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The Aquatic Warbler Acrocephalus paludicola was once a common breeding bird in mesotrophic fen mires all over Central and Western Europe. In the last century large parts of its habitat have been destroyed by wetland drainage and agricultural intensification. Besides protecting the remaining breeding habitats, it is of great importance to preserve suitable migration stopover habitats and wintering grounds to avert the extinction of the species. We determined home-range size and the use of vegetation associations of Aquatic Warblers on the wintering grounds in a flooded plain north of the Djoudj National Park in Senegal. Individual birds (11) were caught in mist nets and equipped with radio transmitters. Locations were assessed by radiotelemetry and a compositional analysis was conducted to determine which vegetation types were preferred within home ranges. Similar to their behaviour on the breeding grounds, the Aquatic Warblers showed no territorial behaviour in their winter quarters. They used home ranges that averaged 4 ha in size, which they shared with conspecifics and other warblers. The home ranges overlapped 54% on average, with a maximum of 90% in an area used by four individuals. The vegetation structure of the wintering habitat is similar to breeding grounds and stopover sites of the species. Preferential vegetation had 80% to 100% cover and consisted of 60 to 90 cm high stands of Oryza longistaminata, Scirpus maritimus or Eleocharis mutata. Most birds stayed more often near the edge of open water, probably for foraging. A constant inundation seems essential, because Aquatic Warblers never occurred in desiccated parts of the study site.
Laboratory studies were carried out on the effects of an emulsifiable concentrate (EC) formulation of Azadirachtin (AZ) (6 g a.s./l EC) on four major cotton pests in Senegal: Spodoptera littoralis Boisduval (Lepidoptera: Noctuidae), Helicoverpa armigera Hϋbner (Lepidoptera: Noctuidae), Aphis gossypii Glover (Homoptera: Aphididae) and Tetranychus urticae Koch (Acari: Tetranychidae). In both S. littoralis (SL) and H. armigera (HA), larval weight loss was observed 48 h after treatment. Appreciable weight gain was only observed in SL larvae at dosages of 0.05 and 0.1 g a.s. /l AZ, 72 h after treatment. In both SL and HA, there was a significant difference (p < 0.05) between the control larvae and those treated with 0.1 to 1.5 g a.s. /l AZ. At a dosage of 1.5 g a.s./l, AZ caused 60% mortality in SL and 0% mortality in HA, 72 h after treatment. The treatment with AZ at dosages of 0.05 and 1.5 g a.s./l resulted in 50 and 30% malformation in SL and HA pupae respectively. The duration of development from the IV instar larva to pupa in both lepidopterans increased progressively with AZ dosage. SL was more susceptible to AZ than HA. No growth disrupting effects were observed in A. gossypii (AG) and T. urticae (TU) where EC50 values of 1.49 and 1.36 g a.s./l AZ respectively were obtained. The implications of the effects of AZ on further field trials against cotton pests are discussed.
Synanthropic populations of Mastomys natalensis (A. Smith, 1834) were studied in southeastern Sénégal in order to evaluate some elements of their social structure. Analysis of trapping data consisting in single and multiple captures indicates that adult males were less likely to be involved in multiple captures than any other cate­gory of individuals. Sex-ratio in adults was significantly female-biased, and multiple captures involving 4 individuals or more (up to 13) were characterized by the small number of adult males involved (usually one per capture). Dyadic encounters between males revealed a higher rate of aggressive behaviours in M. natalensis than in its sibling species M. huberti. These observations suggest that these synanthropic populations are subdivided in polygynous units in which: (1) a part of males are evicted from the social group before their maturity and (2) adult males of different social units display aggressive behaviour towards each other.
Ultrastructural study of spermiogenesis and of the spermatozoon of Carmyerius endopapillatus has enabled to describe some characteristics of this digenea. The intercentriolar body situated between the two striated roots and the two centrioles, presents a symmetric organization. Both external bands of this intercentriolar body are made up of a row of granules. During spermiogenesis, a flagellar rotation of 90° is described. The old spermatid does not present external ornamentations. The spermatozoon is characterized, in its anterior region, by the presence of a lateral expansion exhibiting one spinelike body. In C. endopapillatus, external ornamentations are localized only at the level where the lateral expansion appears. The posterior extremity of spermatozoon exhibits a nucleus surrounded by a plasmic membrane lacking microtubules, but presenting a small lateral expansion. This is the first species of Gastrothylacidae family studied by transmission electron microscopy.
The spermiogenesis process in Wardula capitellata begins with the formation of a differentiation zone containing two centrioles associated with striated rootlets and an intercentriolar body. Each centriole develops into a free flagellum orthogonal to a median cytoplasmic process. Later these flagella rotate and become parallel to the median cytoplasmic process, which already exhibits two electron-dense areas and spinelike bodies before its proximodistal fusion with the flagella. The final stage of the spermiogenesis is characterized by the constriction of the ring of arched membranes, giving rise to the young spermatozoon, which detaches from the residual cytoplasm. The mature spermatozoon of W. capitellata presents most of the classical characters reported in digenean spermatozoa such as two axonemes of different lengths of the 9 + “1” trepaxonematan pattern, nucleus, mitochondrion, two bundles of parallel cortical microtubules and granules of glycogen. However, some peculiarities such as two lateral expansions accompanied by external ornamentation of the plasma membrane and spinelike bodies characterize the mature sperm. Moreover, a new spermatological character is described for the first time, the so-called cytoplasmic ornamented buttons.
A total of 170 wild birds from Senegal, belonging to 48 species and 9 orders, were searched for lice in 2005 and 2007. Chewing lice were found on 58 birds of 18 species and 5 orders (Columbiformes, Cuculiformes, Coraciiformes, Galliformes and Passeriformes). Twenty-two species of chewing lice of 13 genera were determined. Other nine samples of chewing lice that represent a new host-parasite association were determined at generic level only, because only one sex or nymph of these lice were found. Our records represent the first louse records from passerines Camaroptera brachyura (Cisticolidae), Chalcomitra senegalensis (Nectariniidae), Corvinella corvina (Laniidae), Laniarius barbarus (Malaconotidae), Prinia erythroptera (Cisticolidae) and Turdus pelios (Turdidae). Descriptions and illustrations are given for Brueelia chalcomitrae Najer et Sychra sp. nov. ex Chalcomitra senegalensis (Nectariniidae), Brueelia priniae Najer et Sychra sp. nov. ex Prinia subflava (Cisticolidae), and Philopteroides terpsiphoni Najer et Sychra sp. nov. ex Terpsiphone viridis (Monarchidae).
One previously described and 1 new species of Nanotrema Paperna, 1969 are reported from the gills of Citharinus citharus citharus (Citharinidae) collected from the Niokolo Koba River, Senegal. Nanotrema citharini Paperna, 1969 is redescribed, based on the re-examination of the type specimens and new information obtained from material taken in Senegal (new locality record). Nanotrema niokoloensis sp. nov. is distinguished primarily by possessing a copulatory organ composed of a long thin tube with median portion usually coiled into about 2.5 rings and an accessory piece resembling a braid lying within the rings. Based on the presence of the dorsal anchors modified into paired haptoral spikes, which lack an associated bar, species of Nanotrema phenotypically appear to be related to those of Neotropical Rhinoxenus Kritsky, Boeger et Thatcher, 1988 and Indian Spicocleidus Agrawal, Tripathi et Shukla, 2005.
The first record of monogenean parasites of the genus Macrogyrodactylus Malmberg, 1957 on freshwater fish in Senegal is presented. Macrogyrodactylus congolensis Prudhoe, 1957 from the skin and Macrogyrodactylus heterobranchii N’Douba et Lambert, 1999 from the gills of Clarias anguillaris L. were found, representing new host records for these parasites. On Polypterus senegalus Cuvier, three Macrogyrodactylus species were identified, Macrogyrodactylus polypteri Malmberg, 1957, Macrogyrodactylus simentiensis sp. nov. and Macrogyrodactylus sp. M. simentiensis sp. nov. can be readily distinguished from the other Macrogyrodactylus species by the size of its hamuli and the shape of its marginal hook sickles. The marginal hooks on the anterolateral lobes of M. simentiensis differ in size and shape from those on the posterior margin of the haptor. Measurements and drawings of the haptoral sclerites of all five identified species are provided.
Four new species of the feather mite subfamily Pterodectinae (Proctophyllodidae) are described from passerine birds examined in Senegal: Dolichodectes gymnoris sp. nov. from the Russet-browed Bush-sparrow Gymnoris dentata (Sundevall, 1850) (Passeridae), Montesauria plocei sp. nov. from the Village Weaver Ploceus cucullatus (Muller, 1776) (Ploceidae), M. zosteropis sp. nov. from the African Yellow White-eye Zosterops senegalensis Bonaparte, 1850 (Zosteropidae), and Proterothrix terpsiphone sp. nov. from the African Paradise-flycatcher Terpsiphone viridis (Muller, 1776) (Monarchidae). Brief notes on systematics and host associations of the pterodectine genera Dolichodectes Park et Atyeo, 1971, Montesauria Oudemans, 1905, and Proterothrix Gaud, 1968 are also given.
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