Minding the miniscule: the scale prejudice in everyday life

I was recently weeding a vegetable bed in the garden when out of the corner of my eye I noticed a centipede frantically heading for cover after I had inadvertently disturbed its hiding spot. In my experience, most gardeners are oblivious to the diminutive fauna and flora around them unless they are pests targeted for removal or obliteration. It's only when the likes of a biting or stinging organism - or even just a large and/or hairy yet harmless spider - comes into view do people consciously think about the miniature cornucopia of life around them.

Even then, we consider our needs rather greater than theirs: how many of us stop to consider the effect we are having when we dig up paving slabs and find a bustling ant colony underneath? In his 2004 essay Dolittle and Darwin, Richard Dawkins pondered what contemporary foible or -ism future generations will castigate us for. Something I consider worth looking at in this context is scale-ism, which might be defined as the failure to apply a suitable level of consideration to life outside of 'everyday' measurements.

I've previously discussed neo-microscopic water-based life but larger fauna visible without optical aids is easy to overlook when humans are living in a primarily artificial environment - as over half our species is now doing. Several ideas spring to mind as to why breaking this scale-based prejudice could be important:

1. Unthinking destruction or pollution of the natural environment doesn't just cause problems for 'poster' species, predominantly cuddly mammals. The invertebrates that live on or around larger life-forms may be critical to these ecosystems or even further afield. Removal of one, seemingly inconsequential, species could allow another to proliferate at potentially great cost to humans (for example, as disease vectors or agricultural pests). Food webs don't begin at the chicken and egg level we are used to from pre-school picture books onwards.
2. The recognition that size doesn't necessarily equate to importance is critical to the preservation of the environment not just for nature's sake but for the future of humanity. Think of the power of the small water mould Phytophthora agathidicida which is responsible for killing the largest residents of New Zealand's podocarp forests, the ancient coniferous kauri Agathis australis. The conservation organisation Forest and Bird claims that kauri are the lynchpin for seventeen other plant species in these forests: losing them will have a severe domino effect.
3. Early detection of small-scale pests may help to prevent their spread but this requires vigilance from the wider public, not just specialists; failure to recognise that tiny organisms may be far more than a slight nuisance can be immensely costly. In recent years there have been two cases in New Zealand where the accidental import of unwanted insects had severe if temporary repercussions for the economy. In late 2017 three car carriers were denied entry to Auckland when they were found to contain the brown marmorated stink bug Halyomorpha halys. If they had not been detected, it is thought this insect would have caused NZ$4 billion in crop damage over the next twenty years. Two years earlier, the Queensland fruit fly Bactrocera tryoni was found in central Auckland. As a consequence, NZ$15 million was spent eradicating it, a small price to pay for the NZ$5 billion per annum it would have cost the horticulture industry had it spread.

Clearly, these critters are to be ignored at our peril! Although the previous New Zealand government introduced the Predator Free 2050 programme, conservation organisations are claiming the lack of central funding and detailed planning makes the scheme unrealistic by a large margin (if anything, the official website suggests that local communities should organise volunteer groups and undertake most of the work themselves!) Even so, this scheme is intended to eradicate alien mammal species, presumably on the grounds that despite their importance, pest invertebrates are just too small to keep excluded permanently - the five introduced wasp species springing to mind at this point.

It isn't just smaller scale animals that are important; and how many people have you met who think that the word animal means only a creature with a backbone, not insects and other invertebrates? Minute and inconspicuous plants and fungi also need considering. As curator at Auckland Botanic Gardens Bec Stanley is keen to point out, most of the public appear to have plant blindness. Myrtle rust is a fungus that attacks native plants such as the iconic pōhutukawa or New Zealand Christmas tree, having most probably been carried on the wind to New Zealand from Australia. It isn't just New Zealand's Department of Conservation that is asking the public to watch out for it: the Ministry for Primary Industries also requests notification of its spread across the North Island, due to the potential damage to commercial species such as eucalyptus. This is yet another example of a botanical David versus Goliath situation going on right under our oblivious noses.

Even without the economic impact, paying attention to the smaller elements within our environment is undoubtedly beneficial. Thinking more holistically and less parochially is often a good thing when it comes to science and technology; paradigm shifts are rarely achieved by being comfortable and content with the status quo. Going beyond the daily centimetre-to-metre range that we are used to dealing with allows us to comprehend a bit more of the cosmic perspective that Neil deGrasse Tyson and other science communicators endeavour to promote - surely no bad thing when it comes to lowering boundaries between cultures in a time with increasingly sectarian states of mind?

Understanding anything a little out of the humdrum can be interesting in and of itself. As Brian Cox's BBC documentary series Wonders of Life showed, a slight change of scale can lead to apparent miracles, such as the insects that can walk up glass walls or support hundreds of times their own weight and shrug off equally outsized falls. Who knows, preservation or research into some of our small-scale friends might lead to considerable benefits too, as with the recent discovery of the immensely strong silk produced by Darwin's bark spider Caerostris darwini. Expanding our horizons isn't difficult, it just requires the ability to look down now and then and see what else is going on in the world around us.