Radio-telemetric evidence of migration in the gregarious but not the solitary morph of the Mormon cricket (Anabrus simplex: Orthoptera: Tettigoniidae)

 The Mormon cricket, Anabrus simplex, is one of just a few species of katydids (or bushcrickets, Orthoptera: Tettigoniidae) that, like migratory locusts, appear to have solitary and migratory morphs. Using radio telemetry we studied movements of individuals of two morphs of this flightless species. Individuals within each migratory band had similar rates of movements along similar directional headings whereas solitary individuals moved little and showed little evidence of directionality in movement. Our results also add to other recent radio-telemetry studies showing that flightless insects of 1–2 g in mass can be tracked successfully using these methods. Received: 28 February 2000 / Accepted in revised form: 19 June 2000     

Estimates of the association between ozone and asthma hospitalizations that account for behavioral responses to air quality information

Behavioral responses to information about forecasted air quality may introduce systematic measurement error in pollution exposure, leading to biased estimates of the impact of pollution exposure on health. This paper estimates the statistical association between ambient ozone concentrations and asthma hospitalizations in Southern California while accounting for potential avoidance behavior in response to forecasted air quality. Data on asthma hospital admissions were merged with observed and forecasted air quality and meteorological data at the daily level for the years 1989–1997. A distributed lag Poisson generalized linear model allowing for overdispersion was estimated. Accounting for potential responses to information about pollution leads to significantly larger estimates of the relationship between ozone concentrations and asthma hospital admissions, particularly for susceptible populations. Individuals take substantial actions to reduce exposure to ozone; estimates of the concentration–response function for ozone that ignore these actions are biased towards the null and may significantly understate the costs to society from ozone concentrations.     

Nest defence by song sparrows: methodological and life history considerations

Summary Several aspects of nest defence behavior were investigated in song sparrows (Melospiza melodia) in eastern Ontario. Two independent tests were made of the hypothesis that the increase in nest defence observed through a nesting attempt is due to the birds becoming familiar with the nest threat, rather than because the nest contents increase in value to the parents. Neither test supported the hypothesis. As predicted by life history theory for species with age-independent mortality, males did not defend their nest more vigorously as they become older. Parents defended their nests less vigorously through the breeding season, contrary to the expected pattern of increased nest defence in response to declining renesting potential. This result may be attributable to a decline in offspring value through the breeding season. Nest defence behavior of mated individuals was positively correlated, independent of factors such as offspring age, renesting potential and brood size. From this result it is proposed that a source of variation in nest defence behavior may be individuals basing their own response on their mate's response in a positive feedback fashion. Males defended nests less vigorously than females, consistent with the expectation that males have lower certainty of parentage in the offspring. It is proposed that variation in paternal uncertainty could contribute to the unexplained variation reported in nest defence studies.     

Role of Genetic Background in the Success of Reintroduced Peregrine Falcons

Abstract: Peregrine Falcons (    Falco peregrinus ) of seven subspecies from four continents were bred in captivity, and approximately 1173 of their progeny were released in the midwestern United States and adjacent regions of Ontario and Manitoba in an attempt to replace the original population that was extirpated by chlorinated hydrocarbon poisoning in the 1950s. We analyzed the success of individuals of the different subspecies introduced to the Midwest. Five of the seven subspecies released have contributed to the current breeding population. Subspecies of breeding Peregrine Falcons were equally represented when breeding birds of high productivity were compared with less prolific breeders. The subspecific makeup of the breeding population did not differ significantly from that of the released population, suggesting that adaptability in this species was sufficient to override genetic differences between subspecies. Peregrines of widely different genetic stocks have thrived after release, making substantial genetic contributions to the new population.     

Travelling without a helmet: tourists' vulnerabilities and responses to disasters in Indonesia

Tourists are particularly vulnerable when natural disasters occur in regions that they are visiting. It is assumed that they lack awareness and understanding of the actions that they need to take in such circumstances. This study examines the responses of tourists in times of disaster, building on empirical data collected through large‐scale surveys conducted in Bali and Yogyakarta, Indonesia, in 2015. Both are important tourist destinations in the country that have suffered major disasters in recent years. The different types of responses to these events are framed using a grid/group analysis stemming from cultural theory. The study resulted in three key findings: (i) current disaster management planning largely follows a single rationale; (ii) tourists are not a homogeneous group, but rather a complex, diverse, and dynamic body of stakeholders; and (iii) the focus of disaster management planning should shift from a single rationale to a polyrational methodology. Disaster managers need to consider, therefore, these different aspects in the context of preparedness.     

Distribution,habitat preferences and behaviour of the critically endangered Maltese top-shell <Emphasis Type="Italic">Gibbula nivosa</Emphasis> (Gastropoda: Trochidae)

The Maltese top-shell, Gibbula nivosa Adams 1851, is a critically endangered marine trochid gastropod endemic to the Maltese Islands (central Mediterranean). Previously unrecorded live since 1981, rediscovery of this species in 2006 has enabled the collection of basic biological data for the first time, based on a population in Sliema Creek. The field distribution and habitat preferences of G. nivosa were investigated via stratified random sampling, while aspects of its behaviour were studied through laboratory experiments. Gibbula nivosa occurred primarily in near-homogeneous or homogeneous infralittoral cobble/pebble beds, at an overall density of 17.6 ± 25.0 SD individuals m⁻²; however, large spatial and temporal variations in abundance were recorded. The snails did not exhibit gregarious behaviour and the slightly clumped dispersion pattern noted in the field appeared to result from patchiness of the habitat. Recruitment was observed in post-summer months, which, together with data on shell-size distributions, suggests that G. nivosa spawns in early summer and attains adult size (maximum shell width ~9 mm) in less than 1 year. Gibbula nivosa showed a circadian activity pattern with nocturnal foraging involving indiscriminate ingestion of particles browsed off the substratum; observations on responses to four potential predators suggest that nocturnal activity may have evolved in response to diurnal predation. Historical records of snail occurrence and the present study suggest that population declines of G. nivosa in the past were probably related to habitat alteration as a result of anthropogenic pressure.     

Evaluation of Water Quality in the Chillán River (Central Chile) Using Physicochemical Parameters and a Modified Water Quality Index

The Chillán River in Central Chile plays a fundamental role in local society, as a source of irrigation and drinking water, and as a sink for urban wastewater. In order to characterize the spatial and temporal variability of surface water quality in the watershed, a Water Quality Index (WQI) was calculated from nine physicochemical parameters, periodically measured at 18 sampling sites (January–November 2000). The results indicated a good water quality in the upper and middle parts of the watershed. Downstream of the City of Chillán, water quality conditions were critical during the dry season, mainly due to the effects of the urban wastewater discharge. On the basis of the results from a Principal Component Analysis (PCA), modifications were introduced into the original WQI to reduce the costs associated with its implementation. WQI_DIR2 and WQI_DIR, which are both based on a laboratory analysis (Chemical Oxygen Demand) and three (pH, temperature and conductivity), respectively, four field measurements (pH, temperature, conductivity and Dissolved Oxygen), adequately reproduce the most important spatial and temporal variations observed with the original index. They are proposed as useful tools for monitoring global water quality trends in this and other, similar agricultural watersheds in the Chilean Central Valley. Possibilities and limitations for the application of the used methodology to watersheds in other parts of the world are discussed.     

Polychlorinated biphenyls in marine sediments from the southern North Sea and Scheldt estuary: a ten-year study of concentrations, patterns and trends

The paper reports the concentrations and patterns of CBs in sediments of the Belgian part of the southern North Sea and the Scheldt estuary for the period 1991-2001. The long-term analytical performance was well within the quality assurance boundaries set at the outset of the study and is consistent with the state of the art for this type of analysis. The CB concentrations (given as the median of the sum of IUPAC Nos 28, 52, 101, 118, 138, 153 and 180) vary between 0.1 microg kg(-1) and 50 microg kg(-1) dry weight in the total sediment and it could be demonstrated that CB patterns in the fine fraction of the sediment were closely similar throughout the investigated area. Isolation of the fine fraction (<63 microm) by sieving can be regarded as a physical normalisation to reduce the differences in sediment granulometric composition. It allows for a better understanding of CB distribution and patterns and improves the trend analysis. A significant downward trend could not be found at any of the stations, which suggests that CB levels have not been changing in the area of interest in the past decade.     

Extra-pair paternity and the opportunity for sexual selection in a socially monogamous bird (Dendroica petechia)

We used multi-locus DNA fingerprinting to characterise the genetic mating system of the socially monogamous yellow warbler (Dendroica petechia). Over 2 years there were no instances of brood parasitism, but 59% of families (n = 90) contained extrapair sired young and 37% of offspring (n = 355) were of extra-pair paternity. Most hypotheses for extra-pair mating in monogamous species assume a paternity benefit to extra-pair sires, and focus on the benefit(s) to females. However, the assumption of male benefit has been little tested. Among yellow warblers, known extra-pair sires were just as likely to be cuckolded as any male in the population, and there was at least one reciprocal exchange of extra-pair paternity. Nevertheless, among known extra-pair sires, the paternity gains from extra-pair paternity were, on average, greater than the losses in their own families. These results show there is a paternity benefit to certain males. However, the benefit is not absolute but relative and therefore more difficult to measure. The results also suggest that patterns of extra-pair fertilisation are not determined by female choice alone. Most confirmed extra-pair mates were territorial neighbours, but some resided as far as three territories apart, and greater spatial separation was implied in other cases. Thus, the opportunity for extra-pair mating is great. We estimate that as a result of extra-pair fertilisations, variance in male mating success is increased somewhere between 3-fold and 15-fold over that which would result from within-pair reproduction alone. These findings affirm the potential importance of extra-pair reproduction for sexual selection in monogamous species and they support earlier suggestions that extra-territorial forays by male yellow warblers are for the purpose of extra-pair mating.