Five pollination guilds of aroids (Araceae) at Mulu National Park (Sarawak, Malaysian Borneo)

Abstract

ABSTRACT This study aimed to investigate the floral biology and pollinators of 21 aroid species representing 10 genera at Mulu National Park to ascertain if additional guilds were active in this, one of the most florally diverse plant families in the tropics. Extensive field observations on floral biology, including inflorescence development stages, floral traits, and pollinator rewards, identification of pollinators and their behaviour(s), were undertaken. Reproductive success was calculated and compared among taxa. Anthetic duration of unisexual-flowered taxa was 1–4 days, compared with 4–18 days in bisexual-flowered taxa. Floral traits such as floral odour, restricted access to the female zone during pistillate anthesis, presence of sacrificial floral tissues and anthetic duration affected the type and number of pollinators. Diptera are the most likely pollinators for Aglaonema, Alocasia, Pothos and species of Schismatoglottideae; Coleoptera are the pollinators for Amorphophallus, Anadendrum (together with thrips), Homalomena, Lasia and Schismatoglottis; Thysanoptera (thrips) is one of the pollinators for Anadendrum; Hemiptera (Miridae) pollinates Lasia spinosa and Pothos insignis. Hymenoptera (Apidae) are pollinators for Alocasia sarawakensis and Amorphophallus hewittii. Alocasia sarawakensis, Amorphophallus hewittii, Anadendrum sp., Homalomena (all species), Lasia spinosa, Pothos insignis and Schismatoglottis (all species) apply a generalist pollination system, while Aglaonema nitidum and A. simplex, Alocasia princeps, Amorphophallus julaihii, Phymatarum borneense and Pothos scandens are specialists.