Location: Pest Management and Biocontrol ResearchTitle: Juvenile hormone III but not 20-hydroxyecdysone regulates the embryonic diapause of aedes albopictus
|BATZ, ZACHARY - Georgetown University|
|MARIAS, MOLLY - Georgetown University|
|SUGIJANTO, JENNIFER - Georgetown University|
|ARMBRUSTER, PETER - Georgetown University|
Submitted to: Frontiers in Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/10/2019
Publication Date: 10/25/2019
Citation: Batz, Z.A., Brent, C.S., Marias, M.R., Sugijanto, J., Armbruster, P.A. 2019. Juvenile hormone III but not 20-hydroxyecdysone regulates the embryonic diapause of aedes albopictus. Frontiers in Physiology. 10. https://doi.org/10.3389/fphys.2019.01352.
Interpretive Summary: Characterizing the linkage between external stimuli and developmental arrest via hormonal signaling remains a major challenge. Elucidating these pathways in a variety of species will provide critical insight for numerous fundamental and applied problems including understanding the molecular and physiological basis of life history evolution, predicting species responses to climate change, and identifying novel targets for pest and vector control. Here, we advance this goal by directly assessing hormone titers in Ae. albopictus, a widely invasive mosquito and an important arbovirus vector. Our results implicate reduced juvenile hormone abundance as the likely regulator of embryonic diapause in this species, and this hypothesis is strongly supported by independent transcriptional and manipulative evidence. Unlike other species, ecdysteroids do not appear to play a role in diapause induction and maintenance. This research is the first direct quantification of hormone abundance during embryonic diapause in any Dipteran species and represents an important step towards clarifying the hormonal regulation of this critical adaptation.
Technical Abstract: Diapause is an alternative developmental trajectory allowing insects to enter dormancy and persist through predictable periods of seasonally-unfavorable conditions. This crucial ecological adaptation defines the geographic and seasonal abundance of many insect pollinators, pests, and vectors. Understanding the hormonal changes by which insects coordinate the perception of external, diapause-inducing cues with the physiological mechanisms that lead to developmental arrest is a long-standing goal in biology. The hormonal regulation of diapause tends to vary by the life stage at which development arrests; for example, diapause is typically regulated by ecdysteroids in larvae and pupae, and by juvenile hormones in adults. However, little is known about the hormonal control of embryonic diapause, particularly in Diptera. To address this fundamental gap, we directly measured 20-hydroxyecdysone (via LC-MS/MS) and juvenile hormone III (via GC-MS) in diapause and non-diapause eggs of the Asian tiger mosquito, Aedes albopictus. While 20-hydroxyecdysone abundance did not differ, diapause eggs had lower juvenile hormone III abundance than non-diapause eggs. These results are corroborated by transcriptional and manipulative evidence suggesting that reduced juvenile hormone III regulates diapause in this medically-important mosquito.