Diversity of Bacterial Communities Associated with Solitary Bee Osmia excavata Alfken (Hymenoptera: Megachilidae)

Abstract

Insect-associated microorganisms play important roles in the health and development of insects. This study aimed to investigate the similarities and differences in bacterial community structure and composition between the larval gut of Osmia excavata, nest soil, and brood provision from the nest tube. We sequenced larvae gut and their environments’ microorganisms of O. excavata from four locations based on full-length 16S rRNA gene amplicons. The results showed 156, 280, and 366 bacterial OTUs from gut, brood provision, and nest soil, respectively, and three groups shared 131 bacterial OTUs. In the gut, the top two dominant bacteria were Sodalis praecaptivus (68.99%), Lactobacillus micheneri (17.95%). In the brood provision, the top two dominant bacteria were S. praecaptivus (26.66%), Acinetobacter nectaris (13.05%), and in the nest soil, the two most abundant bacteria were Gaiella occulta (4.33%), Vicinamibacter silvestris (3.88%). There were significant differences in diversity between the brood provision groups and the nest soil groups, respectively. Three of the four locations did not differ for gut microbial diversity. Bacteria similar to other solitary bees also existed in the gut of the larvae. Results indicated when the habitat environments were similar, the bacterial community diversity of the gut of O. excavata was similar, despite significant differences among brood provisions and soils, respectively.

Cold storage alters the fat–trehalose trade‐off, decreases the flight ability, and maintains the high survival rate and flight speed of Osmia excavata (Hymenoptera: Megachilidae)

“…The results of our previous study have shown that the freezing point and supercooling point of O. excavata are both approximately −10 °C (Liu et al. , 2018b); hence, we suggest that the long‐term refrigeration at 0 °C in this study did not interfere with the water balance or induce physiological harm. In recent years, antifreeze proteins, such as heat‐shock proteins, ice nucleator proteins, and lipoproteins, have been identified in many insects; these proteins allow insects to survive in low‐temperature environments (Ouyang & Ge, 2014).…”

“…and reduce the rate of development of Apis mellifera (Zhu et al, 2015;Liu et al, 2021). In recent years, Osmia populations, along with their pollination services, have severely declined, and unsuitable growing conditions are considered the main cause of this decline (Cao et al, 2017;Liu et al, 2018a;Song et al, 2021). However, few studies have investigated the effects of cold storage on Osmia, especially in mature or overwintered bees (Bennett et al, 2013;Campoy et al, 2022).…”

Environmentally acquired gut-associated bacteria are not critical for growth and survival in a solitary bee, Megachile rotundata

“…In the halictid bees Halictus ligatus and Lasioglossum pilosum, Sodalis was absent when Lactobacillus dominated the microbiome at 94% and 9%, respectively (54). Similar trend was also seen in Osmia excavate, where dominance of Sodalis decreased the abundance of A. micheneri and vice-versa (55). In Hymenopterans, Sodalis is maternally inherited and can potentially compromise reproductive compatibility (56).…”

Bee-Associated Beneficial Microbes—Importance for Bees and for Humans

“…Honeybee foragers collect and bring the pollen to the hive (bee-pollen), where it is mixed with glandular secretions, nectar, or honey, processed by symbiont microbes, and becomes bee bread, the naturally fermented pollen that is colonies’ staple food [ 34 ]. Bee bread is a highly nutritious food that contains large bacterial diversity, some of which is crucial for the performance of the fermentation process conducting transformation of pollen (plant material) into a more digestible form for bees, and further contributing not only to their nutritional needs, but providing bioactive metabolites clearly associated with overall hive health, including protection against harmful microbes and contributes to the detoxification processes [ 34 , 35 ]. Different bacterial genera are observed in bee bread, with variation in the relative abundance of dominant taxa in the different layers of the product and types of ecosystems [ 30 ].…”

“…For solitary bees ( Osmia excavate ), the specificity of bacterial community architecture and diversity associated with the gut of larva, characteristics of the nest soil, and brood provision from the nest tube, are factors investigated and pointed to as crucial for the observed significant differences in microbial diversity between brood provision groups and nest soil groups [ 35 ]. Reported observations emphasize the complexity of the microbiota of solitary bees and the relevance of the potential impact that the microbial community of solitary bees can play on their health and physiology [ 35 , 47 ].…”