This study aims to analyze difficulties that pre-service elementary teachers experience in investigating the life cycle of a common cabbage butterfly in person. As difficulties they face during the process of this research, they pointed out collecting eggs, observing molting, creating environments for a breeding cage, feeding, building a breeding cage, and making butterfly specimens. Out of all the environmental difficulties related to their school fields, they pointed out a difficulty of time management most of all, followed by placing a breeding cage in the classroom and the lack of microscopes for observation. In regard to difficulties related to their evaluations on students` activities, they found it difficult to evaluate students` activity with the life cycle of an insect in the aspect of knowledge and even to set evaluation criteria. Besides, many of them responded that it would be appropriate to evaluate a research on the life cycle of an insect through a portfolio or an observation journal. In regard to difficulties in terms of teachers` knowledge, they found it difficult to understand insect molting, metamorphoses, complete metamorphoses, incomplete metamorphoses, the structure of an insect body, and how to distinguish a female insect from a male one. In regard to the application of class models, they knew it is important for students to have various experiences through direct observation, so the experience-based learning model was proper for the process of observing the life cycle of a common cabbage butterfly. However, they found it difficult for students to observe each stage of the life cycle in person.