Ground-breaking research into worms could be vital for the environment and life itself
Earthworms have been studied closely for more than a century. Charles Darwin produced a book on the creatures that has observations that are still relevant today. However, there is still a great deal that is not known about them - and a great deal that we can gain from them.
With funding from the Organisation for Economic Cooperation and Development, I worked with soil physicists from the United States Department of Agriculture's Agricultural Research Service at the North Appalachian Experimental Watershed in the United States, spending several months characterising the burrows of lob worms using acrylic resin casts. Coupled with water infiltration experiments, this allowed us to calculate the amount of water taken into the soil through "macropores" produced by these worms. The results suggested that the presence of this alien species in Ohio agricultural systems prevented tremendous over-surface water flow and associated erosion.
Through work funded by Manchester Airport, my research group has recorded earthworm species, numbers and masses at grassland sites translocated by the construction of the second runway. These data are of vital importance as a number of protected species that feed on earthworms, such as great-crested newts and badgers, were also translocated during this development.
As agents in the improvement, and even formation, of soil, earthworms play an important role simply by going about their everyday activities.
Over the past two years, British Council funding has enabled me to visit Poland, where I have studied, in conjunction with workers from Rzeszow, the earthworms of the Bieszczady National Park. The basic ecology of certain animals, such as Allolobophora carpathica , an endemic species of the beech forests of the Carpathian Mountains, has remained relatively unknown. This species is now being reared in laboratories, where its potential for soil restoration is being studied.
Forthcoming "ground-breaking" research in Finland, funded by the Leverhulme Trust, will focus on dispersal and distribution patterns of lob worms. Although this species was recognised and named by Linnaeus in the 18th century, some fundamental aspects of its ecology are still not fully understood. When do hatchling earthworms "strike out" from the parental midden? Do they occupy vacated adult burrows? Or is there a need to dig and extend a burrow as they grow? Equally, these sexually reproducing, albeit hermaphroditic, organisms need to seek gene exchange from distantly related kin. Therefore, overland travel, far from being a result of the flooding of a burrow, may be an evolutionary trait to prevent inbreeding.
This work builds on previous research in which we examined this animal's mating behaviour using infrared cameras to videotape sequences lasting several hours. Far from being a simple, mechanistic process, the lob worms, on encountering each other, "check out" their potential partner through reciprocated burrow visits before mating.
Two other major areas of earthworm research that our group is preparing to investigate are the use of certain species for degradation of waste organic matter and their use as tools for assessing ecotoxicological substances. The former is of growing importance now that increased recycling initiatives are proposed. The latter is also vital, as we continue to produce chemicals that may have detrimental effects on the environment and the life, including ourselves, within it.
Kevin Butt is principal lecturer in environmental management at the University of Central Lancashire.