TY - JOUR
T1 - Carbohydrate and lipid metabolism during the last larval moult of the tobacco hornworm, Manduca sexta
AU - Siegert, Karl J.
AU - Speakman, John R.
AU - Reynolds, Stuart E.
PY - 1993/12/31
Y1 - 1993/12/31
N2 - Abstract. At 25°C and with a light regime of 17 h light and 7h dark, the last larval moult of the tobacco hornworm, Manduca sexta, lasts approximately 32 h, during which profound changes of metabolism were observed. At the onset of the moult, which coincides with the cessation of feeding, the proportion of active fat body glycogen phosphorylase increased from 10 (‐2h) to 25–30% (Oh). A biphasic pattern with peak activities of 45–50% after t – 12 h and again just prior to the shedding of the cuticle (32 h) was subsequently observed. Haemolymph trehalose concentration decreased significantly from c. 35 (Oh) to 20mM (8h), but then recovered to an intermediate level (30mM; 12h). After completion of the moult, the trehalose concentration was 35–40 mM. The haemolymph glucose level in feeding fourth instar larvae was 4–5 mM, but decreased sharply before the onset of the moult to c. 1 mM, followed by a slow 6‐fold increase over the next 20h. Prior to the shedding of the cuticle, the glucose level dropped again dramatically. The haemolymph lipid level increased slowly from an initial level of 1.2–1.4mg/ml during the early part of the moult, reaching a maximum of 1.8mg/ml after /= 16 h. Afterwards, a decrease of c. 50% was observed until ecdysis occurred. Oxygen consumption per animal decreased steadily from 30–35 μl/min pre‐moult by approximately 70% to c. 10 μl/min but started to increase about 5 h before the animals resumed feeding.
AB - Abstract. At 25°C and with a light regime of 17 h light and 7h dark, the last larval moult of the tobacco hornworm, Manduca sexta, lasts approximately 32 h, during which profound changes of metabolism were observed. At the onset of the moult, which coincides with the cessation of feeding, the proportion of active fat body glycogen phosphorylase increased from 10 (‐2h) to 25–30% (Oh). A biphasic pattern with peak activities of 45–50% after t – 12 h and again just prior to the shedding of the cuticle (32 h) was subsequently observed. Haemolymph trehalose concentration decreased significantly from c. 35 (Oh) to 20mM (8h), but then recovered to an intermediate level (30mM; 12h). After completion of the moult, the trehalose concentration was 35–40 mM. The haemolymph glucose level in feeding fourth instar larvae was 4–5 mM, but decreased sharply before the onset of the moult to c. 1 mM, followed by a slow 6‐fold increase over the next 20h. Prior to the shedding of the cuticle, the glucose level dropped again dramatically. The haemolymph lipid level increased slowly from an initial level of 1.2–1.4mg/ml during the early part of the moult, reaching a maximum of 1.8mg/ml after /= 16 h. Afterwards, a decrease of c. 50% was observed until ecdysis occurred. Oxygen consumption per animal decreased steadily from 30–35 μl/min pre‐moult by approximately 70% to c. 10 μl/min but started to increase about 5 h before the animals resumed feeding.
KW - Fat body glycogen phosphorylase
KW - haemolymph metabolites
KW - oxygen consumption.
UR - http://www.scopus.com/inward/record.url?scp=0027140708&partnerID=8YFLogxK
U2 - 10.1111/j.1365-3032.1993.tb00614.x
DO - 10.1111/j.1365-3032.1993.tb00614.x
M3 - Article
AN - SCOPUS:0027140708
SN - 0307-6962
VL - 18
SP - 404
EP - 408
JO - Physiological entomology
JF - Physiological entomology
IS - 4
ER -