Decoupling the effects of nutrition, age and behavioral caste on honey bee physiology and immunity

Miguel Corona; Belen Branchiccela; Shayne Madella; Yanping Chen; Jay Evans

The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. . https://doi.org/10.1101/667931 doi: bioRxiv preprint 580 are expressed in different tissues and organs including the brain [29, 30], fat bodies [27] and 581 ovaries [84] . Although these studies have revealed the existence of differential tissue-specific 582 responses to nutritional inputs, few tissues and organs have been so far analyzed and it is 583 unknown the contribution of their expression relative to the whole body. Our analysis of ilp1 584 showed that this gene presented behavioral differences in 2-week-old workers from colonies with 585 unrestricted access to pollen, in which foragers had significantly higher levels compared with 586 nurses. Thus, ilp1 expression patterns in the whole-body followed a similar pattern to that 587 reported in isolated brains, but this similarly is restricted to young individuals of colonies not 588 experiencing nutritional stress. The magnitude of the difference between nurses and foragers for 589 the whole body is lower than that observed in brains [29, 30] . This result suggests that in young 590 nurses ilp1 expression is upregulated in other tissues when the colony is not nutritionally stressed. . On the other hand, given the expression differences yet existing between young 595 nurses and foragers from colonies not experiencing pollen deprivation, our results also suggest 596 that under this nutritional condition, ilp1 is predominantly higher expressed in forager's brain 597 compared with other tissues of nurses (e.g., fat body). In addition, nutritional comparison among 598 young foragers indicates that ilp1 expression is reduced by nutritional stress, possibly by 599 inhibiting ilp1 forager's brain expression. In contrast, in older nurses, nutritional stress is 600 associated with increased expression of ilp1. It remains to be addressed the contribution of the 601 brain and other tissues in this response. On the other hand, age comparisons revealed an 602 important age-dependent reduction in its expression in both nutritional conditions. Thus, ilp1 603 follow similar mRNA levels and expression pattern compared to mfe, but with some differences 604 in the strength of the effects of nutrition and age. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available for use under a CC0 license.