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We examined the variation in the date of the onset of egg laying and clutch size in three peripheral populations of the Afrocanarian Blue Tits Cyanistes teneriffae ultramarinus at the edge of the species and subspecies geographic range. This study was carried out in three study sites, 130–290 km apart, in similar geographic conditions of the South Border Range of the Saharan Atlas in Algeria. Mean altitudes of nesting territories were between 1327 and 1437 m a.s.l. Habitats of the study sites were covered by the secondary, human-modified vegetation, ranging from a maquis shrubland, with the Holm oak Quercus ilex shrubs to woodlands dominated by the Atlas cedar Cedrus atlantica or by the Aleppo pine Pinus halepensis. 169 wooden nest-boxes were monitored for breeding parameters (laying dates and clutch sizes) during the breeding seasons 2007–2009 and 2011–2013. The timing of egg laying was relatively late for the latitude of the study sites, with overall mean laying dates varying between the study sites from 4 to 13 May. The laying date was influenced by the altitude of nesting sites, with the dates being delayed with increasing altitude. Overall mean clutch size differed between the study sites from 5.91 at Djelfa to 8.43 at Aflou. Clutch size tended to decrease with the advance of the breeding season. Because the study populations inhabit areas of similar physical conditions (climate and altitude), the main inter-population source of variation in the breeding parameters studied was probably variation in habitat quality.
The aim of this study was to determine the content of basic nutrients as well as selected macroand micro-elements in the albumen and yolk of eggs produced at large-scale, commercial poultry production farms (10) as well as in organic (8) and courtyard farms (12). Ten eggs were randomly collected 3 times on each farm. For chemical analyses, the eggs were hard-boiled for 15 min and then stored at a temp. of 4°C until analyzed. The albumen and yolk of hard-boiled eggs were assessed for the content of dry matter, total protein, crude fat and crude ash, and for their energy value (net Atwater equivalents) as well as the concentrations of K, Na, Ca, Mg, P, Fe, Zn, Cu, Se and Mn. No differences were observed in the content of dry matter, total protein and crude ash. However, differences were demonstrated for the crude fat content, the highest (P < 0.05) level of which was found in eggs from the organic system (higher by 60% in albumen and by 17% in yolk than in the other eggs), which was accompanied by an increased energy value of these eggs. In all the analyzed eggs, similar concentrations were noted for Mg (egg white) and P (egg albumen and yolk). The albumen of eggs from the organic system was characterized by the highest (P < 0.05) content of K, Na, Ca, Zn, Se and Mn. In turn, the albumen of eggs from large-scale commercial poultry production farms contained the highest (P < 0.05) levels of Fe, Cu and Se. Yolks of the eggs from the organic system accumulated the highest (P < 0.05) levels of K, Na, Ca, Mg and Fe. In turn, the highest (P < 0.05) concentrations of Zn, Se and Mn were determined in yolks of the eggs produced in the homestead system, and that of Cu – in yolks of the eggs from large-scale commercial production. A highly positive correlation between concentrations of minerals in the albumen and yolk of the analyzed eggs was reported for the following pairs: K-Na, Se (0.998, 0.93); Na-Na (0.949); Ca-Mg, Mn (0.994, 0.951); Mg-Ca, Mn (0.986, 0.982); P-Ca, Mn (0.997, 0.961); Fe-K, Mg, P, Zn (0.999, 0.937, 0.988, 0.999); Zn-Ca, Mn (0.999, 0.945); Se-Cu (0.971) and Mn-Ca (0.902), whereas a negative correlation for: Ca-Fe, Cu (-0.974, -0.994); Mg-Cu (-0.921); P-Fe (-0.933); Zn-Fe (-0.912); Cu-Na (-0.951); Se-K, P, Zn (-0.960, -0.910, -0.962) and Mn-Se (-0.979).
The experiments were carried out in Rzeszów, a region of the Arion lusitanicus mass occurrence, and also in Poznań. The studies were performed under field conditions, in isolators dug inio the ground. It was found that the slug began egg laying by the end of the first decade of August. The period of egg laying, depending on meteorological conditions, lasted for 2-3.5 months. The eggs were laid in clutches, each containing from 5 to 193 eggs. Most of eggs laid in August hatched before winter. For the eggs laid in mid-August the period of hatching was shorter than those laid at the turn of August/September, and the percentage of hatched eggs was lower. Eggs deposited at later dates (in September-November) did not hatch before winter.
Interactions between swarming Chironomidae and insectivorous Ceratopogonidae were observed in the field. Chironomid males of the genera Natarsia FlTTKAU, Polypedilum KlEFFER, Parachironomus LENZ, Cladotanytarsus KlEFFER, Paratanytarsus THIENEMANN et BAUSE and Tanytarsus WULP were attacked by females of Sphaeromias CURTIS, Probezzia KlEFFER, Palpomyia Meigen and Nilobezzia KlEFFER. Detailed description of egg laying in Probezzia seminigra (PANZER) is given. The genus Nilobezzia (Ceratopogonidae) and Tanytarsus verralli GOETGHEBUER (Chironomidae) are recorded in Poland for the first time.
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