Short-Term Effects of El Niño (2023–2024 ENSO) Drought on Predation Patterns of Lepidopteran Prey in an Urban-Agricultural Ecosystems

Abstract

El Niño events can significantly disrupt ecosystem dynamics by altering species distribution, population size, and food web interactions, often leading to biodiversity losses and imbalances in ecological relationships. Although an understanding of El Niño-associated climate and weather changes is critical, their impact on ecological interactions in the tropics remains understudied. We investigated differences in the predation rate of lepidopteran larvae across El Niño phases within an urban-agricultural landscape in Southcentral Mindanao, the Philippines. Our results demonstrate notable variations throughout the El Niño phases. Predation rates were considerably higher in the pre-El Niño phase (mean ± SD = 18.24% ± 13.48%) than during the peak of the El Niño phase (mean ± SD = 6.41% ± 10.20%) and showed a slight, yet statistically insignificant, rise in the post-El Niño phase (mean = 9.48% ± 17.66%). Although predation by arthropods on herbivorous preys remained predominant during all periods, vertebrate predation was related to the warmer and drier conditions of El Niño associated with the 2023 ENSO. Our study provides initial insights into how El Niño events shape prey–predator relationships and sustain key ecological functions through species interactions, laying a crucial foundation for future research on the ecological impacts of El Niño droughts in tropical agro-urban systems. We highlight the importance of considering climate variability in predator–prey dynamics and recommend future studies on long-term recovery, habitat restoration, and climate-adaptive strategies to strengthen ecosystem resilience.