Features of the structure of hymenoptera associated with miniaturization: 2. Anatomy of Trichogramma evanescens (Hymenoptera, Trichogrammatidae)

2016 ◽  
Vol 96 (4) ◽  
pp. 419-431 ◽  
Author(s):  
A. A. Polilov
2019 ◽  
Vol 29 (1) ◽  
Author(s):  
Naglaa F. Abdel-Hameid ◽  
I. R. M. Elzoghby ◽  
A. L. Mehany ◽  
W. A. A. Sayed

AbstractThe performance of parasitism by the egg parasitoid, Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) on eggs of Angoumois grain moth, Sitotroga cerealella Olivier (Lepidoptera: Gelechiidae) was investigated under cold storage and gamma irradiation treatments of the host eggs. Cold storage treatment could improve the parasitoid mass rearing techniques and reduced the costs of biological control programs, while gamma irradiation might be used as a supplementary support at the times of high demand. The suitability of the S. cerealella eggs, stored at – 20 °C for 0.5, 1, or 2 h. as a host for T. evanescens was evaluated. The sensitivity of S. cerealella eggs to gamma irradiation treatments and the acceptability of irradiated eggs for parasitism by T. evanescens females for the parental P and F1 generations were examined. The results revealed that parasitism was drastically reduced more than adult’s emergence and sex-ratio (% of females) after cold storage periods of S. cerealella eggs. Moreover, the parasitism percentages were relatively reduced to (97.1, 96.1, 93.03, and 92.7 %) after irradiating the S. cerealella eggs at 40, 60, 80, and 100 Gy, respectively than the control (97.3% emergence). The percentages of emergence and females’ percent were slightly decreased by gamma irradiation doses, while, equal preferred by the F1 generation of parasitoid that produced from irradiated S. cerealella eggs.


Author(s):  
Asea Timus ◽  
N. Croitoru

Every year, the demand of ecological products in the world is increasing more and more. Republic of Moldova also aspires to expand the areas of agricultural crops to get production with the "ecological" status. The sweet corn, is one of these cultures and every year the areas increase. However, because of the considerable develop of harmful insects on cultural fields, the damage reaches up to 15-20 % and more it is necessary to take measures of struggle. One of these, is a biological method and in this case it has appeared effective. For the period of sweet corn cultivation, excepting for the technology observance of cultivation of the given culture, there have been used biological methods of struggle against harmful insects. Depending on climatic conditions of each zone of the country where it is grown up this culture, different species of harmful insects develop. In R. Moldova, begining with year 2000, have been registered the following harmful species of insects on sweet corn: Aphis spp. (Aphididae); Agrotis spp. (Elateridae); Blaps halophila Fisch. (Tenebrionidae); Phylotreta spp. (Chrysomelidae); Helicoverpa armigera Hubner (Noctuidae) Ostrinia nubilalis Hb. (Pyraustidae). The constant useful fauna which develops due to these harmful species is: Nabis spp. (Miridae); Chrysopa spp., (Chrysopidae); Coccinella spp. (Coccinelidae) and others. That is why, annually are let out individuals from species Trichogramma evanescens W., to reduce the number of harmful species H. armigera Hubner. This species annually damages on different cultures, including on sweet corn. The results on released trichogrammas in 2005, for struggle against harmful species H. armigera Hubner, are presented in this work.


Parasitology ◽  
1937 ◽  
Vol 29 (4) ◽  
pp. 539-553 ◽  
Author(s):  
George Salt

1. Nearly a quarter of a million eggs of Sialis lutaria were collected at Cambridge in 1936. About 0·6 per cent of them were attacked by a parasite.2. The egg-parasite of Sialis is distinct from Trichogramma evanescens, and is to be called T. semblidis (Aurivillius).3. The male of Trichogramma semblidis occurs in two forms. Neither consists merely of imperfect or degenerate individuals of the other, for the two forms are equally large and differ constantly and fundamentally in several characters. The species, therefore, exhibits true dimorphism.4. Rearing experiments involving isolated pure lines show that it is principally the host that determines which form of the parasite shall emerge. Males reared on Sialis are of the apterous form; those reared on three species of Lepidoptera are of the winged form.5. The dimorphism of T. semblidis is discussed in relation to other examples of dimorphism in the Hymenoptera. It is shown to have several features of special interest.


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