Biology and Thermal Requirements of <Emphasis Type="Italic">Fopius arisanus</Emphasis> (Sonan, 1932) (Hymenoptera: Braconidae) Reared on <Emphasis Type="Italic">Ceratitis capitata</Emphasis> Eggs (Wiedemann) (Diptera: Tephritidae)

Fopius arisanus (Sonan) is a solitary parasitoid of eggs and the first instar larvae of Tephritidae. Due to the occurrence of Ceratitis capitata (Wiedemann) in various regions and under several climatic conditions, this study aimed to evaluate the effect of different temperatures on the embryonic development (egg–adult) and determine thermal requirements and the number of annual generations F. arisanus on eggs of C. capitata. In the laboratory, eggs of C. capitata (24 h) were submitted to parasitism of F. arisanus during 6 h. Later, the eggs were placed in plastic containers (50 mL) (50 eggs/container) on a layer of artificial diet and packed in chambers at temperatures 15, 18, 20, 22, 25, 28, 30, and 32 ± 1°C, RH 70 ± 10%, and a photophase of 12 h. The largest number of offspring, emergence rate, and weight of adults of F. arisanus were observed at 25°C. The highest sex ratios (sr > 0.75) were recorded at 15 and 18°C, being statistically higher than the temperatures 20°C (0.65), 22°C (0.64), 25°C (0.65), 28°C (0.49), and 30°C (0.47). At 32°C, there was no embryonic development of F. arisanus. The egg–adult period was inversely proportional to temperature. Based on the development of the biological cycle (egg–adult), the temperature threshold (T _t) was 10.3°C and thermal constant (K) of 488.34 degree-days, being the number of generations/year directly proportional to the temperature increase. The data show the ability of F. arisanus to adapt to different thermal conditions, which is important for biological control programs of C. capitata.     

Effect of Substrate Type and Moisture on Pupation and Emergence of <Emphasis Type="Italic">Heortia vitessoides</Emphasis> (Lepidoptera: Crambidae): Choice and No-Choice Studies

Heortia vitessoides Moore is the most destructive defoliator of Aquilaria sinensis (Loureiro) Sprenger, an endangered and economically important plant that produces the high-prized agarwood. After maturing, H. vitessoides larvae will leave the A. sinensis and pupate in soil, however, factors affecting this behavior have not been previously addressed. In the present study, choice and no-choice tests were conducted to study the effects of substrate type (sand, sandy loam A, sandy loam B, and silt loam) and moisture condition (0 %, 20 %, 40 %, 60 %, 80 %, and 100 % water saturation) on burrowing, pupation and emergence behaviors of H. vitessoides under laboratory conditions. Six-choice tests showed that significantly fewer larvae burrowed and pupated in each substrate under extremely dry (0 % saturation) or wet (80 % and 100 % saturation) conditions. Four-choice tests showed that at 20 % saturation a significantly lower percentage of larvae burrowed and pupated in silt loam as compared to other substrates, whereas at 40 % saturation sand was least preferred. At 60 % saturation, however, there was no significant difference in burrowing and pupation among the four substrates. No-choice test showed that either or both 0 % and 80 % water saturation suppressed burrowing behavior and emergence success compared with the intermediate saturation levels in sandy loam (A and B) and silt loam, but not in sand. In addition, the effect of substrate type varied with saturation level. Our study enhance the understanding of pupation ecology of H. vitessoides, and applied implications are discussed.     

<Emphasis Type="Italic">Talaromyces heiheensis</Emphasis> and <Emphasis Type="Italic">T. mangshanicus</Emphasis>, two new species from China

Two new species, Talaromyces heiheensis from rotten wood and T. mangshanicus isolated from soil, are illustrated and described as new to science in sections Trachyspermi and Talaromyces. The phylogenetic positions of the two new species inferred from the internal transcribed spacer, beta-tubulin, calmodulin and RNA polymerase II second largest subunit regions were carried out. Talaromyces heiheensis is phylogenetically closely related to T. albobiverticillius, T. rubrifaciens, T. solicola and T. erythromellis, and characterised by slow growth on Czapek yeast autolysate agar at 25 °C, orange conidia en masse on malt extract agar at 25 °C, biverticillate and terverticillate conidiophores, acerose phialides and subglobose to ellipsoidal, smooth-walled conidia. Talaromyces mangshanicus is related to T. kendrickii, T. qii and T. thailandensis, and characterised by slow-growing colonies with absent or sparse sporulation on CYA agar at 25 °C, conidia en masse greyish purple, purplish red soluble pigment on yeast extract agar (YES) at 25 °C, biverticillate conidiophores, ampulliform phialides and subglobose to ellipsoidal conidia with echinulate walls. They are distinguished from the known species in culture characteristics on four standard media, microscopic features and sequence data.     

Effects of heat stress on photosynthetic electron transport in a marine cyanobacterium <Emphasis Type="Italic">Arthrospira</Emphasis> sp.

Arthrospira (Spirulina) is widely used as human health food and animal feed. In cultures grown outdoors in open ponds, Arthrospira cells are subjected to various environmental stresses, such as high temperature. A better understanding of the effects of high temperature on photosynthesis may help optimize the productivity of Arthrospira cultures. In this study, the effects of heat stress on photosynthetic rate, chlorophyll a fluorescence transients, and photosystem (PS) II, PSI activities in a marine cyanobacterium Arthrospira sp. were examined. Arthrospira cells grown at 25 °C were treated for 30 min at 25 (control), 30, 34, 37, or 40 °C in the dark. Heat stress (30–37 °C) enhanced net photosynthetic O₂ evolution rate. Heat stress caused over-reduction PSII acceptor side, damage of donor side of PSII, decrease in the energetic connectivity of PSII units, and decrease in the performance of PSII. When the temperature changed from 25 to 37 °C, PSII activity decreased, while PSI activity increased, the enhancement of photosynthetic O₂ evolution was synchronized with the increase in PSI activity. When temperature was further increased to 40 °C, it induced a decrease in photosynthetic O₂ evolution rate and a more severe decrease in PSII activity, but an increase in PSI activity. These results suggest that PSI activity was the decisive factor determining the change of photosynthetic O₂ evolution when Arthrospira was exposed to a temperature from 25 to 37 °C, but then, PSII activity became the decisive factor adjusting the change of photosynthetic O₂ evolution when the temperature was increased to 40 °C.     

Effect of Temperature on Development and Reproduction of <Emphasis Type="Italic">Epilachna dodecastigma</Emphasis> (Wied.) (Coleoptera: Coccinellidae)

The effect of five constant temperatures of 21, 24, 27, 30 and 33 °C on adult life span, reproduction, oviposition behavior and larval developmental time of a bitter gourd inhabited coleopteran insect Epilachna dodecastigma (Wied.) (Coccinellidae) was determined in laboratory conditions under 70 ± 5 % relative humidity and a photoperiod of 12 L : 12 D. Larval developmental time of E. dodecastigma decreased as temperature increased from 21 to 33 °C. Life table data revealed that overall mortality was lowest at 27 °C and highest at 21 °C. Females lived longer than males at all temperatures; but longevity decreased with increase in temperature. Pre-oviposition period decreased significantly with increase in temperature up to 27 °C and thereafter increased at a slower rate; whereas oviposition period decreased significantly with increase in temperature. Fecundity and egg viability increased significantly with an increase in temperature up to 27 °C and thereafter decreased at a slower rate. The intrinsic rate of increase (r _m ) was 0.1703, 0.1984, 0.2235, 0.2227 and 0.2181 day^?1 at 21, 24, 27, 30 and 33 °C, respectively. The net reproductive rate and finite rate of increase was highest at 27 °C (R _o  = 112.05; λ = 1.4233) and lowest at 21 °C (R _o  = 51.23; λ = 1.2581).     

Low temperature and <Emphasis Type="Italic">Daphnia</Emphasis>-associated infochemicals promote colony formation of <Emphasis Type="Italic">Scenedesmus obliquus</Emphasis> and its harvesting

Objective

To explore the combined effects of temperature and Daphnia-associated infochemicals on colony formation of Scenedesmus obliquus to faciliate harvesting the algal biomass.

Results

A three-parameter modified Gaussian model fitted the changes of the number of cells per particle in S. obliquus induced by Daphnia culture filtrate well under any temperature. Decreases in temperature enhanced the induced–colony formation of Scenedesmus. The maximum colony size at 15–25 °C was significantly larger than those at 30–35 °C. An additional 1 or 2 days at low temperature was needed to reach the maximum colony size, which indicates the best harvest time for algal biomass.

Conclusion

Induced-colony formation of Scenedesmus by Daphnia culture filtrate at 15–25 °C is recommended to settle algal cells. This condition facilitates harvesting the biomass.

     

The influence of temperature on life history traits of <Emphasis Type="Italic">Diadegma mollipla</Emphasis> (Hymenoptera: Ichneumonidae), an African parasitoid of the diamondback moth, <Emphasis Type="Italic">Plutella xylostella</Emphasis> (Lepidoptera: Plutellidae)

The use of Diadegma mollipla (Holmgren) as a biocontrol agent for diamondback moth (DBM)—a notorious pest of crucifers—can potentially be improved with increased scientific knowledge of the D. mollipla’s life history. This study investigated the influence of temperature on the life history traits of D. mollipla parasitizing DBM under laboratory conditions with 20 female D. mollipla for each of five constant temperatures i.e., 15, 20, 25, 30 and 35 °C. Data analysis using curvilinear regression models showed that D. mollipla’s highest intrinsic and finite rates of population increase, net reproductive rate, survival of immatures, daily fertility, shortest immature development and doubling times were achieved between 26 and 30 °C. Thus the results of this study provide evidence to that D. mollipla does not thrive well outside the 26–30 °C temperature range. These results provide baseline information for guiding the use of D. mollipla in the biological control of the destructive DBM pest.     

Temperature-induced changes in treatment efficiency and microbial structure of aerobic granules treating landfill leachate

This paper investigates the effect of temperature on nitrogen and carbon removal by aerobic granules from landfill leachate with a high ammonium concentration and low concentration of biodegradable organics. The study was conducted in three stages; firstly the operating temperature of the batch reactor with aerobic granules was maintained at 29 °C, then at 25 °C, and finally at 20 °C. It was found that a gradual decrease in operational temperature allowed the nitrogen-converting community in the granules to acclimate, ensuring efficient nitrification even at ambient temperature (20 °C). Ammonium was fully removed from leachate regardless of the temperature, but higher operational temperatures resulted in higher ammonium removal rates [up to 44.2 mg/(L h) at 29 °C]. Lowering the operational temperature from 29 to 20 °C decreased nitrite accumulation in the GSBR cycle. The highest efficiency of total nitrogen removal was achieved at 25 °C (36.8 ± 10.9 %). The COD removal efficiency did not exceed 50 %. Granules constituted 77, 80 and 83 % of the biomass at 29, 25 and 20 °C, respectively. Ammonium was oxidized by both aerobic and anaerobic ammonium-oxidizing bacteria. Accumulibacter sp., Thauera sp., cultured Tetrasphaera PAO and Azoarcus–Thauera cluster occurred in granules independent of the temperature. Lower temperatures favored the occurrence of denitrifiers of Zooglea lineage (not Z. resiniphila), bacteria related to Comamonadaceae, Curvibacter sp., Azoarcus cluster, Rhodobacter sp., Roseobacter sp. and Acidovorax spp. At lower temperatures, the increased abundance of denitrifiers compensated for the lowered enzymatic activity of the biomass and ensured that nitrogen removal at 20 °C was similar to that at 25 °C and significantly higher than removal at 29 °C.     

High-yield expression,purification, characterization,and structure determination of tag-free <Emphasis Type="Italic">Candida utilis</Emphasis> uricase

We report the successful high-yield expression of Candida utilis uricase in Escherichia coli and the establishment of an efficient three-step protein purification protocol. The purity of the recombinant protein, which was confirmed to be C. utilis uricase by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometer analysis, was >98% and the specific activity was 38.4 IU/mg. Crystals of C. utilis uricase were grown at 18°C using 25% polyethylene glycol 3350 as precipitant. Diffraction by the crystals extends to 1.93 Å resolution, and the crystals belong to the space group P2₁2₁2₁ with unit cell parameters a?=?69.16 Å, b?=?139.31 Å, c?=?256.33 Å, and α?=?β?=?γ?=?90°. The crystal structure of C. utilis uricase shares a high similarity with other reported structures of the homologous uricases from other species in protein database, demonstrating that the three-dimensional structure of the protein defines critically to the catalytic activities.     

Temperature-dependent gastric evacuation rate of the Japanese delicate loach <Emphasis Type="Italic">Niwaella delicata</Emphasis> (Cobitidae)

The gastric evacuation rate (GER) of the delicate loach Niwaella delicata was estimated experimentally under four temperature conditions (10, 15, 20, and 25 °C). The GER was relatively high under the ≥20 °C condition and was nearly zero under the ≤15 °C condition. The relationship between GER and water temperature was estimated following the method of Elliot (1972) as follows: GER = exp (0.436 × temperature ? 10.59). This physical characteristic might affect the seasonal activity of this species.     

Nisin Z produced by <Emphasis Type="Italic">Lactococcus lactis</Emphasis> from bullfrog hatchery is active against <Emphasis Type="Italic">Citrobacter freundii</Emphasis>, a red-leg syndrome related pathogen

Lactococcus lactis subsp. lactis CRL 1584 isolated from a bullfrog hatchery produces a bacteriocin that inhibits both indigenous Citrobacter freundii (a Red-Leg Syndrome related pathogen) and Lactobacillus plantarum, and Listeria monocytogenes as well. Considering that probiotics requires high cell densities and/or bacteriocin concentrations, the effect of the temperature on L. lactis growth and bacteriocin production was evaluated to find the optimal conditions. Thus, the growth rate was maximal at 36 °C, whereas the highest biomass and bacteriocin activity was achieved between 20 and 30 °C and 20–25 °C, respectively. The bacteriocin synthesis was closely growth associated reaching the maximal values at the end of the exponential phase. Since bacteriocins co-production has been evidenced in bacterial genera, a purification of the bacteriocin/s from L. lactis culture supernatants was carried out. The active fraction was purified by cationic-exchange chromatography and then, a RP-HPLC was carried out. The purified sample was a peptide with a 3353.05 Da, a molecular mass that matches nisin Z, which turned out to be the only bacteriocin produced by L. lactis CRL 1584. Nisin Z showed bactericidal effect on C. freundii and L. monocytogenes, which increased in the presence l-lactic acid?+?H₂O₂. This is the first report on nisin Z production by L. lactis from a bullfrog hatchery that resulted active on a Gram-negative pathogen. This peptide has potential probiotic for raniculture and as food biopreservative for bullfrog meat.     

A multi-criteria approach for the selection of efficient biocontrol agents against <Emphasis Type="Italic">Botrytis cinerea</Emphasis> on tomato in Algeria

In order to find biocontrol agents that are both efficient against Botrytis cinerea Pers. and adapted to tomato growing conditions in Algeria, 121 bacterial strains were collected from tomato plants and nearby soils in two Bejaia greenhouses. A total of 37 strains were selected based on their ability to grow on agar medium and on their different level of B. cinerea mycelial growth inhibition in dual-culture tests. These strains were identified at the species level and those that corresponded to potential pathogens for humans or mammals were discarded. Among the remaining 25 candidates, three strains were selected among the Pseudomonas genus for their significant protective efficacy against B. cinerea on tomato, their ability to grow at 15–25 °C and their inability to grow at 37 °C. These three strains significantly reduced the development of necrotic lesion and the sporulation of B. cinerea in a dose-dependent manner. This study constitutes a first step towards the biological control of B. cinerea in tomato greenhouses in Algeria.     

The effect of temperature on growth and lipid and fatty acid composition on marine microalgae used for biodiesel production

Cultivation temperature is one of the major factors affecting the growth and lipid accumulation of microalgae. In this study, the effects of temperature on the growth, lipid content, fatty acid composition and biodiesel properties of the marine microalgae Chaetoceros sp. FIKU035, Tetraselmis suecica FIKU032 and Nannochloropsis sp. FIKU036 were investigated. These species were cultured at different temperatures (25, 30, 35 and 40 °C). The results showed that the specific growth rate, biomass and lipid content of all microalgae decreased with increasing temperature. With regards to fatty acids, the presence of saturated fatty acids (SFAs) in T. suecica FIKU032 and Nannochloropsis sp. FIKU036 decreased with increasing temperature, in contrast with polyunsaturated fatty acids (PUFAs). Moreover, Chaetoceros sp. FIKU035 was the only species that could grow at 40 °C. The highest lipid productivity was observed in Chaetoceros sp. FIKU035 when cultivated at 25 °C (66.73 ± 1.34 mg L^?1 day^?1) and 30 °C (61.35 ± 2.89 mg L^?1 day^?1). Moreover, the biodiesel properties (cetane number, cold filter plugging point, kinematic viscosity and density) of the lipids obtained from this species were in accordance with biodiesel standards. This study indicated that Chaetoceros sp. FIKU035 can be considered as a suitable species for biodiesel production in outdoor cultivation.     

Thermal limits for the establishment and growth of populations of the invasive apple snail <Emphasis Type="Italic">Pomacea canaliculata</Emphasis>

Pomacea canaliculata is a South American freshwater snail considered as one of the world’s worst invasive alien species. A temperature of around 25 °C has usually been considered to be optimal for rearing P. canaliculata. Nevertheless, snails have not been reared under a wide range of temperatures to reveal the optimum for performance in terms of population increase. We investigated the effect of temperature on growth, survival and reproduction, estimating demographic parameters for P. canaliculata in the wide range of temperatures at which these snails are active (15–35 °C). No reproductive activity was evidenced for the snails reared at 15 °C, probably explained by the small sizes attained at this temperature. Temperatures above 25 °C did not promote a significant acceleration in growth so higher temperatures will not result in a reduction in time to reach maturity. In fact, snails from 25 and 30 °C began reproduction at the same age. We report here for the first time a detrimental effect of high temperatures that provoked a significant decrease in the contribution of snails to the next generation: the viability of eggs from the snails reared at 30 °C was very low and the snails exposed to a constant water temperature of 35 °C were unable to produce eggs. Our findings reveal a new environmental constraint that could be a determinant of the range limits of this species in invaded regions, especially during the coming decades, anticipating the scenario predicted from global warming.     

Expression,purification and characterization of a thermostable leucine dehydrogenase from the halophilic thermophile <Emphasis Type="Italic">Laceyella sacchari</Emphasis>

Objective

A potential thermotolerant l-leucine dehydrogenase from Laceyella sacchari (Ls-LeuDH) was over-expressed in E. coli, purified and characterized.

Results

Ls-LeuDH had excellent thermostability with a specific activity of 183 U/mg at pH 10.5 and 25 °C. It retained a high activity in 200 mM carbonate buffer from pH 9.5 to 11. The optimal temperature for Ls-LeuDH was 60 °C.

Conclusion

It is the first time that a thermostable and highly active LeuDH originating from L. sacchari has been characterized. It may be useful for medical and pharmaceutical applications.

     

A method for rearing the yellow-spotted longicorn beetle, <Emphasis Type="Italic">Psacothea hilaris</Emphasis> (Coleoptera: Cerambycidae), to stabilize the last larval instar

The larvae of Psacothea hilaris (Pascoe) grown continuously under a long day in the laboratory pupate after the 4th, 5th, or 6th instar. This developmental polymorphism has complicated studies on the control of metamorphosis in P. hilaris. Since pupation in P. hilaris is known to be suppressed under a short day, a change in the photoperiod from a short to a long day with appropriate timing may assist in obtaining physiologically homogeneous larvae that pupate at the next molt. When the photoperiod was changed from 12-h light:12-h dark to 15-h light:9-h dark at the beginning of the 5th instar, the pupation rate at the next (5th) molt reached 90%, which was significantly higher than the proportion of larvae that pupated after the 5th instar when the larvae were grown continuously under a long day (52%). This rearing technique will expedite studies on the control of metamorphosis in P. hilaris.     

Interspecific variation in extracellular polysaccharide content and colony formation of <Emphasis Type="Italic">Microcystis</Emphasis> spp. cultured under different light intensities and temperatures

Single cells of five different Microcystis species (M. ichthyoblabe, M. viridis, M. flos-aquae, M. wesenbergii, and M. aeruginosa) were batch-cultured at different temperatures and light intensities: (a) 25 °C and 50 μmol photons m^?2 s^?1 (control culture); (b) 25 °C and 10 μmol photons m^?2 s^?1; and (c) 15 °C and 50 μmol photons m^?2 s^?1. The extracellular polysaccharide content was significantly higher in treatments b and c than in the control treatment. All Microcystis species existed as single cells under the control treatment but formed colonies in treatments b and c. All of the colonies were irregular with indistinct margins. M. ichthyoblabe, M. viridis, M. flos-aquae, and M. wesenbergii formed colonies with similar morphologies and their cells were loosely aggregated. In contrast, M. aeruginosa formed denser colonies with no distinct holes. The colony morphologies differed from the classic morphology of M. ichthyoblabe field-grown colonies but resembled that of small colonies found in Lake Taihu (Yangtze Delta Plain, China) during early spring. This indicates that field- and laboratory-grown colonies are governed by similar formation processes. We suggest that in laboratory and field environments, M. ichthyoblabe (or M. flos-aquae) colonies are representative of small colonies formed from single Microcystis cells, whereas the morphology of older colonies evolves to resemble M. wesenbergii and M. aeruginosa colonies.     

<Emphasis Type="Italic">Roseomonas aeriglobus</Emphasis> sp. nov., isolated from an air-conditioning system

A novel pale pink-coloured, strictly aerobic, Gram-stain negative bacterial strain, designated strain KER25-12^T, was isolated from a laboratory air-conditioning system in South Korea. Cells were observed to be non-motile cocci showing positive catalase and oxidase reactions. Strain KER25-12^T was found to grow at 10–30 °C (optimum, 25–30 °C), at pH 4.0–9.0 (optimum, pH 6.0–7.0) and in the presence of 0–2% (w/v) NaCl (optimum, 0%). Ubiquinone-10 and spermidine were detected as the sole respiratory quinone and the predominant polyamine, respectively. The major fatty acids were identified as summed feature 8 (comprising C_18:1 ω7c and/or C_18:1 ω6c), summed feature 3 (comprising C_16:1 ω7c and/or C_16:1 ω6c), C_16:0 and C_18:0. The genomic DNA G+C content of strain KER25-12^T was determined to be 70.0 mol%. The major polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and an unidentified aminolipid. Phylogenetic analysis based on 16S rRNA gene sequence comparison revealed that strain KER25-12^T belongs to the genus Roseomonas and shows high sequence similarity to Roseomonas aerilata 5420S-30^T (98.57%), Roseomonas pecuniae N75^T (97.44%) and Roseomonas vinacea CPCC 100056^T (97.40%). Based on the morphological, physiological, chemotaxonomic and phylogenetic features, strain KER25-12^T is concluded to represent a novel species of the genus Roseomonas, for which the name Roseomonas aeriglobus sp. nov. is proposed. The type strain is KER25-12^T (= KACC 19282^T = JCM 32049^T).     

Hyperthermostable <Emphasis Type="Italic">Thermotoga maritima</Emphasis> xylanase XYN10B shows high activity at high temperatures in the presence of biomass-dissolving hydrophilic ionic liquids

The gene of Thermotoga maritima GH10 xylanase (TmXYN10B) was synthesised to study the extreme limits of this hyperthermostable enzyme at high temperatures in the presence of biomass-dissolving hydrophilic ionic liquids (ILs). TmXYN10B expressed from Pichia pastoris showed maximal activity at 100 °C and retained 92 % of maximal activity at 105 °C in a 30-min assay. Although the temperature optimum of activity was lowered by 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc), TmXYN10B retained partial activity in 15–35 % hydrophilic ILs, even at 75–90 °C. TmXYN10B retained over 80 % of its activity at 90 °C in 15 % [EMIM]OAc and 15–25 % 1-ethyl-3-methylimidazolium dimethylphosphate ([EMIM]DMP) during 22-h reactions. [EMIM]OAc may rigidify the enzyme and lower V _max. However, only minor changes in kinetic parameter K _m showed that competitive inhibition by [EMIM]OAc of TmXYN10B is minimal. In conclusion, when extended enzymatic reactions under extreme conditions are required, TmXYN10B shows extraordinary potential.     

Thermal tolerance of potential <Emphasis Type="Italic">Trichogramma</Emphasis> strains for mass-production and paddy field release in the Greater Mekong Subregion

In order to identify suitable Trichogramma strains for mass production and successful control of key lepidopteran pests in paddy fields in the Greater Mekong Subregion, the effects of high temperatures on wasp life history traits were compared among three strains of Trichogramma chilonis Ishii and two strains of Trichogramma ostriniae Pang et Chen, collected from paddy fields in the region. At a rearing temperature of 25 °C, life history traits differed significantly among the five strains tested and the three T. chilonis strains and a T. ostriniae strain were of high performance. When female wasps were exposed to higher temperatures commonly encountered in the region, negative effects were observed on key life history parameters of adult females and their offspring at 34 °C, which became even more serious at 37 °C. In particular, the two T. ostriniae strains were not able to successfully develop to adulthood at all at 37 °C while for the T. chilonis strains adult emergence was significantly reduced. In addition, the emerged offspring females lived only around one day and no parasitism was observed. When the three T. chilonis strains were exposed to 37 °C for 4 to 12 h at prepupal and pupal stages, reflecting heat shocks that the released Trichogramma may experience in the field, adult emergence was significantly reduced after an exposure time of 12 h. In summary, the three T. chilonis strains show a relatively high potential for incorporation in a biological control program in the target region. Our results also highlight that tests at both rearing and field temperatures are necessary in selection of potential Trichogramma strains for an inundative release program where there is significant difference between rearing and field temperatures.