Symbiotic Fungal Flora in Leaf Galls Induced by Illiciomyia yukawai (Diptera: Cecidomyiidae) and in Its Mycangia

Abstract

We investigated the association between a gall midge, Illiciomyia yukawai, and its symbiotic fungi on Japanese star anise, Illicium anisatum. The number of fungal species isolated from the galls increased with development of the galls, whereas those from the leaves showed a different trend. Botryosphaeria dothidea was dominant in the galls from June to October, and after that Phomopsis sp. 1, Colletotrichum sp., and Pestalotiopsis sp. became dominant. Although B. dothidea was not isolated from the leaves, it was detected from mycangia (abdominal sternite VII) of egg-laying adults at a high isolation frequency (>90%). However, B. dothidea was not isolated from mycangia of adults emerging from galls that were enclosed by plastic bags. This indicates that I. yukawai is closely associated with B. dothidea and that its newly emerged adults do not take the fungus into mycangia directly from the galls where they had developed. Also, the fungus from the fungal layers of ambrosia galls has less ability to propagate on artificial media despite the presence of its mycelial mass in mature galls.

Is a Gall an Extended Phenotype of the Inducing Insect? A Comparative Study of Selected Morphological and Physiological Traits of Leaf and Stem Galls onMachilus thunbergii(Lauraceae) Induced by Five Species ofDaphnephila(Diptera: Cecidomyiidae) in Northeastern Taiwan

“…However, because Botryosphaeria dothidea was consistently isolated from the galls on the Taiwanese populations of M. thunbergii induced by species of Daphnephila, we infer that B. dothidea is the primary associate and possibly a symbiont. Earlier studies (Bissett and Borkent, 1988;Adair et al, 2009;Rohfritsch, 2008;Kobune et al, 2012) indicating that the larvae of Asphondyliini depended on B. dothidea for their development reinforce our inference. The different fungal taxa isolated from mature galls induced by the same Daphnephila populations suggest that these Cecidomyiidae may use different species of secondary fungal associates possibly to enhance their nutrition.…”

Adult behavior of an ambrosia gall midge Illiciomyia yukawai (Diptera: Cecidomyiidae) and synchronization between its emergence and host plant phenology

“…Recently, Kobune et al . () confirmed the association between I. yukawai and its symbiotic fungus Botryosphaeria dothidea (Moug.) Cesati & De Notaris (Botryosphaeriales: Botryosphaeriaceae).…”

Biology of Asphondyliini (Diptera: Cecidomyiidae)

“…Because the fungus was not isolated from newly emerged adults, females were considered to take the fungus not directly from their galls but from other sites (Kobune et al . ).…”