Expression of phenotypes in a temperature-sensitive allele of the apterous mutation in Drosophila melanogaster

A temperature-sensitive allele of the apterous (ap) locus of Drosophila melanogaster has been used to examine the phenotypes produced by this mutation, which include wing, mesonotal, and haltere deficiencies, precocious adult death, and nonvitellogenic oocyte development. When raised at 15°C, homozygous ap^ts78j adults have nearly wild-type wing morphology except for patches of missing triple-row bristles and posterior wing margin deficiencies. With the exception of two missing bristles, the dorsal mesonotum and the haltere appear as wild-type. Increasing deficiency of structures derived from the wing and haltere imaginal discs results from increasing culture temperature, and at 29°C, the wing blade, many dorsal mesonotal bristles, and the haltere are absent. The temperature-sensitive period in development for these deficient phenotypes extends from late-second to mid-third instar. Despite extensive deficiencies seen after ap^ts78j larvae are heat-pulsed at 29°C, no duplication of the notal structures is evident, a common response of other mutants having extensive wing deficiencies. When raised at 29 or 25°C, ap^ts78j adults are short-lived, and females show nonvitellogenic oocyte development. At 22°C, however, adults are long-lived, and females are vitellogenic and lay fertile eggs. A sharp temperature-sensitive period for both phenotypes is located during the first 24 hr of pupal development. The application of a juvenile hormone mimic, ZR-515, restored vitellogenesis to ap^ts78j females raised at 25°C but was unable to rescue them from precocious death.     

Studies of l(3)c43hs1 a polyphasic, temperature-sensitive mutant of Drosophila melanogaster with a variety of imaginal disc defects.

The heat-sensitive, lethal mutation l(3)c43^hs1 (3–49.0) produces wide variety of defects in the imaginal discs of Drosophila melanogaster. At permissive temperatures (20°C or lower), homozygotes are viable, but sterile. At 22°C, lethality occurs during the late pupal stage, and at 25°C or higher, lethality occurs during the third larval instar. The imaginal-disc abnormalities observed after exposure to restrictive temperatures include: deficiencies of head structures, duplications and deficiencies of the antenna, a homeotic transformation of the arista to tarsus, duplications and deficiencies of wing and haltere structures, differentiation of amorphous cuticular material in the wing blade, an increase in the number of sex-comb teeth, and disruption of the normal segmentation of the tarsus. Exposure to 27°C for 24 hr at different times in the life cycle revealed that each of these defects has a characteristic temperature-sensitive period (TSP) during the larval stages. Injection of wing discs before and after their TSP showed that the mutation is expressed autonomously. These results are discussed in relation to the role that the l(3)c43⁺ gene plays in the development of imaginal discs.     

Crowding leads to higher incidence of brachypterous females in the tobacco thrips,Frankliniella fusca (Hinds) (Thysanoptera: Thripidae)

The effects of larval density on the wing form determination of female tobacco thrips, Frankliniella fusca, were investigated by rearing thrips on leaf disks at 27.5 °C. The developmental period, head width, body length, and forewing length of individuals in each wing morph were determined to assess the relationships among larval density, growth, and wing form. Data showed that higher rearing densities increased the production of female F. fusca brachypters. There was no consistent difference in the mean developmental periods between the two wing morphs or among all 5 density treatments. The body length of females tended to decrease with increasing rearing density, but there was no significant difference in body size between the two wing morphs when they were reared under the same density level.     

A reversible temperature-induced developmental arrest in Drosophila.

Temperatures between 35.5 and 38°C cause a reversible arrest of imaginal development of wildtype and temperature-sensitive Drosophila melanogaster. A temperature-sensitive mutant, shibire-temperature sensitive 1, which develops abnormally when exposed to 29°C heat pulses during various sensitive periods, fails to produce its ususal mutant phenotypes when exposed to heat pulses of 35–38°C during the same sensitive periods. The results indicate that developmental progress is required for the reversible temperature-sensitive cellular effect of shibire to cause a permanent developmental lesion.     

Effect of larval rearing temperature on adult female morphology of Anopheles (Nyssorhynchus) albimanus (Diptera: Culicidae)

Summary

Time to pupation, percent survival to pupation, and percent adult emergence of Anopheles albimanus Wiedemann decreased at higher larval rearing temperature. Mosquitoes reared at 30°C experienced higher mortality during the pupal stage than did mosquitoes reared at 22°C. Analysis of variance revealed that wing length and costal wing spot patterns of adult female A. albimanus were affected by larval rearing temperature. Female A. albimanus reared at 22°C had longer wings, and larger basal pale + prehumeral pale, prehumeral dark, and humeral pale costal wing spots than did female siblings reared at 30°C. Female A. albimanus reared at 30°C had larger subcostal pale spots than did female siblings reared at 22°C. Analyses of 2x2 contingency tables indicated that sex ratio was independent of larval rearing temperature, whereas survival to the adult stage and coalescence of wing spots were not independent of rearing temperature. The need to examine stability of morphological characters under differing environmental conditions is discussed.     

Environmental factors controlling seasonal morph determination in the small copper butterfly, Lycaena phlaeas daimio Seitz.

Environmental factors controlling seasonal morph determination and extension of the larval stages in Lycaena phlaeas daimio were studied in field observations and laboratory experiments, using criteria based on the numbers of red scales in the wing spots. Photoperiod and temperature conditions applied during the larval period and a low-temperature (5°C) introduced in pupal period were expected to be factors affecting the seasonal morph determination: the effects were confirmed by laboratory experiments. Furthermore, the length of the larval period extended by exposure to short days at 20°C, but not at 25°C, were found to show a clear correlation with the spring morph determination, but the correlation coefficient was negative in marked contrast to the situation in Polygonia and Papilio.     

Effect of temperature on life-history traits and mating calls of a field cricket,Acanthogryllus asiaticus

Ectotherms are sensitive to changes in ambient temperature that impact their physiology and development. To compensate for the effects of variation in temperature, ectotherms exhibit short or long-term physiological plasticity. An extensive body of literature exists towards understanding these effects and the solutions ectotherms have evolved. However, to what extent rearing temperature during early life stages impacts the behaviour expressed in adulthood is less clearly understood. In the present study, we aimed to examine the effects of developmental temperature on life-history traits and mating call features in a tropical field cricket, Acanthogryllus asiaticus. We raised A. asiaticus at two different developmental conditions: 25 °C and 30 °C. We found developmental time and adult lifespan of individuals reared at 30 °C to be shorter than those reared at 25 °C. Increased developmental temperature influenced various body size parameters differentially. Males raised at 30 °C were found to be larger and heavier than those raised at 25 °C, making A. asiaticus an exception to the temperature-size rule. We found a significant effect of change in immediate ambient temperature on different call features of both field-caught and lab-bred individuals. Developmental temperature also affected mating call features wherein individuals raised at higher temperature produced faster calls with a higher peak frequency compared to those raised at lower temperature. In addition, an interactive effect of both developmental and immediate temperature was found on mating call features. Our study highlights the importance of understanding how environmental temperature shapes life-history and sexual communication in crickets.     

Development of Geocoris varius and G. proteus (Hemiptera: Geocoridae) provided with Ephestia kuehniella (Lepidoptera: Pyralidae) eggs

We studied the development of Geocoris varius (Uhler) and Geocoris proteus Distant reared on Ephestia kuehniella Zeller eggs at 20, 24, 26, 30, 33, or 36?°C. The lower developmental thresholds (T ₀) and the thermal constants (K) of eggs and nymphs of G. varius were 13.3?°C, 151.1 degree-days and 13.4?°C, 433.0 degree-days, respectively; those of G. proteus were 16.1?°C, 98.3 degree-days and 16.9?°C, 226.9 degree-days, respectively. The hatch rate of G. varius eggs was significantly lower at 33?°C than at ??30?°C, and no eggs hatched at 36?°C. That of G. proteus was lowest at 20?°C and did not decline significantly at 36?°C. The survival rate throughout the nymphal period increased with temperature up to 30?°C in G. varius, and it was lowest at 20?°C in G. proteus. Thus, the optimal rearing temperatures for immature stages appear to be about 24?C30?°C for G. varius and 26?C33?°C for G. proteus. It might be possible to improve the efficiency of their mass production by controlling the rearing temperature in the above ranges. This would also make the developmental stages of nymphs more uniform and so prevent cannibalism in mass rearing.     

Divergence of water balance mechanisms in two sibling species (Drosophila simulans and D. melanogaster): effects of growth temperatures

Drosophila simulans is more abundant under colder and drier montane habitats in the western Himalayas as compared to its sibling D. melanogaster but the mechanistic bases of such climatic adaptations are largely unknown. Previous studies have described D. simulans as a desiccation sensitive species which is inconsistent with its occurrence in temperate regions. We tested the hypothesis whether developmental plasticity of cuticular traits confers adaptive changes in water balance-related traits in the sibling species D. simulans and D. melanogaster. Our results are interesting in several respects. First, D. simulans grown at 15 °C possesses a high level of desiccation resistance in larvae (~39 h) and in adults (~86 h) whereas the corresponding values are quite low at 25 °C (larvae ~7 h; adults ~13 h). Interestingly, cuticular lipid mass was threefold higher in D. simulans grown at 15 °C as compared with 25 °C while there was no change in cuticular lipid mass in D. melanogaster. Second, developmental plasticity of body melanisation was evident in both species. Drosophila simulans showed higher melanisation at 15 °C as compared with D. melanogaster while the reverse trend was observed at 25 °C. Third, changes in water balance-related traits (bulk water, hemolymph and dehydration tolerance) showed superiority of D. simulans at 15 °C but of D. melanogaster at 25 °C growth temperature. Rate of carbohydrate utilization under desiccation stress did not differ at 15 °C in both the species. Fourth, effects of developmental plasticity on cuticular traits correspond with changes in the cuticular water loss i.e. water loss rates were higher at 25 °C as compared with 15 °C. Thus, D. simulans grown under cooler temperature was more desiccation tolerant than D. melanogaster. Finally, desiccation acclimation capacity of larvae and adults is higher for D. simulans reared at 15 °C but quite low at 25 °C. Thus, D. simulans and D. melanogaster have evolved different strategies of water conservation consistent with their adaptations to dry and wet habitats in the western Himalayas. Our results suggest that D. simulans from lowland localities seems vulnerable due to limited acclimation potential in the context of global climatic change in the western Himalayas. Finally, this is the first report on higher desiccation resistance of D. simulans due to developmental plasticity of both the cuticular traits (body melanisation and epicuticular lipid mass) when grown at 15 °C, which is consistent with its abundance in temperate regions.     

Development of Sarcophaga dux (diptera: Sarcophagidae) at constant temperatures and differential gene expression for age estimation of the pupae

Sarcophaga dux (Diptera: Sarcophagidae) is a necrophagous flesh fly species with potential forensic value for estimating minimum postmortem interval (PMI_min). The basic developmental data and precise age estimates of the pupae are significant for PMI_min estimation in forensic investigations. In the present study, we investigated the development data of that species at seven constant temperatures varying from 16 °C to 34 °C, including body length changes of the larve, developmental duration and accumulated degree hours of the preadults. Several reference genes for relative quantification of the differentially expressed genes (DEGs) were firstly selected and evaluated in the pupae of different ages under different temperatures. The DEGs of the insects during the pupal period at different constant temperatures (34, 25 and 16 °C) were further analyzed for more precise age estimation. The results showed that the developmental durations of the preadults at 16, 19, 22, 25, 28, 31 and 34 °C were 1478.6 ± 18.3 h, 726.1 ± 15.8 h, 538.5 ± 0.9 h, 394.1 ± 9.5 h, 375.6 ± 10.8 h, 284.1 ± 7.3 h, and 252.5 ± 6.1 h, respectively. The developmental threshold temperature the flies was 12.27 ± 0.35 °C, and the thermal summation constant was 5341.71 ± 249.29° hours. The most reliable reference genes during the pupal period at different temperatures were found: GST1 and 18S rRNA for the 34 °C group, GST1 and RPL49 for 25 °C, and 18S rRNA and 28S rRNA for 16 °C. The four differential expression genes (Hsp60, A-alpha, ARP, and RPL8) have the potential to be used for more precise age estimation of pupal S. dux. This work provides important basic developmental data and a more precise age estimation method for pupal S. dux, and improves the value of this species for PMI_min estimation in forensic investigations.     

Temperature-dependent development of Lista haraldusalis (Walker) (Lepidoptera: Pyralidae) on Platycarya strobilacea

The effect of constant temperatures on development and survival of Lista haraldusalis (Walker) (Lepidoptera: Pyralidae), a newly reported insect species used to produce insect tea in Guizhou province (China), was studied in laboratory conditions at seven temperatures (19 °C, 22 °C, 25 °C, 28 °C, 31 °C, 34 °C, and 37 °C) on Platycarya strobilacea. Increasing the temperature from 19 °C to 31 °C led to a significant decrease in the developmental time from egg to adult emergence, and then the total developmental time increased at 34 °C. Egg incubation was the stage where L. haraldusalis experienced the highest mortality at all temperatures. The survival of L. haraldusalis was significantly higher at 25 °C and 28 °C, whereas none of the eggs hatched at 37 °C. Common and Ikemoto linear models were used to describe the relationship between the temperature and the developmental rate for each immature stage of L. haraldusalis. The estimated values of the lower temperature threshold and thermal constant of the total immature stages using Common and Ikemoto linear models were 11.34 °C and 11.20 °C, and 939.85 and 950.41 degree-days, respectively. Seven nonlinear models were used to fit the experimental data to estimate the developmental rate of L. haraldusalis. Based on the biological significance for model evaluation, Ikemoto linear, Logan-6, and SSI were the best models that fitted each immature stage of L. haraldusalis and they were used to estimate the temperature thresholds. These thermal requirements and temperature thresholds are crucial for facilitating the development of factory-based mass rearing of L. haraldusalis.     

Wheat quality related differential expressions of albumins and globulins revealed by two-dimensional difference gel electrophoresis (2-D DIGE)

Comparative proteomics analysis offers a new approach to identify differential proteins among different wheat genotypes and developmental stages. In this study, the non-prolamin expression profiles during grain development of two common or bread wheat cultivars (Triticum aestivum L.), Jing 411 and Sunstate, with different quality properties were analyzed using two-dimensional difference gel electrophoresis (2-D DIGE). Five grain developmental stages during the post-anthesis period were sampled corresponding to the cumulative averages of daily temperatures (°C: 156 °C, 250 °C, 354 °C, 447 °C and 749.5 °C). More than 400 differential protein spots detected at one or more of the developmental stages of the two cultivars were monitored, among which 230 proteins were identified by MS. Of the identified proteins, more than 85% were enzymes possessing different physiological functions. A total of 36 differential proteins were characterized between the two varieties, which are likely to be related to wheat quality attributes. About one quarter of the proteins identified expressed in multiple spots with different pIs and molecular masses, implying certain post-translational modifications (PTMs) of proteins such as phosphorylations and glycosylations. The results provide new insights into biochemical mechanisms for grain development and quality.     

The genetics of phenotypic plasticity. III. Genetic correlations and fluctuating asymmetries

We examined the relationship of three aspects of development, phenotypic plasticity, genetic correlations among traits, and developmental noise, for thorax length, wing length, and number of sternopleural bristles in Drosophila melanogaster. We used 14 lines which had previously been selected on either thorax length or plasticity of thorax length in response to temperature. A half-sib mating design was used and offspring were raised at 19° C or 25° C. We found that genetic correlations were stable across temperatures despite the large levels of plasticity of these traits. Plasticities were correlated among developmentally related traits, thorax and wing length, but not among unrelated traits, lengths and bristle counts. Amount of developmental noise, measured as fluctuating asymmetry and within-environmental variation, was positively correlated with amount of plasticity only for some traits, thorax length and bristle number, and only at one temperature, 25° C.     

Occurrence model of first instars of Ricania shantungensis (Hemiptera: Ricaniidae)

An invasive planthopper, Ricania shantungensis, is an important pest in agriculture and forestry in Korea. Best target stage for insecticide application is known to be newly hatched first instar. Thus, the objective of the present study was to predict the occurrence of first instars of R. shantungensis. Effects of temperature on development and survival of R. shantungensis eggs were examined at seven constant temperatures (12.4, 16.4, 20.4, 24.8, 28.3, 32.4, and 36.9 °C). Development and survival of R. shantungensis eggs were quantitatively described by applying empirical models as a function of temperature over a wide thermal range. Lower developmental threshold, thermal constant, optimal developmental temperature, and upper developmental threshold were estimated to be 12.1 °C, 202 DD, 31 °C, and 36.9 °C, respectively. Survivorship was the highest at 23.3 °C. The models well predicted timing of field occurrences at three sites (Buyeo, Gwangyang, and Habcheon) in Korea. Therefore, results of this study would increase the prediction accuracy of R. shantungensis occurrence and management efficiency of R. shantungensis.     

WITHIN- AND BETWEEN-GENERATION EFFECTS OF TEMPERATURE ON THE MORPHOLOGY AND PHYSIOLOGY OF DROSOPHILA MELANOGASTER

We investigated the effects of developmental and parental temperatures on several physiological and morphological traits of adult Drosophila melanogaster. Flies for the parental generation were raised at either low or moderate temperature (18°C or 25°C) and then mated in the four possible sex-by-parental temperature crosses. Their offspring were raised at either 18°C or 25°C and then scored as adults for morphological (dry body mass, wing size, and abdominal melanization [females only]), physiological (knock-down temperature, and thermal dependence of walking speed), and life history (egg size) traits. The experiment was replicated, and the factorial design allows us to determine whether and how paternal, maternal, and developmental temperatures (as well as offspring sex) influence the various traits. Sex and developmental temperature had major effects on all traits. Females had larger bodies and wings, higher knock-down temperatures, and slower speeds (but similar shaped performance curves) than males. Development at 25°C (versus at 18°C) increased knock-down temperature, increased maximal speed and thermal performance breadth, decreased the optimal temperature for walking, decreased body mass and wing size, reduced abdominal melanization, and reduced egg size. Parental temperatures influenced a few traits, but the effects were generally small relative to those of sex or developmental temperature. Flies whose mother had been raised at 25°C (versus at 18°C) had slightly higher knock-down temperature and smaller body mass. Flies whose father had been raised at 25°C had relatively longer wings. The effects of paternal, maternal, and developmental temperatures sometimes differed in direction. The existence of significant within- and between-generation effects suggests that comparative studies need to standardize thermal environments for at least two generations, that attempts to estimate “field” heritabilities may be unreliable for some traits, and that predictions of short-term evolutionary responses to selection will be difficult.     

Evolutionary changes of nonlinear reaction norms according to thermal adaptation: a comparison of two Drosophila species

While the adaptive significance of discontinuous reaction norms is generally accepted, the evolutionary interpretation of continuous response curves remains speculative, and the occurrence of internal constraints is often suggested as an explanation of experimental observations. In Drosophila melanogaster, various morphometrical traits exhibit convex reaction norms to growth temperature, with a maximum value within the developmental thermal range. We compared a cold-adapted species (D. subobscura) with a mid thermal range at 16 °C, to the warm-adapted D. melanogaster (mid thermal range at 22 °C) for three different morphometrical traits: wing and thorax length in both sexes and ovariole number in females. Maximum value temperatures were ordered in the same way for the three traits in both species: ovariole number > thorax length > wing length. Significant differences were also observed between the two species for the curvature parameter of the quadratic adjustment. The major observation was a significant lateral shift in the reaction norms: maximum values were observed at much lower temperatures in the cold-adapted species than in the warm-adapted one. The parallelism between mid thermal range variation and the position of the maximum value strongly suggests an adaptive displacement of the response curves. Natural selection may thus act not only on trait mean values but also on phenotypic plasticity and on the shape of reaction norms.     

EVOLUTION AND DEVELOPMENT OF BODY SIZE AND CELL SIZE IN DROSOPHILA MELANOGASTER IN RESPONSE TO TEMPERATURE

We examined the evolutionary and developmental responses of body size to temperature in Drosophila melanogaster, using replicated lines of flies that had been allowed to evolve for 5 yr at 25°C or at 16.5°C. Development and evolution at the lower temperature both resulted in higher thorax length and wing area. The evolutionary effect of temperature on wing area was entirely a consequence of an increase in cell area. The developmental response was mainly attributable to an increase in cell area, with a small effect on cell number in males. Given its similarity to the evolutionary response, the increase in body size and cell size resulting from development at low temperature may be a case of adaptive phenotypic plasticity. The pattern of plasticity did not evolve in response to temperature for any of the traits. The selective advantage of the evolutionary and developmental responses to temperature is obscure and remains a major challenge for future work.     

Genetic variation and plasticity of thorax length and wing length in Drosophila aldrichi and D. buzzatii

Reaction norms across three temperatures of development were measured for thorax length, wing length and wing length/thorax length ratio for ten isofemale lines from each of two populations of Drosophila aldrichi and D. buzzatii. Means for thorax and wing length in both species were larger at 24 °C than at either 18 °C or 31 °C, with the reduction in size at 18 °C most likely due to a nutritional constraint. Although females were larger than males, the sexes were not different for wing length/thorax length ratio. The plasticity of the traits differed between species and between populations of each species, with genetic variation in plasticity similar for the two species from one locality, but much higher for D. aldrichi from the other. Estimates of heritabilities for D. aldrichi generally were higher at 18 °C and 24 °C than at 31 °C, but for D. buzzatii they were highest at 31 °C, although heritabilities were not significantly different between species at any temperature. Additive genetic variances for D. aldrichi showed trends similar to that for heritability, being highest at 18 °C and decreasing as temperature increased. For D. buzzatii, however, additive genetic variances were lowest at 24 °C. These results are suggestive that genetic variation for body size characters is increased in more stressful environments. Thorax and wing lengths showed significant genetic correlations that were not different between the species, but the genetic correlations between each of these traits and their ratio were significantly different. For D. aldrichi, genetic variation in the wing length/thorax length ratio was due primarily to variation in thorax length, while for D. buzzatii, it was due primarily to variation in wing length. The wing length/thorax length ratio, which is the inverse of wing loading, decreased linearly as temperature increased, and it is suggested that this ratio may be of greater adaptive significance than either of its components.     

Temperature dependent development and temperature thresholds of Rhyncaphytoptus ficifoliae Keifer (Diptilomiopidae)

The effects of temperature on developmental rate of Rhyncaphytoptus ficifoliae Keifer (Diptilomiopidae) were determined at six constant temperatures (17, 20, 25, 30, 33 and 36 °C) on fig leaves. The total developmental time of females decreased as temperature increased from 17 (21.62 days) to 33 °C (6.02 days), and then increased at 36 °C (6.47 days). Using the ordinary and Ikemoto and Takai (2000) linear models the estimated lower temperature thresholds (T_min) for total developmental time of females were 10.78 and 10.37 °C and the constant temperatures (k) were 140.25 and 144.78°-days (DD), respectively. Data also were fitted to SSI nonlinear temperature-dependent model. The estimated T_L, intrinsic optimum temperature (T_Ф) and T_h for total immature stages of females by SSI model were 11.11, 23.72 and 37.98 °C, respectively. With use of the obtained data from rearing R. ficifoliae under constant temperatures in laboratory and temperature data in Khorramabad region in 2017, the real developmental rate of this mite in natural conditions was described. The highest (100%) and lowest values (51.67%) of survival rate for immature stages were found at 25 and 36 °C, respectively. The presented information could be used to predict the population dynamics of main pest R. ficifoliae for an effective management.