Using a common commensal bacterium in endangered Takahe as a model to explore pathogen dynamics in isolated wildlife populations

Predicting and preventing outbreaks of infectious disease in endangered wildlife is problematic without an understanding of the biotic and abiotic factors that influence pathogen transmission and the genetic variation of microorganisms within and between these highly modified host communities. We used a common commensal bacterium, Campylobacter spp., in endangered Takahe (Porphyrio hochstetteri) populations to develop a model with which to study pathogen dynamics in isolated wildlife populations connected through ongoing translocations. Takahe are endemic to New Zealand, where their total population is approximately 230 individuals. Takahe were translocated from a single remnant wild population to multiple offshore and mainland reserves. Several fragmented subpopulations are maintained and connected through regular translocations. We tested 118 Takahe from 8 locations for fecal Campylobacter spp. via culture and DNA extraction and used PCR for species assignment. Factors relating to population connectivity and host life history were explored using multivariate analytical methods to determine associations between host variables and bacterial prevalence. The apparent prevalence of Campylobacter spp. in Takahe was 99%, one of the highest reported in avian populations. Variation in prevalence was evident among Campylobacter species identified. C. sp. nova 1 (90%) colonized the majority of Takahe tested. Prevalence of C. jejuni (38%) and C. coli (24%) was different between Takahe subpopulations, and this difference was associated with factors related to population management, captivity, rearing environment, and the presence of agricultural practices in the location in which birds were sampled. Modeling results of Campylobacter spp. in Takahe metapopulations suggest that anthropogenic management of endangered species within altered environments may have unforeseen effects on microbial exposure, carriage, and disease risk. Translocation of wildlife between locations could have unpredictable consequences including the spread of novel microbes between isolated populations.     

Reproductive Success Increases with Local Density of Conspecif ics in a Desert Mustard (Lesquerella fendleri)

We investigated the effects of plant density on reproduction for an insect-pollinated desert mustard (Lesquerella fendleri [Brassicaceae]). Individual reproductive success, as measured by seeds per fruit, proportion of flowers setting fruit, and total seed production, increased with the density of conspecifics within 1 m. However, including the density of conspecifics at greater distances (1–3 m) did not significantly increase the amount of variation in reproductive success explained by the regression model. This implies that processes occurring on a scale of 1 m or less have important effects on reproduction. Total seed production also was greater for high-density plants than for otherwise similar plants with a low-density of conspecifics. We argue that increased pollinator visitation is the most likely cause of this facilitation and that investigations of the effects of rarity on reproductive success should directly consider density along with more commonly used attributes such as population size and fragmentation.     

Measurement of driving patterns of older adults using data logging devices with and without global positioning system capability

BACKGROUND: Methods to study driving patterns and exposure of older drivers have typically relied on surveys or driving diaries. Electronic data logging devices may offer a reliable, alternative method of measuring driving exposure, and global positioning system (GPS) technology may be able to provide further information about driving patterns. OBJECTIVES: The aim of this study was to compare a driving diary with two electronic data logging devices, one of which had GPS capability, in order to identify which method best assesses the driving exposure and habits of older drivers as well as the method most acceptable to study participants. METHOD: In this prospective cohort study we recruited 20 participants aged 70 years or more (mean 78; range 70-85) (15 men and 5 women). The participants' driving patterns were recorded for one week with an electronic data logging device with GPS (FleetPulse), followed by recording for a further week with an electronic data logging device without GPS (CarChip). During both time periods the subjects also completed a standard driving diary. RESULTS: More comprehensive information, including braking and acceleration patterns, duration of driving time, time of day, and maximum speeds, was collected with the electronic devices than with the driving diary. There was excellent correlation between the driving diary data and those obtained with the CarChip (r = 0.9; p < 0.01). The correlation between the driving diary data and the FleetPulse data was moderate (r = 0.56; p = 0.02). The subjects clearly preferred the electronic monitoring devices over the driving diary. GPS data were able to demonstrate driving routes. CONCLUSIONS: Electronic data logging devices are a valid method for recording the driving patterns of older adults. These devices also reduce burden and improve the completeness of data.     

Why do house-hunting ants recruit in both directions?

To perform tasks, organisms often use multiple procedures. Explaining the breadth of such behavioural repertoires is not always straightforward. During house hunting, colonies of Temnothorax albipennis ants use a range of behaviours to organise their emigrations. In particular, the ants use tandem running to recruit naïve ants to potential nest sites. Initially, they use forward tandem runs (FTRs) in which one leader takes a single follower along the route from the old nest to the new one. Later, they use reverse tandem runs (RTRs) in the opposite direction. Tandem runs are used to teach active ants the route between the nests, so that they can be involved quickly in nest evaluation and subsequent recruitment. When a quorum of decision-makers at the new nest is reached, they switch to carrying nestmates. This is three times faster than tandem running. As a rule, having more FTRs early should thus mean faster emigrations, thereby reducing the colony’s vulnerability. So why do ants use RTRs, which are both slow and late? It would seem quicker and simpler for the ants to use more FTRs (and higher quorums) to have enough knowledgeable ants to do all the carrying. In this study, we present the first testable theoretical explanation for the role of RTRs. We set out to find the theoretically fastest emigration strategy for a set of emigration conditions. We conclude that RTRs can have a positive effect on emigration speed if FTRs are limited. In these cases, low quorums together with lots of reverse tandem running give the fastest emigration.     

Size and structure of a photographically identified population of manta rays <Emphasis Type="Italic">Manta alfredi</Emphasis> in southern Mozambique

The size and structure of a photographically identified population of reef manta ray, Manta alfredi, were examined at aggregation sites over a four-year period in southern Mozambique. The use and standardisation of photo-ID techniques was examined as a minimally-intrusive means to study this species. Using these techniques, we report on the size, structure and seasonality of this population of M. alfredi. In total, 449 individuals were identified during this time period, 40.5% of which were re-sighted on at least one occasion. The longest period between re-sighting events was 1,252 days. During the study period, annual population size estimates for M. alfredi ranged from 149 to 454 individuals. The superpopulation size estimate for the entire study period was 802 individuals, the first reported for M. alfredi at a monitored aggregation site. A highly significant sex bias was evident with a female:male ratio of 3.55:1. The majority of rays (89.9% males; 49.7% females) were considered mature, with most individuals between 3.0 and 4.9 m in disc width. Manta alfredi were observed at the study sites in each month of the calendar year. The maximum number of individual rays seen per dive was 30. Large numbers of rays (20 + per dive) were seen in the months of November, December and January, which coincide with the breeding season. Natural markings were unique to individuals and did not change substantially with time, which provided further support for their use in the identification of individual M. alfredi over multiple years. Multiple re-sightings of individual M. alfredi suggest that many individuals in this population exhibit site fidelity to the examined aggregation sites. As target subsistence fishing for M. alfredi exists along the Mozambican coastline, management efforts to monitor and prevent overexploitation at these critical habitats should be a priority.     

A review of: “Environmental Analysis Using Chromatography Interfaced with Atomic Spectroscopy”

Edited By Roy M. Harrison and Spyridon Rapsomanikis. Published By Ellis Horwood Ltd, Chichester: Price £59.50. 12 Chapters, 370 Pages.