Sexual differences in weight loss upon eclosion are related to life history strategy in Lepidoptera

► Considerable weight loss upon eclosion (50-80%) is ubiquitous among Lepidoptera. ► In more capital breeding and in more pro-ovigenic Lepidoptera, females retain water. ► Results suggest that metamorphosis is generally facilitated by high water content, while adults excrete water upon eclosion to benefit flight unless water has been allocated to eggs, or is treated as a capital resource for adult survival or future allocation to eggs.