Long‐distance dispersal of non‐native pine bark beetles from host resources

1. Dispersal and host detection are behaviours promoting the spread of invading populations in a landscape matrix. In fragmented landscapes, the spatial arrangement of habitat structure affects the dispersal success of organisms. 2. The aim of the present study was to determine the long distance dispersal capabilities of two non‐native pine bark beetles (Hylurgus ligniperda and Hylastes ater) in a modified and fragmented landscape with non‐native pine trees. The role of pine density in relation to the abundance of dispersing beetles was also investigated. 3. This study took place in the Southern Alps, New Zealand. A network of insect panel traps was installed in remote valleys at known distances from pine resources (plantations or windbreaks). Beetle abundance was compared with spatially weighted estimates of nearby pine plantations and pine windbreaks. 4. Both beetles were found ≥25 km from the nearest host patch, indicating strong dispersal and host detection capabilities. Small pine patches appear to serve as stepping stones, promoting spread through the landscape. Hylurgus ligniperda (F.) abundance had a strong inverse association with pine plantations and windbreaks, whereas H. ater abundance was not correlated with distance to pine plantations but positively correlated with distance to pine windbreaks, probably reflecting differences in biology and niche preferences. Host availability and dispersed beetle abundance are the proposed limiting factors impeding the spread of these beetles. 5. These mechanistic insights into the spread and persistence of H. ater and H. ligniperda in a fragmented landscape provide ecologists and land managers with a better understanding of factors leading to successful invasion events, particularly in relation to the importance of long‐distance dispersal ability and the distribution and size of host patches.     

How do elevated CO2 and O3 affect the interception and utilization of radiation by a soybean canopy?

Net productivity of vegetation is determined by the product of the efficiencies with which it intercepts light (?_i) and converts that intercepted energy into biomass (?_c). Elevated carbon dioxide (CO₂) increases photosynthesis and leaf area index (LAI) of soybeans and thus may increase ?_i and ?_c; elevated O₃ may have the opposite effect. Knowing if elevated CO₂ and O₃ differentially affect physiological more than structural components of the ecosystem may reveal how these elements of global change will ultimately alter productivity. The effects of elevated CO₂ and O₃ on an intact soybean ecosystem were examined with Soybean Free Air Concentration Enrichment (SoyFACE) technology where large field plots (20‐m diameter) were exposed to elevated CO₂ (～550 μmol mol^?1) and elevated O₃ (1.2 × ambient) in a factorial design. Aboveground biomass, LAI and light interception were measured during the growing seasons of 2002, 2003 and 2004 to calculate ?_i and ?_c. A 15% increase in yield (averaged over 3 years) under elevated CO₂ was caused primarily by a 12% stimulation in ?_c , as ?_i increased by only 3%. Though accelerated canopy senescence under elevated O₃ caused a 3% decrease in ?_i, the primary effect of O₃ on biomass was through an 11% reduction in ?_c. When CO₂ and O₃ were elevated in combination, CO₂ partially reduced the negative effects of elevated O₃. Knowing that changes in productivity in elevated CO₂ and O₃ were influenced strongly by the efficiency of conversion of light energy into energy in plant biomass will aid in optimizing soybean yields in the future. Future modeling efforts that rely on ?_c for calculating regional and global plant productivity will need to accommodate the effects of global change on this important ecosystem attribute.     

Phylogeny and classification of whirligig beetles (Coleoptera: Gyrinidae): relaxed‐clock model outperforms parsimony and time‐free Bayesian analyses

Phylogenetic relationships among members of the family Gyrinidae (Coleoptera: Adephaga) were inferred from analysis of 42 morphological characters and DNA sequence data from the genes 12S rRNA, cytochrome c oxidase I and II, elongation factor 1 alpha (2 different copies) and histone III. Eighty‐nine species of Gyrinidae were included representing all known subfamilies, tribes and genera. Outgroups include species from Noteridae, Paelobiidae and Dytiscidae. Analyses include parsimony analysis, and partitioned time‐free and relaxed‐clock Bayesian analyses of the combined data using reversible‐jump MCMC to simultaneously integrate over all possible 4 × 4 nucleotide substitution models. Analyses resulted in conflicting topologies between the combined parsimony and Bayesian analyses on the one hand, and the relaxed‐clock analysis on the other. The marginal likelihoods of competing models were calculated with stepping‐stone sampling and used in a Bayes factor test, which, along with arguments from morphology, supported the topology generated by the relaxed‐clock analysis. This phylogenetic hypothesis is adopted to revise the higher classification of Gyrinidae. Major taxonomic conclusions include: (i) monophyletic Gyrinidae, (ii) the Nearctic Spanglerogyrinae Folkerts (with one species, Spanglerogyrus albiventris Folkerts) sister to all other Gyrinidae, (iii) the Madagascar endemic Heterogyrinae Brinck stat. n. (with one species, Heterogyrus milloti Legros) sister to all Gyrinidae except Spanglerogyrinae, (iv) monophyletic Gyrininae Latreille including three monophyletic tribes with the following relationship: Orectochilini Régimbart + (Gyrinini Latreille + Enhydrini Régimbart), (v) monophyletic Orectochilini comprising four monophyletic genera with the following relationships: (Gyretes Brullé + Patrus Aubé stat. n. ) + (Orectogyrus Régimbart + Orectochilus Dejean), (vi) monophyletic Gyrinini comprising three genera with the following relationships: Gyrinus Geoffroy + (Metagyrinus Brinck + Aulonogyrus Motschulsky), each monophyletic except Metagyrinus with only one included species and not tested for monophyly, and (vii) monophyletic Enhydrini comprising five genera with the following relationships: (Porrorhynchus Laporte + Dineutus MacLeay) + (Enhydrus Laporte + (Andogyrus Ochs + Macrogyrus Régimbart)), each monophyletic except Porrorhynchus, Enhydrus and Andogyrus each with one included species and untested for monophyly. Each subfamily, tribe and genus is diagnosed and discussed. The female reproductive tract of each group is presented, illustrated and discussed with respect to the phylogenetic conclusions.     

INDUCTION OF OVARIAN DEVELOPMENT IN AUTOGENOUS AEDES ATROPALPUS BY JUVENILE HORMONE AND 20-HYDROXYECDYSONE

Aedes atropalpus is an autogenous mosquito characterized by a first gonadotropic cycle which results in approximately 200 mature oocytes without a bloodmeal. Ovarian development is completely inhibited if these animals are decapitated or ligated between the thorax and abdomen shortly after adult emergence. Injection of 4.8 ng of 20-hydro- xyecdysone into decapitated females 12 h after eclosion restores ovarian development in all females so treated. However, the same amount of 20-hydroxyecdysone injected into isolated abdomens obtained shortly after adult emergence had no discernible effect on vitellogenesis. In contrast, all abdomens which received 0.5 ng of topically applied JH I followed by the injection of 4.8 ng 20-hydroxyecdysone produced mature oocytes. Isolated abdomens were also capable of oocyte maturation when treated with excess amounts of JH alone; JH I was the most effective followed by JH II and then JH III.

Polyacrylamide gel electrophoretic analysis of vitellin extracted from the ovaries of hormonally-treated animals did not reveal any qualitative differences compared to intact normal controls. However, less yolk protein was present in the former. This was verified by counting the number and measuring the size of ovarian follicles in individual females.     

An Ethnoarchaeological Study of Mobility, Architectural Investment, and Food Sharing among Madagascar's Mikea

Ethnoarchaeology is a field of study that aims to provide the information needed to draw reliable behavioral inferences from archaeological data. In this study, data from four settlement types (permanent villages, forest hamlets, seasonal hamlets, and foraging camps) of a forager–farmer population in southwestern Madagascar are examined from an archaeological perspective. Doing so shows that house size, house post diameter variability, outdoor workspace, trash disposal, and feature diversity jointly sort out settlements of different lengths of occupation. However, the relationship between mobility and material culture is not simply a product of the length of stay; it is also affected by differences in the social environments of settlements of different occupational lengths. Using the behavioral ecology of food sharing, we show that certain architectural changes that ensure privacy are expected to occur as settlements become larger and more permanent. These observations from Madagascar should be applicable to other areas.     

Discordant patterns of evolutionary differentiation in two Neotropical treefrogs

Comparative studies of codistributed taxa test the degree to which historical processes have shaped contemporary population structure. Discordant patterns of lineage divergence among taxa indicate that species differ in their response to common historical processes. The complex geologic landscape of the Isthmus of Central America provides an ideal setting to test the effects of vicariance and other biogeographic factors on population history. We compared divergence patterns between two codistributed Neotropical frogs ( Dendropsophus ebraccatus and Agalychnis callidryas ) that exhibit colour pattern polymorphisms among populations, and found significant differences between them in phenotypic and genetic divergence among populations. Colour pattern in D. ebraccatus did not vary with genetic or geographic distance, while colour pattern co-varied with patterns of gene flow in A. callidryas . In addition, we detected significant species differences in the phylogenetic history of populations, gene flow among them, and the extent to which historical diversification and recent gene flow have been restricted by five biogeographic barriers in Costa Rica and Panama. We inferred that alternate microevolutionary processes explain the unique patterns of diversification in each taxon. Our study underscores how differences in selective regimes and species-typical ecological and life-history traits maintain spatial patterns of diversification.     

Trumpeter Swan Abundance and Growth Rates in Yellowstone National Park

ABSTRACT Decreasing abundance of resident, nonmigratory trumpeter swans (Cygnus buccinator) in Yellowstone National Park (YNP), USA, raised concern that this population, which helped facilitate the restoration of the species across North America, may disappear. We quantified trends in abundance of resident and migratory trumpeter swans in YNP from 1967 to 2007 and investigated the potential mechanisms for declining population trends, including cessation of the supplemental feeding program and relocation programs outside of YNP, density dependence, and annual variations in environmental conditions. Estimated abundance of resident trumpeter swans in YNP ranged from 59 individuals in 1968 to 10 individuals in 2007. Using log-linear modeling, the best approximating model chosen from an a priori set of competing models estimated the annual growth rate (r) of resident swans from 1967 to 2007 was −0.036 (95% CI =−0.042 to −0.030, Akaike wt [w_i] = 0.44). A competing model provided evidence that decreases in abundance became more dramatic after supplemental feeding of grain outside of YNP was terminated in winter 1992–1993 (r̂_1967–1992 = −0.027, 95% CI = −0.039 to −0.015; r̂_1993–2007 = −0.053, 95% CI = −0.029 to −0.080; w_i = 0.42). There was little evidence of density-dependent effects on the resident population growth rates (βYNP_pop = 0.006, 95% CI = −0.017 to 0.007), but rates were lower following severe winters, wetter springs, and warmer summers. Our results indicate that the YNP population of trumpeter swans is decreasing and may act as a sink to surrounding populations. Thus, population levels of YNP trumpeter swans may depend on management outside the Park and we recommend the National Park Service collaborate with surrounding agencies in managing trumpeter swans throughout the Tri-state region where more productive habitats may exist.