What does optimization theory actually predict about crown profiles of photosynthetic capacity when models incorporate greater realism?

Measured profiles of photosynthetic capacity in plant crowns typically do not match those of average irradiance: the ratio of capacity to irradiance decreases as irradiance increases. This differs from optimal profiles inferred from simple models. To determine whether this could be explained by omission of physiological or physical details from such models, we performed a series of thought experiments using a new model that included more realism than previous models. We used ray‐tracing to simulate irradiance for 8000 leaves in a horizontally uniform canopy. For a subsample of 500 leaves, we simultaneously optimized both nitrogen allocation (among pools representing carboxylation, electron transport and light capture) and stomatal conductance using a transdermally explicit photosynthesis model. Few model features caused the capacity/irradiance ratio to vary systematically with irradiance. However, when leaf absorptance varied as needed to optimize distribution of light‐capture N, the capacity/irradiance ratio increased up through the crown – that is, opposite to the observed pattern. This tendency was counteracted by constraints on stomatal or mesophyll conductance, which caused chloroplastic CO₂ concentration to decline systematically with increasing irradiance. Our results suggest that height‐related constraints on stomatal conductance can help to reconcile observations with the hypothesis that photosynthetic N is allocated optimally.     

Revision and phylogeny of Syrphetodes (Coleoptera: Ulodidae): implications for biogeography,alpinization and conservation

The genus Syrphetodes Broun is revised to include a total of 13 species. Most of the species are restricted in their distributions, are rarely collected and have been attributed conservation status in New Zealand. Eleven species are described as new: three from Northland (S. relictus sp.n ., Te Paki; S. insularis sp.n. , Three Kings Islands; S. magnus sp.n. , Hokianga), one from the central North Island (S. obtusus sp.n. ), one from Central Otago (S. nunni sp.n. , Waikaia Bush), and seven from the southern Alps (S. cirrhopogon sp.n. , Aspiring National Park; S. occiduus sp.n. , Westland; S. melanopogon sp.n. , Mt Dewar, Paparoa Range; S. defectus sp.n. , northern Paparoa Range; S. marrisi sp.n. , Mt Domett, Northwest Nelson; S. carinatus sp.n. , Victoria Range). Eleven synonymies are proposed: S. crenatus Broun (= S. dorsalis Broun, syn.n .), S. marginatus Pascoe (= S. bullatus Sharp, syn.n. ; S. sylvius Broun, syn.n. ; S. cordipennis Broun, syn.n. ; S. punctatus Broun, syn.n. ; S. simplex Broun, syn.n. ; S. nodosalis Broun, syn.n. ; S. truncatus Broun, syn.n. ; S. variegatus Broun, syn.n. ; S. pensus Broun, syn.n. ; S. thoracicus Broun, syn.n. ). The phylogenetic relationships among the species were reconstructed using morphological (25 adult characters) and DNA sequence (nuclear 28S rDNA and mitochondrial cytochrome c oxidase subunit I) data. A morphological analysis rooted with Trachyderastes resulted in a split between lowland and high‐altitude species and a well‐supported group from Northland. Molecular trees rooted with representatives of Trachyderastes Kaszab (New Caledonia), Meryx Latrielle (Australia), Ulodes Erichson (Australia) and three New Zealand genera (Arthopus Sharp, Brouniphylax Strand, Exohadrus Broun) resulted in the following tree: ((Ulodes, Brouniphylax) (Exohadrus, Arthopus)) (Syrphetodes (Meryx, Trachyderastes)). Species relationships within Syrphetodes included a strongly supported northern North Island clade and an alpine clade either as sister taxon to S. crenatus and S. marginatus or sister remaining lowland lineages. Combined phylogenetic analyses also showed paritial congruence with separate partitions. The distributions of the lowland species, in particular those from the North Island, correspond to islands that existed in the Pliocene. The alpine, black‐coloured lineage, found above the treeline, is monophyletic based on several characters (e.g. lack of abdominal flanges and reduced scalation) and, in some reconstructions, the tan‐coloured S. cirrhopogon is sister taxon to the remaining black‐coloured species. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:697E68E8‐EE90‐46C1‐A009‐78A794E0EF4F .     

The Detection and Differentiation of Fibrinolytic Enzymes in Bacteria

Fibrinolytic enzymes produced by various bacteria were distinguished from activators of plasminogen and were further divided into trypsin-like, thiol and metallo groups. Trypsin-like enzymes of the serine subgroup were identified by the hydrolysis of a chromogenic tripeptide substrate highly specific for plasmin and were shown to occur in a wider range of bacteria than had previously been recorded. In addition to confirming the production of enzymes of this specificity by Pseudomonas maltophilia, Achromobacter lyticus and Streptomyces griseus , similar enzymes were found in five further species of Streptomyces , in certain strains of Corynebacterium pyogenes, Micrococcus luteus and Propionibacterium acnes and also in certain species of Bacteroides and Fusobacterium.     

Short note Successive approximation in pattern analysis

The analysis of vegetation pattern in semi-arid eucalypt woodland by Harrington et al, (1981), and its recent critique by Dale (1982), place insufficient emphasis on the important role of successive approximation in pattern analysis. A single stage analysis can reveal first order patterns effectively, but is generally ineffective and inefficient in revealing vegetation patterns of higher order, no matter how sophisticated the numerical techniques employed. For a given total analytical effort, a more effective and efficient strategy to reveal such higher order patterns will generally be to partition the overall analytical effort into successive stages of sampling and interpretation, one stage for each order of pattern, with the sampling strategy at each stage based on the patterns determined during previous stages.     

The prey of the Barn owl (Tyto alba alba) in East Norfolk

Some 5000 Barn owl pellets, collected from sites in East Norfolk during the past decade, have been examined. The most important prey species, by weight, were the Field vole (Microtus agrestis) 52%, the Brown rat (Rattus norvegicus) 17%, and the Common shrew (Sorex araneus) 12%. The prey varies over different habitats; Wood mice (Apodemus sylvaticus) and Bank vole (Clethrionomys glareolus) forming a higher proportion in localities with hedges, scrub and woodland than in open grasslands. These results are comparable with those of other recent work. However, when compared with studies conducted over 30 years ago, it would appear that the Field vole now constitutes a higher proportion, and the Brown rat a lower proportion, of the prey taken.