Honey bee-collected pollen in agro-ecosystems reveals diet diversity, diet quality, and pesticide exposure.

European honey bees Apis mellifera are important commercial pollinators that have suffered greater than normal overwintering losses since 2007 in North America and Europe. Contributing factors likely include a combination of parasites, pesticides, and poor nutrition. We examined diet diversity, diet nutritional quality, and pesticides in honey bee-collected pollen from commercial colonies in the Canadian Maritime Provinces in spring and summer 2011. We sampled pollen collected by honey bees at colonies in four site types: apple orchards, blueberry fields, cranberry bogs, and fallow fields. Proportion of honey bee-collected pollen from crop versus noncrop flowers was high in apple, very low in blueberry, and low in cranberry sites. Pollen nutritional value tended to be relatively good from apple and cranberry sites and poor from blueberry and fallow sites. Floral surveys ranked, from highest to lowest in diversity, fallow, cranberry, apple, and blueberry sites. Pesticide diversity in honey bee-collected pollen was high from apple and blueberry sites and low from cranberry and fallow sites. Four different neonicotinoid pesticides were detected, but neither these nor any other pesticides were at or above LD50 levels. Pollen hazard quotients were highest in apple and blueberry sites and lowest in fallow sites. Pollen hazard quotients were also negatively correlated with the number of flower taxa detected in surveys. Results reveal differences among site types in diet diversity, diet quality, and pesticide exposure that are informative for improving honey bee and land agro-ecosystem management.

Phylogenetic analysis of Hepatozoon species (Apicomplexa: Adeleorina) infecting frogs of Nova Scotia, Canada, determined by ITS-1 sequences.

Species of Hepatozoon are apicomplexan parasites infecting tetrapod vertebrates and hematophagous arthropods. Two species, Hepatozoon catesbianae and Hepatozoon clamatae, have been described inhabiting the erythrocytes of bullfrogs and green frogs. A number of characteristics typically used to distinguish between members of this genus are shared between these 2 species, prompting speculation as to whether or not these organisms are in fact distinct species. To test the species distinction, bullfrogs and green frogs were captured at various sites across Nova Scotia, blood samples were collected, and DNA was extracted from samples containing parasites. The internal transcribed spacer 1 (ITS-1) from geographically diverse samples of both species was amplified by PCR, sequenced, and analyzed. ITS-1 sequences from the 2 species revealed single-nucleotide polymorphisms at 6 sites. Phylogenetic analysis of these molecular data and cytopathological features place isolates of each species in separate monophyletic groups. Comparison of the ITS-1 sequences between isolates from Nova Scotia and Ontario revealed that ITS-1 sequences of H. catesbianae from a previous study were mischaracterized as being those of H. clamatae. Phylogenetic data based on molecular variation and cytopathological features from this study provide the strongest evidence to date supporting the distinction between these 2 species.

Ancient allopolyploid speciation in Geinae (Rosaceae): evidence from nuclear granule-bound starch synthase (GBSSI) gene sequences.

A nuclear low-copy gene phylogeny provides strong evidence for the hybrid origin of seven polyploid species in Geinae (Rosaceae). In a gene tree, alleles at homologous loci in an allopolyploid species are expected to be sisters to orthologues in the ancestral taxa rather than to each other. Alleles at a duplicated locus in an autopolyploid, however, are expected to be more closely related to each other than they are to any orthologous copies in closely related species. We cloned and sequenced about 1.9 kilobases from the 5' end of the GBSSI-1 gene from two diploid, one tetraploid, and six hexaploid species. Each of the three loci in the hexaploid species forms a separate group, two of which are more closely related to copies in other species than they are to each other. This finding indicates that the hexaploid lineage evolved through two consecutive allopolyploidization events. Based on the GBSSI-1 gene tree, we hypothesized that there was an initial hybridization between a diploid species from the ancestral lineage of Coluria and Waldsteinia and an unknown diploid species to form the tetraploid Geum heterocarpum lineage. Backcrossing of G. heterocarpum with a representative of the unknown diploid lineage then resulted in a hexaploid lineage that has radiated considerably since its origin, comprising at least 40 extant species with various morphologies. A penalized likelihood analysis indicated that Geinae may be about 17 million years old, implying that the hypothesized allopolyploid speciation events are relatively ancient. Six of the 22 cloned Geinae GBSSI-1 copies in this study, which all are duplicate copies in polyploid taxa, may have become pseudogenes. We compared the GBSSI-1 phylogeny with one from chloroplast data and explored implications for the evolution of some fruit characters.

The origin of the apple subfamily (Maloideae; Rosaceae) is clarified by DNA sequence data from duplicated GBSSI genes.

For 70 yr the leading hypothesis for the origin of the Maloideae has involved wide hybridization between ancestors of two other subfamilies. The basis of this hypothesis is that Maloideae have a base chromosome number of 17, whereas other Rosaceae are mostly x = 7, 8, or 9. To investigate this hypothesis we cloned and sequenced approximately 1.8 kilobases from the 5' portion of granule-bound starch synthase (GBSSI, or waxy) genes for 89 clones from 32 Rosaceae genera. Previous studies demonstrate the presence of two copies in all Rosaceae (GBSSI-1 and GBSSI-2) and four in Maloideae (GBSSI-1A, GBSSI-1B, GBSSI-2A, and GBSSI-2B). Parsimony and maximum likelihood analyses nest Gillenia, a genus of the southeastern United States with a base chromosome number of 9, within either Maloideae GBSSI-1 or GBSSI-2. Monophyly of Maloideae plus Gillenia is well supported by bootstrap values, loss of the sixth intron in all GBSSI-1 sequences, intron alignability between genera, and numerous nonmolecular characters. Our results falsify the wide-hybridization hypothesis and are consistent with a polyploid origin involving only members of a lineage that contained the ancestors of Gillenia. Under this hypothesis, the subfamily originated in North America, and the high Maloideae chromosome number arose via aneuploidy from x = 18.