The effect of ambient humidity on the foraging behavior of the hawkmoth Manduca sexta

Heidy L. Contreras, Joaquin Goyret, Martin von Arx, Clayton T. Pierce, Judith L. Bronstein, Robert A. Raguso, Goggy Davidowitz

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


The foraging decisions of flower-visiting animals are contingent upon the need of an individual to meet both energetic and osmotic demands. Insects can alter their food preferences to prioritize one need over the other, depending on environmental conditions. In this study, preferences in nectar sugar concentrations (0, 12, 24 %) were tested in the hawkmoth Manduca sexta, in response to different levels of ambient humidity (20, 40, 60, and 80 % RH). Moths altered their foraging behavior when placed in low humidity environments by increasing the volume of nectar imbibed and by consuming more dilute nectar. When placed in high humidity environments the total volume imbibed decreased, because moths consumed less from dilute nectars (water and 12 % sucrose). Survivorship was higher with higher humidity. Daily foraging patterns changed with relative humidity (RH): moths maximized their nectar consumption earlier, at lower humidities. Although ambient humidity had an impact on foraging activity, activity levels and nectar preferences, total energy intake was not affected. These results show that foraging decisions made by M. sexta kept under different ambient RH levels allow individuals to meet their osmotic demands while maintaining a constant energy input.

Original languageEnglish (US)
Pages (from-to)1053-1063
Number of pages11
JournalJournal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology
Issue number11
StatePublished - Nov 2013


  • Feeding behavior
  • Hawkmoths
  • Manduca sexta
  • Nectar preference
  • Osmoregulation

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • Animal Science and Zoology
  • Behavioral Neuroscience


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