Why some fungi senesce and others do not: An evolutionary perspective on fungal senescence

Fungi are generally considered to be modular organisms with no clear distinction of a germ line: With the expansion of the mycelium, chances for reproduction are expected to increase, and each unit under favourable circumstances may produce offspring. Fungi with such modular body plans are expected to be long-lived, as most fungi indeed seem to be. However, fungi exist that do senesce, and their growth often seems to be limited by space or time. For these fungi, we can consider the term 'pseudo-unitary', as life history details and ecological conditions constrain the size of the soma and the opportunities for reproduction. We may predict the life history traits and ecological conditions that favour such evolution of fungal senescence. Known proximate mechanisms of fungal senescence can be viewed in the light of this evolutionary context.