Bats as potential suppressors of multiple agricultural pests: A case study from Madagascar

Abstract

The conversion of natural habitats to agriculture is one of the main drivers of biotic change. Madagascar is no exception and land-use change, mostly driven by slash-and-burn agriculture, is impacting the island's exceptional biodiversity. Although most species are negatively affected by agricultural expansion, some, such as synanthropic bats, are capable of exploring newly available resources and benefit from man-made agricultural ecosystems. As bats are known predators of agricultural pests it seems possible that Malagasy bats may be preferentially foraging within agricultural areas and therefore provide important pest suppression services. To investigate the potential role of bats as pest suppressors, we conducted acoustic surveys of insectivorous bats in and around Ranomafana National Park, Madagascar, during November and December 2015. We surveyed five landcover types: irrigated rice, hillside rice, secondary vegetation, forest fragment and continuous forest. 9,569 bat passes from a regional assemblage of 19 species were recorded. In parallel, we collected faeces from the six most common bat species to detect insect pest species in their diet using DNA metabarcoding. Total bat activity was higher over rice fields when compared to forest and bats belonging to the open space and edge space sonotypes were the most benefited by the conversion of forest to hillside and irrigated rice. Two economically important rice pests were detected in the faecal samples collected-the paddy swarming armyworm Spodoptera mauritia was detected in Mops leucogaster samples while the grass webworm Herpetogramma licarsisalis was detected from Mormopterus jugularis and Miniopterus majori samples. Other crops pests detected included the sugarcane cicada Yanga guttulata, the macadamia nut-borer Thaumatotibia batrachopa and the sober tabby Ericeia inangulata (a pest of citrus fruits). Samples from all bat species also contained reads from important insect disease vectors. In light of our results we argue that Malagasy insectivorous bats have the potential to suppress agricultural pests. It is important to retain and maximise Malagasy Benstead, 2005). However, despite its high level of endemism and species diversity, Madagascar's forests continue to face one of the highest rates of conversion in the world with approximately 1% of the island's forest cover being cleared each year (Rasolofoson et al., 2015; Eklund et al., 2016; Vieilledent et al., 2018). While most Malagasy biodiversity is adversely affected by agriculture-driven habitat modification, some 'winner' species benefit from habitat modification and increase their abundance in agricultural areas. Several of these are insectivorous birds (Martin et al., 2012; Rocha et al., 2015) and bats (López-Baucells et al., 2017b) that through the suppression of agricultural pests can provide valuable ecosystem services to local populations (Karp and Daily 2014; Maas et al. 2015). Rice (Oryza spp.) is one of the most important staple food crops worldwide (Muthayya et al., 2014). It is the main...

From metabarcoding to metaphylogeography: separating the wheat from the chaff

“…This parameter was set for the COI fragment used here after comparing the number of MOTUs obtained at different values and checking that this number remained constant for values of d in the range of 9-13. The value of d = 13 has been previously used in other studies involving the same COI fragment (Mac ıas-Hern andez et al 2018, Kemp et al 2019, Siegenthaler et al 2019). The taxonomic assignment of the MOTU was performed using ecotag (Boyer et al 2016), which uses a local reference database and a phylogenetic tree-based approach (using the NCBI taxonomy) for assigning sequences without a perfect match.…”

Effects of Forest Fragmentation on the Vertical Stratification of Neotropical Bats

“…Powered flight allows bats to explore resources across the multilayered space of tropical rainforests and an increasing number of studies have documented changes in species abundance from ground to subcanopy and canopy levels in both the Neo-and Paleotropics (e.g., [15][16][17][18]). Bats provide vital ecosystem services as seed dispersers, pollinators and arthropod predators [19] and, given the strong preference of several frugivorous species for pioneer plants, promote the regeneration of disturbed areas [20,21]. They are acutely sensitive to human-induced forest disturbances [22] and have extensively been used as an indicator group for evaluating the effects of habitat fragmentation on tropical biota [23,24].The responses of tropical bat assemblages to forest fragmentation are to a large extent species-, ensemble-and habitat-specific (reviewed in [23]).…”

DNA metabarcoding in diet studies: Unveiling ecological aspects in aquatic and terrestrial ecosystems

“…For instance, after an initial description of the dietary habits of the little brown bat Myotis lucifugus based on metabarcoding approaches (Clare et al, ; Clare et al, ), this species was used in comparative dietary studies assessing human influence on feeding habits of bats (Cravens et al, ) and to improve the identification of arthropods in DNA‐based diet studies (Jusino et al, ). Favoring their place as good biological models in the assessment of vertebrates' diets, bat species have distinct feeding and foraging habits, and different ecologic requirements and are widely distributed across a variety of terrestrial ecosystems, even in human‐altered habitats (Kemp et al, ; Long, Kurta, & Clemans, ). Moreover, the possibility to concomitantly explore both the diet of a species and its population structure was recently explored using the common vampire bat Desmodus rotundus as focal species (Bohmann et al, ).…”