Most wild bees are solitary, but one tiny species of carpenter bees meticulously cares for and nurtures their larvae, which results in significant benefits to the growing bee’s microbiome, development, and health, according to York University researchers.
The maternal care of these carpenter bees (Ceratina calcarata) prevents an overpopulation of dangerous fungus, bacteria, viruses, and parasites in the early stages of development, similar to the good effect human moms may have on their kids.
Without mother care, these growing bees’ pathogen load increased—85% of pathogens were fungal, while 8% were bacteria—which can affect their microbiome, a vital component of bee health, as well as their development, immune system, and gene expression. This can result in alterations in brain and visual development, as well as behavioral disorders.
The most numerous fungus discovered was Aspergillus, which is known to cause stonebrood illness in honey bees, which mummifies the young. In later phases, a lack of care might result in a diminished microbiome, increasing susceptibility to illnesses and resulting in poor overall health.
The researchers examined four developmental phases in the lives of these carpenter bees, beginning with the larval stage in both the presence and absence of mother care.
“There are fitness consequences to these fungal infections.” We’re recording changes in development and disease loads, which is significant since there’s a lot less known about disease loads in wild bees. For the first time, we are emphasizing all of these characteristics,” explains senior author Sandra Rehan, a professor at York’s Faculty of Science.
A nest of a little carpenter bee (ceratina calcarata). Sandra Rehan (York University)
The developmental alterations that occurred as a result of whether genes were expressed or inhibited, upregulated or downregulated, as well as disease burdens, depending on the presence or absence of maternal care, had an impact on the microbiome and bee health.
From spring until late fall, these solitary moms create one nest a year in the pith of dead plant stems, where they give birth and care for their kids. Anything that hinders the mother from caring for her young increases the chance of nest predation and parasitism, including excessive spring and autumn stem trimming, and can have serious effects for their young.
The study, titled “The effects of maternal care on the developmental transcriptome and metatranscriptome of a wild bee,” appears in the journal Communications Biology. Katherine Chau of York University is a postdoctoral fellow at Mitacs Elevate and the Weston Family Foundation Microbiome Initiative.
“We found really striking shifts in the earliest stages, which was surprising because we did not expect that stage to be the most significantly changed,” Chau adds. “When you look at gene expression in these bees, you can see how the smallest misregulation early in development cascades through their entire formation.” It’s all interrelated and demonstrates the importance of mother care in early kid development.”
This study provides metatranscriptomic insights into the influence of maternal care on growing children, as well as a core framework for tracking microbiome development. “It is a complex paper that provides layers of data and shows the power of genomics as a tool,” Rehan adds. “It allows us to record the interactions between the host and the environment.” That, I believe, is the strength of our approach, as well as the new technologies and procedures that we are creating.”
Ceratina calcarata, a little carpenter bee, on a pink blossom. Sandra Rehan (York University)
She also expects that it will provide additional insight into the secret life of bees, as well as their huge variances and commonalities. “Often, people see bees as a monolith, but when you understand the complexity of bees and that there are wild bees and managed bees, people are more likely to care about bee diversity,” Rehan adds.
Mariam Shamekh, a former honors thesis student and a Natural Sciences and Engineering Research Council of Canada (NSERC) Undergrad Student Research Award recipient, and Jesse Huisken, a Ph.D. candidate and an NSERC Postgraduate scholarship holder, are also authors on the article.