Stronger pes­ti­cide reg­u­la­tions likely needed to pro­tect all bee species, say stud­ies

The Woolwich Observer - - RURAL CONNECTIONS -


DE­SIGNED TO pro­tect hon­ey­bees fail to ac­count for po­ten­tial health threats posed by agro­chem­i­cals to the full di­ver­sity of bee species that are even more im­por­tant pol­li­na­tors of food crops and other plants, say three new in­ter­na­tional pa­pers co-au­thored by Univer­sity of Guelph bi­ol­o­gists.

As the global hu­man pop­u­la­tion grows, and as pol­li­na­tors con­tinue to suf­fer de­clines caused by ev­ery­thing from habi­tat loss to pathogens, reg­u­la­tors need to widen pes­ti­cide risk as­sess­ments to pro­tect not just hon­ey­bees but other species from bum­ble­bees to soli­tary bees, said en­vi­ron­men­tal sciences pro­fes­sor Nigel Raine, holder of the Re­banks Fam­ily Chair in Pol­li­na­tor Con­ser­va­tion, in a re­lease last week.

“There is ev­i­dence that our de­pen­dency on in­sect­pol­li­nated crops is in­creas­ing and will con­tinue to do so as the global pop­u­la­tion rises,” said Raine, coau­thor of all three pa­pers re­cently pub­lished in the jour­nal En­vi­ron­men­tal En-


With grow­ing de­mands for crop pol­li­na­tion out­strip­ping in­creases in hon­ey­bee stocks, he said, “Pro­tect­ing wild pol­li­na­tors is more im­por­tant now than ever be­fore. Hon­ey­bees alone sim­ply can­not de­liver the crop pol­li­na­tion ser­vices we need.”

Govern­ment reg­u­la­tors world­wide cur­rently use hon­ey­bees as the sole model species for as­sess­ing po­ten­tial risks of pes­ti­cide ex­po­sure to in­sect pol­li­na­tors.

But Raine said wild bees are prob­a­bly more im­por­tant for pol­li­na­tion of food crops than man­aged hon­ey­bees. Many of those wild species live in soil, but sci­en­tists lack in­for­ma­tion about ex­po­sure of adult or lar­val bees to pes­ti­cides through food or soil residues.

The pa­pers call on reg­u­la­tors to look for ad­di­tional mod­els among soli­tary bees and bum­ble­bees to bet­ter gauge health risks and im­prove pro­tec­tion for these species.

“Every­body is fo­cused on hon­ey­bees,” said An­gela Gradish, a re­search as­so­ciate in the School of En­vi­ron­men­tal Sciences and lead au­thor of one pa­per, whose co-au­thors in­clude Raine and SES Prof. Cynthia Scott-Dupree. “What about these other bees? There are a lot of un­knowns about how bum­ble­bees are ex­posed to pes­ti­cides in agri­cul­tural en­vi­ron­ments.”

She said bum­ble­bee queens have dif­fer­ent life cy­cles than hon­ey­bee coun­ter­parts that may in­crease their con­tact with pes­ti­cides or residues while col­lect­ing food and es­tab­lish­ing colonies. “That’s a crit­i­cal dif­fer­ence be­cause the loss of a sin­gle bum­ble­bee queen trans­lates into the loss of the colony that she would have pro­duced. It’s one queen, but it’s a whole colony at risk.”

Like hon­ey­bees, bum­ble­bees for­age on a wide va­ri­ety of flow­er­ing plants. But be­cause bum­ble­bees are larger, they can carry more pollen from plant to plant. They also for­age un­der lower light con­di­tions and in cloudier, cooler weather that de­ter hon­ey­bees.

Those char­ac­ter­is­tics make bum­ble­bees es­pe­cially vi­tal for south­ern On­tario’s green­house grow­ers. “Green­house tomato pro­duc­ers rely on com­mer­cial bum­ble­bee colonies as the only source of pol­li­na­tion for their crops,” said Gradish.

The new stud­ies stem from work­shops held in early 2017 in­volv­ing 40 bee re­searchers from uni­ver­si­ties and rep­re­sen­ta­tives of agro­chem­i­cal in­dus­tries and reg­u­la­tory agen­cies in Canada, the United States and Europe, in­clud­ing Canada’s Pest Man­age­ment Reg­u­la­tory Agency.

“I hope we can ad­dress short­falls in the pes­ti­cide reg­u­la­tory process,” said Raine, who at­tended the in­ter­na­tional meet­ing held in Washington, D.C.

“Given the great vari­abil­ity that we see in the be­hav­iour, ecol­ogy and life his­tory of over 20,000 species of bees in the world, there are some routes of pes­ti­cide ex­po­sure that are not ad­e­quately con­sid­ered in risk as­sess­ments fo­cus­ing only on hon­ey­bees.”

We’re in­creas­ingly de­pen­dent on in­sects such as bum­ble­bees to pol­li­nate our crops, es­pe­cially as our pop­u­la­tion con­tin­ues to in­crease, ac­cord­ing to the new stud­ies.[SUB­MIT­TED]

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