Abstract Detail

Reproductive Processes

Rose-Person, Annika [1], Menges, Eric [1], Smith, Stacy [2].

Fruit Production, Flowering Period, and Pollination of Avon Park Harebells, Crotalaria avonensis (Fabaceae), an Endangered Central Florida Endemic.

Crotalaria avonensis (K.R. Delaney and Wunderlin), Fabaceae, is a state and federally endangered herb endemic to south-central Florida. It is small (<15cm) and occurs naturally on xeric white sands. It exists in only two protected and one unprotected Lake Wales Ridge sites, where its populations are fairly stable. Despite its high annual survival, it has low rates of insect visitation and fruit production. To explore the breeding system of C. avonensis and find reasons for its low fruit production, we observed insect visitation, tracked flower maturation from bud to fruit, performed cross pollinations by hand, and compared genotypes from multiple sites. In 2017, we followed 529 flowers on 76 plants across one population and bagged half of plants to exclude insect pollinators. To determine the importance of cross-pollination, in 2018 we pollinated flowers by hand with four cross types: geitonogamous, within-patch xenogamous, within-population xenogamous, and between-population xenogamous.
Flowering began in March, peaked in April, and continued through June. Flowers opened at 9:30AM, anthers dehisced at 10:00AM, flowers closed in the evening, and flowers remained open for 2-3 days. In all 2017 and 2018 observations we observed a single, generalist bee species, Anthidium maculifrons (Megachylidae) visiting flowers less often than once per hour. Only one fruit of 79 was produced by a pollinator-excluded plant, and 12% of open-pollinated flowers produced fruit. Fruit production was strongly affected by location: one patch produced 99% of fruits though it held only 48% of all flowers. Fruit production facilitated by manual cross-pollination will determine the importance of different levels of outcrossing to the survival and reproduction of C. avonensis, and genetic analyses of leaf and fruit material will describe the population’s genetic diversity. Our results could inform future conservation efforts by underscoring the importance of insect pollinators as well as habitat connectedness, and increase fruit production of this reproductively–challenged plant.

1 - Archbold Biological Station, Plant Ecology Program, 123 Main Drive, Venus, FL, 33960, USA
2 - Archbold Biological Station, 123 Main Drive, Venus, Fl, 33960, United States

Keywords:
Crotalaria
Lake Wales Ridge
Central Florida
reproductive ecology
phenology
Rare plant
pollination.

Presentation Type: Oral Paper
Session: 29, Reproductive Processes II
Location: 111/Mayo Civic Center
Date: Tuesday, July 24th, 2018
Time: 2:30 PM
Number: 29005
Abstract ID:552
Candidate for Awards:None