Effect of temperature on the morphometric development of eggs in the prawn Macrobrachium americanum (Caridea: Palaemonidae) and larval success under experimental conditions

Abstract

This study evaluated the effect of temperature on morphometric features of the egg during the embryonic development of the prawn Macrobrachium americanum and the relationship with hatching and the survival of the larvae. Berried females were grouped (n = 3) and reared at three different temperatures, 26, 29, and 33 °C, for which seven developmental stages were recognized. At each stage, the apical and sagittal diameters of the eggs were measured, the volume was calculated, and the weights were recorded. Additionally, the duration of embryonic development, hatching percentage, and larval survival were determined. At 29 and 33 °C, the eggs’ volume increased by 50%, but at 26 °C, the increase was 25%. Larvae from eggs incubated at 33 °C died one day after hatching. At 29 °C, larvae survived until Zoea VII. Larvae from eggs incubated at 26 °C died at the end of Zoea I. The number of days of embryonic development was 20.5 ± 1.5 (26 °C), 15 ± 1 (29 °C), and 12 ± 1 (33 °C). A temperature of 29 °C was the most favorable for embryonic development in M. americanum.     

Geological cycles

Abstract

Deep body temperature (DBT) and heart rate (HR) circadian rhythms were determined by radiotelemetry in 4 mares kept under controlled light and temperature conditions. Ovulations were determined by rectal palpation of their ovaries. Mean DBT values ranged from 35.85 ± .04 to 37.22 ± .02°C The circadian range of oscillation was extremely low, approximately 0.5° C, with time of maximum temperature occurring midway through the dark period. Mean HR values ranged from 36.4 ± 1.7 to 53.0 ±3.6 beats per min. The circadian range of oscillation was also low, less than 15 beats per min with time of maximum HR occurring approximately at the time of lights off. The HR circacadian rhythm peaked before the DBT circadian rhythm by 3 to 8 hrs. Ovulation did not appear to consistently affect DBT and HR circadian rhythms or their phase relationships.     

The daily,weekly, and seasonal cycles of body temperature analyzed at large scale

ABSTRACT

We performed large-scale analyses of circadian and infradian cycles of human body temperature, focusing on changes over the day, week, and year. Temperatures (n= 93,225) were collected using temporal artery thermometers from a Boston emergency department during 2009–2012 and were statistically analyzed using regression with cyclic splines. The overall mean body temperature was 36.7°C (98.1°F), with a 95% confidence interval of 36.7–36.7°C (98.1–98.1°F) and a standard deviation of 0.6°C (1.1°F). Over the day, mean body temperature followed a steady cycle, reaching its minimum at 6:00–8:00 and its maximum at 18:00–20:00. Across days of the week, this diurnal cycle was essentially unchanged, even though activities and sleeping hours change substantially during the weekly cycles of human behavior. Over the year, body temperatures were slightly colder in winter than summer (~0.2°C difference), consistent with most prior studies. We propose these seasonal differences might be due to ambient effects on body temperature that are not eliminated because they fall within the tolerance range of the thermoregulatory system. Over the year, bathyphase (daily time of minimum temperature) appeared to parallel sunrise times, as expected from sunrise’s zeitgeber role in circadian rhythms. However, orthophase (daily time of maximum temperature) and sunset times followed opposite seasonal patterns, with orthophase preceding nightfall in summer and following nightfall in winter. Throughout the year, bathyphase and orthophase remained separated by approximately 12 h, suggesting this interval might be conserved. Finally, although 37.0°C (98.6°F) is widely recognized as the mean or normal human body temperature, analysis showed mean temperature was <37.0°C during all times of day, days of the week, and seasons of the year, supporting prior arguments that the 37.0°C standard has no scientific basis. Overall, this large study showed robust and consistent behavior of the human circadian cycle at the population level, providing a strong example of circadian homeostasis.     

Life tables of the predatory mite Neoseiulus cucumeris (Acari: Phytoseiidae) on two pest mites as prey,Aculops lycopersici and Tetranychus urticae

Abstract

Studies on the life history and life table parameters of Neoseiulus cucumeris Oudemans (Acari: Phytoseiidae) were carried out under laboratory conditions of 25?±?1?°C and 65?±?5% RH; 30?±?1?°C and 60?±?5% RH; 35?±?1?°C and 55?±?5% RH. As prey, immature stages of tetranychid spider mite T. urticae Koch (Acari: Tetranychidae) and the moving stages of the Tomato Russet Mite A. lycopersici (Massee) (Acari: Eriophyideae) were selected. The predatory phytoseiid mite, Neoseiulus cucumeris (Oudemans) was able to develop successfully from egg to adult stage through the entire life history on both preys. The higher of different temperatures and relative humidities shortened the development and increased reproduction and prey consumption and vice versa. The maximum reproduction (3.91, and 3.09 eggs/♀/day) was recorded at 35?°C and 65% RH, while the minimum (2.12, and 1.90 eggs/♀/day) was at 25?±?1?°C and 55?±?5% RH. when N. cucumeris fed on A. lycopersici and T. urticae, respectively. The reproductive rate on eriophyid was significantly higher than previously recorded on tetranychid. Life table parameters indicated that feeding of phytoseiid mite N. cucumeris on tomato russet mite A. lycopersici led to the highest reproduction rate (rm?=?0.268, 0.232 and 0.211 females/female/day), while feeding on T.urticae gave the lowest reproduction rate (rm?=?0.159, 0.143 and 0.131) at 35?°C and 55% RH, 30?°C and 60% RH and 25?°C and 65% RH, respectively. The population of N. cucumeris multiplied (36.81, 28.71 and 20.47) and (24.60, 19.58 and 14.62 times) in a generation time of (20.10, 23.20 and 25.14) and (22.35, 25.36 and 27.79 days) when a predator fed on A. lycopersici and T. urticae at the same temperature above mentioned, respectively. These results suggest that the two mites, particularly A. lycopersici, proved to be suitable prey for N.cucumeris, as a facultative predator.     

Thermal responses of an insect subjected to temperature variations

Temperature responses of the cockroach, Blaberus craniifer, to rapid changes of ambient temperature (T_a) have been studied. In static conditions at T_a = 27°C the body-to-ambient temperature difference was only 0.10 ± 0.07°C. Two test situations were used, either a ramp increase of T_a from 27 to 31°C (0.1°C/min) or “step” changes from 27 to 28°C and back (0.5°C/min). In both cases body temperature closely followed Newtonian model, the body time constants measured in various conditions being very similar: 543 ± 99 sec in ramp tests, 550 ± 68 sec and 542 ± 124 sec in rising and falling step tests respectively. It is concluded that in spite of evident differences between the cockroach and an inert solid, the Newtonian model adequately represents the thermal responses of this insect to moderate changes in ambient temperature.     

Thermoregulation in premature infants: A mathematical model

PurposeIn 2010, approximately 14.9 million babies (11.1%) were born preterm. Because preterm infants suffer from an immature thermoregulatory system they have difficulty maintaining their core body temperature at a constant level. Therefore, it is essential to maintain their temperature at, ideally, around 37 °C. For this, mathematical models can provide detailed insight into heat transfer processes and body-environment interactions for clinical applications.MethodsA new multi-node mathematical model of the thermoregulatory system of newborn infants is presented. It comprises seven compartments, one spherical and six cylindrical, which represent the head, thorax, abdomen, arms and legs, respectively. The model is customizable, i.e. it meets individual characteristics of the neonate (e.g. gestational age, postnatal age, weight and length) which play an important role in heat transfer mechanisms. The model was validated during thermal neutrality and in a transient thermal environment.ResultsDuring thermal neutrality the model accurately predicted skin and core temperatures. The difference in mean core temperature between measurements and simulations averaged 0.25±0.21 °C and that of skin temperature averaged 0.36±0.36 °C. During transient thermal conditions, our approach simulated the thermoregulatory dynamics/responses. Here, for all infants, the mean absolute error between core temperatures averaged 0.12±0.11 °C and that of skin temperatures hovered around 0.30 °C.ConclusionsThe mathematical model appears able to predict core and skin temperatures during thermal neutrality and in case of a transient thermal conditions.     

Observations and comments on the body temperatures of some New Zealand reptiles

Abstract

Rectal body temperatures (BTs) of tuataras (Sphenodon punctatus) and of endemic, ovoviviparous gekkonid lizards—mainly Hoplodactylus maculatus (=H. pacificus) and Heteropholis manukanus—were taken together with ambient temperatures during early summer 1970 in areas of central New Zealand. The results, combined with earlier data, enable a number of conclusions to be drawn. (a) The preferred body temperature of heliotherm reptiles is best deduced from the mode of rectal BTS taken in the field, but that of non-heliotherms, when unimodal, from the median or mean. (b) Among Gekkonoidea, specific thermal relations are highly variable in several ways. (c) Sphenodon foraged on cool nights at BTs of 10.5–12.5°c, yet basked in the forest by day at BTs up to 24°c; in pasture it apparently basks within the burrow entrance. (d) Similarly, H. maculatus foraged at night at BTs of 10–13°c, but by day thermoregulated at BTs up to 33°c by ‘indirect basking’ (under thin cover) or ‘protected basking’ (in crevices penetrated by solar radiation). The average BT of females was 2°c higher than that of males, presumably because many females were gravid. (e) H. manukanus is (tertiarily) diurnal, and thermoregulated by basking up to a BT of 31 °c. Towards evening it apparently cooled down voluntarily. (f) Whereas a high daytime BT probably assists digestion in nocturnal foragers, a voluntary low night-time BT in diurnal reptiles may help to conserve energy.     

Effect of photoperiod and cold acclimation on survival of mice in cold

Male albino mice (Swiss-Webster) were raised at 5 °C under short (8L:16D) and long (16L:8D) light periods. All mice were housed in groups of three to five individuals in plastic mouse cages (16 × 12 × 28 cm) until 42 days of age with food and water ad libitum and cold exposed to ?40 °C between 10:00 am and 4:00 pm to determine survival time or time until loss of righting response occurred (CT min). Under short photo-periods, survival time was 49.3 ± 4.4 min and under long photoperiods it was 38.7 ± 1.9 min (P < 0.05). A second group of mice was maintained from birth at thermoneutral temperature (22 °C) under constant darkness, short day lengths (4L:20D), or constant light in the same fashion as mentioned above. When exposed to ?20 °C survival time was found to be 80.0 ± 5.0 min for the animals kept in constant darkness, 61.1 ± 2.3 min for animals raised in short photo-periods (4L:20D) (P < 0.01), and 52.4 ± 2.3 min for mice raised in constant light (P < 0.05). After 30 min mean rectal temperature was 32.1 ± 0.47 °C for constant-darkness animals, 30.5 ± 0.43 °C for short-day animals (P < 0.02), and 28.5 ± 0.74 °C for animals raised in constant light (P < 0.05). After 60 min mean rectal temperatures for constant-dark, 4L:20D, and constant-light animals were compared and body temperature was found to be 23.7 ± 1.6, 17.3 ± 1.5 (P < 0.01), and 12.8 ± 0.87 °C (P < 0.05), respectively. From these data, it is obvious that photoperiod influences cold resistance at both cold and thermoneutral acclimation temperatures although when considered individually, cold acclimation enhances cold survival to a greater degree than does reduced light exposure.     

Effect of freezing and thawing on the biomechanical characteristics of porcine ocular tissues

PurposeTo evaluate the effect of freezing and thawing on the biomechanical properties of ex-vivo porcine ocular tissue.MethodsThirty-six porcine eyes (18 pairs) were obtained fresh from a local abattoir and split into two groups of nine pairs to study the effect of storage at −20 °C and −80 °C. A randomly-selected eye from each pair (Control Group, CG) was tested fresh while the fellow eyes were frozen for 14 days, either at −20 °C and −80 °C (Frozen Group, FG) before thawing and testing. Seventy-two strips were extracted from the corneas and scleras of eye globes and subjected to uniaxial tension tests under loads up to 1.0 N. Following five preconditioning cycles, the load and elongation data obtained experimentally were analysed to derive the tissue’s stress-strain and tangent modulus-strain behaviour.ResultsCorneal tissue subjected to freezing at −20 °C exhibited significant increases in tangent modulus (mechanical stiffness) by 13 ± 17% (p = 0.003) at 1% strain and 14 ± 12% (p < 0.001) at 2% strain. In contrast, the increases in corneal stiffness at −80 °C were insignificant (6 ± 14%, p = 0.099 at 1% strain, 6 ± 15%, p = 0.091 at 2% strain). The corresponding increases in tangent modulus in the sclera were all insignificant (for −20 °C: 4 ± 14%, p = 0.265 at 1% strain, 3 ± 9%, p = 0.186 at 2% strain; for −80 °C: 3 ± 18%, p = 0.537 at 1% strain and 3 ± 18%, p = 0.491 at 2% strain).ConclusionsThe study provided evidence that freezing and thawing led to insignificant changes in ocular tissue stiffness except in corneal tissue that was frozen at −20 °C.     

Brown Adipose Tissue,Whole‐Body Energy Expenditure,and Thermogenesis in Healthy Adult Men

Brown adipose tissue (BAT) can be identified by ¹⁸F‐fluorodeoxyglucose (FDG)‐positron emission tomography (PET) in adult humans. Thirteen healthy male volunteers aged 20–28 years underwent FDG‐PET after 2‐h cold exposure at 19 °C with light‐clothing and intermittently putting their legs on an ice block. When exposed to cold, 6 out of the 13 subjects showed marked FDG uptake into adipose tissue of the supraclavicular and paraspinal regions (BAT‐positive group), whereas the remaining seven showed no detectable uptake (BAT‐negative group). The BMI and body fat content were similar in the two groups. Under warm conditions at 27 °C, the energy expenditure of the BAT‐positive group estimated by indirect calorimetry was 1,446 ± 97 kcal/day, being comparable with that of the BAT‐negative group (1,434 ± 246 kcal/day). After cold exposure, the energy expenditure increased markedly by 410 ± 293 (P < 0.05) and slightly by 42 ± 114 kcal/day (P = 0.37) in the BAT‐positive and ‐negative groups, respectively. A positive correlation (P < 0.05) was found between the cold‐induced rise in energy expenditure and the BAT activity quantified from FDG uptake. After cold exposure, the skin temperature in the supraclavicular region close to BAT deposits dropped by 0.14 °C in the BAT‐positive group, whereas it dropped more markedly (P < 0.01) by 0.60 °C in the BAT‐negative group. The skin temperature drop in other regions apart from BAT deposits was similar in the two groups. These results suggest that BAT is involved in cold‐induced increases in whole‐body energy expenditure, and, thereby, the control of body temperature and adiposity in adult humans.     

Brain temperature regulation of panting and non-panting pigeons exposed to extreme thermal conditions

• 1.1. Brain (hypothalamic), skin and body temperatures were measured in hand-reared acclimated (Acc, n = 5) and non-acclimated (NAcc, n =7) rock pigeons (Columba livia, mean body mass 237 g) exposed to increasing ambient temperatures (T_a) (30–60°C) and low humidities.
• 2.2. In non-panting Acc birds, brain temperature gradually increased from 40.1 ± 0.4°C at 30°C to 41.2 ± 0.4°C at 60°C T_a. A mean body temperature (T_b) of 41.2 ± 0.2°C was measured at T_a up to 50°C; an increase of 1.1°C was observed at 60°C (T_b 42.2 ±0.6°C).
• 3.3. In Acc panting birds exposed for 2 hr to 60°C, T_hy was 41.9 ± 0.8°C and T_s was somewhat (but insignificantly) higher, i.e., 42.2 ± 0.7°C. It looks as if both values were increased as a result of a slight hyperthermia that developed (T_b = 43.5 ± 0.9°C).
• 4.4. The significance of the present results for evaluating neuronal thermoresponsiveness of birds' hypothalamus is discussed.

     

Long-term drought effects on the thermal sensitivity of Amazon forest trees

The continued functioning of tropical forests under climate change depends on their resilience to drought and heat. However, there is little understanding of how tropical forests will respond to combinations of these stresses, and no field studies to date have explicitly evaluated whether sustained drought alters sensitivity to temperature. We measured the temperature response of net photosynthesis, foliar respiration and the maximum quantum efficiency of photosystem II (F_v/F_m) of eight hyper-dominant Amazonian tree species at the world's longest-running tropical forest drought experiment, to investigate the effect of drought on forest thermal sensitivity. Despite a 0.6°C–2°C increase in canopy air temperatures following long-term drought, no change in overall thermal sensitivity of net photosynthesis or respiration was observed. However, photosystem II tolerance to extreme-heat damage (T₅₀) was reduced from 50.0 ± 0.3°C to 48.5 ± 0.3°C under drought. Our results suggest that long-term reductions in precipitation, as projected across much of Amazonia by climate models, are unlikely to greatly alter the response of tropical forests to rising mean temperatures but may increase the risk of leaf thermal damage during heatwaves.     

Effects of temperature and photoperiod on ovarian recrudescence in the cyprinid fish Mirogrex terrae-sanctae

Mirogrex terrae-sanctae is a commercial, sardine-like cyprinid fish in the Sea of Galilee. The fish spawns from December to the end of March. Females collected at the quiescent phase of the cycle (June) were exposed to four combinations of photoperiod and temperature for 3 months. The highest GSI (2.44 ± 0.22) was found in females exposed to simulated winter conditions (16°C, 9L) while the lowest GSI (0.65 ± 0.04) was found in fish exposed to simulated summer conditions (27°C, 14L). The GSI of fish maintained at the unnatural combination of 16°C, 14L (1.30 ± 0.09) did not differ from that of fish maintained at the other unnatural combination of 27°C, 9L (1.07 ± 0.11). However, histological examinations revealed that vitellogenic oocytes were present only in fish maintained at low temperature regimes, which implies that the growth of the ovarian mass in the 27°C, 9L group was due mainly to oogonial proliferation and that vitellogenesis was inhibited in Mirogrex at a high temperature. Both protein and calcium concentrations increased in the serum of fish following injections of oestradiol-17β. The increase of calcium was evident only in the non-filtrable (bound) fraction, suggesting that the total serum calcium above 13 mg% could be used as an indirect parameter for circulating vitelloprotein. Fish collected at the quiescent phase were injected with oestradiol (50 μg/fish c. 15 g body weight) and subsequently transferred to tanks maintained at either 12°, 20° or 27°C. The total serum calcium increased to 23.0 ± 1.75 mg% in the fish maintained for 8 days at 20°C. This was significantly higher than the concentration of calcium in the serum of fish maintained at either 12°C (7.8 ± 0.52) or 27°C(l1.8 ± 0.77). This implies that the temperature may affect ovarian recrudescence by modulating the response of the liver to oestrogen, allowing the oestrogen-induced vitellogenesis to be relatively high in the cool environment during winter.     

Effect of temperature on development and reproduction of Neoseiulus barkeri (Acari: Phytoseiidae) fed on Aleuroglyphus ovatus

The effect of five constant temperatures (16, 20, 24, 28 and 32°C) on the development, survival and reproduction of Neoseiulus barkeri Hughes fed on Aleuroglyphus ovatus Toupeau (Acari: Acaridae) was examined in the laboratory at 85% relative humidity. Development time of different immature stages decreased with increasing temperature, total egg-to-adult development time varied from 5.0 ± 0.13 to 17.5 ± 0.29 days. The lower thermal threshold for development was 9.7 ± 2.48°C and the thermal constant from egg to adult was 111.1 ± 12.34 degree-days. Pre- and post-oviposition period and female longevity all shortened as temperature increased. The longest oviposition period was observed at 24°C with 20.4 ± 1.13 days. At 20, 24, 28 and 32°C, mated females laid on average 0.7 ± 0.08, 1.5 ± 0.04, 1.6 ± 0.11 and 1.5 ± 0.11 eggs per day, respectively, but no eggs were laid at 16°C. Both the maximum fecundity (30.9 eggs per female) and the highest intrinsic rate of increase (r _m = 0.166) were obtained at 28°C. The results of this study indicated that a mass rearing of N. barkeri with A. ovatus as prey is feasible at the appropriate temperature.     

Seasonal variations in basal metabolic rate, lower critical temperature and responses to temporary starvation in the arctic fox (Alopex lagopus) from Svalbard

Metabolic rates of four resting, post-absorptive male adult summer- and winter-adapted captive arctic foxes (Alopex lagopus) were recorded. Basal metabolic rates (BMR) varied seasonally with a 36% increase from winter to summer, while body mass was reduced by 17% in the same period. The lower critical temperature (T _1c) of the winter-adapted arctic fox was estimated to −7°C, whereas T _lc during summer was 5°C. The similarity of these values, which are much higher than hitherto assumed (e.g. Scholander et al. 1950b), is mainly due to a significantly (P<0.05) lower BMR in winter than in summer. Body core (stomach) temperature was stable, even at ambient temperatures as low as −45°C, but showed a significant (P<0.05) seasonal variation, being lower in winter (39.3±0.33°C) than in summer (39.8±0.16°C). The thermal conductivity of arctic fox fur was the same during both seasons, whereas the thermal conductance in winter was lower than in summer. This was reflected in an increase in fur thickness of 140% from summer to winter, and in a reduced metabolic response to ambient temperatures below T _lc in winter. Another four arctic foxes were exposed to three periods of forced starvation, each lasting 8 days during winter, when body mass is in decline. No significant reduction in mass specific BMR was observed during the exposure to starvation, and respiratory quotient was unchanged at 0.73±0.02 during the first 5 days, but dropped significantly (P<0.05) to 0.69±0.03 at day 7. Locomotor activity and body core (intraperitoneal) temperature was unaltered throughout the starvation period, but body mass was reduced by 18.5±2.1% during these periods. Upon re-feeding, locomotor activity was significantly (P<0.05) reduced for about 6 days. Energy intake was almost doubled, but stabilised at normal levels after 11 days. Body mass increased, but not to the level before the starvation episodes. Instead, body mass increased until it reached the reduced body mass of ad libitum fed control animals. This indicates that body mass in the arctic fox is regulated according to a seasonally changing set point.     

Effects of temperature on the growth and microstructure formation of cuttlebone from cuttlefish Sepia pharaonis

ABSTRACT

This study investigated the effects of three temperatures (20°C, 27°C, and 31°C) on the physiological performance (survival and growth) and cuttlebone micromorphological features (chamber number, chamber height and lamellae number) of cuttlefish Sepia pharaonis. We examined gross morphological characteristics of the internal calcareous cuttlebone to determine whether lamellar matrix was impacted by temperature. Juvenile survival was significantly affected by temperature (χ²?=?54.580, df?=?2, P?<?0.001). Cuttlebone weight, length and width were also positively correlated with temperature. Scanning electron microscopy revealed that a single chamber structure consists of septa, lamellae and pillars. At 20°C the chamber number of 89.0?±?10.8 was significantly higher than at 27°C with 44.8?±?3.6 or 31°C with 47.5?±?4.3 (Kruskal–Wallis [KW], χ^2?=?26.391, df?=?2, P?=?0.0001), whilst chamber height was lower at 20°C (KW χ^2?=?27.842, df?=?2, P?=?0.0001). Moreover, lamellae number varied among the treatments (KW χ^2?=?22.411, df?=?2, P?=?0.0002). Lamellae numbers at 20°C, 27°C and 31°C were 3–6, 6–9 and 5–8, respectively. The results indicated that the intrinsic lamellar matrix structure was significantly affected by temperature and that this effect may be used in cuttlebone growth studies.     

The relative roles of the parasol-like tail and burrow shuttling in thermoregulation of free-ranging Cape ground squirrels,Xerus inauris

As small arid-zone mammals, Cape ground squirrels (Xerus inauris) are unusual in being diurnally active. It is postulated that they remain active during the day by using their parasol-like tails to shade their bodies whilst foraging. However, no studies have continuously measured body temperature to determine the effect of using the tail as a parasol, relative to other thermoregulatory behaviours, such as burrow retreat. We caught four free-ranging Cape ground squirrels (673 ± 36 g) and surgically implanted miniature temperature-sensitive data loggers into their abdomens, to record body temperature every 5 min to an accuracy of 0.04 °C, before they were released back into their home range and observed for two weeks. Mean daily peak black globe temperature was 41 °C, and daily peak body temperature reached 40 °C. Ground squirrels raised their tails significantly more often at globe temperatures above 30 °C, but raising the tail did not decrease body temperature, nor prevent body temperature rising. Ground squirrels retreated to burrows, at 18 °C, significantly more often at high body temperatures and body temperature dropped 1–2 °C before re-emergence. We believe that the tail was raised to provide thermal comfort during high solar radiation exposure, and that burrow retreat was employed to dissipate a heat load and remain active diurnally.     

Functional response of a parasitoid Ganaspidium utilis （Hymenoptera： Eucoilidae） on the leafminer Liriomyza trifolii （Diptera： Agromyzidae）

Functional response of a solitary, larval-pupal endoparasitoid of Liriomyza leafminers, Ganaspidium utilis Beardsley, was estimated on Liriomyza trifolii Burgess at three temperatures （17℃, 25℃, 29℃ ） and host densities. A type Ⅱ random parasitoid equation （RPE） was used to estimate instantaneous search rate and handling time. The instantaneous search rate increased as temperature increased. All of the RPE regressions obtained for functional response of G. utilis at different temperatures were significant （P〈0.01）. The slope of RPE regression lines was lower across the temperatures. At 29±2℃, the maximum number of larvae parasitized was 7.8 per day. It decreased to 7.2 larvae parasitized at 25±2℃. At 17±2℃, no significant increment of parasitization was observed due to the host density increments. The estimated handling time was lowest at 17±2℃ and highest at 25 ± 2℃, respectively. The ability of G. utilis to find and parasitize L. trifolii over a wide range of temperatures makes them a good candidate for biological control of Liriomyza leafminers.