First published online January 8, 2007
Journal of Experimental Biology 210, 217-226 (2007)
Published by The Company of Biologists 2007
doi: 10.1242/jeb.02630
Suppression of water loss during adult diapause in the northern house mosquito, Culex pipiens
Joshua B. Benoit* and
David L. Denlinger
The Ohio State University, Department of Entomology, 318 W 12th
Avenue, Columbus, OH 43210, USA

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Fig. 1. Net water loss rates in females of Culex pipiens reared under
diapausing (D18) and nondiapausing conditions (ND25; ND18) at 0.00
av. The slope of the regression through the points
represents the water loss in % h-1. Mt is the
mass at any time t and M0 is the initial water
mass. Values are means ± s.e.m. of 60 mosquitoes. ND25, mosquitoes
reared under a nondiapausing photoperiod (15 h:9 h, L:D) at 25°C; ND18,
mosquitoes reared under a nondiapausing photoperiod at 18°C; D18,
mosquitoes reared under a diapausing photoperiod (9 h:15 h, L:D) at
18°C.
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Fig. 2. Water loss rates in females of Culex pipiens over a prolonged
period. Each point represents water loss determined as in
Fig. 1. ND25, mosquitoes reared
under a nondiapausing photoperiod (15 h:9 h, L:D) at 25°C; ND18,
mosquitoes reared under a nondiapausing photoperiod at 18°C; D18,
mosquitoes reared under a diapausing photoperiod (9 h:15 h, L:D) at 18°C.
D18 to ND25 at 40 days indicates the mosquitoes were moved from diapausing
(D18) to nondiapausing (ND25) conditions after 40 days, to break diapause.
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Fig. 3. Water vapor exchange at different vapor activities in females of Culex
pipiens. For each point, the vapor exchange was determined as in
Fig. 1. ND25, mosquitoes reared
under a nondiapausing photoperiod (15 h:9 h, L:D) at 25°C; ND18,
mosquitoes reared under a nondiapausing photoperiod at 18°C; D18,
mosquitoes reared under a diapausing photoperiod (9 h:15 h, L:D) at
18°C.
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Fig. 4. Water balance characteristics of Culex pipiens females collected
at monthly intervals from the field in Columbus, Ohio. WLR, water loss rate (%
h-1); Md, dry mass (mg);
Mw, water mass (mg); Mi, initial mass
(mg). Values are means ± s.e.m. of 30 mosquitoes.
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Fig. 5. Polyol and sugar content of nondiapausing and diapausing adult females of
Culex pipiens. (A) Sorbitol; (B) glycerol; (C) trehalose; (D) total
sugars. Closed squares, ND25 mosquitoes, reared under a nondiapausing
photoperiod (15 h:9 h, L:D) at 25°C; open squares, ND18 mosquitoes, reared
under a nondiapausing photoperiod at 18°C; closed diamonds, D18
mosquitoes, reared under a diapausing photoperiod (9 h:15 h, L:D) at 18°C;
open diamonds, D18 to ND25 at 40 days. Values are means ± s.e.m. of 10
replicates of five individuals each. All error bars are smaller than the
symbols.
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Fig. 6. Amount of cuticular hydrocarbons extracted from nondiapausing and
diapausing females of Culex pipiens. ND25, mosquitoes reared under a
nondiapausing photoperiod (15 h:9 h, L:D) at 25°C; ND18, mosquitoes reared
under a nondiapausing photoperiod at 18°C; D18, mosquitoes reared under a
diapausing photoperiod (9 h:15 h, L:D) at 18°C; D18 to ND25 at 40 days,
indicates the mosquitoes were moved from diapausing (D18) to nondiapausing
(ND25) conditions after 40 days, to break diapause. Values are means ±
s.e.m. of 10 replicates of five mosquitoes each.
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Fig. 7. Proportional reduction of internal lipid reserves in nondiapausing and
diapausing females of Culex pipiens. ND25, mosquitoes reared under a
nondiapausing photoperiod (15 h:9 h, L:D) at 25°C; ND18, mosquitoes reared
under a nondiapausing photoperiod at 18°C; D18, mosquitoes reared under a
diapausing photoperiod (9 h:15 h, L:D) at 18°C. Values are means ±
s.e.m. of 10 replicates of five mosquitoes each.
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© The Company of Biologists Ltd 2007