To females of a noctuid moth,male courtship songs are nothing more than bat echolocation calls

It has been proposed that intraspecific ultrasonic communication observed in some moths evolved, through sexual selection, subsequent to the development of ears sensitive to echolocation calls of insectivorous bats. Given this scenario, the receiver bias model of signal evolution argues that acoustic communication in moths should have evolved through the exploitation of receivers'' sensory bias towards bat ultrasound. We tested this model using a noctuid moth Spodoptera litura, males of which were recently found to produce courtship ultrasound. We first investigated the mechanism of sound production in the male moth, and subsequently the role of the sound with reference to the female''s ability to discriminate male courtship songs from bat calls. We found that males have sex-specific tymbals for ultrasound emission, and that the broadcast of either male songs or simulated bat calls equally increased the acceptance of muted males by the female. It was concluded that females of this moth do not distinguish between male songs and bat calls, supporting the idea that acoustic communication in this moth evolved through a sensory exploitation process.     

Investigating cat predation as the cause of bat wing tears using forensic DNA analysis

Cat predation upon bat species has been reported to have significant effects on bat populations in both rural and urban areas. The majority of research in this area has focussed on observational data from bat rehabilitators documenting injuries, and cat owners, when domestic cats present prey. However, this has the potential to underestimate the number of bats killed or injured by cats. Here, we use forensic DNA analysis techniques to analyze swabs taken from injured bats in the United Kingdom, mainly including Pipistrellus pipistrellus (40 out of 72 specimens). Using quantitative PCR, cat DNA was found in two‐thirds of samples submitted by bat rehabilitators. Of these samples, short tandem repeat analysis produced partial DNA profiles for approximately one‐third of samples, which could be used to link predation events to individual cats. The use of genetic analysis can complement observational data and potentially provide additional information to give a more accurate estimation of cat predation.     

Foraging patterns of voles at heterogeneous avian and uniform mustelid predation risk

Temporal variation of antipredatory behavior and a uniform distribution of predation risk over refuges and foraging sites may create foraging patterns different from those anticipated from risk in heterogenous habitats. We studied the temporal variation in foraging behavior of voles exposed to uniform mustelid predation risk and heterogeneous avian predation risk of different levels induced by vegetation types in eight outdoor enclosures (0.25 ha). We manipulated mustelid predation risk with weasel presence or absence and avian predation risk by reducing or providing local cover at experimental food patches. Foraging at food patches was monitored by collecting giving-up densities at artificial food patches, overall activity was automatically monitored, and mortality of voles was monitored by live-trapping and radiotracking. Voles depleted the food to lower levels in the sheltered patches than in the exposed ones. In enclosures with higher avian predation risk caused by lower vegetation height, trays were depleted to lower levels. Unexpectedly, voles foraged in more trays and depleted trays to lower levels in the presence of weasels than in the absence. Weasels match their prey's body size and locomotive abilities and therefore increase predation risk uniformly over both foraging sites and refuge sites that can both be entered by the predator. This reduces the costs of missing opportunities other than foraging. Voles changed their foraging strategy accordingly by specializing on the experimental food patches with predictable returns and probably reduced their foraging in the matrix of natural food source with unpredictable returns and high risk to encounter the weasel. Moreover, after 1 day of weasel presence, voles shifted their main foraging activities to avoid the diurnal weasel. This behavior facilitated bird predation, probably by nocturnal owls, and more voles were killed by birds than by weasels. Food patch use of voles in weasel enclosures increased with time. Voles had to balance the previously missed feeding opportunities by progressively concentrating on artificial food patches.     

Absence from the nest due to human disturbance induces higher nest predation risk than natural recesses in Common Eiders Somateria mollissima

Human disturbance of nesting birds may cause reduced breeding success. It is therefore necessary to assess the impact of disturbance to identify steps that minimize negative impacts. We carried out a study of nesting success at two adjacent colonies of Common Eider Somateria mollissima on the islands of Grindøya and Håkøya in northern Norway between 2006 and 2011. Over the study period, nesting success was consistently higher on Håkøya (69–82%) than on Grindøya (35–60%). Between 2009 and 2011 we used camera monitoring of individual nests to identify determinants of nest survival and predation, focusing in particular on the effect of departures from the nest due to human disturbance, which differed between the colonies due to a long‐term research project on Grindøya. Overall, absence of Common Eiders from nests due to disturbance increased the predation risk by a factor of 6.42 for an increase of one additional daily disturbance. In contrast, absence due to natural recesses did not increase nest losses. Under high levels of human disturbance, camera monitoring indicated that the main cause of breeding failure was predation, primarily by Hooded Crows Corvus cornix, but also to some extent Great Black‐backed Gulls Larus marinus. The presence of cameras did not increase the predation risk. Both the presence of researchers and the sight of Common Eider females conspicuously departing from nests are likely to have provided cues to these predators. We suggest management trials to reduce nesting disturbance through the guarding of unoccupied nests to mitigate the effects of human disturbance on reproductive success.     

Methoprene-induced matings of young Queensland fruit fly males are effective at inducing sexual inhibition in females

Pre-release dietary treatment with methoprene, a juvenile hormone analogue, decreases the age at which male Queensland fruit flies mature and hence may decrease the post-release delay until released sterile flies participate in sterile insect technique (SIT) programmes. However, if matings of young methoprene-treated males are not effective at inducing sexual inhibition in their mates, then this treatment may not enhance SIT. The present study investigates efficacy of matings of methoprene-treated males at inducing sexual inhibition in their mates. Methoprene incorporated into a diet of sugar and yeast hydrolysate (w/w 3:1) for 48 hr after emergence resulted in significantly increased male mating propensity when flies were <10 days of age, but not when older, and longer copulations. Copula latency did not vary with methoprene treatment but did decrease with age. The matings of young methoprene-treated males were effective at inducing sexual inhibition in their mates, matching the efficacy of untreated mature males. Regardless of treatment, females had reduced tendency to remate if their first mate was 15 days of age than if their first mate was younger (6, 8 days) or older (20, 25, 30 days). Females mated by methoprene-treated males that did remate tended to remate later in the day than females mated by untreated males. Also, second copula durations of females first mated by a 6- to 10-day-old male were shorter if the male was methoprene treated. These patterns in remating females may indicate greater efficacy of the initial mating of methoprene-treated males. Overall, we find that the additional matings of young methoprene-treated male Queensland fruit flies are effective at inducing sexual inhibition in their mates. This finding supports the incorporation of methoprene into pre-release diet for SIT.     

Children who acquire HIV infection perinatally are at higher risk of early death than those acquiring infection through breastmilk: a meta-analysis

BACKGROUND: Assumptions about survival of HIV-infected children in Africa without antiretroviral therapy need to be updated to inform ongoing UNAIDS modelling of paediatric HIV epidemics among children. Improved estimates of infant survival by timing of HIV-infection (perinatally or postnatally) are thus needed. METHODOLOGY/PRINCIPAL FINDINGS: A pooled analysis was conducted of individual data of all available intervention cohorts and randomized trials on prevention of HIV mother-to-child transmission in Africa. Studies were right-censored at the time of infant antiretroviral initiation. Overall mortality rate per 1000 child-years of follow-up was calculated by selected maternal and infant characteristics. The Kaplan-Meier method was used to estimate survival curves by child's HIV infection status and timing of HIV infection. Individual data from 12 studies were pooled, with 12,112 children of HIV-infected women. Mortality rates per 1,000 child-years follow-up were 39.3 and 381.6 for HIV-uninfected and infected children respectively. One year after acquisition of HIV infection, an estimated 26% postnatally and 52% perinatally infected children would have died; and 4% uninfected children by age 1 year. Mortality was independently associated with maternal death (adjusted hazard ratio 2.2, 95%CI 1.6-3.0), maternal CD4<350 cells/ml (1.4, 1.1-1.7), postnatal (3.1, 2.1-4.1) or peri-partum HIV-infection (12.4, 10.1-15.3). CONCLUSIONS/RESULTS: These results update previous work and inform future UNAIDS modelling by providing survival estimates for HIV-infected untreated African children by timing of infection. We highlight the urgent need for the prevention of peri-partum and postnatal transmission and timely assessment of HIV infection in infants to initiate antiretroviral care and support for HIV-infected children.     

Food quality and quantity are more important in explaining foraging of an intermediate‐sized mammalian herbivore than predation risk or competition

During times of high activity by predators and competitors, herbivores may be forced to forage in patches of low‐quality food. However, the relative importance in determining where and what herbivores forage still remains unclear, especially for small‐ and intermediate‐sized herbivores. Our objective was to test the relative importance of predator and competitor activity, and forage quality and quantity on the proportion of time spent in a vegetation type and the proportion of time spent foraging by the intermediate‐sized herbivore European hare (Lepus europaeus). We studied red fox (Vulpes vulpes) as a predator species and European rabbit (Oryctolagus cuniculus) as a competitor. We investigated the time spent at a location and foraging time of hare using GPS with accelerometers. Forage quality and quantity were analyzed based on hand‐plucked samples of a selection of the locally most important plant species in the diet of hare. Predator activity and competitor activity were investigated using a network of camera traps. Hares spent a higher proportion of time in vegetation types that contained a higher percentage of fibers (i.e., NDF). Besides, hares spent a higher proportion of time in vegetation types that contained relatively low food quantity and quality of forage (i.e., high percentage of fibers) during days that foxes (Vulpes vulpes) were more active. Also during days that rabbits (Oryctolagus cuniculus) were more active, hares spent a higher proportion of time foraging in vegetation types that contained a relatively low quality of forage. Although predation risk affected space use and foraging behavior, and competition affected foraging behavior, our study shows that food quality and quantity more strongly affected space use and foraging behavior than predation risk or competition. It seems that we need to reconsider the relative importance of the landscape of food in a world of fear and competition.     

PVC nest boxes are less at risk of occupancy by feral honey bees than timber nest boxes and natural hollows

Feral European Honey Bee (Apis mellifera) has been identified as a potential nest competitor for Australian hollow nesting species, but few studies have investigated the impact of feral honey bee competition on Threatened species. Our study used data from Glossy Black‐cockatoo (Calyptorhynchus lathami halmaturinus) nests on Kangaroo Island, monitored and managed over an 11‐year period, and found 12% of nests became occupied by feral honey bees during that period. Our results indicate that feral honey bees were less likely to occupy nest boxes made of PVC (5%) compared with wooden nest boxes (24%) or natural hollows in Eucalyptus trees (14%). The removal of feral honey bee hives from nests is a priority for long‐term conservation of glossy black‐cockatoos on Kangaroo Island. We recommend that PVC nest boxes are chosen for future nesting habitat restoration, due to the more frequent use of wooden nest boxes by feral honey bees.