Effects of development, temperature and salinity on metabolism in eggs and yolk-sac larvae of milkfish, Chanos chanos (Forsskål)

Oxygen uptake rates and yolk-inclusive dry weiGhts were measured during the egg and yolk-sac larval stages of milkfish, Chanos chanos (Forsskal). Oxygen uptake by eggs and yolk-sac larvae was measured to assess the effects of four salinities (20,25,30,35 ppt) at 28°C. The effects of three temperatures (23,28,33°C) on oxygen uptake by yolk-sac larvae were determined at a salinity of 35 ppt. Dry weights were measured throughout embryonic development at 28°C and the yolk-sac stage at 23.28 and 33°C.
Oxygen uptake rates of eggs increased more than fivefold during embryogenesis (0.07±0.03 to 0.40 ± 03 μl O₂ egg ⁻¹ h ⁻¹;blastula to prehatch stage). Larval oxygen uptake did not change with age but was affected by rearing temperature (0.33 ± 0.08, 0.44 ± 0.07 and 0.63 ± 0.13 μl O₂ larva ⁻¹ h⁻¹ at 23, 28 and 33°C, respectively; Q₁₀= 1.93). Acute temperature changes from 28 to 33°C caused significant increases in oxygen uptake by embryos (Q ₁₀= 1.69–3.58) and yolk-sac larvae (Q ₁₀=2.55). Salinity did not affect metabolic rates.
Dry weight of eggs incubated at 28°C decreased 13% from fertilization to hatching. Incubation temperatures from 23–33°C did not affect dry weights at hatching. Rearing temperatures significantly affected the rate of larval yolk absorption (Q ₁₀= 2.25).     

Influence of temperature on egg hatching, growth and survival of larvae of Heterobranchus longifilis Val. 1840 (Teleostei: Clariidae)

Eggs of Heterobranchus longifilis Val. 1840 were artificially fertilized and incubated at a range of temperatures (20, 23, 25, 27, 29 and 32°C). The time from fertilization to hatching decreased with increasing temperature. No eggs survived to hatch at 20 and 32°C incubation temperatures, while at 23 and 29°C hatching was only minimal. Optimum hatching was obtained at 25 and 27°C, which corresponds to the ambient temperature range during the breeding season. Larvae of H. longifilis were reared for 11 days post-hatching at 20, 25, 27, 29 and 32°C. Growth increased with temperature (P < 0.05), whereas survival depicted an inverse relationship. Growth was minimal at 20°C and larvae rarely survived to the end of the experiment. Optimum temperature for the primary nursing of H. longifilis larvae was within the 25–27°C temperature range.     

Effects of temperature on developmental performance, survival and growth of sea lamprey embryos

This study assesses the influence of thermal regime on the development, survival rates and early growth of embryos of sea lamprey Petromyzon marinus incubated at five constant temperatures (7, 11, 15, 19 and 23° C). The time from fertilization to 50% hatching and from hatching to 50% burrowing were inversely related to incubation temperature. All the embryos incubated at 7° C died at very early stages, while those maintained at 11° C did not attain the burrowing stage. Survival from fertilization to hatching was 61, 89, 91 and 89% at 11, 15, 19 and 23° C, decreasing to 58, 70 and 70% from hatching to burrowing at 15, 19 and 23° C, respectively. Larvae reared during the first 3 months of exogenous feeding in a common environment at constant 21° C, revealed maximum survival for an incubation temperature of 15° C (43% of burrowed larvae) decreasing strongly at 19° C (16%) and 23° C (one suvivor among 240 larvae). Body length at the burrowing stage was maximum for embryos incubated at 19° C, but body mass increased in the interval 15–23° C. Mean incubation temperatures experienced by 117 broods during the embryonic development in the source river were estimated in 15·3±2·30° C and 16·7±1·76° C (mean±1 s.d .) for the periods fertilization-to-hatching and hatching-to burrowing, respectively.     

Interspecific and intraspecific variations in egg hatching for British populations of the stoneflies Siphonoperla torrentium and Chloroperia tripunctata (Plecoptera: Chloroperiidae)

SUMMARY 1. The objective was to compare variations in egg hatching between the two species (interspecific variations) and between populations of the same species (intraspecific variations). There were significant interspecific, but not intraspecific, differences in female size, adult life-span, egg production, hatching success, incubation periods and hatching periods.
2. The optimum temperature for hatching success within the range 3.8–22.1°C in the laboratory and the range over which at least 50% of the eggs hatched were lower for Chloroperia tripunctata (Scopoli) (8.5°C, 4.2–17.3°C) than for Siphonoperla torrentium (Pictet) (12.8°C, 6.1–19.4°C). Few eggs hatched at 22.r°C.
3. The relationship between incubation period (d days) and water temperature (T°C) was given by: d=1219/T^1.368 for S. torrentium , d=253/T^0.459 for C. tripunctata . Both equations successfully predicted incubation periods for eggs placed in a stream. The period over which eggs hatched was much longer for C. tripunctata than for S. torrentium at all temperatures.
4. The shorter incubation period (at r>5.6°C) and shorter hatching period for S. torrentium ensure that larvae of this species are already growing when eggs of C. tripunctata start to hatch, but the prolonged hatching period of the latter species ensures a long period of larval recruitment to the population. These differences in egg hatching may reduce competition between the two closely-related species.     

TEMPERATURE REQUIREMENTS FOR THE DEVELOPMENT AND SURVIVAL OF RICE STEMBORERS IN LABORATORY CONDITIONS

Abstract  The effect of seven constant temperatures from 10 to 40°C (10, 15, 20, 25 30, 35 and 40°C) on the development of eggs, larvae and pupae of rice stemborers viz., Chilo polychrysa (Meyrick), C. suppressalis (Walker), C. partellus (Swinhoe), Scirpophaga incertulas (Walker), S. innotata (Walker) and Sesamia inferens (Walker) were studied. The mean developmental period among constant temperatures (in days) of egg, larva and pupa of six borers differed significantly ( P < 0.0001). The mean percent of development per day of egg, larva and pupa of all borers gradually increased with the increase of constant temperatures. The total developmental period was inversely decreased with the increase of constant temperatures. The lower threshold temperature was found between 10–15°Cand higher threshold temperature between 35–40°C, where no development took place. The mean developmental zero was 8.57±1.71, 7.70±1.01, 8.56±3.25, 10.19±2.19, 8.64±2.68 and 7.91±0.82 for egg, larva and pupa of above-mentioned borers respectively. The total thermal constant of egg, larva and pupa was 705.56, 725.32, 703.30, 556.59, 655.34 and 837.95 degree- days for C. polychrysa, C. suppressalis, C. partellus, S. incertulas, S. innotata and S. inferens respectively. The degree- days required for oviposition of female moths of the six borers was calculated as 99.06, 90.85, 99.29, 75.16, 92.25 and 80.41 respectively. The total degree- days required completing a generation was 804.62, 816.17, 802.59, 631.75, 648.84 and 918.36 respectively.     

Biology and life table parameters of the mushroom pest, Pediculaster fletchmanni （Acari： Siteroptidae）, at three constant temperatures

This paper is concerned with the bionomics and demography of Pediculaster fletchmanni Wicht （Acari： Siteroptidae） under controlled conditions （20 ± l, 22 ± 1 and 25 ± 1℃, 70% ± 5% relative humidity and a photoperiod of 16L ： 8D hours）. Glass Petri dishes inoculated with Trichoderma sp. mycelia were used as substrate and food source. The mean developmental time of the egg and the active larva did not differ significantly at the various constant temperatures, but these periods were significantly different for the quiescent larval stage. The preoviposition period ranged from 2.3 to 2.8 days, the ovipositional period increased with temperature increase, and all females died immediately after oviposition. The development of active larvae was the fastest of all life stages. The developmental threshold ranged between 5.25-14.22℃ the highest value being observed for the quiescent larval development. For immature development required 89.29 degree-days. Values of rm （intrinsic rate of increase） were 0.229, 0.398 and 0.386 for 20, 22 and 25℃ respectively. Finite rates of increase （λ） increased along with increasing temperature from 20-25℃ consequently the population doubling time （D） and mean generation time （T） showed significant differences with increasing temperature.     

Relationships between maternal size, egg diameter, time of spawning season, temperature, and length at hatch of Atlantic silverside, Menidia menidia

Eggs were stripped from gravid Atlantic silversides collected on two occasions, once during the early part and once during the late part of the natural spawning season. Unfertilized egg diameter was not correlated with length of the female, nor was it significantly larger during the early part of the season. Eggs were fertilized and incubated in the laboratory. Larval length at hatch was measured every 24 h during the hatching period after embryos were incubated at 18 or 25° C. Lower incubation temperature caused a significantly greater length at hatch for the offspring of each of the 20 females studies. In most cases (17 out of 20 at 25° C, 10 out of 20 at 18° C), there was a significant decrease in length at hatch during the hatching period for a given female's eggs incubated at a given temperature. In the natural environment, larvae hatched early in the season under cooler temperatures could average 12% longer than those hatched later under warmer temperatures, and therefore may have a greater chance of survival. The results help to explain the observation that field-caught M. menidia that hatched early in the season are larger at any given age than those that hatched late in the season.     

Temperature-dependent development and survival of the lesser mealworm, Alphitobius diaperinus

Abstract. Development, growth and survival of the lesser mealworm, Alphitobius diaperinus (Panzer), were determined at six constant temperatures. No egg hatch or larval development occurred at 17^oC. At temperatures of 20, 25, 30, 35 and 38^oC the median development times (days), respectively, were for eggs (13.4, 6.0, 4.4, 2.6 and 2.6), larvae (133.0, 46.0, 26.2, 22.4 and 23.9), pupae (17.0, 8.0, 5.5, 4.0 and 4.1), and from oviposition to adult emergence (164.4, 60.2, 37.9, 29.0 and 30.8). The Sharpe & DeMichele (1977) model was used to describe the temperature-dependent development. The mean egg survival (hatching) ranged from 61% to 86%, with lowest hatch at 20^oC. Survival of the larvae and pupae ranged from 32% to 73% and from 85% to 95%, respectively, with lowest survival at 20^oC. Pupae had significantly lower weights at 35^oC and adults at 38^oC than at the other temperatures. Female pupae (20 mg) and female adults (16 mg) were significantly heavier than male pupae (17 mg) and male adults (13 mg). Adults (0.5–9 months old) laid 4–7 eggs per female per day at 25^oC.     

The effect of temperature on development and hatching of scad, Trachurus trachurus L., eggs

The effect of temperature on the rates of development and hatching of artificially fertilized eggs of the scad, Trachurus trachurus L., was studied using a thermal gradient incubator. Development of eggs through to hatching occurred within the temperature range 10.5–21.2° C, with greatest survival between 12.2 and 15.8° C. The mean egg diameter was 0.94 mm and mean length of larvae on hatching 2.46 mm. Regressions of development time on mean incubation temperature are presented. The data are compared with those reported in the literature and related to sea temperatures in scad spawning grounds.     

Morphological development and allometric growth patterns in hatchery-reared California halibut larvae

Morphological development, allometric growth and behaviour of hatchery-reared California halibut Paralichthys californicus were studied from hatching to metamorphosis (42 days post hatch, dph) at 187° C. Mean standard length ( L _S) of larvae and juveniles increased from 2.1 mm at hatching to 10.5 mm at metamorphosis with the increase in length being approximately linear. Stages of morphological development were described using the alphabetic staging (A–I) used for other flatfish species. Organogenesis and differentiation were more rapid and complex in yolk-sac (hatching, stage A–3 dph, stage B), preflexion (3–19 dph, stages B–C), and flexion larvae (from 20 to 23 dph, stages D–E), as larvae developed most of their sensory, feeding, respiratory and swimming systems. After notochord flexion at 24–25 dph (stage F), most morphological changes were related to the progressive transformation from a bilateral symmetrical larva to an asymmetrical benthic juvenile (42 dph, stages G–I).     

Hypoxia, low salinity and lowered temperature reduce embryo survival and hatch rates in black bream Acanthopagrus butcheri (Munro, 1949)

Embryo survival and hatch rates were measured in black bream Acanthopagrus butcheri exposed to different treatments of dissolved oxygen: hypoxic and normoxic, three salinities: 15, 23 and 35 and two temperatures: 16 and 20° C. Hypoxic conditions (50% saturation) reduced 1 day embryo survival by up to 15% ( P < 0·05) compared to embryos held in normoxic (>80% saturation) conditions. Temperature had no effect on the survival of embryos in these treatments, however, lowered salinity significantly reduced embryo survival at 20° C, but not at 16° C. Mean hatch rates were reduced by 10–28% in hypoxic treatments ( P < 0·05) and lowered salinity treatments ( P < 0·05). Hatching was delayed by up to 24 h at 16° C and very low (or zero) hatching occurred in hypoxic treatments at salinities of 15 and 23. These results confirm that environmental conditions in estuaries are important factors in determining spawning success of black bream and are discussed in relation to global warming and climate change that are likely to alter the physical conditions in southern Australian estuaries.     

Synchronization of larval emergence in winter moth (Operophtera brumata L.) and budburst in pedunculate oak (Quercus robur L.) under simulated climate change

1. The hypothesis that a 3 °C elevation in temperature and doubled CO₂ concentration would have no effect on the synchronization of winter moth egg hatch with budburst in oak was tested by comparing the separate and interactive effects of ambient and elevated (+ 3 °C) temperature and ambient and elevated (doubled to 340 p.p.m.) CO₂ in eight experimental Solardomes. In addition, an outdoor control was compared with the ambient temperature/CO₂ treatment combination.
2. Elevated temperature accelerated darkening (preceding egg hatch by about 5–10 days) and hatching of eggs developing off the trees; elevated CO₂ had no effect. The same effects were observed in eggs developing on the trees.
3. Within treatments, date of egg hatch was the same on trees with early or late budburst.
4. Egg darkening and budburst were closely synchronized at both ambient and elevated temperatures.
5. Both eggs and trees required fewer cumulative heat units (day degrees > 4 °C), for hatching and budburst, respectively, at ambient than elevated temperatures. The requirements in the outdoor control treatment were similar to those in the ambient Solardome treatment.
6. Egg hatch between 10 and 25 °C, on a temperature gradient in the laboratory, required a constant number of heat units; fewer were required below 10 °C.
7. Elevated temperatures, in the Solardomes and the field, delayed adult emergence from the pupae.
8. The results suggest that a general increase in temperature with climatic change would not affect the closeness of the synchronization between egg hatch of winter moth and budburst of oak.     

Development time and survival of Verrallina funerea (Theobald) (Diptera: Culicidae) immatures and other brackish water mosquito species in southeast Queensland, Australia

Abstract  Verrallina funerea (Theobald) is a brackish water mosquito that is recognised as an important pest and vector in southeast Queensland, Australia. Immature development time and survival of Ve. funerea was defined in the laboratory in response to a range of temperatures (17–34°C) and salinities (0–35 parts per thousand (p.p.t)). The expression of autogeny in this species was also assessed. Salinity only had a slight effect on mean development time from hatching to adult emergence (7.0–7.4 d at salinities of 0, 17.5 and 31.5 p.p.t) and survival was uniformly high (97.5–99.0%). Mean development times were shorter at 26, 29 and 32°C (7.0, 6.8 and 6.8 d, respectively) and longest at 17°C (12.2 d). The threshold temperature ( t ) was 5.8°C and the thermal constant ( K ) was 142.9 degree-days above t . Survival to adulthood decreased from >95% (at 17–29°C) to 78% (at 32°C) and 0% (at 34°C). No expression of autogeny was observed. Immature development times of Ve. funerea , Ochlerotatus vigilax (Skuse) and Oc. procax (Skuse) were then determined under field conditions at Maroochy Shire. Following tide and rain inundation, cohorts of newly hatched larvae were monitored daily by dipping, and time until pupation was noted. Tidal inundation triggered hatching of Ve. funerea and Oc. vigilax larvae whereas Oc. procax larvae were found only after rain inundation. Estimates of Ve. funerea and Oc. vigilax field development times were similar (8–9 d) while Oc. procax development time was slightly longer (9–10 d). Based on these survey results, control activities targeting Ve. funerea must be initiated 4 d (if using Bacillus thuringiensis var. israelensis de Barjac) or 5 d (if using s -methoprene) after inundation. However, Casuarina glauca Sieber canopy and branchlets covering breeding habitats may present a problem for the penetration of such treatments.     

Effect of temperature on development rate and fecundity of apterous Aphis gossypii Glover (Hom., Aphididae) reared on Gossypium hirsutum L.

The developmental time, survival and reproduction of the cotton aphid, Aphis gossypii Glover (Hom., Aphididae), were evaluated on detached cotton leaves at five constant and two alternating temperatures (15, 20, 25, 30, 35, 25/30, and 30/35°C). The developmental periods of the immature stages ranged from 12.0 days at 15°C to 4.5 days at 30°C. A constant temperature of 35°C was lethal to the immature stages of A. gossypii. The lower developmental threshold for the cotton aphid was estimated at 6.2°C and it required 108.9 degree-days for a first instar to become adult. The average longevity of adult females was reduced from 39.7 days at 15°C to 12.6 days at 30/35°C. The average reproduction rate per female was 51.5 at 25/30°C and 20.9 at 30/35°C. Mean generation time of the population ranged from 10.4 days at 30°C to 24.5 days at 15°C. The largest per capita growth rate ( r _m = 0.413) occurred at 30°C, the smallest at 15°C ( r _m = 0.177). It was evident that temperatures over 30°C prolonged development, increased the mortality of the immature stages, shortened adult longevity, and reduced fecundity. The optimal range of temperature for population growth of A. gossypii on cotton was 25/30–30°C.     

Eggs in autumn: responses to declining incubation temperatures by the eggs of montane lizards

Facultative hatching in response to environmental cues may increase the viability of offspring, if the cue that stimulates hatching also predicts the negative consequences of delayed emergence. Declining incubation temperatures might provide such a cue for montane lizards, because eggs that fail to hatch before winter will perish in the nest. I tested this idea by incubating eggs of an alpine scincid lizard ( Bassiana duperreyi ) in the laboratory. For the first half of the incubation period the eggs were kept at nest temperatures typical of those experienced in summer in the field (daily cycle of 18 ± 7.5°C). I then transferred eggs at weekly intervals into cooler regimes (either 15 ± 7.5°C; or with daytime temperatures unchanged but dropping to 0°C overnight). Contrary to prediction, the eggs did not hatch early. However, transfer to lower temperatures caused only a relatively short delay in hatching, because of a virtual temperature-independence of developmental rates late (but not early) in incubation. Decreasing incubation temperatures also modified hatchling running speeds and post-hatching growth rates, even if the thermal decrease occurred only shortly before the usual time of hatching. These processes plausibly affect hatchling fitness in cold-climate reptiles, and might be adaptations to montane habitats. Alternatively, they may prove to be widespread in other (warmer-climate) reptile taxa, in which case no adaptive hypothesis need be proposed. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 76 , 71–77.     

Effects of temperature on the development and survival of an endangered butterfly, Shijimiaeoides divinus barine (Leech) (Lepidoptera: Lycaenidae)

The effects of temperature on the development and survival of Shijimiaeoides divinus barine were examined in the laboratory in 2008. The eggs and larvae were reared at temperatures of 15, 17.5, 20, 25, 30 and 35°C with a long-day photoperiod of 16 h light : 8 h dark (16L : 8D). The highest hatchability of eggs was 88.0% at 20°C, but hatchability at high temperatures of 30 and 35°C was 30 and 0%, respectively. The lowest and highest survival rates from the first to third instar were 18.8% at 15°C and 76.9% at 20°C. Few deaths were observed after the fourth instar. The shortest developmental periods of the eggs and larvae were 4.0 and 15.8 days at 30°C, and the durations of the egg and larval stages increased significantly as the temperature decreased. The developmental zero and thermal constants were 9.6°C and 82.6 degree–days for the egg stage, and 10.7°C and 306.8 degree–days for the larval stage. The developmental period of the natural population of S. divinus barine in Azumino City, Nagano Prefecture was calculated using the developmental zero, thermal constants and Azumino City temperature data.     

短时高温对加州新小绥螨发育的影响

为了探究高温逆境条件下加州新小绥螨的生存特性对其种群发育的影响,利用短时高温刺激试验,研究加州新小绥螨卵、幼螨、雌成螨在35、38、42、45 ℃等4个温度下、处理1～8 h后的孵化率、存活率、后期发育历期及繁殖的影响.结果表明: 处理温度越高,时间越长,卵和幼螨的存活率越低,其后续发育历期随处理温度升高和时间增加先缩短后延长.当温度为38 ℃,处理8 h后,卵的后续发育历期最短,为4.1 d.卵在45 ℃下处理2 h以上将不能正常孵化,而幼螨在45 ℃下处理8 h后不能存活;雌成螨产卵期和产卵量基本随温度升高先增加后降低,35 ℃处理8 h后,单雌产卵量最高,为38.9粒;38 ℃处理8 h后,单雌产卵量为36.7粒;45 ℃处理8 h后,单雌产卵量仅为14.5粒.短时高温主要影响加州新小绥螨的孵化率、存活率和后续发育历期,对雌成螨的产卵前期和存活率影响较小.     

短时高温对加州新小绥螨发育的影响

为了探究高温逆境条件下加州新小绥螨的生存特性对其种群发育的影响,利用短时高温刺激试验,研究加州新小绥螨卵、幼螨、雌成螨在35、38、42、45 ℃等4个温度下、处理1～8 h后的孵化率、存活率、后期发育历期及繁殖的影响.结果表明: 处理温度越高,时间越长,卵和幼螨的存活率越低,其后续发育历期随处理温度升高和时间增加先缩短后延长.当温度为38 ℃,处理8 h后,卵的后续发育历期最短,为4.1 d.卵在45 ℃下处理2 h以上将不能正常孵化,而幼螨在45 ℃下处理8 h后不能存活;雌成螨产卵期和产卵量基本随温度升高先增加后降低,35 ℃处理8 h后,单雌产卵量最高,为38.9粒;38 ℃处理8 h后,单雌产卵量为36.7粒;45 ℃处理8 h后,单雌产卵量仅为14.5粒.短时高温主要影响加州新小绥螨的孵化率、存活率和后续发育历期,对雌成螨的产卵前期和存活率影响较小.     

Temperature-induced changes of survival, development and yolk partitioning in Chondrostoma nasus

Fertilized Chondrostoma nasus eggs were incubated at 10, 13, 16 and 19° C until full resorption of the yolk sac. High survival was observed at 10–16° C (89–92% at the onset of external feeding), whereas at 19) C survival was depressed (76%). The time at which 5, 50 and 95% of individuals had hatched, filled the swim bladder, ingested the first food and fully resorbed the yolk sac was determined. An increase in temperature accelerated development and made it more synchronous. Within the period from fertilization to hatching embryonic development was theoretically arrested (t_{0 dev}) at 8·8° C, and growth was arrested (t_0gr) at 8·86° C. For the whole endogenous feeding period (from fertilization to full yolk resorption) the amount of matter transformed into tissue was temperature independent between 10° and 19° C. Respiration increased exponentially with age; the respiration increase was faster at higher temperatures, but, in general, metabolic expenditures of C. nasus were low. As a consequence, the efficiency of utilizing yolk energy for growth was high as compared with other fish species (57% during the whole endogenous feeding period); it was temperature independent. However, time was used less efficiently at low temperatures, increasing a risk of predation. Within the endogenous feeding period a shift from lower to higher temperatures for optimal yolk utilization efficiency was observed. The temperatures optimal for survival and energetic performance seem to be 13–16° C for egg incubation and 15–18° C for rearing of yolk-feeding larvae. Chondrostoma nasus is a potential candidate for aquaculture for restocking purposes.     

美洲斑潜蝇实验种群生命表的研究

在15、20、25、30和35℃五种温度下,观察了美洲斑潜蝇Liriomyza sativae Blanchard实验种群的发育历期、存活率、产卵量、寿命等,组建了实验种群生命表,估测了种群参数。结果表明：随温度升高发育历期缩短,在试验的温度范围内,卵、幼虫、蛹的历期变化分别为7.6～2.0天,12.7～2.9天,34.3～6.8天;成虫寿命变化为17.3～6.5天。卵、幼虫、蛹的发育起点温度分别为7.5℃,9.8℃,11.5℃,10.9℃,有效积温为3.9,52.7,128.5,229.9日度。在五种温度下,卵的存活率均在84.2%以上。幼虫除在15℃时存活率为66.7%外,其它温度均在94.6%以上,蛹的存活率变化幅度最大,25℃时为80.3%,35℃时仅为10.0%。30℃时种群的内禀增长力r_m最大,加倍时间最短,净生殖率最高。在20～35℃四种温度下种群的稳定年龄组配中未成熟阶段所占比例均在97%以上。