Thermoperiodic effects on diapause of Sesamia nonagrioides (Lepidoptera: Noctuidae)

Abstract

Abstract. The role of the thermophotoperiod on larval diapause induction and development of Sesamia nonagrioides was investi gated under laboratory conditions. The incidences of diapause by TC 1 2 :1 2 thermoperiods under DD, in which the thermophase was 30°C and cryophases varied from 10 to 25°C, were compared to the effects of thermophotoperiods with the same configuration. Higher incidences of diapause were recorded when larvae were exposed to thermophotoperiods with cryophases of 15-25°C, than under thermoperiods under constant darkness. In addition, larvae exhibited significantly lower percentages of diapause when exposed to cryophases < 15°C under either thermo-or thermophotoperiodic condition. Diapausing larvae when exposed to photope riods 16L : 8D h and different temperatures of 25-30°C proceeded to development in 14-16 days. Moreover time needed for the pupation of diapausing larvae after their transfer to 12L : 12D h, was reduced from approximately 49 to 12 days depending on tem peratures of exposures (25-30°C). Diapause termination was also compared under 12L : 12D h and constant temperature of 25°C or a thermoperiod of TC 12:12 (30°: 20°). Days needed for pupation at constant temperature or under the mentioned thermoperiodic regime, were approximately the same when the high temperature of the thermoperiod coincided with the scotophase, while with the co-occurrence of the high temperature of the thermoperiod and the photophase significantly additional time was needed for diapause development. Significantly shorter time was also needed for diapause development after exposure of diapausing larvae to continuous light, than to continuous darkness under 25°C. Thermoperiods of different amplitudes with the same mean temperatures proved that the higher temperature of scotophase led to higher rate of diapause development in spite of the relatively low temperature of the pho tophase tested. It is suggested that thermoperiod could hasten the time needed for diapause development, but it is not the crucial factor for the termination of diapause.

Monitoring of Sesamia nonagrioides resistance to MON 810 maize in the European Union: lessons from a long‐term harmonized plan

“…and abiotic (weather, planting date, etc.) factors . The widespread planting of Bt crops has been associated with the decline since 2002 of population levels of the European corn borer, O. nubilalis , in corn in the USA and the cotton bollworm H. armigera (Hübner) in China .…”

“…factors. [48][49][50][51][52][53] The widespread planting of Bt crops has been associated with the decline since 2002 of population levels of the European corn borer, O. nubilalis, in corn in the USA 54 and the cotton bollworm H. armigera (Hübner) in China. 55 In the case of S. nonagrioides, there is insufficient historical data on population dynamics to support the idea of area-wide suppression by Bt maize.…”

Diapause induction in Eotetranychus smithi (Acari: Tetranychidae): effect of average temperature, but not of thermoperiod

“…Species showing thermoperiodism sense the ratio of day to night of a given thermoperiod and anticipate the approach of unfavourable conditions. Thermoperiodic regulation of diapause has been reported in various species, most of which enter diapause in response to a short thermoperiod that is composed of a short thermophase (T) and a long cryophase (C) (Saunders, 1973; Beck, 1982, 1983; Brown & Phillips, 1990, 1991; Fantinou & Kagkou, 2000; Fantinou et al ., 2002; Koštál et al ., 2016). For example, in the predacious mite Amblyseuis andersoni (Chant) (Acari: Phytoseiidae), diapause incidence was 73% under a thermoperiod regime that consisted of a 12‐h thermophase of 27 °C and a 12‐h cryophase of 15 °C, but it was 0% under a thermoperiod regime that consisted of a 16‐h thermophase and an 8‐h cryophase.…”

Abundance ofSesamia nonagrioides(Lef.) (Lepidoptera: Noctuidae) on the Edges of the Mediterranean Basin

“…In view of this, on 15 August in the northern regions of Europe, the longer photoperiods induce lower percentages of diapause, whilst the shorter ones occurring in southern Europe induce higher percentages. These results may seem contradictory, because in the northern regions S. nonagrioides larvae enter diapause earlier than in the southern regions, but the explanation could be that temperature has been reported to play a significant role in diapause induction [20,50,55,58].…”