ORIGINAL RESEARCH ARTICLE Temperature impacts on the eggplant shoot and fruit borer Leucinodes orbonalis: a life table approach Tarikul Islam 1 & A.H.M. Roknuzzaman 1,2 & Kamrul Hassan 3 & Mohammad Shaef Ullah 1,2 Received: 30 May 2019 /Accepted: 2 December 2019 /Published online: 9 December 2019 # African Association of Insect Scientists 2019 Abstract The eggplant shoot and fruit borer (ESFB), Leucinodes orbonalis Guenee (Lepidoptera: Pyralidae) is a notorious insect pest that causes havoc across all eggplant cultivation areas in Bangladesh. Remarkably, its relationship with environmental factors such as temperature is not clearly defined. We measured the effects of a range of temperatures (22, 24, 26, 28, and 30 °C) on the population growth parameters of ESFB under laboratory conditions (60 ± 5% relative humidity and 16 L:8 D photoperiod), developing an age-stage, two-sex life table. Results indicate that temperature significantly reduced development times and adult total lifespan and affected ESFB life table parameters (P < 0.05). Specifically, the egg hatching time reduced from 5 days at 22 °C to 3 days at 30 °C, while larval and pupal duration reduced from 12 to 8 days and 10 to 7 days respectively. Thus, the generation time (T) was longer (29 days) at 22 °C and shorter (22 days) at 30 °C; meanwhile, the highest fecundity (61 eggs per female) was recorded at 28 °C and the net reproduction rate (R o ) was higher at 24–30 °C, being (18–24) offspring/individual. Consequently, the ESFB population reared at 28 °C and 30 °C had higher finite rates (λ = 1.15 and 1.14 respectively) and intrinsic rates of natural increase (r = 0.14 and 0.13 respectively), testifying the most suitable temperatures for their growth and reproduction. Our findings contribute to understanding ESFB bionomics and occurrences, and thus, might enhance implemented management strategies, particularly in developing pesticide application schedules. Keywords Brinjal shoot and fruit borer . Thermal ecology . Growth parameters . Reproductive biology . Integrated pest management Introduction Global climate has been changing; the surface temperature was raised by more than 0.7 °C over the past century (Hansen et al. 2010). These shifts in temperature impact crit- ical insect life processes such as survival, development rates, population dynamics, seasonal occurrence, and geographical distribution (Bale et al. 2002; Dixon et al. 2009; Amarasekare and Sifuentes 2012; Ullah and Lim 2015). The ideal range of environmental temperature permits optimal growth rate and reproduction of insects, whereas temperatures beyond this have hostile effects (Dixon et al. 2009). Hence, a clearer un- derstanding of temperature roles on insect life stages is essen- tial for predicting their population growth rate and distribution limits (Bale et al. 2002). Moreover, knowledge on how ecto- thermic insects, such as the eggplant shoot and borer (ESFB), adjust their development and reproduction to different envi- ronmental temperatures facilitate their management by fore- casting peak development time, reproduction rate, hibernation and migration (Bale et al. 2002, Golizadeh et al. 2009, Qin et al. 2018). ESFB, Leucinodes orbonalis Guenee (Lepidoptera: Pyralidae) is the key pest of eggplant (Solanum melongena L.) in tropical and subtropical Asia, including Bangladesh, and consequently, one of the major impediments to eggplant production (Srinivasan 2008; CABI 2018). Being an internal feeder, the larvae bore into tender shoots during vegetative growth, subsequently attacking flowers and fruits * Tarikul Islam tarikul.entom@bau.edu.bd 1 Department of Entomology, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh 2 Laboratory of Applied Entomology and Acarology, Department of Entomology, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh 3 Department of Entomology, Sylhet Agricultural University, Sylhet, Bangladesh International Journal of Tropical Insect Science (2020) 40:351–360 https://doi.org/10.1007/s42690-019-00086-7