Does Hartigiola annulipes (Diptera: Cecidomyiidae) distribute its galls randomly?

• Main Authors: Sebastian PILICHOWSKI, Marian J. GIERTYCH
• Format: Article
• Language: English
• Published: Institute of Entomology, Biology Centre, Czech Academy of Science 2018-09-01
• Series: European Journal of Entomology
• Subjects: diptera; cecidomyiidae; hartigiola annulipes; gall midge; gall distribution; leaf zones; specific leaf area; cardinal directions
• Online Access: https://www.eje.cz/artkey/eje-201801-0050_Does_Hartigiola_annulipes_Diptera_Cecidomyiidae_distribute_its_galls_randomly.php

It is expected that environmental conditions impact the distribution of galls on host plants. Moreover, insects may induce their galls randomly or choose certain parts of a host to induce such growths. This study aimed to determine whether or not the gall midge, Hartigiola annulipes (Diptera: Cecidomyiidae), which induces galls on leaves of the European beech (Fagus sylvatica), prefers leaves facing a particular cardinal direction. In addition, we wanted to ascertain whether the galls are evenly spread across three leaf zones: proximal, median and distal, distinguished by dividing leaf area along the midrib. The results show that H. annulipes chose leaves facing various directions in different studied locations, and leaf choice is not restricted to the specific leaf area, a parameter that accurately reflects the light conditions of leaf growth. Moreover, the medial leaf zone was preferred, while the distal zone was avoided. The choice of the leaf zone modified the distance between the mid-rib and a gall. Gall distribution in the crown of trees is probably random, while at the leaf level, it is determined by leaf morphology.