Dynamics of leaf water relations components in co‐occurring iso‐ and anisohydric conifer species

Because iso‐ and anisohydric species differ in stomatal regulation of the rate and magnitude of fluctuations in shoot water potential, they may be expected to show differences in the plasticity of their shoot water relations components, but explicit comparisons of this nature have rarely been made. We subjected excised shoots of co‐occurring anisohydric Juniperus monosperma and isohydric Pinus edulis to pressure‐volume analysis with and without prior artificial rehydration. In J. monosperma, the shoot water potential at turgor loss (Ψ_TLP) ranged from ?3.4 MPa in artificially rehydrated shoots to ?6.6 MPa in shoots with an initial Ψ of ?5.5 MPa, whereas in P. edulis mean Ψ_TLP remained at ～ ?3.0 MPa over a range of initial Ψ from ?0.1 to ?2.3 MPa. The shoot osmotic potential at full turgor and the bulk modulus of elasticity also declined sharply with shoot Ψ in J. monosperma, but not in P. edulis. The contrasting behaviour of J. monosperma and P. edulis reflects differences in their capacity for homeostatic regulation of turgor that may be representative of aniso‐ and isohydric species in general, and may also be associated with the greater capacity of J. monosperma to withstand severe drought.     

New Zealand triplefin fishes (family Tripterygiidae): contrasting population structure and mtDNA diversity within a marine species flock

Triplefin fishes (Family Tripterygiidae) dominate the New Zealand temperate coastal fish fauna in diversity (26 endemic species, 14 genera). Most species appear to have evolved as a local radiation and mostly occupy sympatric distributions throughout New Zealand. To investigate the forces driving current gene‐flow patterns and past evolutionary histories, we searched for common patterns of population genetic subdivision within eight species sampled throughout their distributions [mitchochondrial DNA (mtDNA) control region, n = 1086]. We hypothesised that common phylogeographical and population differentiation patterns would reveal past or ongoing physical processes, with differences reflecting stochastic or species‐specific processes. Striking differences between species were apparent, with strong phylogeographical structure detected in Grahamina capito and the estuarine species G. nigripenne. G. capito fell into three distinct geographically restricted lineages. G. nigripenne largely separated into northern and southern lineages (Φ_ST 0.834). Strong population structuring and isolation by distance was evident in Bellapiscis medius, B. lesleyae and Forsterygion lapillum (Φ_ST 0.686, 0.436 and 0.115, respectively). High gene flow was apparent in G. gymnota and Ruanoho whero, and F. varium. However, for the latter species, isolation was apparent with samples collected from the offshore Three Kings Islands. Overall, a strong relationship was found between habitat depth and population structure among species, and species inhabiting shallower water habitats showed lower genetic diversity with higher levels of population subdivision. High‐latitude populations generally showed low haplotype and nucleotide diversity. These data suggest that processes resulting from intraspecific differences in habitat preference, climatic histories and/or larval ecologies have subdivided populations of shallow water triplefin species.     

Development of 19 microsatellite loci for Swainson's hawks (Buteo swainsoni) and other buteos

We developed 26 Swainson's hawk (Buteo swainsoni) microsatellite primers from CA, AAT, CATC and GAGAA enriched genomic libraries. Primers were tested in 357 Swainson's hawks from western North America as well as seven other Buteo species. These markers will have broad application in investigations of Buteo population structure and genetic diversity.     

Volatiles produced by soil‐borne endophytic bacteria increase plant pathogen resistance and affect tritrophic interactions

Volatile organic compounds (VOCs) released by soil microorganisms influence plant growth and pathogen resistance. Yet, very little is known about their influence on herbivores and higher trophic levels. We studied the origin and role of a major bacterial VOC, 2,3‐butanediol (2,3‐BD), on plant growth, pathogen and herbivore resistance, and the attraction of natural enemies in maize. One of the major contributors to 2,3‐BD in the headspace of soil‐grown maize seedlings was identified as Enterobacter aerogenes, an endophytic bacterium that colonizes the plants. The production of 2,3‐BD by E. aerogenes rendered maize plants more resistant against the Northern corn leaf blight fungus Setosphaeria turcica. On the contrary, E. aerogenes‐inoculated plants were less resistant against the caterpillar Spodoptera littoralis. The effect of 2,3‐BD on the attraction of the parasitoid Cotesia marginiventris was more variable: 2,3‐BD application to the headspace of the plants had no effect on the parasitoids, but application to the soil increased parasitoid attraction. Furthermore, inoculation of seeds with E. aerogenes decreased plant attractiveness, whereas inoculation of soil with a total extract of soil microbes increased parasitoid attraction, suggesting that the effect of 2,3‐BD on the parasitoid is indirect and depends on the composition of the microbial community.     

A phylogeny of sand flies (Diptera: Psychodidae: Phlebotominae), using recent Ethiopian collections and a broad selection of publicly available DNA sequence data

Sand flies in the psychodid subfamily Phlebotominae carry important human pathogens in the trypanosomatid protozoan genus Leishmania (Cupolillo). Despite the fact that hundreds of sequences for this group are now publicly available, they constitute different sets of taxa and genetic markers. Integrating these data to construct a molecular phylogeny of the family is a significant bioinformatics challenge. We used sequences of eight markers obtained from freshly collected sand flies from Ethiopia and combined them with over 1300 publicly available sequences, performing a combined analysis after generating single terminal sequences from ancestral reconstructions for some individual markers. The resulting phylogeny had 113 terminals and recovered Phlebotominae and certain species groups as monopheletic. Although the 20 outgroups in Psychodinae were recovered as a well‐resolved clade with bootstrap support for many internal clades, Phlebotominae was recovered as several lineages with unclear relationships among them. However, phlebotomines clustered by geographic region, the most notable being all the New World species except Brumptomyia (Galati), which were recovered as monophyletic. Our phylogeny suggests a Sub‐Saharan African or South Asian origin for the subfamily, which subsequently expanded to the north and west, and eventually to the New World. Supported species groups are often composed of widespread species with overlapping ranges. This result highlights the need for a large increase in the amount and diversity of molecular sequence data, and a broad selection of terminals, to test taxonomic hypotheses and examine speciation processes in this important group of flies.     

Behavioural plasticity in the stinging act of female ectoparasitoids

Abstract. The plasticity of the stinging behaviour of female Eupelmidae ( Eupelmus vuilleti Crawford, E. orientalis Crawford Hymenoptera: Eupelmidae) was analysed through the interrelationships of a parasitic community living on larval stage of Callosobruchus maculatus Fabricius (Coleoptera: Bruchidae). In traditional African grainstores, Eupelmus females have at their disposal all the larval stages of their host. Their exploitation is revealed by the sting observed on the host caused by the ovipositor of parasitoid females. This stinging behaviour begins immediately on the adult female's emergence, and thereafter there is a daily increase in the number of hosts stung. Stinging activity is linked to the age of the available hosts, but not all of the hosts available are exploited by the two species studied. This absence of total exploitation could indicate a threshold of activity in the stinging acts which could be in part linked to the secretion activity of the poison glands of parasitoid female.
In females of E. vuilleti and E.orientalis the stinging act is usually associated with egg-laying. The relationship between stinging and egg-laying is stronger in more advanced larval stages of the host.
In the presence of parasitized hosts, females of E. orientalis and E.vuilleti can exhibit hyperparasitism. The majority of larvae (i.e. primary parasitoid) that have been hyperparasitized have been stung and a large number of them are completely inactive. However, E. vuilleti females deposited their eggs in the available space of the pupation chamber of the host. The neonatal larvae from these scattered eggs could exploit any available host without the female having 'prepared the ground' at the time of egg-laying.
In Eupelmidae, all this happens as if there were a complementary action between the females and the neonate which could, if necessary, reinforce and/or compensate for the deficiencies in the host exploitation by the female.