Morphological identification and biological observations of Lopheucoila mexicana (Hymenoptera, Figitidae, Eucoilinae), a parasitoid of Neosilba batesi (Diptera, Lonchaeidae) in avocado

Abstract

The lance fly Neosilba batesi (Curran, 1932) (Diptera: Lonchaeidae) has traditionally been regarded as a secondary colonizer of damaged fruits, yet recent observations suggest it may infest developing avocado ( Persea americana Miller, 1768) fruits and contribute to premature fruit drop. Despite its potential economic importance, little is known about its natural enemies. In May 2025, fallen avocados were collected in Michoacán, Mexico, and puparia of N. batesi were reared under laboratory conditions to investigate associated parasitoids. A figitid parasitoid was recovered and morphologically identified. Morphological characters of females corresponded to Lopheucoila mexicana Weld, 1951 (Hymenoptera: Figitidae: Eucoilinae). Parasitism in field-collected puparia reached 4.7%. The duration of the egg-to-adult developmental period of this parasitoid could not be determined directly because the timing of oviposition by parasitoid females on the host larvae was unknown. A total of 1,933 N. batesi puparia were obtained from 125 avocado fruits collected in the field. Of these, 42 parasitoid adults emerged between 37 and 43 days after the infested avocado fruits were collected. The highest number of parasitoids emerged on day 44 (n = 20). After this day, the number of parasitoids emerging was 27 between 45 and 49 d. Other two parasitoids were recovered through dissection of the puparia. The sex ratio was female-biased (63.73%). The present study provides the first confirmed host record for L. mexicana and the first documentation of this parasitoid-host association in avocado. These findings expand current knowledge of Eucoilinae biology and highlight the potential role of native parasitoids in regulating N. batesi populations in avocado agroecosystems. They provide the basis for further work on its ecological role and applicability in biological control.