This species is uncommon, but has been found on a wide range of Passiflora subgenus Decaloba species, including P. biflora, P. lobata, P. arbelaezii and P. costaricensis. The latter two species are highly cyanogenic, suggesting that M. chontalensis may be more tolerant of HCN release than many other flea beetles. Alternately, it may possess some other mechanism to neutralize and prevent HCN release. M. chontalensis is usually found in shady environments. Examination of specimens in D. Furth collection, US National Museum, revealed much greater abundance of this species at higher elevations. Perhaps the La Selva population consists of stragglers drifting down from the nearby mountains where an alternative host may be available, P. lancearia.

This species may be very long-lived. I collected 2 adults from the wild on 2 December, 2013, and at least one was still alive in an isolation cage (with a potted P. biflora) 83 days later. Like M. violacea, this species is readily recognizable in museum collections by the shiny black band across the abdomen, even when the red coloration is lost.

I have not found eggs or larvae of this species, but predict they will be similar to Monomacra violacea.