Mating duration and egg production of the predaceous mite Neoseiulus californicus (Acari: Phytoseiidae) vary with temperature

Effects of constant temperature on mating duration and total fecundity of Neoseiulus californicus females mated once were investigated at 18 °C, 25 °C, 30 °C, and 35 °C with a photoperiod of 16L:8D. Adult mites grown and maintained at 25 °C mated for 315.3 min on average and produced 46.1 eggs per female. These values varied significantly by temperature: 553.6 and 13.9 (18 °C), 261.2 and 26.6 (30 °C), and 253.6 and 23.9 (35 °C), respectively. Duration of copulation was negatively correlated with temperature. However, total egg production peaked at 25 °C and decreased at lower and higher temperatures. Reduced sperm transfer and/or survival rate of sperm in the female body may account for decreased egg production when temperatures are not optimal.     

Effects of constant and fluctuating incubation temperatures on hatching success and hatchling traits in the diamondback terrapin (Malaclemys terrapin) in the context of the warming climate

As global temperatures continue to rise, so too will the nest temperatures of many species of turtles. Yet for most turtle species, including the estuarine diamondback terrapin (Malaclemys terrapin), there is limited information on embryonic sensitivity to elevated temperature. We incubated eggs of M. terrapin at three, mean temperatures (31, 34, 37 °C) under two thermal exposure regimes (constant or semi-naturally fluctuating temperature) and measured hatching success, developmental rate, and hatchling size. Hatching success was 100% at 31 °C and 67% at 34 °C, respectively; at 37 °C, all eggs failed early in the incubation period. These values were unaffected by exposure regime. The modeled LT₅₀ (temperature that was lethal to 50% of the test population) was 34.0 °C in the constant and 34.2 °C in the fluctuating thermal regime, reflecting a steep decline in survival between 33 and 35 °C. Hatchlings having been incubated at a constant 34 °C hatched sooner than those incubated at 31 °C under either constant or fluctuating temperature. Hatchlings were smaller in straight carapace length (CL) and width after having been incubated at 34 °C compared to 31 °C. Larger (CL) hatchlings resulted from fluctuating temperature conditions relative to constant temperature conditions, regardless of mean temperature. Based upon recent temperatures in natural nests, the M. terrapin population studied here appears to possess resiliency to several degrees of elevated mean nest temperatures, beyond which, embryonic mortality will likely sharply increase. When considered within the mosaic of challenges that Maryland's M. terrapin face as the climate warms, including ongoing habitat losses due to sea level rise and impending thermal impacts on bioenergetics and offspring sex ratios, a future increase in embryonic mortality could be a critical factor for a population already experiencing ecological and physiological challenges due to climate change.     

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.     

Changes of lipid content and fatty acid composition of Schizochytrium limacinum in response to different temperatures and salinities

The growth, lipid content and fatty acid composition of Schizochytrium limacinum OUC88 at different temperatures (16, 23, 30 and 37 °C) and salinities (0, 0.9, 1.8, 2.7 and 3.6%, w/v) were analyzed. The strain grew better and lipid contents were higher at 16–30 °C and salinity at 0.9–3.6% (w/v). The adaptive responses of this microbe to temperature and salinity were mainly to regulate the degree of fatty acid unstauration to maintain the normal membrane lipid physical state. However, at 37 °C and 0 salinity, the growth of the strain was inhibited obviously and the lipid content reduced significantly and, some important changes occurred in fatty acid composition, especially the odd-numbered fatty acids 15:0 and 17:0 which amounts increased greatly. In addition, the ratio of DHA to DPA changed at different temperatures and salinities.     

Impact of fluctuating temperatures on development of the koinobiont endoparasitoid Venturia canescens

The effect of temperature on the biology of Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae) is well understood under constant temperature conditions, but less so under more natural, fluctuating conditions. Herein we studied the influence of fluctuating temperatures on biological parameters of V. canescens. Parasitized fifth-instar larvae of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) were reared individually in incubators at six fluctuating temperature regimes (15–19.5 °C with a mean of 17.6 °C, 17.5–22.5 °C with a mean of 19.8 °C, 20–30 °C with a mean of 22.7 °C, 22.5–27.5 °C with a mean of 25 °C, 25.5-32.5 °C with a mean of 28.3 °C and 28.5–33 °C with a mean of 30 °C) until emergence and death of V. canescens adults. Developmental time from parasitism to adult eclosion, adult longevity and survival were recorded at each fluctuating temperature regime. In principle, developmental time decreased with an increase of the mean temperature of the fluctuating temperature regime. Upper and lower threshold temperatures for total development were estimated at 34.9 and 6.7 °C, respectively. Optimum temperature for development and thermal constant were 28.6 °C and 526.3 degree days, respectively. Adult longevity was also affected by fluctuating temperature, as it was significantly reduced at the highest mean temperature (7.0 days at 30 °C) compared to the lowest one (29.4 days at 17.6 °C). Survival was low at all tested fluctuating temperatures, apart from mean fluctuating temperature of 25 °C (37%). Understanding the thermal biology of V. canescens under more natural conditions is of critical importance in applied contexts. Thus, predictions of biological responses to fluctuating temperatures may be used in population forecasting models which potentially influence decision-making in IPM programs.     

Enzymatic and Non-Enzymatic Esterification of long Polyunsaturated Fatty Acids and Lysophosphatidylcholine in Isooctane

Phosphatidylcholine containing large amounts of long polyunsaturated fatty acid, eicosapentaenoic acid (C20:5) and docosahexaenoic acid (C22:6), was synthesized in isooctane. Immobilized phospholipase A₂ was used as a catalyst. A parallel non-enzymatic esterification reaction was investigated in separate experiments.

The concentrations of lyso-phosphatidylcholine, polyunsaturated fatty acids, water and the enzyme were varied over wide ranges as were the temperature and the reaction time. The type of enzyme, carrier and immobilization procedure were held constant.

The yield of phosphatidylcholine was relatively high (about 21%) when the concentration of polyunsaturated fatty acids was high (300 mg/g of reaction mixture) and the water content was low (below 30% of the dry immobilized enzyme). The highest yield of phosphatidylcholine was found at 80 hours and 75°C. However, at this temperature an extensive non-enzymatic reaction between polyunsaturated fatty acids and lyso-phosphatidylcholine occurred. At 80°C the polyunsaturated fatty acids were partly oxidized. Therefore, a temperature of 45°C to 65°C is probably the optimum temperature for the reaction.     

Temperature at immature and adult stages differentially affects mating duration and egg production of Neoseiulus californicus females mated once (Acari: Phytoseiidae)

A series of experiments was conducted to investigate whether temperatures of 18 °C, 25 °C, 30 °C, and 35 °C and a photoperiod of 16L:8D at immature and adult stages would differentially affect the mating duration and egg production of Neoseiulus californicus females mated once. Mating duration was strictly determined by ambient temperature at the time of mating, regardless of the temperatures under which they were raised. Compared with a consistent 25 °C condition, total fecundity of females decreased when temperature conditions of 18 °C, 30 °C, and 35 °C were applied during any life stage (immature, mating, and oviposition periods) or a combination of different stages. In general, however, if mites were raised in conditions of ≤ 25 °C, and mated and oviposited at conditions of ≥ 25 °C, total egg production was relatively high. Based on these results, the adaptation of mites to thermal environments was discussed.     

Effect of temperature on fatty acid composition and development of unfed Siberian sturgeon (A. baerii) larvae

The fatty acid metabolism in fish is influenced by various factors, including fish species, water temperature, water environment and diet supply. The aim of present work is to investigate the fatty acid composition of yolk‐stage Siberian sturgeon larvae reared at three different temperatures. Fertilized Siberian sturgeon eggs were transferred to the Lodi Aquaculture Research Center of the University of Milan, divided in three aquaria, each containing three incubators and incubated at 16°C. After hatching the temperature was switched to 16, 19 and 22°C. Larvae sampling was performed at the end of yolk sac reabsorption. No feed was dispensed during the trial. Eggs and larvae were weighed and fatty acid profile was determined by GC‐FID analysis after lipid extraction by chloroform/methanol mixture and fatty acid transesterification by methanolic hydrogen chloride. The fertilized eggs had a weight of 23.27 mg and a lipid content of 2.67 mg/egg. At hatching, the weight was 12.2 (0.17 SD) mg and lipid content 1.9 (0.6 SD) mg/larva. At the end of the trial, larvae mean weight was 33.6 (3.6 SD), 34.7 (1.8 SD) and 36.9 (1.1 SD) mg, while lipid content was 2.0 (0.3 SD), 2.1 (0.3 SD) and 2.0 (0.2 SD) mg for larvae reared at 16, 19 and 22°C respectively, without statistically significant difference. Larvae subjected to the highest water temperature showed a faster yolk‐sac absorption. No differences were found across temperatures regarding survival rates and regarding ontogenic development. The fatty acid composition of larvae was affected by the temperature. Larvae reared at 16°C had the lowest amount of saturated fatty acids, mainly due to a lower palmitic acid content, that was offset by a higher level of linolenic and linoleic acid, if compared with larvae reared at 19°C and 22°C. The study suggests that at a lower temperature sturgeon spare unsaturated fatty acid consuming preferably saturated fatty acids, increasing our knowledge of the fatty acid metabolism in this species.     

Effects of temperature and growth phase on lipid and biochemical composition of Isochrysis galbana TK1

The lipid and biochemical composition of the haptophyte Isochrysis galbana TK1 was examined. Cultures were grown at 15 °C and 30 °C, and harvested in the exponential and early stationary growth phases. Carbohydrate and protein content varied at the two culture temperatures and growth phases. The highest protein content was found at the exponential growth phase at 15 °C, and the highest carbohydrate content was found at the stationary phase at the same culture temperature. Lipid accumulated in the stationary growth phase and its content was higher at 30 °C than at 15 °C regardless of the growth phase. The neutral lipids were the major class of lipid found in all the cultures. The stationary phase culture had a higher proportion of neutral lipids than the exponential phase culture and the proportion decreased slightly when culture temperature was increased from 15 °C to 30 °C. Phospholipid levels remained constant at the two temperatures, but slightly decreased in the stationary phase. Glycolipids in the exponentially growing cells were higher than those from stationary growth phase and increased with temperature. Polyunsaturated fatty acids (PUFAs) predominated in glycolipids and phospholipids. Cells grown at 15 °C contained higher proportion of 18:3 (n–3) and 22:6 (n–3) with a corresponding decrease in 18:2 (n–6), monounsaturated and saturated fatty acids. This revised version was published online in August 2006 with corrections to the Cover Date.     

EFFECTS OF LOWERING TEMPERATURE DURING CULTURE ON THE PRODUCTION OF POLYUNSATURATED FATTY ACIDS IN THE MARINE DIATOM PHAEODACTYLUM TRICORNUTUM (BACILLARIOPHYCEAE)1

The composition of fatty acids and contents of eicosapentaenoic acid (EPA) and polyunsaturated fatty acids (PUFAs) of the economically important marine diatom, Phaeodactylum tricornutum (Bohlin), were investigated to see whether reducing the culture temperature enhances the production of EPA and PUFAs. The contents of EPA and PUFAs of P. tricornutum were found to be higher at lower temperature when cultured at 10, 15, 20, or 25°C. When the cells grown at 25°C were shifted to 20, 15, or 10°C, the contents per dry mass of PUFAs and EPA increased to the maximal values in 48, 24, and 12 h, respectively. The highest yields of PUFAs and EPA per unit dry mass (per unit volume of culture) were 4.9% and 2.6% (12.4 and 6.6 mg·L^?1), respectively, when temperature was shifted from 25 to 10°C for 12 h, both being raised by 120% compared with the control. The representative fatty acids in the total fatty acids, when temperature was lowered from 25 to 10°C, decreased proportionally by about 30% in C_16:0 and 20% in C_16:1(n?7) but increased about 85% in EPA. It was concluded that lowering culture temperature of P. tricornutum could significantly raise the yields of EPA and PUFAs.     

Temperature affects the limitation of Daphnia magna by eicosapentaenoic acid,and the fatty acid composition of body tissue and eggs

1. Poikilothermic animals incorporate more polyunsaturated fatty acids (PUFAs) into their cellular membranes as temperature declines, suggesting an increased sensitivity to PUFA limitation in cool conditions. To test this we raised Daphnia magna at different temperatures and investigated the effect of varying dietary PUFA on life history parameters (i.e. growth, reproduction) and the PUFA composition of body tissue and eggs. 2. Upon a PUFA‐rich diet (Cryptomonas sp.) females showed higher concentrations of several ω3 PUFAs in their body tissue at 15 °C than at 20 °C and 25 °C, indicating a greater structural requirement for ω3 PUFAs at low temperature. Their eggs had an equal but higher concentration of ω3 PUFAs than their body tissue. 3. In a life history experiment at 15 and 20 °C we supplemented a diet of a PUFA‐free cyanobacterium with the ω3 PUFA eicosapentaenoic acid (EPA). The growth of D. magna was more strongly EPA limited at low temperature. A greater requirement for structural EPA at 15 °C was indicated by a steeper increase in somatic EPA content with dietary EPA compared to 20 °C. 4. At 20 °C the development of eggs to successful hatching was high when EPA was supplied to the mothers. At 15 °C the hatching success was generally poor, despite of a higher maternal provision of EPA to eggs, compared to that at 20 °C, suggesting that EPA alone was insufficient for proper neonatal development at the low temperature. The growth of offspring from mothers raised at 20 °C without EPA supplementation was very low, indicating that the negative effects of EPA deficiency can be carried on to the next generation. 5. The fatty acid composition of Daphnia sp. in published field studies shows increasing proportions of saturated fatty acids with increasing environmental temperature, whereas ω3 PUFAs and EPA show no clear pattern, suggesting that variations in dietary PUFA may mask temperature‐dependent adjustments in ω3 PUFA concentrations of cladocerans in nature.     

Effect of temperature on survival and immature development of Arma chinensis

Arma chinensis (Fallou) is a predaceous pentatomid with the potential to control a wide range of insect pests. In this study, the stage-specific temperature-dependent development and survival of A. chinensis was investigated under seven constant temperatures (range 18–35 °C) when fed with yellow mealworm (Tenebrio molitor L.). Developmental times (in days) for the immature stage, entire nymphal stage, and egg-to-adult development were inversely proportional to temperatures between 18 and 33 °C (30 °C for eggs and 1st instar nymphs). The lowest survival rate of A. chinensis was observed at 18 °C (6.7%), whereas it was the highest (80–93.3%) at temperatures ranging from 21 to 24 °C. The low temperature thresholds for the egg, entire nymph stage, and egg-to-adult development were 14.3, 12.28, and 12.8 °C, respectively, while the thermal constants for these stages were estimated to be 85.47, 334.9, and 423.8° days. Among the three non-linear models examined, the Taylor model showed the best fit for the egg data, the Briére1 model was the best fit for the 1st instar nymph stage, and the Lactin1 model was more approprate for all the other instar stages, the entire nymphal stage, and overall development. The upper temperature thresholds estimated using the Lactin1 model for eggs, overall nymphal stage, and egg-to-adult development were 38.57, 38.9, and 40.0 °C. The optimal temperature for the overall egg-to-adult period was estimated to be 33.5 °C. The results of this study can be used for the mass rearing of this natural pest enemy and development of phenology models of its seasonal progress.     

Incubation temperature affects hatching success,embryonic expenditure of energy and hatchling phenotypes of a prolonged egg-retaining snake,Deinagkistrodon acutus (Viperidae)

We used eggs of Deinagkistrodon acutus to study the effects of incubation temperature on hatching success, embryonic expenditure of energy and hatchling phenotypes. One egg from each of the 15 fertile clutches was dissected for determination of egg composition, and a total of 164 eggs were incubated at five constant temperatures. Embryonic mortality increased dramatically at 30 °C, and none of eggs incubated at 32 °C hatched. Within the range from 24 to 30 °C, temperature affected incubation length and most hatchling traits examined. The mean incubation length at 24, 26, 28 and 30 °C was 36.4, 28.7, 21.8 and 15.7 days, respectively. Embryos developing at higher temperatures (28 and 30 °C) consumed more energy but produced less developed (and hence smaller) hatchlings, which characteristically had larger residual yolks but smaller carcasses. A principal component analysis resolved two components (with eigenvalues ⩾1) from ten size (initial egg mass)-free hatchling variables, accounting for 79.3% of variation in the original data. The first component (43.8% variance explained) had high positive loading for size-free values of dry mass, lipid mass, energy contents and ash mass of hatchlings, and the second component (35.5% variance explained) had high positive loading for size-free values of SVL, carcass dry mass and fatbody dry mass. Hatchlings from different incubation temperatures did not differ in scores on the first axis of the principal component analysis, whereas hatchlings from higher incubation temperatures (28 and 30 °C) had significantly lower scores on the second axis than did those from lower incubation temperatures (24 and 26 °C). As the second axis mainly represents traits relating to the developmental condition at hatching, the analysis therefore provided further evidence that eggs incubated at higher temperatures produced less developed hatchlings. Taken together, our data show that the optimal temperatures for embryonic development are relatively low in D. acutus largely due to its use of relatively cool habitats.     

Does temperature modify slow and fast development in two aphidophagous ladybirds?

Development within a population is known to vary with abiotic and biotic factors. However, instances of slow and fast development, i.e. different development rates within the same egg batch or cohort, have not yet been rigorously investigated in many organisms. The present study was undertaken to assess the influence of an exogenous cue, temperature (15, 20, 25, 30 and 35 °C), on slow and fast development and its effect on reproductive attributes in two ladybird species, Menochilus sexmaculatus (Fabricius) and Propylea dissecta (Mulsant) (Coleoptera: Coccinellidae). A clear bimodal pattern of distribution with two peaks was found at each temperature where the first peak represented the fast developers and the second peak slow developers. Variation in ratio and development of slow and fast developers within a cohort at different temperatures was observed to ascertain whether the phenomenon has a purely genetic basis or is environmentally influenced. The ratio of slow and fast developers in a cohort differed with temperature but not with species. Slow developers showed a female biased sex ratio and low body mass. Fast developing females laid higher numbers of eggs with higher egg viability than slow developing ones. More slow developers were found at low temperature (15 and 20 °C), equal numbers at medium temperature (25 °C) and less at higher temperature (30 and 35 °C). Results of the study are indicative of stability of the slow and fast development in the egg batch and the likelihood that the variation observed at emergence was owing to exogenous cues influenced differential rates of mortality.     

Does overwinter temperature affect maternal body composition and egg traits in yellow perch Perca flavescens?

Female yellow perch Perca flavescens exposed to three overwinter temperature regimes (4, 8 and 13° C) for 150 days spawned in markedly different proportions upon spring warming (37% of females in 4° C v. 64 and 91% in 8 and 13° C treatments, respectively), but exhibited no differences in fecundity, egg size or egg lipid content. Females held at 4° C also exhibited less within‐clutch egg size variation than females held at 13° C. Moreover, eggs differed among temperature treatments in the overall proportions of 18 fatty acids, with the colder treatments resulting in potentially higher quality eggs containing more of the unsaturated fatty acids C16:1, C22:6‐n3 and C18:2 cis. Female somatic condition also varied with temperature. Maternal somatic growth and protein content increased while lipid content decreased in 13° C compared to the colder treatments. There were, however, no differences among treatments in the fatty acid composition of maternal muscle. These results suggest that the temperatures experienced during winter may be less influential to P. flavescens egg size or number, which may exhibit relatively little plasticity in this species, but can alter both the number of females that spawn and the overall composition of eggs and maternal somatic tissues, which may have implications for future reproductive success.     

Studies of the effect of environmental factors on the rotifer predator–prey system in freshwater

The aim of this work is to evaluate the effect of environmental factors: temperature and photoperiod on the zooplankton predator–prey system. Rotifers, an important and cosmopolitan group of zooplankton in freshwater, were used in our study. We investigated the effect of temperature (20, 23, and 30°C) and of photoperiod (L:D = 12:0 and 0:12) on the predatory rotifer Asplanchna brightwelli consuming rotifer Brachionus calyciflorus as prey. Under A. brightwelli predation, populations of B. calyciflorus prey were consumed more slowly at 20 ± 1 and 30 ± 1°C as compared to 23 ± 1°C. Prey consumption by A. brightwelli increased from 0.63 ± 0.09 ind. predator⁻¹ at 20°C to a peak of 1.22 ± 0.12 ind. predator⁻¹ at 23°C, then decreased significantly to 0.93 ± 0.14 ind. predator⁻¹ at 30 ± 1°C. In addition, predation responded to temperature changing sensitively and rapidly. Statistical analysis showed that the prey consumption were significant different under altered temperature periods during 12 h. Photoperiod also significantly influenced the rate of A. brighwelli predation. B. calyciflorus suffered less predation in darkness than in light. The rate of prey consumption in light (1.06 ind. predator⁻¹) was twice the average of that in darkness (0.51 ind. predator⁻¹). Furthermore, predation rate varied under changing photoperiod but predators moved back into the light did not resume their original consumption rate. Our results demonstrate that whether the predation in rotifer successfully or not is strongly influenced by temperature and photoperiod.     

Effects of different temperatures on the life history of Evania appendigaster L. (Hymenoptera: Evaniidae), a solitary oothecal parasitoid of Periplaneta americana L. (Dictyoptera: Blattidae)

The influence of temperatures on the life parameters of the solitary oothecal parasitoid Evania appendigaster, was investigated in the laboratory. Parasitized oothecae of Periplaneta americana were left to develop under seven constant temperatures: 15, 17, 20, 25, 30, 35, and 40 °C. At the end, we found that: (i) E. appendigaster was able to complete development within the temperature range of 17–34 °C; (ii) mean adult longevity decreased as temperature increased, with the temperature of 40 °C being fatal in a matter of hours; (iii) males lived longer than females between 15 and 30 °C; (iv) adult emergence rate was the highest at 25 °C, and (v) no wasps emerged at 15 or 40 °C. Non-emerged oothecae contained either unhatched eggs or dead larvae. We determined the theoretical lower developmental threshold and thermal constant for the complete development as 12.9 °C and 584.8 day-degrees for males, and 13.1 °C and 588.2 day-degrees for females, respectively. A good balance between faster development, maximum adult longevity and good egg viability was obtained between 25–30 °C, and that would be the best temperature range for rearing E. appendigaster.     

Effects of high night temperature on lipid and protein compositions in tonoplasts isolated from Ananas comosus and Kalanchoë pinnata leaves

Effects of high night temperature on the lipid and protein compositions in the tonoplasts isolated from the leaves of two Crassulacean acid metabolism (CAM) plants, Ananas comosus (pineapple) and Kalanchoë pinnata were studied. The results showed that the phospholipids/protein ratios in the tonoplasts isolated from pineapple and K. pinnata leaves decreased from 1.82 to 1.21 and 2.63 to 1.50, respectively, as the night temperature increased from 20 to 37 °C. Under high night temperature, relative amount of total unsaturated fatty acids in K. pinnata was increased by 6 %, which was mainly caused by increased C18:2 and C18:3, whereas unsaturated fatty acids, C18:2 and C18:3 in pineapple did not show significant change. The distribution patterns of tonoplast proteins in the two CAM species were different between normal and high night temperature and in K. pinnata, especially those with molecular mass ranging from 66.2 to 97.4 KDa. Compared with normal night temperature, more proteins were found in pineapple, but no difference was found in K. pinnata. Thus, above result indicated that the pineapple tonoplasts could keep higher rigidity under high night temperatures compared to the K. pinnata.     

Incubation temperature fluctuation does not affect incubation length and hatchling phenotype in the Chinese skink Plestiodon chinensis

Studies examining the effects of incubation temperature fluctuation on the phenotype of hatchling reptiles have shown species variation. To examine whether incubation temperature fluctuation has a key role in influencing the phenotype of hatchling Chinese skinks (Plestiodon chinensis), we incubated eggs produced by 20 females under five thermal regimes (treatments). Eggs in three treatments were incubated in three incubators, one set constant at 27 °C and two ramp-programmed at 27±3 °C and 27±5 °C on a cycle of 12 h (+) and 12 h (−). The remaining eggs were incubated in two chambers: one inside a room where temperatures varied from 23.0 to 31.1 °C, with a mean of 27.0 °C; the other outside the room where temperatures varied from 20.2 to 35.3 °C, with a mean of 26.1 °C. We found that: (1) for eggs at a given embryonic stage at ovipositon, the mean rather than the variance of incubation temperatures determined the length of incubation; (2) most (egg mass, embryonic stage at oviposition, incubation length and all examined hatchling traits except tail length and locomotor performance) of the examined variables were affected by clutch; and (3) body mass was the only hatchling trait that differed among the five treatments, but the differences were tiny. These findings suggest that incubation temperature fluctuation has no direct role in influencing incubation length and hatchling phenotype in P. chinensis.     

Variation of specific proteins, mitochondria and fatty acid composition in gill of Scylla serrata (Crustacea, Decapoda) under low temperature adaptation

The mud crab Scylla serrata is an important commercial crustacean inhabiting estuarine water along the coast of southeast China. Metabolism in the gill is affected continuously by fluctuating water temperature and, therefore, the ability to cope with temperature change is essential to maintain physiological function. This experiment was conducted to help understand the mechanism of low temperature adaptation in S. serrata gill. In this study, 40 healthy juvenile male S. serrata from the same broodstock were grouped randomly into four groups, which were kept at 5 °C, 10 °C, 15 °C and 27 °C, with the same feeding regime during a 3-week adaptation period. Two-dimensional electrophoresis of the proteome was conducted to separate the specific proteins responsible for low temperature adaptation. Variations in the mitochondria were observed using transmission electron microscopy, and fatty acid composition was determined using gas chromatography. The results showed that different numbers of specific proteins were expressed under different low temperature adaptation, with more expressed at 5 °C and 10 °C than at 15 °C. Mitochondrial morphology also varied under different low temperature adaptation, but there was no linear relationship between microbial density and adaptation temperature. The composition of different fatty acids in the gill varied considerably with adaptation temperature, but elongation of the carbon chain and transition from fatty acids occurred at lower temperatures. Thus, changes in the specific proteins, mitochondria and fatty acid composition of the gill were the positive effects of low temperature on metabolism, leading to improved adaptation ability in S. serrata.