The following acanthocolpid species are reported from New Caledonia. Acaenodera nautili sp. n. from Conger cinereus Rüppel differs from other Acaenodera species in details of the body-spination, the sucker-ratio and the bipartite seminal vesicle; Stephanostomum murielae sp. n. from Carangoides hedlandensis (Whitley) differs from most species of Stephanostomum in the average of 36 circum-oral spines, the circum-oral spine rows with a ventral hiatus and the anterior extent of the vitellarium being >10% of the hindbody length from ventral sucker. The species is distinguished from the three other species with these characters in a detailed review. The other species reported are: Stephanostomum aaravi Bray et Cribb, 2003 from Lethrinus miniatus and L. rubrioperculatus; Stephanostomum ditrematis (Yamaguti, 1939) from Gnathanodon speciosus; Stephanostomum japonocasum Durio et Manter, 1969 from Cephalopholis urodeta, Epinephelus areolatus, E. chlorostigma, E. maculatus, E. retouti, Lethrinus miniatus and Variola louti; Stephanostomum uku Yamaguti, 1970 and Pleorchis uku Yamaguti, 1970 from Aprion virescens.
Aphidius ervi Haliday is a parasitoid of natural populations of both Acyrthosiphon pisum (Harris) on alfalfa and Sitobion avenae (Fabricius) on wheat in Chile. In this study the performance of the aphid parasitoid on both host species was evaluated. Regardless of origin, both females and males of A. ervi were significantly smaller when reared on S. avenae than on A. pisum. Males and females of A. ervi reared on S. avenae on wheat also took significantly longer to develop than when reared on A. pisum. There was no significant difference in the sex ratio of the parasitoid when reared on these two host aphids. Survival of parasitoids from the A. pisum - alfalfa system was significantly lower when reared on S. avenae relative to those reared on A. pisum, but no significant difference in survival on both hosts was detected in parasitoids from the S. avenae - wheat system. Behaviour of parasitoid females during oviposition, such as frequency of encounters, number of attacks and stabbings of host aphids, were significantly higher in the A. pisum - A. ervi interaction than in the S. avenae - A. ervi interaction, regardless of the origin of the parasitoid. Aphid defensive reactions such as kicking or production of cornicle secretion, were significantly higher in the A. pisum - A. ervi than the S. avenae - A. ervi interaction. The results are discussed in relation to the effect of host quality and host aphid body size on parasitoid development.
The myrmecophilous isopod Platyarthrus hoffmannseggii Brandt, 1833 and the myrmecophilous springtail Cyphoderus albinus Nicolet, 1842 are commonly found in nests of a wide range of ant species in Belgium. Here we report the first record of both myrmecophiles in nests of the invasive garden ant Lasius neglectus in the Citadelpark of Ghent, Belgium. Platyarthrus hoffmannseggii was found in two of the Lasius neglectus nests studied. In one of the two C. albinus was also discovered. In the localities where the invasive garden ant Lasius neglectus was introduced, as is also the case in the Citadelpark in Ghent, it out-competes all native ant species. This ant has a dramatic effect on the local native ant fauna. However, some of the myrmecophilous species associated with the native ant-fauna are less threatened as they are accepted by this invasive garden ant.
When the nodes or links of communication networks are destroyed,
its effectiveness decreases. Thus, we must design the communication network as stable as possible, not only with respect to the initial disruption, but also with respect to the possible reconstruction of the network. A graph is considered as a modeling network, many graph theoretic parameters have been ušed to describe the stability of communication networks, including connectivity, integrity, tenacity. Several of these deal with two fundamental questions about the resulting graph. How many vertices can still communicate? How difficult is it to reconnect the graph? Stability numbers of a graph measure its durability respect to break down. The neighbour-integrity of a graph is a measure of graph vulnerability. In the neighbour-integrity, it is considered that any failure vertex effects its neighbour vertices. In this work, we define the accessible sets and accessibility number and we consider the neighbour-integrity of Generalised Petersen graphs and the relation with its accessibility number.
Lead administered to laboratory rats in drinking water (0.1-0.8 %) as lead acetate solution tends to accumulate in collagen-rich tissues such as tendons and the skin. The amount of lead deposited (and also zinc present in the tissue without its supplementation) correlates with the blood supply to the tissue investigated. The highest deposits of lead were observed in placenta and chorionic membranes, though here only about 60% are collagen-bound. No differences in the drinking habits of the animals were observed and also at lower concentrations of lead in the drinking water no dose dependence was revealed. However, at 0.8 % of lead in drinking water considerable accumulation of lead was observed in all tissues investigated.
Problems related to accuracy of tilt measurements realized during experimental studies of miniature tilt sensors (including MEMS devices) are minutely discussed. The measurements are performed by means of a custom computer controlled test rig, over the full range of pitch and roll. Accuracy of the test rig is determined in terms of uncertainty of the measurements involved. Ways of improving performance of the test rig are briefly introduced. Exemplary results of experimental works are presented. and Obsahuje seznam literatury