TY - JOUR
T1 - Metabolic cost of flight and aerobic efficiency in the rose chafer, Protaetia cuprea (Cetoniinae)
AU - Urca, Tomer
AU - Levin, Eran
AU - Ribak, Gal
N1 - Publisher Copyright:
© 2022 The Authors. Insect Science published by John Wiley & Sons Australia, Ltd on behalf of Institute of Zoology, Chinese Academy of Sciences.
PY - 2022/10
Y1 - 2022/10
N2 - Rose chafer beetles (Protetia cuprea) are pollinators as well as agricultural pests, flying between flowers and trees while foraging for pollen and fruits. Calculating the energy they expend on flying during foraging activity faces the challenge of measuring the metabolic rate (MR) of free-flying insects in an open space. We overcame this challenge by using the bolus injection of 13C Na-bicarbonate technique to measure their metabolic energy expenditure while flying in a large flight arena. Concurrently, we tracked the insects with high-speed cameras to extract their flight trajectory, from which we calculated the mechanical power invested in flying for each flight bout. We found that the chemical (metabolic) energy input converted to mechanical flight energy output at a mean efficiency of 10.4% ± 5.2%, with a trend of increased efficiency in larger conspecifics (efficiency scaled with body mass to the power of 1.4). The transition in the summer from a diet of pollen to that of fruits may affect the energy budget available for foraging. Starved P. cuprea, feeding on apples ad libitum, increased their body mass by an average of 6% in 2 h. According to our calculations, such a meal can power a 630-m flight (assuming a carbohydrate assimilation efficiency of 90%). Pollen, with a low water and carbohydrate content but rich in proteins and lipids, has a higher caloric content and should assimilate differently when converting food to flight fuel. The high cost of aerial locomotion is inherent to the foraging behavior of rose chafers, explaining their short flight bouts followed by prolonged feeding activity.
AB - Rose chafer beetles (Protetia cuprea) are pollinators as well as agricultural pests, flying between flowers and trees while foraging for pollen and fruits. Calculating the energy they expend on flying during foraging activity faces the challenge of measuring the metabolic rate (MR) of free-flying insects in an open space. We overcame this challenge by using the bolus injection of 13C Na-bicarbonate technique to measure their metabolic energy expenditure while flying in a large flight arena. Concurrently, we tracked the insects with high-speed cameras to extract their flight trajectory, from which we calculated the mechanical power invested in flying for each flight bout. We found that the chemical (metabolic) energy input converted to mechanical flight energy output at a mean efficiency of 10.4% ± 5.2%, with a trend of increased efficiency in larger conspecifics (efficiency scaled with body mass to the power of 1.4). The transition in the summer from a diet of pollen to that of fruits may affect the energy budget available for foraging. Starved P. cuprea, feeding on apples ad libitum, increased their body mass by an average of 6% in 2 h. According to our calculations, such a meal can power a 630-m flight (assuming a carbohydrate assimilation efficiency of 90%). Pollen, with a low water and carbohydrate content but rich in proteins and lipids, has a higher caloric content and should assimilate differently when converting food to flight fuel. The high cost of aerial locomotion is inherent to the foraging behavior of rose chafers, explaining their short flight bouts followed by prolonged feeding activity.
KW - aerobic efficiency
KW - bolus injection of C-Na-bicarbonate
KW - feeding capacity
KW - flight metabolic rate
KW - flower chafer beetle
KW - free flight
KW - mechanical power
UR - http://www.scopus.com/inward/record.url?scp=85127227093&partnerID=8YFLogxK
U2 - 10.1111/1744-7917.13011
DO - 10.1111/1744-7917.13011
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C2 - 35142427
AN - SCOPUS:85127227093
SN - 1672-9609
VL - 29
SP - 1361
EP - 1372
JO - Insect Science
JF - Insect Science
IS - 5
ER -