Phylogenetic relationships and host-plant evolution within the basal clade of Halictidae (Hymenoptera, Apoidea)

peer reviewedBees are among the most important pollinators of angiosperm plants. Many bee species show narrow host-plant preferences, reflected both in behavioral and morphological adaptations to particular attributes of host-plant pollen or floral morphology. Whether bee host-plant associations reflect co-cladogenesis of bees and their host plants or host-switches to unrelated host plants is not clear. Rophitinae is a basal subfamily of Halictidae in which most species show narrow host-plant preferences (oligolecty). We reconstructed the phylogenetic relationships among the rophitine genera using a combination of adult morphology (24 characters) and DNA sequence data (EF-1a, LW rhodopsin, wingless; 2700 bp total). The data set was analyzed by parsimony, maximum likelihood and Bayesian methods. All methods yielded highly congruent results. Using the phylogeny, we investigated the pattern of host-plant association as well as the historical biogeography of Rophitinae. Our biogeographical analysis suggests a number of dispersal / vicariance events: (1) a basal split between North America and South America (most likely a dispersal from South America to North America), and (2) at least two subsequent interchanges between North America and Eurasia (presumably via the northern hemisphere land bridges). Our analysis of host-plant associations indicates that Rophitinae specialized on a closely related group of angiosperm orders in the Euasterid I clade (mainly Gentianales, Lamiales and Solanales). However, there is little evidence of cocladogenesis between bees and plants and strong evidence of host switches to unrelated host plants. Based on our phylogenetic results we describe two new tribes of Rophitinae: Conanthalictini new tribe (including the genus Conanthalictus) and Xeralictini new tribe (including Xeralictus and Protodufourea)

Long-legged bees make adaptive leaps: linking adaptation to coevolution in a plant-pollinator network

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Playing with extremes: Origins and evolution of exaggerated female forelegs in South African Rediviva bees

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A solitary ground‐nesting wasp truncates its parental investment in response to detection of parasites

1. Parental investment by solitary nest-building wasps and bees is predicted to be plastic, responding to variation in the sex of the offspring, the availability of food used as provisions ('resource limitation'), the female's inventory of mature oocytes ('egg limitation'), and risk imposed by nest parasites. 2. I observed nest provisioning by Ammophila dysmica, a solitary, ground-nesting wasp that provisions its nest with one or two caterpillar prey to evaluate the hypotheses that provisioning is shaped by caterpillar size, offspring sex, the hunting time required to capture prey, a female's egg load, and penetration of nests by the parasites Argochrysis armilla and Hilarella hilarella. 3. Ammophila dysmica were more likely to add a second provision to the nest when the first prey item was relatively small and when provisioning daughters. 4. Neither the hunting time required to capture the first caterpillar prey nor the female's inventory of oocytes predicted a female's likelihood of adding a second caterpillar to a nest. Variation in oocyte inventory across females was minimal; all females examined had a mature or nearly mature oocyte remaining in the ovaries immediately after laying an egg. 5. Ammophila dysmica were much less likely to add a second caterpillar to nests that were penetrated by parasites during the first provisioning. 6. Although many nest parasites have evolved adaptations to avoid detection by their hosts, oviposition by A. armilla often appears to reveal its presence, eliciting an abrupt truncation of investment by the host in that nest.All needed metadata are included with the data files (see metadata tabs). Funding provided by: National Science FoundationCrossref Funder Registry ID: http://dx.doi.org/10.13039/100000001Award Number: Funding provided by: University of California BerkeleyCrossref Funder Registry ID: http://dx.doi.org/10.13039/100006978Award Number: Funding provided by: Sigma XiCrossref Funder Registry ID: http://dx.doi.org/10.13039/100011084Award Number: Funding provided by: University of Hawai'iCrossref Funder Registry ID: http://dx.doi.org/10.13039/100008782Award Number:All data were collected by direct observations in the field

The impact of molecular data on our understanding of bee phylogeny and evolution

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Bimodal pollination system in rare endemic Oncocyclus irises (Iridaceae) of Lebanon

Pollination systems based on indirect rewards, such as heat and shelter, have seldom been studied. Plant-pollinator interactions were characterized in Iris cedretii Dinsmore ex Chaudhary and Iris sofarana subsp. kasruwana Dinsmore ex Chaudhary, rare endemic Lebanese Oncocyclus irises exhibiting potential adaptation to shelter pollination. Despite a diversity of floral visitors (47 species), only two groups of Anthophoridae male bees (Xylocopa spp. and Eucera spp.) could be considered as efficient pollinators on the basis of frequency of visits, visiting behaviour, and pollen load. Lebanese Oncocyclus irises showed a bimodal pollination system with (1) diurnal visits at low rates but with potentially large pollen transfers by Xylocopa bees, exhibiting a foraging-like behaviour, principally during warm periods of the day and (2) sheltering, especially Eucera male bees, during night and day when the weather is changeable. Refuge occurrence in flowers was more important during the night (27%) than during the day (12%) and, for daytime, during cloudy or windy than sunny conditions. It also varied depending on the exposure of floral tunnels. Visitation rates of both day-visiting Xylocopa and night-sheltering Eucera were negatively associated with an increase of the number of flowers per clump. No experimental evidence was found showing that the principal advantage for male bees to shelter in Iris flowers was to fly earlier in the morning

Phylogenetics of the allodapine bee genus Braunsapis: historical biogeography and long-range dispersal over water

Aim. A previous study of the allodapine bee genus Braunsapis suggested an African origin, with dispersal events into Madagascar and Asia, and from Asia into Australia. We re-examine the phylogeny of this genus, using an expanded set of taxa from Madagascar and Malawi and additional sequence data, in order to determine the number of dispersals and the timeframe over which they occurred. Location. Africa, Madagascar, Malawi, Asia and Australia. Methods. One nuclear (EF-1a F2) and two mitochondrial (CO1 and Cyt b) gene regions were sequenced for 36 allodapine bee species (including members of the genera Braunsapis, Nasutapis, Allodape, Allodapula, and Macrogalea) and one ceratinine species (Ceratina japonica). We used Bayesian analyses to examine phylogenetic structure and a penalized likelihood approach to estimate approximate ages for key divergences in our phylogeny. Results. Our analyses indicate a tropical African origin for Braunsapis in the early Miocene followed by very early dispersal into Asia and then a subsequent dispersal, following Asian diversification, into Australia during the late Miocene. There have also been two dispersals of Braunsapis from Africa to Madagascar and this result, when combined with phylogenetic and biogeographical data for other allodapines, suggests that these bees have the ability to cross moderately large ocean expanses. These dispersals may have been aided by the West Wind Drift, but rafting across the Mozambique Channel is also possible, and could be aided by the existence of developmental stages that require minimal or no feeding and by tolerance to sea water and spume. Accumulating evidence suggests that many biogeographical patterns in the southern hemisphere may be better explained by dispersal than by Gondwanan vicariance hypotheses. Our results add to this growing body of data and raise the possibility that some puzzling trans-Indian Ocean distributions may also be explained by historical dispersal events across oceanic barriers that now seem insuperable