Chrysophyllum marginatum (Sapotaceae): Generalist pollination and cryptic gynomonoecious

Abstract

Chrysophyllum (Chrysophylloideae, Chrysophylleae) is the second largest genus in the Sapotaceae. Studies of pollination ecology in this genus are non‐existent, although there are records of entomophily for this family. Considering the lack of detailed studies on pollination ecology and sexual systems in Chrysophyllum species, we investigate the floral morphology and biology and floral visitors of Chrysophyllum marginatum to verify which sexual system is present in the studied population and whether flowers of this species are visited and pollinated by different insect groups. The population of C. marginatum has weak and cryptic gynomonoecy because the plants produce a low percentage of functionally pistillate flowers (4.2%) and these flowers appear to be perfect flowers (hermaphrode). Flowers of C. marginatum are phenotypically, ecologically and functionally generalist because: (a) they are actinomorphic, open and not restrictive in terms of access to floral resources; (b) they are visited by 26 species of insects that are potential pollinators; and (c) among these species several groups can be effective pollinators, mainly bees and flies, according to the most effective pollinator principle. We consider bees and flies to be the main pollinator group of C. marginatum, due to their high visitation rate, richness and intrafloral visiting behavior, and because they especially forage among plant individuals and are able to promote xenogamy. Nectaries were found in the ovary base and osmophores in the petal margins, as floral attractants. For Chrysophyllum, this is the first record of gynomonoecy and for the family this is considered the second record. Chrysophyllum marginatum has generalist and entomophilous pollination, as recorded in other Sapotaceae Neotropical species.

Reassessment of generic boundaries in Neotropical Chrysophylloideae (Sapotaceae): Eleven reinstated genera and narrowed circumscriptions of Chrysophyllum and Pouteria

“…reported dioecy in both these species since the female flowers have no stamens, but he did not indicate whether the unisexual and bisexual flowers were borne on separate individuals or the same plant. The sexual system of these taxa remains unknown, but the possibility of dioecy is interesting since Chrysophyllum displays gynomonoecy (Sigrist & al., 2021) and Micropholis exhibits dioecy (Terra- Araujo & al., 2012). Our findings support the conclusions of Faria & al.…”

Pollination biology of a rare serpentine plant, Japonolirionosense (Petrosaviaceae)

“…The nectar of both Japonolirion and Petrosavia is exposed (Takahashi et al 1993, Rudall 2002, this study), making it easily accessible to flower visitors. The flower visitors of the two genera include insects such as ants, bees, flies, and parasitoid wasps, which are frequently found in other plant species with exposed nectar (Sigrist et al 2021, Manrique Valderrama et al 2022). Japonolirion and Petrosavia may, therefore, be adapted to pollination by insects that feed on exposed nectar.…”