Nectar intake rate is modulated by changes in sucking pump activity according to colony starvation in carpenter ants

FALIBENE, AGUSTINA; JOSENS, ROXANA

JOURNAL OF COMPARATIVE PHYSIOLOGY A-SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY

Springer

Año: 2008 vol. 194 p. 491 - 500

0340-7594

The dynamics of fluid feeding has been deeply studied in insects. However, the ability to vary the nectar intake-rate depending just on the carbohydrate deprivation of the colony has been clearly demonstrated only in the ant Camponotus mus. When insect morphometry and fluid properties remain constant, changes in intake rate could only be attributed to variations in the insect’s sucking pump activity. Previous records of the electrical activity generated during feeding in C. mus have revealed two different signal patterns: the Regular (RP, frequencies of 2-5Hz) and the Irregular (IP, frequencies of 7-12Hz) one. The present work studies the mechanism underlying the modulation of the food intake rate in ants by analysing whether these signal patterns are involved. Behaviour and electrical activity generated by ants at different starvation levels were analysed during feeding on sucrose solutions. Ants were able to modulate the intake rate for a variety of sucrose concentrations (10%, 40% and 60% w/w). The IP only occurred for 60% solutions and its presence did not affect the intake rate. However, during the RP generated under the starved state, we found frequencies up to 7.5 Hz. RP frequencies positively correlated with the intake rate for all sucrose concentrations. Hence, intake rate modulation according to the colony’s sugar deprivation is mainly achieved by the ant’s ability to vary the pumping frequency.