Conserving All the Pollinators: Variation in Probability of Pollen Transport among Insect Taxa

Abstract

As concern about declining pollinator populations mounts, it is important to understand the range of insect taxa that provide pollination services. We use pollen transport information acquired over three years in two habitats at Badlands National Park, South Dakota, USA, to compare probabilities of pollen transport among insect taxa and between sexes of bees. Sampling was conducted on 1-ha plots, eight in sparse vegetation (May-October samples; N = 74 surveys) and 12 in wheatgrass prairie vegetation (June-July samples; N = 87 surveys). Insects contacting reproductive parts of flowers were netted, placed individually into tubes charged with ethyl acetate, then transferred to individual labeled glassine envelopes for transport to the lab. Pollen was removed from insect bodies with fuchsin jelly cubes which were then mounted on microscope slides for identification. The probability of taxa transporting only conspecific pollen (with respect to the plant species upon which it was collected), mixed pollen, only non-conspecific, or no pollen was estimated with multinomial logistic regression. Bees were the most commonly captured flower visitor and carried by far the most pollen (females >10× as much as males), but they were most likely to carry mixed pollen loads. Flies, beetles, and wasps were also common flower visitors and beetles were most likely to carry only conspecific pollen. Ants and diurnal lepidopterans were unlikely to carry any pollen. Bees, beetles, flies, and wasps varied in the timing and habitat in which they were most likely to transport pollen, suggesting that all played a role in providing robust pollination services.

Toward Improving Pollinator Habitat: Reconstructing Prairies with High Forb Diversity

“…The increase we document in mean C in higher-richness plots suggests these also may improve habitat for butterflies and other pollinating insects. Denning and Foster (2018b) observed a correlation between forb and bee diversity on their tallgrass prairie study sites, so the greater forb richness we observed in our extra-high plots may prove attractive to bees, which are arguably among the most important pollinating insects (Larson et al 2018b). Adding forb species was effective in our study, in that these species established, persisted, and even dispersed to other plots during the 10 y since planting.…”

Coflowering invasive plants and a congener have neutral effects on fitness components of a rare endemic plant

“…Similarly diverse and unspecialized flower-visitor assemblages were found for Eriogonum pelinophilum, a rare perennial buckwheat found in restricted habitats in western Colorado (Tepedino et al, 2011). Further, the numerous males collected on E. visheri would have primarily been visiting the flowers for nectar and would be expected to carry less pollen than females (Larson et al, 2018).…”

Pollinators limit seed production in an early blooming rare plant: evidence of a mismatch between plant phenology and pollinator emergence

“…Nearly 88% of plants globally rely on animals (mostly insects) to transport pollen among plants (Ollerton et al 2011). Most pollinators visit flowers to drink the nectar and pollen sticks to their bodies while they drink, but bees actively collect pollen to feed their young, which may explain why they are prolific pollinators in most ecosystems (Larson et al 2018). When we observe a bee visiting a flower, that bee may be drinking nectar, collecting pollen or both.…”