Influence of temperature on the restoration of the ability of Trichogramma principium to undergo diapause

• Published in: Journal of insect physiology Vol. 132; p. 104271
• Main Authors: Reznik, Sergey Ya, Voinovich, Natalia D.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2021
• Subjects: Development; Diapause; Interval timer; Maternal effect; Temperature; Trichogramma; Development; Temperature; Maternal effect; Interval timer; Diapause; Trichogramma
• ISSN: 0022-1910; 1879-1611
• DOI: 10.1016/j.jinsphys.2021.104271

[Display omitted] •The progeny of post-diapause Trichogramma females are unable to enter diapause.•The incidence of diapause gradually increases over sequential generations.•The diapause ability restoration rate linearly increases with temperature.•The lower temperature threshold of this response is close to that for development.•The interval timer is not connected with the photothermal regulation of diapause. It is known that the progeny of post-diapause females of some insects are insensitive to diapause-inducing stimuli. In aphids the duration of the ‘interval timer’ (the restoration of the ability to diapause) decreases with temperature. However, the parameters of this temperature dependence are unknown. We investigated the restoration of the ability to undergo diapause in 9–16 sequential post-diapause generations of the egg parasitoid Trichogramma principium Sug. et Sor. (Hymenoptera: Trichogrammatidae) over a period of 120–150 days at different constant and variable temperatures. This revealed a strong linear correlation between mean temperature and the rate of the restoration of the ability to diapause. The lower temperature threshold of this dependence was not significantly different from that of the thermal dependence of the rate of preimaginal development. The restoration rate depended on the mean temperature for the whole period of development rather than on the temperature conditions during the development of the thermosensitive stages determining the incidence of diapause in the progeny. The results of this study indicate that the duration of the interval timer is determined by the rate of development (or, more generally, by the rate of metabolism) rather than by the mechanisms controlling the photothermal regulation of diapause.