Charles Darwin, earthworms and the natural sciences: various lessons from past to future

Abstract

In 1881, Darwin (1809–1882) published his last scientific book entitled “The formation of vegetable mould through the action of worms with observations on their habits”, the result of several decades of detailed observations and measurements on earthworms and the natural sciences. The work was considered a “best-seller” at the time, with 3500 copies sold immediately and 8500 in less than 3 years which, at the time, rivaled the sale of his most well known book “On the origin of species”. The book covers the importance of earthworm activity on a variety of topics: pedogenesis and weathering processes, soil horizon differentiation and the formation of vegetable mould (topsoil), the role of earthworm burrowing and casting (bioturbation) in soil fertility and plant growth, the burial of organic materials and soil enrichment with mineral elements, the global cycle of erosion–sedimentation with hydrologic and aerial transfers of fine particles brought up to the soil surface by earthworms and the protection of archaeological remains through their burial. Finally, Darwin also performed a series of original experiments to determine if earthworms possessed, or not, a certain “intelligence”. This part of the book was, among others, one of the main reasons for its success. In this article we analyze the success (past and present) of this book, Darwin’s own opinion of his book and the general contents of the work. Throughout, we discuss the main lessons to be learned from his ‘little’ (as he called it) book and provide brief historic reviews of major literary works on earthworms, both contemporary and posterior to Darwin, emphasizing his role as precursor and/or founder of various scientific disciplines (ethology, soil ecology and pedology). However, despite Darwin’s clear demonstrations of the importance of biological activities (earthworms) in the maintenance of soil fertility, his book on worms has been mostly neglected by agronomists and soil scientists, primarily due to the predominant soil fertility and management paradigms of the 19th and 20th centuries.