Biological Characteristics of Grapholita molesta (Lepidoptera: Tortricidae) Induced to Diapause in Laboratory

Abstract

In southern Brazil, Grapholita molesta (Busck) (Lepidoptera: Tortricidae) uses diapause as survival strategy during the winter (May–August). In our study, we evaluated the effect of diapause on biological characteristics of the species for 4 months in laboratory. Newly hatched larvae of G. molesta were induced to diapause changing the photoperiod and temperature (T) (12 ± 1°C), relative humidity (RH) (70 ± 10%), and a photophase of 12 h and, when they started diapause in the prepupal stage, the conditions were kept for 4 months. Afterwards, the insects were induced to finalize the diapause process at T 25 ± 1°C, RH 70 ± 10%, and a photophase of 16 h. We evaluated the duration and viability of the larval stages and pupae, pupae weight at 24 h and sex ratio (sr), periods of preoviposition, oviposition, and postoviposition; adult life span (males and females); fecundity (daily and total); embryonic period duration and eggs viability, comparing the data with insects nondiapause. The results show that diapause greatly affected the viability of pupal–adult stages of the population (21.8%) when compared with insects’ nondiapause (80.0%). Total fecundity (83.0 eggs) and mean life span (12.0 d) of insects diapause was significantly lower compared with insects nondiapause (173.0 and 17.0), respectively. However, these differences were not observed in the sr, which was similar to insects diapause (sr = 0.41) and insects nondiapause (sr = 0.49). The diapause induced for 4 months negatively affects reproduction and life span of adults of G. molesta.

Effect of Different Thermal Conditions on Biology and Number of Generations of Palpita forficifera (Lepidoptera: Crambidae)

“…This ecological relationship between insect and plant may provide an adequate microclimate, allowing the pest to survive through critical periods for the development of the species, especially during cold seasons (May through Jul) (temperatures lower than or close to 10 °C). The diapause phenomenon has not yet been verified for P. forficifera, as has been observed in Grapholita molesta Busck (Lepidoptera: Tortricidae) (Silva et al 2014), an important pest of apple and peach orchards in Brazil. However, it is relevant to note that at 15 °C copulation was not observed in lab conditions, indicating that low temperatures are not suitable for mating to occur, and the low temperatures must have interfered in sexual maturity or production of pheromones (Milano et al 2008).…”

Population genomic signatures of the oriental fruit moth related to the Pleistocene climates

“…A previous study found that low genetic polymorphism at the Clk gene may limit adaptation to changing environments as suggested in other species 37 , 38 . It is well known that the oriental fruit moth overwinters by diapause of the last instar larvae 61 . Diapause induction of insects is associated with the circadian clock 62 .…”

Effect of a short-cycle apple tree cultivar on oriental fruit moth (Lepidoptera: Tortricidae) development and larval behavior

“…In apple orchards in Brazil during winter, GM larvae are in diapause (Hickel et al, 2003) or continue their development while feeding on burrknots (Silva et al, 2014;Bisognin et al, 2012). These are undifferentiated structures that contain cyanogenic glycosides, which are toxic to insects at high concentrations (Zagrobelny et al, 2004), causing symptoms associated with larval tissue deterioration (LTD) (Silva et al, 2014).…”

“…In apple orchards in Brazil during winter, GM larvae are in diapause (Hickel et al, 2003) or continue their development while feeding on burrknots (Silva et al, 2014;Bisognin et al, 2012). These are undifferentiated structures that contain cyanogenic glycosides, which are toxic to insects at high concentrations (Zagrobelny et al, 2004), causing symptoms associated with larval tissue deterioration (LTD) (Silva et al, 2014). This type of food influences the biology of GM in relation to fruits (Silva et al, 2014;Bisognin et al, 2012) but allows the perpetuation of the species in winter, when no other preferred sources of food, such as new shoots and fruits, are available.…”