Seasonal population dynamic and within-plant distribution of the whitefly,Aleurotuberculatus takahashi David et Subramaniam (Hom., Aleyrodidae), and its parasitoid,Eretmocerus longipes Compere (Hym., Aphelinidae) in citrus and jasmine plantations in Fuzhou region of the southeastern China

Field investigations on seasonal population dynamic and within-plant distribution of the whiteflyAleurotuberculatus takahashi David et Subramaniam (Hom., Aleyrodidae), and its parasitoid,Eretmocerus longipes Compere (Hym., Aphelinidae) in citrus and jasmine plantations were conducted at Fuzhou, Fujian, PR China in 1996. Population levels of the whitefly and its parasitoid were approximately one times higher on jasmine plantation than on citrus. The seasonal trend of the whitefly parasitization rate on citrus was similar to that on jasmine. Maximum parasitization rates on citrus and jasmine were determined on 30. Sept. valuing 17.5% and 32.0%, respectively. Later in the season this rate gradually dropped gradually down to zero level till the end of sampling period. Populations ofA. takahashi andE. longipes were differently distributed in regard to leaf age on citrus and to plant layers on jasmine.A. takahashi was most abundant on youngest citrus leaves (age class I) averaging 14.03 indiv./leaf and on leaves in the top layer of jasmine with 20.02 indiv./leaf, whileE. longipes preferred to settle on youngest citrus leaves (age class I) (3.41 indiv./leaf) and on leaves in the middle layer of jasmine (2.95 indiv./leaf). Beside the whitefly population was distributed in a contagious pattern with K>8 on mature citrus leaves (age class III), the whitefly and parasitoid populations displayed an aggregated distribution pattern with 0<K<8 on all the leaf ages of citrus and all 3 layers of jasmine. Furthermore, the distribution of the parasitoid was even more aggregated than that of the whitefly within all leaf position tested. Regression analysis was used to fit a model of the parasitism related to the indices of whitefly (K1)/parasitoid (K2) (Y=0.1770–0.0048X, r=0.7850, p<0.05), where a=0.1770 represented the average saturation parasitism byE. longipes and b=0.0048 indicated a negative relation between the parasitism and the indices of K1/K2. From the equation it was concluded that the fitness of spatial distribution pattern between the whiteflyA. takahashi and its parasitoidE. longipes was optimal with of K1/K2-indices below 5 resulting in the highest parasitism in the field.     

Ecological studies on parasitism ofEretmocerus longipes Compere (Hym., Aphelinidae) on the whitefly,Aleurotuberculatus takahashi David et Subramaniam (Hom., Aleyrodidae) on jasmine in Fuzhou region of the southeastern China

Experiments on host-stage preference, influence of temperature on parasitization, and the feeding niche ofEretmocerus longipes Compere (Hym., Aphelinidae) parasitizingAleurotuberculatus takabashi David et Subramaniam (Hom., Aleyrodidae) on jasmine were conducted both in the laboratory of Institute of Plant Protection, Fujian Academy of Agricultural Sciences and in the field in the Fuzhou region, Fujian Province, PR China. The results showed that the most preferred host-stage ofE. longipes was the 3rd instar ofA. takahashi. The parasitization rate ofE. longipes was significantly affected by temperature, valuing 4.8% at 18 °C, 27.3% at 23 °C, and 55.1% at 33 °C, respectively. The whitefly immature stages and the parasitoid vertically selected all the layers of jasmine plant as their feeding niches, but the whitefly nymph preferred to gather on the top layer, which was considered as its suitable feeding niche, while the parasitoid selected the middle layer as its feeding niche. To measure the ability to utilize spatial resources, the feeding niche breadth was introduced to demonstrate that the parasitoid had the less wide feeding niche breadth among the all stages tested on jasmine, which revealed that the spatial activity for the parasitoid was smaller than that for any stage of the whitefly. The cluster analysis showed that the feeding niche of the parasitoid was more closely related to the 3rd instar than to any other stage of the whitefly. It was suggested that relation between the whitefly and its parasitoid was not only depending on the host-stage preference but also on the feeding niche similarity.     

Laboratory studies on the effect of temperature and humidity on the life table of the whitefly,Aleurotuberculatus takahashi David & Subramaniam (Hom., Aleyrodidae) from southeastern China

The present paper deals with developmental duration, emergence, longevity and fecundity ofAleurotuberculatus takabashi David & Subramaniam at different temperatures and humidity levels. The developmental time from egg to adult was 81.8, 56.9, 39.6, 29.9, 20.6 days at 15±1, 20±1, 25±1, 30±1, 35±1°C under constant relative humidity (RH) of 70±5%, respectively. At 25±1°C, the total developmental time was slightly affected by humidity, ranging from 46.4 days at 40±5% RH to 39.2 days at 90±5% RH. The developmental threshold and the thermal constant for the stage from egg to adult were 10.1°C and 542.8 day-degrees. It was estimated that the whitefly has about 10 generations a year in Fuzhou region in southeastern China. Lowest mortality rates of 12.4% for the egg, 6.8% for the nymph and 3.1% for the puparium were obtained at 15±1°C, while they were highest with 92.1% for the egg, 48.2% for the nymph and 36.3% for the puparium at 35±1°C. The mortality rates were slightly affected by humidity, ranging from 17.6% at 40±5% RH to 27.9% at 90±5% RH for the egg, 11.2% at 40±5% RH to 19.6% at 90±5% RH for the nymph, and 6.4% at 40±5% RH to 11.6% at 90±5% RH for the puparium. The emergence rate of adults decreased as temperature increased, ranging from 89.1% at 15±1°C to 21.5% at 35±1°C, so did the longevity of adults, ranging from 9.6 days at 15±1°C to 2.9 days at 35±1°C. The number of eggs per female was significantly affected by temperature (P.01), valuing 29.4 eggs per female at 15±1°C, 36.7 at 20±1°C, 52.4 at 25±1°C, 42.9 at 30±1°C, and 6.1 at 35±1°C. The optimal temperature for reproduction was about 25°C.     

Effect of sweetpotato whitefly, <Emphasis Type="Italic">Bemisia tabaci</Emphasis> (Homoptera: Aleyrodidae) infestation on eggplant (<Emphasis Type="Italic">Solanum melongena</Emphasis> L.) leaf

The nature of damage of sweetpotato whitefly, Bemisia tabaci (Gennadius) B biotype was investigated at the vegetative stage on eggplant (Solanum melongena L., family Solanasae, variety Baiyu) under laboratory conditions (temperature 25 ± 1°C, RH 70 ± 10% and photoperiod 12 h L:12 h D). The investigations were carried out after completing one generation of whitefly on the basis of morphology, physiology and anatomy of eggplant leaf. Significant differences were observed on three morphological parameters—leaf area, leaf fresh weight, and leaf dry weight. The reduction percentages of these three parameters were 26.6, 21.8 and 19.27%, respectively. Significant differences were also observed on two physiological parameters—chlorophyll content and rate of photosynthesis. The reduction percentages of these two parameters were 9.7 and 65.9%, respectively. There were no damaged tissue observed in the epidermis and mesophyll, but there were some damage tissue observed in the vascular bundle of infested leaf. There were no damaged vascular bundles observed in the control leaves. The non-damaged vascular bundles contained both xylem and phloem; while some damaged vascular bundles contained either xylem or phloem. Associated with the non-damaged vascular bundles on whitefly infested leaves were two settled whitefly nymphs apparently deriving nutrition from phloem sap. After one generation of whitefly infestation, the number of damaged and non-damaged vascular bundles of eggplant leaf was significantly different.     

Effect of temperature on development, mortality, fecundity, and reproduction of Aphis rumicisL. (Homoptera: Aphididae) on broadleaf dock (Rumex obtusifolius) and Swiss chard (Beta vulgaris vulgaris var. cida)

Temperature effects on developmental period, survival rate, and reproductive capacity of Aphis rumicis L. were studied on Broadleaf dock and Swiss chard at four constant temperatures (17.5°C, 20°C, 22.5°C, and 25°C). The developmental time of immature stages ranged from 10.9 days at 17.5°C to 6.5 days at 25°C on Broadleaf dock, and 11.8 days at 17.5°C to 6.5 days at 25°C on Swiss chard. The total percentage of survivorship of immature stages varied from 54.2% and 67.6% 17.5°C–25°C on Broadleaf dock, and 49.7% and 62.4% at 17.5°C–25°C on Swiss chard. The largest r _m value occurred with 0.2845 at 25°C on Broadleaf dock and with 0.2785 at 25°C on Swiss chard. The results obtained on this study indicated that Swiss chard was a less favorable host of the A. rumicis than Broadleaf dock. The optimal temperature for A. rumicis growth, developmental time, and reproduction was 22.5°C–25°C.     

Zur Pathogenität von Meloidogyne javanica (Treub) Chitw. (Nematod., Heteroderidae) bei der Kuherbse (Vigna unguiculata) in drei verschiedenen Bodentypen

Average numbers ofMeloidogyne javanica larvae and females in cowpea roots in sandy soil and sandy clayloam were significantly higher (at 5% level) than that of calcareous soil. The highest root-knot nematode population (68.3 ind./plant) was in sandy clay-loam soil, followed by sandy soil (25.8 ind./plant). The lowest was in calcareous soil (6.3 ind./plant).     

Über Schlupfwespen als Parasiten der Fliedermotte,Gracilaria syringella F. (Lep., Gracilariidae)

On Hymenoptera parasitizing the Syringia Moth, Gracilaria syringella F. (Lep., Gracilariidae)During an outbreak ofG. syringella onFraxinus excelsior in 1973 and 1974 near Munich 12 species of Hymenoptera parasitized the larvae if this pest. There were 3 chief parasite spezies;Apanteles gracilariae Wilk.,A. dilectus (Hol.) andTeleopterus sp. (probablyT. erkias Walk.) which came to nearly 90% of the whole population of parasites in each of the 4 host generations. The whole parasitization of theG. syringella larvae amounted to 12,5% (1973, 2. gen.) ot 31,2% (1973, 1.gen). Teleopterus sp. deposites the eggs int those of the moth and the full grown parasites larvae leave the young host larvae (L₂) within the leaf mines. The two species os genus Apanteles deposite their eggs in the mining larvae and their full grown larvae leave the old host larvae within the leaf rolls.     

Wirksamkeit des ParasitoidenEretmocerus debachi Rose und Rosen (Hym., Aphelinidae) gegenüber der Weißen FliegeParabemisia myricae (Kuwana) (Hom., Aleyrodidae)

Zusammenfassung Die Weiße Fliege,Parabemisia myricae (Kuwana) (Hom.: Aleyrodidae), stellt seit ihrer Verschleppung in die Zitrusanbaugebiete an der Südost-Mittelmeerküste der Türkei im Jahre 1982 eines der größten Probleme im dortigen Zitrusanbau dar. Zu ihrer biologischen Bekämpfung wurde im Jahre 1986 der spezifische Parasitoid,Eretmocerus debachi Rose und Rosen (Hym.: Aphelinidae) aus Kalifornien in die Türkei eingeführt. Der Parasitoid konnte sich nach Massenfreilassungen im gesamten Gebiet sehr gut einbürgern. In der vorliegenden Untersuchung wurde die Wirksamkeit vonE. debachi gegenüberP. myricae in zweijährigen Versuchen in natürlich befallenen Zitrusanlagen und auf künstlich infizierten und exponierten Zitrusjungpflanzen erfaßt.Innerhalb von zwei Wochen konnten auf den exponierten Zitrusjungpflanzen die ersten Parasitoiden festgestellt werden, wobei bis zu 10% derP. myricae-Nymphen und Puparien durchE. debachi parasitiert waren. In beiden Versuchsjahren und an allen 4 Standorten baute sich im weiteren Verlauf der Vegetation keine weitere Weiße-Fliegen-Population auf den Zitrusjungpflanzen auf. Die Populationsdichte vonP. myricae war auf den natürlichen befallenen Zitrusbäumen sehr viel geringer als auf den exponierten und künstlich infizierten Pflanzen. Dennoch traten mit den erstenP. myricae auch sofort durchE. debachi parasitierte Individuen auf. Die Parasitierungsrate erreichte teilweise 100%, so daß die Schädlingspopulation sehr schnell im weiteren Vegetationsverlauf abnahm und es zu keiner erneuten Gradation kam. Selbst auf sehr geringe Dichteerhöhungen derP. myricae-Population reagierte der Parasitoid mit einer erhöhten Parasitierung. Die Untersuchungen zeigten deutlich, daßE. debachi in der Lage ist, sowohl sehr hohe als auch sehr niedrige Populationen der Weißen Fliege in hohem Maße zu parasitieren und dadurch den Schädling erfolgreich zu bekämpfen.

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Efficiency ofEretmocerus debachi Rose and Rosen (Hym., Aphelinidae) in controlling the whiteflyParabemisia myricae (Kuwana) (Hom., Aleyrodidae)

The whitefly,Parabemisia myricae (Kuwana) (Hym.: Aleyrodidae) is a most serious problem in citrus since it was accidentally introduced into the Southeast Mediterranean region of Turkey in 1982. To control this pest biologically, the specific parasitoid,Eretmocerus debachi Rose and Rosen (Hym.: Aphelinidae), was imported from California to Turkey in 1986. The parasitoid settled very well after being mass released in the entire citrus growing area. In the present study the efficiencyE. debachi in controllingP. myricae was determined in naturally infested citrus orchards and on potted, artificially infested and exposed citrus seedlings over two years.Within two weeks, the first parasitods were determined on the exposed citrus seedlings at which 10% of theP. myricae-nymphal and-puparial stages were parasitized. In both years and at all four experimental sites no further population increase of the whitefly was observed on the citrus seedling over the entire vegetation period. TheP. myricae-densities were much lower on the naturally infested trees than they were on the exposed and artificially infested citrus seedlings. Nevertheless, the firstE. debachi were observed with the occurrence of the firstP. myricae. The parasitization rate reached sometimes up to 100%, so that the pest population decreased significantly in the following month to almost zero level. Even to smallest population increases ofP. myricae, the parasitoid reacted with increasing parasitization. The experiments proved, thatE. debachi was capable to parasitize high and low population densities of the whitefly completely and in consequence successfully controlled the pest.

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Mit 2 Abbildungen     

Temperature-dependent functional response of two aphid parasitoids, Aphidius colemani and Aphidius matricariae (Hymenoptera: Aphidiidae), on the cotton aphid

The functional response of two aphid parasitoids, Aphidius colemani Viereck and Aphidius matricariae (Haliday) (Hymenoptera: Aphidiidae), on the cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae), was examined. Five constant temperatures (10, 15, 20, 25, and 30°C) and six host densities (2, 4, 8, 16, 32, and 64) were used during a 24-h period. At each temperature, 2–64 third-instar nymphs of A. gossypii were exposed to individual wasp mating pairs. A type II functional response model for both parasitoid wasps was fit separately for each temperature. The results showed that instantaneous attack rate (a) in A. colemani increased linearly as the temperature increases from 10 to 30°C, but in A. matricariae, (a) increased almost linearly with temperature to reach a maximum at 25°C, and then decreased at 30°C, displaying an asymmetrical dome-shaped pattern. The highest instantaneous attack rate for A. colemani and A. matricariae were calculated 0.940 ± 0.144 day⁻¹ at 30°C and 0.687 ± 0.157 day⁻¹ at 25°C, respectively. Handling time (T _h) for A. colemani was inversely proportional to temperature and ranged from 0.093 ± 0.026 day at 10°C to 0.032 ± 0.004 day at 30°C, but in A. matricariae, (T _h) was between 0.078 ± 0.015 day at 10°C and 0.036 ± 0.014 day at 20°C. A. colemani achieved higher parasitism rate than A. matricariae at higher temperatures. This observation suggests that A. colemani maybe more effective for biological control of the cotton aphid during warmer periods.     

Zur Morphologie und Entwicklung von Bracon instabilis Marsh. (Hym., Braconidae), eines Parasiten der Kartoffelmotte,Phthorimaea operculella Zell. (Lep., Gelechiidae) in Ägypten

Bracon instabilis Marshal is an ectoparasite attacking the larvae ofP. operculella in Egypt. According to available literatures, this is the first study onB. instabilis. The laboratory rearing of this parasite was undertaken on the third and fourth larval instars ofP. operculella and the method was mentioned in details. Certain aspects of the morphology of the immature and adult stages were given. The durations of the immature stages of the parasite were estimated at 15 and 25°C and 60±5% R.H. The total durations of the immature stages (from egg to adult) were 39.62 and 11.19 days at 15 and 25°C, respectively.     

Wirkungen von Temperatur und Luftfeuchtigkeit auf die Embryonalentwicklung und das Eischlüpfen bei der SchildzeckeHyalomma marginatum Koch (Acari,Ixodidae)

Effect of temperature and relative humidity on embryonic development and egg hatch ofHyalomma marginatum Koch (Acari, Ixodidae) Effect of different temperatures (25, 30, 35, 40°C) and relative humidity (RH) levels (50, 75, 90%) on embryonic development and hatching ofHyalomma marginatum was investigated. The percentage of dead eggs and embryos, percentage of morphologically normal larvae, percentage of abnormally hatched larvae and percentage of larvae with morphological malformations were determined for each condition. Embryonic development and egg hatch proceeded at 25–35°C in all relative humidity levels tested. However 50% RH was unfavourable for these processes. The optimal conditions for larval development were found to be: temperature of 25–30°C and relative humidity of 75%. Under these conditions 72.7–87.8% of examined egg hatched into normal larvae.     

Host instar suitability of <Emphasis Type="Italic">Bemisia tabaci</Emphasis> (Genn.) (Hom.: Aleyrodidae) for the parasitoid <Emphasis Type="Italic">Eretmocerus mundus</Emphasis> (Hym.: Aphelinidae)

Efficient use of parasitoids in pest control depend on the knowledge of the biological relationships between host and parasitoid. Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae) is one the most important natural enemies of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) that is found in fields and greenhouses in Adana, Turkey. Although more studies have been done to determine the relationships between E. mundus and B. tabaci, the differences among strains of E. mundus could have important biological concequences. In this study, biological characteristics of native population of E. mundus parasitization of B. tabaci (Q biotype) were determined using bean plants Phaseolus vulgaris (L.) at a constant temperature of 25 ± 1°C, relative humidity 70 ± 10% and 16:8 (L:D) photoperiod regimen. All B. tabaci nymphal instars were parasitized by E. mundus, but the mean number of daily-parasitized nymphs was highest in the second instars (15.3). In addition, second instar females had the shortest mean development time (15.2 days). Mean development times of parasitoids obtained from first, second, third and fourth B. tabaci instars varied from 15.2 to 16.2 days and 15.2 to 15.9 days for female and male, respectively. Proportion of female (♀/♂+♀) varied from first (0.53) to second (0.34) host instars. Impact of results on potential biological control of B. tabaci was discussed through conservation native natural enemies.     

Effects of age and host availability on reproduction of <Emphasis Type="Italic">Trioxys angelicae</Emphasis> Haliday (Hymenoptera: Braconidae) parasitizing <Emphasis Type="Italic">Aphis fabae</Emphasis> Scopoli (Hemiptera: Aphididae)

Laboratory studies were conducted to determine the effects of Trioxys angelicae Haliday (Hym.: Braconidae) age and host density (Aphis fabae Scopoli) (Hem.: Aphididae) on selected attributes of parasitoid reproductive biology. The number of hosts parasitized per day was used as an estimate of wasp fecundity. Parasitoid longevity was not affected by host density and at host densities of 2, 4, 6, 8, 10, 15, 20, 30, 40 or 60 aphids per day; the parasitoids lived an average of 8.96 ± 0.82 days at 21°C. At host densities of ≤20 aphids per day, lifetime fecundity of a single Trioxys angelicae female was limited by the number of hosts available. Lifetime fecundity was highest with an average of 158.14 ± 20.33 at a density of 30 aphids per day; the maximum number of aphids parasitized by any female was 235. Daily fecundity and sex ratio were affected by parasitoid age and host density. Age-specific fecundity at different host densities fitted well to a nonlinear model. In conclusion, the fecundity and female progeny production of Trioxys angelicae as an important biological control agent of A. fabae is influenced by host availability.     

Effect of Lecanicillium muscarium on Eretmocerus sp. nr. furuhashii (Hymenoptera: Aphelinidae), a parasitoid of Bemisia tabaci (Hemiptera: Aleyrodidae)

Pathogenicity of Lecanicillium muscarium, against Eretmocerus sp. nr. furuhashii (Hymenoptera: Aphelinidae), was investigated under laboratory conditions to determine if the fungal infection of the whitefly host can effect the survival, longevity and fecundity of female parasitoid. The results indicated that the number of parasitized larvae surviving a L. muscarium treatment after 6 days of oviposition decreased with increasing concentrations of L. muscarium and in later stages of development (12 days post oviposition) were not affected by fungal application. There were no significant differences on adult parasitoid survivorship after 7 days among all treatments. Maximum survivorship (73.33%) was observed for control and it was minimum (60%) at 1 × 10⁸ conidia/ml. L. muscarium showed a non significant effect on longevity and next offsprings of female parasitoids. The percentage emergence of parasitoids from the whitefly nymphs produced by the females emerged from treated pupae was almost similar. Maximum emergence (69.77%) was observed at 1 × 10⁶ conidia/ml and it was lowest (61.02%) at conidial concentration of 1 × 10⁸ conidia/ml. Maximum longevity of adult Eretmocerus sp. emerging from whitefly nymphs when treated after 12 days of postoviposition was observed for 1 × 10⁵ conidia/ml having a mean value of 5 days whereas the lowest longevity was 4.9 days observed at 1 × 10⁸ conidia/ml. The results mentioned above indicate that the interaction among biocontrol agents is positive to a greater extent with minimum risk hazards.     

Reproductive traits and diel activity of adultMonochamus saltuarius (Coleoptera: Cerambycidae) at two different temperatures

To investigate the reproductive traits and diel activity ofMonochamus saltuarius, 14 pairs of the adults were reared and observed at each of 20°C and 25°C. Both sexes were more active at 25°C than at 20°C irrespective of the presence or absence of light. A diel change in behavior during 24 h was found on 33% of a total of 48 observations of three age classes of both sexes. No significant difference was found in the mean longevity between sexes or between the two temperature conditions. The time required for reproductive maturation showed no significant difference within the same sex when reared at 20°C and 25°C. The mean oviposition period was significantly longer at 25°C (28.8 days) than at 20°C (12.2 days). The mean lifetime fecundity was significantly greater at 25°C than at 20°C. There was no significant difference in the oviposition ratio (number of eggs deposited/number of oviposition wounds excavated), oviposition rate or hatchability for females between the two temperature conditions.     

Reduction in egg hatch ofArgas (Argas) reflexus (Fab.) (Acari,Argasidae) due to colchicine

The eggs ofArgas (Argas) reflexus (Fab.) were exposed to 0.05% colchicine on 9th, 15th or 23rd–25th days of embryonic development at 25°C and 30% RH. The eggs on the 15th and 23rd–25th days of development were the most sensitive to colchicine. In these experiments 6.9% and 9.4% embryos died, respectively. The largest number of disturbances of egg hatch (11.5%) were observed after exposure of the eggs to colchicine on 23rd–25th days of embryogenesis.     

Zur Kenntnis der Blattminen-MotteCameraria ohridella Desch. & Dim. (Lep., Lithocolletidae) anAesculus hippocastanum L. in der Tschenchischen Republik

Cameraria ohridella was recorded first in 1985 in Macedonia. It gradually expanded to north and west and at present it is a serious pest of Horse ChestnutAesculus hippocastanum in the Czech Republic, having been established at about 80 localities. There are 4–5 overlapping generations with sizes of the larvae of 0.4–4.0 mm. The larva develops inside the leaf tissue in the upper parenchym layer of the leaflet and causes a mine, the size of which is broadened with growing larva. First adults start to fly at the end of April. After mating the females lay single eggs on the leaves. Larval development lasts 25–30 days followed by the prepupa I and II. The latter spins a cocoon in which the pupa of the last generation hibernates. The development from L4 to the prepupa lasts for 3–6 days at 22°C. During the summer it is possible to find all larval and prepupal stages in attacked leaves. FourAesculus species:A. parviflora Walk,A. carnea Haey.,A. glabra Walk andA. indica J. Hobb. were found to be resistent toC. obridella. A. lutea H. J. was liftle andA. pavia L. was heavily attacked. The parasitization ofC. o. larvae was very low. Only 2 parasites were found in 1500 mines in the first and second generation ofC. o., and 40 parasites in 1000 mines of the fourth and fifth generation. The highest mortality takes place in moths, eggs and young larvae. It was found in all 4 generation that there were i. m. 50 eggs/leaflet from which i. m. 3 hibernating pupae resulted. Supposing 2 moths (1♀, 1♂)/leaflet emerged in spring which produced 50 eggs (75 eggs/♀—33% moth mortality), the density of eggs in the first generation after hibernating being the same as in the last (fourth) generation before hibernating. As to the whole populations density in this case we can calculate as following: 3 pupae/leaflet on the tree=3000 pupae/leaflets pro m² on the soil=2000 emerging moths pro m²=50,000 moths (25,000 ♀♀) pro tree (namely 25 m² projecting area of the tree crown×2000 moths).      

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.     

Zur Biologie von Trogoderma variabile Ball. (Coleopt., Dermestidae): Lebensdauer der Imagines und Eiablage

Distribution and economic importance of the dermestid beetleTrogoderma variabile are quoted and the possibility of an introduction into Europe is stated. Hence the biology ofT. variabile shall be examined in detail. In this paper the author refers longevity of the adults at different temperatures (25, 30, 35 °C) and the number of eggs laid per female.     

Biological characteristics and life tables of Neoseiulus umbraticus Chant (Acari, Phytoseiidae) at three constant temperatures

The development time, survival and fecundity of the generalist predatory mite, Neoseiulus umbraticus Chant, were determined at 20, 25, and 30?°C and 65?±?10?% RH. N. umbraticus females completed development in 9.7, 8.0 and 5.9 days, respectively, using a diet of all life stages of Tetranychus cinnabarinus Boisduval. Total developmental times of males were relatively shorter at 25 and 30?°C than at 20?°C. In general, preoviposition, oviposition, and postoviposition periods of N. umbraticus shortened as temperature increased. The longest survival rate of N. umbraticus of 80.5 days occurred at 20?°C, followed by 67.0 and 57.6 days at 25 and 30?°C, respectively. Mated females laid an average 0.9, 1.3 and 1.4 eggs per female per day and 33.1, 44.0 and 43.6 eggs over their entire lives at 20, 25 and 30?°C, respectively. The sex ratios of this species were 0.57, 0.57 and 0.54 female (female+male) at 20, 25 and 30?°C, respectively. The intrinsic rate of increase (r_m) became greater with rising temperatures from 0.123 at 20?°C to 0.180 at 30?°C. The net reproduction rate (R_o) was highest at 25?°C (25.0 females/female) and lowest at 20?°C (18.8 females/female), while T_o decreased with increasing temperatures, from 23.8 days at 20?°C to 17.5 days at 30?°C.