Structure, Bioadhesive Distribution and Elastic Properties of the Agglutinated Test of Astrammina rara (Protozoa: Foraminiferida)

ABSTRACT. The fine structure, elastic properties, and distribution of the fibrous, meshlike cement (bioadhesive) were studied for the test of the antarctic agglutinated foraminiferan Astrammina rara. Grain-size analysis of particles incorporated into the test compared with adjacent sediment indicates that A. rara is grain-size selective. Fractured tests curl inward, suggesting that the test is under tension—an impression substantiated by micromanipulation observations. Changes in test appearance were examined by scanning electron microscopy after sequential chemical treatments combined with ultrasonication. Organic fibrils securing fine-grained particulates on the test exterior were removed during initial sonication. A veil of fibrous organic material lining the test interior (i.e. inner organic lining) was removed by treatment with a nonionic detergent, revealing ligamentous cables of bioadhesive securely joining large grains. These cables are partially disrupted by treatment with sodium dodecyl sulfate, and further disrupted by disulfide reducing agents, suggesting that protein is an integral adhesive component. The large detrital grains incorporated into the test are arranged in an interlocked, optimally packed fashion. Together, these observations indicate that the seemingly simple spherical architecture of A. rara's test is in fact quite complex, consisting of large grains compressed by tensile cables of a proteinaceous bioadhesive, with additional rigidity supplied by fine particulate "mortar" deposited externally.     

A STUDY OF THE BACTERIA ASSOCIATED WITH THE ROOTS OF SUBTERRANEAN CLOVER AND WIMMERA RYE-GRASS

SUMMARY: A study of the bacteria from the surfaces of roots of subterranean clover ( T. subterraneum L.) and Wimmera rye-grass ( L. rigidum Gaud.) revealed that 21 genera were represented among the isolates from clover and 16 genera among those from rye-grass. Bacteria showing branched forms predominated and accounted for 63% of the 151 clover isolates and 78% of the 167 grass isolates. Most of these were identified as Arthrobacter , but from clover a significant proportion were Nocardia -like types. Members of the genera Mycoplana, Micromonospora, Mycobacterium , and Mycococcus were also identified among the branching forms.
Although the soil had been inoculated with effective rhizobia and the clover plants were effectively nodulated only one of the 318 isolates was capable of nodulating subterranean clover. The majority of the isolates were chromogenic and Gram-negative, produced acid from glucose and ammonia from peptone, were catalase-positive and grew best aerobically. Approximately half the isolates liquefied gelatin and produced hydrogen sulphide from peptone.     

Terminology used in the description of bennettitalean cuticle characters

Details of the bennettitalean stomatal apparatus, trichome bases and other cuticular features as seen in the light and scanning electron microscopes are described and an updated scheme of terminology is presented.     

The Invention of Convention

The traditional past of the people of South-West Bay, Malekula, featured a great deal of cultural borrowing. Like most Christians in Vanuatu, their negative attitude to a 'pagan' past has been changed into one of positive interest by the recent national emphasis on kastorn. Their older perception of kastorn as commodity - knowledge, rituals, objects, etc. to be bought, sold or exchanged at will - has been supplemented by the more wide- spread notion of kastom as a stable body of traditions, unshared as well as shared. The validatory potential of kastorn is being realized as people re-evaluate and reinvent their past, exploiting lacunae in customary knowledge by imaginative citation of the written ethnographic word. Contemporary needs are apparently more effectively satisfied by reference to fixed truths rather than to fluid and dynamic representations of culture.     

A signal-substrate match in the substrate-borne component of a multimodal courtship display

The environment can impose strong limitations on the efficacy of signal transmission. In particular, for vibratory communication, the signaling environment is often extremely heterogeneous at small scales. Nevertheless, natural selection is expected to select for signals well-suited for effective transmission. Here, we test for substrate-dependent signal efficacy in the wolf spider Schizocosa stridulans Stratton 1991. We first explore the transmission characteristics of this important signaling mo-dality by playing recorded substrate-bome signals through three different substrates (leaf Utter, pine litter, and red clay) and measuring the propagated signal. We found that the substrate-borne signal of S stridulans attenuates the least on leaf litter, the substrate upon which the species is naturally found. Next, by assessing mating success with artificially muted and non-muted males across different signaling substrates (leaf litter, pine litter, and sand), we explored the relationship between substrate-bome signaling and signaling substrate for mating success. We found that muted males were unsuccessful in obtaining copulations re-gardless of substrate, while mating success was dependent on the signaling substrate for non-muted males. For non-muted males, more males copulated on leaf litter than any other substrate. Taken together, these results confirm the importance of sub-strate-borne signaling in & stridulans and suggest a match between signal properties and signal efficacy - leaf litter transmits the signal most effectively and males are most successful in obtaining copulations on leaf litter.     

Allozyme analysis reveals six species within the Anopheles punctulatus complex of mosquitoes in Papua New Guinea

Abstract. Among samples collected from nineteen localities in Papua New Guinea, we have identified six species within the Anopheles punctulatus complex of mosquitoes, by means of cellulose acetate allozyme electrophoresis. An.punctulatus Dönitz sensu stricto was collected from seven villages in the Madang area and from Buksak, Sausi Mission and an area 18 km SW of Tari; An.koliensis Owen from eight villages in the Madang area, from Popondetta and Brown River near Karema; and An.farauti No. 1 from ten coastal areas including Madang, Lorengau, Popondetta, Port Moresby, Rabaul and Wewak. Three newly recognized species, reported here for the first time, are designated as An.farauti No. 4 from Gonoa and Hudini, Madang area; An.farauti No. 5 from Ketarabo near Goroka; and An.farauti No. 6 from Hiwanda near Tari. Three other known members of the complex, An.clowi Rozeboom & Knight, An.farauti No. 2 (Bryan, 1973) and An.farauti No. 3 (Mahon & Meithke, 1982) were not detected in Papua New Guinea. Problems arising with morphological characters for the identification of species in this group are discussed.