ABSTRACT
Understanding animal foraging ecology requires large sample sizes spanning broad environmental and temporal gradients. For pollinators, this has been hampered by the laborious nature of morphologically identifying pollen. Identifying pollen from urban environments is particularly difficult due to the presence of diverse ornamental species associated with consumer horticulture. Metagenetic pollen analysis represents a potential solution to this issue. Building upon prior laboratory and bioinformatic methods, we applied quantitative multilocus metabarcoding to characterize the foraging ecology of honeybee colonies situated in urban, suburban, mixed suburban-agricultural and rural agricultural sites in central Ohio, USA. In cross-validating a subset of our metabarcoding results using microscopic palynology, we find strong concordance between the molecular and microscopic methods. Our results suggest that forage from the agricultural site exhibited decreased taxonomic diversity and temporal turnover relative to the urban and suburban sites, though the generalization of this observation will require replication across additional sites and cities. Our work demonstrates the power of honeybees as environmental samplers of floral community composition at large spatial scales, aiding in the distinction of taxa characteristically associated with urban or agricultural land use from those distributed ubiquitously across the sampled landscapes. Observed patterns of high forage diversity and compositional turnover in our more urban sites are likely reflective of the fine-grain heterogeneity and high beta diversity of urban floral landscapes at the scale of honeybee foraging. This provides guidance for future studies investigating how relationships between urbanization and measures of pollinator health are mediated by variation in floral resource dynamics across landscapes.
Subject(s)
Plants , Pollen , Animals , Bees/genetics , Cities , Ohio , Pollen/genetics , UrbanizationABSTRACT
Subterranean termites in the genus Heterotermes Froggatt (Rhinotermitidae: Heterotermitinae) are pantropical wood feeders capable of causing significant structural damage. The aim of this study was to investigate soldier morphological attributes in three Puerto Rican species of Heterotermes previously identified by sequencing of two mitochondrial genes and attributed to Heterotermes tenuis (Hagen), H. convexinotatus (Snyder) and H. cardini (Snyder). Soldiers (n = 156) were imaged and measured using the Auto-Montage image-stacking program. We demonstrated that Puerto Rican Heterotermes soldiers could not be identified to species level based upon seven morphometric indices or any combination thereof. Nor could differences in soldier head pilosity be used to discriminate species, in contrast to previous findings. However, previously described characters of the soldier tergal setae were reported to be useful in discriminating H. tenuis from both of its Puerto Rican congeners.
ABSTRACT
The goal of this study was to infer Heterotermes (Froggatt) (Dictyoptera: Rhinotermitidae) species diversity on the island of Puerto Rico from phylogenetic analyses of DNA sequence data from two mitochondrial genes, 16S rRNA and cytochrome oxidase II (COII). This termite genus is a structural pest known to be well adapted to arid environments in subtropical and tropical regions worldwide including Puerto Rico and many other Caribbean islands. Extensive sampling was accomplished across Puerto Rico, and phylogenetic analyses of individual gene sequences from these samples indicated robust datasets of congruent gene tree topologies showing three monophyletic groups: H. cardini (Snyder), H. convexinotatus (Snyder), and H. tenuis (Hagen). We found that H. cardini and H. convexinotatus were widespread in the arid coastal regions of Puerto Rico, whereas H. tenuis was uncommon and may represent a relatively new introduction. We found only H. convexinotatus on Culebra Island. We provide strong evidence that Puerto Rico may be linked to the Heterotermes in southern Florida, USA, since its GenBank 16S sequence was identical to that of seven Puerto Rican H. cardini sequences. Our study represents the first records of H. cardini from Puerto Rico and Grand Bahama.
ABSTRACT
The stink bug, Megacopta cribraria, has an obligate relationship with a bacterial endosymbiont which allows it to feed on legumes. The insect is a pest of soybeans in Asia and was first reported in the Western Hemisphere in October 2009 on kudzu vine, Pueraria montana, in North Georgia, USA. By October 2010 M. cribraria had been confirmed in 80 counties in Georgia actively feeding on kudzu vine and soybean plants. Since the symbiosis may support the bug's ecological expansions, a population genetic baseline for the symbiosis was developed from mitochondrial DNA (mtDNA) and nuclear DNA (nuDNA) gene sequence collected from each insect and its primary g- proteobacterium and secondary a -proteobacterium endosymbionts. A single mitochondrial DNA haplotype was found in all insects sampled in Georgia and South Carolina identified as GA1. The GAI haplotype appears to be rapidly dispersing across Georgia and into contiguous states. Primary and secondary endosymbiont gene sequences from M. cribraria in Georgia were the same as those found in recently collected Megacopta samples from Japan. The implications of these data are discussed.
