Sedimentation is widely acknowledged as a major cause of degradation of instream habitats. Howeve... more Sedimentation is widely acknowledged as a major cause of degradation of instream habitats. However, macroinvertebrate burial by sediment has been poorly studied. Ex situ experiments were undertaken to examine the response of four common and abundant macroinvertebrate taxa (Baetis rhodani, Nemoura cambrica, Hydropsyche pellucidula, and Asellus aquaticus) to burial by six sediment size classes (range = 125 m 10 mm in size) and two depths of burial (5 mm and 10 mm). The nymphs of the ephemeropteran, Baetis rhodani, were unable to excavate themselves from any of the sediments. In contrast, the plecopteran nymphs of Nemoura cambrica were able to excavate themselves from all sediment classes and burial depths. Adults of the isopod, Asellus aquaticus, were able to excavate themselves rapidly from finer sediment classes (< 1 mm) but took significantly longer to escape from sediment > 1 mm in size and became trapped in coarser sediments (>4 mm in size at 5 mm burial depth and >...
An Insect Activity Monitor was created to measure the behavioural responses of fleas (Siphonapter... more An Insect Activity Monitor was created to measure the behavioural responses of fleas (Siphonaptera). The apparatus allows for a range of visual, chemo- and mechanoreceptor cues to be presented. The jumping response is detected by counting amplified pulses produced as the fleas land on a stretched membrane held over a microphone. Horizontal movements are detected using a system of infra-red beams and phototransistors which, when broken, are counted as a measure of activity. The apparatus was tested using Ceratophyllus hirundinis (Curtis), Ceratophyllus farreni (Rothschild) and Ceratophyllus rusticus (Wagner), co-inhabiting species from the nests of the house martin (Delichon u.urbica L.). No unaided emigration or immigration has been demonstrated in these species (Clark, 1988) and much of their time is spent confined to the darkness of the nest. In addition to species contrasts, females were more active than males and fleas were more active at 25 degrees C than at 18 degrees C. The more active bird flea Ceratophyllus garei (Rothschild) from the nest of pheasant (Phasianus colchicus L), was tested for responses to light of varying intensity. Activity was stimulated by white light, but not proportional to light intensity.
Host choice and fecundity are two factors that may contribute to the variation in flea counts obs... more Host choice and fecundity are two factors that may contribute to the variation in flea counts observed when assessing the potential risk of flea-borne transmission of pathogens from rodents to humans. Using the black rat, Rattus rattus Linnaeus, as host the effects of age and sex on host choice and fecundity of the Oriental rat flea, Xenopsylla cheopis Rothschild, were examined experimentally at 25°C and 80% rh. During the first two days of emergence from cocoons, female fleas dominated the sex ratio by 4:1 but from the third day onwards this switched to a male-dominated sex ratio of 4:1. The sex of the flea did not influence their host-seeking behaviour. Newly emerged fleas of both sexes were not influenced by the rat‘s presence and at seven days old both sexes demonstrated similar levels of attraction toward the rat host. The sex of the rat did not affect flea host-seeking behaviour. There was a 50–70% decline in the initial number of adult fleas during the first week after their ...
The mites (Acari) found in seven nests of the Dipper, Cinclus cinclus aquaticus Bechstein, in Wal... more The mites (Acari) found in seven nests of the Dipper, Cinclus cinclus aquaticus Bechstein, in Wales, British Isles, are studied. They belong to 54 species, included in 46 genera, 27 families and 4 orders. This collection includes several stored food pests or species able to invade houses or to produce respiratory allergies in man, e.g. Tyrophagus putrescentiae (Schrank), T. longior (Gervais), T. palmarum Oudemans, Acarus farris (Oudemans), Dermatophagoides farinae Hughes and Kleemannia plumigera (Oudemans). Several fleas, Dasypsyllus g. gallinae (Dale), found in one nest, were parasitized by phoretic hypopi of Acarus avicolus Fain and Beaucournu. Tyrophagus nidicola Dambre-Raes, 1974, is considered here as a synonym of Tyrophagus palmarum Oudemans, 1924.
Journal of vector ecology : journal of the Society for Vector Ecology, 1999
Circadian rhythm in newly emerged blood-fed individuals of the flea Ceratophyllus s. sciurorum wa... more Circadian rhythm in newly emerged blood-fed individuals of the flea Ceratophyllus s. sciurorum was studied in a constant environment, using an insect activity monitor. The results of trials run continuously over seven days confirmed the finding that C. s. sciurorum has a self-sustaining clock. Statistical tests confirm that feeding weakens the rhythm but does not eliminate it. There was a significant difference in the mean activity between the fed and unfed fleas, reflecting the difference in the number of hours over which this activity took place. A possible commercial application for the monitor and also for the method of analysis is discussed.
The distribution of the different units within a hydrosystem is related to the geomorphological m... more The distribution of the different units within a hydrosystem is related to the geomorphological mechanisms involved in their creation (Chapter 5). In addition to the effects of the environmental constraints specific to each unit (Chapters 6, 7 and 8), the composition of the populations in each unit also depends on their spatial relations because of exchanges and interactions between them. Some species need to be close to different complementary units for their development, or for re-establishment after disturbance. The hydrosystem as a whole has a resilience, with some units within it acting as refugia or foci for recolonization.
The role of the louse Trinoton anserinum (F) as an intermediate host of Sarconema eurycerca (Wehr... more The role of the louse Trinoton anserinum (F) as an intermediate host of Sarconema eurycerca (Wehr) was investigated in swans. 8.3% of healthy swans carried one to twelve lice per bird, dispersed contagiously. Injured and lead-poisoned swans were more heavily infected. The mouthparts appear designed to penetrate the hosts&#39; skin; the mandibles are robust and asymmetric, and the maxillae have a serrated intercutting surface. 22% fed exclusively on blood and 33% on both blood and feather. All life-cycle stages fed upon blood and the barbs and barbules from down feathers; hooklets from contour feathers were only found in adults. 9% of lice were infected with developing nematode larvae in the head, thorax or abdomen. Lice labelled with Technetium 99 m moved towards the scapulas and the wings. Lice were found to be highly active and were mobile.
Page 1. ORIGINAL PAPER Reconstructing riverine paleo-flow regimes using subfossil insects (Coleop... more Page 1. ORIGINAL PAPER Reconstructing riverine paleo-flow regimes using subfossil insects (Coleoptera and Trichoptera): the application of the LIFE methodology to paleochannel sediments Lynda C. Howard Æ Paul J. Wood Æ Malcolm T. Greenwood Æ Helen M. Rendell ...
Sedimentation is widely acknowledged as a major cause of degradation of instream habitats. Howeve... more Sedimentation is widely acknowledged as a major cause of degradation of instream habitats. However, macroinvertebrate burial by sediment has been poorly studied. Ex situ experiments were undertaken to examine the response of four common and abundant macroinvertebrate taxa (Baetis rhodani, Nemoura cambrica, Hydropsyche pellucidula, and Asellus aquaticus) to burial by six sediment size classes (range = 125 m 10 mm in size) and two depths of burial (5 mm and 10 mm). The nymphs of the ephemeropteran, Baetis rhodani, were unable to excavate themselves from any of the sediments. In contrast, the plecopteran nymphs of Nemoura cambrica were able to excavate themselves from all sediment classes and burial depths. Adults of the isopod, Asellus aquaticus, were able to excavate themselves rapidly from finer sediment classes (< 1 mm) but took significantly longer to escape from sediment > 1 mm in size and became trapped in coarser sediments (>4 mm in size at 5 mm burial depth and >...
An Insect Activity Monitor was created to measure the behavioural responses of fleas (Siphonapter... more An Insect Activity Monitor was created to measure the behavioural responses of fleas (Siphonaptera). The apparatus allows for a range of visual, chemo- and mechanoreceptor cues to be presented. The jumping response is detected by counting amplified pulses produced as the fleas land on a stretched membrane held over a microphone. Horizontal movements are detected using a system of infra-red beams and phototransistors which, when broken, are counted as a measure of activity. The apparatus was tested using Ceratophyllus hirundinis (Curtis), Ceratophyllus farreni (Rothschild) and Ceratophyllus rusticus (Wagner), co-inhabiting species from the nests of the house martin (Delichon u.urbica L.). No unaided emigration or immigration has been demonstrated in these species (Clark, 1988) and much of their time is spent confined to the darkness of the nest. In addition to species contrasts, females were more active than males and fleas were more active at 25 degrees C than at 18 degrees C. The more active bird flea Ceratophyllus garei (Rothschild) from the nest of pheasant (Phasianus colchicus L), was tested for responses to light of varying intensity. Activity was stimulated by white light, but not proportional to light intensity.
Host choice and fecundity are two factors that may contribute to the variation in flea counts obs... more Host choice and fecundity are two factors that may contribute to the variation in flea counts observed when assessing the potential risk of flea-borne transmission of pathogens from rodents to humans. Using the black rat, Rattus rattus Linnaeus, as host the effects of age and sex on host choice and fecundity of the Oriental rat flea, Xenopsylla cheopis Rothschild, were examined experimentally at 25°C and 80% rh. During the first two days of emergence from cocoons, female fleas dominated the sex ratio by 4:1 but from the third day onwards this switched to a male-dominated sex ratio of 4:1. The sex of the flea did not influence their host-seeking behaviour. Newly emerged fleas of both sexes were not influenced by the rat‘s presence and at seven days old both sexes demonstrated similar levels of attraction toward the rat host. The sex of the rat did not affect flea host-seeking behaviour. There was a 50–70% decline in the initial number of adult fleas during the first week after their ...
The mites (Acari) found in seven nests of the Dipper, Cinclus cinclus aquaticus Bechstein, in Wal... more The mites (Acari) found in seven nests of the Dipper, Cinclus cinclus aquaticus Bechstein, in Wales, British Isles, are studied. They belong to 54 species, included in 46 genera, 27 families and 4 orders. This collection includes several stored food pests or species able to invade houses or to produce respiratory allergies in man, e.g. Tyrophagus putrescentiae (Schrank), T. longior (Gervais), T. palmarum Oudemans, Acarus farris (Oudemans), Dermatophagoides farinae Hughes and Kleemannia plumigera (Oudemans). Several fleas, Dasypsyllus g. gallinae (Dale), found in one nest, were parasitized by phoretic hypopi of Acarus avicolus Fain and Beaucournu. Tyrophagus nidicola Dambre-Raes, 1974, is considered here as a synonym of Tyrophagus palmarum Oudemans, 1924.
Journal of vector ecology : journal of the Society for Vector Ecology, 1999
Circadian rhythm in newly emerged blood-fed individuals of the flea Ceratophyllus s. sciurorum wa... more Circadian rhythm in newly emerged blood-fed individuals of the flea Ceratophyllus s. sciurorum was studied in a constant environment, using an insect activity monitor. The results of trials run continuously over seven days confirmed the finding that C. s. sciurorum has a self-sustaining clock. Statistical tests confirm that feeding weakens the rhythm but does not eliminate it. There was a significant difference in the mean activity between the fed and unfed fleas, reflecting the difference in the number of hours over which this activity took place. A possible commercial application for the monitor and also for the method of analysis is discussed.
The distribution of the different units within a hydrosystem is related to the geomorphological m... more The distribution of the different units within a hydrosystem is related to the geomorphological mechanisms involved in their creation (Chapter 5). In addition to the effects of the environmental constraints specific to each unit (Chapters 6, 7 and 8), the composition of the populations in each unit also depends on their spatial relations because of exchanges and interactions between them. Some species need to be close to different complementary units for their development, or for re-establishment after disturbance. The hydrosystem as a whole has a resilience, with some units within it acting as refugia or foci for recolonization.
The role of the louse Trinoton anserinum (F) as an intermediate host of Sarconema eurycerca (Wehr... more The role of the louse Trinoton anserinum (F) as an intermediate host of Sarconema eurycerca (Wehr) was investigated in swans. 8.3% of healthy swans carried one to twelve lice per bird, dispersed contagiously. Injured and lead-poisoned swans were more heavily infected. The mouthparts appear designed to penetrate the hosts&#39; skin; the mandibles are robust and asymmetric, and the maxillae have a serrated intercutting surface. 22% fed exclusively on blood and 33% on both blood and feather. All life-cycle stages fed upon blood and the barbs and barbules from down feathers; hooklets from contour feathers were only found in adults. 9% of lice were infected with developing nematode larvae in the head, thorax or abdomen. Lice labelled with Technetium 99 m moved towards the scapulas and the wings. Lice were found to be highly active and were mobile.
Page 1. ORIGINAL PAPER Reconstructing riverine paleo-flow regimes using subfossil insects (Coleop... more Page 1. ORIGINAL PAPER Reconstructing riverine paleo-flow regimes using subfossil insects (Coleoptera and Trichoptera): the application of the LIFE methodology to paleochannel sediments Lynda C. Howard Æ Paul J. Wood Æ Malcolm T. Greenwood Æ Helen M. Rendell ...
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