Bionomics and population growth statistics of apterous virginoparae of woolly apple aphid, Eriosoma lanigerum, at constant temperatures

Development, survival, reproduction and population growth statistics of apterous virginoparae of woolly apple aphid, Eriosoma lanigerum (Hausmann) (Hemiptera: Aphididae) at constant temperatures of 10, 13, 15, 20, 25, 30 and 32°C are reported. The developmental times of all life stages were inversely related to temperature ranging from 10 to 30°C. Span of total development (time from birth to adulthood) decreased from 57.8 days at 10°C to 11.7 days at 30°C and increased to 16.8 days at 32°C. A good linear model fit (R²>0.96) between developmental rate and temperature in the range 10–25°C was observed for all life stages. The lower developmental threshold was estimated at 5.8°C for instar I, 4.8°C for instar II, 4.9° for instar III and 4.4°C for instar IV. The lower temperature threshold for total development was estimated at 5.2°C. The upper developmental limit was found to be 32°C. Mean degree-day accumulations required for completion of instars I, II, III, IV and total development were: 125.6, 51.0, 47.7, 50.7 and 267.6, respectively. Fecundity, larviposition period and adult longevity were reduced with increasing temperature. Net reproductive rate was greatest at 15°C whereas intrinsic rate of increase peaked at 25°C. Optimal performance, as measured by fecundity, survival and intrinsic rate of increase, ocurred in the range 13–25°C.     

中国福建省瘿绵蚜科和大蚜科一新纪录属和三新种（同翅目：蚜总科）

作者在整理福建省蚜虫标本时,发现瘿绵蚜科中国１新纪录属和３新种。模式标本均保存在中国科学院动物研究所昆虫标本馆。     

Effects of temperature and diet on oviposition rate and development time of the New Zealand flower thrips, Thrips obscuratus

The life history of New Zealand flower thrips (Thrips obscuratus (Crawford), Thysanoptera: Thripidae) was studied using a simple laboratory rearing method. The effects of temperature and diet on oviposition rate and development time were examined. Oviposition rate increased with increasing temperature between 10°C and 25°C. Development time for individual instars and for total development decreased with increasing temperature between 10°C and 27°C. Total development time ranged from 50 days at 10°C (female) to 10 days at 27°C (male). The relationship between temperature and development rate was expressed as a straight line such that lower thresholds of development of between 4.2°C and 6.3°C were established for life stages. Adult lifespan increased with decreasing temperature between 10°C and 25°C and females lived longer than males. At 10°C and 25°C females lived for an average of 34 and 3 weeks respectively. Thrips supplied with pollen exhibited highest and sustained levels of egg production in comparison to other diets. Larval mortality was lowest and development time fastest on diets of pollen and sucrose or fruit juice in comparison to other plant tissues. Larval development time was similar on four species of pollen.     

Comparative studies on populations of Pauesia juniperorum (Hymenoptera: Braconidae), a biological control agent for Cinara cupressivora (Hemiptera: Aphididae)

Pauesia juniperorum (Stary), a solitary endoparasitoid which attacks several Cinara spp. in the subgenus Cupressobium, was introduced into Africa for the control of the cypress aphid Cinara cupressivora Watson & Voegtlin (previously identified as Cinara cupressi (Buckton)) and is now established. Data on its biology including a comparison of populations from different hosts and geographical locations are presented. From the UK this consisted of populations reared from Cinara cupressivora, Cinara fresai Blanchard and Cinara juniperi De Geer, and from France, Cinara ?fresai. Between different populations, the duration of development varied within a narrow range (15.5-18.1 days) at 22 degrees C. Data on duration of development over a range of temperatures (15-26 degrees C) for two populations, from the UK and France ranged between 14.0-31.4 days for males and 14.7-32.8 days for females. The threshold temperature for development was 6.2 degrees C and 4.1 degrees C for the populations from the UK and France, respectively. The mean egg load for different populations ranged between 46.4 and 78.5 eggs. The host species had a significant effect on egg load which was directly related to size of the respective host aphids. The lowest egg load was recorded on specimens reared from C. cupressivora which was the smallest aphid. The population from the UK had a higher intrinsic rate of increase (0.232) than the one from France (0.207).     

Development of Apheliuus mali an endoparasitoid of woolly apple aphid, Eriosoma lanigerum at different temperatures

Developmental times for both sexes of Aphelinus mali (Haldeman) (Hymenoptera: Aphelinidae) an endoparasitoid of woolly apple aphid, Eriosoma lanigerum (Hausmann) (Hemiptera: Pemphigidae) were studied at 13, 15, 18, 20, 25 and 30°C and compared with those of E. lanigerum. Mean developmental times ranged from 11.7–53.3 days for males, 11.8–55.4 days for females and 11.8–54.4 days for both sexes combined and were significantly inversely related to temperature. A good linear model fit (r²>0.99) between developmental rate and temperature in the range 13–30°C was observed. Results indicate significant differences between developmental times of males and females at 13, 18, 20, and 25°C but no differences at 15 and 30°C. The notional developmental threshold was 8.3°C for both males and females. Compared with its host, A. mali has a higher lower developmental threshold. An average of 252.8, 256.7 and 254.8 degree-days (DD) above the lower threshold were required by A. mali to complete development from time of oviposition to adult emergence for males, females and both sexes combined, respectively. Field experimentation also indicated that the developmental time of A. mali lags significantly behind that of its aphid host throughout the year. These findings are discussed in relation to its status as a biological control agent for E. lanigerum.     

Influence of constant temperatures on life history parameters of the cotton aphid, Aphis gossypii, infesting cotton

Laboratory clip-cage studies were conducted to quantify the temperature-dependent development, survivorship, and reproduction and to generate life history characteristics and population growth parameters of the cotton aphid, Aphis gossypii Glover, on phenologically standardized greenhouse-grown cottons at 10, 15, 20, 25, 30, and 35 degrees C. The developmental thresholds were estimated to be 6.3, 6.7, 5.9, 5.9, and 6.3 degrees C for first to fourth instars and for total nymphal development, respectively. The maximum rate of development were estimated to occur at 32.2, 30.8, 30.4, 30.0, and 30.2 degrees C for first to fourth instars and for total nymphal development, respectively. Increased temperature resulted in more rapid decline in survivorship, which was particularly sharp at 35 degrees C, dropping from 94 to 17% in 5 d. Number of days elapsed until first deposition of progeny increased progressively and sharply at temperatures 10 (26 d) to 15 (15 d) to 20 degrees C (8 d) and stabilized at 5 d for 25, 30, and 35 degrees C. Average lifetime fecundity of females rose from a low of 9.76 progeny at 10 degrees C to a peak of 58.9 progeny at 30 degrees C and declined sharply to 17.3 at 35 degrees C. Finite rate of population growth was highest at 25 degrees C and lowest at 10 degrees C. Although stage-specific developmental maxima occurred between 30 and 32 degrees C, a nonlinear regression model estimated 28.6 degrees C to be the optimum temperature for overall cotton aphid development, reproduction, and population increase.     

Variation and inheritance of resistance to cypress aphid, Cinara cupressi Buckton in Cupressus lusitanica Miller

Cupressus lusitanica seedlings from open-pollinated seeds of 18 families were inoculated with day-old first instar Cinara cupressi. Aphid survival was used to determine the genetic basis and inheritance of resistance to the insect. There was marked variation in aphid survival both between and within families. An individual-tree narrow-sense heritability of 0.76 ± 0.30 shows strong additive genetic control which could allow effective selection and breeding for resistance. Resistant parents produced resistant progeny while susceptible parents produced susceptible progeny. There were notable exceptions as some susceptible parents produced highly resistant progeny, indicating that they had acquired pollen from resistant neighbours. Recovery of aphid damaged trees is evident implying that care should be taken in selecting for resistance. The strong additive variance and potentially high heritability indicate that one cycle of selection may yield a resistant population, while intraspecific crossing may give better results. Implications of the results in a C. lusitanica breeding programme are discussed.     

Relationships between temperature, development and survival of different life stages of the tomato fruit fly, Neoceratitis cyanescens

The development and survival of female Neoceratitis cyanescens (Bezzi) (Diptera: Tephritidae) from egg to complete ovarian maturation were studied in the laboratory at five different constant temperatures: 15, 20, 25, 30, and 35 °C. The aim of this study was to get information on the influence of temperature on pre-mature stages, as a prerequisite to optimise rearing procedures and to understand temporal and geographical patterns of fruit fly occurrence. The developmental rate of the different life stages increased linearly with increasing temperatures up to 30 °C. The fastest development of pre-mature stages was recorded at 30 °C (22±1 days) and the slowest at 15 °C (98±3 days). The day-degrees requirements (K) to complete total development were 432.6 day-degrees. Lower temperature thresholds were 11.4, 11.9, 10.0, and 11.1 °C for egg, larval, pupal stages and ovarian maturation, respectively. The number of adults obtained from an initial batch of 100 eggs reached a maximum (64) at 25 °C. At 35 °C, no adults emerged. Larval developmental time was significantly shorter in green tomato fruits than in potato tubers at 15, 20, and 25 °C. Mortality rate of larvae was higher in green tomato fruits than in potato tubers at 25 and 30 °C.     

Developmental times and life table statistics of Aulacorthum solani (Hemiptera: Aphididae) at six constant temperatures, with recommendations on the application of temperature-dependent development models

Aulacorthum solani (Kaltenbach) (known as foxglove aphid or glasshouse potato aphid) is a pest of increasing economic importance in several agricultural crops worldwide, including greenhouse vegetables and ornamentals. Developmental rates and age-specific life tables for a North American population of A. solani on pansy (Viola × wittrockiana) (Gams.) were determined at six constant temperatures, and comparisons were made to previous studies of A. solani from differing geographic regions and host crops. On pansy, A. solani developed fastest at 25°C, passing through the four nymphal instars in an average of 6.9 d. The highest intrinsic rates of population increase (0.410 and 0.445) and shortest population doubling times (1.69 and 1.56 d) were recorded at 20 and 25°C, respectively. Average total fecundity remained high from 10 to 20°C (74-68 nymphs/adult); a significant decrease to 39 nymphs/adult occurred at 25°C. For calculating developmental thresholds, we present here a method of adjusting the lower developmental threshold (t(min)) using estimates from nonlinear models to provide an improved estimate of the thermal constant (K, in degree-days). We also call attention to the necessity of using a simulation method to estimate the true upper developmental threshold (t(max)) and optimum developmental temperature (t(opt)) from the Lactin-2 model of temperature-dependent development.     

Temperature influences swimming speed, growth and larval duration in coral reef fish larvae

The effects of temperature on growth, pelagic larval duration (PLD) and maximum swimming speed were compared in the tropical fish marine species Amphiprion melanopus, to determine how temperature change affects these three factors critical to survival in larvae. The effects of rearing temperature (25 and 28 °C) on the length of the larval period and growth were examined in conjunction with the effects of swimming temperature (reared at 25 °C, swum at 25 and 28 °C, reared at 28 °C, swum at 25 and 28 °C) on critical swimming speed (U-crit). Larvae reared at 25 °C had a 25% longer pelagic larval duration (PLD) than larvae reared at 28 °C, 12.3 (±0.3) days compared with 9 (±0.6) days at 25 °C. To offset this effect of reduced developmental rate, growth and U-crit were measured in larvae reared at 28 and 25 °C at the same absolute age (7 days after hatching (dah)) and same developmental age (7 dah at 28 °C cf. 11 dah at 25 °C), corresponding to the day before metamorphosis. Larvae reared at 25 °C were smaller than larvae reared at 28 °C at the same absolute age (7 dah at 25 °C cf. 7 dah at 28 °C), yet larger at similar developmental age (11 dah at 25 °C cf. 7 dah at 28 °C) when weight and standard length were compared. This stage-specific size increase did not result in better performance in larvae at the same developmental age, as there was no difference in U-crit in premetamorphic larvae reared at either temperature (7 dah at 28 °C c.f 11 dah at 25 °C). However, U-crit was considerably slower in 7-day-old larvae reared at 25 °C than larvae of the same absolute age (7 dah) reared at 28 °C. Swimming temperature controls demonstrated that a change in temperature immediately prior to swimming tests did not effect swimming performance for larvae reared at either temperature.A decreased in rearing temperature resulted in longer larval durations, reduced growth rates and slower swimming development in larvae. However, the magnitude of the response of each of these traits varied considerably. As such, larvae reared at the lower temperature were a larger size at metamorphosis but had poorer relative swimming capabilities. This study highlights the importance of measuring a range of ecologically relevant traits in developing larvae to properly characterise their relative condition and performance in response to environmental change.     

Lipid Fatty Acid Composition and Thermophilicity of Cyanobacteria

An analysis of lipid fatty acid composition in several unicellular and filamentous forms of mesophilic and thermophilic cyanobacteria was performed. At 47°C (the temperature of thermophilic cyanobacteria maintenance in the collection), the unicellular thermophilic Synechococcus strains were devoid of polyenoic acids as distinct from the mesophilic forms of this genus at the temperature of 20°C (the temperature of this cyanobacterial maintenance in the collection). In the thermophilic Synechococcus elongatusIPPAS B-267 strain, a decrease in temperature did not result in the occurrence of C18 polyenoic acids, but the quantitative relationship between the saturated and unsaturated fatty acids (S/U ratio) was decreased twofold. In contrast, the culturing of mesophilic strains at 25–32°C resulted in an increase in the S/U ratio due to an increase in the proportion of the 16:0 acid. In the Synechococcus IPPAS B-434 strain, this treatment resulted in a decrease in the relative content of monoenoic, mainly hexadecenoic, acids. The cyanobacterium Gloeobacter violaceus, which lacks thylakoids, and whose photosystems are formed in a cell membrane, contained polyenoic acids. The filamentous thermophilic cyanobacterium Phormidium laminosum, at the maintenance temperature of 47°C, did contain polyenoic acids, but their proportion was considerably lower than that in the filamentous mesophilic forms, such as Tolypothrix sp. and Spirulina platensis. A relative content of hexadecenoic acids in Ph. laminosum was higher than in the mesophilic forms. A possible role of hexadecenoic acids in the processes of adaptation of cyanobacteria to high temperatures is discussed. A relationship between the characteristics of fatty acid composition fixed by evolution and the changes caused by adaptation to a particular environment is considered.     

Influence of climatic and nutritional factors on yeast population dynamics in the phyllosphere of wheat

The role of saprophytic phyllosphere yeasts in removing aphid honeydew and other nutrients from wheat leaves was evaluated in growth cabinet experiments at different temperatures and relative humidities. Population densities of both pink and white yeasts (Sporobolomyces roseus and Cryptococcus laurentii, respectively) increased between 12 and 24°C, if nutrients were supplied. White yeast numbers increased rapidly at a constant vapor pressure deficit (VPD) of 0.10 kPa and alternating VPDs of 0.10 and 0.61 kPa (each 12 hours per day) but decreased at a constant VPD of 0.61 kPa. In growth cabinet experiments with aphids on wheat plants, the amount of aphid honeydew on the leaves was lower when yeast population densities were high. Addition of amino acids to leaves with honeydew had no effect on yeast population density or the rate of honeydew consumption. This indicated that low concentrations of amino acids in aphid honeydew are not a limiting factor for honeydew consumption by the yeasts. The naturally occurring saprophytes efficiently removed fructose, sucrose, and melezitose from the phyllosphere of field-grown wheat plants.     

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.     

Effect of temperature on development, growth and feeding of Coccinella septempunctata and Hippodamia convergens reared on the tobacco aphid, Myzus persicae nicotianae

Preimaginal development, mortality, aphid consumption rate, and size and weight upon reaching the adult stage of the aphidophagous coccinellids Hippodamia convergens Guérin-Méneville and Coccinella septempunctata L. collected from Karditsa, central Greece, were examined at four constant temperatures (14, 17, 20 and 23 °C) and L16:D8. The coccinellids fed on the tobacco aphid, Myzus persicae nicotianae Blackman. Egg, larval and pupal mortality was highest at 14 °C reaching 85.0, 73.8 and 29.4% in H. convergens and 49.3, 75.4 and 58.8% in C. septempunctata, respectively. Total preimaginal development ranged from 57.2 to 70.4 days at 14 °C, and to 16.9 and 22.1 days at 23 °C in H. convergens and C. septempunctata, respectively. Heavier and larger adults of H. convergens were obtained at 17 and 20 ° C. In C. septempunctata temperature did not affect adult weight while the lowest size was observed at 14 and 17 °C. Day-degrees requirements for preimaginal development in H. corvengens were 212.9 above a developmental threshold of 11.0 °C. The corresponding values for C. septempunctata were 281.5 and 10.7 °C. In H. convergens total and daily aphid consumption ranged from 46.8 aphids at 14 °C to 85.0 aphids at 23 °C and from 1.5 aphids at 14 °C to 9.2 aphids at 23 °C, respectively. The corresponding values for C. septempunctata were 112.0 and 2.7 at 14 °C and 157.7 and 12.4 at 23 °C. The results show the high potential of both predators as biological control agents against the tobacco aphid. The knowledge obtained could be essential for their appropriate use and for the improvement of mass rearing systems.     

Interactive effect of diet and temperature on instar numbers in Spodoptera litura,with reference to head capsule width and weight

The effects of diet and temperature on instar numbers and head capsule width in Spodoptera litura F. were compared among individuals reared on an artificial diet, lettuce and perilla leaves at 25 and 30 °C. The number of instars that the insect completed varied as diet and temperature were changed. All the larvae developed through seven instars at 25 °C regardless of diet, but at 30 °C, the number of instars varied depending on the diet. All larvae fed on lettuce leaves had six instars, while larvae fed on the artificial diet passed through seven instars. On perilla, 52% of larval individuals had six instars, and the rest had seven instars. Head capsule width could be used effectively to determine the developmental stage of individual larvae. The frequency distribution of head capsule width showed six or seven distinct peaks, depending on diet and temperature conditions. The relationship between mean head capsule width and weight of larvae was described using an exponential model.     

New cold-adapted lipase from Photobacterium lipolyticum sp. nov. that is closely related to filamentous fungal lipases

A Photobacterium strain, M37, showing lipolytic activity, was previously isolated from an intertidal flat of the Yellow Sea in Korea and identified as Photobacterium lipolyticum sp. nov. In the present study, the corresponding gene was cloned using the shotgun method. The amino acid sequence deduced from the nucleotide sequence (1,023 bp) corresponded to a protein of 340 amino acid residues with a molecular weight of 38,026. No sequence similarity was found with any known bacterial lipases/esterases; instead, the most similar enzymes were several filamentous fungal lipases. Although the similarity was very low (less than 16%), there were many conserved regions over the entire sequence and N-terminal oxyanion hole (RG) region, a signature sequence of filamentous fungal lipases. The novel protein M37 was produced in both a soluble and insoluble form when the Escherichia coli cells harboring the gene were cultured at 18°C. The soluble protein exhibited lipase activity in a pH-stat assay using an olive oil emulsion. The M37 lipase also displayed a maximum activity at 25°C and maintained its activity at a low temperature range (5–25°C) with an activation energy (E _a) of 2.07 kcal/mol. Accordingly, these results indicate that the M37 lipase from P. lipolyticum sp. nov. is a new cold-adapted enzyme.     

Aphid-induced reduction of shoot and root growth in Douglas-fir seedlings

1. The short‐ and long‐term effects of photosynthate removal by sap‐sucking herbivores on plant growth were examined by experimentally manipulating densities of an aphid Cinara pseudotsugae (Wilson) on 2‐year‐old Douglas‐fir seedlings Pseudotsuga menziesii (Mirb.) Franco under greenhouse conditions. An 18‐week test was conducted to determine short‐term effects. Effects of long‐term aphid feeding were examined by exposing seedlings to aphid feeding for two consecutive growing seasons. A third experiment evaluated the extent of recovery during 1 year following a single season of aphid feeding. At least 35 seedlings were used in each test. 2. Volume and dry weight of both shoots and roots decreased significantly with increasing aphid feeding in all three experiments. 3. The most significant and severe aphid effect was reduced root tissue density, suggesting carbohydrate depletion due to translocation from roots to shoots. 4. There was no sign of recovery, of either root or shoot growth, during the year following one season of feeding. 5. The results of this study indicate that short‐term feeding by aphids can affect plant growth and structure for a relatively long time.     

Laboratory studies on the life cycle of Leydigia acanthocercoides Fisher (1854) (Cladocera: Chydoridae)

The biology of Leydigia acanthocercoides has been studied under laboratory conditions with reference to longevity, instar duration, growth, fecundity and embryonic development at a temperature range of 28–30 °C. It has three preadult and thirteen adult instars. Under the given laboratory conditions this species produces 20 eggs during a life span of 23 days. The number of eggs produced is uniformly constant in all adult instars. The growth rate seems to be exponential in the early phase of the life cycle as in other Cladocera. The general pattern of embryonic development of L. acanthocercoides is similar to those of other tropical cladocerans though differences in the duration of total developmental period have been recorded.Part of Ph.D. thesis.     

Temperature influence on life table statistics of the chicken miteDermanyssus gallinae (Acari: Dermanyssidae)

An age-specific life table for the chicken miteDermanyssus gallinae (DeGeer, 1778) was based on various observations carried out at 25°C. The generation time was calculated to be 16.8 days; the intrinsic rate of natural increase was 0.12 per day, and the net reproductive rate was 7.2. A nonlinear function was found satisfactory to describe the developmental rate of the different immature lifestages at temperatures below 40°C. The stage-specific survival of the immature life-stages was generally high between 10 and 37°C, but decreased quickly outside this temperature range. Most of the eggs were laid during the first three weeks of the adult life. The proportion of surviving females rapidly decreases after moulting to the adult stage. At a temperature of 30°C, the highest number of eggs (3 eggs per day) was laid.