The relationship between total sialic acid levels and antioxidant status in the tadpoles of Bufo viridis and Rana ridibunda ridibunda

Total sialic acid levels (TSA), antioxidant enzymes activities such as superoxide dismutase (SOD), catalase (CAT) and lipid peroxidation (LPO) levels were investigated during the developmental period in tadpoles of the predominantly terrestrial amphibian B. viridis and the predominantly aquatic amphibian R. r. ridibunda. Maximum TSA levels were observed in B. viridis and R. r. ridibunda at the fifth and third week of their development, respectively. SOD and CAT activity variations during development in B. viridis were higher than in R. r. ridibunda. Although SOD activity in B. viridis was higher than R. r. ridibunda at the eighth week, SOD activity increased 19.2-fold in R. r. ridibunda and 10.4-fold in B. viridis between the first and eighth week. CAT activity in R. r. ridibunda did not significantly change (p>0.001) until the fifth week then increased, whereas in B. viridis CAT increased after the third week. In contrast to the rise in the antioxidant enzyme activities, LPO levels tended to decrease during the developmental period. Levels of LPO showed a similar trend until the third week for both species. The minimum LPO levels in B. viridis and R. r. ridibunda were 23+/-1.2 and 146+/-7.3 nmol MDA g(-1) tissue, at the eighth week, respectively. While decreasing LPO levels correlated with increasing antioxidant enzyme activities, TSA tended to decrease after reaching a maximum point.     

Glutathione redox system,GSH-Px activity and lipid peroxidation (LPO) levels in tadpoles of R.r.ridibunda and B.viridis

Total glutathione (t-GSH), reduced glutathione (GSH), glutathione disulphide (GSSG) levels, t-GSH/GSSG ratio, glutathione peroxidase (GSH-Px) activity and lipid peroxidation (LPO) levels were investigated during the development period of a predominantly aquatic amphibian R.r.ridibunda and a predominantly terrestrial amphibian B. viridis. While t-GSH and GSH showed a similar trend, GSSG concentration increased significantly (p<0.05) during the larval stages in R.r.ridibunda larvae. In contrast to R.r.ridibunda larvae, there was no significant (p>0.05) change between 1 and 5 weeks in the t-GSH and GSH concentrations of B. viridis. t-GSH and GSH concentrations of B. viridis larvae became sharply elevated after the fifth week, GSSG levels increased 3.25-fold during the metamorphosis. The t-GSH/GSSG ratio fluctuated and the lowest t-GSH/GSSG ratios were observed at the third week for both species. GSH-Px activities for both species increased significantly (p<0.05) during the growing period. The highest GSH-Px activities in R.r.ridibunda and B.viridis were observed at the eighth week and they were 3.45 +/- 0.17 and 4.1 +/- 0.21 IU mg(-1), respectively. The membrane LPO levels in the R.r.ridibunda and B. viridis tadpoles significantly (p<0.001) decreased from 206 +/- 10.3 to 146 +/- 7.3 and from 198 +/- 9.9 to 23 +/- 1.15 nmol MDA g(-1) w.w., respectively.     

Urea tolerance and osmoregulation in Bufo viridis and Rana ridibunda

1. The tolerance and adaptation to urea solutions by terrestrial green toads (Bufo viridis) and semi-aquatic frogs (Rana Ridibunda) were studied. 2. the green toad showed tolerance to urea solution of 800 mM and the frogs showed tolerance only to about 400 mM urea solution. 3. The plasma concentrations of both species was hyperosmotic to the external medium in all the different urea solutions. 4. Blood osmolality, urea, Na+ and Cl- concentrations of B. viridis were always higher than in R. ridibunda. 5. The urea concentration in muscle of R. ridibunda was higher than the urea concentration in muscle of B. viridis. 6. The muscle tissue weight loss of B. viridis was significantly lower than R. ridibunda.     

Evolutionary history of the hybridogenetic hybrid frog Rana esculenta as deduced from mtDNA analyses [published erratum appears in Mol Biol Evol 1986 Sep;3(5):463]

mtDNA of the hybridogenetic hybrid frog Rana esculenta from Switzerland, Austria, and Poland was compared to mtDNA of the parental species R. ridibunda and R. lessonae using electrophoretic analysis of restriction enzyme fragments. Two mtDNA phenotypes, with 3.4% sequence divergence, are present in R. lessonae: type C is found in Poland, and type D is found in Switzerland. Rana ridibunda from Poland has either of two mtDNA phenotypes: type A is the typical ridibunda mtDNA, and type B is a lessonae mitochondrial genome, introgressed into R. ridibunda, that differs from type C mtDNA of R. lessonae by only 0.3%. Each of the three lessonae genomes differs from A, the typical ridibunda mtDNA, by approximately 8%. All four types of mtDNA (A and B of R. ridibunda, C and D of R. lessonae) are found in R. esculenta. Of 62 R. esculenta from Poland, 58 had type C, three had type A, and one had type B mtDNA. All nine R. esculenta from Switzerland had type D mtDNA. All three R. esculenta from Austria, from a population in which males of R. esculenta are rare, had ridibunda mtDNA, two having type B and one having type A. Both field observations and studies of mating preference indicate that the primary hybridizations that produce R. esculenta are between R. ridibunda females and R. lessonae males; thereafter, R. esculenta lineages are usually maintained by matings of R. esculenta females with R. lessonae males. The presence of ridibunda mtDNA in the three R. esculenta sampled from Austria, its occasional presence in R. esculenta populations in Poland, and its absence from R. esculenta in Switzerland support both the direction of the original hybridization and the rarity of formation of new R. esculenta lineages. The preponderance of R. esculenta individuals with lessonae mtDNA in our samples from central Europe suggests that most lineages have gone through at least one mating between an R. lessonae female and an R. esculenta male. This reveals a greater reproductive role for R. esculenta males than their partial sterility and infrequent matings would suggest.      

Triggering of cryoprotectant synthesis in the woolly bear caterpillar (Pyrrharctia isabella Lepidoptera: Arctiidae)

Isabella tiger moths (Pyrrharctia isabella) overwinter as caterpillars (i.e., woolly bears) that can survive freezing at moderate subzero temperatures. We observed an increase in hemolymph osmolality for field-collected woolly bears during October (325 +/- 47 to 445 +/- 27 mOsmol/liter) and tested the influence of temperature and moisture levels on cryoprotectant production. Laboratory acclimation was done at 5 degrees C in moist conditions and at 25 degrees C acclimation in both dry and moist conditions. Body water contents were diminished by dehydration at 25 degrees C for 4 days (57 +/- 4%). Caterpillars collected in early October did not alter their hemolymph osmolality during cold acclimation, but caterpillars increased by 45% (to 647 +/- 90 mOsmol/liter) after 4 days at 5 degrees C following their collection in late October. Hemolymph composition was markedly changed in caterpillars experiencing dehydration at 25 degrees C (1042 +/- 200 mOsmol/liter; 507 +/- 225 mmol glycerol/liter), whereas caterpillars showed no change in their hemolymph composition when kept moist at 25 degrees C. Our experiments reveal that both dehydration and cold acclimation rapidly induce cryoprotectant synthesis in P. isabella caterpillars. J. Exp. Zool. 286:367-371, 2000.     

Widespread unidirectional transfer of mitochondrial DNA: a case in western Palaearctic water frogs

Interspecies transfer of mitochondrial (mt) DNA is a common phenomenon in plants, invertebrates and vertebrates, normally linked with hybridization of closely related species in zones of sympatry or parapatry. In central Europe, in an area north of 48 degrees N latitude and between 8 degrees and 22 degrees E longitude, western Palaearctic water frogs show massive unidirectional introgression of mtDNA: 33.7% of 407 Rana ridibunda possessed mtDNA specific for Rana lessonae. By contrast, no R. lessonae with R. ridibunda mtDNA was observed. That R. ridibunda with introgressed mitochondrial genomes were found exclusively within the range of the hybrid Rana esculenta and that most hybrids had lessonae mtDNA (90.4% of 335 individuals investigated) is evidence that R. esculenta serves as a vehicle for transfer of lessonae mtDNA into R. ridibunda. Such introgression has occurred several times independently. The abundance and wide distribution of individuals with introgressed mitochondrial genomes show that R. lessonae mt genomes work successfully in a R. ridibunda chromosomal background despite their high sequence divergence from R. ridibunda mtDNAs (14.2-15.2% in the ND2/ND3 genes). Greater effectiveness of enzymes encoded by R. lessonae mtDNA may be advantageous to individuals of R. ridibunda and probably R. esculenta in the northern parts of their ranges.     

Physiological characterization of Dunaliella sp. (Chlorophyta, Volvocales) from Yucatan, Mexico

Physiological responses of Dunaliella salina and Dunaliella viridis, isolated from solar saltworks on the Yucatan Peninsula, were studied. Optimal growth temperature for D. salina was 22 degrees C (3.06 x 10(6) cells mL(-1)) and 26 degrees C for D. viridis (4.04 x 10(6)cells mL(-1)). Total carotenoid content in D. salina increased with temperature to a maximum of 35.14 pg cell(-1) at 38 degrees C. Dunaliella salina alpha-carotene and beta-carotene content was 0.083+/-0.003 and 0.598+/-0.020 mg 100g dry wt(-1) respectively, whereas lower values were found in D. viridis cultured under same experimental conditions (0.018+/-0.002 and 0.136+/-0.012 mg 100g dry wt(-1) respectively). The highest specific growth rate in D. salina was obtained at 10% NaCl (0.28 d(-1)), while its cell volume increased from 524 to 2066.93 microm(3) when cultured from 10% to 35% NaCl. Maximum photosynthetic rates were attained when increasing from optimal growing temperature to 30 degrees C for D. viridis (108 n mol O(2)microg chl alpha h(-1)) and D. salina (139 n mol O(2)microg chl alpha h(-1)). Photosynthetic responses to temperature variations indicated physiological adjustments in both species, with higher acclimation in D. salina. Evaluation of physiological attributes of these species will be used for to carry out mass cultivation.     

Effects of temperature on metabolism,ventilation, and oxygen extraction in the southern brown bandicoot Isoodon obesulus (Marsupialia: Peramelidae)

The effects of ambient temperatures (T(a)) from 10 degrees to 35 degrees C on metabolism, ventilation, and oxygen extraction were examined for the southern brown bandicoot (Isoodon obesulus). Oxygen consumption (VO2) followed the pattern typical for endotherms, decreasing with increasing T(a) from 10 degrees to 25 degrees C. It did not significantly change between Ta=25 degrees and 35 degrees C (the thermoneutral zone). VO2 was approximately 2.4 times higher at Ta=10 degrees C (0.967 mL O(2) g(-1) h(-1)) compared with basal (0.410 mL O(2) g(-1) h(-1)) at Ta=30 degrees C. While the metabolic rates of the bandicoots were basal at Ta=30 degrees C, respiratory frequency (f(R)) was 24.6 breaths min(-1), tidal volume (V(T)) was 7.79 mL, minute volume (V(I)) was 191.3 mL min(-1), and oxygen extraction efficiency (EO2) was 26.8%. Increased VO2 at Ta< or =25 degrees C was associated with a large increase in V(I) due to increases in V(T) and f(R). A greater proportion of the change was due to the increase in tidal volume. EO2 was constant at approximately 26% for all T(a) up to and including 30 degrees C. At Ta=35 degrees C, EO2 decreased to 17.7%, f(R) increased to 35.6 breaths min(-1), and V(T) decreased to 7.22 mL. The metabolic and ventilatory physiology of the southern brown bandicoot are typical of an unspecialized medium-sized marsupial.     

Temperature effect on kinetics of uptake, transfer, and clearance of [14C]noviflumuron in eastern subterranean termites (Isoptera: Rhinotermitidae)

[14C]Noviflumuron uptake, clearance, rate of excretion, and transfer from treated to untreated termite workers were evaluated at 15,19, 23, and 27 degrees C. Feeding units were constructed from plastic containers provisioned with washed sand, distilled water, [14C]noviflumuron-treated feeding discs (0.05 or 0.5% [AI]), and Reticulitermes flavipes (Kollar) workers. Feeding units were held in environmental growth chambers preset at 15, 19, 23, and 27 degrees C. The amount of [14C]noviflumuron present within R. flavipes was measured by scintillation counting and subsequently quantified. Uptake of noviflumuron by R. flavipes workers at 15 degrees C was approximately 2.8 times less than at 19 or 23 degrees C and approximately 4.4 times less than at 27 degrees ighest uptake of [14C]noviflumuron occurred at 27 degrees C and 144 h. Most transfer of [14C]noviflumuron from treated to untreated termite workers occurred between 19 and 27 degrees C. [14C]Noviflumuron had a half-life in R. flavipes workers of approximately 31-45 d, dependent on temperature. A higher amount of [14C]noviflumuron was lost through excretion at > or = 19 degrees C (approximately 15-22%) compared with 15 degrees C (0.27%). Results indicated that increased uptake, transfer, and clearance of noviflumuron by R. flavipes occurred at warmer temperatures (19-27 degrees C), and all of these processes were significantly lower at 15 degrees C.     

Electrical and mechanical effects induced by cold temperatures in the ventricle of isolated Rana ridibunda hearts

A temperature decrease changes the contractility of the amphibian heart, but the underlying mechanisms are not totally understood. The objectives of the present work were to better understand the intrinsic mechanisms supporting contractility changes induced by a rapid temperature decrease in the ventricle of Rana ridibunda, and to investigate how fast they develop. Ventricular mechanical cycles (VMCs) and monophasic action potentials (MAPs) recorded from 15 isolated hearts were measured at 15, 30, 45, 60, 90, 120 and 150 s after the application of Ringer solutions of 20, 10 and 5 degrees C. Treatment with 10 and 5 degrees C Ringer solutions decreased the heart rate, and increased the magnitude of the ventricular contraction and the duration of the contraction and relaxation periods. The electrical changes included prolongation of the MAP depolarization plateau, which also decreased in amplitude as an effect of perfusion with 5 degrees C Ringer solution. In addition, treatment with 5 degrees C Ringer solution increased the latency of contraction. The block of L-type channels totally abolished the depolarization plateau at all perfusion temperatures, but failed to inhibit ventricular contraction. In conclusion, treatment with cold temperatures changes the electrical activity of the ventricular myocardium in R. ridibunda hearts, which results in modified ventricular contractility. Data suggest that in addition to L-type Ca2+ channels, other components that support calcium elevation are present R. ridibunda ventricular cells.     

Thermal and metabolic responsiveness of Japanese quail embryos following periodic exposure to 2,450 MHz microwaves

Two studies were performed to determine if repeated exposure of the avian egg to microwaves can alter metabolism, temperature, and growth rate of embryos. Another aim was to supplement conventional heating with microwave heating and provide an optimal temperature for growth. Japanese quail (Coturnix coturnix japonica) eggs were exposed from day 1 through 15 of incubation (8 h/day) to sham or microwave (2,450 MHz) irradiation. Microwave exposures were at two power densities, 5 or 20 mW/cm2, and at three ambient temperatures (Tas), 30.0, 33.1, or 35.4 degrees C. Specific absorption rates for unincubated and 15-day-old incubated eggs were, respectively, 0.76 and 0.66 W kg-1 mW-1 cm-2 (i.e., 3.8 and 3.3 W/kg at 5 mW/cm2 and 15.2 and 13.2 W/kg at 20 mW/cm2). Eggs were concurrently sham exposed at each of five Tas, ranging from 27.9 to 37.5 degrees C. Tests were conducted during the 16th day of incubation (i.e., 1 day post-treatment), in the absence of microwaves, to determine metabolic rate of embryos and internal and external egg temperatures at different Tas. Repeated exposures to microwaves at 5 and 20 mW/cm2 at the same Ta (30 degrees C) increased wet-embryo mass on the 16th day by an average, respectively, of 9% and 61% when compared with predicted masses for embryos exposed at the same Ta in the absence of microwave radiation. There was no reliable indication, from post-treatment tests and comparisons with control embryos of similar mass, that repeated exposure to microwave radiation resulted in abnormal physiological development. Microwave radiation can be used to increase egg temperature and embryonic growth rate at Tas below normal incubation level without altering basic metabolic and thermal characteristics of the developing bird.     

Positional cloning of the mouse saccharin preference (Sac) locus

Differences in sweetener intake among inbred strains of mice are partially determined by allelic variation of the saccharin preference (Sac) locus. Genetic and physical mapping limited a critical genomic interval containing Sac to a 194 kb DNA fragment. Sequencing and annotation of this region identified a gene (Tas1r3) encoding the third member of the T1R family of putative taste receptors, T1R3. Introgression by serial backcrossing of the 194 kb chromosomal fragment containing the Tas1r3 allele from the high-sweetener-preferring C57BL/6ByJ strain onto the genetic background of the low-sweetener-preferring 129P3/J strain rescued its low-sweetener-preference phenotype. Polymorphisms of Tas1r3 that are likely to have functional significance were identified using analysis of genomic sequences and sweetener-preference phenotypes of genealogically distant mouse strains. Tas1r3 has two common haplotypes, consisting of six single nucleotide polymorphisms: one haplotype was found in mouse strains with elevated sweetener preference and the other in strains relatively indifferent to sweeteners. This study provides compelling evidence that Tas1r3 is equivalent to the Sac locus and that the T1R3 receptor responds to sweeteners.     

羚牛苦味受体3(Tas2R3)基因的克隆及生物信息学分析

Tas2R3是苦味受体基因家族中一个重要的成员,为了进一步了解和研究羚牛(Budorcas taxicolor)苦味受体基因的结构和功能,本研究对羚牛苦味受体3 (Tas2R3)基因进行了克隆和生物信息学分析(GenBank登录号:MG650195)。结果显示,羚牛Tas2R3基因编码区(coding sequence, CDS)序列全长951 bp,共编码316个氨基酸,以亮氨酸含量最高,谷氨酰胺含量最低。其蛋白质等电点为9.68,分子量为51.96 kD。高级结构功能预测显示,二级结构以α-螺旋为主,蛋白质为碱性、稳定的亲水性蛋白,由4个胞外区、7个跨膜区和4个胞内区组成。预测到2种类型共8个糖基化功能位点和4种类型共15个磷酸化功能位点。通过比较Tas2R3基因种间相似性发现,在偶蹄目中具有很高的同源性,羚牛与绵羊(Ovis aries)的相似性最高(0.98),与褐家鼠(Rattus norvegicus)最低(0.52)。用羚牛、绵羊等12个物种的Tas2R3基因CDS序列构建的NJ树与ME树结构一致,表明Tas2R3基因适合用于构建不同物种间的系统进化树。     

Thermoregulatory and metabolic changes during fever in young and old rats

We injected old and young rats with lipopolysaccharide (LPS; 50 microg/kg ip) at two ambient temperatures (Ta; 21 and 31 degrees C). Young rats mounted equivalent fevers at both Tas [peak body temperatures (Tb) of 38.3 and 38.7 degrees C, respectively]. The Tb of old rats was not different from baseline (37.3 degrees C) after LPS at Ta 21 degrees C, whereas, at 31 degrees C, their Tb rose to a mean peak of 38.4 degrees C. We also measured the associated thermoregulatory responses by use of calorimetry. At 21 degrees C, young rats developed a fever by increasing both O2 consumption and heat conservation. Old rats did not become febrile, and O2 consumption fell by 15%. Heat loss was the same in old and young rats. At 31 degrees C, young and old rats developed similar fevers with similar increases in heat production and conservation. Our results suggest that the lack of LPS fever in old rats at 21 degrees C is due mainly to the lowered metabolic rate.     

Irreversibility of chilling injury in zucchini squash (Cucurbita pepo L) could be a programmed event long before the visible symptoms are evident

Zucchini fruits were subjected to 2.5 or 10 degrees C for 16d, followed by transfer to 20 degrees C for 24h in order to evaluate the relationship between ripening pattern, measured as CO(2) evolution and ethylene (C(2)H(4)) production, and metabolic heat production (q). Chilling injury (CI) visible symptoms were evident after 8d at 2.5 degrees C, but none were recorded on fruits kept at 10 degrees C. In fruits held at 10 degrees C, q, C(2)H(4) production, and CO(2) evolution diminished in the course of 16d, whereas in those at 2.5 degrees C CO(2) evolution showed an early burst peaking at 8d. Both C(2)H(4) production and q also showed a burst at 2.5 degrees C but they started at 4 and 8d, respectively, and peaked at 12d. The results showed that irreversibility of chilling injury in zucchini could occur long before the appearance of visible symptoms, although the metabolic activity accompanying the irreversibility process was not noticeable by isothermal calorimetry.     

Inhibitory effects of hyperthermia on mechanisms involved in autoresuscitation from hypoxic apnea in mice: a model for thermal stress causing SIDS.

The physiological mechanisms that might be involved in an association between heat stress and sudden infant death syndrome (SIDS) are obscure. We tested the hypothesis that a combination of acute hypoxia and elevated body temperature (T(B)) might prevent autoresuscitation from hypoxic apnea (AR). We exposed 21-day-old mice (total = 216) to hyperthermia (40.5-43.5 degrees C), hypoxia, or a combination of the two. Neither hyperthermia alone (40.5-42.5 degrees C) nor hypoxia alone was found to be lethal, but the combination produced failure to AR during the first hypoxic exposure with increasing frequency as T(B) increased. The ability to withstand multiple hypoxic exposures was also reduced as T(B) increased. In contrast, heat stress causing moderate T(B) increase (40.5 degrees C) had no effect on survival. Increased T(B) (43.5 degrees C) reduced gasping duration and number of gasps. It increased heart rate during anoxia but did not alter gasping rate. Furthermore, the oxygen-independent increase in heart rate observed before gasping failure was usually delayed until after the last gasp in hyperthermic animals. Mild dehydration occurred during T(B) elevation, but this did not appear to be a primary factor in AR failure. We conclude that a thermal stress, which by itself is nonlethal, frequently prevents AR from hypoxic apnea. This may be due, at least in part, to decreased gasp number and duration as well as to hyperthermia-related asynchrony of reflexes regulating heart and gasping frequencies during attempted AR.     

Survival and metabolic responses to freezing by the water frog (Rana ridibunda)

We studied the ability of the marsh frog Rana ridibunda to survive freezing exposure and the associated subsequent metabolic variations. This species that typically overwinters under water tolerates the conversion of 55% of its body water into ice. This ice content is attained after a few hours (between 8 and 36 hours depending on the mass of the individual and the environmental temperature) but death occurs at greater than 58% ice. Freezing stimulated a significant increase in blood carnitine and trimethylamine levels (respectively 4.5+/-2.5 and 0.5+/-0.2 micromol.l(-1) for controls versus 27.0+/-18.9 and 3.6+/-4.1 micromol.l(-1) after thawing) but these increases had no significant effect on plasma osmolality which was unchanged between control and freeze exposed frogs (252.6+/-20.3 versus 240.2+/-25.0 mOsmol.l(-1), respectively). Freezing also induced a significant dehydration of heart, liver and muscles (respectively 4.2, 3.2 and 2.8%) but the observed levels are low compared to values found in highly freeze tolerant species. This species could be classified as "partially freeze tolerant" enduring the transformation of a significant part of its body water into ice but not the completion of the exotherm. The existence of freeze tolerance in an aquatic hibernator that does not accumulate cryoprotectant, exhibiting low organ dehydration after freezing and low hypoxia tolerance, raises the possibility that a tolerance of nearly 60% ice within the body is common among anurans.     

Comparative metabolic responses to prolonged cooling in precocial duck (Anas domestica) and altricial pigeon (Columba domestica) embryos

1. Embryos and hatchlings of the duck and pigeon were exposed to a lowered temperature for 6 hr. The oxygen consumption (MO2) was measured before and after cooling and the ratio of the two was compared with that predicted for a temperature coefficient of 2 (Arrhenius value). 2. Late prenatal ducks kept the MO2 above the Arrhenius value at 28 degrees C, while the MO2 of pigeon hatchlings became the same as the Arrhenius value even at 32 degrees C. 3. Thus, incipient homeothermic ability appears in the duck during prenatal development, but it is not evident in the pigeon even after emergence from the shell. The precocial chicken and semi-precocial noddy previously studied are intermediate in their metabolic response between the duck and the pigeon.     

Some ecological parameters of Ctenocephalides felis strongylus (Jordan, 1925) (Siphonaptera: Pulicidae)

Among the fleas of medico-veterinary interest, Ctenocephalides felis (Bouché, 1 835) is the one most studied. This taxon includes two subspecies: Ctenocephalides f. felis, and Ctenocephalides f. strongylus (Jordan, 1925); only C. f. felis has been the subject of almost all the studies available. We were, thus, interested in C. f. strongylus which can be regarded as the species of substitution of C. f. felis on the African continent. The purpose of our work was to establish some biological parameters such as: hatching of eggs, cycle of development and emergence of adults. These data were compared with those available on C. f. felis. With temperatures ranging between 19 degrees C and 29 degrees C and a relative humidity (HR) of 75 % +/- 5, the hatching rates of eggs observed from the two subspecies of C. felis, are higher than 88 %. The optimal temperature of eggs hatching for C. felis is 29 degrees C, with more than 70 % of hatching obtained in 1-2 days after the laying. The larval developments of the two subspecies are almost identical and function of the temperature 18-9 days with 27 degrees C). Only differs the minimal duration of the progressive cycle. For C. f. strongylus, it lasts in 16-17 days at 29 degrees C, 20-21 days at 27 degrees C and 38 days at 19 degrees C. For C. f. felis, published values give report of 15 days at 27 degrees C and 17 days at 24 degrees C. The emergence of adults of C. f. strongylus takes eight to ten days between 19 degrees C and 29 degrees C, while data published on C. f. felis are about 26 days at 19 degrees C and 15 days at 27 degrees C.