Winter energy deficits and the importance of fruit versus insects in a tropical island bird population

The sedentary population of 200 to 500 silver-eyes on Heron Island, Australian Great Barrier Reef, experiences high mortality during the winter non-breeding season. The omnivorous silvereyes feed mainly on small insects gleaned from foliage, and on fruits, especially the fig Ficus opposita. Estimates of the energy content of food items reveal that small insects (2–5 mm long) provide little assimilable energy (9 J), whereas large insects (>8 mm) and bites of fig provide most assimilable energy (217 J and 181 J respectively). An analysis of the average daily intakes and expenditures (estimated by the time-budget method) for three sampling occasions showed that the rates of insect consumption (10,15 and 11 kJ day^-1) were significantly less than the energy requirements (37, 38 and 37 kJ day^-1). While many individuals may have been able to balance their energy budgets by eating figs, the calculated fruit intake rates (38, 9 and 0.5 kJ day^-1 respectively), together with high inter-individual variation in fig consumption, suggest that figs were often in short supply. The birds visited fig trees most frequently during the first 2 h after sunrise, and the feeding success rate in fig trees (approximately 20% of visits successful) during this time was significantly greater than that during the rest of the day (approximately 10% of visits successful). Alternative hypotheses for these patterns, based on protein requirements, on diurnal rhythms imposed by insect availability, or on satiation, are considered and rejected. These results indicate that the pre-breeding population size is limited by winter energy shortage, the extent of which is dependent on the size and phenology of the fig crop. Natural selection should favour individual strategies for maximization of net energy intake.     

Effects of cyanogenesis in bracken fern (Pteridium aquilinum) on associated insects

Abstract. 1. The relationship between cyanogenesis in bracken fern and the insect fauna feeding on the plant was investigated over a 3 year period. The most common insects between May and July, while cyanide levels were high, were the sawflies Strongylogaster impressata Provancher, S.multicincta Norton, Aneug-menus fzavipes (Norton), the aphid Macrosiphum euphorbiae (Thomas) and a microlepidopteran species of Monochroa .
2. Collections of insects from cyanogenic and acyanogenic fronds showed significantly fewer sawflies on the cyanogenic fronds. The aphid and the microlepidopteran were randomly distributed with respect to cyanogenicity.
3. Feeding tests for two of the sawfly species ( Simpressata and Smulticincta ) showed that larvae grew more slowly and had a higher mortality when raised on cyanogenic fronds than on acyanogenic ones.
4. Field collected cyanogenic bracken fronds were found to have sustained less damage from chewing herbivores compared with acyanogenic fronds.     

Risk Perception Mapping: Using Ethnography to Define the Locally Affected Population for a Low-Level Radioactive Waste Storage Facility in Michigan

The concept of a "risk perception shadow" (RPS) has been suggested to describe the geocultural area in which a locally affected population perceives itself to be at risk from a proposed project. Generally such projects involve potentially dangerous substances or activities. The initial conceptualization of an RPS was developed during the social assessment of a proposed Superconducting Super Collider (SSC) in Michigan. This article describes an effort at mapping and analyzing an RPS produced by a proposal to site a low-level radioactive waste (LLRW) storage facility in Michigan. A unique sampling technique was used to define the boundary of the generally concentric RPS. Risk perception mapping (RPM) is suggested as a rapid and efficient method for defining locally affected populations for social impact studies.     

Infraspecific variation and phylogeography of the high-polyploid Iberian endemic Anthoxanthum amarum Brot. (Poaceae; Pooideae) assessed by random amplified polymorphic DNA markers (RAPDs) and morphology

High morphological and ecological diversity has been observed in the north-west Iberian Peninsula endemic Anthoxanthum amarum Brot., for which two different morphotypes (northern and southern) have been described on the basis of qualitative traits and geographical origin. In the present study, a combined molecular and morphological method was applied to ten populations of this species with the following aims: (1) to assess whether the variation observed was taxonomically meaningful; (2) to assess the influence of the environment on the variation in the morphological characters; and (3) to track the potential phylogeographical information deduced from our random amplified polymorphic DNA marker (RAPD) data in order to draw inferences about the past history of this species in the north-west Iberian Peninsula. To achieve these aims, 26 macromorphological characters were recorded in 279 specimens, and 77 RAPD phenotypes were identified in the 79 plants studied. The association analyses performed using the morphological and molecular data showed that no clear separation existed between the morphs, and a strong correlation between qualitative characters and the environment was detected. Moreover, both the multivariate analyses and the assignment test based on RAPD data revealed that the genetic variation was hierarchically structured, and three genetically distinct groups could be identified. Two of these clusters might correspond to different expansion routes proposed in the literature for different plant species in the north-west Iberian Peninsula.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 179–192.     

Determinants of preferred intertidal feeding habitat for Eastern Curlew: A study at two spatial scales

Abstract Broadscale habitat use by Eastern Curlews (Numenius madagascariensis) in their non‐breeding range in eastern Australia was assessed using low tide surveys on feeding grounds, where 60 skilled volunteers made repeated counts of the birds on intertidal flats, across 41% (9500 ha) of the intertidal habitat within Moreton Bay, Australia. We analysed 32 defined sections of intertidal flat, of roughly equal area (mostly 200–400 ha), which varied greatly in their curlew density (2–47 birds per 100 ha) and also in substrate and other environmental features. Sites with the least resistant substrates had densities three times those with the most resistant substrates. Of 10 environmental characteristics measured for each site, substrate resistance was the best predictor of curlew density (r² = 0.45). Characteristics that were poor predictors included distance to the nearest roost, level of human disturbance and distance to urban settlement. For a finer‐scale assessment, microhabitat use and feeding behaviour were recorded during low tide within 12 intertidal flats, which varied in size (23–97 ha), substrate, topography and other features. Across all flats, curlews strongly preferred to feed relatively close (0–50 m) to the low‐water line. They fed on a variety of substrates (including sand, sandy‐mud, mud and seagrass) in broadly similar proportions to their occurrence in the habitat. There was a statistically significant preference for sand, although its magnitude was not strong. These results indicate that curlews select habitat most strongly at a between‐flat rather than within‐flat scale.     

Damage caused by mistletoe Misodendrum punctulatum Banks Ex Dc. on architecture and radial growth of Nothofagus pumilio (Poepp. et Endl.) Krasser forests of southern Chile

Parasitic plants rely completely or partially on host plant, namely holoparasitic or hemiparasitic, respectively. The effect of parasitism on host plants is not fully known. Misodendrum punctulatum (Misodendraceae) is the most common hemiparasite species in the southernmost forests of Chile and Argentina, and it has been identified as an important sanitary problem in forestry. In this study we evaluated the M. punctulatum effect on growth rates and architecture of pure Nothofagus pumilio (Nothofagaceae) forests in southern South America (52°10′S; 71°55′W). We established three plots of 30 × 30 m, and 10 cores were extracted from diameter at breast height (d.b.h. = 1.3 m) from living trees in each plot, using increment borers. Tree rings were measured, and anova was used to compare the annual growth rate of both infected and uninfected N. pumilio. The results showed that N. pumilio trees severely infected by M. punctulatum reduce growth rates in contrast with uninfected individuals (P < 0.05). Besides, trees with high‐infection levels evidenced deterioration in its architecture, showing asymmetric and suppressed canopies, according to ad hoc numerical indexes. This study provides a starting point to understand the parasite–host relationship in the Patagonian forests of southern Chile.     

Diversification of Morpho butterflies (Lepidoptera,Nymphalidae): a re‐evaluation of morphological characters and new insight from DNA sequence data

This study compiles previously published morphological, colour and behavioural characters and includes new DNA sequence data for eight markers (one mitochondrial and seven nuclear) to re‐evaluate phylogenetic relationships and estimate times of divergence for Morpho butterflies using parsimony and Bayesian methods. We note an effect of missing data on phylogenetic inference and calculations of Partitioned Bremer Support. Morphology and DNA trees were moderately congruent, and the combined analyses of all data included elements of both sources. Both morphology and DNA support the monophyly of Morpho and the early separation of the sister pair M. marcus plus M. eugenia, but trees from different data sources are congruent mostly at derived nodes, and differ at several internal nodes. The analyses of combined data indicate that Morpho is composed of four clades each of which include one or more previously proposed subgenera. The subgenera Pessonia and Morpho were not monophyletic, and to address this issue we propose that Pessonia, syn.nov. be subsumed within Morpho. The ancestor of Morpho probably arose during the Oligocene, and most diversification seems to have occurred during the late Miocene. S‐DIVA analysis suggests eastern Andean region as the ancestral area for Morpho, and that the South American Atlantic Forest was colonized multiple times.