Temperature influences walking speed and walking activity of Trichogramma brassicae (Hym., Trichogrammatidae)

Abstract

Walking speeds and walking activities (walking time divided by total time) of Trichogramma brassicae were determined at 12, 16, 20 and 25°C. Walking speed was measured during a 5‐min period, and walking activity over a 4‐day period. Both walking speed and walking activity were strongly influenced by temperature. Walking speed increased linearly with the temperature and was twice as high at 20 as at 12°C. At 25°C, walking activity was high during the whole day, at 20 and 16°C it decreased during the afternoon, whereas at 12°C the wasps became most active only at noon or later. At low temperatures, there was a strong individual variation in walking activity. At 25°C, T. brassicae was active most of the time, so the area searched per time unit can only increase at temperatures above 25°C if walking speed increases. At temperatures below 20°C, searching was more restricted by low walking activity than by low walking speed. Even disregarding other effects of temperature, the reduction in walking speed and walking activity at suboptimal temperatures means that T. brassicae can only search half of the area at 20°C, and only one‐seventh at 15°C that it can search at 25°C.

Nocturnal parasitism of moth eggs byTrichogrammawasps

“…Biever (1972), Boldt (1974) and Suverkropp et al (2001) found a similar effect of temperature on the walking activity of T. evanescens, T. brassicae, T. minutum and T. semifumatum Perkins (Hymenoptera: Trichogrammatidae). Pak and van Heiningen (1985) compared the oviposition rates of T. maidis Pint.…”

“…Temperature influences not only walking speed and walking activity (Suverkropp, Bigler, & van Lenteren, 2001), and flight activity (Forsse et al, 1992), but also parasitism (Maceda, Hohmann, & dos Santos, 2003;Pak & van Heiningen, 1985). In general, activity increases with higher temperatures until a certain optimal temperature is reached, after which activity decreases.…”

Does Wolbachia infection affect Trichogramma atopovirilia behaviour?

“…At 40 °C, the T. evanescens wasps died. Suverkropp et al (2001) observed a significant effect of the temperature on T. brassicae walking speed. At 20 °C the average walking speed was twice as high as at 12 °C.…”

“…This is defined as the fraction of females observed that were active at the moments of observation (Suverkropp et al, 2001) and was analysed at three temperatures (15, 20 and 25 °C). One day old infected and mated cured female T. atopovirilia wasps were placed into vials (75 mm long and 10 mm diameter) with a drop of honey and closed with cotton wool.…”

“…Although a large number of traits have been studied to improve biological control strategies such as searching behaviour, dispersal, emergence rate of the parasitised eggs, percentage of non-deformed females, walking speed and walking activity (Burbutis et al, 1977;Kot, 1979;Greenberg, 1991;Kazmer and Luck, 1995;Cerutti and Bigler, 1995;Romeis et al, 1998;Drost et al, 2000;Suverkropp et al, 2001) few traits have been studied in Trichogramma species infected with Wolbachia. A single study (Silva et al, 2000) was done to test the biocontrol performance of Wolbachia infected versus cured wasps in a greenhouse setting.…”