Reward partitioning in Capparis spp. along ecological gradient

Area of Science:

• Botany
• Ecology
• Entomology

Background:

• The genus Capparis, specifically the spinosa section, is represented in Israel by three distinct taxa.
• Understanding plant-pollinator interactions is crucial for ecological studies and conservation efforts.

Purpose of the Study:

• To investigate the pollinator diversity and efficiency across three Capparis taxa in Israel.
• To analyze the floral rewards offered by these taxa and their relationship with pollinator preferences and habitat type.

Main Methods:

• Field observations were conducted to identify and quantify pollinators visiting the three Capparis taxa.
• Floral rewards, including pollen quantity and nectar sugar concentration, were analyzed for each taxon.
• Pollinator visitation frequency and efficiency were assessed in relation to the provided rewards and habitat.

Main Results:

• Hawkmoths were primary pollinators for C. spinosa var. aravensis and C. ovata, but rarely visited C. spinosa var. aegyptia.
• Bees (Proxylocopa and other diurnal bees) were abundant across all three taxa nationwide.
• Capparis taxa offered varied rewards: C. spinosa var. aegyptia provided abundant pollen and less nectar, while C. spinosa var. aravensis and C. ovata offered less pollen but higher nectar sugar concentration.

Conclusions:

• Pollinator efficiency varies significantly among the three Capparis taxa, influenced by specific pollinator groups and floral rewards.
• Floral reward strategies (nectar vs. pollen dominance) are adapted to different habitats (Mediterranean vs. arid), irrespective of the plant's taxonomic origin.
• The findings highlight the intricate relationship between Capparis species, their pollinators, and environmental factors in Israel.