Influences of temperature and humidity on the life history parameters and prey consumption of <Emphasis Type="Italic">Anthocoris minki</Emphasis> Dohrn (Heteroptera: Anthocoridae)

Anthocoris minki Dohrn is a promising indigenous Anthocoris species for the biological control of Agonoscena pistaciae Burck. and Laut. (Homoptera: Psyllidae) in pistachio orchards in Turkey. The adult longevity, fecundity, life table parameters and prey consumption of A. minki fed on Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs were studied at combinations of three constant temperatures (20, 25 and 30 ± 1°C) with two relative humidity (RH) levels (40 and 65 ± 5%). Studies indicated that temperature and RH significantly affected adult longevity, fecundity and prey consumption of A. minki. The greatest adult female longevity was 116.0 days at 20°C and 65% RH; the shortest adult female longevity was 27.5 days at 30°C and 40% RH. At all tested temperatures, the oviposition period and prey consumption of both females and males significantly decreased at low RH compared to high RH. The highest and lowest total fecundities were 276.0 eggs (at 20°C and 65% RH) and 42.4 eggs (at 25°C and 40% RH), respectively. The intrinsic rates of natural increase (r _m) at 40 and 65% RH were 0.049 and 0.076 at 20°C, 0.072 and 0.096 at 25°C and 0.076 and 0.112 at 30°C, respectively. The highest mean numbers of E. kuehniella eggs consumed by females and males were 859.6 (at 20°C) and 515.3 (at 25°C) at 65% RH, respectively; the lowest were 183.3 (at 20°C) and 95.5 (at 25°C) at 40% RH, respectively.     

Effects of temperature on biology and life table parameters of the Asian citrus psyllid, Diaphorina citri Kuwayama (Homoptera: Psyllidae)

The development, survivorship, longevity, reproduction, and life table parameters of the Asian citrus psyllid, Diaphorina citri Kuwayama were evaluated at 10°C, 15°C, 20°C, 25°C, 28°C, 30°C and 33°C. The populations reared at 10°C and 33°C failed to develop. Between 15°C and 30°C, mean developmental period from egg to adult varied from 49.3 days at 15°C to 14.1 days at 28°C. The low‐temperature developmental thresholds for 1st through 5th instars were estimated at 11.7°C, 10.7°C, 10.1°C, 10.5°C and 10.9°C, respectively. A modified Logan model was used to describe the relationship between developmental rate and temperature. The survival of the 3rd through 5th nymphal instars at 15–28°C was essentially the same. The mean longevity of females increased with decreasing temperature within 15–30°C. The maximal longevity of individual females was recorded 117, 60, 56, 52 and 51 days at 15°C, 20°C, 25°C, 28°C and 30°C, respectively. The average number of eggs produced per female significantly increased with increasing temperature and reached a maximum of 748.3 eggs at 28°C (P<0.001). The population reared at 28°C had the highest intrinsic rate of increased (0.199) and net reproductive rate (292.2); and the shortest population doubling time (3.5 days) and mean generation time (28.6 days) compared with populations reared at 15–25°C. The optimum range of temperatures for D. citri population growth was 25–28°C.     

Temperature effects on the development and fecundity of <Emphasis Type="Italic">Encarsia acaudaleyrodis</Emphasis> (Hymenoptera: Aphelinidae), a parasitoid of <Emphasis Type="Italic">Bemisia tabaci</Emphasis> (Homoptera: Aleyrodidae) on cucumber

Development, reproduction, and life table parameters of the parasitoid Encarsia acaudaleyrodis Hayat parasitizing Bemisia tabaci Gennadius were studied at constant temperatures in the range of 20–32°C under laboratory conditions. Egg-to-adult developmental time decreased from 20.3 days at 20°C to 9.0 days at 32°C. An average of 189.8 day-degrees was required to complete development above the lower threshold temperature (11.5°C). Juvenile survival was 84, 88, 70 and 69% at 20, 25, 30 and 32°C, respectively. Females of E. acaudaleyrodis oviposited means of 34.2, 54.6, 30.6 and 20.1 eggs at 20, 25, 30 and 32°C, respectively, and had a mean longevity of 21.1, 14.7, 10.0 and 9.1 days at the same four temperatures. The intrinsic rate of population increase (r_m) at the different temperatures ranged from 0.082 to 0.169, with the highest value recorded at 25°C. These data indicate that E. acaudaleyrodis may be better adapted to intermediate temperatures around 25°C and, therefore, could be a useful biological control agent of B. tabaci during spring and autumn when such temperatures are prevalent in Southwestern of Iran. The result could also be useful in developing a population model for E. acaudaleyrodis under field conditions.     

Life table and heat tolerance of Acyrthosiphon pisum (Hemiptera: Aphididae) in subtropical Taiwan

The effect of temperature on the life table of Acyrthosiphon pisum reared on Pisum sativum was evaluated under laboratory conditions using temperatures of 10, 15, 20, 25, 30, and 35°C. The development time of juvenile A. pisum decreased with increasing temperature (from 21.3 days at 10°C to 4.7 days at 35°C). Adult longevity also decreased with increasing temperature (from 53.2 days at 10°C to 2.3 days at 35°C). Interestingly, 70% and 25% of A. pisum nymphs reared at 30°C and 35°C, respectively, successfully developed into adults. These temperatures have previously been considered unsuitable for A. pisum development. However, adult aphids reared at 30°C and 35°C failed to reproduce. Linear regression analysis revealed that the lower development threshold of A. pisum was 153.1 degree‐days above 1.9°C. Maximal average reproductive capability was observed at 10°C for A. pisum adults, with each adult producing more than 120 nymphs. The intrinsic rate of increase (r_m) of A. pisum increased from 0.124/day at 10°C to 0.337/day at 25°C, whereas opposite trends were observed for the net reproductive rate (R₀) and the mean generation time (GT). At 20°C and 25°C, the intrinsic rate of increase of A. pisum was significantly higher than at 10°C and 15°C (P < 0.0001), indicating that 20°C and 25°C are within the optimal range for the growth of A. pisum, and that 30°C is beyond the upper threshold limit for reproduction, which involves a temperature range that is narrower than that of the survival range (upper limit is unknown, but above 35°C).     

Life table parameters of an indigenous strain of Neoseiulus californicus McGregor (Acari: Phytoseiidae) when fed Tetranychus urticae Koch (Acari: Tetranychidae)

The life table of the indigenous Neoseiulus californicus was studied at different temperatures and 65 ± 5% relative humidity under conditions of 16 h light : 8 h dark (LD 16:8). The total developmental period from egg to adult varied from 3.0 to 14.0 days at 15 to 35°C. Survival to adulthood ranges from 86.21 to 93.94%, with the highest rate at 25°C. The lower threshold temperature from egg to adult stages of females and males was 10.84 and 10.72°C, respectively, and the thermal constant was 57.14 degree‐days (DD) for females and 56.18 DD for males. Total number of eggs laid by each female was the highest (70.38 eggs) at 25°C, whereas average daily fecundity was the highest (3.69 eggs/female/day) at 30°C. The net reproductive rate was the highest (48.49) at 25°C and lowest (26.18) at 30°C. Mean generation time decreased from 19.04 to 11.47 days with increasing temperature from 20 to 30°C. Both intrinsic rate of natural increase (0.284) and finite rate of increase (1.32) were maximum at 30°C. Adult longevity was the highest (42.75 days for females and 32.60 days for males) at 20°C and lowest (22.70 days for females and 15.30 days for males) at 30°C. Sex ratio was female biased and was the highest (78.08) at 25°C and lowest (70.24) at 30°C. Developmental data of five constant temperatures, temperature thresholds and thermal requirements may be used to predict the occurrence, number of generations and population dynamics of N. californicus as an important biocontrol agent of Tetranychus urticae.     

Cross-mating experiments with geographically different populations of <Emphasis Type="Italic">Amblyomma cajennense</Emphasis> (Acari: Ixodidae)

The effect of temperature on the development and fecundity of Sancassania polyphyllae fed on tissues of Polyphylla fullo larvae was studied at 15, 20, 25, 30, and 35 ± 1°C and 65 ± 10% RH in a dark incubator. Mean developmental period of immature stages decreased significantly with increasing temperatures from 15 to 30°C. Developmental periods at 30–35°C were not significantly different. The estimated lower developmental thresholds of the various immature stages ranged between 10.1 and 11.5°C. The thermal constant for the egg-to-female adult was 93.5 degree-days. The pre-oviposition, oviposition, and post-oviposition periods and female longevity were significantly longer at 15°C than at higher temperatures. Mean total and daily fecundity were the highest at 25°C, which were significantly different from those obtained at 15, 20 and 30°C. The net reproductive rate (R ₀) was the highest at 25°C (588.3 ♀/♀). The longest mean generation time (T ₀) occurred at 15°C (36 days) and the shortest occurred at 30°C (9.2 days). The highest intrinsic rate of increase (r _m) for S. polyphyllae was observed at 25 (0.61 ♀/♀/day) and 30°C (0.62 ♀/♀/day).     

Effect of temperature on immature development and longevity of two introduced opiine parasitoids on Bactrocera invadens

Temperature‐dependent development, parasitism and longevity of the braconid parasitoids, Fopius arisanus Sonan and Diachasmimorpha longicaudata Ashmed on Bactorcera invadens Drew Tsuruta & White, was evaluated across five constant temperatures (15, 20, 25, 30 and 35°C). Developmental rate decreased linearly with increasing temperature for both the parasitoid species. Linear and Brière‐2 nonlinear models were used to determine the lower temperature threshold at which the developmental rate (1/D) approached zero. For F. arisanus, lower thresholds to complete development estimated with the linear and nonlinear models were 10.1 and 6.9°C, respectively. The total degree‐days (DD) required to complete the development estimated by the linear model for F. arisanus was 360. In D. longicaudata, the linear and nonlinear models estimated lower thresholds of 10.4 and 7.3°C, respectively, and the total DD estimated was 282. In F. arisanus, percentage parasitism differed significantly across all temperatures tested and was highest at 25°C (71.1 ± 2.5) and lowest at 15°C (46.4 ± 1.4). Parasitoid progeny sex ratio was female biased at all temperatures except at 20°C. In D. longicaudata, percentage parasitism was highest at 20°C (52.2 ± 4.0) and lowest at 15°C (27.7 ± 2.5). Parasitoid progeny sex ratio was female biased and similar for all temperatures. Adult longevity of both parasitoids was shortest at 35°C and longest at 15°C, and females lived significantly longer than males at all temperatures tested. Our findings provide some guidance for future mass rearing and field releases of the two parasitoids for the management of B. invadens in Africa.     

Thermal effects on the biological parameters of the predatory mirid Pilophorus gallicus (Hemiptera: Miridae)

Pilophorus gallicus Remane (Hemiptera: Miridae) is a predatory mirid reported in deciduous trees in the western Mediterranean area. This work aimed to determine the biological and demographic parameters for this species at different temperatures (15, 20, 25 and 30°C). Egg hatching times shortened from 57.8 days at 15°C to 9.2 days at 30°C, and nymphal development times declined from 62.8 days at 15°C to 11.1 days at 30°C. The hatching and nymphal survival rates were low at 15 and 30°C. The lower thermal thresholds for the egg and nymphal development were 12.4 and 12.0°C, respectively. These high thermal thresholds could be a safety mechanism to avoid the emergence of nymphs in the unfavorable winter period. Female weight increased between 15 and 25°C and decreased at 30°C. The fecundity increased from 70.2 eggs per female at 15°C to 212.4 eggs per female at 25°C, and decreased to 88.5 eggs per female at 30°C. Fertility ranged from 9.4% at 15°C to 40.9% at 25°C, being 24.9% at 30°C. The intrinsic rate of natural increase (r_m) rose from 0.001 to 0.081 between 15 and 25°C and decreased to 0.05 at 30°C. In summary, this species performs poorly at low temperatures and has a relative tolerance of high temperatures (30°C); its performance was best at 25°C. Knowledge of the variation in the biological parameters with temperature may be very useful for the understanding of its ecology and population dynamics.     

Effect of temperature on the life history and demographic parameters of Spalgis epius (Lepidoptera: Lycaenidae), a candidate biological control agent of mealybugs (Hemiptera: Pseudococcidae)

Many species of mealybugs (Hemiptera: Pseudococcidae) are serious pests of economically important crops worldwide. We evaluated the influence of constant temperatures: 14, 16, 18, 20, 22, 24, 26, 28, 30, 32 and 34°C on the life history and demographic parameters of Spalgis epius (Lepidoptera: Lycaenidae), a candidate biological control agent of various species of mealybugs. No eggs completed their development at 14 and 34°C. Egg-to-adult developmental time significantly decreased from 89.9 days at 16°C to 20.4 days at 32°C. The estimated lower temperature threshold of 10.2°C and 416.6 degree-days were required to complete egg-to-adult development. The mortality of immature stages was maximum at 16 and 32°C and minimum at 28°C. The highest lifetime fecundity was recorded at 28°C and it significantly decreased at 32°C. The longevity of adults was about three times more at 16°C than at 30 and 32°C. The net reproductive rate (R ₀) significantly increased with increased temperatures up to 28°C and significantly decreased at 32°C. The mean generation time (T) significantly decreased with increased temperature up to 30°C, but it significantly increased at 32°C. The intrinsic rate of population increase (r _m ) was highest at 30°C. The finite rate of increase (λ) was significantly greater at 30°C than at other temperatures. These data suggest that S. epius can develop, reproduce and survive in a wide range of temperatures and thus could be regarded a potential biological control agent of mealybugs.     

Time of sowing and temperature effects on the flowering of Stylosanthes guianensis

Seedlings of Stylosanthes guianensis var. guianensis cv. Cook and of two selections of S. guianensis var. pauciflora (CIAT 1280 and CIAT 1062) were grown at day/night temperatures of 20°/25°, 30°/25°, and 35°/30°C in a naturally-lit glasshouse at latitude 27°30'S. Sowings were made in decreasing daylength at 30-day intervals from 22 January to 21 May. Cv. Cook and the CIAT 1280 selection did not flower fully if sown after 22 January and the CIAT 1062 selection did not flower if sown after 22 March. This is interpreted as a long-short day flowering response. Usually, flowers were initiated earlier and at a lower node at 25?/20°C than at the warmer temperatures. At 25?/20°C the first flowers to appear were produced predominantly at the terminal apex of the main stem in cv. Cook and the CIAT 1062 selection, but not in the CIAT 1280 selection. At the two warmer temperatures first flowers were more commonly produced at the terminal apex of primary, secondary and tertiary branches. There were more inflorescences per plant on earlier than later sown plants when measured 21 days from appearance of the first flower and the most inflorescences were produced by cv. Cook at 25?/20°C, by selection CIAT 1062 at 30°/25°C, and by CIAT 1280 at 35°/30°C.     

Life history ofAphis gossypii on cucumber: influence of temperature, host plant and parasitism

Life table data forAphis gossypii Glover (Homoptera: Aphididae), an important pest in glasshouse cucumber crops, were studied at 20, 25 and 30°C on two cucumber cultivars (Cucumis sativus L.) in controlled climate cabinets. The development time on the cucumber cv. ‘Sporu’ ranged from 4.8 days at 20°C to 3.2 days at 30°C. Immature mortality was approximately 20% and did not differ between temperatures. Most mortality occurred during the first instar. Reproduction periods did not differ among temperatures, but at 25 and 30°C more nymphs were produced (65.9 and 69.8 nymphs/♀, respectively) than at 20°C (59,9 nymphs/♀) because of a higher daily reproduction. Intrinsic rate of increase was greatest at 25°C (r _m =0.556 day⁻¹). At 20 and 30°C the intrinsic rate of increase was 0.426 and 0.510, respectively. On cv. ‘Aramon’, the development time ofA. gossypii was approximately 20% longer at all temperatures. Immature mortality did not differ between the two cultivars. The intrinsic rate of increase on cv. ‘Aramon’ was 15% smaller than on cv. ‘Sporu’. The use of cucumber cultivars partially resistant to aphids is discussed in relation to biological control of cotton aphid in glasshouses. Development time and immature mortality on leaves of the middle and upper leaf layer of glasshouse grown cucumber plants (cv. ‘Aramon’) were comparable to development in the controlled climate cabinets. On the lower leaves immature mortality was much higher (approximately 82%) than on leaves of the middle (24.0%) and upper leaf layer (24.5%). Reproduction was less on the lower leaf layer (45.9, 70.5 and 70.1 nymphs/♀ on leaves of the lower, middle and upper leaf layer, respectively). Aphids, successfully parasitized byAphidius colemani Viereck (Hymenoptera: Braconidae) only reproduced when they were parasitized after the third instar. Fecundity was 0.1 to 0.9 and 10.5 to 13.3 nymphs/♀ for aphids parasitized in the fourth instar or as adults, respectively. Reproduction of aphids that were stung but survived the attack was lower than for aphids not stung. Average longevity of these aphids was equal to the longevity of aphids not stung byA. colemani.     

Studies on Prolonged Storage of Beauveria bassiana Conidia: Effects of Temperature and Relative Humidity on Conidial Viability and Virulence against Chickpea Borer,Helicoverpa armigera

Unformulated conidia of Beauveria bassiana were stored at five different temperatures (0°, 10°, 20°, 30° and 40°C) at six different relative humidities (RH) (0, 33, 53, 75, 85 and 98%). Conidial viabilities and virulence against third instar larvae of Helicoverpa armigera were determined over a 24‐month period. Conidia survived longest at lower temperatures (0–20°C) and lower RH levels (0–53% RH). At higher temperatures (30–40°C) conidia did not survive. When the temperature was decreased from 30°C to 0°C, at nearly all RH levels the longevity of conidia increased. Conidia remained virulent for third instar larvae of H. armigera under favourable storage conditions for 24 months.     

INFLUENCE OF TEMPERATURE ON CERTAIN BIOLOGICAL ATTRIBUTES OF A LADYBEETLE COCCINELLA SEPTEMPUNCTATA LINNAEUS

Influence of temperature on certain biological attributes of an aphidophagous ladybeetle, Coccinella septempunctata Linnaeus, feeding on mustard aphid, Lipaphis erysimi (Kaltenbach), at five different temperatures, viz. 20, 25, 27, 30 and 35°C was investigated. Its developmental period was shortest (11.7 ± 0.09 days) at 35°C and longest (20.6 > 0.35 days) at 20°C. Developmental rate increased with increase in temperature. Hatching percent, larval survival, adult emergence and growth index were maximum at 30°C and minimum at 20°C. Oviposition period and fecundity were highest at 30°C and lowest at 20°C. A positive linear relationship exists between temperature and developmental rate and negative correlation between the duration of immature life stages and temperature. The proportion of developmental period allocated to each immature stage was found to be similar at each temperature regime. Thus, 30°C was found as the most suitable for C. septempunctata amongst the five temperatures tested.     

The importance of fluctuating thermal regimes for repairing chill injuries in the tropical beetle Alphitobius diaperinus (Coleoptera: Tenebrionidae) during exposure to low temperature

Abstract. In this study, the impact of acclimation (1 month at 15 °C vs. breeding at 30 °C) and fluctuating thermal regimes (daily transfers from low temperatures to various higher temperatures for 2 h) on the cold tolerance of the tropical beetle, Alphitobius diaperinus Panzer (Coleoptera: Tenebrionidae) was examined. Acclimation increased significantly the duration of survival (Lt₅₀) at a constant 5 °C (7.7 ± 0.3 days to 9.7 ± 0.5 days). Survival of acclimated and nonacclimated beetles increased slightly at alternating temperatures of 5 °C/10 °C or 5 °C/15 °C. When daily transfer to 20 °C was applied, survival (Lt₅₀) was improved markedly (nonacclimated: 15.5 ± 0.7 days, acclimated: 19.6 ± 0.6 days). The higher temperatures may allow progressive repair of injuries, and the effects of chilling may be repaired completely at 25 and 30 °C, a phenomenon recorded here for the first time. It is estimated that the theoretical upper threshold of chill injury (Th) of nonacclimated beetles is 15.1 °C whereas it is shifted down to 11.2 °C in acclimated beetles, which might enable this temperature to allow effective repair of injury.     

Host instar suitability and life-history parameters under different temperature regimes of Necremnus artynes on Tuta absoluta

Necremnus artynes is native to the Mediterranean region where it has been observed in greenhouses parasitising Tuta absoluta on tomato. In this study, we evaluated the suitability of the different instars of T. absoluta as hosts for N. artynes and the life-history traits of N. artynes at three different temperature regimes (20, 25 and 30°C) on third instar T. absoluta larvae infesting tomato. N. artynes females preferred third instar T. absoluta larvae for oviposition, whereas host-feeding was significantly higher on the second instar larvae. Duration of life stages was no different between sexes but was affected by temperature, being significantly reduced as temperature increased. Pre-imaginal survival also decreased with temperature and the percentage of females was ca. 70% under all temperature regimes. Adult longevity was 1.5-fold significantly greater at 25°C compared to 30°C with no differences between 20 and 25°C. Fecundity was estimated at 36.3±7.80, 51.8±10.65 and 52.1±10.03 eggs/female and host-feeding at 59.5±8.50, 71.6±12.07, 51.4±7.89 hosts/female at 20, 25 and 30°C, respectively, although these differences among temperatures were not significant. However, oviposition and feeding rate were significantly higher at 30 and 20°C, respectively. The estimated intrinsic rate of increase (r _m) was significantly higher as temperature increased from 20 to 30°C and it was greater than those reported for T. absoluta on tomato, indicating the potential of N. artynes to control this pest.     

Effects of growth temperature and winter duration on leaf phenology of a spring ephemeral (Gagea lutea) and a summergreen forb (Maianthemum dilatatum)

Effects of growth temperature and winter duration on leaf longevity were compared between a spring ephemeral, Gagea lutea, and a forest summergreen forb, Maianthemum dilatatum. The plants were grown at day/night temperatures of 25/20°C and 15/10°C after a chilling treatment for variable periods at 2°C. The temperature regime of 25/20°C was much higher than the mean air temperatures for both species in their native habitats. Warm temperature of 25/20°C and/or long chilling treatment shortened leaf longevity in G. lutea, but not in M. dilatatum. The response of G. lutea was consistent with that reported for other spring ephemerals. Air temperature increases as the vegetative season progresses. The decrease in leaf longevity in G. lutea under warm temperature condition ensures leaf senescence in summer, an unfavorable season for its growth. This also implies that early leaf senescence could occur in years with early summers. Warm spring temperatures have been shown to accelerate the leafing-out of forest trees. The decrease in leaf longevity due to warm temperature helps synchronize the period of leaf senescence roughly with the time of the forest canopy leaf-out. Prolonged winter due to late snowmelt has been shown to shorten the vegetative period for spring ephemerals. The decrease in leaf longevity due to long chilling treatment would correspond with this shortened vegetative period.     

Influence of temperature and humidity on the survival of Monilinia fructicola conidia on stone fruits and inert surfaces

The survival of the fungus Monilinia fructicola on fruit and inert surfaces at different temperatures (range: 0–30°C) and relative humidity (RH) (range: 60–100%) was investigated. M. fructicola conidia survived better on fruit than on inert surfaces. The viability reduction rate at 20°C and 60% RH was 1.2 and 5.8 days^?1 on fruit and inert surfaces, respectively. Overall, on fruit surfaces, conidia viability was reduced at high temperatures and was longer at higher RH than at lower RH; in contrast, on inert surfaces, conidia viability was longer at only low temperatures. On fruit surfaces, at 0°C and 100% RH, conidia survived up to 35 days, and at 30°C and 60% RH, conidia survived up to 7 days. However, on inert surfaces at 20°C and 30°C, conidia lost their viability after 48 and 24 h, respectively. These results suggest that M. fructicola can remain viable in cold rooms for over 30 days on fruit surfaces or over 25 days on inert surfaces. Furthermore, under the orchard conditions during the growing season, conidia may remain viable for only 2–3 days on immature fruit surfaces before conidia will be unable to penetrate the host.     

Reproduction,survival, and life table parameters of the predatory mite <Emphasis Type="Italic">Cheyletus malaccensis</Emphasis> (Acari: Cheyletidae) at various constant temperatures

Reproduction, survival, and life table parameters of the predatory mite Cheyletus malaccensis Oudemans were evaluated at six constant temperatures: 17.5, 20, 25, 30, 32.5 and 35°C, feeding on Tyrophagus putrescentiae (Schrank). Preoviposition period of fertilized and virgin females varied with temperature from ca. 9 days at 17.5°C to ca. 1.5 day at 32.5°C and then increased to ca. 3 days at 35°C. Virgin female oviposition period was significantly shorter than for fertilized females at the temperatures examined with the exception of 17.5°C. The mean total number of eggs per fertilized (169.7 ± 6.6) and virgin female (60.7 ± 4.3) was highest at the temperature of 30°C. The data indicated a significant positive and nearly doubling effect of fertilization on female fecundity at the temperatures examined with the exception of 17.5°C. Age-specific fecundity was described by a temperature dependent model from which the maximum daily fecundity rate was estimated for fertilized and virgin females at 10.3 (at 30°C) and 6.8 (at 32.5°C) eggs/female, respectively. Virgin female longevity was significantly shorter than for fertilized females at 20, 30 and 32.5°C, and decreased from ca. 57 days at 17.5°C to ca. 17 days at 35°C. The Weibull function that was used to describe the age specific survival of fertilized and virgin females produced excellent fits to the survival data. Estimates of intrinsic rate of increase, net reproductive rate, mean generation time, doubling time and finite rate of increase, were obtained. The r_m value increased with temperature from 0.03 (day⁻¹) at 17.5°C to 0.21 (day⁻¹) at 32.5°C, after which it decreased to 0.15 (day⁻¹) at 35°C. These data indicate that C. malaccensis can reproduce at temperatures between 17.5 and 35°C and can be used for biological control of astigmatid mites within the temperature range where the pest occurs.     

Mortality fecundity and longevity of parasitoids of the spotted tentiform leafminer,Phyllonorycter blancardella [Lep.: Gracillariidae] at constant temperatures in the laboratory

The results of laboratory tests showed that mortality of adult eulophids, primarily,Sympiesis sericeicornis (Nees),S. marylandensis Girault andPnigalio flavipes (Ashmead), was significantly (P<0.05) lower than that of adultPholetesor ornigis (Weed) when exposed to temperatures between 20° and 36°C for 48 h. However, adultP. ornigis lived longer than those of the eulophids at 15°C, but were shorter liver at 33°C. The fecundity ofP. ornigis was little affected at temperatures of 15°, 20°, 24° and 33°C. Exposure of adultP. ornigis to 30°C for 16 h resulted in reduced longevity of both sexes but did not affect fecundity or the proportion of females ovipositing. Mortality of pupae of the eulophids was significantly lower than that of pupae ofP. ornigis at temperatures of 20°, 30° and 33°C. The sex ratio of surviving adults was not affected by temperature.      

Temperature‐dependent development of the double‐spined spruce bark beetle Ips duplicatus (Sahlberg, 1836) (Coleoptera; Curculionidae)

相似文献