Effects of cold exposure on Tenebrio molitor (Coleoptera: Tenebrionidae) pupal period, proportion of adult emergence, weight and deformation percentage

Abstract

Low temperatures affect many life history traits of insects. The purpose of this study was to assess the effects of duration of cold exposure on the length of Tenebrio molitor’s pupal period, proportion of adult emergence, adult weight and proportion of deformed adults. The trials were conducted in a laboratory in constant conditions with wheat flour and whole-wheat flour meal were used as food. Cold-exposed groups were achieved by exposing pupae taken on the first day after pupation for 1, 3, 5, 10 and 15 days at +4 °C. The results showed that as the period of cold increased, pupal period extended and proportion of deformed adults increased whereas there were no or less straightforward effects on adult weights and proportion of emerged adults, respectively

Effects of cold storage on the developmental biology of Tenebrio molitor L., 1758 (Coleoptera: Tenebrionidae) at different larval stages

“…In other words, it is evident from this study that larvae kept in cold are more resistant than those kept in the pupal stage (Paul et al, 2017). According to Sönmez & Koç (2019), these differences in the proportion of adult emergence and adult emergence time could indicate a positive correlation between the lipid content stored by the larvae in their bodies and their tolerance to low temperatures (Chown & Gaston, 2010;Mitchella et al, 2017). Especially the proportion of adult emergence of the large larvae was higher than others (for example, when 5 d cold storage, small, medium and large larvae were compared).…”

“…In the study of Sönmez & Koç (2019), it was determined that the adult emergence times were prolonged as the time of cold exposure of the pupae increased. The proportion of deformation in emerged adults increased with duration of cold exposure.…”

“…Previously Sönmez & Koç (2019) determined that as exposure of T. molitor pupae to low temperature increases, the pupal period and deformation rates increase. It is known that resistance to low temperatures is lower for larvae than for pupae (Punzo & Mutchmor, 1980).…”

Farmed Yellow Mealworm (Tenebrio molitor; Coleoptera: Tenebrionidae) Welfare: Species-Specific Recommendations for a Global Industry

“…Cold storage of pupae at 4 ℃ for 15 days increased mortality (75%) and adult deformity (nearly 70%), compared to only 1 day (Sömnez and Koç, 2019). Similarly, increasing the amount of time larvae were in cold storage at 4 ℃ increased mortality and adult deformation rates, with especially dramatic effects for young larvae (Sömnez, 2021).…”

The Effect of Temperature and Nutrient on Developmental Biology and Physiology of Stored-Product Species of Coleoptera

“…Dupuis et al [44] determined that the mortality rate of A. obtectus larvae, pupae and adults was 50% from the 6th day at 0 ºC 1st and 2nd stage larvae live for 4 h at -10 ºC, 6 h for larvae and pupae at other stages, and 16 h at -22 ºC. Sönmez and Koç [47] determined that the longer the storage time at +4 °C, the longer the pupal time and the percentage of deformation of T. molitor.…”