Diversity and Baits Preference of Flower Flies (Diptera: Syrphidae) Collected Using Van Someren-Rydon Traps in the Colombian Andean-Amazon Piedmont During Two Rainy Seasons

Thirty percent of the flower flies (Diptera: Syrphidae) diversity is concentrated in the Neotropics, with few studies in the Amazonian rainforests. We evaluated diversity, phenology and bait preference of syrphids in three lowland habitats (FE = Forest Edge, DSF = Dense Secondary Forest and AFS = Agroforestry System) in La Avispa Nature and Ecotourism Reserve in Caquetá, Colombia, during two rainy seasons (high rainfall intensity, HIR and low rainfall intensity, LIR). Adults were collected using Van Someren-Rydon traps (VSRTs) baited with fermented fruit, decomposed shrimp or decomposed fish. We estimated alpha and beta diversity components within and between habitats. Phenology was compared between rainy seasons. A total of 1,379 syrphids specimens were collected, belonging to 59 species (13 genera). DSF had the highest abundance and richness (n = 812; 43 species). Syrphid abundance was 8.9 times higher (n = 1.240) during HIR, while richness was 1.8 times higher (68 species) than LIR. Copestylum was the most abundant and diverse genus (n = 1,225; 88.8% of all specimens collected). The VSRTs showed high sampling completeness (≥ 90%), suggesting that this methodology is useful and effective for rapid Syrphids inventories. Species replacement was the dominant component of beta diversity, indicating that each habitat contributes with unique species, providing functions for sustainability and ecosystem balance, where connectivity is essential to ensure the provision of ecosystem services in undergoing ecological restoration areas, such as the tropical rainforest studied here.