Fungal Volatiles as Olfactory Cues for Female Fungus Gnat, Lycoriella ingenua in the Avoidance of Mycelia Colonized Compost

Abstract

The chemical signatures emitted by fungal substrates are key components for mycophagous insects in the search for food source or for suitable oviposition sites. These volatiles are usually emitted by the fruiting bodies and mycelia. The volatiles attract fungivorous insects, like flowers attract pollinators; certain flowers mimic the shape of mushroom fruiting bodies and even produce a typical mushroom odor to exploit on fungus-insect mutualism. There are numerous insects which are mycophagous or eat fungi additionally, but only a few are considered a threat in agriculture. Lycoriella ingenua is one of the most serious pests in mushroom cultivation worldwide. Here we attempt to examine the role of environmental volatiles upon behavioral oviposition preference. In two-choice bioassays, fungus gnats preferred uncolonized compost compared to colonized compost but preferred colonized compost against nothing. However, when colonized compost was paired against distilled water, no significant choice was observed. The comparison of fresh casing material and mycelium colonized casing material resulted in no significant preference. From colonized compost headspace, three antennally active volatiles were isolated by gas chromatography coupled with electroantennography and subsequently identified with gas chromatography coupled mass spectrometry as 1-hepten-3-ol, 3-octanone and 1-octen-3-ol. In behavioral assays the addition of said synthetic volatiles to uncolonized compost separately and in combination to mimic colonized compost resulted in avoidance. We thus partially elucidate the role of fungal volatiles in the habitat seeking behavior of Lycoriella ingenua.

From plants to ants: Fungal modification of leaf lipids for nutrition and communication in the leaf-cutter ant fungal garden ecosystem

“…The study of fungal allelochemicals that influence insect behavior is not new, but we have taken a different approach in addressing this topic. Typically, behavior is observed between an insect and a fungus, and then work is done to identify the allelochemicals involved in that communication (35). Often, after identifying these allelochemicals, they are used as tools in pest management (36).…”

Specialized pollination by cecidomyiid flies and associated floral traits in Vincetoxicum sangyojarniae (Apocynaceae, Asclepiadoideae)

“…The compound 1‐octen‐3‐ol, also known as mushroom alcohol, is characteristic of fungal volatiles and associated with the earthy, yeasty odours of mushrooms (Johnson & Jürgens 2010; Kecskeméti et al . 2020). This compound has also been found in earthy (often foul) floral scents in plants of various families, most often in species of Orchidaceae, Araceae and Aristolochiaceae (Knudsen et al .…”

“…The compound 1-octen-3-ol, also known as mushroom alcohol, is characteristic of fungal volatiles and associated with the earthy, yeasty odours of mushrooms (Johnson & J€ urgens 2010;Kecskem eti et al 2020). This compound has also been found in earthy (often foul) floral scents in plants of various families, most often in species of Orchidaceae, Araceae and Aristolochiaceae (Knudsen et al 2006) whose main pollinators are mycophagous flies (i.e., Diptera that feed on fungi), e.g., the orchid Dracula lafleurii (Policha et al 2016) and Anthurium salvadorense (Araceae) (Schwerdtfeger et al 2002), both pollinated by flies of the family Drosophilidae, and the orchid Malaxis monophyllos, visited by drosophilids, mosquitoes, and fungus gnats of the families Mycetophilidae and Sciaridae (Jermakowicz et al 2022).…”

From Plants to Ants: Fungal Modification of Leaf Lipids for Nutrition and Communication in the Leaf-Cutter Ant Fungal Garden Ecosystem

“…The study of fungal allelochemicals that influence insect behavior is not new, but we have taken a different approach in addressing this topic. Typically, behavior is observed between an insect and a fungus, and then work is performed to identify the allelochemicals involved in that communication ( 35 ). Often, after identifying these allelochemicals, they are used as tools in pest management ( 36 ).…”