Similarity at the major histocompatibility complex class II does not influence mating patterns in bluegill (Lepomis macrochirus)

Behavioral Ecology and Sociobiology - Consistent between-individual differences in behaviour, known as personality differences, are heritable and have consequences for individual survival and...     

The multifunctionality of urban farming: perceived benefits for neighbourhood improvement

Urban farming – a type of urban agriculture focused on entrepreneurial food production – serves multiple functions in neighbourhoods; yet these are not well delineated. Expectations for urban farming often centre on traditional measures of economic development, potentially overlooking other benefits. Through a qualitative case study conducted in Baltimore, Maryland, we sought to understand community perceptions regarding the ways in which urban farms can benefit cities. Interviews with residents, neighbourhood leaders, and urban farmers in three residential neighbourhoods with urban farms revealed the pathways by which community members view farms as improving neighbourhoods. Benefits stemmed from four primary changes urban farms made to study neighbourhoods: creation of public projects welcoming involvement, physical improvement of degraded space, production of local food, and creation of new businesses. These changes led to multiple perceived benefits including increased social connectedness, a transformed physical landscape, improved neighbourhood reputation, increased access to fresh produce, and educational, youth development, and employment opportunities. Our findings demonstrate the importance of a multifunctional paradigm that accounts for social and educational functions in assessing the value of urban farming and bring empirical evidence to the concept of multifunctional agriculture. Urban farms with strong social aims may appear to contribute little to economic development if measured using traditional indicators of success such as job creation or fiscal impacts, but provide numerous other benefits for community development.     

Solitary nesting as an alternative breeding tactic in colonial nesting bluegill sunfish (Lepomis macrochirus)

Colonial breeding can evolve in response to benefits afforded by clumped individuals, such as reduced predation and increased ease of assessing potential mates. However, colonial breeding can also impose costs such as increased disease transmission or increased cuckoldry. Here, we investigate solitary nesting as a potential alternative breeding tactic in colonial breeding bluegill sunfish (Lepomis macrochirus). Most male bluegill, termed parentals, compete for nesting sites in colonies and then court and spawn with females and provide sole care of the eggs. Although nesting in a colony results in reduced predation and fungal infection of broods, it comes at a cost of increased parasitism by specialized cuckolder males that do not nest. We found that 4.5% of parentals forgo spawning in a colony and instead construct nests solitarily. Solitary males were of similar size and age to colonial males, but were in significantly better condition. Solitary males obtained as many eggs as males nesting in the center of colonies, and significantly more than males nesting on the periphery of colonies. Thus, females do not appear to discriminate against solitary males. Solitary males had smaller ear tabs, a presumed sexually selected character used by parental males in intrasexual competition, than colonial males. Tracking data revealed consistency in nesting tactic (but not nest position within the colony) between spawning attempts. We suggest that solitary nesting represents either a facultative decision made by parental males in top condition at the onset of breeding, or a life history decision to forgo spawning in colonies.Communicated by K. Lindström     

Development of a risk assessment methodology for evaluating potential impacts associated with contaminated mud disposal in the marine environment

In order to assess impacts associated with disposal of contaminated mud arising from Hong Kong's dredging and reclamation projects, a methodology has been formulated to determine the level of risk posed by consumption of seafood/marine prey species to humans and to the Chinese White Dolphin (Sousa chinensis). This methodology improves on previously used techniques by incorporating risks for organic contaminants, accounting for doses from sources other than seafood, and incorporating additional local knowledge on Sousa chinensis behaviour. It thus represents an advance in risk assessment techniques and a new integration of risk assessment and monitoring in environmental management.     

SATELLITE MICROWAVE OBSERVATIONS OF SOIL MOISTURE VARIATIONS1

ABSTRACT: Results from studies in the Illinois-Indiana and Texas-Oklahoma areas indicate that satellite microwave observations at the 1.55 cm wavelength are responsive to relative moisture variations in the near surface layer of the soil. Because significant vegetation cover absorbs the 1.55 cm microwave emission from the soil, the target area must be predominately bare soil or low density vegetation cover for meaningful measurements to result. The 25 km resolution of the satellite sensor limits application of the microwave techniques to large areas such as watersheds or agricultural districts rather than individual fields. In general, at 1.55 cm. there is an inverse relationship between microwave brightness temperature and changes in soil moisture levels (as indicated by antecedent rainfall) in agricultural regions before the planting of crops or during the early growing season when vegetation cover is sparse. Even early season observations should be of great value in deciding on the time and type of crop planting and for initial irrigation scheduling when the root zone is still in close proximity to the surface.     

Modeling Connectivity of Non‐floodplain Wetlands: Insights,Approaches, and Recommendations

Representing hydrologic connectivity of non‐floodplain wetlands (NFWs) to downstream waters in process‐based models is an emerging challenge relevant to many research, regulatory, and management activities. We review four case studies that utilize process‐based models developed to simulate NFW hydrology. Models range from a simple, lumped parameter model to a highly complex, fully distributed model. Across case studies, we highlight appropriate application of each model, emphasizing spatial scale, computational demands, process representation, and model limitations. We end with a synthesis of recommended “best modeling practices” to guide model application. These recommendations include: (1) clearly articulate modeling objectives, and revisit and adjust those objectives regularly; (2) develop a conceptualization of NFW connectivity using qualitative observations, empirical data, and process‐based modeling; (3) select a model to represent NFW connectivity by balancing both modeling objectives and available resources; (4) use innovative techniques and data sources to validate and calibrate NFW connectivity simulations; and (5) clearly articulate the limits of the resulting NFW connectivity representation. Our review and synthesis of these case studies highlights modeling approaches that incorporate NFW connectivity, demonstrates tradeoffs in model selection, and ultimately provides actionable guidance for future model application and development.     

Male size and mating tactic influence proximity to females during sperm competition in bluegill sunfish

Many fishes are characterized by intense sperm competition between males that use alternative mating tactics. In externally fertilizing fishes, males’ proximity to females during spawning can be an important determinant of fertilization success. Here, we assess how mating tactic, body length, speed during streak spawns, and periphery cover affect males’ proximity to females during sperm competition in the externally fertilizing bluegill (Lepomis macrochirus). Bluegill are characterized by three mating tactics referred to as parental, sneaker, and satellite. Parentals are territorial and construct nests, while sneakers use a streaking behavior, and satellites use female mimicry to steal fertilizations from parentals. We show that a small body length is important for sneakers but not for satellites to obtain a close position to the female during spawning. Specifically, smaller sneakers obtain a closer position to females than larger sneakers in part by positioning themselves closer on the periphery of a parental’s nest before streaking but show no difference in the speed at which they streak. The amount of peripheral vegetation around a parental’s nest did not appear to affect proximity of sneakers to females, and there was no relationship between the amount of peripheral vegetation and the frequency of intrusions by either sneakers or satellites. Finally, parentals were farther from the female when a sneaker or satellite intruded than when they spawned alone with the female.     

Accumulation and release of petroleum-derived aromatic hydrocarbons by four species of marine animals

Survival of Ctenodiscus crispatus during exposure to hypoxia (P _{O 2}<3 mm Hg) at 5°C is greater than that of any echinoderm reported in the literature, the LT₅₀ being 248 h; this is reduced to 236 h in the presence of hydrogen sulfide. Unlike Asterias vulgaris and A. forbesi, both of which lose the tube foot response to tactile stimulation long before death from hypoxia occurs, C. crispatus remains responsive until death. The extension of the highly protrusible epiproctal cone, which occurs in 75% of the mud stars simultaneously exposed to hypoxia and H₂S, serves to maintain burrow contact with the overlying water. The rate of oxygen consumption remains constant down to an ambient oxygen partial pressure of 10 to 25 mm Hg, becoming more oxygen-dependent after prior exposure of the asteroids to hypoxia. C. crispatus exhibits a clear oxygen-debt phenomenon as well as a compensatory reduction in the residual P _{O 2} (oxygen partial pressure at which oxygen consumption ceases) from 2.4 to 0.2 mm Hg after hypoxic exposure.     

Toxic Effect of a Pesticide, Diflubenzuron on Freshwater Microinvertebrate (Tetrahymena pyriformis)

Harmful bugs affect food production,directly by the qualitativeor quantitative reduction of the harvests,or indirectly while servinglike vectors of several illnesses of the plants and human[1].Many chemical products are used by human for a long time inthe…     

No Meat,Less Meat,or Better Meat: Understanding NGO Messaging Choices Intended to Alter Meat Consumption in Light of Climate Change

This paper examines the factors shaping non-governmental organization (NGO) messaging decisions on how meat consumption should be altered in light of climate change. In particular, we sought to understand the relative absence of messages promoting meat-free diets and the decision of some NGOs to pair meat reduction messages with messages encouraging consumers to switch to meat from ruminant grass-fed animals. Interviews were conducted with 27 staff members from environmental, food-focused, and animal protection NGOs from the USA, Canada, and Sweden. While strategic considerations consistently led to the use of modest messages for meat reduction, NGO missions were also key to shaping the specifics of messaging goals. The relatively low personal comfort levels that some NGO staffers held toward meat-free diets also led to the use of more modest requests for meat reduction. Findings highlight the complex nature of the factors underlying the environmental communication messages of NGOs.