Food Studies Matter, Meaning, Movement Case Pollinator Ecologies, D Susan Willis Chan and Jennifer Marshman

CASE POLLINATOR SUSAN WILLIS CHAN AND JENNIFER MARSHMAN A OF POLLINATION Susan Willis Chan , is at the School of Environmental Sciences at the University of . is at the Center for Sustainable Food Systems at Wilfrid University . Learning Outcomes After reading and discussing this text , students should be able to SUSAN WILLIS CHAN AND JENNIFER MARSHMAN

Describe the concept of reciprocity as it applies to species relationships . Explain the ongoing reciprocal relationship among humans , crops , and hoary squash bees , and how it is advantageous to partners . Examine why and how healthy native pollinator are important to sustainable food systems . A CASE STUDY IN RECIPROCAL THINKING HUMANS , CROPS SQUASH BEES In this case , we examine the reciprocity that has existed for between humans , crops ( pumpkins , squash , and gourds ) and squash bees , and discuss how that reciprocity can be threatened or strengthened by the actions of humans . Beginning years ago in and again years ago in what is now the American , Indigenous peoples began domesticating wild , especially the wild buffalo gourd ( Buffalo gourds are vines that produce , inedible bitter fruit that were initially used as containers for water , storage , and . Over time , domestication resulted in five species of pumpkin or squash crops grown for their large , edible fruit , and which continue to have cultural importance among nous . domestication can be considered a process between plants and humans that resulted in crop plants . See Smith 1997 Smith 2006 . See Hart et al . pepo , maxima , 552 POLLINATOR ECOLOGY

that are incapable of thriving outside of human and humans that are dependent upon crops for . Modern culture enjoys access to hundreds of of pumpkin or squash crops with different sizes , shapes , colours , growth habits , maturity times , and . The crops are growing in importance globally and are used for food ( fresh vegetables , processing , oil production , snack food ) cultural expression ( ing , en , artisanal crafts , musical instruments ) and purposes . A group of wild pollinators known as squash with wild species and are the most important of these plants across the Americas . What is the relationship between squash bees and humans ?

Unlike most other bee species , the hoary squash bee ( is a truly agricultural bee that has formed a strong , and enduring relationship with humans through their food production systems . In fact , the expansion of the hoary squash bee range across North America is the direct product of the human movement and trade of pumpkin and squash seeds , and subsequent cultivation of the plants by both Indigenous and more recently by settler peoples . Humans , squash crops , and the hoary squash bee thus provide a fascinating example of an intimate , ally beneficial exchange known as reciprocity . Over history , humans moved pumpkin and squash seeds across the continent . Initially this was done by planting and tending them in nous growing systems such as the Three Sisters . These seeds . See Bleed 2006 Landon 2008 . See 2013 . See 2013 2017 2018 et . sub genera species or species . SUSAN WILLIS CHAN AND JENNIFER MARSHMAN 553

are also planted in home and community gardens and , more recently , in large monocultural agricultural systems , all of which have expanded the crops range enormously . However , seed set and fruit production in squash crops is entirely dent upon bees to move pollen from the male to the female that produce fruit ( Figure ) Movement of pollen Pollination happens when pollen grains are transferred from the male anther to the female stigma of . On the stigma , pollen grains grow a pollen tube that allows the genetic material in the pollen to be transferred to the in the ovary , thereby producing fertilized seeds that ensure survival of the species . In some crops , the seeds then stimulate the growth of a fruit . Plants are either , or they may need nation . Cross pollination requires the assistance of a vector ( ally wind or an insect ) to move the pollen from the male anther of one to the female stigma of another . The ment of pollen grains is unintentional . In fact , bees are lated by in this process . For example , the hoary squash bee has a hairy body that picks up pollen as it unintentionally contacts the of a male pumpkin while feeding on the nectar in the . When the bee visits a female for nectar , it lands first on the stigma of that and then walks down to the in the base of the . As it does this , pollen is unintentionally transferred from its body to the sticky surface of the stigma , resulting in pollination . 554 POLLINATOR ECOLOGY

nectary ovule Staminate Flower Pistillate Flower Figure The of crops ( pumpkin or squash ) showing the staminate ( male , pollen bearing ) and pistillate ( female , fruit bearing ) Bees must move the pollen from the staminate to the pistillate for pollination to occur Diagram designed by Susan Willis Chan and drawn by Ann ( crops attract bees by providing copious amounts of nectar and pollen . As the range of crops expanded , hoary squash bees followed , in pursuit of those nectar and pollen resources . As they foraged , hoary squash bees the crops , allowing the plant to produce seeds and develop fruit ( squash or pumpkins ) which humans then vested as a crop ( Figure ) SUSAN WILLIS CHAN AND JENNIFER MARSHMAN

Fruit production via services Humans ' I Present Hoary . Range expansion following crop domestication . via medicines , pollination services and cultural expression Source of Providing ideal pollen and growing conditions crops Figure This diagram shows the reciprocity between hoary squash bees , crops , and humans . Diagram designed by Susan Willis Chan and Jennifer Marshman and drawn by Ann ( What do squash bees use for ?

Like people , squash bees require a healthy diet containing , protein or amino acids , fatty acids , and . Nectar produced in both male and female the carbohydrates and . The pollen , only in the male , provides fatty acids , protein , or amino acids . The of are vital for the survival of squash bees because unlike most bees that forage on a wide range of plants , squash bees are strict dietary specialists , using . See et al . 2001 . et al . 2018 . 556 POLLINATOR ECOLOGY

only pollen to provision the nest cells Where they raise their young ) Figure ) Squash bees are found in North , Central , and South America , and one species , the hoary squash , is found across the tal United States and in Canada as far north as southern and ( Figure ) Interestingly , across most of the present range of the hoary squash bee , there are no Wild ring naturally , making the hoary squash bee entirely dependent upon human cultivation of pumpkin and squash crops for its pollen supply . Figure A hoary squash bee nest in the centre showing the steps involved in the construction of the vertical ( A ) and lateral ( shafts of the nest , the nest cell ( provisioning of nest cells including foraging for nectar and pollen ( and laying of eggs and sealing off the nest cell ( around the outside . Diagram designed by Susan Willis Chan and drawn by Ann ( 10 . See 1964 2014 ) Stephen et al . 1969 . SUSAN WILLIS CHAN AND JENNIFER MARSHMAN 557

The importance of hoary squash bees in pumpkin and squash production Because they have separate male and female , pumpkin and squash crops are entirely dependent on insects for tion and ultimately seed and fruit production . As such , hoary squash bees are a vital part of our agricultural landscape . They are the most abundant visitors to crops and are ubiquitous on farms growing pumpkin and squash in eastern North America . Their populations are reliably abundant from year to year , and the timing of their foraging activity corresponds well to the crops pollination window ( to daily , from to ) Hoary squash bees are active on the crop as soon as they open at dawn , when pollen supplies are greatest , and they remain active until the crop wilt at noon . Seasonally , the bees emerge from their natal ground nests around the time that pumpkin and squash crops begin to bloom and begin to forage on the immediately ( Figure ) The bees unique behaviour and biology also contribute to the tightness of their relationship with crop . Besides foraging on the crop , hoary squash bees also mate on the , and males and unmated females sleep in the wilted during the afternoon and evening after the tar resources are exhausted . Other aspects of the biology of the hoary squash bee are linked to pumpkin and squash crops . To effectively collect pollen , which is spiny and oily and not favoured by other bees such as the Western honey bee or bumble bees , hoary squash bees have evolved specialized hairs ( scopa ) on their hind legs . 558 POLLINATOR ECOLOGY

. adult . Figure The lifecycle of the hoary squash bee in , Canada showing how it coincides with in the crops that the bee depends upon for its pollen supply . It takes one year for a hoary squash bee to develop from eg to adult . Diagram designed by Susan Willis Chan and drawn by Ann ( Unlike the familiar Western honey bee , which is a social insect that lives in a colony with tens of thousands of other bees , squash bees are solitary . This means that each mated female builds her own nest in the ground ( often within or close to pumpkin or squash crops ) and raises her own offspring within cells in that nest ( Figures and ) However , like people in an urban , many of these bees will live close to each other , creating dense , expanding nesting , sometimes with thousands of individual nests in a small area . this video of a hoary squash bee nesting aggregation . SUSAN WILLIS CHAN AND JENNIFER MARSHMAN

12 . If large , stable populations of wild bees , such as the hoary squash bee , are maintained on farms , they will provide reliable , free services to crops , reducing an overreliance on honey bees , which are under increasing pressure from pests , diseases , and losses . What is the threat to hoary squash bees ?

Known threats to bees generally include habitat loss , a changing climate , pests and diseases , pesticide use , and the interaction among these threats . For the squash bee , we will focus on use . The hoary squash bee , because of its close association with pumpkin and squash crops across most of its range , may be at risk of exposure to insecticide residues in agricultural soil if those crops are treated with insecticides to control insect pests . Indeed , exposure to crops treated with a common insecticide causes hoary squash bee populations to construct fewer nests and harvest less pollen , resulting in greatly reduced offspring production . This puts crop pollination at risk over the long term . This is ironic because it is precisely the hoary squash bee enduring relationship with human crop cultivation that has supported the bees large and range expansion . In fact , by applying this insecticide to soil , We are causing harm to the very pollinators that help with successful food crop production , thereby harming ourselves . An Ethic of Reciprocity Reciprocity describes a mutually beneficial relationship among organisms or groups . The reciprocity of the squash bee relationship is obvious , and a salient See Willis Chan 2021 . 560 POLLINATOR ECOLOGY

example of what the best ( and worst ) outcomes can be for all partners in , crops . As such , it is a reminder of the ways in which human actions can affect or relationships among bees that pollinate food crops for humans and other living things . Reciprocity implies that the choices humans make that have a positive or negative impact on pollinators also have a positive or negative impact on human . Although bees and crops may have little agency to protect themselves , humans can act to protect bees and their own crop yields in several simple but effective ways . This can be illustrated within growing systems . First , growers can acquaint themselves with hoary squash bees . These bees are easy to identify on pumpkin and squash , rarely sting , and are considered to be quite endearing . about the bee is readily available online , including , videos , and diagrams . A greater awareness of this bee , and familiarity with its behaviour , biology , and ecology , can help strengthen this important relationship through respect , empathy , and understanding . A example of this enduring and endearing relationship is found on Strom Farm Bakery near , The have understood the importance of hoary squash bees for their pumpkin growing enterprise . They have educated selves about the nesting behaviour of hoary squash bees and have allowed hoary squash bees to build nesting in lawns outside their cropping areas . In these lawns , the nests and the female bees who build them are protected from tillage and sure to agricultural pesticides used on the crops . As a result , the nesting on that farm are expanding , ensuring nation services from the bees into the future . SUSAN WILLIS CHAN AND JENNIFER MARSHMAN 561

Next , growers can choose not to apply systemic pesticides to soil to avoid the demonstrated ill effects on hoary squash bees . On Farm near Lindsay , the farm owners have learned about the effects of on hoary squash bees by supporting research activities on their farm . As a result , they have stopped using these pesticides in their production practices because they were shown to reduce hoary squash bee nesting and foraging behaviour , resulting in declining populations . Other growers such as Lunar Rhythm Gardens near , have adopted alternative approaches to pesticide use including physical barriers against pests , such as row covers . The row covers are applied after planting , and are removed once flowering begins . This gives the hoary squash bees access to the flowers . Alternately , trap crops can be used to draw insect pests away from the cash crop , or pesticides can be used , which are applied only in reaction to pest pressure using grated pest management ( principles . CONCLUSION Clearly , maintaining a healthy reciprocal relationship among humans , crops , and hoary squash bees is advantageous to all partners . Humans gain reliable access to fruit ( pumpkin or squash ) or seeds for food , medicine , or cultural expression . crops are planted widely and tended by humans and receive the pollination services that they need to set seed and reproduce . Hoary squash bee populations have reliable sources of the only pollen that they feed to their young , as well as mating and sleeping sites . As the members of this relationship with the most agency , humans hold the responsibility to , value , and protect the integrity of this reciprocal ship for the benefit of all . 562 POLLINATOR ECOLOGY

Discussion Questions List and explain some of the reasons is it to lump together all pollinators into one group , using the squash bee as an illustrative example . Considering the information presented in this case , what are some of the problems associated with an on the domesticated honey bee as a primary pollinator of food crops ?

Explain the reciprocal relationship among humans , crops , and the hoary squash bee to illustrate the nature of reciprocity in food systems . How can human action negatively or positively affect our reciprocal relationship with crops and hoary squash bees ?

How can reciprocity drive positive actions ?

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ing exposure to a insecticide treated crop ( pepo ) Sci Reports 11 566 POLLINATOR ECOLOGY