Post-Soviet steppe management causes pronounced synanthropy in the globally threatened Sociable Lapwing Vanellus gregarius

Habitat associations and distribution of breeding Sociable Lapwings were examined in 2004–2008 in central Kazakhstan to develop and assess hypotheses relating to the species' decline and high conservation threat status. At a landscape scale, breeding colonies were strongly positively associated with villages and rivers. Habitat suitability models had very high predictive power and suggested that only 6.6–8.0% of the 30 000-km² study area was potentially suitable for Sociable Lapwings. Models developed to describe the spatial distribution of nests in one region of Kazakhstan in one year predicted well the distribution of nests in another region, suggesting good generality. At a colony scale, nests were most likely to be found in the most heavily grazed areas, with a high cover of animal dung and bare ground. Despite the low density of human settlements in the study area, most Sociable Lapwing nests were < 2 km from a village. Patterns of grazing were assessed by fitting GPS loggers to cattle. There was a strong positive correlation around villages between grazing intensity and the density of Sociable Lapwing nests, with clear evidence of a threshold of grazing density that needs to be reached before birds will breed. This high degree of synanthropy, perhaps unique in a critically endangered bird, is likely to result from post-Soviet changes in steppe management and offers both threats and opportunities to the species' conservation.     

Gene expression profiling: opening the black box of plant ecosystem responses to global change

The use of genomic techniques to address ecological questions is emerging as the field of genomic ecology. Experimentation under environmentally realistic conditions to investigate the molecular response of plants to meaningful changes in growth conditions and ecological interactions is the defining feature of genomic ecology. Because the impact of global change factors on plant performance are mediated by direct effects at the molecular, biochemical, and physiological scales, gene expression analysis promises important advances in understanding factors that have previously been consigned to the 'black box' of unknown mechanism. Various tools and approaches are available for assessing gene expression in model and nonmodel species as part of global change biology studies. Each approach has its own unique advantages and constraints. A first generation of genomic ecology studies in managed ecosystems and mesocosms have provided a testbed for the approach and have begun to reveal how the experimental design and data analysis of gene expression studies can be tailored for use in an ecological context.     

Resprouting responses of trees in a fire‐prone tropical savanna following severe tornado damage

Fire and windstorms can cause severe disturbance, but their consequences for trees may differ. Resprouting enables persistence through frequent and severe disturbance. To explore responses to an abnormal disturbance and evolutionary hypotheses about resprouting as an adaptation, we analysed patterns of resprouting in four taxa following a tornado in a tropical savanna (Kakadu National Park, northern Australia) that is frequently burnt but is rarely subject to severe windthrow. Resprouting (i.e. survival) rates varied markedly among taxa and damage types, from 35% in uprooted Acacia spp. (Mimosaceae) to over 90% in eucalypts (Myrtaceae) and Erythrophleum chlorostachys (Caesalpiniaceae) with persistent tertiary branches. Most resprouting was from the epicormic strand‐bank on the stem or branches. Across all taxa, greater architectural damage reduced resprouting rates. Damage was magnified by proximity to the centre of the tornado path, suggesting an additional effect of internal damage. Smaller trees, trees whose trunks were snapped below 2 m, and those closer to the tornado path were more likely to resprout basally or from the roots rather than epicormically, although in Acacia spp. these resprouting modes were positively correlated. We hypothesize that trees of fire‐prone savannas have evolved to grow rapidly out of the flame zone; this was supported by more detailed analyses of Eucalyptus tetrodonta suggesting that resprouts emerging nearer the ground grow faster. Resprouting at ground level may be a bet‐hedging strategy to spread the risk of mortality among multiple stems when elevated sprouting was not possible. We conclude that the adaptation of eucalypts to frequent fire does not jeopardize their survival (by comparison with the more generalist Acacia spp.) following severe windthrow, providing an example of ‘exaptation’ rather than trade‐off in fitness under contrasting stressors.     

Rising concentrations of atmospheric CO2 have increased growth in natural stands of quaking aspen (Populus tremuloides)

As atmospheric CO₂ levels rise, temperate and boreal forests in the Northern Hemisphere are gaining importance as carbon sinks. Quantification of that role, however, has been difficult due to the confounding effects of climate change. Recent large‐scale experiments with quaking aspen (Populus tremuloides), a dominant species in many northern forest ecosystems, indicate that elevated CO₂ levels can enhance net primary production. Field studies also reveal that droughts contribute to extensive aspen mortality. To complement this work, we analyzed how the growth of wild aspen clones in Wisconsin has responded to historical shifts in CO₂ and climate, accounting for age, genotype (microsatellite heterozygosity), and other factors. Aspen growth has increased an average of 53% over the past five decades, primarily in response to the 19.2% rise in ambient CO₂ levels. CO₂‐induced growth is particularly enhanced during periods of high moisture availability. The analysis accounts for the highly nonlinear changes in growth rate with age, and is unaffected by sex or location sampled. Growth also increases with individual heterozygosity, but this heterozygote advantage has not changed with rising levels of CO₂ or moisture. Thus, increases in future growth predicted from previous large‐scale, common‐garden work are already evident in this abundant and ecologically important tree species. Owing to aspen's role as a foundation species in many North American forest ecosystems, CO₂‐stimulated growth is likely to have repercussions for numerous associated species and ecosystem processes.     

Shrub encroachment in North American grasslands: shifts in growth form dominance rapidly alters control of ecosystem carbon inputs

Shrub encroachment into grass-dominated biomes is occurring globally due to a variety of anthropogenic activities, but the consequences for carbon (C) inputs, storage and cycling remain unclear. We studied eight North American graminoid-dominated ecosystems invaded by shrubs, from arctic tundra to Atlantic coastal dunes, to quantify patterns and controls of C inputs via aboveground net primary production (ANPP). Across a fourfold range in mean annual precipitation (MAP), a key regulator of ecosystem C input at the continental scale, shrub invasion decreased ANPP in xeric sites, but dramatically increased ANPP (>1000 g m⁻²) at high MAP, where shrub patches maintained extraordinarily high leaf area. Concurrently, the relationship between MAP and ANPP shifted from being nonlinear in grasslands to linear in shrublands. Thus, relatively abrupt (<50 years) shifts in growth form dominance, without changes in resource quantity, can fundamentally alter continental-scale pattern of C inputs and their control by MAP in ways that exceed the direct effects of climate change alone.     

Ovipositor internal microsculpture and other features in doryctine wasps (Insecta, Hymenoptera, Braconidae)

Detailed ovipositor morphology has been investigated in representatives of 81 of the more than 120 genera of the parasitic wasp subfamily Doryctinae. Potentially phylogenetically informative variation was found in the microsculpture of the egg canal wall and the presence and degree of development of the valvillus. In all the genera, a socketed seta arises from below each member of the line of ctenidia (comb-like scales) distal to the valvillus (or valvillar region). These subctenidial setae are modified in two groups of genera. In the Holcobraconini (= Odontobraconini) together with the genera Acanthodoryctes, Binarea, Monarea , and Liobrucon , the setae are extremely flattened producing overlapping leaflet-like structures. In some of these, groups of leaflets are further modified to form fans that protrude into the egg canal. In Schlettereriella and Leptospathius the basal seta is highly branched and rather flattened and may serve a similar function to the valvillus which in these two genera is extremely reduced. In Doryctes and Neodoryctes , there is a distinctive type of bar-like sculpture anterior to the valvillus and a single large crescentic bar posterior to the valvillus. These modifications are suggested as possible synapomorphies (in lieu of an analysis) for their respective groups of genera. Several other characters are also described and illustrated. CO 1998 The Norwegian Academy of Science and Letters     

Two new genera and species of Braconinae (Insecta, Hymenoptera, Braconidae)from Brunei

Fuvihracon gen.n. (typc-species: Fuvibracon gauldi sp.n.) and Spurhulibrucon (type-species: Sparhulibracon dayi sp.n.), both lrom Brunei, are described and illustrated. The relationships of the two new genera and of the Carnpyloneurus Szépligeti and Chelonogaslra Ashmead generie groups are discussed.     

Morphology of the antenna cleaner in the Hymenoptera with particular reference to non-aculeate families (Insecta)

An electron microscopic survey of antenna cleaner morphology, mainly in non-aculcate Hymenoptera, is presented. Modified, scale- or paddle-shaped setae on the fore basitarsus were found to be widely distributed throughout the order, but were particularly well developed in the Xyeloidea. Megalodontoidea, Blasticotomidae, Siricoidca, Orussoidea, Cephoidea and Chalcidoidea. as well as in the aculeate family Formicidae. A comb of fine setae on the fore basitarsus was present in all Apocrita, with the exception of the Trigonalyoidea, Evaniidae, and some families of Chalcidoidea, but among the symphytan families was present only in the Orussidae. Members of the symphytan family, Anaxyelidae have a distinct line of discrete setae in the same position as the fine comb of the Orussidae and apocritans which we term a protocomb; members of the Cephidae also show an indication of a protocomb, in the form of a line of more widely spaced, erect setae, that could form part of the same transition series. Members of the Trigonalyoidea and of the Evaniidae have no comb of fine setae but do possess one or more rows of highly modified, plate-like structures on the fore basitarsi.     

Molecular evidence of cycad seed predation by immature Aulacoscelidinae (Coleoptera: Orsodacnidae)

Adult beetles in the small subfamily Aulacoscelidinae (superfamily Chrysomeloidea) are known to feed on the foliage and juices of New World cycads (Order Cycadales; family Zamiaceae), but the habits of larvae have long remained a mystery. We provide the first direct evidence that Aulacoscelidinae larvae feed on and develop within the megagametophyte of the Mesoamerican cycad, Dioon merolae (Zamiaceae). Phylogenetic analyses based on partial DNA sequences from 3 genes recover a cycad seed‐feeding larva proposed to belong to Aulacoscelidinae. These observations reveal a more intimate feeding relationship between Aulacoscelidinae and their New World cycad host plants than was previously recognized. Further, adult Aulacoscelidinae have long been noted to resemble Jurassic fossil chrysomeloids in the extinct subfamily Protoscelidinae. The molecular, morphological, ecological and fossil data reported herein are broadly compatible with an early association between Aulacoscelidinae and their gymnosperm hosts.