Characteristics of Central American brocket deer resting sites in a tropical mountain cloud forest in eastern Mexico

The Central American brocket deer is a vulnerable species. Geographically isolated populations have been affected by poaching and habitat fragmentation, leading to local extinctions. It is therefore important to understand this species’ habitat characteristics, particularly of resting sites, which play a crucial role in survival and fitness. We describe the characteristics and distribution patterns of Central American brocket deer resting sites at the microhabitat and landscape scales in San Bartolo Tutotepec, Hidalgo, México. We conducted eight bimonthly field surveys between November 2017 and March 2019, consisting of 32 transects of 500 m length to search for fecal pellets, footprints, scrapes, and browsed plants. At each resting site we identified, we measured canopy closure, horizontal thermal cover, protection from predators for fawns and adults, escape routes, slope from the ground, presence of scrapes, cumulative importance value of the edible plant species, and distance from the resting site to the nearest water resource to characterize the site at the microhabitat scale. At the landscape scale, we identified the type of biotope, elevation, aspect, and slope. We compared all of these parameters from resting sites with a paired randomly selected site to serve as a control. We performed a multiple logistic regression to identify the parameters associated with the resting sites and a point pattern analysis to describe their distribution. We characterized 43 resting sites and their corresponding control plots. At the microhabitat scale, resting sites were associated with higher vertical thermal cover, more concealment cover, more escape routes, more edible plant species, higher slope from the ground, and closer distance to water resources. At the landscape scale, resting sites were associated with beech forest, oak forest, secondary forest, and ravine biotopes and negatively associated with pine forest, houses, and roads. Resting sites had an aggregated spatial pattern from 0 to 900 m, but their distribution was completely random at larger scales. Our study revealed that Central American brocket deer selected places with specific characteristics to rest, at both microhabitat and landscape scales. We therefore suggest that existing habitat be increased by reforesting with native species—particularly Mexican beech forest and oak forest—to improve the deer’s conservation status in the study area.

Carried away by a moonlight shadow: activity of wild boar in relation to nocturnal light intensity

An increase of nocturnal activity of ungulate species may represent a compensatory opportunity for energy intake, when activity in daylight is hindered by some disturbance events (e.g. hunting or predation). Therefore, mostly-diurnal and crepuscular species may be active in bright moonlight nights whereas others may shift their diurnal activity towards darkest nights to limit their exposure to predators. In natural and undisturbed conditions, the wild boar may be active both during the day and the night, with alternating periods of activity and resting. In this work, we tested whether activity patterns of wild boar, a species with poor visive abilities, were dependent on moon phases and environmental lightening. We aimed to assess if nocturnal activity could be better explained by variations of the lunar cycle or by the variations of environmental lightening conditions, evaluated by means of different measures of night brightness. Data were collected through camera-trapping in Central Italy in 2019–2020. Despite the poor visive abilities of the wild boar, we observed that this ungulate significantly reduced their activity by avoiding the brightest nights. In our study area, the wild boar has to cope with both human pressure (i.e. mostly hunters and poachers) and predation by the grey wolf. Furthermore, the nocturnal activity of wild boar peaked in mid-Autumn, i.e. when hunting pressure is the highest and when leaf fall may bring wild boar to range for long distances to find suitable resting sites for diurnal hours.

Efficacy of targeted indoor residual spraying with the pyrrole insecticide chlorfenapyr against pyrethroid-resistant Aedes aegypti

Background There is an increased need to mitigate the emergence of insecticide resistance and incorporate new formulations and modes of application to control the urban vector Aedes aegypti. Most research and development of insecticide formulations for the control of Ae. aegypti has focused on their peridomestic use as truck-mounted ULV-sprays or thermal fogs despite the widespread knowledge that most resting Ae. aegypti are found indoors. A recent modification of indoor residual spraying (IRS), termed targeted IRS (TIRS) works by restricting applications to 1.5 m down to the floor and on key Ae. aegypti resting sites (under furniture). TIRS also opens the possibility of evaluating novel residual insecticide formulations currently being developed for malaria IRS. Methods We evaluated the residual efficacy of chlorfenapyr, formulated as Sylando 240SC, for 12 months on free-flying field-derived pyrethroid-resistant Ae. aegypti using a novel experimental house design in Merida, Mexico. On a monthly basis, 600 female Ae. aegypti were released into the houses and left indoors with access to sugar solution for 24 hours. After the exposure period, dead and alive mosquitoes were counted in houses treated with chlorfenapyr as well as untreated control houses to calculate 24-h mortality. An evaluation for these exposed cohorts of surviving mosquitoes was extended up to seven days under laboratory conditions to quantify “delayed mortality”. Results Mean acute (24-h) mortality of pyrethroid-resistant Ae. aegypti ranged 80–97% over 5 months, dropping below 30% after 7 months post-TIRS. If delayed mortality was considered (quantifying mosquito mortality up to 7 days after exposure), residual efficacy was above 90% for up to 7 months post-TIRS application. Generalized Additive Mixed Models quantified a residual efficacy of chlorfenapyr of 225 days (ca. 7.5 months). Conclusions Chlorfenapyr represents a new option for TIRS control of Ae. aegypti in urban areas, providing a highly-effective time of protection against indoor Ae. aegypti females of up to 7 months.

Seasonal Prevalence and Host Preference of Some Medically Important Aedes Species of Doon Valley, India

In the recent past, several outbreaks of mosquito-borne diseases in Dehradun city make it necessary for a comprehensive understanding of man-vector contacts, disease transmission and determination of appropriate resting sites for adult mosquitoes. The study was conducted within the periphery of Dehradun city in Doon valley, Uttarakhand state, India consisting of eight (08) locations namely Sahaspur, Premnagar, Raipur, Karanpur, Sahastradhara, Dudhli, Doiwala and Rani Pokhri with the objective to analyze and assess the seasonal prevalence and host choice of the mosquitoes with special reference to Aedes species. Among the eight locations of the current study, Raipur registered the highest mosquito abundance (17%) trailed by Sahaspur (16%) and Karanpur (15%). A low abundance of mosquitoes was registered conjointly from Doiwala and Rani Pokhri areas (9% from each area). In these areas, the profile plots of the 2-way ANOVA displayed the highest variation for the data collected from human habitations followed by bovine sheds, whereas the lowest recorded variation was from the poultry. With regards to seasonal prevalence, the highest mosquito abundance was registered during the monsoon followed by the post-monsoon. In provender analysis, a total of 1912 blood meals were collected for antibody test among which 1851 were found positive, with the highest reaction with human antisera (57.75%), followed by bovine antisera (21.34%) and pigs antisera (4.97%). Ae. aegyptihad the highest Anthropophilic Index (A.I.) with 68.78%, followed by Ae. albopictus (64.89%) and Ae. vittatus (55.55%). However, Human Blood Predominance (H.B.P.) and Pure Human Blood Pervasiveness (P.H.B.P.) were found highest for Ae. albopictus with values 0.43 and 0.44 respectively. The results also show the seasonal prevalence and feeding habits of these vectors. This study would be helpful in formulating season-wise strategies for the control of Aedes vector mosquitoes in different eco-epidemiological situations.

Mosquito blood-feeding patterns and nesting behavior of American crows, an amplifying host of West Nile virus

Background Although American crows are a key indicator species for West Nile virus (WNV) and mount among the highest viremias reported for any host, the importance of crows in the WNV transmission cycle has been called into question because of their consistent underrepresentation in studies of Culex blood meal sources. Here, we test the hypothesis that this apparent underrepresentation could be due, in part, to underrepresentation of crow nesting habitat from mosquito sampling designs. Specifically, we examine how the likelihood of a crow blood meal changes with distance to and timing of active crow nests in a Davis, California, population. Methods Sixty artificial mosquito resting sites were deployed from May to September 2014 in varying proximity to known crow nesting sites, and Culex blood meal hosts were identified by DNA barcoding. Genotypes from crow blood meals and local crows (72 nestlings from 30 broods and 389 local breeders and helpers) were used to match mosquito blood meals to specific local crows. Results Among the 297 identified Culex blood meals, 20 (6.7%) were attributable to crows. The mean percentage of blood meals of crow origin was 19% in the nesting period (1 May–18 June 2014), but 0% in the weeks after fledging (19 June–1 September 2014), and the likelihood of a crow blood meal increased with proximity to an active nest: the odds that crows hosted a Culex blood meal were 38.07 times greater within 10 m of an active nest than > 10 m from an active nest. Nine of ten crow blood meals that could be matched to a genotype of a specific crow belonged to either nestlings in these nests or their mothers. Six of the seven genotypes that could not be attributed to sampled birds belonged to females, a sex bias likely due to mosquitoes targeting incubating or brooding females. Conclusion Data herein indicate that breeding crows serve as hosts for Culex in the initial stages of the WNV spring enzootic cycle. Given their high viremia, infected crows could thereby contribute to the re-initiation and early amplification of the virus, increasing its availability as mosquitoes shift to other moderately competent later-breeding avian hosts.

Notes on coexistence of closely related Leiobunum rupestre and L. subalpinum (Opiliones, Eupnoi, Sclerosomatidae)

Two closely related, syntopic species, Leiobunum rupestre and L. subalpinum, spend the day at apparently randomly distributed resting sites. In this preliminary research, we studied differences in their microclimatic preferences at a locality in the Pohorje Mts., Slovenia. We measured air temperature and relative humidity at individual resting sites, and found that L. subalpinum occupied a slightly wider air temperature-relative humidity ecospace as compared to L. rupestre. Individuals of L. rupestre rested at more humid sites than L. subalpinum. Regression analyses revealed that the presence of L. rupestre was most likely at resting sites with air temperature in the range of 12–17°C and with relative air humidity of 98.1%. In contrast, the presence of L. subalpinum was most likely at resting sites with air temperature 23.1°C and relative air humidity in the range of 65–85%. Nevertheless, microclimatic niches of both species overlapped almost completely, indicating that niche filtering may allow the coexistence of the two species.

Eave and swarm collections prove effective for biased captures of male Anopheles gambiae mosquitoes in Uganda

Background Traditional malaria vector sampling techniques bias collections towards female mosquitoes. Comprehensive understanding of vector dynamics requires balanced vector sampling of both males and females. Male mosquito sampling is also necessary for population size estimations by male-based mark-release-recapture (MRR) studies and for developing innovations in mosquito control, such as the male-targeted sterile insect technique and other genetic modification approaches. This study evaluated a range of collection methods which show promise in providing a more equal, or even male-biased, sex representation in the sample. Results Swarms were found at all study sites and were more abundant and larger at the peak of the wet season. Swarm sampling caught the most males, but when man/hour effort was factored in, sampling of eaves by aspiration was the more efficient method and also provided a representative sample of females. Grass-roofed houses were the most productive for eave collections. Overall few mosquitoes were caught with artificial resting traps (clay pots and buckets), although these sampling methods performed better at the start of the wet season than at its peak, possibly because of changes in mosquito ecology and an increased availability of natural resting sites later in the season. Aspiration of bushes was more productive at the peak of the wet season than at the start. Conclusions The results of this study demonstrate that eave aspiration was an efficient and useful male mosquito collection method at the study sites and a potentially powerful aid for swarm location and MRR studies. The methods evaluated may together deliver more sex-balanced mosquito captures and can be used in various combinations depending on the aims and ecological parameters of a given study.

Maliqua: A study within Malakit, a project on malaria and gold miners in French Guiana

Malaria is endemic in French Guiana, especially within the gold mining community working illegally. Gold miners travel to remote camps in the forest to carry out their activities, exposing themselves to the presumed contamination area. This paper presents the results of a qualitative case study of the Malakit project, a free distribution of self-diagnosis and self-treatment kits, along with appropriate training/information from health facilitators, at resting sites in Brazil and Suriname on the borders with French Guiana. This study documents how Malakit is part of the care trajectory of gold miners. The data was collected using three methods: 1) on-site observation; 2) semi-structured individual interviews (n=26); 3) semi-structured group interviews (n=2). The results inform us that Malakit responds to the need for treatment and facilitates access to care. Gold miners say they trust the facilitators and receive accurate explanations. The majority of participants find the kit easy to use and to carry and explanations given were sufficient, although some people needed to be reminded how to use it once in the forest. Results remind us that malaria among illegal gold miners in French Guiana is a question of social inequalities in health, where the interaction of the health, social, economic and political contexts of Brazil and French Guiana influence exposure to numerous risk factors. Thus, malaria intervention practices such as Malakit cannot be carried out without considering the complexity generated by social inequalities in health.

A Mathematical Model Supporting a Hyperpredation Effect in the Apparent Competition Between Invasive Eastern Cottontail and Native European Hare

In this work a mathematical model is built in order to validate on theoretical grounds field study results on a three-species system made of two prey, of which one is native and another one invasive, together with a native predator. Specifically, our results mathematically describe the negative effect on the native European hare after the introduction of the invasive Eastern cottontail, mediated by an increased predation rate by foxes. Two nonexclusive assumptions can be made: an increase in cottontail abundance would lead to a larger fox population, magnifying their predatory impact (“hyperpredation”) on hares; alternatively, cottontails attract foxes in patches where they live, which are also important resting sites for hares and consequently the increased presence of foxes results in a higher predation rates on hares. The model results support hyperpredation of increasing fox populations on native hares.