Effects of temperature on the phenology and fitness traits of Papilio polytes (Lepidoptera: Papilionidae) in Dhaka, Bangladesh

Abstract

Butterflies are very sensitive to temperature changes and are considered important bio-indicators. In the present study, an attempt was made to determine the effects of temperatures (32 °C, 29 °C and 20 °C) on the phenology, fitness traits, feeding, growth and development of Papilio polytes (Lepidoptera: Papilionidae) under laboratory conditions (16L : 8D; RH 78 ± 2) from May 2023 to February 2024. Different larval instars (n = 20 at 20 °C, n = 15 at 29 °C, and n = 15 at 32 °C) were used to evaluate the effects of the selected temperatures. The life cycle was the longest (45.86 ± 1.45 days) at 20 °C. The results reveal temperature-dependent effects on the survival rate of larvae. The mortality rate was significantly higher at 20 °C (F = 46.801; df = 2; P = 0.0000083). Egg hatchability (n = 13 at 20 °C, n = 15 at 29 °C and n = 27 at 32 °C) significantly varied across the three rearing temperatures (χ² = 10.575; df = 2; P = 0.0064). The relative hatchability of eggs was the highest at 32 °C (n = 27) and the lowest at 20 °C (n = 13). Food consumption did not vary significantly across the three rearing temperatures (H = 4.488; df = 2; P = 0.1060), and faecal production of larvae was not significantly affected either (F = 0.896; df = 2; P = 0.414). The results indicate better performance of P polytes under warmer temperatures.

Dhaka Univ. J. Biol. Sci. 35(2), 159-178, 2026 (July)