CommentaryOn interactions, associations, mycetangia, mutualists and symbiotes in insect-fungus symbioses
Introduction
In “Advice to a Young Scientist,” P.B. Medawar (1981) writes: “Another little rule (for medical scientists especially) is that mice, rats, and other laboratory animals should never be injected. Few hypodermic needles are large enough for even the smallest mouse to pass through, especially if it is injected with something. (“Mice were injected with rabbit serum albumin mixed with Freund's adjuvant,” we read. “Ah, but what into?” the cry goes up.) Mice should receive injections, or substances should be injected into them.” This is a humorous example of imprecise scientific writing, and many papers have been published on the importance and need for defining and using precise terminology, e.g., ecological terms (Jax et al., 1992), parasitism and symbiosis (Lewin, 1982), symbiosis (Martin and Schwab, 2013), psychology and psychiatry (Lillenfeld et al., 2015), kairomones (Ruther et al., 2002), microbiome studies (Tipton et al., 2019), sustainability (Glavič and Lukman, 2007), and endophytism (Wilson, 1995), among others.
To better understand insect-fungus symbioses, it is important to define the use of various terms commonly used in the scientific literature, associations vs. interactions, mycetangia vs. mycangia, symbiote vs. symbiont, and symbiosis vs. mutualism. Our goal is to encourage scientists to use a common and correct terminology.
Section snippets
Associations vs. interactions
In a biotic association (co-occurrence), the specific effects of two dissimilar organisms on each other might or might not be known and could also be referred to as a symbiosis. In contrast, use of the term interaction, implies, by definition, a reciprocal action or influence (The New Shorter Oxford English Dictionary, 1993), i.e., a particular effect of “organism A” on “organism B” has been determined, and vice versa. It is quite common to see the term “interaction” in the scientific
Refer to them as symbiotes, not symbionts
The term “symbiosis” originates from the Greek συμβιώσεως (sumbíōsis), meaning “living together.” In 1879, the German scientist Heinrich Anton de Bary (1831–1888), gave the word a biological context, defining it as “dissimilarly named organisms that live together, in symbiosis, as we can call these associations” (de Bary, 1879; Oulhen et al., 2016). This definition was influenced by the German botanist Albert Bernhard Frank's (1839–1900) previous use of the word “symbiotismus” (Sapp, 1994;
If the beneficial effect is known, they are mutualists, not symbiotes
The term “mutualism” was coined in the early 1870s by the Belgian zoologist Pierre-Joseph van Beneden (1809–1894), when he classified species interactions as mutualistic, parasitic or commensalistic (van Beneden, 1873, 1876). He defined mutualisms as species that live in close proximity and render each other mutual services (van Beneden, 1876; Sapp, 2010). The close proximity also defines symbiosis (see above) and this shared character with mutualism was probably the reason for “the greatest
Do bark beetles have mycetangia or is it mycangia?
Two terms have been used in the scientific literature to refer to cuticular invaginations that carry fungal spores in bark beetles: mycetangia and mycangia. Before these terms were coined, the structures in ambrosia beetles were referred to as “holes” and “openings” (Nunberg, 1951), “skin-gland organs” (translated from the German “Hautdrüsenorgane”; Francke-Grosmann, 1956), “fungal storage sac” (Fernando, 1959), and “specialized areas”, “well defined sacs” and “fungus-carrying structure” (
Conclusions
According to Browne (1853), “it is wisdom to profit by the errors of others.” We provide evidence as to why there is an important difference between an association and an interaction, mycetangia vs. mycangia, symbiote vs. symbiont, and symbiosis vs. mutualism. There is no justification for using incorrect or imprecise scientific terminology. It is time to profit from the errors of others.
Acknowledgements
Comments by Meredith Blackwell, Lynne Boddy, Henrik H. De Fine Licht, Sarah Emche, Chase G. Mayers, George O. Poinar, Jr., and Ann Simpkins on a previous version of this manuscript are greatly appreciated. Special thanks to Wayne Olson (USDA, National Agricultural Library) for literature searches. Peter Biedermann was funded by the German Research Foundation (DFG Emmy Noether Grant BI 1956/1–1).
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