Biology of the sexual generation of Loxaulus hyalinus (Hymenoptera: Cynipidae) in Quercus laeta Liebm. oakgroves in Mexico City

Introduction: Loxaulus hyalinus is a cynipid (Hymenoptera) that attacks oak groves (Quercus laeta Liebm.) in Mexico City. The insect’s biology and damage potential are unknown. Objectives: Describe the biology of the sexual phase of L. hyalinus and its effects on Q. laeta, and list the associated inquilines and parasitoids. Materials and methods: To determine the period of each stage of L. hyalinus, galls were collected from infested twigs and periodically dissected to describe their development and the presence of inquilines and parasitoids in the period 2019- 2022. Results and discussion: Sexual generation began in October when the first symptoms of galls development were observed on twigs, and concluded in May of the following year, when adults emerged. The presence of many galls alters the growth pattern of the tree crown. Two Synergus species were found as inquilines and nine genera of chalcidoid parasitoids were associated with L. hyalinus. Conclusions: Sexual generation of L. hyalinus develops in twig galls and its only host confirmed is Q. laeta. This pest causes no death of its host but severely affects the shape of the crown.