Locomotor and energetic consequences of behavioral thermoregulation in the sanguivorous leech Hirudo verbana.
Medicinal leeches (Hirudo verbana) thermoregulate with respect to their sanguivorous feeding behavior. Immediate postprandial preferences are for warmer than their initial acclimation temperature (Ta, 21°C, Petersen et al. 2011), while unfed leeches have a lower preferred temperature (Tpref, 12.5°C). This may reduce energy expenditure and defer starvation if feeding opportunities are limited. Energetic benefits may have an associated cost if low temperatures reduce mobility and the ability to locate further hosts. These costs could be limited if mobility is unimpaired at low temperatures, or if acclimation can restore locomotor performance to the levels at Ta. The transition from Tato the unfed Tprefsignificantly reduced speed and propulsive cycle frequency during swimming, and extension and retraction rates during crawling. Aerobic metabolic rate was also reduced from 0.20±0.03Wkg-1at Tato 0.10±0.03Wkg-1at Tpref. The Q10values of 1.7-2.9 for energetic and swimming parameters indicate a substantial temperature effect, although part of the decline in swimming performance can be attributed to temperature-related changes in water viscosity. 6 weeks at Taresulted in no detectable acclimation in locomotor performance or aerobic metabolism. The energetic savings associated with a lower Tprefin unfed leeches effectively doubled the estimated time until depletion of energy reserves. Given that some mobility is still retained at Tpref, and that acclimation is in itself costly, the energetic benefits of selecting cooler temperatures between feedings may outweigh the costs associated with reduced locomotor performance.
Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA 02481, USA.
Amanda C
AC
Hitchcock
Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA 02481, USA.
Erin M
EM
Connolly
Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA 02481, USA.
Karin
K
Darakananda
Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA 02481, USA.
Janet W
JW
Jeong
Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA 02481, USA.
Arbor J L
AJ
Quist
Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA 02481, USA.
Allison B
AB
Robbins
Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA 02481, USA. Electronic address: dellerby@wellesley.edu.
David J
DJ
Ellerby
D000064:Acclimatization; D000818:Animals; D001833:Body Temperature Regulation; D003080:Cold Temperature; D004734:Energy Metabolism; D005247:Feeding Behavior; D047709:Hirudo medicinalis / Q000502:physiology*; D008124:Locomotion; D013550:Swimming
Acclimation; Behavioral thermoregulation; Hirudo verbana; Locomotion