Functional analysis of the ecological niche of Syphrea sp. (Coleoptera: Chrysomelidae) associated with Plukenetia volubilis L. (Euphorbiales: Euphorbiaceae) in the Peruvian Amazon

Abstract

Abstract. The behavior and within-plant distribution of adult Syphrea sp. was evaluated on Plukenetia volubilis L. (Euphorbiaceae) under a high density planting system near Tarapoto, Peru. Five randomly selected plants per block were observed daily during three 1-hour periods (8:00-9:00, 13:00-14:00 and 17:00-18:00), taking into account the number of adult Syphrea sp. on 10 leaves (upper and lower surfaces) and 10 inflorescences chosen randomly from each plant stratum (lower, middle and higher). A functional analysis considered 45 dimensions that express structural, trophic, and temporal interactions. Niche breadth (B_j) was calculated and dependence of Syphrea sp. population levels with respect to the dimensions considered was determined. Adults of Syphrea sp. trophically and reproductively specialize on young and immature leaves, and perhaps pollen, on the external part of the plant, particularly the upper third. The diurnal behavior of Syphrea sp. is inferred and the beetle’s tendency to aggregate at dusk suggests that feeding is a nocturnal activity. The advantage of using referential structural levels and evaluating populations at dusk in a sampling methodology are discussed.

Key words: Behavior; inca peanut; niche breadth; sampling; within-plant distribution.

DOI: http://dx.doi.org/10.5377/ceiba.v50i1.192