Floral Oil Collection by Male Tetrapedia Bees (Hymenoptera: Apidae: Tetrapediini) Simone Cappellari, Gabriel Melo, Antonio Aguiar, John Neff
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Floral oil collection by male Tetrapedia bees (Hymenoptera: Apidae: Tetrapediini) Simone Cappellari, Gabriel Melo, Antonio Aguiar, John Neff To cite this version: Simone Cappellari, Gabriel Melo, Antonio Aguiar, John Neff. Floral oil collection by male Tetrapedia bees (Hymenoptera: Apidae: Tetrapediini). Apidologie, Springer Verlag, 2011, 43 (1), pp.39-50. 10.1007/s13592-011-0072-2. hal-01003609 HAL Id: hal-01003609 https://hal.archives-ouvertes.fr/hal-01003609 Submitted on 1 Jan 2011 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Apidologie (2012) 43:39–50 Original article * INRA, DIB-AGIB and Springer Science+Business Media B.V., 2011 DOI: 10.1007/s13592-011-0072-2 Floral oil collection by male Tetrapedia bees (Hymenoptera: Apidae: Tetrapediini) 1 2 3 4 Simone C. CAPPELLARI , Gabriel A. R. MELO , Antonio J. C. AGUIAR , John L. NEFF 1Section of Integrative Biology, The University of Texas at Austin, One University Station A6700, Austin, TX 78712, USA 2Lab. Biol. Comparada Hymenoptera, Departamento de Zoologia, Universidade Federal do Paraná, Caixa Postal 19020, BR-81531-980, Curitiba, Paraná, Brazil 3Departamento de Zoologia, Universidade de Brasília, Campus Universitário Darcy Ribeiro, BR-70910-900, Brasília, Distrito Federal, Brazil 4Central Texas Melittological Institute, 7307 Running Rope, Austin, TX 78731, USA Received 14 February 2011 – Revised 24 April 2011 – Accepted 23 June 2011 Abstract – Several groups of solitary bees, known as oil-collecting bees, gather lipids from flowers that offer them as their main reward to pollinators. In the Neotropical region, oil-collecting bees belong to the tribes Centridini, Tapinotaspidini, and Tetrapediini (Apidae: Apinae). The floral oils collected by females of these groups are used as larval food or in nest construction. The interaction of these bees with oil flowers is characterized by the presence of specialized structures for oil collection on the legs that morphologically match the location and type of the oil-producing glands on flowers they visit. In addition, these bees have specialized arrays of setae (including the scopae) for oil transport. In a few genera, both sexes display such specialized structures, although floral oil collection has hitherto been regarded as an exclusively female task. Here, we report floral oil collection by males of Tetrapedia, a Neotropical genus of oil-collecting bees. We describe behavioral aspects of oil foraging by males, present data on morphological structures associated with the collection of this resource, and discuss potential hypotheses to explain the significance of floral oils in the mating system of Tetrapedia. Cerrado / mating / Neotropical / oil-collecting bees / oil flowers / solitary bees 1. INTRODUCTION either parental care or nest construction, tasks which are performed by females. Males usually Male and female bees often differ in their visit flowers to acquire resources for their own foraging apparatuses, floral preferences, and feeding, for mating, or more rarely, to obtain foraging behavior. These differences are typically resources used in mating (Eickwort and Ginsberg associated with the purposes for which each sex 1980). Since male bees usually forage only for forages for resources (Eickwort and Ginsberg nectar, for which only the mouthparts are used, 1980). Male bees normally do not contribute to they typically lack the numerous specialized structures possessed by females to collect and transport floral resources such as pollen, resin, or Corresponding author: S.C. Cappellari, fatty oils (Michener 2007). Specialized modifi- [email protected] cations of the body appendages are common in Manuscript editor: David Tarpy male bees, but their presence usually is associ- 40 S.C. Cappellari et al. ated with mating behaviors such as signaling or floral oils (Neff and Simpson 1981; Alves-dos- grasping potential mates (Anzenberger 1977; Santos et al. 2006, 2007). The oil-collecting Dressler 1982; Norden and Batra 1985; Wirtz structures of Tetrapedia appear to be adapted for et al. 1988; Wittmann and Blochtein 1995; harvesting oils from flowers with epithelial Michener 2007). elaiophores as found in the Malpighiaceae, and A notable exception to this pattern is found females have commonly been associated with among certain oil-collecting bees. The oil bees flowers of that plant family (Neff and Simpson are a polyphyletic assemblage of roughly 400 1981). Although females of several Tetrapedia species occurring on all continents except species are known to collect and use floral oils Antarctica (Michener 2007). Female oil bees for larval provisioning and nest construction, collect fatty oils from specialized glands (elaio- the presence of similar structures in the males phores) found on the flowers of more than was problematic, since males of this genus, like 1,600 plant species from 11 angiosperm families most male bees, leave their natal nest soon after (Renner and Schaefer 2010). These elaiophores emerging and spend their lives searching for vary widely in their form, size, and location mates. Detailed observations at nests have (Vogel 1974). Accordingly, different oil- established that the males do not provide any collecting bees have different types of structures form of parental care nor participate in nest to harvest and transport the oils of particular construction (Michener and Lange 1958;Roubik elaiophores types (Vogel 1974; Neff and Simpson 1992; Alves-dos-Santos et al. 2002; Camillo 1981; Roig-Alsina 1997). Normally, these struc- 2005); thus, it was not clear why they have tures are found only on the females but in two structures that might be used for collecting floral clades of Neotropical oil-collecting bees, Tetra- oils. Use of oil as an adult food source, or to play pediini and Tapinotaspidini (both Apidae: some role in mating behavior have been sug- Apinae), the fore legs of the males have gested as possible functions (Neff and Simpson structures virtually identical to those that their 1981), but no data to either confirm or reject femalesareknowntousetoharvestfloraloils these hypotheses have been previously available. (Neff and Simpson 1981; Roig-Alsina 1997). Our data consist of detailed behavioral observa- Since the discovery of the oil flower pollina- tions and a morphological study of the male oil- tion syndrome, scattered field observations collecting apparatus, including the description of have suggested that some males of these two an oil-storage structure found uniquely on males tribes may collect floral oils (Friese 1925; of Tetrapedia. We discuss the possible signifi- Vogel 1974; Cocucci 1991; Vogel and Machado cance of oil collecting for the mating biology of 1991; Singer and Cocucci 1999; Rasmussen this group based on our findings and the and Olesen 2000; Aguiar and Melo 2009). literature. However, the fragmentary nature of the data has left many unanswered questions about the function of floral oil collection by male bees. 2. MATERIAL AND METHODS Here, we provide direct evidence for active floral oil collection by males of four species of 2.1. Field sites Tetrapedia that repeatedly visited oil flowers of Malpighiaceae in the Brazilian Cerrado. Field observations were independently carried out Tetrapedia (Apidae: Apinae: Tetrapediini) is a by the first three authors at various sites within the Neotropical genus of approximately 28 species Brazilian Cerrado. Oil collection by male Tetrapedia of solitary, cavity-nesting bees (Silveira et al. was observed by G. A. R. Melo in Tibagi, Paraná 2002; Moure 2007). Unlike most other oil- (24°32′ S, 50°16′ W; 990 m ASL) on November 30, collecting bees, both males and females of this 2003; by A. J. C. Aguiar at the Reserva Particular do genus display a variety of morphological and Patrimônio Natural “Cachoeira do Campo,” Serra do behavioral features for effective collection of Salitre, Minas Gerais (19°16′ S, 46°56′ W, 1,099 m Floral oil foraging by male bees 41 ASL) at the beginning of the wet season during 2.4. Behavioral observations October 2005; and by S. C. Cappellari at the Reserva Ecológica do IBGE (RECOR; 15°56′ S, 47°52′ W; Detailed observations on oil-collecting behavior of 1,087 m ASL) in Brasília, Distrito Federal, during the males were carried for two species (T. diversipes and wet (October to April) and dry (May to September) T. aff. peckoltii) on flowers of Heteropterys tomentosa seasons 2007–2010. A. Juss., over several days during June 2009 at RECOR. We documented details of their behavior by 2.2. Floral records video recording using a Nikon Coolpix P80 camera, as well as focal observations. Films were later Males of four species of Tetrapedia were recorded analyzed frame by frame using a VLC media player collecting oils on flowers of seven Malpighiaceae and were used to produce drawings illustrating the species. Specimens were collected after observations movements performed by males. Males observed and killed with ethyl acetate for later study. Pinned collecting oils on flowers were easily distinguished specimens were preliminary identified by A. J. C. from females in the field based on their distinctive Aguiar and S. C. Cappellari. Species identity of all hind leg morphology, hair pattern, and size. collected specimens was later confirmed by G. A. R. Melo using the literature and by comparisons with type material from the Department of Zoology 3. RESULTS (Coleção Entomológica Padre J. S. Moure) of the Universidade Federal do Paraná (DZUP), Brazil and 3.1. Morphology of oil-collecting structures the Museum für Naturkunde (ZMB), Germany. Bee vouchers were deposited in the entomological collec- Most structures of the oil-collecting appara- tions of the Universidade de Brasília (UnB) and DZUP.