We examined the competitive interactions between a native fruit fly species (Anastrepha obliqua Macquart) and the invasive medfly (Ceratitis capitata Wiedemann) when these co‐occur on a shared mango fruit host (Mangifera indica L.). Using mango fruits of distinct levels of ripeness, we investigated both competition among larvae and among adult females for oviposition. We quantified competition by the numbers of eggs laid and the intensity of agonistic interactions between adult females. Interactions between immature fruit flies led to reduced size and number of emerged adults of both species. These impacts were felt more acutely in the native species. Interspecific competition between females led to fewer eggs laid on semi‐ripe fruit by both species, which may be the result of niche overlap associated with oviposition. Intraspecific interactions between A. obliqua individuals led to intense agonistic behaviour, with a concurrent decrease in number of landings on these host fruits. These results suggest that the native species undergoes a partial niche displacement when facing the invasive species. A portion of the fundamental niche of A. obliqua remained unoccupied by the invading C. capitata, which may allow their coexistence under natural conditions.

中文翻译：

---

在寄主芒果（ Mangifera indica ）的侵占中，Ceratitis capitalta 对 Anastrepha obliqua 的竞争相互作用和部分置换

我们研究了本地果蝇物种 (Anastrephaobliqua Macquart) 和侵入性地中海果蝇 (Ceratitis capitalta Wiedemann) 之间的竞争相互作用，当它们共同发生在共享芒果果实宿主 (Mangifera indica L.) 上时。使用不同成熟度的芒果果实，我们调查了幼虫和成年雌虫之间的产卵竞争。我们通过产卵数量和成年雌性之间激动相互作用的强度来量化竞争。未成熟果蝇之间的相互作用导致两个物种成虫的大小和数量减少。这些影响在本地物种中更为明显。雌性之间的种间竞争导致两个物种在半成熟果实上产卵较少，这可能是与产卵相关的生态位重叠的结果。A. obliqua 个体之间的种内相互作用导致强烈的激动行为，同时在这些寄主果实上的着陆次数减少。这些结果表明，本地物种在面对入侵物种时会发生部分生态位位移。A.obliqua 的一部分基本生态位未被入侵的 C.capitata 占据，这可能允许它们在自然条件下共存。