Development of Microplitis rufiventris Kok at different temperatures

1980 ◽  
Vol 94 (3) ◽  
pp. 739-740 ◽  
Author(s):  
E. M. Hegazi ◽  
M. O. Kolaib ◽  
M. I. Abd-El Fattah

The solitary larval parasite Microplitis rufiventris Kok was recorded for the first time in Egypt by El-Minshawy (1963), parasitizing the lesser cotton leafworm, Spodoptera exigua Hbn. Since it could be an effective summer parasite of the cotton leaf-worm, Spodoptera littoralis Boisd., studies on aspects of its biology by Hegazi (1976), and Hegazi, Hammad & El-Minshawy (1977) have been extended to include the effect of temperature on its development.

2015 ◽  
Vol 95 (6) ◽  
pp. 1237-1243 ◽  
Author(s):  
Sílvia Lourenço ◽  
Ana Moreno ◽  
Luís Narciso ◽  
João Pereira ◽  
Rui Rosa ◽  
...  

The estimation of age and growth of cephalopod stocks is a key issue for their sustainable management. Recently, several studies have successfully validated the daily deposition of growth rings in the vestigial shell or stylets of several octopus species.Octopus vulgariseggs were incubated at two different temperatures, 18 and 22°C, until hatching to determine stylet size at hatching and assess the effect of temperature in the stylet dimensions. The 3-day-old hatchlings were sectioned transversally and 6 μm sections were stained to enhance the stylet position and visibility. The sections were observed under transmitted light microscopy at a magnification of 1000×, and the stylets identified as blue/green structures inside the mantle–funnel retractor muscle. The transversal sections of the whole paralarvae allowed the diameter of the embryonic stylet of an octopus species to be measured for the first time. The mean stylet diameter in 3-day-old paralarvae is 3.99 μm independently of the thermal conditions. Moreover, significant differences in stylet size between captive and wild paralarvae were observed; the latter showed significantly larger stylets, an indication that they are over 3 days old. Our results also indicate that the stylet nucleus is much smaller than previously thought based on measurements in stylets of juveniles and adults.


2020 ◽  
Vol 10 ◽  
Author(s):  
Soad F. E. Mohsen ◽  
Moustafa A. Abbassy ◽  
Hamdy K Abou-Taleb ◽  
Entsar I. Rabea

Background: The production of insecticidal proteins is one of the greatest vital direct defense responses in plants against the attack by phytophagous insects. One particular class of entomotoxic proteins present in many plant species is lectins that used against a wide range of important insects. Aim: The insecticidal activity of two lectins from seeds of white kidney bean (Phaseolus vulgaris) and soybean (Glycine max) on the growth, development and survival of the cotton leafworm, Spodoptera littoralis Boisd. (Lepidoptera: Noctuidae) was studied. Methods: Lectin products were isolated and purified using ammonium sulfate precipitation. Insecticidal activity, growthinhibitory and physiological effects on the differential haemocyte count of lectin products were evaluated against S. littoralis. In vivo effects of lectin products on some S. littoralis enzymes were also determined. Results: Lectin contents in 250 g seeds was 700 and 500 mg in soybean and white kidney bean, respectively. The total protein concentrations were 160-163 and 118-120 mg/mL in soybean and white kidney bean, respectively. The insecticidal activity of lectin products exerted a strong effect on the larval weight gain and the reduction of the weight reached to 75.25%. Furthermore, the other developmental stages of pupation and adult formation were also affected. Elongated larval duration was noticed since larval duration was 24.8 days compared with control (12.0 days). A complete pupation (100%) was recorded in the control however, a significant decrease in pupation was found to be 54.0% in treated larvae. Lectin products increased the average number of 123.9 haemocytes (123.9) compared to the control (94.4 haemocytes/field). In addition, lectin products inhibited the activity of total proteases, α-amylase, GST and total esterases. Conclusion: It can be concluded that the lectins with high potential for the use in pest control strategies based on their activity towards the cotton leafworm, S. littoralis. These findings suggest that lectin products are interesting tools for integrated pest management in important agriculture crops.


Author(s):  
D. T. Gauld ◽  
J. E. G. Raymont

The respiratory rates of three species of planktonic copepods, Acartia clausi, Centropages hamatus and Temora longicornis, were measured at four different temperatures.The relationship between respiratory rate and temperature was found to be similar to that previously found for Calanus, although the slope of the curves differed in the different species.The observations on Centropages at 13 and 170 C. can be divided into two groups and it is suggested that the differences are due to the use of copepods from two different generations.The relationship between the respiratory rates and lengths of Acartia and Centropages agreed very well with that previously found for other species. That for Temora was rather different: the difference is probably due to the distinct difference in the shape of the body of Temora from those of the other species.The application of these measurements to estimates of the food requirements of the copepods is discussed.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aiyan Guan ◽  
Inge Van Damme ◽  
Frank Devlieghere ◽  
Sarah Gabriël

AbstractAnisakidae, marine nematodes, are underrecognized fish-borne zoonotic parasites. Studies on factors that could trigger parasites to actively migrate out of the fish are very limited. The objective of this study was to assess the impact of different environmental conditions (temperature, CO2 and O2) on larval motility (in situ movement) and mobility (migration) in vitro. Larvae were collected by candling or enzymatic digestion from infected fish, identified morphologically and confirmed molecularly. Individual larvae were transferred to a semi-solid Phosphate Buffered Saline agar, and subjected to different temperatures (6 ℃, 12 ℃, 22 ℃, 37 ℃) at air conditions. Moreover, different combinations of CO2 and O2 with N2 as filler were tested, at both 6 °C and 12 °C. Video recordings of larvae were translated into scores for larval motility and mobility. Results showed that temperature had significant influence on larval movements, with the highest motility and mobility observed at 22 ℃ for Anisakis spp. larvae and 37 ℃ for Pseudoterranova spp. larvae. During the first 10 min, the median migration of Anisakis spp. larvae was 10 cm at 22 ℃, and the median migration of Pseudoterranova spp. larvae was 3 cm at 37 ℃. Larval mobility was not significantly different under the different CO2 or O2 conditions at 6 °C and 12 ℃. It was concluded that temperature significantly facilitated larval movement with the optimum temperature being different for Anisakis spp. and Pseudoterranova spp., while CO2 and O2 did not on the short term. This should be further validated in parasite-infected/spiked fish fillets.


Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 134
Author(s):  
Ana Isabel Galván ◽  
Alicia Rodríguez ◽  
Alberto Martín ◽  
Manuel Joaquín Serradilla ◽  
Ana Martínez-Dorado ◽  
...  

Dried fig is susceptible to infection by Aspergillus flavus, the major producer of the carcinogenic mycotoxins. This fruit may be contaminated by the fungus throughout the entire chain production, especially during natural sun-drying, post-harvest, industrial processing, storage, and fruit retailing. Correct management of such critical stages is necessary to prevent mould growth and mycotoxin accumulation, with temperature being one of the main factors associated with these problems. The effect of different temperatures (5, 16, 25, 30, and 37 °C) related to dried-fig processing on growth, one of the regulatory genes of aflatoxin pathway (aflR) and mycotoxin production by A. flavus, was assessed. Firstly, growth and aflatoxin production of 11 A. flavus strains were checked before selecting two strains (M30 and M144) for in-depth studies. Findings showed that there were enormous differences in aflatoxin amounts and related-gene expression between the two selected strains. Based on the results, mild temperatures, and changes in temperature during drying and storage of dried figs should be avoided. Drying should be conducted at temperatures >30 °C and close to 37 °C, while industry processing, storage, and retailing of dried figs are advisable to perform at refrigeration temperatures (<10 °C) to avoid mycotoxin production.


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