chlorideae

Abstract:  Campoletis chlorideae Uchida (Hym., Ichneumonidae) is an important solitary koinobiont larval endoparasitoid of many noctuid species including Mythmna separata (Lep., Noctuidae). In the present study, maize volatiles induced by feeding damage of M. separata were found to be attractive to C. chlorideae in a Y-tube olfactometer. Eleven compounds were released in significant amounts from M. separata -infested maize seedlings, of which five compounds, ( Z )-3-hexen-1-ol, ( Z )-3-hexenyl acetate, ( E )-2-hexenal, linalool and phenylethyl acetate were chosen for electrophysiological and behavioural tests. All five compounds elicited electroantennogram responses in C. chlorideae . However, only pure ( Z )-3-hexenyl acetate and linalool were attractive to the parasitoid in the Y-tube. Interestingly, linalool was also attractive to starved parasitoids over a range of doses tested. These results suggested that ( Z )-3-hexenyl acetate and linalool may be key infochemicals in the host-foraging behaviour of C. chlorideae , and linalool may act as a food-source signal for the parasitoid.