Variation In Feeding Patterns Research Articles

Carnivore home-range size, metabolic needs and ecology

Relationships between home-range size, metabolic needs of the animals occupying the homerange, and ecology are examined across species in the order Carnivora. Home-range size increases with metabolic needs, irrespective of taxonomic affinity. When the effects of metabolic needs are removed, among ecological variables (including activity pattern, habitat, diet and zonation) only diet shows a significant influence on home-range size. Carnivores with a large proportion of flesh in their diets have particularly large home-ranges. Intraspecific variation in feeding patterns as a determinant of variation in home-range size is emphasized.

Effects of prey density and site character on estuary usage by overwintering waders (Charadrii)

The usage by wading birds of 14 sites on the Forth Estuary in winter was examined in relation to the density of their invertebrate prey and the area, configuration and exposure sequence of the intertidal sites. Six common waders were studied over the whole estuary and three species in greater detail at the largest single site. Significant associations were shown in five species for feeding-hours km −2 and numbers km −2 with the density of at least one of their main prey; including oystercatchers Haematopus ostralegus (L.) with Mytilus edulis (L.); curlew Numenius arquata (L.) with Nereis diversicolor (L.); redshank Tringa totanus (L.) with Nereis diversicolor; knot Calidris canutus (L.) with Cerastoderma edule (L.) and dunlin Calidris alpina (L.) with Nereis diversicolor. For four species site characteristics also apparently affected feeding patterns [bar-tailed godwit Limosa lapponica (L.), area; redshank, exposure sequence; knot, area, configuration and exposure sequence; dunlin, area]. Overall, significant variables explained 43–96% of the variation in wader feeding-hours km −2 on the estuary and 41–87% of numbers km −2. It is emphasised however, that the observed variation in feeding patterns on the Forth Estuary represents only a part of the total variation in usage of estuaries by feeding waders and further studies are necessary to explain the extent and causes of this additional variability.

Iron deficiency: impaired liver growth and DNA synthesis in the rat.

Summary. This study deals with liver growth and DNA synthesis in young, rapidly growing rats weaned to an iron deficient diet. Shortly after the development of anaemia there was a depression in the rate of liver growth that was more profound than that of body growth. The rate of increase in total liver DNA was similarly depressed, in comparison with iron‐supplemented animals. Paradoxically, in the deficient rats, two normally sensitive indices of DNA synthesis, incorporation of [3H]thymidine into DNA and activity of thymidine kinase, were unaffected. This was also the case in animals acclimated to a 4 hr/day restricted feeding regimen in order to control for possible variations in feeding patterns. Although [3H]thymidine incorporation was normal throughout a 24 hr period, incorporation of 32P into liver DNA was depressed in the iron deficient rats. The results indicate changes in liver DNA synthesis due to iron deficiency that are distinct from those seen in starvation and protein‐calorie malnutrition. Probably DNA synthesis in iron deficiency is modified through a depression of de novo synthesis, in the presence of normal salvage pathway activity.

Variations in feeding patterns of seven culicine mosquitoes on vertebrate hosts in Weld and Larimer Counties, Colorado.

SummaryEngorged specimens of seven mosquito species, Culex tarsalis, Culex pipiens, Culiseta inornata, and four species of Aedes were collected in Weld and Larimer Counties, Colorado, during 1963, 1964, and 1965. The blood-meals were identified by precipitin tests. C. tarsalis had fed a high proportion of the time on birds and on mammals. In May of 1963 and 1964, there was an increase in mammalian blood-meals during a 2-week period, and a similar increase occurred during the week of May 31 in 1965. Increased mammalian feeding by C. tarsalis also was noted during July, August, and early September in 1963 and 1964, when mosquito populations were high. C. pipiens feedings were compared with those of C. tarsalis at one site. C. pipiens fed almost exclusively on birds; whereas C. tarsalis fed in a pattern similar to that found in other study areas. C. inornata and Aedes spp. fed almost exclusively on domestic mammals, predominantly cattle.

GROWTH OF "WELL-BORN" AMERICAN INFANTS FED HUMAN AND COW'S MILK

Weight and length of 599 well-born, healthy infants were recorded from birth through six months of age. Two hundred ninety-three (293) of the infants were breast fed and 306 were artificially fed; 57 of the breast-fed boys and 32 of the breastfed girls were observed for one year. Variations in feeding patterns were recorded to evaluate the effects of such variations on growth. The consistency and predictability of growth in length of normal infants is emphasized. The aggregate growth curves of the total 599 infants are similar to the Iowa Growth norms of 1945. They differ in that, compared to the Iowa norms, the girls are slightly taller, and after the second month of life, the boys' weight gain is somewhat less. More worldwide effort to collect accurate weight and length values for healthy, well-born infants given optimum care is needed to establish normal growth standards for various ethnic groups living in different areas of the world.