Comparative laboratory experiment withOrius insidiosus andOrius albidipennis (Het.: anthocoridae), two candidates for biological control in glasshouses

The predatory bugsOrius insidiosus andOrius albidipennis are potential candidates for biocontrol of the thrips,Frankliniella occidentalis. Laboratory experiments showed thatO. albidipennis lays significantly more eggs thanO. insidiosus while its life cycle is shorter. As more eggs are laid byO. albidipennis in the beginning of the oviposition cycle, this anthocorid may be considered as the better biocontrol agent.     

粘虫飞行对生殖及寿命的影响

该文报道了粘虫Mythimna separata（Walker）成虫飞行后产卵、交配及寿命的研究结果。1日龄成虫飞行6 h、12 h、18 h、24 h后的产卵前期均显著短于对照的,其中飞行6 h、12 h的比对照的短2天以上,产卵量均比对照的高。对1～5日龄成虫分别飞行23.5 h后的研究结果表明,1日龄飞行的产卵前期和上述结果相一致。2～4日龄飞行的与对照的没有显著差异,但产卵量则随飞行日龄的延迟而逐渐减少。5日龄飞行的产卵前期显著延长,产卵量已不到对照的一半。所有经过飞行的成虫产卵高峰日比对照的早1天。不同日龄成虫飞行时间、距离与成虫产卵量的关系为：1～3日龄飞行时间、距离长的个体产卵量也高;但4～5日龄的成虫飞行时间与距离越长,其产卵量越少,表现出明显的卵子发生飞行拮抗症(oogenesis-flight syndrome)。除了5日龄飞行的成虫交配率有所下降以外,所有经过飞行的成虫产卵历期、交配率及寿命与对照的没有显著差异。最后,根据这些结果,对粘虫迁飞的起飞时期,迁飞在粘虫生殖、种群动态及成灾规律中的作用进行了讨论。     

Biology ofAnastatus biproruli (Hym.: Eupelmidae) a parasitoid ofBiprorulus bibax (Hem.: Pentatomidae)

The effect of temperature on the rate of development ofAnastatus biproruli (Girault) was determined by rearing individuals on eggs ofBiprorulus bibax Breddin under a range of constant temperatures (17.5–40.0°C). Rate of development changed in a linear fashion from 17.5–35.0°C and the lower developmental threshold was estimated to be 12.8°C. An estimated 331.8 degree days were required for development. Survival of developing parasitoids was optimal (72–90%) between 25–35°C. Longevity of virgin adults ranged from 12–26 days at 22.5–35°C but was only 3.6 days at 37.5°C. Mated females produced a mean of 54.6 progeny during an average lifespan of 36.4 days at 30°C. Progeny were produced only during the first 21 days of adulthood but post-reproductive females still attacked and killed hosts. FemaleA. biproruli overwintered successfully, and were able to parasitise host eggs if direct sunlight was available.A. biproruli also overwintered as immature stages in host eggs. The biology ofA. biproruli is discussed with regard to its importance as a natural enemy ofB. bibax.     

Acceptance and suitability of four plant substrates for rearing Orius sauteri (Hemiptera: Anthocoridae)

Orius sauteri (Poppius) is an important hemipterous predator that has been mass-reared for biological control of numerous pests in protected crop-production systems. To find a good oviposition substrate for mass-rearing this predator under insectary conditions [25°C, 65 ± 5% relative humidity, and a photoperiod of 16:8 (L:D) h], we compared kidney bean, soybean, broad bean sprouts and fresh leaves of kidney bean. We found that O. sauteri made more punctures and laid more eggs in kidney bean sprouts than in the other substrates examined. However, there were no significant differences among substrates in the proportion of punctures receiving eggs. Female O. sauteri laid the most eggs (as many as 68 eggs) in kidney bean sprouts and also had the shortest pre-oviposition period on this plant material. In addition, there were no significant differences in total oviposition durations or female longevity among the four plant substrates. The hatch rates of nymphs in the sprouts and leaves of kidney bean (>90%) were higher than those in soybean and broad bean sprouts. Thus, we found that the kidney bean sprout was the most suitable substrate for mass-rearing of O. sauteri.     

施钾对苜蓿上牛角花齿蓟马产卵选择、生长发育、 成虫寿命和繁殖力的影响

【目的】为了探讨施钾对苜蓿上牛角花齿蓟马Odontothrips loti的产卵选择、生长发育、成虫寿命和繁殖力的影响,明确施钾苜蓿叶片营养物含量与牛角花齿蓟马生命参数的关系。【方法】在不同钾量(40, 60, 80和100 mg/kg)处理下(以不施钾作为对照),观察记录牛角花齿蓟马在紫花苜蓿品种甘农3号Medicago sativa cv. Gannong No. 3叶片上的产卵量,幼期各龄期发育历期和存活率以及二代成虫的寿命和繁殖力,同时测定不同施钾量下苜蓿叶片的可溶性糖、游离氨基酸及钾含量。【结果】随着施钾量的增加,牛角花齿蓟马在苜蓿叶片上的产卵量(粒/复叶)先降低后升高,在60 mg/kg钾处理降幅最大,较对照降低了45.58%;卵孵化率和1-2龄若虫的存活率变化不显著,但3-4龄若虫的存活率和幼期总存活率显著下降,分别在100 mg/kg 和80 mg/kg钾处理下降幅最大,较对照分别下降了54.36%和48.48%。不同施钾量下苜蓿叶片上牛角花齿蓟马卵和1-2龄若虫发育历期无显著变化,3-4龄若虫及幼期总发育历期均延长;牛角花齿蓟马二代成虫的繁殖力均显著下降,成虫寿命显著缩短(40 mg/kg钾处理除外)。施钾后,苜蓿叶片可溶性糖含量、钾含量和糖氮比增大,游离氨基酸含量减少。相关关系分析表明,苜蓿叶片钾含量与牛角花齿蓟马幼期总存活率和成虫繁殖力无显著相关性,而苜蓿叶片可溶性糖含量和糖氮比均与3-4龄若虫存活率和繁殖力极显著负相关,与幼期总存活率呈显著负相关。【结论】施钾苜蓿对牛角花齿蓟马成虫产卵产生显著的排趋性;施钾提高了苜蓿叶片的可溶性糖含量及糖氮比,不利于若虫的生长发育,并使成虫寿命缩短、繁殖力下降,对牛角花齿蓟马产生了显著的抗生作用。     

Laboratory studies on the direct effect of temperature on the freshwater vector snail,Indoplanorbis exustus (Deshyes)

The present study includes the effect of temperature on the survival of young and adult snails, embryonic development, embryonic growth and egg laying of Indoplanorbis exustus. In Indoplanorbis exustus the bottom lethal temperature was 7.0°C and 7.5°C for young and adults respectively. while the upper lethal temperature was 34.0°C and 32.0°C for young and adult snails respectively. Between the temperatures 12.5°C and 36.5°C the embryonic development was accelerated and the incubation period was shortened. The growth of embryos was found to be faster at 25.0°C. The optimum temperature for egg laying was observed at 25.0°C.     

Parasitism of the Coffee Berry Borer Hypothenemus hampei by Trichogramma pretiosum in the Laboratory

Parasitism of the coffee berry borer, Hypothenemus hampei (Ferrari) by Trichogramma pretiosum Riley resulted in high mortality of developing parasitoids and a low prevalence of adult emergence. A laboratory colony of T. pretiosum reproducing in H. hampei failed after three generations. Adult female T. pretiosum that developed in H. hampei were smaller and produced fewer eggs than conspecifics that developed in a standard lepidopteran host, Sitotroga cerealella (Olivier). Parasitoids that emerged from H. hampei preferentially parasitized S. cerealella over H. hampei. We conclude that T. pretiosum has little potential for biocontrol of the coffee berry borer.     

Effect of male and female multiple mating on the fecundity, fertility, and longevity of diamondback moth, Plutella xylostella (L.)

Abstract:  The effect of diamondback moth (DBM), Plutella xylostella (Lep., Plutellidae) male and female multiple mating on fecundity, fertility, and longevity was studied. Males could mate for five times with virgin females during scotophase. The successful copulation rates, fecundity of female, and longevity of both females and males decreased when male mating times increased, whereas copulation duration increased. Correlation coefficient between copulation duration and male mating times was significant ( r  = 0.7358, P = 0.0001, spearman rank-order correlation). There were linear relationships between mating history of males and longevities of males and females, and regression relationships between them were significant. Mated females had similar daily reproductive pattern, which laid the most eggs on the first day after mating in spite of their mates' mating history. Virgin females laid some infertile eggs before they died. Most of the females mated once during their lifespan but 19.9% of females mated twice when one female kept with one male during scotophase. There were no significant differences in the fecundity, fertility and longevity between the single- and twice-mated females. Correlation coefficient between copulation duration and female mating times was not significant ( r  = 0.0860, P = 0.8575). Results suggested that DBM females may be monandrous. Multiple mating did not increase male or female mating fitness.     

Biological parameters of the predatory mite Cheletomimus bakeri (Acari: Cheyletidae) feeding on Tetranychus cinnabarinus (Acari: Tetranychidae)

Developmental periods of egg, larva and nymphal stages and fecundity as well as predation of Cheletomimus bakeri (Acari: Cheyletidae) feeding on Tetranychus cinnabarinus (Acari: Tetranychidae) were evaluated at different temperatures (15, 20, 25, 30 and 35°C) at 65 ± 10% relative humidity and 16 L: 8D in the laboratory. The development periods of C. bakeri from egg through adult decreased significantly when the temperature was increased from 20°C to 35°C. Egg and total development periods of C. bakeri at 20, 25, 30 and 35°C were 13.86, 7.98, 5.07, 4.08 days and 58.66, 41.51, 21.21, 22.92 days, respectively. The highest numbers of total and daily egg production were found at 20°C and 30°C, respectively. Net reproductive rate (R₀ = 13.29), mean generation time (T = 88.30), gross reproductive rate (GRR = 17.46) and doubling time (DT = 23.66) were the highest at 20°C. The intrinsic rate of increase (r_m = 0.0592) and finite capacity for increase (λ = 1.061) for C. bakeri were the highest at 30°C. Predation of C. bakeri increased throughout the range of prey densities. The highest consumption number of C. bakeri feeding on T. cinnabarinus males per day was 4.63, 4.70 and 4.60 when confined to 40, 80 and 160 individuals, respectively. Our data suggest that C. bakeri does not appear to have much promise for the control of spider mites because of the characteristics of the predator such as slow development period, poor searching capacity and low intrinsic rate of increase.     

不同温度对麦蛾茧蜂实验种群生长发育的影响

在15,20,25和30℃4个温度梯度下,测定了麦蛾茧蜂Habrobracon hebetor(Say)成蜂寿命、生殖力、发育历期等生物学参数。结果表明,在实验温度范围内,卵期在15℃最长,为(9.50±1.39)d;幼虫发育历期在20℃最长,为(6.60±1.41)d;蛹期在15℃最长,为(23.71±2.63)d。雌蜂的寿命在15℃时最长,为(50.15±6.9)d;30℃时最短,为(9.20±3.12)d雄蜂的寿命在15℃时最长,为(11.45±3.52)d;30℃时最短为(5.90±1.62)d。产卵量在25℃最大,为(208.50±40.12)粒;羽化数、羽化率在30℃最高,分别为(23.60±9.33)%和(35.87±13.87)%;温度变化对麦蛾茧蜂雌成蜂生物学参数具有显著影响。     

Age- and density-related oviposition behavior of the European corn borer,Ostrinia nubilalis (Lepidoptera: Pyralidae)

Age-related oviposition patterns ofOstrinia nubilalis were studied at three population densities in the laboratory by releasing newly eclosed adults in wire-screened cages and analyzing their oviposition throughout the adult stage with digital analysis. Oviposition sequences of individual females depositing egg masses were documented on the third and seventh nights after eclosion with a video camcorder. During a sequence, a female produced an egg in an average time of 15 or 26 s on the third and seventh nights, respectively, and completed depositing an egg mass the size of 20–39 eggs in an average time of 316 and 525 s, respectively. Females were not easily disturbed during egg mass deposition and pulsated their abdomen before deposition of each egg. Females produced few egg masses the first night after eclosion. Oviposition increased on nights 2 and 3 but declined steadily thereafter as females matured. Females older than 6 nights produced fewer egg masses; the proportion of egg masses with fewer than 20 eggs increased gradually. By the end of the adults' lifetime, nearly 100% of the egg masses had fewer than 20 eggs. The data are fundamental to our research to define the role of phytochemicals in modifying oviposition behavior of the European corn borer.     

Strong material benefits and no longevity costs of multiple mating in an extremely polyandrous leaf beetle, Chrysochus cobaltinus (Coleoptera: Chrysomelidae)

It is well established that females of many species exhibitpolyandry. Although such behavior often increases female fitnessby augmenting fecundity or enhancing the genetic diversity andvigor of their offspring, it often reduces female longevity.It has been argued that trade-offs between these costs and benefitsshould limit the degree to which females remate. However, theexistence of highly polyandrous species suggests substantialpolyandry benefits and/or minimal costs in some systems. Femalesof the leaf beetle, Chrysochus cobaltinus, are extremely polyandrous,providing an opportunity to examine the factors influencingthe evolution of such behaviors. We compared the fecundity andlongevity of singly mated females, females that mated multipletimes with the same male, and females that mated multiple timeswith different males. Compared with females in the single matingtreatment, females in both multiple mating treatments exhibiteda significant reduction in latency to oviposition and, due toan increase in daily egg production, significant increases inlifetime fecundity. This difference diminished as the time sincelast mating increased. There were no differences in fecunditybetween the 2 multiple mating treatments, indicating that mateidentity does not influence the material benefits of multiplemating. Surprisingly, female longevity did not differ amongtreatments. The pronounced fecundity benefits that females gainfrom multiple mating, coupled with a lack of longevity costs,apparently explains the extreme polyandry in this species. Inaddition, the existence of material fitness benefits via conspecificmatings raises the intriguing possibility that in a C. cobaltinus–Chrysochusauratus hybrid zone, heterospecific matings may confer similarbenefits to Chrysochus females.     

Reproductive attributes of the eulophid Oomyzus sokolowskii,a biological control agent of diamondback moth,Plutella xylostella (Lepidoptera: Plutellidae)

Oomyzus sokolowskii (Kurdjumov) is a gregarious larval-pupal parasitoid of the diamondback moth, Plutella xylostella L. Under laboratory conditions, we explored the reproductive attributes including the functional response of O. sokolowskii and the impact of mutual interference among female parasitoids on progeny production and progeny sex ratio. In the functional response experiment, groups of 1–50 late instar larvae were exposed to groups of five female parasitoids for 48 h. Both Holling's disc equation (type II response) and Williams and Martinez's model (type III response) fit significantly better than the null-model assuming density-independent parasitation efficiency. Williams and Martinez's model was only marginally better than Holling's disc equation which explained 82% of the variation in the number of parasitized hosts. According to Holling's disc equation, the estimated maximum number of hosts parasitised during 48 h was 17 per group of five parasitoids, the estimated attack efficiency of a single female parasitoid (a) was 0.0024 larvae per hour, and the estimated handling time of a single female (T _h) was 14.4 h per host. In the mutual interference experiment 50 host larvae were exposed to different numbers of female parasitoids (P=5, 10, 20, 30, 40 and 50) for 48 h. With increasing numbers of conspecifics, the proportion of male progeny increased and total number of progeny per parasitoid decreased, yielding an estimated mutual interference constant (m) (±SE) of 0.95±0.14. The total number of wasps emerging from individual host pupae increased with increasing number of conspecifics. The age-specific fecundity of O. sokolowskii was investigated by providing 10 host larvae daily to individual female parasitoids. After 3 days of oviposition, 90% of the females were still alive and had achieved 76.4% of their lifetime fecundity. The proportion of female progeny decreased with female age. No relationship was found between female longevity and lifetime fecundity. The results suggest that parasitoid and host densities influence the progeny production and sex allocation strategy of O. sokolowskii. The information obtained from this study would help to develop a mass-rearing protocol for O. sokolowskii.     

梨小食心虫蛹重对成虫繁殖力和寿命及下一代幼虫发育的影响

【目的】本文旨在明确营养状况不同造成的梨小食心虫Grapholitha molesta(Busck)雌、雄蛹重量差异对其羽化的成虫产卵量、产卵期、寿命及下一代(F1)幼虫发育的影响。【方法】室内条件下,通过不同的饲养方法,获得个体重量不同的梨小食心虫雌、雄蛹,待其羽化交配后,记录其产卵量、产卵时间和成虫寿命;卵孵化前后,分别测量卵和初孵幼虫大小,计算卵孵化率,统计幼虫发育历期。【结果】雌蛹重量对梨小食心虫的成虫产卵量影响显著,其重量与产卵量呈正相关(y=15.505x-59.292);同一条件下,雌蛹与雄蛹重量也呈正相关(y=0.823x-0.538)。同时,雌蛹重量对成虫产卵期影响也较大,蛹重大的个体羽化的雌虫比蛹重小的个体羽化的雌虫产卵高峰期提前1 d;较重、中等和较轻蛹羽化出的雌虫个体每天产卵量高于10粒/雌的时间分别为9~10,7和5~6 d;产卵量高于5粒/雌的时间分别为12~13,9和6~7 d。而雄蛹重量对产卵量、雄成虫寿命影响没有明显影响。较轻的蛹羽化的雌成虫寿命比较重蛹羽化的雌成虫短2~3 d;而雄蛹重量对其羽化的雄成虫寿命影响没有明显规律。雌、雄蛹重量对其羽化成虫的卵孵化率、卵和初孵幼虫的大小影响均不显著,对F_1幼虫发育历期影响也不显著。【结论】梨小食心虫雌蛹重对羽化成虫的产卵量和产卵期等影响显著,田间防治时应注意在不同条件下完成发育的个体,尤其是雌虫,由于营养差异引起的个体大小对随后种群增长的影响。     

一种松突圆蚧寄生蜂Aphytis sp.的寿命与产卵研究

在19～32℃内,不供给蜂蜜时,Aphytis sp.寿命是0.8～3.1天,供给蜂蜜时,寿命可延长到3.6～15.2天.Aphytis sp.在25℃和28℃产卵量最多,分别为64.2/♀和63.0/♀,19℃和32℃分别为26.7/♀和27.8/♀.每天每雌产卵2.67～5.35个,产卵集中前5天,占总产卵量的57.6～87.0%.一般第2～3天为产卵高峰日。使用两种方法计算了 Aphytis sp.的内禀增长率,建立了世代产卵量与温度模型和逐日产卵量模型.