Revista de Biología Tropical ISSN: 0034-7744 [email protected] Universidad de Costa Rica Costa Rica Ospina-Torres, Rodulfo; Montoya-Pfeiffer, Paula María; Parra, Alejandro; Solarte, Víctor; Tupac Otero, Joel Interaction networks and the use of floral resources by male orchid bees (Hymenoptera: Apidae: Euglossini) in a primary rain forests of the Chocó Region (Colombia) Revista de Biología Tropical, vol. 63, núm. 3, septiembre, 2015, pp. 647-658 Universidad de Costa Rica San Pedro de Montes de Oca, Costa Rica Available in: http://www.redalyc.org/articulo.oa?id=44939781008 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Interaction networks and the use of floral resources by male orchid bees (Hymenoptera: Apidae: Euglossini) in a primary rain forests of the Chocó Region (Colombia) Rodulfo Ospina-Torres1, Paula María Montoya-Pfeiffer1, Alejandro Parra-H. 1,2, Víctor Solarte1 & Joel Tupac Otero3,4 1. Laboratorio de Investigaciones en Abejas LABUN, Departamento de Biología, Facultad de Ciencias, Universidad Nacional de Colombia, sede Bogotá; [email protected], [email protected], [email protected] 2. Ecologia e evolução de abelhas, Departamento de Biologia, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo; [email protected] 3. Grupo de Investigación en Orquídeas, Ecologia y Sistemática Vegetal, Departamento de Ciencias Biológicas, Universidad Nacional de Colombia, sede Palmira; [email protected] 4. Instituto de Estúdios Ambientales IDEA, Universidad Nacional de Colombia, sede Palmira; [email protected] Received 13-VIII-2014. Corrected 07-II-2015. Accepted 09-III-2015. Abstract: Orchid bees are important keystone pollinators from the Neotropics. With the aim to study the rela- tionships between orchid bees and their nectar and aromatic host species, we made systematic samplings of males across two conservation areas in the biogeographic Chocó Region of Colombia. We used chemical baits to collect 352 male bees during five months. The pollen attached to their bodies was extracted for palynological identification and to estimate interaction networks. The euglossine community consisted of at least 22 species including Eg. maculilabris, Eg. orellana, Eg. championi and Eg. ignita. The male bees were associated with 84 plants but depended on a small group of them (Peperomia spp. and Anthurium spp, as well as species of Solanaceae, Ericaceae and Malpighiaceae) which were widely distributed across the altitudinal gradient, and were available through the year. The resulting interaction networks revealed a typical nested pattern usually found in plant-pollinator interactions, with several rare bee and plant species interaction with a small group of generalist bees and plant species. Albeit, we found variation within networks related to species composition. Such variation may be a consequence of specific differences in plant flowering phenology. Rev. Biol. Trop. 63 (3): 647-658. Epub 2015 September 01. Key words: community ecology, plant-insect relationships, Rio Ñambí Natural Reserve, pollinators, interaction networks; mutualisms. Plant-pollinator interaction had been the plants are more diverse than in temper- focused at the species level (Duque-Buitra- ate areas. For example, the cloud forest of La go, Quintero, & Otero, 2014); nevertheless, Planada on the Western slope of the Andes more recently community level pollination in the South of Colombia contain more than studies had been explored on a broader per- 890 vascular plant species (Vallejo, Samper, spective using interaction networks (Fontaine, Memdoza, & Otero, 2004). This high plant Dajoz, Meriguet, & Loreau, 2005; Vázquez diversity may be associated with a concordant & Aizen, 2004). Plant-pollinator networks are requirement of pollinators producing complex now known to be asymmetric in their special- plant-pollinator networks. ization affecting the community organization Male orchid bees (Apidae: Euglossini) are and ecosystem sustainability (Bascompte, Jor- important pollinators of lowland Neotropics dano, Melián, & Olesen, 2003; Fontaine et al., Angiosperm (Ackerman, 1985; Roubik & Han- 2005; Vázquez & Aizen, 2004). In the tropics, son, 2004). The importance of male Euglossini Rev. Biol. Trop. (Int. J. Trop. Biol. ISSN-0034-7744) Vol. 63 (3): 647-658, September 2015 647 bees has been documented for many plant fam- predominantly by a sub-Andean cloud forest ilies in different ecological and evolutionary which is currently subjected to various defor- contexts (Ramírez, Dressler, & Ospina, 2002); estation processes. Precipitation in the region bees visited nine plant families as aromatic is the highest in Colombia (7 100 mm per year) resources and 35 families for nectar, pollen with little seasonality, but a wetter season does and/or nesting materials. They also collect food occur between January and July. The annual resources such as nectar with their long tongues average temperature is 24 °C with small varia- (a characteristic of the tribe) playing a determi- tions across the altitudinal gradient (IDEAM, nant ecological and physiological role (Borrell, 2009; Gutiérrez, Carrillo, & Rojas, 2004; Sol- 2004; Borrell & Krenn, 2006). The proboscis arte, 2005). length could have preponderant implications The reserve has an extremely high floris- in niche segregation, due to its capacity for tic diversity and also high level of endemism. accessing deep corollas and the pressure gener- Hilty (1980) and Salaman (2001) described ated across the mouth parts during nectar intake it as an evergreen forest lacking predomi- (Borrell, 2006; Parra-H & Nates-Parra, 2012). nant deciduous periods. Vegetation develops Palynological studies of male euglossine floral in slopes up to 35 degrees with a canopy that preferences, could provide a more detailed reaches 25 to 30 m and high level of epiphyt- assessment of plant species spectrum pollinated ism. Franco-Rosselli, Betancur and Fernández- by these bees, since both males and females Alonso (1997) registered 205 species, 122 collect nectar from the same plant species genera and 59 families. Nearly a third part of and especially because there is no systematic the plant families are represented by a single methodology for female sampling (Ackerman, species; the most species-rich families in the 1985). This kind of approaches should suggest region are: Rubiaceae, Araceae and Melasto- general patterns in both, spatial and temporal mataceae and the genera with most species use of resources. were Anthurium, Psychotria, Philodendron, Here we document bee-plant relationships Piper, Inga and Miconia. by analysing pollen attached to male bod- We chose different sampling points in ies and describe the intra and inter-specific two different areas of the reserve: “Ñambí” variations in the use of resources by imple- which corresponds to an area at approximately menting an interaction network analysis. Our 1 440 m elevation and “La Tajada”, which is temporal and spatial gradient was founded in at 980 m. These two areas are separated by no a primary forest region in the foothills of the more than 10 km. Samples were collected on Western Pacific cordillera of Colombia; a bio- April, May, June, August and October 2005, diversity hot-spot region highly rich in orchid excepting May in Ñambí due to excessive rainy bees (Otero, Chacón, Silverstone-Sopkins, & weather conditions. Giray, 2008; Otero & Sandino, 2003; Parra-H, Ospina-Torres, & Ramírez, 2006; Roubik & Pollen sampling: During collecting peri- Hanson, 2004; Sandino, 2004). ods male euglossinae bees were sampled for three days of baiting with Cineole, Methyl MATERIALS AND METHODS Salicylate or Skatole (Otero & Sandino, 2003) the baits were placed on filter paper and bees Study site: This study was conducted in were captured with an entomological net (Ack- “Río Ñambí” natural reserve, located at the erman, 1983). We obtained pollen samples municipality of Barbacoas, “corregimiento” from male bees by using the glycerinated gela- Altaquer, Nariño state - Southwest Colombia tine method (Amaya, Gutierrez, Rojas Giraldo, (1º18’00” N - 78º05’00” W). The reserve cov- & Villegas, 1999), which is widely used in bat ers an area in the Pacific foothills that varies in and bird pollination studies. By rubbing the altitude from 900 to 1 900 m.a.s.l, characterized bee bodies with fuchsine-stained gelatine we 648 Rev. Biol. Trop. (Int. J. Trop. Biol. ISSN-0034-7744) Vol. 63 (3): 647-658, September 2015 obtained pollen loads that were then mounted The resulting values of these three catego- on micro-slides. Each slide held the pollen ries were summed to calculate the arithmetic load of a single male body. Pollen grains were index IA, which provided a numeric descrip- observed using a LEICA® DMLS microscope tion of the resource relative importance for the with a 1 000x magnification, then identified euglossine bee community. Depending on the with help of pollen catalogues (Colinvaux de IA resulting value, plant species were classified Oliveira & Moreno, 1999; Palacios Chávez, as follows: Minor: IA = 3-4, scarcely visited by Ludlow-Wiechers, & Villanueva, 1991; Roubik few species along all year. & Moreno, 1991) and the palynological collec- Important: IA = 5-7, plant species of vari- tion of the Bee research Laboratory LABUN at able importance