Temporal shifts and niche overlapping in <Emphasis Type="Italic">Copestylum</Emphasis> (Diptera,Syrphidae) communities reared in cactus species in a central Mexican scrubland

Semiarid scrubland communities are highly dynamic in terms of their species composition, abundance, and functioning, given the drastic changes in climate among seasons. Spatiotemporal patterns of saprophagous Copestylum (Diptera: Syrphidae) communities in different cactus species richness have not yet been studied, although seasonal changes and plant species richness have been shown to strongly impact the diversity and distribution of many insect communities in scrublands. We analyzed the impact of seasonality and of habitat type (disturbed and undisturbed) on Copestylum communities reared from cactus species at the Barranca de Metztitlán Biosphere Reserve, in central Mexico, by comparing their community structure between seasons and habitats, and assessing the contribution of diversity components for the total diversity of this genus. We also measured patterns of temporal niche overlap among hoverfly species considering their breeding medium. Seasonal variation influenced Copestylum community composition most significantly. Species richness and abundance of Copestylum were higher in the rainy season. Additive partitioning of diversity showed that the main component for species richness is beta diversity between seasons. We detected high niche overlap during the dry season and low overlap during the rainy season. This study provides evidence of temporal shifts in xeric hoverfly communities and suggests that the Copestylum species partition resources over time.