Development of the Swine Coccidium Eimeria debliecki Douwes, 1921 in Mammalian Cell Cultures1

Sporozoites of Eimeria debliecki entered human fetal lung and porcine kidney cells grown in cultures and underwent one merogenous cycle, terminating in the production of second-generation trophozoites. Sporozoites were intracellular 1 h post-inoculation (PI) and developed into sporozoite-shaped meronts at 40 h PI. These meronts, one of which was motile, had from two to ten nuclei. Sporozoite-shaped meronts then developed into elongate or spheroidal meronts with 10 to 24 nuclei by two days PI. Ten to 26 first-generation merozoites were formed by budding from the meront surface. Mature first-generation merozoites were most numerous three days PI. Most meronts had ruptured and released nonmotile merozoites into the culture medium by four days PI. Merozoites that were not released became rounded and developed into second-generation trophozoites. Refractile bodies were present in all developmental stages. No further development was observed five through eight days PI.     

Systematic Zoology: Slicing the Gordian Knot with Ockham's Razor

Systematic zoology has undergone a revolution during the past25 years. A major step was in the formulation of an explicitand objective methodology for determining phylogenetic relationshipsthat results in testable hypotheses. The methodology of phylogeneticsystematics has spawned vicariance biogeography and is applicablenot only to traditional morphological characters but to newkinds of systematic characters. Innovative biochemical, cytogenetic,and developmental approaches to phylogenetic relationships havebroadened the scope of systematic zoology. This diversity increasesthe potential for generating and testing hypotheses of phylogeneticrelationships and temporal evolution.     

Pollen-feeding and the host specificity and fecundity of flower thrips (Thysanoptera)

Abstract. 1. Flower thrips could feed on pollen of a wide range of sizes and were unaffected by exine spines. One species of thrips was unable to feed on very adhesive grains.
2. The proportion of time spent feeding on each species of pollen (in seconds per minute of exposure) reflected the known host specificities. Host-specific thrips could distinguish their host pollen, apparently without probing.
3. Kakothrips pisivorus (Westwood) appeared to have a higher rate of ingestion of a host pollen than of four non-host pollens.
4. In cages in the laboratory, Thrips fuscipennis Haliday laid significantly more eggs over 48h when given pollen than when given other floral tissues or no food. K. pisivonis and Ceratothrips ericae (Haliday) also laid significantly more eggs over 48h in the presence of pollen than in its absence.
5. In comparisons between pollen diets, T. fuscipennis, a generalist, laid similar numbers of eggs with each species of pollen, but K. pisivorus and C. ericae laid significantly more eggs with their respective host pollens. The differences in oviposition rate between pollen diets reflected the differences in the proportion of time spent feeding.     

The Health and Nutrition of a Medieval Nubian Population

Human remains from two cemeteries at Kulubnarti in Sudanese Nubia present an ideal opportunity to assess the biological impact of political and economic change. Remains from the early cemetery come from Nubia's medieval period, characterized by political unification and important achievements in art and architecture. Remains from the second cemetery come from the later emergent feudal age, characterized by regional isolation and return to a subsistence economy. Patterns of mortality, growth, development, nutrition, and disease revealed by the remains converge on one conclusion: the transformation from the medieval to the feudal age at Kulubnarti witnessed an improvement in human health and survival.     

Temporal Patterns of Territorial Behavior and Circulating Testosterone in the Lapland Longspur and Other Arctic Passerines

We studied territorial aggression in relation to circulatingtestosterone levels in free-living birds of four species innorthern Alaska. The Lapland longspur, Calcarius lapponicus,is an abundant breeding passerine on the arctic tundra. Unlikemany passerines at lower latitudes, male Lapland longspurs donot defend a "multiple-purpose territory" that serves to providenest sites, food and shelter. Rather, after arrival on the breedinggrounds, they perform aerial display flights over a looselydenned "nest area" for a very brief period of two days or so,showing tolerance of other males. This song display may be involvedin courtship. During this phase, male longspurs show a briefand pronounced peak in circulating testosterone levels, andare not aggressive toward simulated territorial intrusions (STIs).Males then "guard" their sexually receptive mates for aboutten days, during which they are highly aggressive toward STIs,but do not sing as much. During the next phase, incubation,the males become very tolerant of conspecific males. Their circulatingtestosterone levels decline to baseline levels, and they generallydo not sing or display aggression in response to STIs. Threeother passerines, the white-crowned sparrow, Zonotrichia leucophrysgambelii, American tree sparrow, Spizella arborea, and savannahsparrow, Passerculus sandwichensis, show patterns of territorialaggression typical of species studied at lower latitudes. Welldefinedterritories are defended for several weeks, during which thereis a prolonged peak in plasma concentrations of testosterone.These three species continue to sing and display aggressioneven late in the season, unlike the longspurs. The peak of testosteronein the longspurs occurs simultaneously with the peak in songdisplay, while in mid-latitude species it occurs with the peakin reproductive aggression. These data suggest that the interrelationshipof testosterone and aggression in Lapland longspurs may be differentfrom that of passerines with multiple-purpose territories, andmay be related to the constraints of breeding in the open arctictundra.     

Tonganoxichnus a new insect trace from the Upper Carboniferous of eastern Kansas

Upper Carboniferous tidal rhythmites of the Tonganoxie Sandstone Member (Stranger Formation) at Buildex Quarry, eastern Kansas, USA, host a relatively diverse arthropod-dominated ichnofauna. Bilaterally symmetrical traces displaying unique anterior and posterior sets of morphological features are well represented within the assemblage. A new ichnogenus, Tonganoxichnus, is proposed for these traces. T. buildexensis, the type ichnospecies, has an anterior region characterized by the presence of a frontal pair of maxillary palp impressions, followed by a head impression and three pairs of conspicuous thoracic appendage imprints symmetrically opposite along a median axis. The posterior region commonly exhibits numerous delicate chevron-like markings, recording the abdominal appendages, and a thin, straight, terminal extension. T. buildexensis is interpreted as a resting trace. A second ichnospecies, T. ottawensis, is characterized by a fan-like arrangement of mostly bifid scratch marks at the anterior area that records the head- and thoracic-appendage backstrokes against the substrate. The posterior area shows chevron-like markings or small subcircular impressions that record the abdominal appendages of the animal, also ending in a thin, straight, terminal extension. Specimens display lateral repetition, and are commonly grouped into twos or threes with a fix point at the posteriormost tail-like structure. T. ottawensis is interpreted as a jumping structure, probably in connection with feeding purposes. The two ichnospecies occur in close association, and share sufficient morphologic features to support the same type of arthropod producer. T. buildexensis closely mimics the ventral anatomy of the tracemaker, whereas T. ottawensis records the jumping abilities of the animal providing significant ethologic and paleoecologic information. The presence of well-differentiated cephalic, thoracic, and abdominal features, particularly in T. buildexensis, resembles the diagnostic tagmosis and segmentation of insects. Detailed analysis of trace morphology and comparison with described Paleozoic insect fossils and extant related forms suggest a monuran as the most likely tracemaker.     

The importance of highly unsaturated fatty acids in zooplankton nutrition: evidence from experiments with Daphnia, a cyanobacterium and lipid emulsions

1. We used laboratory growth and feeding experiments to evaluate the role of ω3 highly unsaturated fatty acids (HUFA) in zooplankton nutrition. Polyunsaturated fatty acids (PUFA) comprised 40% of total fatty acids (FA) in the green alga Scenedesmus acutus but only 6% in the cyanobacterium Synechococcus elongatus.Scenedesmus contained modest amounts of the ω3 HUFA eicosapentaenoic acid (EPA, 20 : 5ω3) and docosahexaenoic acid (DHA, 22 : 6ω3), whereas Synechococcus contained only a trace of EPA and no DHA. 2. One-day-old Daphnia maintained high growth rates for 2–3 days on a diet of Synechococcus but exhibited reduced growth or even lost weight over the later part of the 6- or 7-day experiments. Daphnia magna grew better than D. galeata or D. pulicaria on a diet of pure Synechococcus. Daphnids fed the same concentration (0.5 mgC l^–1) of green algae or a mixture of green algae and Synechococcus maintained high growth rates. 3. Supplementing Synechococcus with fish oil emulsions rich in ω3 HUFA markedly improved the growth and reproduction of all three Daphnia species. Supplementation with an emulsion of monounsaturated oleic acid (18 : 1ω9), however, did not affect the growth of D. galeata and caused a decrease in the growth of D. magna. 4. Short-term (7 min) and long-term (3 h) feeding trials with ¹⁴C-labelled Synechococcus were used to evaluate the effects of acclimation and mixed diets on carbon incorporation. D. galeata that had fed on unlabelled Synechococcus for 3 days exhibited no decline in clearance rate but a marked decline in carbon incorporation in comparison with animals acclimated with Scenedesmus or fed a mixture of Synechococcus and Scenedesmus. 5. Our results support the hypothesis that the poor nutritional quality of a cyanobacterium is at least partially due to a HUFA deficiency. Growth and feeding experiments both suggest that the utilization of Synechococcus is enhanced by HUFA from lipid reserves or a mixed diet.     

Influence of ultraviolet-B radiation on the drift response of stream invertebrates

1. Recent studies have shown that ultraviolet (UV) radiation (280–400 nm) has increased by ≈ 8% in temperate regions over the past decade, but little effort has been devoted to understanding the ecological effects on temperate ecosystems. This research examined the effects of artificial ultraviolet-B (UVB; 280–320 nm) radiation on the drift response of immature stream insects in laboratory microcosms.
2. Two experiments involved natural populations of stream invertebrates, collected from the Cache la Poudre River (September 1994) and the Arkansas River (October 1995) in Colorado. UVB lamps were turned on from 10.00 to 14.00 h each day, and drifting animals were collected on days 1, 3, 5 and 7 during the exposure period. Levels of artificial UVB used in these experiments were similar to levels that stream organisms experience during clear, mid-day conditions at Fort Collins, Colorado (longitude 105°30'; latitude 40°35').
3. Drift was significantly higher in microcosms exposed to UVB than in controls and was dominated by Baetis sp. (Ephemeroptera: Baetidae), Trichoptera (caddisflies) and Simulium sp. (Diptera: Simuliidae). The increased drift of some stream invertebrates in UVB-exposed streams may be a behavioural response and/or a result of injury.
4. Stream organisms may be particularly sensitive to predicted increases in UV radiation, because streams are generally shallow with clear water. As a result of this potential sensitivity, we recommend that research be directed to understanding the ecological effects of UV radiation on these habitats.