Insect-food-plant associations have been shown to be influenced by the chemical, physical and nutritional characteristics of plants. We suggest that among insect larvae that use leaf material to build shelters, food-plant use may be constrained by differences in host leaf structure, illuminating a rarely investigated aspect of insect-plant interactions. To explore the potential effects of leaf structure on shelter building behavior in a Neotropical skipper butterfly, we investigated shelter building patterns on two congeneric food-plants that varied in leaf thickness. Shelter architecture varied significantly between hosts, with thicker leaves requiring longer cuts to construct shelters. The relationship between shelter building behavior and leaf structure is discussed in relation to selection pressures on larval shelters and food-plant choice.

Estimating the survivorship of lepidopteran larvae in the field poses many problems, most notably the potential for monitored subjects to simply wander away. Larvae of the family Hesperiidae, however, construct and dwell in shelters built out of leaf tissue on their host plants, return to their shelters between feeding bouts, and build a predictable series of shelters during larval ontogeny. Here we describe the shelter building behavior of Pyrrhopyge papius Hopffer, 1874 from northeastern Ecuador. Subsequently we test the use of the Mayfield method, a widely-used ornithological method for estimating survivorship of nests, to examine its utility for monitoring survival in free-living hesperiid larvae. Pyrrhopyge papius builds three distinct shelter types during its ontogeny. Monitoring of larvae in the field was successful, generating a predicted 16.4% survivorship from hatching to pupation. We found no significant differences in survivorship between larval shelter types, and only marginally significant differences between years. The Mayfield method of data collection and analysis may be a useful tool for some studies of survivorship in free-living lepidopteran larvae.