Effect of temperature on egg hatching and survival of larvae of Anisakis simplex B (Nematoda: Ascaridoidea)

1992 ◽  
Vol 70 (2) ◽  
pp. 274-279 ◽  
Author(s):  
John Brattey ◽  
Kirsten J. Clark

Eggs of the parasitic nematode Anisakis simplex B, obtained from a white-beaked dolphin (Lagenorhynchus albirostris Gray), were incubated in seawater at constant temperatures from −0.7 to 24.3 °C and hatching times determined. Eggs hatched at all temperatures except −0.7 °C. The number of days until hatching ranged from 3 at 24.3 °C to 74–81 at 1.9 °C. There was a declining curvilinear relationship between temperature and both hatching time and duration of the hatching period. The hatching period increased and became more variable with decreasing temperature and ranged from 5 days at 24.3 °C to 55–72 days at 3.8 °C. The percentage of eggs that hatched at each temperature was variable but generally fell in the range 30–60% and was not correlated with temperature. Survival times of hatched larvae peaked at 75–105 days at 8.6 °C, with a minimum of 3–8 days at 24.3 °C. Dimensions of eggs (length, width, volume) differed significantly among individual worms but were not correlated with worm size (wet weight). Egg hatching and larval survival characteristics indicate a species adapted to cold-temperate waters and are consistent with the known distribution of A. simplex B. Preliminary experiments indicated that harpacticoid copepods will ingest newly hatched larvae of A. simplex B and become infected, suggesting that these microcrustaceans may be involved in the life cycle of the nematode.

2017 ◽  
Vol 26 (1) ◽  
pp. 135-141
Author(s):  
Charles-Antoine Dedryver ◽  
Joël Bonhomme ◽  
Jean-François Le Gallic ◽  
Jean-Christophe Simon
Keyword(s):  

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Yunus Ayer ◽  
Joppy Mudeng ◽  
Hengky Sinjal

The objective of research was to determine the concentration of honey in sperm dilution  for improving hatching rate of egg and survival of nile tilapia larvae (Oreochromis niloticus).The number of fish used was five pairs broodstock. Dilution substance was NaCl and honey.  Observations were conducted on spermatozoa motility, fertility and egg hatching rate. Experimental design used was complete randomized design. Sperm dilution substance was prepare by disolving honey  (0 mL; 0,60 mL; 0,65 mL dan 0,70 mL) in 100 mL; 99,40 mL; 99,35 mL and  99,30 mL NaCl respectively.  Each dilution was homogenized using aerator for 15 minutes. Fertilization was done 12 hours after ovulation.  Egg hatching rate was observed after ovulation. Research results showed the use of honey had significant effet on egg hatching rate, but not on larval survival.  Treatment D (0,70 mL honey in 99,30 mL NaCl) had the highest hatching rate (77.33%). Dilution ratio 1:60 was the best indicated by spermatozoa motility 96.66%, fertility 71.65, hatching rate 70% and larval survival 81.67%   Keywords : honey, egg hatching rate, larval survival, Oroechromnis niloticus


1995 ◽  
Vol 74 (5) ◽  
pp. 2065-2076 ◽  
Author(s):  
H. R. Koerber ◽  
P. B. Brown

1. To test the hypothesis that subtotal deafferentation of dorsal horn cells can stimulate plastic changes in their receptive fields (RFs), diffuse deafferentation of the cat hindlimb dorsal horn was produced by transection of L7 or L6 and L7 dorsal roots. The following single-unit cutaneous low-threshold mechanoreceptor RF properties were compared between operated and control dorsal horns: 1) distance of RF center from tips of toes, 2) RF length-width ratio; and 3) RF area. 2. In both L7 and L6-L7 rhizotomized animals there was an increased incidence of silent electrode tracks in the most deafferented portion of the hindlimb map (the foot and toe representation). In the rhizotomized L6-L7 animals, there was also an increased incidence of symmetrically placed tracks in deafferented and control dorsal horns, in which cell RFs had no mirror-symmetrical components. In addition, cells in the lateral half of the L6 and L7 dorsal horns exhibited a proximal shift in the location of their RFs. In the rhizotomized L7 animals there was a distal shift of RFs in the L5 segment at long survival times. RFs had lower length-width ratios in L5 and L6 at short survival times and in L6 at long survival times. 3. In intact preparations, dorsal horn cells normally respond to inputs via single or small numbers of low-threshold cutaneous mechanoreceptors. Because these rhizotomies do not remove all inputs from any given area of skin, the deafferentations would produce only patchy loss of input from individual receptors. Therefore observed changes cannot be accounted for entirely by loss of afferent input, suggesting that some reorganization of dorsal horn cell RFs occurred. We conclude that the threshold stimulus for plastic change is less than total deafferentation of dorsal horn cells. At least some of the mechanisms underlying these changes may be active in normal animals in the maintenance of the somatotopic map or in conditioning.


Insects ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 228 ◽  
Author(s):  
Hannalene Du Plessis ◽  
Marie-Louise Schlemmer ◽  
Johnnie Van den Berg

The fall armyworm (Spodoptera frugiperda) is a pest of tropical origin which recently invaded Africa, the Far East and Australia. Temperature, therefore, plays an important role in its invasion biology, since this pest does not go into diapause. The aim of this study was to determine the development rate of S. frugiperda at different temperatures and to calculate the number of degree-days (°D) required for each stage to complete its development. This study was conducted at five different temperatures—18, 22, 26, 30 and 32 ± 1 °C. Larvae were reared individually in Petri dishes with sweetcorn kernels provided as food. The development rate of S. frugiperda increased linearly with increasing temperatures between 18 and 30 °C and larval survival was the highest between 26 and 30 °C. The optimal range for egg, larval and egg-to-adult development was between 26 and 30 °C. The optimum temperature with the fastest larval development rate and lowest mortality was at 30 °C. The pupal development period ranged between 7.82 and 30.68 days (32–18 °C). The minimum temperature threshold for egg and larva development was 13.01 and 12.12 °C, respectively, 13.06 °C for pupae and 12.57 °C for egg-to-adult development. Degree-day requirements for the development of the respective life cycle stages of S. frugiperda were 35.68 ± 0.22 for eggs, 204.60 ± 1.23 °D for larvae, 150.54 ± 0.93 °D for pupae and 391.61 ± 1.42 °D for egg-to-adult development.


2015 ◽  
Vol 81 (5) ◽  
pp. 891-897 ◽  
Author(s):  
Yang-Su Kim ◽  
Darys Isabel Delgado ◽  
Ing. Amado Cano ◽  
Yoshifumi Sawada

2013 ◽  
Vol 46 (6) ◽  
pp. 1522-1526 ◽  
Author(s):  
Mayra I. Grano-Maldonado ◽  
Hugo Aguirre-Villaseñor ◽  
Miguel Betancourt-Lozano ◽  
Emma J. Fajer-Ávila

1983 ◽  
Vol 115 (6) ◽  
pp. 663-666 ◽  
Author(s):  
Roy C. Beckwith

AbstractMortality of neonatal Douglas-fir tussock moth larvae varied from 0% to 100% depending on the rearing temperature and duration of food deprivation. Lower temperatures apparently favor larval survival under starvation conditions. For each period of food deprivation, mortality occurs earlier as the temperature increases; this shift to earlier mortality was significant at P <.01. Some implications are discussed.


2020 ◽  
Vol 8 (3) ◽  
pp. 213 ◽  
Author(s):  
Il-Kweun Oh ◽  
Seung-Woo Lee

Deiratonotus japonicus (D. japonicus) inhabits isolated locations and upstream brackish waters from Kanagawa Prefecture to Okinawa Prefecture in Japan. This species faces the threat of extinction because of changing habitat conditions. Our previous studies have shown that its complete larval development from hatching to metamorphosis consists of five zoeal stages and one megalopal stage. In this study, the effect of temperature on the survival and growth of larval development in D. japonicus under controlled laboratory conditions of 13, 18, 23, 24, 25, and 26 °C was investigated by rearing larvae (30 PSU; 12:12 h light/dark cycle; fed a diet of Brachionus plicatilis rotundiformis and Artemia sp. nauplii). The survival rates and developmental periods were measured for each larval stage. The highest survival rates were obtained at 18–24 °C. Metamorphosis to megalopa occurred at 23–25 °C. There were rapid and synchronous developments at 25–26 °C but delayed and extended developments at 13 °C. The molting period decreased with increasing temperature. With decreasing temperature, the beginning of the development and duration of molting was prolonged. In addition, there were very low survival rates at 13 °C and 26 °C in all zoeal stages. Our results indicate that the early larval stages of D. japonicus are well adapted to 18–24 °C, the range observed in the estuarine marine environment of the Kita River during the breeding season. Optimum larval survival and growth were obtained at 23 °C. Temperature significantly affected the survival rate, developmental period, and molting of the larvae. The relationship between the cumulative periods of development from hatching through individual larval stages (y) and temperatures (T) was described as a power function (y = a × Tb).


1970 ◽  
Vol 15 ◽  
pp. 41-46 ◽  
Author(s):  
MM Rahman ◽  
W Islam ◽  
KN Ahmed

Xylocoris flavipes (Reuter) is one of the dominant predators of many stored product insect pest including Cryptolestes pusillus. The influence of temperature on predator development, survival and some selected life history parameters was determined. Eggs laid/female (27.27±2.52) and egg hatching rate (%) (88.25±2.19) were highest at 30°C and lowest at 20°C (5.43±1.19 and 30.79±4.63%) respectively but no eggs laid at 15°C. Mortality among immature stages (%) was highest (51.71±1.48) at 35°C and lowest (24.25c±1.14) at 25°C. Developmental times decreasing with the increasing of temperature. Maximum numbers of progeny/female/day (3.55±0.76) were produced at 25°C and minimum (0.83±0.04) were at 20°C.The sex ratios (% female) of X. flavipes were 47.04, 56.68, 51.66 and 50.07 for 20, 25, 30 and 35°C respectively. Survivorship of ovipositing females was highest at 25°C but lowest at 35°C respectively. Key words: Xylocoris flavipes, Cryptolestes pusillus, life history, temperature, developmental time   doi: 10.3329/jbs.v15i0.2201 J. bio-sci. 15: 41-46, 2007


1990 ◽  
Vol 47 (11) ◽  
pp. 2228-2234 ◽  
Author(s):  
S. M. McGeachy ◽  
D. G. Dixon

The effects of water temperature (5 or 15 °C) on the toxicity of arsenate to rainbow trout were examined over an 11-wk period. The fish were exposed to nominal arsenate concentrations set as fixed proportions of the 144-h LC50s for arsenate at their respective temperature (5 °C: 0, 1.5, 18, and 36 mg∙L−1; 15 °C: 0, 1.5, 9, and 18 mg∙L−1). Arsenate toxicity was assessed in terms of mortality, total arsenic concentration, wet weight, condition factor, liver and muscle glycogen levels, hepato- and splenosomatic indices, and histopathology. Contrary to the previously reported relationship between acute toxicity and temperature, trout were more tolerant of chronic exposure to arsenate at 15 °C than at 5 °C. While the high-exposure concentration (5 °C, 36 mg∙L−1; 15 °C, 18 mg∙L−1) fish at both temperatures attained the same internal arsenic concentration (2 to 3 μg∙g−1), up to 50% of those fish tested at 5 °C died. The whole-body arsenic concentrations in moribund trout were found to vary between 4 and 6 μg∙g−1, suggesting that a critical arsenic body-concentration is reached before death or toxicant insult occur.


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