Partner associations across sympatric broad‐headed bug species and their environmentally acquired bacterial symbionts. Issue 6 (7th February 2014)

• Record Type: Journal Article
• Authors: Garcia, J. R.; Laughton, A. M.; Malik, Z.; Parker, B. J.; Trincot, C.; S. L. Chiang, S.; Chung, E.; Gerardo, N. M.
• Is Part Of: Molecular ecology. Volume 23:Issue 6(2014)
• Page Start: 1333
• Page End: 1347
• Publication Date: 2014-02-07
• Subjects: Molecular ecology -- Periodicals; Molecular population biology -- Periodicals; 576
• DOI: 10.1111/mec.12655
• Languages: English
• ISSNs: 0962-1083

Abstract

<abstract abstract-type="main" id="mec12655-abs-0001"> <title>Abstract</title> <p>Many organisms have intimate associations with beneficial microbes acquired from the environment. These host–symbiont associations can be specific and stable, but they are prone to lower partner specificity and more partner‐switching than vertically transmitted mutualisms. To investigate partner specificity in an environmentally acquired insect symbiosis, we used 16S rRNA gene and multilocus sequencing to survey the bacterial population in the bacteria‐harbouring organ (crypts) of 49 individuals across four sympatric broad‐headed bug species (<italic>Alydus calcaratus</italic>, <italic> A. conspersus</italic>, <italic> A. tomentosus</italic> and <italic>Megalotomus quinquespinosus</italic>). Similar to other insect–bacteria associations, <italic>Burkholderia</italic> spp. were the most common residents of the crypts in all four insect species (77.2% of recovered sequences). <italic>Burkholderia</italic> presence was associated with prolonged survival to adulthood in <italic>A. tomentosus</italic>, suggesting a beneficial role of these specialized associations. <italic>Burkholderia</italic> were also found in environmental reservoirs in the insects' habitat, which may facilitate acquisition by insects by increasing <italic>Burkholderia</italic>–insect encounters. Symbiont establishment could also be facilitated by resistance to insect defences; zone of inhibition assays demonstrated that <italic>Burkholderia</italic> and other bacteria isolated from crypts are resistant to insect defences that limit growth of <italic>Escherichia coli</italic>. Alternatively, the insects' defences may not efficiently kill a broad range of bacteria. Although the symbiosis is targeted to <italic>Burkholderia</italic>, the insects' crypts housed other bacteria, including non‐<italic>Burkholderiaceae</italic> species. There is no significant effect of host insect species on <italic>Burkholderia</italic> distribution, suggesting a lack of strong partner specificity at finer scales. The presence of frequent partner‐switching between sympatric insects and their symbionts likely prevents tight co‐evolutionary dynamics.</p> </abstract>