We evaluated the larval host plant specificity of Cerambycidae in a tropical lowland rainforest in Panama.Beetleswere reared from standardized timber baits of freshly-cut wood exposed for 35 days to ovipositing females in the Galeta Island Protected Area, Colón province, Panama. Baits from six species of woody plants belonging to five families yielded 109 longhorn beetles, representing 11 species in nine genera.Host specificity was low,with themajority of longhorn species reared fromwood of more than one plant family. Only the genus Inga Mill. (Fabaceae) hosted a possibly specialized species (Cosmotoma fasciata Fisher). Longhorn abundance and diversity were highest in Gustavia superba (Kunth) O. Berg (Lecythidaceae). Most adults emerged four and six months after the timber baits were exposed. Fifty-seven percent of longhorn beetles were reared from low wood density trees (400–460 kg/m³); we do not have enough data to propose reliable wood density preferences for other cerambycids reared in this study. More rearing samples will be required to support the results shown in this paper.