Seirian Sumner - Endless Forms: The Secret World of Wasps

Seirian Sumner is a Professor of Behavioural Ecology at University College London, where she studies the ecology and evolution of social insects. She has published over 70 papers in scientific journals, and has received numerous awards for her work, including a LOral For Women in Science Award, a Points of Light Award from the UK prime minister, and a Silver Medal from the Zoological Society of London. She is a Fellow and Trustee of the Royal Entomological Society and co-founder of the citizen science initiative Big Wasp Survey. Endless Forms is her debut work of non-fiction for a general audience. She lives in Oxfordshire, England with her husband and three children.

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Sierian Sumner asserts the moral right to be identified as the author of this work

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Source ISBN: 9780008394479

Ebook Edition May 2022 ISBN: 9780008394493

Version: 2022-04-22

Part Seven

There are certain flowers that may be justly called wasp-flowers, because the head of the wasp and the cup of the flower fit each other so prettily.

Margaret Morley, Wasps and Their Ways (1900)

Prelude

To many people the term insect is synonymous with pollinator. This implicit link is driven by the wide research and public focus on the importance of insects such as bees as pollinators, their contributions to the pollination of human-cultivated crops, and the recent concerns about how global declines in insect populations might affect these services. Over 75 per cent of crops worldwide directly depend on insects as pollinators, making insect pollination worth over $250 billion per year globally.

Without insect pollinators we would lose between 5 and 8 per cent of all crop production. This might not sound huge, but in the last five decades our pollinator-dependent global agriculture has grown twice as quickly as agriculture that does not depend on pollinators. To people like me in a country like the UK, loss of pollinators would present some annoying first-world sacrifices, like no morning coffee or chocolate treats, no rapeseed oil with which to cook my kids an evening meal and no comforting bedtime hot cocoa.

On a more serious level, without insect pollination the economic and health costs would be catastrophic. Pollinator-dependent crops are sources of important micronutrients including vitamins A and C, folic acid, calcium and fluoride. Without these nutrients there would be surges in global levels of preventable diseases. For example, scientists estimate that pollinator losses could result in around 1.4 million additional deaths due to heart disease.

The effects of pollinator losses would be felt most acutely by people living in poorer regions and who are already challenged by malnutrition. Areas like western, northern and central Africa have been identified as especially vulnerable, because millions of people there rely on effective pollinator networks to sustain family-scale smallholdings. Beyond food, we also have insect pollinators to thank for the production of biofuels (from things like sunflowers, soybeans and oilseed rape), food for livestock, construction materials, medicines and culturally important materials for musical instruments, arts and recreational activities, including the flower-rich green spaces that we enjoy. Pitched alongside malnutrition and starvation, these latter commodities might seem trivial, but there is growing evidence for the positive direct effects that pollinators have on things that influence our wider wellbeing, mental health and happiness.

The importance of pollinators to wild ecosystems is even harder to quantify: more than 90 per cent of tropical flowering plant species and around 78 per cent of temperate plant species rely at least in part on animal pollination. Scientists are still struggling to work out how to factor these commodities into estimates for the value of insect pollinators because the economic value of natural ecosystems is less tangible. Even more elusive are the contributions made by pollinating insects that are not bees, hoverflies or butterflies. Lets look at the relationship between wasps and plants, and how their contributions to pollination are missing from current valuations of insects in ecosystems.

I

If I asked you to name a pollinating insect, my hunch is that it wouldnt be a wasp. It would most likely be a bee. Bees certainly deserve a good share of the pollinator footlights fame-list: more than 90 per cent of the leading 107 global crop types are pollinated by bees. The reason why bees are so great at pollinating is because, unlike almost any other insect, bees go out of their way to collect pollen: some (the corbiculate bees) have evolved specialist pollen-collecting, big fat rear legs (pollen baskets) and they also often have hairy bodies which become easily coated in pollen dust.

The western honeybee Apis mellifera is the most versatile of the pollinators and it is the species that we have our longest cultural relationship with. Although originally native to Eurasia and Africa, Apis mellifera now has a cosmopolitan distribution, having been introduced almost worldwide. In the last five decades the number of honeybee hives has increased globally by 45 per cent. The honeybees popularity should come as no surprise: they are easily managed, relatively unfussy about the flowers they visit, and have the double benefit of being a producer (of honey and wax) as well as a servicer (as pollinator).

For rural communities in at least 50 countries around the world, beekeeping has deep cultural roots, with honey products providing livelihood security and helping alleviate poverty. In parts of Europe and the USA, bee-farming is industrial in scale: famously, thousands of honeybee hives are trucked tens of thousands of kilometres across continents to follow seasonal changes in pollination of crops, from almonds and alfalfa to broccoli and squash. Similarly, hives are shipped between countries to exploit peak bloom periods and maximise honey yields. In other words, honeybees are worked hard for their honey and their pollinating services. And they are exemplary employees.

But theres a cost to this. Such intensive honeybee management is threatening native pollinator-plant networks. A recent study compared wild pollinator communities with and without honeybees in Teide National Park in Tenerife, one of the Canary Islands. Up to 2,700 beehives are moved to the park every year to take advantage of spring blooms for prime honey production. In a year when the beehives were not introduced to the park, scientists conducted an experiment to compare spring pollinator-plant communities with and without honeybees.