Beyond sanctions: where the costs of nursery pollination are borne

Beyond sanctions: where the costs of nursery pollination are borneNursery pollination mutualisms bring cooperation and conflict into sharp focus: adult insects pollinate flowers, whereas their offspring consume plant tissues.Wu et al. (2026, https://doi. org/10.1111/nph.71476)suggest that the stability of pollination mutualisms depends not only on limiting damage but also on which plant tissues larvae consume and how effectively plants buffer the resulting fitness consequences.Their system also raises the question of when those consequences feed back into population dynamics.Because greater reproductive success in one partner can directly reduce fitness in the other, nursery pollination mutualisms have become important models for understanding how cooperation persists despite conflict (Bronstein, 2001;Sakai, 2002;Dufa€ y & Anstett, 2003).In classic fig, yucca, and Glochidion systems, plants constrain overexploitation through selective abortion, host sanctions, or related forms of partner control (Pellmyr & Huth, 1994;Goto et al., 2010;Jand er & Herre, 2010).Yet, stable interactions need not always depend on penalizing pollinator offspring.In Sambucus sieboldiana, for example, fruit abortion limits further maternal investment while allowing seed-consuming Heterhelus larvae to complete development in fallen fruits (Kawashima et al., 2026).Such cases invite a broader question: can mutualisms also persist by reorganizing where, when, and by whom the costs of cooperation are borne?Wu et al. provide a compelling case study involving the endangered aquatic plant Ottelia jingxiensis.Shore flies (Hydrellia sp.) are primary pollinators of O. jingxiensis, whereas the parasitoid wasp Chaenusa naiadum provides supplementary pollination.Nectarless female flowers resemble nectar-producing male flowers, consistent with imperfect Bakerian mimicry.Shore flies lay eggs predominantly on the persistent calyces of female flowers, but their larvae then migrate down the scapes to submerged leaves, where they feed and pupate; no feeding on ovaries or seeds was observed.Oviposition and larval feeding are therefore spatially decoupled, redirecting offspring damage from reproductive to vegetative tissues.A related tritrophic association involving pollination, leaf mining, and parasitism occurs in Stratiotes aloides (Katzenberger & Zacharias, 2015), but Wu et al. explicitly connect this natural history to mechanisms that may stabilize the mutualism.