TY - JOUR

T1 - Can interaction specificity in the fungus-farming termite symbiosis be explained by nutritional requirements of the fungal crop?

AU - da Costa, Rafael R.

AU - Vreeburg, Sabine M. E.

AU - Shik, Jonathan Z.

AU - Aanen, Duur K.

AU - Poulsen, Michael

PY - 2019

Y1 - 2019

N2 - Fungus-growing termites are associated with genus-specific fungal symbionts, which they acquire via horizontal transmission. Selection of specific symbionts may be explained by the provisioning of specific, optimal cultivar growth substrates by termite farmers. We tested whether differences in in vitro performance of Termitomyces cultivars from nests of three termite species on various substrates are correlated with the interaction specificity of their hosts. We performed single-factor growth assays (varying carbon sources), and a two-factor geometric framework experiment (simultaneously varying carbohydrate and protein availability). Although we did not find qualitative differences between Termitomyces strains in carbon-source use, there were quantitative differences, which we analysed using principal component analysis. This showed that growth of Termitomyces on different carbon sources was correlated with termite host genus, rather than host species, while growth on different ratios and concentrations of protein and carbohydrate was correlated with termite host species. Our findings corroborate the interaction specificity between fungus-growing termites and Termitomyces cultivars and indicate that specificity between termite hosts and fungi is reflected both nutritionally and physiologically. However, it remains to be demonstrated whether those differences contribute to selection of specific fungal cultivars by termites at the onset of colony foundation.

AB - Fungus-growing termites are associated with genus-specific fungal symbionts, which they acquire via horizontal transmission. Selection of specific symbionts may be explained by the provisioning of specific, optimal cultivar growth substrates by termite farmers. We tested whether differences in in vitro performance of Termitomyces cultivars from nests of three termite species on various substrates are correlated with the interaction specificity of their hosts. We performed single-factor growth assays (varying carbon sources), and a two-factor geometric framework experiment (simultaneously varying carbohydrate and protein availability). Although we did not find qualitative differences between Termitomyces strains in carbon-source use, there were quantitative differences, which we analysed using principal component analysis. This showed that growth of Termitomyces on different carbon sources was correlated with termite host genus, rather than host species, while growth on different ratios and concentrations of protein and carbohydrate was correlated with termite host species. Our findings corroborate the interaction specificity between fungus-growing termites and Termitomyces cultivars and indicate that specificity between termite hosts and fungi is reflected both nutritionally and physiologically. However, it remains to be demonstrated whether those differences contribute to selection of specific fungal cultivars by termites at the onset of colony foundation.

KW - Biomass

KW - Carbohydrates

KW - Geometric framework

KW - Interaction specificity

KW - Macrotermes

KW - Nutrition

KW - Odontotermes

KW - Protein

KW - Symbiosis

KW - Termitomyces

U2 - 10.1016/j.funeco.2018.08.009

DO - 10.1016/j.funeco.2018.08.009

M3 - Journal article

AN - SCOPUS:85056213085

VL - 38

SP - 54

EP - 61

JO - Fungal Ecology

JF - Fungal Ecology

SN - 1754-5048

ER -