2Department of Tropical Parasitology, Medical University of Gdansk, 81-519 Gdynia, Poland
3Department of Zoology, Animal Ecology & Wildlife Management, Faculty of Biology and Animal Breeding, University of Life Sciences in Lublin, 20-950 Lublin, Poland
4Department of Botany and Mycology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Sklodowska University, 20-033 Lublin, Poland
5Institute of Nature Conservation, Polish Academy of Sciences, 31-120 Cracow, Poland
6Zoological Museum/Laboratory, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Sklodowska University, 20-033 Lublin, Poland
7Department of Tourism and Recreation, Faculty of Agrobioengineering, University of Life Sciences in Lublin, 20-950 Lublin, Poland
* To whom correspondence should be addressed.
Received May 30, 2018; Revised November 27, 2018; Accepted November 27, 2018
Active skeletal muscles produce lactate. H+ is generated during lactate neutralization in the Cori cycle, which leads to muscle acidosis and soreness (the so-called Delayed Onset Muscle Soreness, DOMS) in vertebrates. The aim of the study was to determine the activities/concentrations of compounds involved in the Cori cycle in worker and forager bees. Muscles, fat bodies, and hemolymph from 1- and 14-day-old workers and foragers were collected and assayed for the protein, lactate, glucose, NAD+, and NADH concentrations and lactate dehydrogenase (LDH) activity. Both lactate concentration and LDH activity in the hemolymph, muscles, and fat bodies increased with age. The concentrations of NAD+ and NADH in the tissues decreased with ageing/senescence, whereas protein concentrations increased until day 14 of bee’s life and then decreased in foragers. The concentration of glucose decreased in the hemolymph and muscles and increased in the fat bodies. Elevated lactate concentrations in foragers may indicate transition from the aerobic to the anaerobic phase and development of metabolic acidosis that may eventually lead to muscle damage/soreness and shorter lifespan. When analyzing flight dynamics, load mass, and bee behavior, changes in the concentrations of Cori cycle compounds should be taken into account.
KEY WORDS: Cori cycle, fat body, honeybee workers, lactate, muscle, sores