Hemolymph juvenile hormone titers in pupal and adult stages of southwestern corn borer [Diatraea grandiosella (pyralidae)] and relationship with egg development

Most organisms are constantly faced with environmental changes and stressors. In diverse organisms, there is an anticipatory mechanism during development that can program adult phenotypes. The adult phenotype would be adapted to the predicted environment that occurred during organism maturation. However, whether this anticipatory mechanism is present in eusocial species is questionable because eusocial organisms are largely shielded from exogenous conditions by their stable nest environment. In this study, we tested whether food deprivation during development of the honey bee (Apis mellifera), a eusocial insect model, can shift adult phenotypes to better cope with nutritional stress. After subjecting fifth instar worker larvae to short-term starvation, we measured nutrition-related morphology, starvation resistance, physiology, endocrinology and behavior in the adults. We found that the larval starvation caused adult honey bees to become more resilient toward starvation. Moreover, the adult bees were characterized by reduced ovary size, elevated glycogen stores and juvenile hormone (JH) titers, and decreased sugar sensitivity. These changes, in general, can help adult insects survive and reproduce in food-poor environments. Overall, we found for the first time support for an anticipatory mechanism in a eusocial species, the honey bee. Our results suggest that this mechanism may play a role in honey bee queen-worker differentiation and worker division of labor, both of which are related to the responses to nutritional stress.

Section: Jh Measurementmentioning

confidence: 99%

Starvation stress during larval development facilitates an adaptive response in adult worker honey bees (Apis mellifera L.)

Wang

Kaftanoğlu

Brent

et al. 2016

“…The larvae were ground using a glass rod, centrifuged and the supernatant collected. Samples were processed using the GC-MS method as reported elsewhere [(Dolezal et al, 2009) as modified from Shu et al (Shu et al, 1997)]. Purified and derivatized JH was analyzed using a HP 6890 Series GC equipped with a 30mϫ0.25mm Carbowax Econo-Cap GC column (Alltech, Nicholasville, KY, USA) coupled to a HP 5973N inert MSD/DS running in SIM mode.…”

Section: Jh Analysismentioning

confidence: 99%

IRS and TOR nutrient-signaling pathways act via juvenile hormone to influence honey bee caste fate

Mutti

Doležal

Wolschin

et al. 2011

181

155

SUMMARYRegardless of genetic makeup, a female honey bee becomes a queen or worker depending on the food she receives as a larva. For decades, it has been known that nutrition and juvenile hormone (JH) signaling determine the caste fate of the individual bee. However, it is still largely unclear how these factors are connected. To address this question, we suppressed nutrient sensing by RNA interference (RNAi)-mediated gene knockdown of IRS (insulin receptor substrate) and TOR (target of rapamycin) in larvae reared on queen diet. The treatments affected several layers of organismal organization that could play a role in the response to differential nutrition between castes. These include transcript profiles, proteomic patterns, lipid levels, DNA methylation response and morphological features. Most importantly, gene knockdown abolished a JH peak that signals queen development and resulted in a worker phenotype. Application of JH rescued the queen phenotype in either knockdown, which demonstrates that the larval response to JH remains intact and can drive normal developmental plasticity even when IRS or TOR transcript levels are reduced. We discuss our results in the context of other recent findings on honey bee caste and development and propose that IRS is an alternative substrate for the Egfr (epidermal growth factor receptor) in honey bees. Overall, our study describes how the interplay of nutritional and hormonal signals affects many levels of organismal organization to build different phenotypes from identical genotypes. Supplementary material available online at

“…Hormone extraction and purification then followed the same processes utilized in P. californicus queens ) (modified from Shu et al, 1997). JH was extracted from the homogenate using hexane and was then purified via elution through aluminium oxide columns with hexane, 10% ethyl ether-hexane and 30% ethyl ether-hexane (Sigma-Aldrich).…”

Section: Sampling and Hormone Assaysmentioning

confidence: 99%

Worker division of labor and endocrine physiology are associated in the harvester ant,Pogonomyrmex californicus

Doležal

Brent

Hölldobler

et al. 2012

SUMMARYIn Pogonomyrmex californicus harvester ants, an age-associated division of labor occurs in the worker caste, in which young workers perform in-nest tasks and older workers forage for food. Here, we tested whether this behavioral division is age based or age flexible, and whether it coincides with differential expression of systemic hormones with known roles in behavioral regulation. Whole-body content of juvenile hormone (JH) and ecdysteroids was determined in workers from (1) age-typical colonies, in which a typical age structure is maintained and workers transition across behaviors naturally, and (2) single-cohort colonies, which are entirely composed of same-aged workers, facilitating the establishment of age-independent division of labor. Foragers from both colony types had higher JH and lower ecdysteroid content than workers performing in-nest tasks, suggesting that age is not the sole determinant of worker behavior. This association between hormone content and behavior of P. californicus workers is similar to that previously observed in founding queens of this species. Because these hormones are key regulators of development and reproductive behavior, our data are consistent with the reproductive ground plan hypothesis (RGPH), which posits that the reproductive regulatory mechanisms of solitary ancestors were co-opted to regulate worker behavior.