Understanding the processes that enable species coexistence has important implications for assessing
how ecological systems will respond to global change. Morphology and functional similarity increase
the potential for competition, and therefore, co-occurring morphologically similar but genetically
unique species are a good model ...
Understanding the processes that enable species coexistence has important implications for assessing
how ecological systems will respond to global change. Morphology and functional similarity increase
the potential for competition, and therefore, co-occurring morphologically similar but genetically
unique species are a good model system for testing coexistence mechanisms. We used DNA
metabarcoding and High Throughput Sequencing to characterise for the first time the trophic ecology
of two recently-described cryptic bat species with parapatric ranges, Myotis escalerai and Myotis
crypticus. We collected faecal samples from allopatric and sympatric regions and from syntopic and
allotopic locations within the sympatric region to describe the diets both taxonomically and
functionally and compare prey consumption with prey availability. The two bat species had highly
similar diets characterised by high arthropod diversity, particularly Lepidoptera, Diptera and Araneae,
and a high proportion of prey that is not volant at night, which points to extensive use of gleaning.
Diet overlap at the prey-item level was lower in syntopic populations, supporting trophic shift under
fine-scale co-occurrence. Furthermore, the diet of M. escalerai had a marginally lower proportion of
not nocturnally volant prey in syntopic populations, suggesting that the shift in diet may be driven by
a change in foraging mode. Our findings suggest that fine-scale coexistence mechanisms can have
implications for maintaining broad-scale diversity patterns. This study highlights the importance of
including both allopatric and sympatric populations and choosing meaningful spatial scales for
detecting ecological patterns. We conclude that a combination of high taxonomic resolution with a
functional approach helps identify patterns of niche shift.