Functional redundancy in invertebrate pollinator-predator networks supports conservation of a threatened North American orchid: a case study of Platanthera integrilabia

Invertebrate pollination and herbivory dynamics of rare orchids are poorly documented. This is particularly true for species of Platanthera, complicating efforts to conserve rare species within this widespread genus. We report five new pollinators and several associated insect interactions for the U.S. federally threatened white fringeless orchid (Platanthera integrilabia) based on 3–18 years of direct field observations, including remote (Raspberry Pi) cameras, across seven Kentucky wetlands. We describe sphinx moth pollination for the first time in this species: Hyles lineata, Eumorpha pandorus. Dolba hyloeus, and Hemaris diffinis at open wetlands, and documented the northern cloudywing skipper butterfly (Thorybes pylades) in semi-open forested wetlands. Habitat characteristics, including canopy cover and floristic diversity, strongly influenced pollinator presence; orchid population size and proximity to open corridors and diverse herbaceous vegetation predicted sphinx moth pollinator presence and frequency. Across sites and years, multiple diurnal and nocturnal Lepidoptera visited or pollinated P. integrilabia, with differing pollinia transfer efficiency and visitation frequency rates, indicating functional redundancy and response diversity that buffers reproduction when individual species fluctuate, a lower risk strategy than reliance on a single specialist. Numerous other visitors (butterflies, bees, hummingbirds) foraged on flowers without carrying pollinia. Invertebrate predators (spiders, praying mantids), and seven species of invertebrate herbivores (including aphids, weevils, caterpillars) were also documented. Among these, aphids are suspected contributors to arrested inflorescence development, potentially lowering fecundity. By documenting these interactions, we provide conservationists and land managers actionable insight for improving the viability of P. integrilabia and other native orchids threatened with extinction.