Developing markets for recyclate: perspectives from south Wales

This paper introduces the problems of a market-driven waste management strategy in the UK and the momentum towards developing markets for recycled materials. It focuses on the demand side barriers and principally the need for market stimulation in the end uses for recyclables. The important role, which small- and medium-sized manufacturing enterprises (SMEs) have to play in developing existing markets for recyclate, is discussed. SMEs also have the potential to contribute to the radical new approach of identifying and developing a broad range of new, more diverse and higher value uses for recyclate. If these enterprises are to be engaged effectively then regional action is essential. The paper then reports on research work focusing on SMEs that has taken place as a component of the CWMRE (Creating Welsh Markets for REcyclate) market development initiative in Wales. As a foundation for this, a series of semi-structured interviews with SMEs has been conducted with those operating in sectors that are known to have the potential to provide novel applications for secondary materials or to have the potential for material displacement. Some of the barriers and corresponding needs within the case study companies involved are discussed. The implications of these findings for a regional market development programme are considered and in particular how these case studies support the need to engage SMEs in the use of secondary materials.     

The influence of nectar secretion rates on the responses of bumblebees (Bombus spp.) to previously visited flowers

Bumblebees can avoid recently depleted flowers by responding to repellent scent-marks deposited on flower corollas by previous visitors. It has previously been suggested that avoidance of visited flowers for a fixed period would be a poor strategy, since different plant species vary greatly in the rate at which they replenish floral rewards. In this study, we examined the duration of flower repellency after an initial bumblebee visit, using wild bumblebees (Bombus lapidarius, B. pascuorum and B. terrestris) foraging on four different plant species (Lotus corniculatus, Melilotus officinalis, Phacelia tanacetifolia and Symphytum officinale). We constructed a model to predict flower visitation following an initial visit, based on the nectar secretion pattern of the different plant species, the insect visitation rate per flower, and the search and handling times of bumblebees foraging on the plant species in question. The model predicts an optimal duration of flower avoidance which maximises the rate of reward acquisition for all bees. However, this optimum may be open to cheating. For two plant species, the evolutionary stable strategy (ESS) is a shorter duration of flower avoidance than the optimum. We found the duration of flower avoidance was markedly different among flower species and was inversely related to nectar secretion rates. The predicted ESSs for each plant species were close to those observed, suggesting that the key parameters influencing bumblebee behaviour are those included in the model. We discuss how bees may alter the duration of their response to repellent scents, and other factors that affect flower re-visitation.     

Multiple mating and facultative polygyny in the Panamanian leafcutter ant Acromyrmex echinatior

Queen mating frequency of the facultatively polygynous ant Acromyrmex echinatior was investigated by analysing genetic variation at an (AG)_n repeat microsatellite locus in workers and sexuals of 20 colonies from a single Panamanian population. Thirteen colonies were found to be monogynous, 5 colonies contained multiple queens, whereas the queen number of 2 colonies remained unresolved. Microsatellite genotypes indicated that 12 out of 13 queens were inseminated by multiple males (polyandry). The mean queen mating frequency was 2.53 and the mean genetically effective paternity frequency was 2.23. These values range among the highest found in ants, and the results are in keeping with the high mating frequencies reported for other species of leafcutter ants. Consistent skew in the proportional representation of different patrilines within colonies was found, and this remained constant in two consecutive samples of offspring. Dissections showed that all examined queens from multiple-queen colonies were mated egg-layers. The mean relatedness value among nestmate workers in polygynous colonies was lower than that for monogynous colonies. No diploid males were detected in a sample of 70 genotyped males. Worker production of males was detected in one queenless colony. We discuss our findings in relation to known patterns of multiple maternity and paternity in other eusocial Hymenoptera. Received: 2 September 1998 / Received in revised form: 3 February 1999 / Accepted: 7 February 1999     

Sex ratios and life-history patterns of a solitary wasp,Trypoxylon (Trypargilum) politum (Hymenoptera : Sphecidae)

Summary Werren and Charnov (1978) and Seger (1983) proposed a model to explain a fairly common pattern of alternating sex ratio biases between generations in partially bivoltine insects. When first-generation males overlap and mate with females of the second generation, then females should bias sex ratios in favor of sons for the first generation and daughters for the second generation. In an intensive, 7-year study at four sites in northern Florida, pipe-organ mud-daubing wasps (Trypoxylon (Trypargilum) politum; Hymenoptera: Sphecidae) were found to have strongly male-biased sex ratios in the first or overwintering generation and 1:1 or female-biased sex ratios in the second or summer generation. These differences were not due to differences in mortality of the two sexes but rather resulted from changing female sex-allocation decisions. In some respects the mud dauber results fit Seger's model well: alternating sex ratios in partially bivoltine populations, first-generation males overlapping second-generation females and perhaps most convincingly, northern, univoltine populations do not have a male bias. Despite this qualitative fit, however, our data do not meet the quantitative predictions of the model. This could result from the fact that some assumptions of the model are not met by the life history of T. politum. Alternative explanations for alternating sex ratios include split sex ratios, seasonal differences in cost ratios, facultative maternal investment rules and facultative overwintering decisions by offspring. Despite the position that sex ratios have achieved in the modern study of evolution, it is clear that accurate, quantitative predictions on sex-allocation patterns demand the same detailed understanding of the biology of the organism that is required for the study of other adaptations.     

Repellent scent-marking of flowers by a guild of foraging bumblebees (Bombus spp.)

We have found that foraging bumblebees (Bombus hortorum, B. pascuorum, B. pratorum and B.␣terrestris) not only avoid flowers of Symphytum officinale that have recently been visited by conspecifics but also those that have been recently visited by heterospecifics. We propose that the decision whether to reject or accept a flower is influenced by a chemical odour that is left on the corolla by a forager, which temporarily repels subsequent foragers. Honeybees and carpenter bees have previously been shown to use similar repellent forage-marking scents. We found that flowers were repellent to other bumblebee foragers for approximately 20 min and also that after this time nectar levels in S. officinale flowers had largely replenished. Thus bumblebees could forage more efficiently by avoiding flowers with low rewards. Flowers to which extracts of tarsal components were applied were more often rejected by wild B. terrestris workers than flowers that had head extracts applied, which in turn were more often rejected than flowers that had body extracts applied. Extracts from four Bombus species were equally repellent to foragers. The sites of production of the repellent scent and its evolutionary origins are discussed. Received: 24 November 1997 / Accepted after revision: 8 March 1998     

Does the risk of encountering lions influence African herbivore behaviour at waterholes?

A central question in the study of predator–prey relationships is to what extent prey behaviour is determined by avoidance of predators. Here, we test whether the long-term risk of encountering lions and the presence of lions in the vicinity influence the behaviour of large African herbivores at waterholes through avoidance of high-risk areas, increases in group size, changes in temporal niche or changes in the time spent in waterhole areas. In Hwange National Park, Zimbabwe, we monitored waterholes to study the behaviour of nine herbivore species under different risks of encountering lions. We radio-collared 26 lions in the study area which provided the opportunity to monitor whether lions were present during observation sessions and to map longer-term seasonal landscapes of risk of encountering lions. Our results show that the preferred prey species for lions (buffalo, kudu and giraffe) avoided risky waterholes. Group size increased as encounter risk increased for only two species (wildebeest and zebra), but this effect was not strong. Interestingly, buffalo avoided the hours of the day which are dangerous when the long-term and short-term risks of encountering lions were high, and all species showed avoidance of waterhole use at night times when lions were in the vicinity. This illustrates well how prey can make temporal adjustments to avoid dangerous periods coinciding with predator hunting. Additionally, many herbivores spent more time accessing water to drink when the long- and short-term risks of encountering lions were high, and they showed longer potential drinking time when the long-term risk of encountering lions was high, suggesting higher levels of vigilance. This study illustrates the diversity of behavioural adjustments to the risk of encountering a predator and how prey respond differently to temporal variations in this risk.     

Rural household vulnerability to climate risk in Uganda

Regional Environmental Change - Vulnerability assessment is fundamental for informing adaptation to climate change policy. The aim of this study is to evaluate the vulnerability of rural...     

Pressure- volume- temperature relationships of soy protein isolate/starch plastic

The use of pressure-volume-temperature (PVT) studies in processing of a biodegradable plastic composition made from soy protein isolate and corn starch is described. The ability of PVT measurements to predict the combined effects of pressure, volume, and temperature effects is demonstrated. The results show that the PVT relations of the plastic can be predicted by using a regression analysis similar to the Tait equations of state. A change in slope of the PVT curves was observed at around 80‡C, which is ascribed to the glass-transition process of the plastic. Evidence of onset of thermal degradation of the plastic was observed at ca. 160‡C under 0 to 200 MPa isobaric pressure. This thermal degradation precluded determination of the crystal melting point of the plastic.     

Anticoagulant rodenticide exposure in raptors from Ontario,Canada

Environmental Science and Pollution Research - Anticoagulant rodenticides (ARs) are used globally to control rodent pest infestations in both urban and agricultural settings. It is well documented...     

Conservation Implications of Introduced Game Birds in High-Elevation Hawaiian Shrubland

The Ring-necked Pheasant ( Phasianus colchicus ) and the Chukar ( Alectoris chukar ) are the dominant avifauna in high-elevation shrubland (2070–3000 m) of Haleakala National Park, Maui, Hawaii. We studied the food habits, ecological niche, and effects of these alien game birds on the native biota in this Hawaiian ecosystem. Analyses of crop contents indicated that pheasant and Chukar consumed predominantly fruits of native, woody dicots (39% and 47% respectively) and leaves (29% and 24% respectively) and flower parts (12% and 17% respectively) of alien, herbaceous dicots. Both species generally selected food items according to their relative availability, although other factors influenced choice of certain items. Invertebrates were a minor component of the game-bird diet, suggesting that their impact on native invertebrate populations is minimal. Pheasant and Chukar occupy, at least partially, an ecological niche once held by now-extinct or rare birds, and they appear not to be significant competitors with the endangered Nene. The role of these alien birds in facilitating seed dispersal and germination of native plant species is beneficial in restoring degraded ecosystems.