Nest ectoparasites increase physiological stress in breeding birds: an experiment

Parasites are undoubtedly a biotic factor that produces stress. Heat shock proteins (HSPs) are important molecules buffering cellular damage under adverse conditions. During the breeding season, blue tit Cyanistes caeruleus (L.) adults are affected by blood parasites, nest-dwelling parasites and biting flies, potentially affecting their HSP-mediated responses. Here, we treated females with primaquine to reduce blood parasites and fumigated nests with permethrin to reduce nest-dwelling parasites to test whether these treatments affect HSP60 level during the breeding season. Medicated females, but not controls, had a significant reduction of the intensity of infection by Haemoproteus spp. blood parasites. However, final intensity of infection did not differ significantly between groups, and we did not find an effect of medication on change in HSP60 level. Fumigation reduced the abundance of nest-dwelling parasites (mites, fleas and blowfly larvae) and engorged biting midges in nests. Females breeding in non-fumigated nests increased HSP60 levels during the season more than those breeding in fumigated nests. Furthermore, the change in HSP60 level was positively correlated with the abundance of biting midges. These results show how infections by nest ectoparasites during the breeding period can increase the level of HSPs and suggest that biting midges impose physiological costs on breeding female blue tits. Although plausible, the alternative that biting midges prefer to feed on more stressed birds is poorly supported by previous studies.     

Comparison of 226Ra nuclide from soil by three woody species Betula pendula, Sambucus nigra and Alnus glutinosa during the vegetation period

The uptake of 226Ra from the contaminated soil was compared in three woody species: alder (Alnus glutinosa), birch (Betula pendula) and elder (Sambucus nigra). The 226Ra activities increased during the vegetation periods (in 2003, 2004 and 2005) both in the leaves and flowers+seeds. The highest accumulation was found in birch, reaching 0.41 Bq/g DW in the leaves (at the end of the vegetation period in 2003). The lowest 226Ra accumulation was determined in alder. The extent of 226Ra accumulation in the leaves of woody species demonstrates that these pioneer woody species can be used as remediation alternative to the use of herbs, provided that the removal of fallen leaves could be achieved in the end of vegetation period.     

Survival of Human Adenovirus 41 in Land-Applied Manure and Biosolids

Human Adenovirus 41 (Ad41) is an important human enteric pathogen and widely prevalent in the environment. The aim of this study was to assess the survival of Ad41 based on genome stability and infectivity in different types of manure and three types of biosolids. For viral survival studies, Ad41 was added to pelletized poultry litter (PL), alum-treated poultry litter (AL), raw poultry litter (RPL), liquid dairy manure (DM), swine manure (SM), and three types of biosolids 1, 2, 3. All samples were stored at 20 or 4°C and analyzed every 10 days for up to 60 days. Quantification PCR (qPCR) standard curves were generated for PL, AL, biosolids 1, and DM to measure the number of viral genomic copies remaining in the samples. To study the infectivity, all contaminated manure/biosolids samples were added to mammalian cell culture and viral mRNA was detected using one-step RT–PCR. Overall, Ad41 viral genomes were stable at both 20 and 4°C and there was no significant loss of viral DNA after 60 days in PL, AL, biosolids type 1, and DM. However, infectivity was lost almost immediately in high pH biosolids type 2 and 3, and infectivity decreased quickly in DM, with estimated T90 of 4.3 and 8.7 days at 20 and 4°C, respectively. Ad41 had ~1.9 log loss of infectivity after added in SM and biosolids type 1 at day 0, and estimated T90 was 12.5 and 28.6 days for biosolids type 1, and 19.1 and 51.0 days for SM at 20 and 4°C, respectively. Ad41 maintained infectivity in all three poultry litter, and after 60 days incubation, there were significantly more infectious virus in PL, AL, and RPL than biosolids 1, SM, and DM at 20°C.     

Varying levels of female promiscuity in four <Emphasis Type="Italic">Apodemus</Emphasis> mice species

Sexual selection in most vertebrates is based on the evolution of fitness optimization strategies such as multiple-male mating (MMM). Several ecological correlates of MMM have been identified in bird and fish populations; however, only few studies have documented the effects of environmental change on promiscuity in mammals. In this study, the 127 pregnant females from four central European and ecologically diverse species of field mice (genus Apodemus) were studied to assess the role of ecological factors that may have shaped the evolution of particular mating systems. MMM was found in all analyzed species: in Apodemus uralensis and Apodemus flavicollis, up to two males could be identified as the fathers of a particular litter, while three males sired 9.1% of analyzed litters of Apodemus sylvaticus and 20.6% of Apodemus agrarius. Furthermore, there were obvious differences between species in relative testes size and the proportion of multiple sired litters during those seasons when the opportunity for multiple mating was high. The species with the smallest testes and the least promiscuous was A. uralensis (only 43.5% of multiple sired litters), while the species with the biggest testes and the most promiscuous was A. agrarius (69.2%). MMM was significantly associated with higher litter size in A. flavicollis, and the probability of MMM strongly increased with season in A. agrarius and with abundance in A. uralensis. These results indicate that ecological factors are associated with MMM rates in Apodemus field mice and more research is needed to fully understand the evolution of mating strategies at different levels of biological resolution.     

Recruitment and ontogenetic habitat shifts of the yellow snapper (<Emphasis Type="Italic">Lutjanus argentiventris</Emphasis>) in the Gulf of California

We examined recruitment and ontogenetic habitat shifts of the yellow snapper Lutjanus argentiventris in the Gulf of California, by conducting surveys and collections in multiple mangrove sites and major marine coastal habitats from 1998 to 2007. Over 1,167 juvenile individuals were collected and 516 otoliths were aged to describe the temporal pattern of the settlement. L. argentiventris recruits in mangroves, where juveniles remain until they are approximately 100 mm in length or 300-days-old. Back-calculated settlement dates and underwater surveys indicated a major recruitment peak during September and October, around 8 days before and after the full moon. The majority of mangrove sites in the Gulf of California had a similar L. argentiventris average size at the beginning of the settlement season for the cohort of 2003; although there were significant differences in individual sizes at the end of the nursery stage. When sub-adults leave mangroves, they live in shallow rocky reefs and later become abundant in deeper rocky reefs. The density of migratory individuals (10–20 cm SL) decreased exponentially as the distance between a reef and a nearby mangrove site increased. This finding has important implications for local fishery regulations and coastal management plans.     

Using social network analysis tools in ecology: Markov process transition models applied to the seasonal trophic network dynamics of the Chesapeake Bay

Ecosystem components interact in complex ways and change over time due to a variety of both internal and external influences (climate change, season cycles, human impacts). Such processes need to be modeled dynamically using appropriate statistical methods for assessing change in network structure. Here we use visualizations and statistical models of network dynamics to understand seasonal changes in the trophic network model described by Baird and Ulanowicz [Baird, D., Ulanowicz, R.E., 1989. Seasonal dynamics of the Chesapeake Bay ecosystem. Ecol. Monogr. 501 (59), 329–364] for the Chesapeake Bay (USA). Visualizations of carbon flow networks were created for each season by using a network graphic analysis tool (NETDRAW). The structural relations of the pelagic and benthic compartments (nodes) in each seasonal network were displayed in a two-dimensional space using spring-embedder analyses with nodes color-coded for habitat associations (benthic or pelagic). The most complex network was summer, when pelagic species such as sea nettles, larval fishes, and carnivorous fishes immigrate into Chesapeake Bay and consume prey largely from the plankton and to some extent the benthos. Winter was the simplest of the seasonal networks, and exhibited the highest ascendency, with fewest nodes present and with most of the flows shifting to the benthic bacteria and sediment POC compartments. This shift in system complexity corresponds with a shift from a pelagic- to benthic-dominated system over the seasonal cycle, suggesting that winter is a mostly closed system, relying on internal cycling rather than external input. Network visualization tools are useful in assessing temporal and spatial changes in food web networks, which can be explored for patterns that can be tested using statistical approaches. A simulation-based continuous-time Markov Chain model called SIENA was used to determine the dynamic structural changes in the trophic network across phases of the annual cycle in a statistical as opposed to a visual assessment. There was a significant decrease in outdegree (prey nodes with reduced link density) and an increase in the number of transitive triples (a triad in which i chooses j and h, and j also chooses h, mostly connected via the non-living detritus nodes in position i), suggesting the Chesapeake Bay is a simpler, but structurally more efficient, ecosystem in the winter than in the summer. As in the visual analysis, this shift in system complexity corresponds with a shift from a pelagic to a more benthic-dominated system from summer to winter. Both the SIENA model and the visualization in NETDRAW support the conclusions of Baird and Ulanowicz [Baird, D., Ulanowicz, R.E., 1989. Seasonal dynamics of the Chesapeake Bay ecosystem. Ecol. Monogr. 501 (59), 329–364] that there was an increase in the Chesapeake Bay ecosystem's ascendancy in the winter. We explain such reduced complexity in winter as a system response to lowered temperature and decreased solar energy input, which causes a decline in the production of new carbon, forcing nodes to go extinct; this causes a change in the structure of the system, making it simpler and more efficient than in summer. It appears that the seasonal dynamics of the trophic structure of Chesapeake Bay can be modeled effectively using the SIENA statistical model for network change.     

Repeatability and heritability of sperm competition outcomes in males and females of <Emphasis Type="Italic">Tribolium castaneum</Emphasis>

Differences among males in their success in achieving fertilisations when females mate with more than one partner are now recognised as an important target of sexual selection. However, very few studies have attempted to determine whether particular males are consistently successful in sperm competition and whether success in sperm competition is a heritable trait. Additionally, the potential heritability of female traits that influence the outcome of sperm competition has received only limited attention. Using the polyandrous beetle Tribolium castaneum, we examined repeatability of male success in sperm competition by mating pairs of males carrying different visible genetic markers to a string of different females. Males showed consistency in their ability to successfully transfer sperm to females, but not in their success in sperm competition. Furthermore, when we independently compared success in sperm competition of fathers with their sons, we found no evidence for heritability of this trait. Similarly, females that exhibited high or low first male sperm precedence did not tend to have daughters that showed the same pattern. Our results suggest that we should be wary of assuming that success in sperm competition is heritable through either sex.     

The United States Environmental Protection Agency's Role in Controlling Aquatic Debris

Unsightly and environmentally damaging debris is an ever present problem for waterways and beaches around the world. This debris has numerous sources, and is comprised of materials ranging from metal and wood to plastics and paper. the aesthetic, economic, and environmental impacts of debris have been well documented over the past several years. in an effort to control the release of trash and debris into our waters, there are many activities ongoing in the US. One such activity is a coordinated effort between the US Environmental Protection Agency (EPA), other federal Agencies (National Oceanic and Atmospheric Administration (NOAA), United States Coast Guard (USCG), United States Navy (USN), National Park Service (NPS), Department of Interior (DOI)), industry (the Society of the Plastics Industry, INC. (SPI)), environmental, and local groups. This paper describes the results of field assessments, and the other activities undertaken by EPA as part of this coordinated effort to control the release of debris to our nation's waterways.     

Great spotted cuckoo fledglings are disadvantaged by magpie host parents when reared together with magpie nestlings

The post-fledging period is a critical phase for juvenile survival, and parental care provided during this period is a key component of avian reproductive performance. Very little is known about the relationships between foster parents and fledglings of brood parasites. Here, we present the results of a 5-year study about the relationships between fledglings of the non-evictor brood parasitic great spotted cuckoo (Clamator glandarius) and its magpie (Pica pica) foster parents. Sometimes, great spotted cuckoo and magpie nestlings from the same nest can fledge successfully, but most often parasitic nestlings outcompete host nestlings and only cuckoos leave the nest. We have studied several aspects of cuckoo post-fledging performance (i.e. feeding behaviour, parental defence and fledgling survival) in experimental nests in which only cuckoos or both magpie and cuckoo nestlings survived until leaving the nest. The results indicate that great spotted cuckoo fledglings reared in mixed broods together with magpie nestlings were disadvantaged by magpie adults with respect to feeding patterns. Fledgling cuckoos reared in mixed broods were fed less frequently than those reared in only cuckoo broods, and magpie adults approached less frequently to feed cuckoos from mixed broods than cuckoos from only cuckoo broods. These results imply that the presence of host's own nestlings for comparison may be a crucial clue favouring the evolution of fledgling discrimination; and furthermore, that the risk of discrimination at the fledgling stage probably is an important selection pressure driving the evolution of the arms race between brood parasites and their hosts.