Abstract
Links between (human) economics and evolutionary biology are old. A seminal meeting between the disciplines is of course Charles Darwin's reading of Thomas Malthus (1838), but dialogue has been ongoing throughout the 20th century and until today. Yet, economics is far from being a unified field, as illustrated by the contemporary divide between orthodox and heterodox economics. Taking this into account opens for a new perspective on the questions of how strong the unifying potential of economic thinking is for evolutionary biology, and of how desirable unification is for the discipline. Using the example of the singing behaviour of the marsh warbler (Acrocephalus palustris), I will show how different theories about an "economy of nature" (focusing on the economics of song) can be found in the scientific literature, and I will account for relations between them (complementarity, incompatibility, etc.). On the basis of a historical, conceptual and empirical approach, I will then sketch some ways to further deal with the question of theory choice, in a case where several options are conceivable a priori.