Larval growth rates of the blowfly, Calliphora vicina, over a range of temperatures.

Blowfly larvae (Diptera: Calliphoridae) fulfil an important ecological function in the decomposition of animal remains. They are also used extensively in forensic entomology, predominantly to establish a minimum time since death, or a minimum post-mortem interval, using the larval length as a 'biological clock'. This study examined the larval growth rate of a forensically important fly species, Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae) at temperatures of between 4 degrees C and 30 degrees C, under controlled laboratory conditions. The laboratory flies had been trapped initially in London, U.K. The minimum developmental temperature was estimated to be 1 degrees C and 4700 accumulated degree hours (ADH) were required for development from egg hatch to the point of pupariation. Lines fitted to the laboratory larval growth data were found to adequately explain the growth of larvae in the field. The nature of variation in growth rates from geographically isolated populations is discussed.

Spatial and temporal variability of necrophagous Diptera from urban to rural areas.

The spatio-temporal variability of necrophagous fly assemblages in a linear series of habitats from central London to the rural surroundings in the south-west was studied using bottle traps between June 2001 and September 2002. A total of 3,314 individuals in 20 dipteran families were identified from 127 sampling occasions. Calliphoridae accounted for 78.6% of all the dipteran specimens, with Calliphora vicina Robineau-Desvoidy, being the most abundant species (2,603 individuals, 46.9%). Using canonical correspondence analyses (CCA) on 72 fly taxa, six sampled sites and 36 environmental variables, three habitat types corresponding to three groups of flies were identified. These were an urban habitat characterized by C. vicina, Lucilia illustris (Meigen) and L. sericata (Meigen), a rural grassland habitat, characterized by L. caesar (Linnaeus) and a rural woodland habitat characterized by Calliphora vomitoria (Linnaeus), Phaonia subventa (Harris), Neuroctena anilis (Fallén) and Tephrochlamys flavipes (Zetterstedt). Intermediate species (L. ampullacea Villeneuve and P. pallida (Fabricius), located between the three habitats, were also found. Temporal abundance of the 10 most abundant species showed fluctuations between seasons, having low numbers of captured individuals during winter. Correspondence analysis showed clearly seasonal patterns at Box Hill site. The species-habitat associations suggest habitat differentiation between necrophagous guilds in this area and may be of ecological value.

Compression arthrodesis of the thumb.

A retrospective study of all patients who had undergone thumb arthrodeses at the Denver Orthopedic Clinic since 1972 was undertaken to determine the incidence of satisfactory results with the Micks External Compression Fixator. Sixty-six patients underwent 82 metacarpophalangeal or interphalangeal arthrodeses that resulted in bony fusion in 81 cases. Indications for surgery included pain, instability, and collapse-type thumb deformity. Complications in the 81 successful cases included three that required a second procedure, one for nonunion and two for loss of position. There were eight cases of pin track drainage that cleared with removal of the device and did not adversely influence the outcome. Joints arthrodesed with external compression formed bony union in approximately half the time required for bony unions with Kirschner wire fixation. The fused position of either metacarpophalangeal or interphalangeal joints did not influence patient satisfaction, and all patients were satisfied with their surgery and demonstrated satisfactory use of the thumb.

Energy flow in arboreal epiphytic communities : An empirical model of net primary productivity in the alga Pleurococcus on larch trees.

Energy enters the arboreal epiphytic ecosystem by a number of different pathways. Primary producers such as algae and lichens, together with fungal and bark materials derived in the main from the tree substrate, form the major food components for populations of epiphytic grazing herbivores, notably psocids and collembolans.This paper describes a series of experiments to determine empirically the combined influence of three climatic variables, temperature, light and relative humidity, on the uptake of 14CO2 by the main epiphytic alga, Pleurococcus. A model is produced which indicates that relative humidity is the most important of the variables, followed by light. Temperature appears to be relatively unimportant.The model is discussed with respect to its realism, its predictive powers and its relationship to published data on forest productivity and grazing pressure by psocids.