Effect of Temperature on the Life History of Cirrospilus sp. near lyncus (Hymenoptera: Eulophidae), a Parasitoid of Phyllocnistis citrella (Lepidoptera: Gracillariidae)

The effect of four constant temperatures on the life history of Cirrospilus sp. near lyncus was examined in the laboratory. This species is one of the most abundant generalist indigenous parasitoids of the citrus leafminer, Phyllocnistis citrella Stainton, in Spain. Adult lifespan of C. sp. near lyncus decreased from 50.2 to 9.1 days as temperatures increased from 15 to 30°C, respectively. Both gross fecundity and host-feeding were highest at 20°C (170.48 eggs and 32.33 hosts). Oviposition rates were optimal at higher temperatures (5.22 eggs per day at 25°C and 4.79 eggs per day at 30°C) and were dependent on female age. In contrast, host-feeding rates for a given temperature did not depend on age. Generation time decreased with increasing temperatures from 68.05 days at 15°C to 12.19 days at 30°C. Net reproduction peaked at 20°C (68.86 viable females per female). Intrinsic rate of increase doubled from 15°C (0.059 females per female per day) to 20°C (0.127 females per female per day) and almost doubled again from 20 to 30°C (0.210 females per female per day). Given these parameters, C. sp. near lyncus could perform optimally in the area occupied by P. citrella in the Mediterranean region.     

Life tables of the predatory mite Phytoseiulus longipes feeding on Tetranychus evansi at four temperatures (Acari: Phytoseiidae, Tetranychidae)

The tomato red spider mite, Tetranychus evansi, is reported as a severe pest of tomato and other solanaceous crops from Africa, from Atlantic and Mediterranean Islands, and more recently from the south of Europe (Portugal, Spain and France). A population of the predaceous mite Phytoseiulus longipes has been recently found in Brazil in association with T. evansi. The objective of this paper was to assess the development and reproduction abilities of this strain on T. evansi under laboratory conditions at four temperatures: 15, 20, 25 and 30°C. The duration of the immature phase ranged from 3.1 to 15.4 days, at 30 and 15°C, respectively. Global immature lower thermal threshold was 12.0°C. Immature survival was high at all temperatures tested (minimum of 88% at 30°C). The intrinsic rate of increase (r _m) of P. longipes ranged from 0.091 to 0.416 female/female/day, at 15 and 30°C, respectively. P. longipes would be able to develop at a wide range of temperatures feeding on T. evansi and has the potential to control T. evansi populations.     

Reproduction,longevity and life table parameters of <Emphasis Type="Italic">Tyrophagus neiswanderi</Emphasis> (Acari: Acaridae) at constant temperatures

The astigmatid mite Tyrophagus neiswanderi Johnston and Bruce is mainly considered a pest of ornamental and horticultural crops. However, this mite has been found infesting Cabrales cheese in Spain, though its population density is low compared to Acarus farris, the prevalent species of astigmatid mite encountered in Cabrales cheese maturing caves. One of the factors that might be influencing this differential abundance is temperature. In the present study the effect of temperature on reproductive parameters and longevity of T. neiswanderi was examined at six constant temperatures, ranging from 10 to 31°C, and a relative humidity of 90 ± 5%. Preoviposition period, fecundity and daily fecundity were adversely affected by extreme temperatures while the oviposition period increased as temperature was reduced. Male and female longevity increased as temperature decreased, but males showed significantly greater longevity than females. Additionally, this difference was greater as temperature decreased. The effect of temperature on the intrinsic rate of natural increase of T. neiswanderi populations was described by the non-linear Lactin model. The optimum temperature for development was predicted at 26.6°C. At this temperature, the population doubling time is 2.8 days. The lower and upper thresholds for T. neiswanderi populations were calculated at 7.4 and 31.7°C, respectively. According to these results, the influence of temperature on the low population density of this mite found in Cabrales maturing caves compared with A. farris is discussed.     

Effect of temperature on the life history of <Emphasis Type="Italic">Eretmocerus</Emphasis> sp. nr. <Emphasis Type="Italic">furuhashii</Emphasis>, a parasitoid of <Emphasis Type="Italic">Bemisia tabaci</Emphasis>

Eretmocerus sp. nr. furuhashii (Hymenoptera: Aphelinidae) is an indigenous parasitoid of Bemisia tabaci (Gennadius)(Hemiptera: Aleyrodidae) from southern China; the effects of constant temperatures on the life history of E. sp. nr. furuhashii were examined in the laboratory. The developmental period ranged from 39.2 days at 20°C to 12.40 days at 32°C. A total of 263.4 degree-days were required to complete development with a lower developmental threshold temperature of 11.1°C. Of the eggs produced, 59.3% completed development at 20°C with completion increasing to 71.5% at 26°C. Adult female longevity was 10.8 days at 20°C and 5.2 days at 32°C while the mean daily offspring reproduced per female was highest at 29°C with 5.9 offspring. Adult oviposition peaked three days after emergence at 26, 29 and 32°C, and four days post-emergence at 20°C and 23°C. The total numbers of offspring produced per female ranged from 25.7 individuals at 32°C to 41.1 individuals at 20°C. The sex ratio had a female bias and ranged from 0.72 at 17°C to 0.51 at 35°C. The intrinsic rate of increase was 0.1727 at 29°C followed with 0.1606 at 32°C. Results indicated that E. sp. nr. furuhashii reaches its maximum biological potential at temperatures ranging from 26°C to 32°C.     

Reproduction of three eulophid wasps that parasitise larvae of the citrus leafminer

The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) (CLM), is a citrus pest indigenous to Southeast Asia. It was discovered in Israel in 1994. The pest attacks the young foliage of citrus, and damage is caused by the larvae tunnelling under the epidermis of young leaves, leading to foliage destruction. The present study documents basic biological parameters of three exotic eulophid wasps in the laboratory: Semielacher petiolatus, Quadrastichus citrella and Teleopterus sp. S. petiolatus females preferred to lay eggs in the 3rd larval instar of CLM, but did not lay eggs in the 1st instar. Its development ranged from 9 to 14 days. Female longevity was 30.2±5.9 days, its daily oviposition was 12.16±0.68 eggs/day, the total number of eggs oviposited per female was 278.9±74.1, and the number of CLM larvae parasitised was 260.0±68.3. Q. citrella preferred to lay in the 3rd and 4th instar larvae, but not in the 1st instar, its development ranged from 9 to 14 days, female longevity was 40.6±1.9 days, oviposition came to 8.3±0.6 eggs/day, the total number of eggs oviposited was 281.3±64.9/female and the number of parasitised CLM larvae was 276.5±63.7. Teleopterus sp. preferred to lay eggs in the 3rd larval instar, its development required 11–17 days, female longevity was 28.7±3.8 days, its daily number of offspring was 5.2±0.38 offspring/day and with emergence of 138.9±27.7 offspring/female. This knowledge enabled us to maintain high quality cultures for their releases in Israel.     

Seasonal changes in daily torpor patterns of free-ranging female and male Daubenton’s bats (Myotis daubentonii)

Daily torpor can provide significant energy and water savings in bats during cold ambient temperatures and food scarcity. However, it may reduce rates of foetal and juvenile development. Therefore, reproductive females should optimize development by minimizing times in torpor. To test this hypothesis, the use of torpor by female and male free-ranging Daubenton’s bats (Myotis daubentonii) during reproduction (gestation, lactation, and post-lactation period) was investigated in 1998 and 1999. Temperature-sensitive radio transmitters were attached to the bats to measure skin temperature. Simultaneously, ambient temperature was recorded. While both sexes became torpid during daytime, male bats used daily torpor (>6°C below individual active temperature) significantly more often during reproductive period (mean: 78.4 % of day time in May and 43 % in June) than females. Female bats went into daily torpor, particularly in late summer when juveniles were weaned (mean: 66.6 % of daytime). Lowest skin temperatures occurred in a female bat with 21.0°C during post-lactation. Skin temperatures of male bats fluctuated from 16.8°C in torpor to 37.2°C during times of activity. There was a significant effect of reproductive period on skin temperature in females whereas mean ambient temperature had no significant effect. However, mean ambient temperature affected mean skin temperatures in males. Our findings indicate that female Daubenton’s bats adopt their thermoregulatory behaviour in particular to optimize the juvenile development.     

Biological studies withChrysocharis parksi [Hym.: Eulophidae] a parasite ofLiriomyza spp. [Dipt.: Agromyzidae]

Biological studies withChrysocharis parksi Crawford, a parasite of agromyzid leafminers, were conducted.C. parksi successfully parasitized the following species in the genusLiriomyza Mik.,L. huidobrensis (Blanchard),L. sativae Blanchard,L. trifolii (Burgess), andL. trifoliearum Spencer. Successful parasite development was recorded from 8 plant families and 16 genera. Host plants which were suitable for leafminer development to the adult stage were also suitable for parasite development. Mean immature developmental period (egg to adult, usingL. trifolii as the host) at 21.1°, 26.7°, and 32.2° C was (for both sexes) 23, 14, and 14 days, respectively. Longevity of females provided only water was inversely related to temperature; significantly longer survival occurred at 21.1° C (5.0 days) compared to 26.7° C and 32.2° C (3.2 and 2.1 days, respectively). The addition of honey to the diet significantly improved longevity of both sexes at all temperatures. Adult female parasites which were provided an average of 33.0L. trifolii larvae per day produced an average of 135 offspring at a constant 26.7° C.C. parksi host-fed on ca. 3.7 leafminer larvae per day over an 11-day adult lifespan.      

Temperature dependence for development of the whitefly predator <Emphasis Type="Italic">Clitostethus arcuatus</Emphasis> (Rossi)

This work aimed to study the biology of Clitostethus arcuatus (Rossi) (Coleoptera: Coccinellidae) under different temperatures and evaluate the optimum temperature for its mass rearing. Studies were carried out in the laboratory at four constant temperatures (15°C, 20°C, 25°C and 30°C), 75 ± 5% relative humidity and a photoperiod of 16 h light:8 h dark, in which C. arcuatus was fed ad libitum with nymphs of all instar of Aleyrodes proletella L. (Homoptera: Aleyrodidae) on Brassicae oleracea L. (var. Costata). The following biological parameters were evaluated: development time and survival rates of pre-imaginal stages, adult longevity (female and male), length of the pre-oviposition and oviposition periods, fecundity, fertility and percentage of egg hatching. Population growth parameters, the lower development threshold and the sum of effective temperatures were estimated. Temperatures ranging from 20°C to 30°C were suitable for the development of C. arcuatus, suggesting that this species is well adapted to the temperatures usually found inside greenhouses or in open fields in temperate regions. Although the intrinsic rate of natural increase and doubling time were similar at 25°C and 30°C, the temperature of 25°C was shown to be the most suitable for mass rearing and development of populations under field conditions, since the percentage of egg hatching and the accumulated survival rates of the pre-imaginal stages were the highest. Considering the estimated lower threshold for pre-imaginal development (7.9°C) and the sum of effective temperatures [293.6 degree-days (°D)], it is predicted for Ponta Delgada (Azores, Portugal) that the first adults of C. arcuatus should emerge by the first fortnight of February and that up to 12 generations per year can occur.     

Effect of temperature on the development, fecundity, progeny sex ratio and life-table of Campoletis chlorideae, an endolarval parasitoid of the pod borer, Helicoverpa armigera

Development, survival, fecundity, progeny sex ratio (PSR) and age-specific life-table parameters of the parasitoid Campoletis chlorideae Uchida (Hymenoptera: Ichneumonidae) were examined at six different constant temperatures (12, 17, 22, 27, 32 and 37°C) in the laboratory [70 ± 10% RH and 10:14 h (light:dark) photoperiod]. Second instar larvae of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) were reared on chickpea (Cicer arietinum L.) and used as the host. Development times shortened as the temperature increased from 12 to 37°C. The estimated lower developmental threshold (tL) was 3.4°C. The thermal summation for total immature stages was 379.97 degree-days. A reciprocal relationship between temperature and longevity was observed in the range of 12–17°C. The maximum mortality of pupae (71.8%) occurred at 37°C. At 22°C, the yield of a female parasitoid averaged 137.3 ± 14.7 (mean ± SD) progeny, of which 89.6 ± 7.6 were daughters. The number of daughters produced decreased when the females were kept either above or below 22°C, although the PSR was female biased in the range of 17–27°C. The analyses of life-table parameters, developmental rates, reproduction, mortality and PSR suggest that maximum population growth (r _m ) is near 27°C. There was little variation observed in most of the desired qualities of C. chlorideae in the range of 17–27°C, and it appears that the parasitoid is adapted to a wide range of temperatures. We suggest that for maximum production the parasitoid should be reared at 22 ± 4°C and be released in areas where the temperature ranges between 17° and 27°C, as in the plains of northern India.     

Natural mortality factors acting on citrus leafminer, Phyllocnistis citrella, in lime orchards in South Florida

Seasonal mortality of the citrusleafminer, Phyllocnistis citrellaStainton, was studied from 1994 through 1998 in`Tahiti' lime, Citrus aurantifolia (Christm.) Swingle,in Homestead, Florida. Survival of eachdevelopmental host stage and the proportionattacked by indigenous and introduced naturalenemies were determined. Before the recovery ofthe introduced parasitoid, Ageniaspiscitricola Logvinovskaya, in 1995, thethird-instar host had the highest averageproportion of parasitized individuals (0.14)followed by the prepupa (0.11) while the firstinstar had the lowest proportion parasitized(0.02). After the first recovery andestablishment of A. citricola, theproportion of pupae parasitized increased to0.56 followed by the prepupa (0.14) and thethird instar (0.11). Before the introduction ofA. citricola, the highest proportion ofhosts killed by predation was observed insecond instar (0.17) and third instar (0.15).After the establishment of the introducedspecies, the proportion of dead individuals dueto predation was greater for second instar(0.31) and third instar (0.21) larvae.Mortality caused by indigenous natural enemieswas significantly correlated with increases ofP. citrella density. Parasitism ofP. citrella by the exotic parasitoid,A. citricola, correlated less well to hostdensity over the season (r² = 0.12) thandid mortality caused by indigenous naturalenemies (r² = 0.76). Moreover, a higherpercent mortality in population of P. citrellawas obtained from predation by theindigenous natural enemies than the introducedparasitoid as shown in the mortality estimatesfrom 1995 to 1998.     

Effect of temperature on development rate and intrinsic rate of increase ofAphis gossypii reared on greenhouse cucumbers

Thermal requirements for development and life table statistics ofAphis gossypii Glover (Homoptera, Aphididae) were determined over a range of constant temperatures from 10 to 30°C. The lower development threshold and the sum of effective temperatures were 6.9°C and 90.1°C, respectively, for preimaginal development, and 5.8°C and 113.6°C from birth to the onset of reproduction. Mean total fecundity ranged from 36 larvae per female at 10°C to 76 larvae at 30°C. On a time scale of days, net reproductive rate (R _o ) increased with increasing temperature while generation time (T) decreased causing the intrinsic rate of increase (r _m ) to increase linearly from 0.115 to 0.465. On a day-degree scaler _m only varied from 0.019 to 0.028 because the growth ofR _o was compensated by an increase inT with increase in temperature. The nearly constantr _m in terms of day-degrees, over a wide range of temperatures, greatly simplifies the prediction of future population numbers ofA. gossypii.     

Uscana lariophaga, egg parasitoid of bruchid beetle storage pests of cowpea in West Africa: the effect of temperature and humidity

The stored-product bruchid pests,Callosobruchus maculatus (Fabricius) andBruchidius atrolineatus (Pic) cause considerable production losses in cowpea in West Africa.Uscana lariophage Steffan parasitizes the eggs of the bruchids both in the field and in storage. As chemical control of bruchids in traditional granaries is not appropriate for poor farmers, enhancement of the efficacy of the parasitoid by environmental manipulation has been investigated. The effect of temperature on the capacity ofU. lariophaga to parasitize eggs has been studied at eleven constant and three fluctuating temperatures within the range 10 to 45°C. Longevity of the female wasp decreased with increasing temperature. The rate of development increased linearly at temperatures from 17.5 to 35°C, but decreased from 35 to 40°C. Mortality of the developing wasp remained below 20% from 20 to 37.5°C, but outside this range, mortality reached 100% at 15 at 42.5°C. Most parasitization occurred at temperatures of 25 and 30°C. Sex ratio (percentage females) increased with temperature in the high temperature range. The intrinsic rate of increase (r_m) forU. lariophaga was highest in the temperature range from 30 to 37.5°C and was higher than that ofC. maculatus at all temperatures. While the r_m value ofC. maculatus did not vary much at temperatures from 25 to 35°C, the r_m value of the wasp doubled. Relative humidity did not effect longevity, egg-laying capacity, mortality, development time and sex ratio of the wasps withC. maculatus as host. However, withB. atrolineatus as the host, development time and mortality increased at lower relative humidity levels. The results indicate that temperature is the major regulating factor on the parasitoid. As the type of storage structure and its location (sun or shade) affects the temperature inside the store, ways are being investigated of manipulating the storage environment through temperature regulation to increase the impact of the parasitoid.     

Temperature-dependent development and reproductive traits of <Emphasis Type="Italic">Tetranychus macfarlanei</Emphasis> (Acari: Tetranychidae)

Development and reproductive traits of Tetranychus macfarlanei Baker & Pritchard (Acari: Tetranychidae) were investigated on kidney bean, Phaseolus vulgaris L., at eleven constant temperatures. Tetranychus macfarlanei was able to develop and complete its life cycle at temperatures ranging from 17.5 to 37.5°C. At 15 and 40°C, a few eggs (2–4%) hatched but further development was arrested. Development from egg to adult was slowest at 17.5°C and fastest at 35°C for both females and males. Using Ikemoto and Takai’s linear model, the estimated lower developmental thresholds for egg-to-female adult, egg-to-male adult and egg-to-egg development were 12.9–13.0°C. The thermal constants for the respective stages were 110.85, 115.99 and 125.32 degree-days (DD). The intrinsic optimum temperatures (T _Φ) calculated by non-linear SSI model were determined as 24.4, 24.4 and 24.2°C for egg-to-female adult, egg-to-male adult and egg-to-egg development, respectively. The net reproductive rate (R ₀) was highest at 25°C (167.4 females per female) and lowest at 17.5°C (42.6 females per female). The intrinsic rate of natural increase, r _m, increased linearly with the rising of temperature from 0.102 at 17.5°C to 0.441 day⁻¹ at 35°C. These values suggested that T. macfarlanei could be growing quickly in response to increasing temperatures from 17.5 to 35°C and provide a basis for predicting its potential geographical range.     

Bionomics of a polyphagous predator:Orius laevigatus (Het.: Anthocoridae)

The main characteristics of the imaginal and preimaginal development and the reproduction ofOrius laevigatus were studied at 15, 20, 25 and 30°C. Temperature greatly influences the developmental and reproductive biology of this species. The lowest developmental threshold is 10,6°C. Reproduction is greatly reduced at 15°C relative to the higher temperatures tested. O. laevigatus is well adapted to relatively high temperature conditions. The best development and reproduction rates are observed between 20 and 30°C with a theoretical optimum at 26°C.

---

Résumé Les principales caractéristiques du développement pré-imaginal et imaginal ainsi que la reproduction d'Orius laevigatus sont étudiées à des températures de 15, 20, 25 et 30°C. La température influence considérablement le développement embryonnaire et post-embryoannaire de cette espèce. Le zéro théorique de développement se situe à 10,5°C. Les capacités reproductrices sont fortement perturbées à des températures inférieures à 15°C. Les résultats montrent queO. laevigatus est une espèce adaptée à des conditions thermiques relativement élevées. C'est entre 20 et 30°C, avec un optimum de 26°C, que s'expriment le mieux les capacités de développement et de reproduction de ce prédateur.

     

Life history of the predatory mite <Emphasis Type="Italic">Phytoseiulus fragariae</Emphasis> on <Emphasis Type="Italic">Tetranychus evansi</Emphasis> and <Emphasis Type="Italic">Tetranychus urticae</Emphasis> (Acari: Phytoseiidae,Tetranychidae) at five temperatures

Tetranychus evansi Baker and Pritchard and Tetranychus urticae Koch (Acari: Tetranychidae) are important pests of Solanaceae in many countries. Several studies have demonstrated that T. urticae is an acceptable prey to many predatory mites, although the suitability of this prey depends on the host plant. T. evansi, has been shown to be an unfavorable prey to most predatory mites that have been tested against it. The predator Phytoseiulus fragariae Denmark and Schicha (Acari: Phytoseiidae) has been found in association with the two species in Brazil. The objective of this work was to compare biological parameters of P. fragariae on T. evansi and on T. urticae as prey. The study was conducted under laboratory conditions at 10, 15, 20, 25 and 30°C. At all temperatures, survivorship was lower on T. evansi than on T. urticae. No predator reached adulthood at 10°C on the former species; even on the latter species, only about 36% of the predators reached adulthood at 10°C. For both prey, in general, duration of each life stage was shorter, total fecundity was lower and intrinsic rate of population increase (r _m ) was higher with increasing temperatures. The slower rate of development of P. fragariae on T. evansi resulted in a slightly higher thermal requirement (103.9 degree-days) on that prey than on T. urticae (97.1 degree-days). The values of net reproduction rate (R ₀), intrinsic rate of increase (r _m ) and finite rate of increase (λ) were significantly higher on T. urticae, indicating faster population increase of the predator on this prey species. The highest value of r _m of the predator was 0.154 and 0.337 female per female per day on T. evansi and on T. urticae, respectively. The results suggested that P. fragariae cannot be considered a good predator of T. evansi.     

Bionomics of the acarophagous ladybird beetle Stethorus tridens fed Tetranychus evansi

The bionomics of Stethorus tridens Gordon fed Tetranychus evansi Baker & Pritchard were studied in the laboratory. The number of prey consumed by S. tridens increased with increasing instar levels and the total mean number consumed during immature development was 184.1 ± 18.02 T. evansi nymphs per individual. For adult male and adult female, the daily consumption was 41.3 ± 0.80 and 67.8 ± 1.69 nymphs, respectively. Stethorus tridens successfully developed to adulthood between 20 and 30°C but failed at 10, 15 and 35°C. The lower thermal threshold for egg‐to‐adult development estimated via linear regression and the modified Logan model was 9.2 and 8.1°C, respectively. The optimum and maximum temperatures for egg‐to‐adult development were around 29–31 and 32.9°C, respectively. Egg to adult development time was 23.8 ± 0.24, 17.4 ± 0.22, 16.2 ± 0.22 and 12.1 ± 0.16 days at 20, 24, 27 and 30°C, respectively. At 27°C, the sex ratio, expressed as the proportion of females, was 0.54 and the mean preoviposition, oviposition and postoviposition periods were 10.3 ± 0.67, 31.2 ± 4.74 and 30.2 ± 5.24 days, respectively. The oviposition rate was 4.0 ± 0.16 eggs/female/day with a female mean longevity of 71.6 ± 6.19 days and an intrinsic rate of natural increase of 0.104. The potential of S. tridens as a candidate natural enemy of T. evansi is discussed.     

Effect of Temperature on Development and Fecundity of the Predaceous Plant Bug <Emphasis Type="Italic">Deraeocoris brevis</Emphasis> Reared on <Emphasis Type="Italic">Ephestia kuehniella</Emphasis> Eggs

Temperature-dependent development and oviposition component models were developed for Deraeocoris brevis (Uhler) (Hemiptera: Miridae). Egg development times decreased with increasing temperature and ranged from 35.8 d at 15 °C to 6.7 d at 32 °C. Total development times of nymphs reared on frozen Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) eggs decreased from an estimated 55.6 d at 15 °C to 9.2 d at 32 °C and 10.0 d at 34.6 °C. By fitting linear models to the data the lower developmental threshold temperatures for eggs, small nymphs (1st to 3rd instar), large nymphs (4th to 5th instar), and all nymphs combined were calculated as 10.5, 12.5, 11.8, and 11.9 °C, respectively. The thermal constants were 144.1, 90.3, 95.0, and 190.8 degree-days for each of the above stages. The non-linear model was based on a Gaussian equation, which fit the relationship between development rate and temperature well for all stages. The Weibull function provided a good fit for the distribution of development times of each stage. Adult longevity decreased with increasing temperature and ranged from 52.9 d at 21.7 to 16.8 d at 32.0 °C. D. brevis had a maximum fecundity of 471 eggs per female at 24 °C, which declined to 191 eggs per female at 32 °C. Also, three temperature-dependent components for an oviposition model of D. brevis were developed including models for total fecundity, age-specific cumulative oviposition rate, and age-specific survival rate.     

Life history parameters for Nesidiocoris tenuis (Reuter) (Het., Miridae) under different temperature regimes

The development time for eggs and nymphs and female fertility were determined for Nesidiocoris tenuis Reuter (Het., Miridae: Dicyphini) at 15, 20, 25, 30, 35 and 40 ± 1°C, using tomato, Solanum esculentum (Miller), as substrate and eggs of Ephestia kuehniella Zeller as substitute prey. At 40°C, N. tenuis was unable to develop and barely reproduced. Egg development ranged from 30.8 days at 15°C to 6.3 days at 35°C. The cumulative thermal requirements for the eggs were 148.6 degree days (°d) and the lower thermal threshold, 10.3°C. The duration of the nymphal instar decreased from 55.9 days at 15°C to 8.6 days at 35°C. The thermal constant for the nymphs was 182.3 °d and the lower thermal threshold 11.7°C. No nymphs survived at 40°C, and the highest mortalities were at extreme temperatures (15 and 35°C). Female and male weights were influenced significantly by temperature. The fertility of N. tenuis females was reduced greatly at 15 and 40°C. The highest fertility during an observation period of 18 days following female emergence (79.5–60.0 nymphs per female) was within the temperature range of 20 to 35°C. Fertility was related directly to female weight and temperature (r² = 0.932). Based on development, reproduction data and thermal requirements, the optimum temperature range for N. tenuis was established as being between 20 and 30°C. Overall, N. tenuis is the most thermophilous of all dicyphines from vegetable crops in the Mediterranean area studied so far.     

The progeny production of a hymenopterous parasitoid,Apanteles sp. groupultor,as affected by temperature

Adults of the parasiteApanteles sp. groupultor were held unter constant temperatures (15, 20, 26, 30°C) each within ±1°C. Total progeny production was significantly greater at 26°C, averaging 85 per female and decreased at 15°C and 30°C. Mating behavior showed that both sexes were a polygamous. The range of constant temperature did not greatly alter the progeny sex ratio when female parent had been mated. At 15°C, male activity was adversely affected when both sexes were exposed to it without previous mating, resulting in a higher number of male progeny. A temperature of 26°C was the most appropriate for normal sex ratio.      

Biology ofMicroplitis mediator [Hym.: Braconidae] a gregarious endoparasite ofAgrotis segetum [Lep.: Noctuidae]

Microplitis mediator (Haliday) a gregarious endoparasite was recorded for the first time fromAgrotis segetum (Schiff) in Ankara, Turkey. The female parasites found their hosts by responding to the faeces of the caterpillars. An average, females laid 15.5±1.6 eggs in the bodies of their hosts. The newly laid eggs were elongated, oval in shape and 0.23±0.004 mm long and 0.07 mm wide. They hatched in 5, 4 and 3 days at 20±2°C, 25±2°C and 30±2°C respectively when maintained at 60–70% R.H. and 14∶10 light∶dark regime. At the same temperatures, the larval stage lasted for 24.9±0.6, 18.2±0.4 and 17.1±0.5 days respectively. The prepupal stage was completed in 2 days at 25±2°C, whereas the prepupal and pupal (cocoon) stage lasted 10.9±0.2, 7.0±0.1 and 6.2±0.1 days respectively at the temperatures mentioned above. The adults started mating and feeding shortly after emergence. Female parasites started laying after one day, 7–11 hours and 5–7 hours at the temperatures stated above. At these temperatures females lived for 10.8±0.2, 5.4±0.1, 4.6±0.1 days and laid on average 556, 484 and 363 eggs respectively, whereas the males survived 10.5±0.3, 4.7±0.1 and 4.4±0.1 days respectively.