Phylogeny and host-plant evolution in Melittidae s.l. (Hymenoptera: Apoidea) Denis Michez, Sébastien Patiny, Pierre Rasmont, Kim Timmermann, Nicolas J. Vereecken To cite this version: Denis Michez, Sébastien Patiny, Pierre Rasmont, Kim Timmermann, Nicolas J. Vereecken. Phylogeny and host-plant evolution in Melittidae s.l. (Hymenoptera: Apoidea). Apidologie, Springer Verlag, 2008, 39 (1), pp.146-162. hal-00891930 HAL Id: hal-00891930 https://hal.archives-ouvertes.fr/hal-00891930 Submitted on 1 Jan 2008 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 39 (2008) 146–162 Available online at: c INRA/DIB-AGIB/ EDP Sciences, 2008 www.apidologie.org DOI: 10.1051/apido:2007048 Original article Phylogeny and host-plant evolution in Melittidae s.l. (Hymenoptera: Apoidea)* Denis Michez1, Sébastien Patiny 2, Pierre Rasmont1,KimTimmermann3, Nicolas J. Vereecken4 1 Université de Mons-Hainaut, Laboratoire de Zoologie, Pentagone, 6 avenue du Champs de Mars, 7000 Mons, Belgium 2 Faculté universitaire des Sciences agronomiques de Gembloux, Unité d’Entomologie fonctionnelle et évolutive, 2 passage des Déportés, 5030 Gembloux, Belgium 3 Institute of Landscape Ecology, University of Münster, 26 Robert Koch-Strasse, 48149 Münster, Germany 4 Behavioural and Evolutionary Ecology, Free University of Brussels CP 160/12, 50 avenue F.D. Roosevelt, 1050 Brussels, Belgium Received 13 June 2007 – Revised 21 August 2007 – Accepted 25 September 2007 Abstract – Bees and the angiosperms they pollinate have developed intimate and often complex interactions over the past 100 million years. As in other insect-plant interactions, host-plant specificity is variable among taxa. While many solitary bee species display an obvious preference for a narrow spectrum of host-plants (oligolecty), others regularly visit a diversified array of pollen hosts (polylecty). Few studies have examined the patterns of host-plant associations in bees using well-resolved phylogenies at the species level combined with accurate and quantitative data on host-plant preferences. In this study, we examined the evolution of bee-plant relationships in several genera of specialist (oligolectic) bees. We used the Melittidae s.l. as a model taxon by mapping the preferred pollen hosts onto species-level phylogenies to investigate the fre- quency and pattern of host-plant switching. Our results suggest that host-plant associations are maintained over time in many lineages, but that host switches to unrelated plant families are also common. We find some evidence that host-switches occur more frequently to morphologically similar, rather than closely-related, host-plants suggesting that floral morphology plays a key role in host-plant evolution in bees. bees / Melittidae s.l. / oligolecty / polylecty / phylogeny / evolution / host-plant 1. INTRODUCTION animal-plant mutualisms. Like many groups of phytophagous insects (Jaenike, 1990), bees Bees constitute a monophyletic group of show variation in host-plant use as well as more than 16000 described species shar- host-plant breadth. Whereas many bee species ing morphological and behavioural adapta- exhibit floral specificity, visiting only a re- tions to forage on pollen and nectar from stricted number of suitable and available plant flowers (Linsley, 1958; Thorp, 1979, 2000; taxa throughout their range (i.e., monolecty or Eickwort and Ginsberg, 1980; Michener, oligolecty), others display a wider spectrum of 2000). Their exclusive reliance upon floral pollen hosts (i.e., mesolecty or polylecty). rewards throughout their life cycle makes With very few exceptions, morphologi- bee-flower interactions a textbook case of cal, behavioural and physiological constraints Corresponding author: D. Michez, are assumed to impact more significantly on [email protected] pollen than on nectar collection (Westerkamp, * Manuscript editor: Bryan Danforth 1996). Female bees typically have more nectar Article published by EDP Sciences and available at http://www.apidologie.org or http://dx.doi.org/10.1051/apido:2007048 Phylogeny and host-plant evolution in Melittidae s.l. (Hymenoptera: Apoidea) 147 than pollen host(s) (Robertson, 1925). Hence, such as floral oils (Vogel, 1974; Cane et al., characterizing a bee’s host breadth is best done 1983; Buchmann, 1987; Michez and Patiny, by recording the female’s pollen host-plant(s). 2005), flowers with hidden anthers (Müller, Roberston (1925) first proposed a classifi- 1995, 2006), flowers with large pollen grains cation of host breadth in bees. He described (Pasteels and Pasteels, 1979; Thorp, 1979), or three categories: 1. Monolecty (for bees for- nototribic flowers (Müller, 1996b). aging on only one plant species, i.e. extreme Only a few previous studies have exam- specialist bees), 2. Oligolecty (for bees forag- ined the pattern of host-plant evolution in spe- ing on one plant family, i.e. specialist bees), cialist bees using phylogenies at the species and 3. Polylecty (for bees foraging on more level (Müller, 1996a; Sipes and Wolf, 2001; than one plant family, i.e. generalist bees). Michez et al., 2004b; Sipes and Tepedino, Several studies since then have reported that 2005; Larkin et al., 2008). Such studies have this dichotomy between specialist and gener- generally indicated that host-plant associations alist bees reflects an oversimplification. For are maintained over multiple speciation events example, Rasmont (1988) proposed the term (suggesting that host-switching is not always mesolectic for the medium host breadth. In a associated with speciation), but that when host recent review, Cane and Sipes (2006) proposed switches occur, they occur to distantly related new definitions reflecting better the reality of host-plant families. a continuum in bee host breadth, from extreme In this study, we examined host-plant specialisation (monolecty) on one hand to ex- evolution in several genera of Melittidae s.l. treme generalisation (broad polylecty)onthe (families Dasypodaidae, Meganomiidae and other. These authors defined four intermediate Melittidae s.s.). We used parsimony to map the states: narrow oligolecty, oligolecty, mesolecty preferred pollen hosts onto species-level phy- and polylecty. logenies for five genera, all of which include Host specialisation has evolved multiple a large proportion of oligolectic species. Our times independently in bees (Wcislo and Cane, mapping of host-plant use allowed us to ex- 1996). Oligolecty is frequent in solitary bees amine (i) if host-plant shifts are frequent in with short life cycles in which bee emer- these specialist bee clades, (ii) the frequency gence and host-plant flowering are tightly cou- of host-plant shifts to distantly related hosts, pled (Hurd, 1957; Danforth, 1999; Minckley (iii) if host-plant switches involve the evolu- et al., 2000). Oligolecty is rare in eusocial tion of unique morphological adaptations, and bees. However, specialist bumblebees (Bom- (iv) if host-plant specialisation can be regarded bus consobrinus and B. gerstaeckeri; Ponchau as ancestral or derived within each of these et al., 2006) are known to forage exclu- genera. sively on pollen of Aconitum sp. Specialist We chose the Melittidae s.l. for several bees are particularly common in some lin- reasons. First, melittid bees are mainly dis- eages, such as Andrenidae, non-social Apinae, tributed in the Old World and they show low Lithurgini, Melittidae s.l., Paracolletini and species richness. The comprehensive study of Rophitinae (Linsley, 1958; Wcislo and Cane, specimens in museum collections and insti- 1996; Michener, 2000; Patiny et al., 2007; tutions across Europe is relatively easy. Sec- Larkin et al., 2008). ond, melittid bees form a specialist group In most cases, specialist bee species do not with a key position in the phylogeny of show morphological adaptations to their par- bees (Michener, 2000; Engel, 2001, Danforth ticular host-plants. Accessible rewards, such et al., 2006a,b). Third, supra-generic revisions as the pollen of Asteraceae, do not require are available and most of genera are well- special morphological features and there are delimited (Michener, 1981, 2000). many oligolectic bees that specialize on Aster- From the morphological point of view, aceae. However, some bee species show highly the traditional family Melittidae is some- modified morphological structures for gather- times considered as paraphyletic (Rozen and ing pollen from particular host-plants (Thorp, McGinley, 1974; Michener, 1981, Alexander 1979, 2000) or particular floral resources, and Michener, 1995; Michener, 2000). Using 148 D. Michez et al. Figure 1. Map of collecting localities for the 24 515 specimens of Melittidae included in the study. phylogenetic analyses based on a large mor- Michez and Kuhlmann (2007) for Capicola; phological data set, Alexander and Michener Michez et al. (2004b) for Dasypoda; Stage (1966) (1995) divided the traditional Melittidae into and Michener (1981) for Hesperapis; Michez and three families: Dasypodaidae, Meganomiidae Patiny (2005) for Macropis; Michez and Eardley and Melittidae s.str.. Danforth