Bottled Mineral Waters Polluted by Protozoa in Mexico

A survey of protozoa polluting bottled mineral water in Mexico was carried out using samples obtained from the three best-selling brands of bottled mineral water in the country. The organisms were concentrated through filtration procedures and subsequently cultured in sterile media. The cultures were observed over four weeks, with identification to the level of genus and species. Most commonly found were the amoebae Naegleria gruberi, Acanthamoeba astronyxis, and Vahlkampfia vahlkampfi (trophic as well as cystic stages) plus one flagellate, Bodomorpha minima. No ciliates were detected. The public health importance of the findings is obvious, since some strains of Naegleria and Acanthamoeba have the potential to cause human disease that may lead to death.     

Estimating consumable biomass from body length and order in insects and spiders

1. Current models used to estimate insect prey biomass for diet studies use whole weight. However, a large proportion of an arthropod's body is taken up by an indigestible exoskeleton, leading to erroneous estimation of the food intake of insectivorous animals. 2. Linear mixed effect models were used to obtain equations to predict consumable biomass from body length for a variety of Neotropical insects and spiders. These data were obtained by feeding taxa of various orders to groups of 100 social spiders and comparing pre‐ and post‐consumption weights using size‐matched controls. 3. Significant linear relationships were found relating body size to consumed biomass for all orders, with slopes ranging from 1.276 to 4.011 and R² values from 0.476 to 0.929. For orders other than spiders and Orthoptera, the increase in weight with size exhibited negative allometric scaling, suggesting a decrease in tissue density, or an increase in internal air space, with size. 4. Although there were significant differences across taxonomic orders in the proportion of biomass consumed, within most orders the proportion consumed did not differ significantly with body size. The estimated regression coefficients may be used by other workers to estimate consumable biomass of arthropod prey for studies requiring large sample sizes or non‐lethal sampling of rare or endangered species.     

Separation and partial characterization of chloroplast and cytoplasmic ribosomes from Euglena gracilis

Chloroplast and cytoplasmic ribosomes from Euglena graciliswere separated by centrifugation in zonal rotors. The particleswere characterized by their sedimentation rates as well as bytheir RNA components. Total extracts from green cells contained30S, 55S and 89S particles or their aggregates, depending uponthe Mg⁺⁺ concentration. Extracts from fractions enriched forchloroplasts contained essentially 30S and 55S particles, whilethe supernatant (obtained after sedimentation of the chloroplasts)contained predominantly 89S particles or aggregates of cytoplasmicribosomes. The 30S and 55S ribosomes contained RNA componentswhich were unique and distinct from those of the cytoplasmicribosomes. We were unable to detect 70S particles from the chloroplastpreparations. Under our conditions, chloroplast extracts yielded30S and 55S subunits or a series of rapidly sedimenting particles,possibly polysomes. Despite a variety of extraction techniques,we were unable to detect 70S particles from the chloroplasts. ¹This study was supported in part by grant No. HD 01787 fromthe U. S. Public Health Service. Journal paper of the New JerseyAgricultural Experiment Station (Received December 3, 1969; )     

Molecular characterization of an ancient Hepatozoon species parasitizing the 'living fossil' marsupial 'Monito del Monte' Dromiciops gliroides from Chile

The Microbiotheriid Dromiciops gliroides , also known as 'Monito del Monte', is considered to be a threatened species and the only living representative of this group of South American marsupials. During the last few years, several blood samples from specimens of 'Monito del Monte' captured at Chiloé island in Chile have been investigated for blood parasites. Inspection of blood smears detected a Hepatozoon species infecting red blood cells. The sequences of DNA fragments corresponding to small subunit ribosomal RNA gene revealed two parasitic lineages belonging to Hepatozoon genus. These parasite lineages showed a basal position with respect to Hepatozoon species infecting rodents, reptiles, and amphibians but are phylogenetically distinct from Hepatozoon species infecting the order Carnivora. In addition, the Hepatozoon lineages infecting D. gliroides are also different from those infecting other micro-mammals living in sympatry, as well as from some that have been described to infect an Australian species of bandicoot. The potential vector of this parasite appears to be the host-specific tick Ixodes neuquenensis because the sequencing of a long amplicon determined the presence of one of the two lineages found in the marsupial.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 568–576.     

Population differences in behaviour are explained by shared within‐population trait correlations

Correlations in behavioural traits across time, situation and ecological context (i.e. ‘behavioural syndromes’ or ‘personality’) have been documented for a variety of behaviours, and in diverse taxa. Perhaps the most controversial inference from the behavioural syndromes literature is that correlated behaviour may act as an evolutionary constraint and evolutionary change in one’s behaviour may necessarily involve shifts in others. We test the two predictions of this hypothesis using comparative data from eighteen populations of the socially polymorphic spider, Anelosimus studiosus (Araneae, Theriidae). First, we ask whether geographically distant populations share a common syndrome. Second, we test whether population differences in behaviour are correlated similarly to within‐population trait correlations. Our results reveal that populations separated by as much as 36° latitude shared similar syndromes. Furthermore, population differences in behaviour were correlated in the same manner as within‐population trait correlations. That is, population divergence tended to be along the same axes as within‐population covariance. Together, these results suggest a lack of evolutionary independence in the syndrome’s constituent traits.     

Nomadic behaviour and colony fission in a cooperative spider: life history evolution at the level of the colony?

The concept of colony-level life history evolution is introduced for the cooperative spiders by describing the life cycle and demography of Atbuhna binotata (Araneae: Dictynidae), a species living in groups containing up to several dozen adult females plus their offspring. In a life cycle remarkably similar to that of army ants, the colonies of A binotata were found to reproduce by fission and to alternate nomadic and sedentary phases in tight association with their internal demography. Colonies of other cooperative spiders, on the other hand, remain stationary as they grow for a number of generations before producing propagules that are relatively small subsets of the maternal colony. It is suggested that A. binotata!% peculiar life cycle may have unfolded as a consequence of the two-dimensional architecture of its nests. Expanding two-dimensional nests may fragment more easily than the three-dimensional nests characteristic of other species. A long distance group migration or nomadic phase, described here for the first time for a spider, may have followed as a mechanism to cope with potential disadvantages of fission while selecting for strict synchronization of individual life cycle stages within the nests. It is shown, however, that, as in other cooperative spiders, A. binotatd% sex ratio is also highly female biased. The theoretical implications of biased sex ratios in a species with fissioning colonies are briefly discussed.     

Encrusting patterns and life habit of Mesozoic trigonioids: a case study of Steinmanella quintucoensis (Weaver) from the Early Cretaceous of Argentina

Luci, L. 2010: Encrusting patterns and life habit of Mesozoic trigonioids: a case study of Steinmanella quintucoensis (Weaver) from the Early Cretaceous of Argentina. Lethaia, 10.1111/j.1502‐3931.2009.00210.x. Trigonioid bivalves of the genus Steinmanella Crickmay are abundant at the top of the Vaca Muerta Formation, Neuquén Basin of Argentina, of Early Valanginian age. The species Steinmanella quintucoensis (Weaver) is frequently encrusted by oysters, serpulids and mytilids. Oysters are the most conspicuous encruster, followed by serpulids and then mytilids. A taphonomic, palaeoecological and taxonomic analysis was performed on the encrusting fauna of S. quintucoensis. An analysis of encrusting preference was performed on the basis of differences in ornamentation of the host shell, which was divided in a strongly tubercled flank and a smoother ribbed corselet and escutcheon zone. A higher encrustation frequency was found for the corselet and escutcheon zone, over the larger flank. Possible explanations are differences in the sculpture of each part of the valve, closeness to the respiratory openings of the host, and relation to life position of the trigonioids. In this respect, a palaeoecological analysis of the life position of the genus Steinmanella was made on the basis of functional morphology, encrustation patterns and comparison with related fossil forms as well as living representatives, finding that the most suitable position to explain encrustation patterns and functional morphology is one with the flanks below the water–sediment interface, and the corselets exposed above the substrate. □Early Cretaceous, encrustation, Neuquén Basin, trigonioids.     

Social behaviour in a web-building lynx spider, Tapinillus sp. (Araneae: Oxyopidae)

Social behaviour involving cooperative prey capture and communal feeding is reported for the first time in the spider family Oxyopidae (lynx spiders), in a web-building species of the genus Tapinillus. This social spider inhabits communal webs that may contain several dozen individuals, including adults of both sexes and juveniles of different cohorts. Its colonies occur in clusters and appear to be long-lived, much like those of non-territorial permanently social species such as Anelosimus eximius (Theridiidae) or Agelena consociata (Agelenidae). However, unlike colonies of these other cooperative spiders, the colonies of the social Tapinillus do not have highly female-biased sex ratios. The possible explanations for this difference are discussed.