Management strategy influences landscape patterns of high-severity burn patches in the southwestern United States

Landscape Ecology - Spatial patterns of high-severity wildfire in forests affect vegetation recovery pathways, watershed dynamics, and wildlife habitat across landscapes. Yet, less is known about...     

Movement patterns of Brook Trout in a restored coastal stream system in southern Massachusetts

Coastal Brook Trout (Salvelinus fontinalis) populations are found from northern Canada to New England. The extent of anadromy generally decreases with latitude, but the ecology and movements of more southern populations are poorly understood. We conducted a 33‐month acoustic telemetry study of Brook Trout in Red Brook, MA, and adjacent Buttermilk Bay (marine system) using 16 fixed acoustic receivers and surgically implanting acoustic transmitters in 84 individuals. Tagged Brook Trout used the stream, estuary (50% of individuals) and bay (10% of individuals). Movements into full sea water were brief when occurring. GAMM models revealed that transitions between habitat areas occurred most often in spring and fall. Environmental data suggest that use of the saline environment is limited by summer temperatures in the bay. Movements may also be related to moon phase. Compared to more northern coastal populations of Brook Trout, the Red Brook population appears to be less anadromous overall, yet the estuarine segment of the system may have considerable ecological importance as a food resource.     

The pyrethrins and related compounds. Part XXXV. Esters of aryl-substituted cyclopentane alcohols and analogues

Synthesis of a range of 1-, 2-and 3-phenyl, benzyl and phenethyl substituted cyclopentanols and cyclopentylmethyl alcohols and related unsaturated compounds is reported. Results of bioassays of their esters with known pyrethroidal acids against two species of insect lead to recognition of some structure-activity relationships in this series. The distance and relative orientation between the alcoholic and aryl functions appears crucial, but in other respects the nature of the spacer group between them is less important. The most effective alcoholic components are based on cyclopentenes.     

The pyrethrins and related compounds. Part XXXIV. Optimisation of insecticidal activity in non-esters

Optimisation of activity within the structural constraints defined by the preceding work, by varying the substituents on phenyl in the acid fragment (10 variations), the nature of the group fulfilling the dimethyl function (three variations), the central linking group (four variations) and the presence or absence of a 4-fluoro substituent in the alcohol fragment, has led to achiral compounds as active as bioresmethrin against houseflies and mustard beetles. Statistical analysis of the effects has shown that particular combinations, for instance the cyclopropyl form of dimethyl with a central E-alkene group (but not a central ether group), lead to higher activity than expected. 4-Fluoro substitution enhances activity more strongly against mustard beetles. Difluorocyclopropyl compounds are on average slightly more active than cyclopropyl analogues.     

Insecticide resistance in the bollworm,Helicoverpa armigera from Indonesia

Helicoverpa armigera collected from cotton growing areas of South Sulawesi, Indonesia in 1987 and early 1988 were resistant to cypermethrin. It is suggested that the 86-fold resistance to cis-cypermethrin in 1987 and the 65-fold resistance to cis/trans-cypermethrin in 1988 are consistent with this being a major cause of failure to control the insects in cotton in this area. The second laboratory generation showed a 20-fold resistance to fenvalerate. The larvae collected in 1988 additionally had a 203-fold resistance to DDT and a 5.6-fold resistance to endosulfan. The results are discussed in relation to the fact that this is a further region in which Helicoverpa armigera has developed resistance to a number of pyrethroids.     

Occurrence of Piscirickettsiosis-like syndrome in tilapia in the continental United States.

From 2001 to 2003, tilapia (Oreochromis sp.) farms in Florida, California, and South Carolina experienced epizootics of a systemic disease causing mortality. The fish exhibited lethargy, occasional exophthalmia, and skin petechia. The gills were often necrotic, with a patchy white and red appearance. Grossly, the spleen and kidneys were granular with whitish irregular nodules throughout. Granulomatous infiltrates were observed in kidney, spleen, testes, and ovary tissues, but not in the liver. The granulomas contained pleomorphic coccoid bacteria, measuring 0.57 +/- 0.1 x 0.8 +/- 0.2 microm, that were Giemsa-positive, acid-fast-negative, and Gram-negative. The bacteria had a double cell wall, variable electron-dense and -lucent areas, and were present in the cytoplasm and within phagolysosomes. The syndrome was associated with cold stress and poor water conditions. These findings are consistent with an infectious process caused by a Piscirickettsia-like bacterium described previously in tilapia in Taiwan and Hawaii. This report involves the first identified cases of a piscirickettsiosis-like syndrome affecting tilapia in the continental United States.