Biology subjects

Diehl, J. M. C.

Publications and source records attributed to Diehl, J. M. C..

2 recordsLinked to original sources

bioRxiv2022

Friend or Foe: Ambrosia Beetle response to volatiles of common threats in their fungus gardens

Fungus farming insects encounter multiple microbial threats in their cultivar gardens. They can affect both the nutritional cultivar and the insects health. In this study, we explored the potential of ambrosia beetles and their larvae to detect the presence of ubiquitous weed or entomopathogenic fungi. The ability to recognize a threat offers individuals a chance to react. Our study organism, the fruit-tree pinhole borer, Xyleborinus saxesenii, is associated with two mutualistic fungi, Dryadomyces sulphureus (Raffaelea sulphurea) and Raffaelea canadensis. Both symbionts were tested in combinations with two common fungus-garden weeds (Aspergillus sp. and Penicillium commune) and the entomopathogen Beauveria bassiana in two-choice experiments. Behavioural repellence was found in many, but not all combinations. Larvae and adult females showed an opposite reaction towards the entomopathogen, whereas for Aspergillus sp., neither provoked repellence nor attraction of larvae and adult females, if R. canadensis was used as lure. Our results validate a response of both larvae and adult ambrosia beetles towards other fungal volatiles. Their decision to confront a potential threat or preferably to avoid it could be subject to a more complex context.

animal behavior and cognition↗

bioRxiv2022

First experimental evidence for active farming in ambrosia beetles and strong heredity of garden microbiomes

Fungal cultivation is a defining feature for advanced agriculture in attine ants and fungus-farming termites. In a third supposedly fungus-farming group, wood-colonizing ambrosia beetles (Curculionidae: Scolytinae and Platypodinae), an experimental proof for the effectiveness of beetle activity for selective promotion of their food fungi over others is lacking and farming has only been assumed based on observations of social and hygienic behaviors. Here, we experimentally removed mothers and their offspring from young nests of the fruit-tree pinhole borer, Xyleborinus saxesenii (Scolytinae). By amplicon sequencing of bacterial and fungal communities of nests with and without beetles we could show that beetles are indeed able to actively shift symbiont communities. Although being consumed, the Raffaelea food fungi were more abundant when beetles were present while a weed fungus (Chaetomium sp.) as well as overall bacterial diversity were reduced in comparison to nests without beetles. Core symbiont communities were generally low diverse and there were strong signs for vertical transmission not only for the cultivars, but also for secondary symbionts. Our findings verify the existence of active farming, even though the exact mechanisms underlying the selective promotion and/or suppression of symbionts need further investigation.

ecology↗