Entwicklung, Fraßleistung und Beutepräferenz vonHippodamia convergens Guer.-Men. (Col., Coccinellidae) mitThrips tabaci Lind. (Thys., Thripidae) sowie zwei Aphidenarten als Beute

Thrips tabaci Lind. is very difficult to control and thus one of the most important pests of leek in Europe. As an alternative to insecticides biological control may be carried out by making use of beneficial insects, the Coccinellidae being one of the most important predatory families. In the present study laboratory trials were carried out withHippodamia convergens Guer.-Men., one of the polyphagous representatives of the lady birds, to figure out the feeding activity, development and prey preference ofH. convergens against the onion thrips in comparison with two aphid species. H. convergens developed fully when fed exclusivelyT. tabaci larvae, although mortality was considerably higher and development took much longer. When fed thrips the complete development lasted 29,8 days on an average, the mortality reaching 88%. When offeredAcyrthosiphon pisum (Harris)H. convergens took only 24 days for development with a mortality of only 16%. Above all, the fourth larval instar and the pupa suffered from a very high mortality, reaching 45 and 50% respectively. WithA. pisum as a prey mortality decreased to only 6%. The duration of the pupal development was not affected by the prey species. The feeding activity ofH. convergens increased significantly during the development. The larvae of the second and fourth instar predated 28 and 170 thrips larvae respectively per day as a maximum. The adults achieved the highest feeding activity, predating more than 300 thrips larvae in 24 hours. When adding up the number of prey individuals per day for each developmental instar, the L₂ larvae predated more than 90 and the L₄ larvae more than 1000 thrips larvae. When offered thrips larvae andMyzus persicae (Sulz.) simultaneously, there was an increasing prey preference during the development ofH. convergens from first larval instar to adult. As to the last instars there was 20–25% less predation of thrips larvae compared to the aphids during 24 hours.     

Fecundity and larval development of Monochamus galloprovincialis (Coleoptera Cerambycidae) in experimental breeding

?The study aimed at clarifying basic life traits (fecundity, mortality and development) of Monochamus galloprovincialis, the vector of Bursaphelenchus xylophilus, the causative agent of the Pine Wilt Disease, in Portugal.

? Mating and oviposition experiments were conducted on P. sylvestris logs under laboratory conditions during two years. Larval development was followed outdoors.

? Fecundity was high, with 138.2 eggs per female.

? For the first time, the number of larval instars (4) in M. galloprovincialis was recognized and instars were described.

? Informations are provided on the shape and size of the larval galleries. Boring of galleries in sapwood and heartwood started at the third instar. All instars could overwinter but adults emerged simultaneously resulting in a univoltine life cycle for the majority of the individuals.

? An obligatory diapause in the forth instar was assumed. However, 8.1% of the insects had a two year development.

? Important differences in mortality were noted between the two experimental years, which could be explained by differences on the size of the breeding logs.

? There is a high biological proximity between M. galloprovincialis populations in France and those in Portugal and Northern Europe. However, a higher fecundity and longevity was observed in France, as well as a higher percentage of insects with a two year development, compared with portuguese populations.

     

Reproductive strategies and food sources used by Acerophagus n. sp. near coccois, a new successful parasitoid of the invasive mealybug Phenacoccus peruvianus

Phenacoccus peruvianus Granara de Willink (Hemiptera: Pseudococcidae) is a new invasive mealybug that causes important damages in ornamental plants in urban landscapes and nurseries in Southern Europe. Recently, a new species of genus Acerophagus Smith (Hymenoptera: Encyrtidae) has been recorded as the main parasitoid of P. peruvianus in Spain, displacing the native parasitoid Leptomastix epona Walker (Hymenoptera: Encyrtidae). In this work, we have determined some traits of the reproductive and feeding strategies of Acerophagus sp.: fecundity, immature developmental time, host instar suitability, and preference when parasitizing P. peruvianus, and the effect of natural occurring sugar sources on adult longevity. Acerophagus sp. egg load reached its maximum when it was 5 days old. Second and third nymphal instars and adults were suitable for parasitism and immature development (efficient encapsulation was low). Immature development lasted between 20 and 22 days. Acerophagus sp. developed as a solitary parasitoid in the second instar and as a gregarious parasitoid in older instars (2–4 parasitoids per host). All the emerged offspring were females. Acerophagus sp. always preferred older instars when different host instars were available. Finally, adults lived more than 20 days when fed on honey, but they lived fewer than 3 days when fed on naturally occurring sugar sources (host honeydew and host plant flowers, Bougainvillea glabra). The consequences of these characteristics on biological control and parasitoid rearing are discussed.     

Development, feeding and reproduction responses of Adalia fasciatopunctata revelierei(Mulsant) (Coleoptera: Coccinellidae) to Hyalopterus pruni(Geoffroy) (Homoptera: Aphididae)

This study was carried out to determine the development, survival and reproduction responses of Adalia fasciatopunctata revelierei (Mulsant) (Coleoptera: Coccinellidae) feeding on Hyalopterus pruni (Geoffroy) (Homoptera: Aphididae), using 20, 40, 80, 160 and 250 prey densities. All experiments were conducted at 25±1°C, 60±5% relative humidity, 16:8 light:dark under laboratory conditions. The average daily prey consumption of A. fasciatopunctata revelierei immatures and adults increased with increasing prey densities. Predation was not different for the larval stages at 80, 160 and 250 prey densities. The longevities of adult females were 35.67, 35.33, 49.00, 58.33 and 57.16 days when 20, 40, 80, 160 and 250 H. pruni were provided, respectively. The mean daily and total fecundity of A. fasciatopunctata revelierei increased with increasing prey densities. Females of A. fasciatopunctata revelierei feeding on H. pruni laid 89 eggs at 20 prey density and 301.67 eggs at 160 prey density. The search rate of females was higher than that of all larval instars; and the search rate of the fourth-instar larvae was higher than that of younger instars. Handling time decreased with development from larval stages to adult.     

白蜡窄吉丁幼虫的龄数和龄期测定

采用林间定期调查取样的方法，测定白蜡窄吉丁幼虫的龄数以及各龄的龄期；分别测量不同发育阶段幼虫的体长、体宽(第7腹节最宽处)、前胸背板宽、口缘宽、尾又长和尾叉前缘宽等6项指标，以期找出区分和判定幼虫虫龄的最佳形态特征及指标。结果表明：白蜡窄吉丁幼虫有4龄，尾又及其长度可作为理想的分龄特征和分龄指标；幼虫的口缘宽度也可作为指标之一；体长、体宽、前胸背板宽和尾又前缘宽变异较大，不宜用于分龄。研究还发现：幼虫尾叉内侧的形态特征是区分幼虫虫龄的简洁而方便的方法。利用种群众数龄期法测定各龄的平均龄期分别为：1龄18．1d，2龄11．2d，3龄10．7d，4龄261．2d，幼虫期共为301．3d。     

Impact of neem and chinaberry fruit extracts on the pest/parasitoid (Pieris rapae/Hyposoter ebeninus) interactions

A new technique was performed to simulate exposure of the host Pieris rapae larvae to both botanical treatment and the parasitoid Hyposoter eheninus in different sequences. It was found that: host larvae subjected to both parasitoid and 1?% neem treatment showed significant or insignificant reductions both in pupal formation as well as adult emergence percentages when treatment preceded or followed parasitism, respectively. Both neem treatments revealed significant prolongation in the development of unparasitized and parasitized larvae (on average 4 to 5 days delay), whereas chinaberry caused significant prolongation only among parasitized larvae (on average 2.7 days delay in egg-larval duration). Fate of parasitism among untreated hosts was found to be faster than among neem-treated ones. Parasitism percentages among 1 and 0.5?% neem-treated third instar host larvae held 7 days before parasitism reached 3 and 2 times that achieved among those reared on untreated diet for the same period, ­respectively. It was concluded that prolongation of the preferred target instars of the host, due to neem treatments, increased the chance for parasitism. Nevertheless, treatment with neem at the LC₅₀ level exhibited a great reduction in parasitoid progeny. However, a lower concentration (LC₂₅) could reasonably potentiate parasitism without drastic losses in parasitoid emergence.     

The colonization preference and population trends of larval fig psylla, <Emphasis Type="Italic">Homotoma ficus</Emphasis> L. (Hemiptera: Homotomidae)

The colonization preference and population trends of larval fig psylla Homotoma ficus L. were studied in Bursa, northwestern Turkey, from March 2000 to July 2001. Homotoma ficus overwintered at the egg stage on terminal buds and lenticels of shoots. Larval emergence occurred on 30th and 11th March in 2000 and 2001, respectively. Degree-day (DD) accumulations since 1st January indicate that the emergence of first larvae averaged 47 DD based on the larval developmental threshold of 10.9°C. Although the population trends of Homotoma ficus larvae were affected by temperature and rainfall, there was only significant relationship between larval abundance and temperature. The first instar larvae significantly preferred the bottom and the inside stipule of leaves. The second instar larvae distributed not only on expanding green tissues but also on both the upper and lower surface of leaves corresponding to the fig bud development period. Third to fifth instars colonized significantly greater on the bottom of leaves compared with the stipule and upper surface. In addition, significant linear relationship was found between fig phenology and cumulative larval counts. The importance of the colonization preference of larval instars and the use of fig phenology as well as DD for timing of insecticide treatments are discussed.     

苹小吉丁(鞘翅目：吉丁甲科)幼虫龄数的测定

In recent years, Agrilus mali Matsumura has outbroken in the Xinjiang wild fruit forest, and become the primary threat to Malus sieversii. In early study, the larvae of Agrilus mali were divided into six instars. However, the particular reason and method were not mentioned, and the larvae of Genus Agrilus were usually divided into four or five instars. For better pest forecasting and control strategies, the determination of larval instars was studied again. A.mali larvae were sampled periodically in forest, and the eggs were collected to hatch the first instar larvae. Three characteristics (i. e. peristoma width, urogomphus length and body length) were measured by binocular microscope with an eyepiece micrometer. According to the Dyar's law, the data were managed with frequency analysis, and examined by one-way ANOVA method, Crosby ratio and checked with larvae which were molting when sampling. The results showed that, the A. mali larva has five instars, and all three determination characteristics are effective except body length.     

Development,life history characteristics and behaviour of mealybug predator, <Emphasis Type="Italic">Spalgis epius</Emphasis> (Westwood) (Lepidoptera: Lycaenidae) on <Emphasis Type="Italic">Planococcus citri</Emphasis> (Risso) (Homoptera: Pseudococcidae)

The development of immature stages, life history and behaviour of mealybug predator, Spalgis epius (Westwood) (Lepidoptera: Lycaenidae) reared on mealybugs, Planococcus citri (Risso) (Homoptera: Pseudococcidae) was studied in the laboratory. Larvae of S. epius are a potential predator of different species of mealybugs in India. The predator completed its life cycle in 23.8 days with four larval instars. Mean incubation period of egg was 3.9 days. Mean duration of development of larval stages, prepupa and pupa was 9.4, 0.9 and 9.5 days, respectively. The first and last instar larvae measured 1.9 and 11.4 mm in length, respectively. Length and width were not significantly correlated in larvae. Head capsule width was not significantly correlated with larval length in any instar. The female-to-male sex ratio was 1.45:1. Adults were ready for mating one day after eclosion. The pairs remained in copula on an average of 61.3 min. The gravid female contained 74.6 eggs in the ovaries. Unfed butterflies (both males and females) lived 3–4 days, significantly shorter than those with access to water (6–7 days). The results of this study will be useful to utilize the predator as a biocontrol agent.     

环斑猛猎蝽生物学特性的研究*

据北京室内饲养观察，环斑猛猎蝽一年发生一代，以４龄若虫越冬。卵期９．９±１．１ｄ。若虫共５龄，历期３１５．０±４．９ｄ。成虫羽化后７－２５ｄ交配，交配后２２－２３ｄ开始产卵。描述了各虫态形态特征。记述了生物学特性。试验表明该虫是杨扇舟蛾、黄刺蛾、杨叶蜂、舞毒蛾、油松毛虫、黄褐天幕毛虫、刺槐蚜等多种林木害虫的捕食性天敌。     

Adult morphology and life cycle under constant temperatures of the predator Rhyzobius lophanthae Blaisdell (Col., Coccinellidae)

The external and internal morphological characteristics of the predator Rhyzobius lophanthae Blaisdell (Coleoptera, Coccinellidae) were studied. The head, antenna, thorax elytra, hind wings, legs and abdomen are described. The adult has an average length of about 2.5?mm and width of 1.8?mm. The flagellum of the antenna consists of 9 segments. The whole surface of thorax and elytra is covered by setae. The tarsus of the 3 legs is 3-segmented. An external morphological difference between male and female is the outline of the 5^th sternite. The alimentary canal, the central nervous system, and the reproductive system of both male and female are also described. The testes consist of 10 follicles and the ovaries of 10 ovarioles. The life cycle of R. lophanthae was studied by rearing the predator on the diaspidid Chrysomphalus aonidum (Linnaeus). The duration of the development of the embryo, 1^st, 2^nd, 3^rd, 4^th larval instars, pupa and preoviposition period of adults were measured at 15, 20, 25 and 30?°C.     

Temperature-dependent development of Sesamia nonagrioides

The effect of various constant temperatures on survival, development and adult longevity of Sesamia nonagrioides Lefébvre (Lepidoptera: Noctuidae) was studied under laboratory conditions. The following temperatures were tested: 14, 17, 21, 25 and 31 °C. The percentage of individuals that completed development at each temperature as well as the days needed for the emergence of the pupa and adult eclosion were measured. Adult longevity was estimated under the same conditions. Development time decreased significantly with increasing temperature within the range 14–25 °C. Survival was higher at medium temperatures (17–25 °C) in comparison with that at more extreme temperature regimens (14 and 31 °C). Egg and first larval instars were the stages where S. nonagrioides suffered the highest mortality levels at all temperatures. The highest survival was recorded with experimental individuals aging between the third and fifth larval instar. Thermal requirements of development (developmental thresholds, thermal constant, optimum temperature) of S. nonagrioides were estimated with application of linear and one nonlinear models (Logan I). Upper and lower developmental thresholds ranged between 31.2 and 36.2 and 7.0 and 10.3 °C, respectively. The optimum temperature for development (where maximum rate of development occurs) was estimated at between 28.1 and 30.3 °C. The thermal constant for total development was estimated at 1,000.0 degree-days. Adult longevity was also affected by temperature, as it was significantly reduced at higher temperatures (21–31 °C) compared to the lower ones (14 and 17 °C). This information would be useful in determining the critical temperatures which may affect the distribution of S. nonagrioides concerning potential climate change.     

Continuous nondestructive monitoring of larval feeding activity and development of the bamboo powderpost beetle <Emphasis Type="Italic">Dinoderus minutus</Emphasis> using acoustic emission

The life history and feeding biology of the bamboo powderpost beetle Dinoderus minutus remain poorly understood because the beetles’ oviposition, development, and feeding take place inside bamboo culms. In this study, acoustic emission (AE) monitoring was applied for continuous nondestructive analysis of larval feeding activity and development from the first instar to adult eclosion. Newly hatched larvae were inoculated individually into pieces of madake (Phyllostachys bambusoides) culms. AE hits were recorded using single AE sensors fixed onto the bamboo pieces. Generation of AE hits indicated that larval feeding activity had begun after inoculation. Based on the time course of the hourly AE hit rate, the larvae were feeding constantly during each instar, and feeding activity only ceased during periods of ecdysis and pupation. Half of the individuals examined underwent seven instars and the other half underwent eight instars. The time course of AE hit rate per 5 min exhibited periodic cycles, where continuous meals were separated by inactive phases of ca. 5 min, with an average dominant period of each instar ranging between 0.76 and 2.19 h. After correcting the AE data based on distance attenuation of AE waves, the tendency that AE amplitude increased as the larvae developed through ecdysis events became more apparent. AE monitoring continued after adult eclosion, and the feeding activity of the newly emerged adults continued almost ceaselessly during the Reifungsfrass period.     

Entwicklung,Lebensdauer, Fruchtbarkeit und Geschlechtsverhältnis der RaubmilbeAmblyseius longispinosus (Evans) mitTetranychus cinnabarinus (Boisd.) als Beute

The development, longevity, fecundity and sex ratio of the predatory miteAmblyseius longispinosus (Evans) were studied at different constant and alternating temperatures withTetranychus cinnabarinus as prey. Alternating temperatures had no significant effect on the developmental times, in comparison with optimal constant temperature. At the alternating temperature of 33/23°C the mean duration of the life cycle from egg to adult was obvious longer with 5.0 and 4.4 days forA. longispinosus females and males than at alternating temperature of 30/20°C with 4.2 and 4.1 days for females and males. At 25°C constantly the egg stage was the longest during development and required a mean of 2.2 days.A. longispinosus females and males remained in larval stage for 0.5 and 0.6 days. The protonymphal and deutonymphal stage lasted for 0.7 and 1.1 for females and for 0.7 days for males, respectively. At all temperatures the development of females required significantly longer than of males. Longevity ofA. longispinosus adults was variable to tested temperatures: At 25°C females lived for 33.1 days, at 30/20°C for 30.6 days and at 33/23°C for 29.9 days. At 25°CA. longispinosus females produced a mean total progeny of 48.8 eggs and the mean duration of oviposition period was 21 days; at 30/20°C and at 33/23°C a mean number of 49.1 and 48.2 eggs was laid during an oviposition period of 20 days. Temperature had no effect on the sex ratio of predatory mites, about 70% of mites became females at all temperatures.     

豫西地区中华松针蚧生物生态学特性初步研究

中华松针蚧Sonsaucoccus sinensis Chen雌雄异型，1a发生1代，雌虫2龄，终生被蜡质蚧壳，不爬出壳外。雄虫3龄，3龄若虫爬出壳外化蛹，进而羽化成虫。滞育期在6月下旬至8月中旬，滞育期解除后1龄寄生若虫蜕变为2龄无肢若虫，继续危害至10月份，并以2龄无肢若虫越冬。各虫态出现期因海拔和气温变化而有差异。海拔高、气温低发育迟，反之发育早。该虫主要是通过风、雨和人为活动等途径传播。化学防治的有利时机在初孵若虫期。     

Characterization of larval instars of artemisia weevil, Adosomus sp.

The artemisia weevil, Adosomus sp., has become an important wormwood (Artemisia ordosoca and A. sphaerocephala) pest in recent years in Ningxia Province, China. The number of larval instars should be determined before further studies on its life history, biology and integrate management of pest (IMP). In this study, we measured the length and width of head capsule, based on frequency histograms and Dyar’s law, from which we concluded that the larvae of Adosomus sp. have four instars. Of the two variables measured, the width of head capsule provided the best division of instars. The average width of head capsule of the 1st instar larvae was 1.348±0.152 mm, the 2nd 2.109±0.199 mm, the 3rd 3.563±0.492 mm and the 4th 5.974±0.581 mm.     

Wirksamkeit verschiedener Komponenten vonBacillus Thuringiensis Berliner auf drei Larvenstadien vonPieris rapae L.

Zusammenfassung Sporen und Kristalle vonB. thuringiensis wurden aus einem Handelspr?parat durch alkalische Extraktion und differentiale Zentrifugation getrennt. Ihre Wirkung auf frisch geh?utete Larven des 3ten, 4ten und 5ten Stadiums wurde untersucht und mit der vom Rohpr?parat unter gleidien Bedingungen verglichen. 5–7 Konzentrationen wurden bei jedem Versuch verwendet und die LC₅₀ Werte wurden in jedem Fall von den Konzentration/Sterblichkeit Kurven aligeleitet. Die Ergebnisse zeigen: 1. Die Anf?lligkeit der Larven gegen jede der bakteriellen Komponenten ebenso wie gegen das Rohpr?parat nimmt mit deren Entwicklung ab. 2. In den drei untersuchten Larvenstadien war das Rohpr?parat etwas wirksamer als Sporen oder Kristalle. Dies wurde besonders im 5ten Stadium deutlich. 3. Nur im 5ten Stadium zeigten die Kristalle eine deutlich h?here Pathogenit?t als die Sporen. 4. Sporen scheinen bei der Pathogenit?t des Rohpr?parates eine geringere Rolle zu Spielen. Ihre Wirkung wurde durch die zunehmende Toleranz der Larven bei Erreichen des 5ten Stadiums betr?chtlich verdeckt.

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Summary Spores and crystals ofB. thuringiensis were separated from a commercial preparation by alkali extraction and differential centrifugation. Their effectiveness on newly moulted 3rd, 4th and 5th instar larvae was tested and compared with that of the crude preparation under identical conditions. Five to 7 concentrations were used in every tast and the LC-50-values were deduced in every case from concentration/mortality curves. The results indicate that: 1. The susceptibility of the larvae to any of the bacterial components as well as to the crude preparation decreases with their devlopment. 2. In the three investigated larval instars the crude preparations was slightly more effective than spores or crystals. This was particulary obvious in the 5th instar. 3. Only in the 5th larval instar, crystals showed a markedly higher pathogenicity than the spores. 4. Spores seem to play the minor role in the pathogenicity of the crude preparation. Their effectiveness was considerably concealed through the increasing tolerance of the larvae by reaching the 5th instar.

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Faculty of Science, Ain-Shams University     

Population dynamics of Dasiops inedulis (Diptera: Lonchaeidae) and its biotic and abiotic mortality factors in Colombian sweet passionfruit orchards

Throughout South America, the lonchaeid flies Dasiops spp. are important herbivores of passionfruit crops. However, little is known on the biology and ecology of these insects, resulting in inadequate pest management schemes. In this study, we describe Dasiops inedulis population dynamics in Colombian sweet passionfruit (SP; Passiflora ligularis Juss.) and elucidate biotic mortality factors at different fly developmental stages. From August 2009 to July 2010, D. inedulis and Dasiops spp. abundance was assessed through monthly McPhail bait trapping and collection of SP flower buds, flowers, and immature fruits. Mortality levels of D. inedulis were determined for early instar larvae by ovary dissection and for late-instar larvae or pupae by prey removal trials. Maximum infestation reached 80 % in fruits and flower buds, and bud infestation correlated with precipitation during the previous month. Two days after oviposition, 8.2 ± 2.3 (mean ± SD) Dasiops sp. eggs were found in SP ovaries and 4.4 ± 1.2 late-instar larvae were recovered from immature fruits at day 14. Upon larval drop on the orchard soil, 74.8 % larvae burrowed within the soil within 9 min, while 12.5 % larvae were attacked by ants. In-field mortality of young pupae amounted to 75.3 ± 7.0 %, with vertebrate predators likely causing 12.1 ± 6.0 % mortality. Late-instar larvae and pupae appear highly vulnerable to natural enemy action, with the ground-foraging predator community mainly composed of ants (80.37 %) and ground beetles (9.17 %). Our findings should help develop integrated pest management (IPM) tactics for SP crops.