M. Ladle - Academia.edu (original) (raw)

Papers by M. Ladle

Research paper thumbnail of Treatment of Simulium posticatum larvae with TEKNAR HP-D (Bti) at selected sites on the River Stour, Dorset, 2006

Research paper thumbnail of An experimental treatment of Simulium posticatum with Bti at selected sites on the River Stour, Dorset, 1996

Institute of Freshwater Ecology, 1996

An experimental treatment of Simulium posticaturn with Bti at selected sites on the River Stour, ... more An experimental treatment of Simulium posticaturn with Bti at selected sites on the River Stour, Dorset, 1997.

Research paper thumbnail of An experimental treatment of Simulium posticatum with Bti at selected sites on the River Stour, Dorset, 1993

TEKNAR HP-D (Bti) was found to be an effective simuliicide when used against the larvae of Simuli... more TEKNAR HP-D (Bti) was found to be an effective simuliicide when used against the larvae of Simuliwn posticatum under the conditions prevailing in the River Stour. Laboratory tests using larvae of Sitnulium posticaturn showed that the approved concentration (0.8 ppm for ten minutes) of Bri (used in the preceding year's trials) was still effective but that a lesser concentration (0.4 ppm for ten minutes) substantially reduced mortality (77%) showing that the permitted dose is approaching the lowest effective concentration. Following preliminary surveys, six sites on the main river were selected for treatment and the furthest upstream (Blandford) and the penultimate downstream (Wimborne) of these were used for monitoring the effects of treatment. Current meter measurements were used to calculate discharges and to permit suitable dilutions of Bti to be achieved. NRA discharge records for Hammoon and Throop confumed that measurements were in the correct range. The first Bti application coincided with a flood which resulted in increased discharge and turbidity. This reduced the efficacy of the treatment. Mortality was 33% at Blandford and 59% at Wimborne. A second application several weeks later when conditions were less adverse produced mortalities of 94.9% and 77.1% at Blandford and Wimborne respectively. The overall mortalities produced by two applications of Bti were 96% and 93% at Blandford and Wimborne respectively.

Research paper thumbnail of Scanning electron microscopy of the digestive tract of larval Simulium ornatum Meigen (Complex) (Diptera: Simuliidae) and its associated microbial flora

Canadian Journal of Zoology, 1995

The structure and microbial flora of the digestive tract of larval Simulium ornatum were investig... more The structure and microbial flora of the digestive tract of larval Simulium ornatum were investigated using scanning electron microscopy. Direct observations of the microbial communities associated with the endoperitrophic surface of the peritrophic membrane and the endocuticular surface of the hindgut are presented. The endoperitrophic surface was frequently devoid of bacteria, although the fungus Harpella melusinae (Harpellales, Trichomycetes) was commonly attached. Rarely, spirochaetes and coccoid bacteria were attached to the endoperitrophic surface. In contrast, the endocuticular surface was regularly colonized by a diverse microflora composed of rod-shaped, coccoid, spiral, and filamentous bacteria and two species of Harpellales (Trichomycetes). A freeze-fracture technique is compared with a dissection technique for exposing the endoperitrophic and endocuticular surfaces of the digestive tract.

Research paper thumbnail of Temporal changes in the level of infestation of Simulium ornatum Meigen (complex) (Simuliidae: Diptera) larvae by the endosymbiotic fungus Harpella melusinae Lichtwardt (Harpellales: Trichomycetes)

Hydrobiologia, 1996

... Mark R. Taylor',*, Stephen T. Moss' & Mike Ladle2 'School of Biological Sc... more ... Mark R. Taylor',*, Stephen T. Moss' & Mike Ladle2 'School of Biological Sciences, University of Portsmouth, King Henry Building ... Members of the Harpellales infest the larvae of sev-en dipteran families (Ceratopogonidae, Chironomi-dae, Culicidae, Psychodidae, Simuliidae ...

Research paper thumbnail of Comparison of the culturable bacterial community in the midgut of larval Simulium ornatum MEIGEN (Complex) (Simuliidae: Diptera) with that of the surrounding microhabitat

Research paper thumbnail of Two sediment trap designs for use in small rivers and streams1

Limnology and Oceanography

Research paper thumbnail of Preliminary Results from a Recirculating Experimental System: Observations on Interaction between Chalk Stream Water and Inorganic Sediment

Interactions between sediments and fresh water, 1976

Research paper thumbnail of Variations in asexual reproduction in species of Entomophthora on aquatic insects

Transactions of the British Mycological Society, 1981

... been recorded from France by Zimmermann Thaxter (1888) described the fungus on dead (1978) an... more ... been recorded from France by Zimmermann Thaxter (1888) described the fungus on dead (1978) and probably erroneously by Thoizon adults of midges 'and other small gnats' along ... A long germ-rube may appear, especially when the conidium lies in the vicinity of a dead host. ...

Research paper thumbnail of Aquatic Oligochaeta of Southern England

Aquatic Oligochaete Biology, 1980

Research paper thumbnail of Aquatic Crustacea

Biology of Plant Litter Decomposition, 1974

Research paper thumbnail of Larval Simuliidae as detritus feeders in chalk streams

Mem. Ist. Ital. Idrobiol, 1972

Research paper thumbnail of Estimation of Gut Throughput Time in Gammarus Pulex under Laboratory and Field Conditions with a Note on the Feeding of Young in the Brood Pouch

Oikos, 1983

... Oikos 24: 295-300. - and Kendrick, B. 1975. Assimilation efficiency of Gam-marus pseudolimnae... more ... Oikos 24: 295-300. - and Kendrick, B. 1975. Assimilation efficiency of Gam-marus pseudolimnaeus (Amphipoda) feeding on fungal mycelium or autumn-shed leaves. ... A study on the faeces of some chalk stream invertebrates. - Hydrobiologia 74: 161-171. - and Bass, JAB ...

Research paper thumbnail of Aspects of the morphology and ecology of two British tubificids (Oligochaeta)

Journal of Zoology, 1981

ABSTRACT

Research paper thumbnail of Postspawning movements and habitat selection of dace in the River Frome, Dorset, southern England

Journal of Fish Biology, 1998

Recently spent adult dace Leuciscus leuciscus were captured from a known spawning site, radio-tag... more Recently spent adult dace Leuciscus leuciscus were captured from a known spawning site, radio-tagged and released. Post-release movements were monitored, and the habitat characteristics of the areas selected were recorded. Visual observations and electrofishing showed that all radio-tagged fish were associated with other, untagged, adult dace. After spawning, dace occupied slow-flowing shaded sites out of the main river channel. Within these areas, the fish were situated in the deepest and slowest-flowing positions available. Possible reasons for the observed postspawning behaviour and habitat selection are discussed.

Research paper thumbnail of Diel migration and site fidelity in a stream-dwelling cyprinid, Leuciscus leuciscus

Journal of Fish Biology, 1997

During May and June 1995, radio-telemetry was used to record diel movements between different, cl... more During May and June 1995, radio-telemetry was used to record diel movements between different, clearly defined daytime and night-time habitats in dace Leuciscus leuciscus. The frequent and often rapid return of individuals to previously occupied locations at dawn and dusk suggests differential habitat suitability according to light intensity, and appears similar in some respects to roosting behaviour in birds.

Research paper thumbnail of Estimation of larval feeding rates using normal linear models involving censored and truncated observations

Journal of Applied Statistics, 1990

Research paper thumbnail of The Experimental Treatment of the Blackfly, Simulium posticatum in the Dorset Stour Using the Biologically Produced Insecticide Bacillus thuringiensis var. israelensis

The Journal of Applied Ecology, 1993

Research paper thumbnail of River Ecology

The Journal of Applied Ecology, 1977

Research paper thumbnail of Studies on Three Species of Pisidium (Mollusca: Bivalvia) from a Chalk Stream

The Journal of Animal Ecology, 1969

(1) Pisidium subtruncatum and P. nitidum were the common species of this genus at Tarrant Rushton... more (1) Pisidium subtruncatum and P. nitidum were the common species of this genus at Tarrant Rushton. There was a similarity in the seasonal breeding pattern of these species, with each releasing two broods, one in June-July and one in November.(2) P. subtruncatum ...

Research paper thumbnail of Treatment of Simulium posticatum larvae with TEKNAR HP-D (Bti) at selected sites on the River Stour, Dorset, 2006

Research paper thumbnail of An experimental treatment of Simulium posticatum with Bti at selected sites on the River Stour, Dorset, 1996

Institute of Freshwater Ecology, 1996

An experimental treatment of Simulium posticaturn with Bti at selected sites on the River Stour, ... more An experimental treatment of Simulium posticaturn with Bti at selected sites on the River Stour, Dorset, 1997.

Research paper thumbnail of An experimental treatment of Simulium posticatum with Bti at selected sites on the River Stour, Dorset, 1993

TEKNAR HP-D (Bti) was found to be an effective simuliicide when used against the larvae of Simuli... more TEKNAR HP-D (Bti) was found to be an effective simuliicide when used against the larvae of Simuliwn posticatum under the conditions prevailing in the River Stour. Laboratory tests using larvae of Sitnulium posticaturn showed that the approved concentration (0.8 ppm for ten minutes) of Bri (used in the preceding year's trials) was still effective but that a lesser concentration (0.4 ppm for ten minutes) substantially reduced mortality (77%) showing that the permitted dose is approaching the lowest effective concentration. Following preliminary surveys, six sites on the main river were selected for treatment and the furthest upstream (Blandford) and the penultimate downstream (Wimborne) of these were used for monitoring the effects of treatment. Current meter measurements were used to calculate discharges and to permit suitable dilutions of Bti to be achieved. NRA discharge records for Hammoon and Throop confumed that measurements were in the correct range. The first Bti application coincided with a flood which resulted in increased discharge and turbidity. This reduced the efficacy of the treatment. Mortality was 33% at Blandford and 59% at Wimborne. A second application several weeks later when conditions were less adverse produced mortalities of 94.9% and 77.1% at Blandford and Wimborne respectively. The overall mortalities produced by two applications of Bti were 96% and 93% at Blandford and Wimborne respectively.

Research paper thumbnail of Scanning electron microscopy of the digestive tract of larval Simulium ornatum Meigen (Complex) (Diptera: Simuliidae) and its associated microbial flora

Canadian Journal of Zoology, 1995

The structure and microbial flora of the digestive tract of larval Simulium ornatum were investig... more The structure and microbial flora of the digestive tract of larval Simulium ornatum were investigated using scanning electron microscopy. Direct observations of the microbial communities associated with the endoperitrophic surface of the peritrophic membrane and the endocuticular surface of the hindgut are presented. The endoperitrophic surface was frequently devoid of bacteria, although the fungus Harpella melusinae (Harpellales, Trichomycetes) was commonly attached. Rarely, spirochaetes and coccoid bacteria were attached to the endoperitrophic surface. In contrast, the endocuticular surface was regularly colonized by a diverse microflora composed of rod-shaped, coccoid, spiral, and filamentous bacteria and two species of Harpellales (Trichomycetes). A freeze-fracture technique is compared with a dissection technique for exposing the endoperitrophic and endocuticular surfaces of the digestive tract.

Research paper thumbnail of Temporal changes in the level of infestation of Simulium ornatum Meigen (complex) (Simuliidae: Diptera) larvae by the endosymbiotic fungus Harpella melusinae Lichtwardt (Harpellales: Trichomycetes)

Hydrobiologia, 1996

... Mark R. Taylor',*, Stephen T. Moss' & Mike Ladle2 'School of Biological Sc... more ... Mark R. Taylor',*, Stephen T. Moss' & Mike Ladle2 'School of Biological Sciences, University of Portsmouth, King Henry Building ... Members of the Harpellales infest the larvae of sev-en dipteran families (Ceratopogonidae, Chironomi-dae, Culicidae, Psychodidae, Simuliidae ...

Research paper thumbnail of Comparison of the culturable bacterial community in the midgut of larval Simulium ornatum MEIGEN (Complex) (Simuliidae: Diptera) with that of the surrounding microhabitat

Research paper thumbnail of Two sediment trap designs for use in small rivers and streams1

Limnology and Oceanography

Research paper thumbnail of Preliminary Results from a Recirculating Experimental System: Observations on Interaction between Chalk Stream Water and Inorganic Sediment

Interactions between sediments and fresh water, 1976

Research paper thumbnail of Variations in asexual reproduction in species of Entomophthora on aquatic insects

Transactions of the British Mycological Society, 1981

... been recorded from France by Zimmermann Thaxter (1888) described the fungus on dead (1978) an... more ... been recorded from France by Zimmermann Thaxter (1888) described the fungus on dead (1978) and probably erroneously by Thoizon adults of midges 'and other small gnats' along ... A long germ-rube may appear, especially when the conidium lies in the vicinity of a dead host. ...

Research paper thumbnail of Aquatic Oligochaeta of Southern England

Aquatic Oligochaete Biology, 1980

Research paper thumbnail of Aquatic Crustacea

Biology of Plant Litter Decomposition, 1974

Research paper thumbnail of Larval Simuliidae as detritus feeders in chalk streams

Mem. Ist. Ital. Idrobiol, 1972

Research paper thumbnail of Estimation of Gut Throughput Time in Gammarus Pulex under Laboratory and Field Conditions with a Note on the Feeding of Young in the Brood Pouch

Oikos, 1983

... Oikos 24: 295-300. - and Kendrick, B. 1975. Assimilation efficiency of Gam-marus pseudolimnae... more ... Oikos 24: 295-300. - and Kendrick, B. 1975. Assimilation efficiency of Gam-marus pseudolimnaeus (Amphipoda) feeding on fungal mycelium or autumn-shed leaves. ... A study on the faeces of some chalk stream invertebrates. - Hydrobiologia 74: 161-171. - and Bass, JAB ...

Research paper thumbnail of Aspects of the morphology and ecology of two British tubificids (Oligochaeta)

Journal of Zoology, 1981

ABSTRACT

Research paper thumbnail of Postspawning movements and habitat selection of dace in the River Frome, Dorset, southern England

Journal of Fish Biology, 1998

Recently spent adult dace Leuciscus leuciscus were captured from a known spawning site, radio-tag... more Recently spent adult dace Leuciscus leuciscus were captured from a known spawning site, radio-tagged and released. Post-release movements were monitored, and the habitat characteristics of the areas selected were recorded. Visual observations and electrofishing showed that all radio-tagged fish were associated with other, untagged, adult dace. After spawning, dace occupied slow-flowing shaded sites out of the main river channel. Within these areas, the fish were situated in the deepest and slowest-flowing positions available. Possible reasons for the observed postspawning behaviour and habitat selection are discussed.

Research paper thumbnail of Diel migration and site fidelity in a stream-dwelling cyprinid, Leuciscus leuciscus

Journal of Fish Biology, 1997

During May and June 1995, radio-telemetry was used to record diel movements between different, cl... more During May and June 1995, radio-telemetry was used to record diel movements between different, clearly defined daytime and night-time habitats in dace Leuciscus leuciscus. The frequent and often rapid return of individuals to previously occupied locations at dawn and dusk suggests differential habitat suitability according to light intensity, and appears similar in some respects to roosting behaviour in birds.

Research paper thumbnail of Estimation of larval feeding rates using normal linear models involving censored and truncated observations

Journal of Applied Statistics, 1990

Research paper thumbnail of The Experimental Treatment of the Blackfly, Simulium posticatum in the Dorset Stour Using the Biologically Produced Insecticide Bacillus thuringiensis var. israelensis

The Journal of Applied Ecology, 1993

Research paper thumbnail of River Ecology

The Journal of Applied Ecology, 1977

Research paper thumbnail of Studies on Three Species of Pisidium (Mollusca: Bivalvia) from a Chalk Stream

The Journal of Animal Ecology, 1969

(1) Pisidium subtruncatum and P. nitidum were the common species of this genus at Tarrant Rushton... more (1) Pisidium subtruncatum and P. nitidum were the common species of this genus at Tarrant Rushton. There was a similarity in the seasonal breeding pattern of these species, with each releasing two broods, one in June-July and one in November.(2) P. subtruncatum ...