A study on the diversity and seasonal variations of the moth fauna (Lepidoptera) in the garden of the entomological research laboratory at Wadi El-Natroun, Egypt

Abstract Background Moths play critical ecological roles as herbivores, pollinators, and prey species, while many constitute significant agricultural pests in Egypt. Despite their importance, comprehensive studies on moth diversity, abundance, and seasonal dynamics in Egyptian ecosystems remain limited. This study investigated temporal patterns of moth assemblages in the garden of the Entomological Research Laboratory at Wadi El-Natroun, Faculty of Science, Cairo University, using light traps over one year (March 2023–February 2024). The study site is characterized by a high degree of urbanization and anthropogenic activities in Wadi El-Natroun Depression, within Egypt’s Western Desert. Results A total of 6,546 individuals representing 33 species across seven families were collected. Noctuidae dominated species richness (36.4%) and abundance (70.9%), followed by Crambidae (18.2% and 14.0%, respectively). Three pest species — Spodoptera littoralis (Boisduval), Scrobipalpa portosanctana (Stainton), and Spodoptera exigua (Hübner) — accounted for 30.69% of total captures. Monthly abundance varied substantially (312–819 individuals), peaking in May and December, while species richness (10–21 species) peaked in November. Shannon diversity values (H = 1.90–2.70) indicated moderate diversity, highest in November. Species showed distinct phenological patterns: spring-active ( Caradrina selini (Boisduval), Dysgonia torrida (Guenée)), summer-active ( Helicoverpa armigera (Hübner), Heliothis peltigera (Denis & Schiffermüller)), autumn-winter-active ( Noctua pronuba (Linnaeus), Scopula donovani (Distant)), and year-round species ( Agrotis ipsilon (Hufnagel), Spodoptera exigua (Hübner)). Spearman correlations revealed that abundance was significantly influenced by temperature and humidity; warm-season species showed strong positive temperature correlations (ρ = 0.84–0.91, p < 0.001), while cool-season species showed negative correlations (ρ = −0.83 to − 0.89, p < 0.001). Conclusions The relatively low species richness recorded (33 species) compared to broader regional surveys of Wadi El-Natroun Depression (160 species) is attributable to differences in spatial scale, habitat heterogeneity, and sampling effort, compounded by the urbanized and anthropogenically disturbed nature of the study site. These findings underscore the need for conservation strategies that balance pest management with biodiversity protection in arid Mediterranean-influenced ecosystems.