Pollination implications of the diverse diet of tropical nectar-feeding bats roosting in an urban cave

Abstract

BackgroundIntense landscaping often alters the plant composition in urban areas. Knowing which plant species that pollinators are visiting in urban areas is necessary for understanding how landscaping impacts biodiversity and associated ecosystem services. The cave nectar bat, Eonycteris spelaea, is an important pollinator for many plants and is often recorded in human-dominated habitats. Previous studies of the diet of E. spelaea relied on morphological identification of pollen grains found in faeces and on the body of bats and by necessity disregarded other forms of digested plant material present in the faeces (i.e., plant juice and remnants). The main objective of this study was to examine the diet of the nectarivorous bat, E. spelaea, roosting in an urban cave at Batu Caves, Peninsular Malaysia by identifying the plant material present in the faeces of bats using DNA metabarcoding.MethodsFaeces were collected under the roost of E. spelaea once a week from December 2015 to March 2016. Plant DNA was extracted from the faeces, Polymerase chain reaction (PCR) amplified at ITS2 and rbcL regions and mass sequenced. The resultant plant operational taxonomic units were searched against NCBI GenBank for identification.ResultsA total of 55 species of plants were detected from faeces of E. spelaea including Artocarpus heterophyllus, Duabanga grandiflora and Musa spp. which are likely to be important food resources for the cave nectar bat.DiscussionMany native plant species that had not been reported in previous dietary studies of E. spelaea were detected in this study including Bauhinia strychnoidea and Urophyllum leucophlaeum, suggesting that E. spelaea remains a crucial pollinator for these plants even in highly disturbed habitats. The detection of many introduced plant species in the bat faeces indicates that E. spelaea are exploiting them, particularly Xanthostemon chrysanthus, as food resources in urban area. Commercial food crops were detected from all of the faecal samples, suggesting that E. spelaea feed predominantly on the crops particularly jackfruit and banana and play a significant role in pollination of economically important plants. Ferns and figs were also detected in the faeces of E. spelaea suggesting future research avenues to determine whether the ‘specialised nectarivorous’ E. spelaea feed opportunistically on other parts of plants.

A global review of urban pollinators and implications for maintaining pollination services in tropical cities

“…However, it also appears that most of the bee diversity in cities is due to generalist bee species that have flexible diets and nesting habits, which stresses the importance of maintaining natural habitats for rare and specialist species. While we have less data on the effects of urbanization on vertebrate pollinators, the few studies that exist also suggest that cities can support generalist species that are tolerant of human development and activity, if their dietary and nesting or roosting requirements are met (Pauw and Louw 2012;Lim et al 2018, Diniz et al 2019Maruyama et al 2019).…”

“…However, the lack of more studies clearly impairs any generalizations on how urbanization affects bat pollination, and relevant factors may include roost availability, and light pollution among others (Diniz et al 2019;Sritongchuay et al 2019). Roosting site availability may be especially relevant, as a study from Peninsular Malaysia found a diverse number of plant species associated with the cave nectar bat, Eonycteris spelaea (Pteropodidae), inhabiting an urban cave (Lim et al 2018). Another limiting factor may be the lack of nightblooming plant species in cities since urban landscaping tends to favor showy day-blooming species (Loram et al 2008).…”

Small Pteropodid Bats are Important Pollinators of Durian in Terengganu, Malaysia

“…), Indian trumpet (Oroxylum indicum), kapok tree (Ceiba pentandra), bitter bean (Parkia speciosa), and mangrove apples (Sonneratia spp.) (Acharya et al, 2015;Bumrungsri et al, 2013;Lim et al, 2018;Nor Zalipah et al, 2016;Nuevo-Diego et al, 2019;Stewart & Dudash, 2017). Of these, durian was a vital cash crop for both countries.…”

Diversity of bats in three selected forest types in Peninsular Malaysia

“…According to Struebig et al (2010), Old World fruit bats exhibit dispersal capabilities and generalist feeding habits. Eonycteris spleae (Dobson, 1871), a long-tongued fruit bat that is widely distributed in Southeast Asia remains an important pollinator of commercial food crops such as durian (Lim, 2018). Acharya et al (2015) recorded that this species travelled a long distance to foraging areas with durian, moving one-way between flowering patches of durian.…”