Frugivores? morphological and chemical interaction niches relationship: It is not what it looks like

ROJAS, TOBIAS NICOLAS; RUGGERA, ROMAN; BLENDINGER, PEDRO G.

Ramnagar

Congreso; Seed dispersal in the Anthropocene, 7th Frugivory and Seed Dispersal Symposium; 2020

Consumption of fruits by frugivores could direct the evolution of particular combinations of fruit traits.While frugivores use morphological and chemical fruit traits as cues to make foraging decisions, it isknown that both types of traits are found to be vaguely related in fruits. Interaction niches (INs), or themultivariate space constructed with the traits of interaction partners, is a promising tool to test therelationship strength among fruit traits in the diet. To understand how morphological and chemical INrelate, we constructed IN for morphological and chemical traits using seed-dispersal networks. We i)estimated the relationship between INs via co-inertia analysis and ii) originality (distance from communitycentroid) and uniqueness (distance to closest neighbor) for each niche centroid to evaluate therelationship of these measures with specialization (d′) and number of interaction partners; iii) we fitted aGLM to test the relationship between estimated dispersion of INs with specialization (d′) and number ofpartners; iv) we used two null models to evaluate departures from frequency of interactions and numberof species used by frugivores. We found an important difference when comparing co-inertia ofmorphological and chemical fruit traits (RV = 0.3) with co-inertia of morphological and chemicalfrugivores INs (RV = 0.7). Chemical and morphological originality were negatively related with thenumber of interaction partners (b = −0.5; b = −0.4, respectively). IN dispersions were positively relatedwith the number of interaction partners (b = 0.6, morphological; b = 0.6 chemical). Comparison of nullmodels suggest that frequency of interactions and number of partners are the main shapers of theobserved patterns. Our results show that the number of partners determines the amplitude and position ofthe centroid of the IN and that fruit trait relationships are unlikely to be strengthened by frugivoreforaging decisions. In summary, frugivores consume a combination of fruit traits similar to the communitycentroid, this usage of different food elements could fit with the diet complementarity mechanism.