Maerua crassifolia Forssk. is an evergreen fodder tree whose fruits, flowers and especially the leaves constitute an important resource in the feeding of the herds on the rangelands in Niger. This study is part of the identification of insect dynamics in the foliage of Maerua crassifolia Forssk. (Capparidaceae) in the Niamey region (Niger).The study was carried out in two stands of Maerua crassifolia at Abdou Moumouni University in Niamey. Entomological observations were made on randomly selected forage trees representing at least 10% of each of the two stands. The entomological fauna associated with Maerua crassifolia as well as the main defoliating insects belonging to four orders (Lepidoptera, Coleoptera, Orthoptera, Isoptera) were determined. The entomofauna inventory revealed the presence of 24 species; these species belong to 11 orders of insects from 22 families. Caterpillars of the genus Belenois (Lepidoptera: Pieridae) were collected and identified as the main pests of Maerua crassifolia’s leaves.