Larval temperature variability alters reproduction and population growth in false codling moth Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae)

Publication Type

Journal Article

Journal Name

International Journal of Tropical Insect Science

Publication Date

6-1-2025

Abstract

The false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is a polyphagous insect pest that causes damage to a wide range of important fruit and vegetable crops in sub-Saharan Africa. Although it is an important pest, the effects of temperature amplitudes on the biology of T. leucotreta remain poorly understood. Temperature amplitudes refer to the range between the highest and lowest temperature records within a specific period. This study aimed to investigate the influence of different temperature amplitudes at the larval stage on the development, reproduction, and population growth parameters of T. leucotreta. The larvae were reared at different temperatures amplitudes of 25 °C, 25 ± 2 °C, 25 ± 4 °C, 25 ± 6 °C, 25 ± 8 °C, 25 ± 10 °C, and 25 ± 12 °C, with a mean temperature of 25 °C. The larval temperature amplitudes significantly influenced the development, survival, reproduction, and population growth parameters of T. leucotreta. The wide temperature amplitudes (25 ± 10°C and 25 ± 12 °C) inhibited the development of larva and pupa stages, resulting in longer developmental times. The age-stage-specific survival rate varied, and the survival curves overlapped, indicating different growth rates among individuals. The survival rate of larvae and pupae was highest at 25 °C, followed by 25 ± 2 °C, and it decreased with an increase in temperature amplitudes. Female oviposition gradually increased with an increase in the larval temperature amplitude, with peak oviposition at 25 ± 6 °C (737 eggs per female) and lowest at 25 ± 12 °C (478 eggs per female). The reproductive value showed that the offspring reproduction began earliest in the population obtained from the larvae reared at 25 °C and 25 ± 2 °C, starting at 33 days of age. However, at higher temperature amplitudes, reproduction was slightly delayed. The intrinsic rate of natural increase (rm) decreased from 0.135 at 25 °C to 0.086 at 25 ± 12 °C. Our results could help better understand the influence of temperature amplitude on insect life history and assess the impact of climate change on the distribution and abundance of insect pests.

Keywords

Climate change, Cross-stage, Diurnal temperature range, FCM, Life-history traits, Thermal response

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