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The Ox Eye liana (Family Fabaceae: Papilionoideae) is found from Nicaragua to South America, and is widespread in Costa Rica from 500-2,000 m elevation (Zuchowski & Forsyth 2005). This is one of seven Mucuna species in Costa Rica and is most common at high elevations and forest edges (Gargiullo et al. 2008). Its common name in Spanish, picapica, roughly translates to “itchitch” and refers to the urticating, itchy hairs that cover the flowers and fruit pods (Zuchowski & Forsyth 2005). This woody liana has large trifoliate leaves with entire margins and spaced secondary veins, and a swollen pulvinus (Gentry & Vasquez 1996). It also has asymmetrical veins and leaflets. Because it is a liana, it grows spiraled around other plants in the area. The Ox Eye inflorescence contains zygomorphic, pealike flowers with 10 stamens, and the greenish, cream-colored flowers are arranged in a spiral in groups of three on the stem (Smith et al. 2004, Zuchowski & Forsyth 2005). This hanging chandelier-like cluster on the liana is found on the end of the peduncles, which can be of varying lengths up to 10m (Agostini et al. 2006).
Although most members of the Papilionoideae subfamily are pollinated by bees, this genus is pollinated by bats; specifically, the Ox Eye is pollinated by the nectivorous small bat Glossophaga soricina (Agostini et al. 2011). Glossophaga finds the flowers using an acoustic nectar guide that reflect echolocation signals back to the bat so it can more easily find the flower, a technique seen in several Mucuna species (von Helversen & von Helversen 1999). The Ox Eye has also been recorded as being pollinated by the omnivorous bat Anoura caudifer and Hylonycteris species, though not as often as G. soricina (Sazima et al. 1999, Zuchowski & Forsyth 2005). Agostini et al. (2006) found that as the bats probe for nectar, the flowers project pollen onto the pollinators in an explosive fashion after pressure has been applied to the flower. When this flower opening mechanism is activated, the flower immediately ceases nectar production to begin fruit development (Agostini et al. 2011). Some bees and hummingbirds have been observed as “nectar robbers” that drill holes and steal nectar from the flower during the day without pollinated the flower.
Fruits of the Ox Eye are large, dehiscent brown pods (about 15cm long) with a wrinkled appearance, covered in irritating golden hairs (Zuchowski & Forsyth 2005). Each pod contains around three large black seeds. Cental American agoutis (Dasyprocta punctata) act as both seed predators and seed dispersers for the Ox Eye by either immediately eating the seed or cache the seeds to eat later and forget after burying them (O’Dell 2000). The seeds also contain toxic compounds to deter parasitism by bruchid beetles (O’Dell 2000, Smith et al. 2004).