A spatial analytical approach for selecting reintroduction sites for burbot in English rivers

1. Availability of suitable habitat is a prerequisite for species reintroduction success, and to ensure population persistence, investigations of a species’ habitat utilisation throughout its life history should be conducted as part of a feasibility study. 2. Habitat utilisation models for burbot, Lota lota, developed using data from field studies conducted in France and Germany and information from the literature were used to assess the feasibility of reintroducing burbot into rivers of its former native range in eastern England. 3. Per cent tree roots, aquatic vegetation and flow types were important predictors of adult burbot abundance. Furthermore, the habitat utilisation models were supplemented with information from the literature, which suggested that off‐channel habitat such as wetlands and backwaters is important for spawning and nursery stages. 4. An assessment of the habitat availability in the rivers of the burbot’s former native range using variables related to spawning and nursery and adult life stages showed that although adult habitat was widely distributed, the availability of spawning and nursery habitat was less abundant, potentially limiting successful reestablishment. 5. Potential suitable habitat was concentrated in the central and southern areas of the species’ former English distribution. Overall, rivers of the burbot’s former range potentially afford suitable habitat to sustain a reintroduced population. However, sites should be preferentially selected on the basis of having appropriate spawning and nursery areas.     

Distribution of the neurotoxic nonprotein amino acid BMAA in Cycas micronesica

BMAA (β-methylamino-L-alanine), a nonprotein amino acid with neurotoxic properties occurs in the cycad Cycas micronesica Hill in Guam. BMAA may have originally played a role as an antiherbivory compound in the plant, but is now of great interest because of its possible link to ALS-PDC, a neurological disease among the Chamorro people of Guam. Biomagnified cycad neurotoxins may play a role because they accumulate in flying foxes of the genus Pteropus that are eaten during traditional feasts. Since flying foxes feed on the seed sarcotesta it is important to understand the distribution of BMAA in the various tissues of the cycad. Using HPLC techniques, we quantified both BMAA and glutamic acid (GLU) in all cycad tissues. Although GLU is distributed randomly throughout the plant, BMAA is concentrated in cycad reproductive organs, with the highest concentrations being found in the immature staminate sporangium and the outmost layer of the sarcotesta. This finding is consistent with the putative evolutionary role of BMAA as an antiherbivory compound, as well as the biomagnification of the compound in flying foxes that ingest the seed sarcotesta.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 165–168.     

Hemolysis considered as a progressive reaction in a heterogeneous system

It is demonstrated, without the use of special assumptions, that red cells are heterogeneous with respect to their resistance to at least certain lysins, that the reaction between the cell components and the lysin is virtually irreversible in some cases but reversible, although to different extents, in others, and that the lysin initiates a process in the cell which is not adequately described by the terms reversible and irreversible, but rather by the term progressive. Progressive reactions, i.e. reactions which cannot be stopped once they are well under way, may be looked for in systems which have structure, and in which local reactions occurring at strategic points lead to disproportionate results.     

Testosterone,growth and the evolution of sexual size dimorphism

The integration of macroevolutionary pattern with developmental mechanism presents an outstanding challenge for studies of phenotypic evolution. Here, we use a combination of experimental and comparative data to test whether evolutionary shifts in the direction of sexual size dimorphism (SSD) correspond to underlying changes in the endocrine regulation of growth. First, we combine captive breeding studies with mark‐recapture data to show that male‐biased SSD develops in the brown anole lizard (Anolis sagrei) because males grow significantly faster than females as juveniles and adults. We then use castration surgeries and testosterone implants to show that castration inhibits, and testosterone stimulates, male growth. We conclude by reviewing published testosterone manipulations in other squamate reptiles in the context of evolutionary patterns in SSD. Collectively, these studies reveal that the evolution of SSD has been accompanied by underlying changes in the effect of testosterone on male growth, potentially facilitating the rapid evolution of SSD.