Coexistence and distribution patterns of Anastrepha dentata and Anastrepha pallens (Diptera: Tephritidae) associated with fruits of Sideroxylon celastrinum (Sapotaceae) along an altitudinal gradient in East-central Mexico

We present the first confirmed host-plant association of Anastrepha dentata (Stone) (Diptera: Tephritidae) with Sideroxylon celastrinum (Sapotaceae) and provide new insights into its coexistence and altitudinal segregation with Anastrepha pallens (Coquillett) in central Veracruz, Mexico. Multi-year surveys across elevations ranging from 270 to 720 m revealed consistent partitioning, with A. dentata dominating higher elevations and A. pallens prevailing in lowland areas, while both species co-occurred at intermediate elevations. Laboratory rearing demonstrated a strict one-larva-per-fruit pattern and species-specific differences in fruit selection. Canonical discriminant analysis showed that fruit length (not fruit weight), was the primary morphological trait associated with infestation by A. pallens , a novel pattern not previously documented for this host-fruit fly system. Developmental timing also differed between species, with A. dentata exhibiting slower development at cooler, high-elevation sites and A. pallens developing more rapidly in warm lowland environments. Parasitism was minimal, indicating little parasitoid impact on either fly species. Together, these results highlight the combined influence of environmental filtering, fruit morphological traits, and microclimatic variation in structuring the distribution and coexistence of these species. This work expands the natural history of A. dentata and A. pallens and advances our understanding of ecological differentiation within Neotropical fruit fly communities.