Abstract
PREMISE: Species of Apocynaceae are pollinated by a diverse assemblage of animals. Here we report on the first record of specialized cockroach pollination in the family, involving an endangered climbing vine species, Vincetoxicum hainanense in China. Experiments provided direct proof of cockroach pollination and compared the effectiveness of other flower visitors.
METHODS: We investigated the reproductive biology, pollination ecology, pollinaria removal, pollinia insertion, and fruit set following single visits by the most common insects. In addition we reviewed reports of cockroaches as pollinators to other plants. Finally we analyzed the known pollination systems in Vincetoxicum in a phylogenetic context.
KEY RESULTS: The small, pale green flowers of V. hainanense open during the night. The stigma has high receptivity in the first 3 days of blooming. The flowers are not autogamous, however, flowers are self-compatible. Flower visitors include beetles, flies, ants and bush-crickets, but the most effective pollinator is the cockroach Blattella bisignata, which is the only visitor that carries pollen between plants. Less frequent and effective pollinators are ants and Carabidae. Cockroach pollination is embedded in a genus predominantly pollinated by flies, moths and wasps.
CONCLUSIONS: Globally, only 11 plant species are known to be cockroach pollinated. These plants possess a range of floral features, with some similarities and some differences. Thus it is difficult to define a “cockroach pollination syndrome”. One commonality is that flowers are often visited by insects other than cockroaches, such as beetles, that vary in their significance as pollinators. Cockroach pollination is undoubtedly more widespread than previously thought and requires further attention.
KEY WORDS: Apocynaceae; breeding system; cockroach pollination; floral biology; Vincetoxicum hainanense; pollination system; pollinator; pollinaria removal; pollinia insertion; reproductive biology.
METHODS: We investigated the reproductive biology, pollination ecology, pollinaria removal, pollinia insertion, and fruit set following single visits by the most common insects. In addition we reviewed reports of cockroaches as pollinators to other plants. Finally we analyzed the known pollination systems in Vincetoxicum in a phylogenetic context.
KEY RESULTS: The small, pale green flowers of V. hainanense open during the night. The stigma has high receptivity in the first 3 days of blooming. The flowers are not autogamous, however, flowers are self-compatible. Flower visitors include beetles, flies, ants and bush-crickets, but the most effective pollinator is the cockroach Blattella bisignata, which is the only visitor that carries pollen between plants. Less frequent and effective pollinators are ants and Carabidae. Cockroach pollination is embedded in a genus predominantly pollinated by flies, moths and wasps.
CONCLUSIONS: Globally, only 11 plant species are known to be cockroach pollinated. These plants possess a range of floral features, with some similarities and some differences. Thus it is difficult to define a “cockroach pollination syndrome”. One commonality is that flowers are often visited by insects other than cockroaches, such as beetles, that vary in their significance as pollinators. Cockroach pollination is undoubtedly more widespread than previously thought and requires further attention.
KEY WORDS: Apocynaceae; breeding system; cockroach pollination; floral biology; Vincetoxicum hainanense; pollination system; pollinator; pollinaria removal; pollinia insertion; reproductive biology.
| Original language | English |
|---|---|
| Journal | American Journal of Botany |
| Publication status | Accepted/In press - 17 Jun 2020 |
Keywords
- Pollination biology
- Botany