%0 Journal Article
%T Patterns of functional enzyme activity in fungus farming ambrosia beetles
%A Henrik H De Fine Licht
%A Peter H W Biedermann
%J Frontiers in Zoology
%D 2012
%I BioMed Central
%R 10.1186/1742-9994-9-13
%X We discovered that the activity of cellulases in ambrosia fungus gardens is relatively small compared to the activities of other cellulolytic enzymes. Enzyme activity in all compartments of the garden was mainly directed towards hemicellulose carbohydrates such as xylan, glucomannan and callose. Hemicellulolytic enzyme activity within the brood chamber increased with gallery age, whereas irrespective of the age of the gallery, the highest overall enzyme activity were detected in the gallery dump material expelled by the beetles. Interestingly endo-¦Â-1,3(4)-glucanase activity capable of callose degradation was identified in whole-body extracts of both larvae and adult X. saxesenii, whereas endo-¦Â-1,4-xylanase activity was exclusively detected in larvae.Similar to closely related fungi associated with bark beetles in phloem, the microbial symbionts of ambrosia beetles hardly degrade cellulose. Instead, their enzyme activity is directed mainly towards comparatively more easily accessible hemicellulose components of the ray-parenchyma cells in the wood xylem. Furthermore, the detection of xylanolytic enzymes exclusively in larvae (which feed on fungus colonized wood) and not in adults (which feed only on fungi) indicates that only larvae (pre-) digest plant cell wall structures. This implies that in X. saxesenii and likely also in many other ambrosia beetles, adults and larvae do not compete for the same food within their nests - in contrast, larvae increase colony fitness by facilitating enzymatic wood degradation and fungus cultivation.Insects are the most abundant and diverse animal class on earth [1]. A key factor for their enormous success are adaptations to novel environments and food sources with the help of symbiotic microorganisms [2]. Insect hosts maintain prokaryotic, fungal, and bacterial associates in a variety of ways, which help them in nutrient acquisition and recycling, environmental detoxification, and defense against antagonists. By means of microbial
%K Symbiosis
%K Digestion
%K Enzyme
%K Insoluble chromogenic substrates
%K Xylomycetophagy
%K Xyleborinus saxesenii
%K Insect fungus farming
%K Social evolution
%K Division of labor
%U http://www.frontiersinzoology.com/content/9/1/13