Implications of pre-diapause timing on Culex pipiens energetic reserve acquisition and overwintering success

Preparation for overwintering, prediapause, in temperate zones marks a unique ecological and physiological challenge for the West Nile vector Culex pipiens. Prediapause involves a shift from host-seeking to nectar gluttony in diapausing females to build lipid reserves. An open question is how female Cx. pipiens should resolve the trade-off between the time needed for resource acquisition and the length of time they need to survive to overwinter. To test this, Cx. pipiens were reared under early (18℃) and late (15℃) season diapause-inducing conditions. Upon adult emergence, females were placed in cages and provided ad libitum access to water and a 10% honey solution for 1 or 4 weeks. A simulated overwintering study using temperature-controlled incubators was performed, with conditions mimicking average winter temperatures in overwintering hibernacula (4°C), and survival was recorded daily. Energetic reserves, glucose, glycogen, lipids, and protein were measured for a subset of females at the onset of, and eight weeks into the diapause period. Longer feeding periods resulted in significantly better survival outcomes. Lower rearing temperature also resulted in better survival outcomes, though the impact was not found to be significant. Both higher larval rearing temperature and longer feeding duration resulted in significantly more lipids, glycogen, and protein reserves available at the onset of winter. Initial energetic reserves were greatest under early season conditions (18 ºC, 4 weeks feeding) for glycogen, protein, and lipids. Understanding the time needed to build energetic reserves provides insight into the ability of Cx. pipiens to adapt to changing winter temperatures and has implications for transmission of West Nile virus during the fall season. Understanding the role resource acquisition time and rearing temperature have on diapause success, and the timing of diapause entry is important for predicting and understanding how Cx. pipiens will respond to changing temperatures that result from climate change.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Entomology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Wilson, Sara Maxine

Contributors dc:contributor

• Stone, Christopher M
• Ngumbi, Esther
• Allan, Brian F

• Culex pipiens
• Diapause
• Energy Reserves

Statement dc:rights

• Copyright 2022 Sara Wilson

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/115953

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F115953