Mosquito Microbiome Diversity Varies Along a Landscape-Scale Moisture Gradient

Abstract

Microorganisms live in close association with metazoan hosts and form symbiotic microbiotas that modulate host biology. Although the function of host-associated microbiomes may change with composition, hosts within a population can exhibit high turnover in microbiome composition among individuals. However, environmental drivers of this variation are inadequately described. Here, we test the hypothesis that this diversity among the microbiomes of Aedes albopictus (a mosquito disease vector) is associated with the local climate and land-use patterns on the high Pacific island of O 'ahu, Hawai 'i. Our principal finding demonstrates that the relative abundance of several bacterial symbionts in the Ae. albopictus microbiome varies in response to a landscape-scale moisture gradient, resulting in the turnover of the mosquito microbiome composition across the landscape. However, we find no evidence that mosquito microbiome diversity is tied to an index of urbanization. This result has implications toward understanding the assembly of host-associated microbiomes, especially during an era of rampant global climate change.

Cryopreservation of mosquito microbiota for use in microcosm experiments

“…We next validated our isolation and cryopreservation approach using microbiota derived from water collected from a naturally occurring larval habitat in the field. As expected, the bacterial community present in this habitat was comprised of a substantially higher diversity of ~1,000 unique taxa, although these taxa were dominated by members of the same phyla (Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria) detected in laboratory rearing pans and commonly detected in field-collected mosquitoes (5,51,52,(56)(57)(58)(59)(60)(61)(62)(84)(85)(86)(87)(88)(89)(90)(91)(97)(98)(99)(100)(101)(102). Recovery of field-derived taxa in experimental microcosms generated using cryopreserved material from the same habitat was also overall much lower than what we observed in microcosms generated using cryopreserved stocks of lab-derived microbiota, although the taxa lost or significantly reduced in microcosms generated using cryopreserved material were consistent with those lost or significantly reduced in microcosms generated using fresh material-strongly suggesting that the observed shifts in alpha and beta diversity in microcosms were not the result of cryopreservation but rather the inability of many field-derived taxa to thrive under conventional mosquito rearing conditions in the laboratory.…”

A cryopreservation method to recover laboratory- and field-derived bacterial communities from mosquito larval habitats

“…We next validated our isolation and cryopreservation approach using microbiota derived from water collected from a naturally occurring larval habitat in the field. As expected, the bacterial community present in this habitat was comprised of a substantially higher diversity of ~1,000 unique taxa, although these taxa were dominated by members of the same phyla (Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria) detected in laboratory rearing pans and commonly detected in field-collected mosquitoes [2,10,11,[15][16][17][18][19][42][43][44][45][46][47][48][49][60][61][62][63][64][65]. Recovery of field-derived taxa in experimental microcosms generated using cryopreserved material from the same habitat was also overall much lower than what we observed in microcosms generated using cryopreserved stocks of lab-derived microbiota, although the taxa lost or significantly reduced in microcosms generated using cryopreserved material were consistent with those lost or significantly reduced in microcosms generated using fresh material-strongly suggesting that the observed shifts in alpha and beta diversity in microcosms were not the result of cryopreservation but rather the inability of many field-derived taxa to thrive under conventional mosquito rearing conditions in the laboratory.…”

“…However, the immense diversity and variability of the PLOS NEGLECTED TROPICAL DISEASES microbiota within and between different populations of mosquitoes in the laboratory and field have made studying mosquito-microbe interactions-and identifying bacteria that reduce the vectorial capacity of mosquitoes-a formidable challenge [1]. As in other animals, numerous factors have the potential to shape variation in mosquito microbiota and therefore variation in mosquito phenotypes, including the microbiota present in the aquatic environment in which larvae develop, environmental conditions (e.g., diet, temperature), and host genetics [2,3,10,11,[15][16][17][18][19][42][43][44][45][46][47][48][49][50]. However, while experiments with mosquitoes are commonly conducted using genetically identical individuals under highly controlled environmental conditions, tools to standardize the microbiota present in the larval rearing environment are comparatively limited [3,13,[51][52][53][54].…”

Adapting to climate with limited genetic diversity: Nucleotide,DNAmethylation and microbiome variation among populations of the social spiderStegodyphus dumicola

“…This association is driven by 10 ASVs from different taxonomic groups that correlate strongly and/or significantly with aspects of precipitation (Figure S17 ). An effect of precipitation‐related variables has also been found in mosquitoes, where the gut microbiome changes along a landscape–moisture gradient (Medeiros et al, 2021 ), and exposure to altered humidity has been shown to change the microbiome in mice (Yin et al, 2022 ). However, our association study cannot discern whether symbiont abundance is shaped directly by humidity irrespective of the host or indirectly by the host as a response to humidity.…”