The neotropical plant genus Drymonia displays a remarkable variety of floral shapes and colors. One feature that is particularly important to coevolution with pollinators involves the variable shapes and widths of corolla tubes. To evaluate the evolutionary context for changes in corolla shape, we constructed a phylogeny of 50 of the 75 species of Drymonia using molecular markers from plastid (trnK-matK) and nuclear regions (ITS and ETS). Mapping tube shapes on the phylogeny supports open, bell-shaped (campanulate) corolla shape as the ancestral character state for Drymonia, with multiple independent origins of constriction in the corolla tube. Corollas with constrictions take one of three tube shapes: a constricted flower opening and throat with a large, expanded pouch on the lower surface (hypocyrtoid); a constricted flower opening and throat lacking an expanded pouch on the lower surface (urceolate); or a constricted opening and throat where the sides of the corolla appear laterally compressed. Fieldwork demonstrates euglossine bees (mostly Euglossa spp. and Epicharis spp.) visit campanulate corollas while hummingbirds visit corollas that are constricted. Results support eight independent origins of constricted corolla tubes from ancestors with campanulate corolla tubes: 3 hypocyrtoid clades, 3 laterally compressed clades, and 3 urceolate clades (one of which represents a shift from a hypocyrtoid ancestor). Constricted corollas are associated with shifts from the ancestral condition of poricidal anther dehiscence, which presents pollen to pollinators in multiple small doses, to the derived condition of longitudinal anther dehiscence, which presents all pollen to pollinators simultaneously. The association of hummingbird pollination with constricted corolla tubes suggests that narrowing evolved as a barrier mechanism that prohibits the visitation of flowers by bees.

Changes in floral pigmentation can have dramatic effects on angiosperm evolution by making flowers either attractive or inconspicuous to different pollinator groups. Flower color largely depends on the type and abundance of pigments produced in the petals, but it is still unclear whether similar color signals rely on same biosynthetic pathways and to which extent the activation of certain pathways influences the course of floral color evolution. To address these questions, we investigated the physical and chemical aspects of floral color in the Neotropical Gesnerioideae (ca. 1,200 spp.), in which two types of anthocyanins, hydroxyanthocyanins, and deoxyanthocyanins, have been recorded as floral pigments. Using spectrophotometry, we measured flower reflectance for over 150 species representing different clades and pollination syndromes. We analyzed these reflectance data to estimate how the Gesnerioideae flowers are perceived by bees and hummingbirds using the visual system models of these pollinators. Floral anthocyanins were further identified using high performance liquid chromatography coupled to mass spectrometry. We found that orange/red floral colors in Gesnerioideae are produced either by deoxyanthocyanins (e.g., apigenidin, luteolinidin) or hydroxyanthocyanins (e.g., pelargonidin). The presence of deoxyanthocyanins in several lineages suggests that the activation of the deoxyanthocyanin pathway has evolved multiple times in the Gesnerioideae. The hydroxyanthocyanin-producing flowers span a wide range of colors, which enables them to be discriminated by hummingbirds or bees. By contrast, color diversity among the deoxyanthocyanin-producing species is lower and mainly represented at longer wavelengths, which is in line with the hue discrimination optima for hummingbirds. These results indicate that Gesnerioideae have evolved two different biochemical mechanisms to generate orange/red flowers, which is associated with hummingbird pollination. Our findings also suggest that the activation of the deoxyanthocyanin pathway has restricted flower color diversification to orange/red hues, supporting the potential constraining role of this alternative biosynthetic pathway on the evolutionary outcome of phenotypical and ecological diversification.

Woolly monkeys are endangered New World Primates whose natural ecological requirements are known from few sites. This study aimed to investigate the diet of woolly monkeys (Lagothrix lagothricha, Atelidae) to examine how availability determines fruit choice at local and regional scales. We followed two groups of woolly monkeys in the Mosiro Itajura-Caparú biological station in the Colombian Amazon for 16 months, and then compared our observations with previous studies for this and other sites in the Amazon and eastern Andes. We found a high prevalence of fruits in the diet of woolly monkeys in Caparú, which was supplemented with arthropods and leaves. This pattern was observed in all age/sex classes, although juveniles ate more arthropods, and females with dependent young ate more leaves than other classes. We suggest these differences might be due to intragroup competition and particular nutritional requirements in each age/sex class. When comparing the fruit diet composition in Caparú (>190 species) with four other places, we found that Moraceae, Fabaceae, and Sapotaceae were consistently important tree families in the Amazonian sites, and that forest richness is a good predictor of the diet richness. Overall, the results support the hypothesis that woolly monkeys are opportunistic frugivores that are able to adapt their diet to the forest supply and to the temporal variation in resource availability.

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Ongoing research on the systematics of Drymonia (Gesneriaceae) resulted in the discovery of a new species, Drymonia mexicana Clavijo & J.L. Clark of the Gesneriaceae (tribe: Gesnerieae, subtribe: Columneinae). The new species is distinguished by the combination of narrow leaves with large corollas, glabrous leaves adaxially, calyx lobes ovate, and campanulate flowers with the tube slightly recurved ventrally and the limb purple. The new species is endemic to high elevation forests in the the Mexican state of Veracruz. The plant is commonly cultivated, but its introduction from Mexico to the horticultural community is unknown. Here, we describe and illustrate Drymonia mexicana Clavijo & J.L. Clark and present a key to identify the species of Drymonia native to Mexico.