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Metabolic rates in harvestmen (Arachnida, Opiliones): the influence of running activity
Author(s) -
Schmitz Anke
Publication year - 2005
Publication title -
physiological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 57
eISSN - 1365-3032
pISSN - 0307-6962
DOI - 10.1111/j.0307-6962.2005.00434.x
Subject(s) - opiliones , respiratory quotient , biology , zoology , metabolic rate , carbon dioxide , treadmill , ecology , endocrinology , physiology
Abstract. Metabolic rates of adult Lophopilio palpinalis (Herbst, 1799) (Arachnida, Opiliones, Phalangioidea) and Paranemastoma quadripunctatum (Perty, 1833) (Arachnida, Opiliones, Troguloidea) are measured during rest and activity. Carbon dioxide release during rest is continuous in both species. Mean values at 20 °C are 4.2 µL min −1 g −1 for the males of P. quadripunctatum , 4.1 µL min −1 g −1 for the males of L. palpinalis and 4.7 µL min −1 g −1 for the females of L. palpinalis , thus being significantly higher in the egg‐producing females. In L. palpinalis, respiratory quotient at rest is 0.84. Spontaneous walking activity with speeds of 15–30 cm min −1 raises the metabolic rate by up to three‐fold in both species. Lophopilio palpinalis is made to undertake constant running on a treadmill with speeds of 60, 72 and 96 cm min −1 . Enforced activity causes the animals to raise their metabolic rates by up to five‐fold above resting rates. Animals reach a steady state of CO 2 release on the treadmill and show a fast t 1/2 on‐response, indicating aerobic exercise. The minimum cost of locomotion is determined to be 2.5 × 10 −3 J cm −1 g −1 , thus fitting the predicted values for terrestrial locomotion.