24. NON-PREFERENCE OF THE CATALPA SPHINX, CERATOMIA CATALPAE (LEPIDOPTERA: SPHINGIDAE) TO INVERTEBRATE PREDATORS

ABSTRACT Aposematic traits such as bright contrasting coloration and gregarious feeding are often signals to predators that a potential prey is unpalatable. Larvae of Ceratomia catalpae, the catalpa sphinx, show aposematic traits and sequester catalpol, a secondary compound from their host plant Catalpa spp. Catalpol sequestration by other caterpillar species has been shown to deter both invertebrate and vertebrate predators, but the palatability of C. catalpae has not been explicitly tested. Choice tests with both spiders (Hogna carolinensis) and predatory hemipterans (Podisus maculiventris) showed that predators naïve to both C. catalpae and the alternate prey Trichoplusia ni and Manduca sexta preferred the alternate species, and that P. maculiventris that were exposed previously to T. ni also preferred T. ni. In non-choice tests, P. maculiventris grew significantly slower upon C. catalpae compared to M. sexta. These results suggest that C. catalpae, like other caterpillars that sequester catalpol, is unpalatable and that the catalpol is an effective chemical defense against invertebrate predators