Phylogeny and taxonomy of the Prenolepis genus‐group of ants (Hymenoptera: Formicidae)

Abstract. We investigated the phylogeny and taxonomy of the Prenolepis genus‐group, a clade of ants we define within the subfamily Formicinae comprising the genera Euprenolepis, Nylanderia, gen. rev. , Paraparatrechina, gen. rev. & stat. nov. , Paratrechina, Prenolepis and Pseudolasius. We inferred a phylogeny of the Prenolepis genus‐group using DNA sequence data from five genes (CAD, EF1αF1, EF1αF2, wingless and COI) sampled from 50 taxa. Based on the results of this phylogeny the taxonomy of the Prenolepis genus‐group was re‐examined. Paratrechina (broad sense) species segregated into three distinct, robust clades. Paratrechina longicornis represents a distinct lineage, a result consistent with morphological evidence; because this is the type species for the genus, Paratrechina is redefined as a monotypic genus. Two formerly synonymized subgenera, Nylanderia and Paraparatrechina, are raised to generic status in order to provide names for the other two clades. The majority of taxa formerly placed in Paratrechina, 133 species and subspecies, are transferred to Nylanderia, and 28 species and subspecies are transferred to Paraparatrechina. In addition, two species are transferred from Pseudolasius to Paraparatrechina and one species of Pseudolasius is transferred to Nylanderia. A morphological diagnosis for the worker caste of all six genera is provided, with a discussion of the morphological characters used to define each genus. Two genera, Prenolepis and Pseudolasius, were not recovered as monophyletic by the molecular data, and the implications of this result are discussed. A worker‐based key to the genera of the Prenolepis genus‐group is provided.     

The effects of temperature, body mass and feeding on metabolic rate in the tsetse fly Glossina morsitans centralis

Abstract.  Metabolic rate variation with temperature, body mass, gender and feeding status is documented for Glossina morsitans centralis . Metabolic rate [mean ± SE; VCO₂= 19.78 ± 3.11 μL CO₂ h⁻¹ in males (mean mass = 22.72 ± 1.41 mg) and 27.34 ± 3.86 μL CO₂ h⁻¹ in females (mean mass = 29.28 ± 1.96 mg) at 24 °C in fasted individuals] is strongly influenced by temperature, body mass and feeding status, but not by gender once the effects of body mass have been accounted for. A significant interaction between gender and feeding status is seen, similar to patterns of metabolic rate variation documented in Glossina morsitans morsitans . Synthesis of metabolic rate-temperature relationships in G. m. centralis , G. m. morsitans and Glossina pallidipes indicate that biting frequency as well as mortality risks associated with foraging will probably increase with temperature as a consequence of increasing metabolic demands, although there is little evidence for variation among species at present. Furthermore, metabolic rate–body mass relationships appear to be similarly invariant among these species. These data provide important physiological information for bottom-up modelling of tsetse fly population dynamics.     

P-values for group sequential testing

Group sequential testing procedures are widely employed in long-termclinical trials. We discuss several methods for computing theP-value following a group sequential trial based on differentoutcome-space orderings. We use a criterion defined in thispaper to compare these methods and point out interesting differences.     

Are behavioural responses to predation cues linked across life cycle stages?

1. Prey organisms can perceive cues to predation hazard and adopt low‐risk behaviours to increase survival. Animals with complex life cycles, such as insects, can exhibit such anti‐predatory behaviours in multiple life stages. 2. Cues to predation risk may induce ovipositing females to choose habitats with low predation risk. Cues to predation risk may also induce larvae to adopt facultative behaviours that reduce risk of predation. 3. One hypothesis postulates that anti‐predation behaviours across adult and larval stages may be negatively associated because selection for effective anti‐predator behaviour in one stage leads to reduced selection for avoidance of predators in other stages. An alternative hypothesis suggests that selection by predation favours multi‐component defences, with both avoidance of oviposition and facultative adoption of low‐risk behaviours by larvae. 4. Laboratory and field experiments were used to determine whether defensive responses of adult and larval mosquitoes are positively or negatively associated. The study tested effects of waterborne cues from predatory Toxorhynchites theobaldi on oviposition choices and larval behaviours of three of its common prey: Culex mollis, Limatus durhamii and Aedes albopictus. 5. Culex mollis shows strong anti‐predator responses in both life stages, consistent with the hypothesis of a multi‐component behavioural defence. The other two species showed no detectable responses to waterborne predator cues in either adult or larval stages. Larvae of these unresponsive species were significantly more vulnerable to this predator than was C. mollis. 6. For these mosquitoes, species appear either to have been selected for multi‐component defences against predation or to act in ways that could be called predator‐naïve.     

Isolation and characterization of 13 polymorphic microsatellite loci for the Florida pompano,Trachinotus carolinus

Here we describe 13 polymorphic, dinucleotide microsatellite loci for Trachinotus carolinus (Florida pompano), isolated by using PIMA, a polymerase chain reaction‐based technique. The number of alleles at each locus ranged from 3 to 29 (mean = 11.4) in 45 specimens collected from bay and nearshore waters around St Petersburg, Florida. Levels of expected and observed heterozygosities ranged from 0.15 to 0.94 (mean = 0.69) and from 0.16 to 0.98 (mean = 0.70), respectively. No significant departures from Hardy–Weinberg equilibrium expectations were observed. In exact tests for genotypic disequilibrium, there was no evidence of linkage for any pair of loci. The ability of these markers to cross‐amplify in two congeneric Trachinotus species —T. falcatus (permit) and T. goodei (palometa) — was also assessed. The loci were well‐resolved, highly polymorphic, and independently segregating in these taxa, also suggesting a general utility for intraspecific studies, species identification, and investigation of interspecific hybridization.     

Genetically and geographically isolated lineages of a tropical bat (Chiroptera: Molossidae) show demographic stability over the late Pleistocene

The newly described molossid bat, Chaerephon atsinanana Goodman et al., 2010, endemic to eastern Madagascar, shows notably high levels of phylogeographic and genetic structure compared with allopatric Chaerephon leucogaster Grandidier, 1869 from western Madagascar. Such highly significant structuring of haplotypes among altitudinally and latitudinally stratified population groups is contrary to the expected panmixia in strong flying bats. The null model of concordance in historical demographic patterns across these two Chaerephon species was not supported. Mismatch and Bayesian skyline analyses indicated ancient stable C. atsinanana populations of constant size during the last two major Pleistocene glacial periods, making retreat into and expansion from glacial refugia an unlikely explanation for such high levels of structure, in accordance with expectations for tropical bats. Analyses were consistent with post‐refugial population expansion in the less diverse and structured C. leucogaster during the end of the last Pleistocene glacial period. We hypothesise that the pronounced genetic structuring in C. atsinanana may result from female philopatry. Furthermore, differing demographic histories of the two species may have been shaped by differing climate or habitat preferences, consistent with evidence from MaxEnt ecological niche modelling, which shows differences in variables influencing the current predicted distributions. Fossil Quaternary pollen deposits further indicate greater stability in past climatic patterns in eastern versus western Madagascar. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 18–40.     

Geographical variation in cone volatile composition among populations of the African cycad Encephalartos villosus

Variation in traits across species distribution ranges is often indicative of diversifying evolution that can lead to speciation. Of particular interest is whether traits vary clinally or abruptly because the latter pattern can be indicative of incipient speciation. Understanding of intraspecific variation in chemical traits is still in its infancy because studies of population variation have tended to focus on morphology or neutral genetic markers. To address these issues, the composition of cone volatile odours was examined in ten populations of the South African cycad Encephalartos villosus across its range in the Eastern Cape and KwaZulu Natal using headspace sampling and analysis by gas chromatography‐mass spectrometry. Because volatiles play a key role in attracting pollinators to cones of Encephalartos cycads and may thus reflect local adaptation to pollinators, pollinator assemblages were also investigated in the ten populations of E. villosus. Volatile compounds from populations in the north of the distribution range were dominated by unsaturated hydrocarbons, whereas, in the southern populations, nitrogen‐containing compound and terpenoids were the major compounds. A shift between southern and northern populations appeared to occur at the Umtamvuna River, where populations had odour profiles with components of both the northern and southern populations. However, one population in the north (Vernon Crookes Nature Reserve) had a quantitatively similar odour profile to the populations in the extreme south of the range. These results reveal strong interpopulation variation in the cone scent of E. villosus, including variation in the relative emission of dominant compounds that may play key functional role in this pollination system. However, pollinator assemblages did not differ across the different populations, which suggest that these patterns were produced by co‐evolution or drift, rather than by pollinator shifts. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 514–527.     

Upwind Movement of Achenes of Centaurea eriophora L. on the Ground

The lightly compressed achenes of Centaurea eriophora L. beara pappus composed of stiff bristles at their apex and have anelaiosome appendage at their base. The pappus is ineffectivein keeping the achene wind-borne but does serve to regulatethe movement of the achene on the ground in response to wind.In wind the achene swivels like a weather vane with the baseof the achene pointing into the wind. In weak wind the pappusbristles prevent the achene from blowing away. In stronger windthe bristles move due to their flattened, flexible, hinge-likebases and act like ratchets against the substratum, thus enablingthe achene to move upwind. In either case achenes remain ingroups. Ants are attracted to the elaiosome and disperse theachenes. Wind-induced movement was explored by testing acheneson various substrata in a wind tunnel at free-stream speedsbetween 2 and 7 m s^-1. Wind dispersal; Centaurea eriophora ; seeds; achenes     

Characterization of SSRs from the American lobster,Homarus americanus

The American lobster (Homarus americanus), a commercially important benthic marine crustacean, is widely distributed along the continental shelf of the western North Atlantic. The population substructure of this species remains poorly understood despite its economic value. Informative markers are required to clarify relationships between local populations. To this end, we developed eight polymorphic short sequence repeats (SSR) for the American lobster, which were derived from expressed sequence tags. Additionally, we tested four SSRs previously identified for the Norway lobster (Nephrops norvegicus L.) for cross‐species utility; only one of these showed polymorphism.     

Analyses of the secretomes of Erwinia amylovora and selected hrp mutants reveal novel type III secreted proteins and an effect of HrpJ on extracellular harpin levels

Erwinia amylovora is a plant pathogenic enterobacterium that causes fire blight disease of apple, pear and other rosaceous plants. A type III (T3) secretion system, encoded by clustered, chromosomal hrp genes (hypersensitive response and pathogenicity), is essential for infection, but only a few proteins are known that are secreted through this pathway (the T3 'secretome'). We developed an efficient protocol for purification and concentration of extracellular proteins and used it to characterize the T3 secretome of E. amylovora Ea273 by comparing preparations from the wild-type strain with those from mutants defective in hrp secretion, regulation, or in genes encoding putative T3-secreted proteins. Proteins were resolved by gel electrophoresis and identified using mass spectrometry and a draft sequence of the E. amylovora genome. Twelve T3-secreted proteins were identified, including homologues of known effector and helper proteins, and HrpJ, a homologue of YopN of Yersinia pestis . Several previously uncharacterized T3-secreted proteins were designated as Eops for Erwinia outer proteins. Analysis of the secretome of a non-polar hrpJ mutant demonstrated that HrpJ is required for accumulation of wild-type levels of secreted harpins. HrpJ was found to be essential for pathogenesis, and to play a major role in elicitation of the hypersensitive reaction in tobacco.