# Different Flowering Strategies Ensure Reproductive Success in Two Coexisting Self‐Incompatible Orchids

## TL;DR

Two self-incompatible orchids use different flowering strategies to achieve similar reproductive success despite sharing pollinators.

## Contribution

The study reveals how divergent flowering strategies can overcome pollination challenges in coexisting self-incompatible orchids.

## Key findings

- Pholidota articulata uses mass-flowering to maximize pollination efficiency with synchronized anthesis.
- Coelogyne prolifera achieves reproductive success through prolonged flowering and reduced pollen discounting.
- Both species achieved moderate natural fruit set rates (21.2%–30.7%), much higher than the typical 2% in self-incompatible orchids.

## Abstract

Orchids have evolved diverse reproductive strategies to overcome pollinator limitation and pollen discounting from geitonogamy, particularly in self‐incompatible species. This study compares two coexisting, self‐incompatible orchids (Pholidota articulata and Coelogyne prolifera) sharing pollinators in an ancient tea garden, examining how their contrasting flowering strategies enhance reproductive success. We conducted a 3‐year study analyzing flowering phenology, floral traits, pollinator behavior, pollinia removal and deposition, the breeding system, and fruit set under both natural conditions and from hand‐pollination treatments. Despite partial flowering overlap, the species exhibited distinct strategies:
P. articulata
employed a mass‐flowering strategy with large floral displays, high nectar rewards, and synchronized anthesis (all flowers per inflorescence opening within ~4 days), while
C. prolifera
adopted a steady‐state strategy with prolonged single‐flower longevity (~13 days) and extended flowering duration (60 days) and consistent but comparatively lower nectar secretion. Both species shared two pollinator species (Vespa velutina and Vespa mandarinia) in 3 years, but the visit frequency was consistently higher for
P. articulata
. Remarkably, 83.3% ± 6.5% of
P. articulata
flowers were pollinated on their first day versus only 4.5% ± 8.6% in
C. prolifera
. Although pollinia removal and deposition peaked during initial anthesis in
P. articulata
,
C. prolifera
showed lower pollen discounting (44.4%) throughout flowering. Despite these differences, both maintained moderate natural fruit sets (21.2%–30.7%) across years, which are substantially higher than the typical 2% reported for most self‐incompatible orchids. Our findings demonstrate that coexisting, self‐incompatible orchids sharing pollinators can achieve comparable reproductive success through divergent strategies:
P. articulata
maximizes pollination efficiency via synchronized mass‐flowering, while
C. prolifera
enhances pollination opportunities through prolonged flowering. This highlights the adaptive diversity of flowering strategies in self‐incompatible orchids facing pollinator limitation and geitonogamy.

This study compares the reproductive strategies of two self‐incompatible orchids, Pholidota articulata (mass‐flowering) and Coelogyne prolifera (steady‐state flowering). Despite differences in pollinator visitation and pollinia transfer efficiency—higher in
P. articulata
—both species achieved similar natural fruit set rates over 3 years. The findings suggest that distinct flowering strategies can equally ensure reproductive success in self‐incompatible orchids.