Effect of Temperature on Life Table Parameters of Predatory Thrips Scolothrips longicornis (Thysanoptera: Thripidae) Fed on Twospotted Spider Mites (Acari: Tetranychidae)

Abstract

Environmental variables such as temperature are important factors that affect the efficiency of biological control agents. This study examined the effect of temperature on the sex ratio, longevity, oviposition periods, fecundity and life table parameters of the predatory thrips Scolothrips longicornis Priesner (Thysanoptera: Thripidae) fed on twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), at six constant temperatures: 15, 20, 26, 30, 35, and 37 degrees C. Approximately 75% of the progeny were female, except at 37 degrees C, at which temperature the proportion of males increased. Adult longevity as well as the preoviposition, oviposition, and postoviposition periods decreased significantly with temperature. Thus, adults lived for approximately 5 wk at 15 degrees C and < 1 wk at 37 degrees C with preoviposition, oviposition, and postoviposition periods ranging from 6.4 to 0.4, 24.4-3.1, and 7-0.8 d between the two temperature extremes, respectively. The maximum (56.48 eggs) and minimum (11.69 eggs) value of total fecundity was recorded at 26 and 37 degrees C, respectively. The intrinsic rate of natural increase (r(m)) of S. longicornis increased linearly with increasing temperature from 0.056 d(-1) at 15 degrees C to 0.310 d(-1) at 35 degrees C. The lower temperature threshold for the population increase of S. longicornis was estimated to be around 5 degrees C. The data suggest that the upper temperature threshold for the predatory thrips is approximately 37 degrees C. The results showed that populations of S. longicornis are able to develop at a broad range of temperatures and that this predator is well adapted to the high temperatures that occur in the Mediterranean region.

Intraguild predation among Scolothrips longicornis (Thysanoptera: Thripidae), Neoseiulus californicus and Typhlodromus bagdasarjani (Acari: Phytoseiidae) under laboratory conditions

“…Populations of S . longicornis are able to develop at a broad range of temperatures and well adapted to high temperatures in Mediterranean region (Pakyari et al ., , ).…”

Effect of Different Temperatures on Consumption of Two Spotted Mite,Tetranychus urticae, Eggs by the Predatory Thrips,Scolothrips longicornis

“…The pattern reflects a combination of the linearly decreasing female oviposition period with increasing temperatures (Table 2, Pakyari et al 2011b), and the nonlinear temperature dependent function for daily prey consumption. Overall the total consumption by ovipositing females could, however, be described by linear regression (P = 0.005) (Table 2).…”

“…Gerlach and Sengonca 1985; Zhang and Croft 1994; Kazak 2008), the predation capacity of S. longicornis demonstrated here holds good promises for the exploitation of this predatory thrips for control of T. urticae in crops where the temperature range between 20° C and 30–35° C, as is the case, for example, in Mediterranean greenhouses. Thus, although the innate capacity for increase of S. longicornis has been documented (Pakyari et al 2011b) to be generally lower than that of phytoseiid mites (e.g. Sabelis 1985, 1991), the higher predation capacity may compensate for this.…”

“…The different larval instars were distinguished based on larval size, and on the presence of larval exuviae. The data on juvenile development and duration of the female phases were reported in Pakyari et al (2011a) and Pakyari et al (2011b), respectively, but are included here in order to be held in comparison with the results on consumption.…”

“…S. longicornis occurs in the Middle East, India, and North America (Priesner 1950; Gilstrap and Oatman 1976; Alavi and Kamali 1996). In Iran, this species is a commonly recorded predator of spider mites in outdoor bean, cucumber, and eggplant (Aydemir and Toros 1990; Pakyari et al 2011a, b; Pakyari and Fathipour 2009). Some aspects of the biology of S. longicornis (functional response, mutual interference, life table characteristics, and feeding activity) have been studied (Gerlach and Sengonca 1986; Sengonca and Weigand 1988; Pakyari et al 2009; Pakyari and Fathipour 2009), but the influence of temperature on prey consumption has not been examined to date.…”