The floral bat lure dimethyl disulphide does not attract the palaeotropical Dawn bat
In the neotropics, dimethyl disulphide (DMDS) is innately attractive to flower-visiting bats, and acts as a powerful bat lure in the scent bouquets of many bat-pollinated flowers. At first, DMDS appeared to be part of a general bat pollination syndrome. However, DMDS is absent in many bat-pollinated flowers of West Africa, and it is unclear whether palaeotropical flower-visiting bats are also attracted to it. Furthermore, DMDS was previously observed in neotropical, but not palaeotropical, populations of Ceiba pentandra (Malvaceae, Bombacoideae). We tested for an attraction to DMDS in the most common flower-visiting bat in Thailand, the dawn bat Eonycteris spelaea. We gave bats choices of Ceiba pentandra flowers, where one random flower was scented with DMDS. Rather than preferring the DMDS-treated flower, 21 of 22 bats chose an untreated flower, showing no attraction to DMDS. Alongside past evidence, this result suggests that the role of DMDS in bat pollination syndromes may result from an adaptive convergence that is limited to the neotropics. This hypothesis could be tested through comparative studies of (1) attraction across bats, (2) floral DMDS presence across bat-pollinated plants in Asia, and (3) floral DMDS measures across New and Old World populations of Ceiba pentandra.
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