Energy metabolism and ATP free-energy change of the intertidal wormSipunculus nudus below a critical temperature

The intertidal wormSipunculus nudus was exposed to various temperatures for an analysis of the integrated changes in energy and acid-base status. Animals were incubated in sea water or maintained for up to 8 days at 4 and 0°C while dwelling in the sediment. Cannulation of the animals prior to experimentation allowed the analysis of blood gas parameters ( , and pH). fell to 0 torr within 8 days at 0°C. A simultaneous reduction of ventilatory activity was derived from measurements of the pattern of coelomic fluid pressure changes associated with ventilatory movements. The increase in and an onset of anaerobic metabolism, indicated by the accumulation of end products like acetate and propionate both in the coelomic fluid and the body wall musculature, led to the development of a progressive acidosis and a deviation from the alphastat regulation of intracellular pH seen in unburied animals. The drop in intracellular pH together with the depletion of the adenylates and the phosphagen, phospho-l-arginine, reflect a significant decrease in the Gibb's free-energy change of ATP hydrolysis. These changes are interpreted to indicate lethal cold injuries, because recovery was not possible when the animals were returned to 12°C after more than 2 days of exposure to 0°C. A low critical temperature indicating the onset of cold-induced anaerobiosis is concluded to exist below 4°C owing to the insufficient response of the ventilatory system to the developing hypoxia.     

Temperature‐dependent development of the European larch bark beetle,Ips cembrae

The temperature‐dependent development of the European larch bark beetle, Ips cembrae, was studied under long‐day conditions L:D 16:8 at three temperature regimes, 15°C, 20°C and 25°C, using the sandwich plate method. By observing the individual developmental progress, we calculated the developmental times and lower developmental thresholds of one entire generation and various ontogenetic stages. The mean developmental time of one generation was about 120, 64 and 37 days at 15°C, 20°C and 25°C, respectively. The egg stage comprised about 9% of the total development or about 16% of the pre‐imaginal development. The larval stages took about 39% of the entire and about 66% of the pre‐imaginal development. The pupal stage needed about 11% of the total or about 18% of the pre‐imaginal development. The lower developmental threshold for one generation was 11.2°C. The egg stage had the highest lower developmental threshold of 12.0°C, the pupa the lowest of 9.8°C and the total larval stages showed a value of 11.2°C. The thermal requirements for I. cembrae have never been studied in detail before. The results will be a valuable contribution for monitoring and risk assessment models to estimate the beetle's phenology and its potential impacts on forest ecosystems under changing climate conditions.     

Temperature related effects on embryonic development of the Mediterranean locust, Dociostaurus maroccanus

Laboratory studies were conducted to assess the effect of temperature on the development of the eggs of Dociostaurus maroccanus (Thunberg) (Orthoptera, Acrididae) during anatrepsis (stages I–XIV) and during catatrepsis (stages XV–XX). The developmental rates of anatrepsis were studied at five constant temperatures ranging from 10 to 30°C. Egg development occurred over the entire range but at 10°C the embryos were unable to complete anatrepsis. The relationship between temperature and developmental times for completing anatrepsis was analysed by the non‐linear Logan type III model. The optimal temperature estimated for the development of eggs during anatrepsis was 24.7°C; the lower and upper thermal thresholds were 9°C and 31°C, respectively. Once the embryos completed anatrepsis, only those incubated at 15°C continued morphogenesis beyond stage XIV (diapause stage) without a low‐temperature exposure period. The developmental rate of catatrepsis was studied at four constant temperatures ranging from 15°C to 30°C after exposure to low‐temperature, 10°C, for 30, 60 or 90 days. For catatrepsis, temperature and developmental time were linearly and inversely related. Linear regression was used to estimate the lower developmental threshold and the degree days requirements for catatrepsis. Both decreased with longer exposure to the low temperature; the former from 13.8°C to 10.5°C and the latter from 212.8 to 171.5 degree days, following 30 and 90 days at 10°C, respectively. Our results improve the ability of decision support systems for Mediterranean locust pest management by providing better forecasts to land managers and pest advisors.     

Life history of the importedScymnus (Nephus) Reunioni [Col.: Coccinellidae] predator of mealybugs

The life history ofNephus reunioni, introduced from the Reunioni island has been studied. Optimum temperature for the development of the entomophagous insect is 24–25°C. In this case the population has the highest survival at preimaginal stages, life duration of adults and reproductive capacity. The rate of population growth was calculated by the formula:

A series of stages in the embryonic development of Chelydra serpentina

Eggs of the common snapping turtle, Chelydra serpentina serpentina were incubated at 30°C and at 20°C. The incubation period at the higher temperature was about 63 days. At the lower temperature, the period was estimated to be 140 days. Lengths of the embryos at various times of development were recorded. A series of 26 stages is described. The staging is based on timed intervals at a constant temperature, 20°C.     

Effects of low temperatures on in vitro produced bovine zygotes

The objective of this research was to investigate the effects of cooling on the development of bovine zygotes. One-cell bovine embryos were maintained at 39°C (control), 20°C, 10°C, or 0°C for 5, 10, or 20 minutes, then cultured in vitro for 7 days and the proportion of embryos developing to the compact morula or blastocyst stage compared between different treatments. Duration of exposure time had no effect on development. Development rates to the compact morula or blastocyst stage were 3.9%, 11.4%, 17.4%, and 24.4% for zygotes maintained at 0°C, 10°C, 20°C, and 39°C, respectively, with differences in embryo yield between every treatment (P < 0.05). In a second experiment, bovine pronuclei (karyoplasts) and cytoplasts were cooled at 0°C or maintained at 39°C for 5 minutes. Pronuclear transplantation was then utilized to create 4 types of reconstructed embryos, those with: 1) non-cooled pronuclei and non-cooled cytoplasm, 2) non-cooled pronuclei and cooled cytoplasm, 3) cooled pronuclei and non-cooled cytoplasm, and 4) cooled pronuclei and cooled cytoplasm. The proportion of embryos developing to the blastocyst stage was highest when non-cooled pronuclei were transferred into non-cooled cytoplasm (18.9%), and similar to that of non-cooled, non-manipulated control zygotes (13.2%, P > 0.05). No embryos developed to the blastocyst stage when pronuclei (cooled or non-cooled) were transferred into cooled cytoplasm. However, zygotes with cooled pronuclei transferred into non-cooled cytoplasm yielded 4.5% blastocysts (P < 0.05). More embryos developed to the compact morula or blastocyst stage when non-cooled vs. cooled cytoplasm was utilized, regardless of whether the pronuclei were cooled (P < 0.05). These data demonstrate that pronuclei are more tolerant to low temperature exposure than is ovum cytoplasm. Mol. Reprod. Dev. 47:435–439, 1997. © 1997 Wiley-Liss, Inc.     

Biological traits of Epitrix papa (Coleoptera: Chrysomelidae: Alticinae), a new potato pest in Europe,and implications for pest management

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Growth and reproduction of the mosquitofish,Gambusia affinis,in relation to temperature and ration level: consequences for life history

The allocation of energy to growth and reproduction, in relation to temperature and food availability, was investigated in laboratory experiments with the mosquitofish,Gambusia affinis. At constant temperature of 20, 25 and 30°C and ad libitum feeding, specific growth rates increased with increasing temperature at 1.7, 3.1 and 3.4% dry mass day⁻¹, respectively. Growth rates in a cycling temperature regime (20–30°C, ) were faster than in a 25°C constant temperature. As temperature increased from 20 to 30°C, mean age at first reproduction decreased from 191 to 56 days and brood size and mass of offspring increased significantly. Interbrood interval was also temperature dependent; estimates at 25 and 30°C for females >1000 mg were 22.6 and 18.6 days, respectively. Interbrood interval could not be calculated at 20°C. Although fitness was highest at 30°C, females at 25°C invested a greater proportion of surplus energy (growth and reproduction) to reproduction (38%) than at 20 (17%) or 30°C (36%) during the 32-week study. Fish at cooler temperatures began reproduction at a smaller size. Where rations were controlled at low, medium, and ad libitum levels, somatic and gonadal growth increased with increasing temperatures and food availability. The proportion of energy invested in reproduction was highest at 25°C for each comparable ration level. Calculated energy budgets indicated that over the 10-week study, 17–22% of the food energy was invested in growth, 0–7% in reproduction, and 75–83% in respiration and excretory losses, depending on feeding and temperature conditions.     

A review of the history of research and control of <Emphasis Type="Italic">Rhipicephalus</Emphasis> (<Emphasis Type="Italic">Boophilus</Emphasis>) <Emphasis Type="Italic">microplus</Emphasis>, babesiosis and anaplasmosis in Uruguay

The effect of five constant temperatures (16, 20, 24, 28 and 32 °C) on the development, survival and reproduction of Tetranychus cinnabarinus (Boisduval) [=?Tetranychus urticae Koch (red form)] fed on cassava leaves was examined in the laboratory at 85% relative humidity. Development time of various immature stages decreased with increasing temperature, with total egg-to-adult development time varying from 27.7 to 6.7 days. The lower thermal threshold for development was 10.8 °C and the thermal constant from egg to adult was 142.4 degree-days. Pre- and post-oviposition period and female longevity all decreased as temperature increased. The longest oviposition period was observed at 20 °C with 20.4 days. Under different temperatures, mated females laid, on average, 1.0, 2.9, 4.7, 4.7 and 4.9 eggs per day, respectively. The maximum fecundity (81.5 eggs per female) was at 28 °C and the intrinsic rate of increase (r _m ) was highest (0.25) at 32 °C. The results of this study indicate that T. cinnabarinus population could increase rapidly when cassava leaves serve as a food source. At the appropriate temperature T. cinnabarinus could seriously threaten growth of cassava.     

Development rate and lower temperature threshold in the eggs of Eurygaster integriceps (Heteroptera: Scutelleridae)

The sunn pest, Eurygaster integriceps Put. has a wide distribution in the Palearctic region. It is the most important pest problem of wheat in Turkey. The objective of this study was to attain better knowledge of the development of the sunn pest eggs. The lower temperature threshold and development rate of eggs were determined at 17, 20, 23, 26 and 32°C ± 1°C in the laboratory. A linear model was used to describe the developmental rate and temperature. The egg development required 90.9 degree‐days above the theoretical threshold of 11.7°C. The development time was 17.6 ± 0.1 days at 17°C, and 4.5 ± 0.01 days at 32°C. Incubation time was inversely related to temperature. The study showed that the eggs of E. integriceps needed shorter periods of time to complete their development than immature stages of their parasitoids Trissolcus spp.     

Encarsia formosa parasitizing the Poinsettia-strain of the cotton whitefly,Bemisia tabaci, on Poinsettia: bionomics in relation to temperature

Adult longevity, developmental time and juvenile mortality ofEncarsia formosa Gahan (Hymenoptera:Aphelinidae) parasitizing the Poinsettia-strain ofBemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) on Poinsettia (Euphorbia pulcherrima Willd.) were investigated in laboratory experiments at three temperatures: 16 °C, 22 °C and 28 °C. Furthermore, the parasitoid's preference for different larval stages of the whitefly was determined at 24.5 °C. The lifespan ofE. formosa decreased with temperature from one month at 16 °C to nine days at 28 °C. A lower temperature threshold of 11 °C for adult development was found. The development of juvenile parasitoids inB. tabaci lasted more than two months at the lowest temperature, but was only 14 days when temperature was 28 °C. The lower temperature threshold for immature development was 13.3 °C, yielding an average of 207 day-degrees for the completion of development into adults. Juvenile mortality was high, varying from about 50% at 16 °C to about 30% at 22 °C and 28 °C.E. formosa preferred to oviposit in the 4th instar and prepupal stages ofB. tabaci followed by the 2nd and 3rd instars. The preference for the pupal stage was low. The parasitoid used all instars of the whitefly for hostfeeding, with no apparent differences between the stages. The average duration of the oviposition posture was four minutes. Demographic parameters were calculated from life tables constructed from the data. The intrinsic rate of increase (r _m) and the net reproductive rate (R ₀) increased with temperature from 0.0279 day⁻¹ at 16 °C to 0.2388 day⁻¹ at 28 °C and from about 12 at 16 °C to about 66 at 28 °C, respectively.     

Plant regeneration from microspore-derived embryos ofBrassica Napus: Effect of embryo age,culture temperature,osmotic pressure,and abscisic acid

Summary Microscope cultures ofBrassica napus cv. Topas undergo high frequency embryogenesis in vitro; however, the majority of microspore-derived embryos do not develop directly into plants but usually undergo abnormal development including the formation of secondary embryos on the hypocotyls. The present studies show that older embryos or embryos cultured at higher temperature (25° C) were more likely to undergo secondary embryogenesis whereas embryos cultured at 20° C or pretreated at 5° to 10° C for 28 days developed more readily into normal plants. Compared with embryos cultured at 25° C, those cultured at 20° C gave a threefold increase in normal plant production. Pretreatments at cooler temperatures (5° to 10° C) resulted in an additional two-to threefold increase in the recovery of normal plants. Higher osmoticum during pretreatment improved embryo survival at low temperatures but generally inhibited normal plant development. Abscisic acid was ineffective or deleterious.     

Effects of temperature on the development and survival of an endangered butterfly,Lycaeides argyrognomon (Lepidoptera: Lycaenidae) with estimation of optimal and threshold temperatures using linear and nonlinear models

The effects of temperature on the development and survival of Lycaeides argyrognomon were examined in the laboratory. The eggs, larvae and pupae were reared at temperatures of 15, 17.5, 20, 25, 30 and 33°C under a long‐day photoperiod of 16‐h light and 8‐h darkness. The survival rates of the first–third instars ranged from 40.0 to 82.4%. The mortalities of the fourth instar were lower than those of the first–third instars. The development time of the overall immature stage decreased from 78.33 days at 15°C to 21.07 days at 30°C, and then increased to 24.33 days at 33°C. The common linear model and the Ikemoto–Takai model were used to estimate the thermal constant (K) and the developmental zero (T₀). The values of T₀ and K for the overall immature stages were 10.50°C and 418.83 degree‐days, and 9.71°C and 451.68 degree‐days by the common model and the Ikemoto–Takai model, respectively. The upper temperature thresholds (T_max) and the optimal temperatures (T_opt) of the egg, the first–third instars and the overall immature stages were estimated by the three nonlinear models. The ranges of T_opt estimated were from 30.33°C to 32.46°C in the overall immature stages and the estimates of T_max of the overall immature stages by the Briere‐1 and the Briere‐2 models were 37.18°C and 33.00°C, respectively. The method to predict the developmental period of L. argyrognomon using the nonlinear models was discussed based on the data of the average temperature per hour.     

The influence of housefly Musca domestica embryo age on viability in water and at low temperatures

The sensitivity of housefly Musca domestica L. (Diptera: Muscidae) embryos to storage at low temperatures (5 and 10 °C on moist sponges in Petri dishes) and in water at 26 °C was investigated to develop suitable protocols for the storage and transport of housefly eggs. The youngest embryos (aged 0–3 h) were the most sensitive to storage at 5 °C, with 45% survival after storage for 24 h. Storage of embryos aged 3–12 h at 5 °C for 24 h had no negative effect; longer storage resulted in significantly decreased larval survival (30–34% after 48–72 h, compared with 61% in the control group) and reduced hatching rates (83% after 72 h storage). No negative effects were observed when embryos aged 0–9 h were stored at 10 °C for 24 h, but this temperature did not completely inhibit development and eggs began to hatch if stored for longer than 24 h. All age groups of embryos showed high mortality after storage in water at 26 °C for 24 h, with the youngest embryos being least resistant to submersion.     

Thermotolerance of brown trout,Salmo trutta,gametes and embryos to increased water temperatures

The present study investigated the effect of increased water temperature on sperm motility when activated in water, on egg water hardening, on the fertilization process and on embryonic development in brown trout, Salmo trutta. Brown trout gametes had a broad temperature optimum ranging from 3 to 15°C. In this temperature range the processes of egg water hardening and fertilization were unaffected. Motility duration was also not affected. The percentages of initial sperm motility and swimming velocity were lower at 9–15°C than at 3–7°C, while the percentage of locally motile spermatozoa was higher. Exposure of brown trout embryos to ≥11°C resulted in reduced percentages of hatched larvae and in increased percentages of malformed larvae. More advanced ontogenetic stages (stages ≥9 according to Ballard [1973]) showed higher tolerance to increased temperature than did less advanced stages (stages <9) when the percentage of eyed stage embryos was used as the evaluation end point. However, when the percentages of hatched larvae and normal shaped larvae were used as evaluation end points, no differences in thermotolerance could be found between the different otogenetic stages.     

Cold tolerance of the coconut hispine beetle, <Emphasis Type="Italic">Brontispa longissima</Emphasis> (Coleoptera: Chrysomelidae) in Japan

The coconut hispine beetle, Brontispa longissima (Gestro), supposedly originated from Papua New Guinea and Indonesia but has recently invaded Southeast and East Asian countries where it has been causing serious damage to Cocos nucifera L. This insect also occurs on the Southwest Islands off Kyushu Island in Japan. To evaluate the potential northward range expansion of this insect in Japan, we investigated its cold tolerance at 0, 5, and 10 °C (egg, larva, pupa, and adult), 13 °C (adult), and 15 °C (egg and hatched larva). At 15 °C, few eggs hatched, and the larvae that hatched died within a few days of hatching. At 13 °C, Ltime₉₅ was estimated to be 23 days for adults, with the most cold-tolerant developmental stage at 10 °C. At all developmental stages, Ltime₉₅ of B. longissima was estimated to be 19 days at 10 °C, 8 days at 5 °C, and 5 days at 0 °C, suggesting the cold tolerance of this beetle is very low. Considering average daily temperatures, it is unlikely that B. longissima can establish itself north of Amami-Oshima Island, located in the far south off the main island of Japan.     

Temperature‐dependent development of the double‐spined spruce bark beetle Ips duplicatus (Sahlberg, 1836) (Coleoptera; Curculionidae)

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Light/Dark Cycle and Temperature-Their Impact on Phosphate-Limited Growth of Oscillatoria redekei VAN GOOR in Semicontinuous Culture

Phosphate-limited growth of Oscillatoria redekei in semicontinuous culture has been studied under conditions of continuous illumination at 20 °C as well as in a 12/12 hours light-dark cycle at temperatures between 5 °C and 20 °C. The subsistence quota (q₀) amounted to 0.052 μmol mm⁻³ under all conditions, when the phosphate quota was expressed on the basis of cell volume. The interaction between temperature and phosphate quota and its impact on growth rate are described by the following model: Parameter values are t_opt=24.5 °C, t_min=0.95 °C, μ_max =0.873 d⁻¹. The maximum phosphate quota was found to depend on temperature and to increase along with declining temperature.     

Effect of temperature on the life history and demographic parameters of Spalgis epius (Lepidoptera: Lycaenidae), a candidate biological control agent of mealybugs (Hemiptera: Pseudococcidae)

Many species of mealybugs (Hemiptera: Pseudococcidae) are serious pests of economically important crops worldwide. We evaluated the influence of constant temperatures: 14, 16, 18, 20, 22, 24, 26, 28, 30, 32 and 34°C on the life history and demographic parameters of Spalgis epius (Lepidoptera: Lycaenidae), a candidate biological control agent of various species of mealybugs. No eggs completed their development at 14 and 34°C. Egg-to-adult developmental time significantly decreased from 89.9 days at 16°C to 20.4 days at 32°C. The estimated lower temperature threshold of 10.2°C and 416.6 degree-days were required to complete egg-to-adult development. The mortality of immature stages was maximum at 16 and 32°C and minimum at 28°C. The highest lifetime fecundity was recorded at 28°C and it significantly decreased at 32°C. The longevity of adults was about three times more at 16°C than at 30 and 32°C. The net reproductive rate (R ₀) significantly increased with increased temperatures up to 28°C and significantly decreased at 32°C. The mean generation time (T) significantly decreased with increased temperature up to 30°C, but it significantly increased at 32°C. The intrinsic rate of population increase (r _m ) was highest at 30°C. The finite rate of increase (λ) was significantly greater at 30°C than at other temperatures. These data suggest that S. epius can develop, reproduce and survive in a wide range of temperatures and thus could be regarded a potential biological control agent of mealybugs.     

Embryonic development characteristics and host mussel utilization of flat bitterling <Emphasis Type="Italic">Acheilognathus rhombeus</Emphasis> (Cyprinidae) during winter in Korea

This study aimed to investigate the embryonic development characteristics and host mussel utilization of Acheilognathus rhombeus to determine its adaptations or host utilization for improving survival during winter in the wild; the study was conducted from August 2014 to May 2015. Spawning of A. rhombeus occurred between mid-September and early November, peaking between late September and early October of 2014 when the water temperature was 19–21°C. The embryos of A. rhombeus were first found in early October of 2014 and remained inside the host mussel for 7 months. Development retardation and diapause in embryonic stages (stages C and D) occurred before eye pigmentation and continued until late March of 2015. Subsequently, the embryos resumed development (stage E) when the water temperature increased to about 10 °C. The positions during the development of A. rhombeus embryos in the mussels were mainly present in the farthest suprabranchial cavity and not in the water tube. The embryos were frequently found in the two inner demibranches of the four gills of the mussels regardless of their sex. We assume that embryonic diapause and use of suprabranchial cavity and inner demibranches of the gills of the mussels by A. rhombeus might be the optimal adaptation to maintain high embryonic survival in low water temperature during winter and to avoid interspecific competition.