The larvae of Eucheira socialis construct and maintain a silk shelter over their 10-month larval stage. Previous work in the laboratory demonstrated differences between final (sixth) instar male and female larval behavior with males allocating more time to nest maintenance (silk spinning) and less time to feeding than females. We report here the results of field studies conducted on fifth and sixth instar larvae. Fifth instar males and females did not differ in their behavior while sixth instar male caterpillars emerged from the nest earlier, allocated more time to nest maintenance and less time to foraging than females.