Opossums as opportunistic visitors of chiropterophilous flowers: Interaction between Didelphis albiventris (Marsupialia) and Hymenaea cangaceira (Fabaceae)

Bat-pollinated plants feature open flowers, facilitating easy access to their abundant nectar for various animal groups. The Caatinga, a Brazilian Seasonally Tropical Dry Forest, stands out globally as a hotspot for bat-pollinated plants. This study presents the first documentation of the opossum Didelphis albiventris (Marsupialia) engaging in the consumption of nectar on flowers of Hymenaea cangaceira (Fabaceae), a bat-pollinated tree species within the Caatinga. The observation spanned five nights and occurred unexpectedly during an experiment involving bagged flowers to assess nectar dynamics. Initially, torn bags were discovered containing flowers, which nectar had been consumed. Subsequent nights revealed the opossum actively exploring bagged flowers, likely guided by the fragrant nectar of H. cangaceira, and unmanipulated flowers located in the canopy's upper reaches. Given the opossum's contact with reproductive structures during these visits, it emerges as a potential pollinator. Following this observation, a comprehensive literature review on Didelphis interactions with other plants was conducted, leading to the construction of a meta network. This network unequivocally illustrates that the majority of plants visited by Didelphis indeed have bats as their primary pollinators. Owing to the nocturnal, arboreal and stealthy nature of opossums, documenting their interactions with flowers proves highly challenging. Consequently, our record highlights significant knowledge gaps in comprehending the interplay between opossums and chiropterophilous flowers. These gaps include the under-sampling of this process in the Caatinga, the role of olfactory signalling and the broader consequences of this unique interaction.