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

Wilson, Sara Maxine

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

Description

Title

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

Author(s)

Wilson, Sara Maxine

Issue Date

2022-07-19

Director of Research (if dissertation) or Advisor (if thesis)

Stone, Christopher M

Committee Member(s)

• Ngumbi, Esther
• Allan, Brian F

Department of Study

Entomology

Discipline

Entomology

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Culex pipiens
• Diapause
• Energy Reserves

Abstract

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.

Graduation Semester

2022-08

Type of Resource

Thesis

Copyright and License Information

Copyright 2022 Sara Wilson

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