Trissolcus semistriatus is an important egg parasitoid of the sunn bug, Eurygaster integriceps. Conservation and the supportive augmentation of populations of egg parasitoids appears to offer high potential for the biological control of sunn bug in an integrated pest management system. The present study was conducted to determine the host preference of T. semistriatus on various heteropteran host eggs. When each host species was examined separately, the eggs of E. integriceps, Dolycoris baccarum, Graphosoma lineatum, Carpocoris pudicus and Holcostethus vernalis, were parasitized at high levels, namely 88.0, 83.6, 94.8, 87.3 and 80.8%, respectively, whereas a smaller portion of Eurydema ornatum eggs were parasitized (24.0%). There was no parasitism in Nezara viridula eggs by T. semistriatus. Similar high rates were recorded for the percentage of adult emergence in each host species, with the exception of E. ornatum. The average development time was shorter for males than for females. The average development period for both male and female was significantly longer in eggs of E. ornatum than in those of the other host species. These results and observations recorded during the experiments showed that G. lineatum and D. baccarum were available, cheap hosts and it was demonstrated that these hosts could be used for the mass production of egg parasitoids.

Various heteropteran host eggs stored under two low-temperatures were tested in the laboratory for their usability in the production of sunn pest egg parasitoid, Trissolcus semistriatus. Parasitism, adult emergence rate and development time were assesed on stored and fresh eggs of Eurygaster integriceps, Dolycoris baccarum, Graphosoma lineatum and Eurydema ornatum. Masses of fresh host eggs in microcentrifuge tubes were maintained at +6°C and )20°C. Every 30 days, 50 eggs of host species were exposed to parasitism by T. semistriatus. The host eggs stored at 6°C remained viable to parasitism by T. semistriatus up to 2 months, while those of stored at )20°C were parasitized at high rates up to 4 months, alhough succesful parasitism rates decrease with time. However, it was indicated that both fresh or stored E. ornatum eggs were not preferred to parasitism by the parasitoid. A longer development time from egg to adult was observed in stored eggs under two tested storage techniques when compared with fresh eggs.

The effects of temperature on age-specific fecundity and life table parameters of the egg parasitoid Trissolcus semistriatus (Nees, 1834) (Hymenoptera: Scelionidae) were examined under four constant temperature conditions (17, 20, 26 and 32°C), using eggs of the sunn pest Eurygaster integriceps Puton, 1881 (Hemiptera: Scutelleridae), an important pest of wheat, as hosts. The intrinsic rate of increase increased linearly, while the mean generation time and the doubling time decreased with increases in temperature. The net reproductive rate, however, varied without clear correlation with temperature. Fecundity tended to be higher at higher temperatures. The total number of eggs per female was estimated as 52.0 and 116.4 eggs, respectively, at 17°C and 32°C, with the highest fecundity rate during the first day of oviposition. The oviposition rate fluctuated from 4.4 to 14.3 eggs per day. Oviposition and postoviposition periods and longevity decreased when temperature increased. Maximum longevity for females was 21.6 days at 20°C, and female parasitoids lived longer than males at all temperatures. The development period ranged from 7.1 days (32°C) to 35.6 days (17°C) for males and from 8.4 days (32°C) to 37.2 days (17°C) for females. The development of female T. semistriatus required 166.7 degree-days (DD) above a theoretical threshold of 11.8°C and the development of males required 142.9 DD above 13.1°C. The numbers of generations per year for female and male T. semistriatus, given the temperature in Tekirdag, Turkey, were estimated to be 9.0 and 8.8, respectively. The potential of the egg parasitoid for the control of E. integriceps is discussed.

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In order to understand the effects of temperature on Trissolcus simoni, some parameters of the life tables of adult parasitoids were investigated under laboratory conditions. The following parameters were measured (the values in parentheses were obtained at 20, 26, and 32°C temperatures, respectively): net reproductive rate (R o =37.785, 40.301, and 58.299), intrinsic rate of population increase (r m =0.111, 0.221, and 0.325), generation time (T=32.77, 16.60, and 12.49 days), doubling time (DT=6.245, 3.136, and 2.133), and finite rate of increase (k=1.117, 1.247, and 1.385). Fecundity increased with increasing temperature. The values for total number of eggs deposited per female were 50.1, 64.1, and 68.1, and average female longevity was 24.2, 13.8, and 11.1 days at 20, 26, and 32°C, respectively. Temperature had a significant effect on longevity and oviposition and post-oviposition periods. The results of the study are discussed and compared with life-table parameters of other scelionids.

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Abstract:In this paper, we give the necessary and sufficient conditions for non-null curves with non-null normals in 4-dimensional Semi-Euclidian space with indeks 2 to be osculating curves. Also we give some examples of non-null osculating curves in E 4 2 .