Bone density and the lightweight skeletons of birds

The skeletons of birds are universally described as lightweight as a result of selection for minimizing the energy required for flight. From a functional perspective, the weight (mass) of an animal relative to its lift-generating surfaces is a key determinant of the metabolic cost of flight. The evolution of birds has been characterized by many weight-saving adaptations that are reflected in bone shape, many of which strengthen and stiffen the skeleton. Although largely unstudied in birds, the material properties of bone tissue can also contribute to bone strength and stiffness. In this study, I calculated the density of the cranium, humerus and femur in passerine birds, rodents and bats by measuring bone mass and volume using helium displacement. I found that, on average, these bones are densest in birds, followed closely by bats. As bone density increases, so do bone stiffness and strength. Both of these optimization criteria are used in the design of strong and stiff, but lightweight, manmade airframes. By analogy, increased bone density in birds and bats may reflect adaptations for maximizing bone strength and stiffness while minimizing bone mass and volume. These data suggest that both bone shape and the material properties of bone tissue have played important roles in the evolution of flight. They also reconcile the conundrum of how bird skeletons can appear to be thin and delicate, yet contribute just as much to total body mass as do the skeletons of terrestrial mammals.     

Archaeological evidence of former occurrence and changes in fishes, amphibians, birds, mammals and molluscs in the Wadden Sea area

Animal remains are well preserved in archaeological sites, especially the terp sites, of the Wadden Sea area of Denmark, Germany and The Netherlands. Here, we provide an overview on the wild mammals, birds, fishes, amphibians and molluscs found in coastal sites dating from 2700 to 2600 B.C. and 700 B.C. to A.D. 1600. Coastal people used a variety of animal species for food and other purposes. Hunting, fowling, fishing and agriculture did not have much influence on wild stocks in the period from the late Bronze Age/early Iron Age until the late Middle Ages. However, large changes to the landscape were made in the late Middle Ages by diking and damming. As a result, some species such as the northern vole (Microtus oeconomus) and the natterjack toad (Bufo calamita) disappeared from the area except for some dune districts on the islands, and others became rare, such as the grey seal (Halichoerus grypus) and the lagoon cockle (Cerastoderma lamarcki). New habitats arose for birds of dry meadows and fields, like lapwing (Vanellus vanellus) and black-tailed godwit (Limosa limosa). Sturgeon (Acipenser sturio) disappeared from the Wadden Sea within a few decades since A.D. 1890 due to the destruction of spawning grounds by damming and high exploitation pressure. Our findings are important for the ecological history of the region.     

Incidence and mechanical significance of pneumatization in the long bones of birds

The incidence of pneumatization in avian long bones was studied, by direct observation, in a large sample of species. Only proximal bones (humerus and femur) presented pneumatization in the sample studied. The incidence obtained was related to the variation of the maximum cortical thickness and mechanical properties, such as bending strength and flexural Young's modulus. Cortical thickness, bending strength and flexural Young's modulus were significantly lower in pneumatized bones than in marrow-filled bones. Furthermore, some congruence was found between pneumatization and systematic groups when compared. In this sense, Charadriformes was the only order studied with total absence of long bone pneumatization. Results on cortical thickness appear to be in agreement with modelling predictions previously made and with results obtained on other groups of flying vertebrates. The possible selective advantage of reduction in cortical thickness in relation to flying is suggested.     

Fruit size, crop mass, and plant height explain differential fruit choice of primates and birds

Seed dispersal by animals is an important ecological process shaping plant regeneration. In general, seed dispersers are highly variable and often opportunistic in their fruit choice. Despite much research, the factors that can explain patterns of fruit consumption among different animal groups remain contentious. Here, we analysed the interactions between 81 animal species feeding on the fruits of 30 plant species in Kakamega Forest, Kenya, during 840 h of observations. Our aim was to determine whether plant characteristics, fruit morphology, fruit colours and/or fruit compounds such as water, sugar, phenols and tannins explained the relative importance of fruit consumption by the two most important consumer groups, primates and birds. We found significant differences in fruit choice between both groups. Primates fed on larger fruits and on higher trees that had larger fruit crops, whereas birds were observed feeding on smaller fruits and on smaller plants producing fewer fruits. Fruit colours did not differ between fruits consumed by primates and those consumed by birds. However, differences in the fruit choice among frugivorous birds were associated with differences in fruit colours. Smaller plants with smaller fruits produced red fruits which contrasted strongly with the background; these fruits were dispersed by a distinct set of bird species. The contents of water, sugar, phenols and tannins did not differ between fruits eaten by primates and those eaten by birds. Some phylogenetic patterns were apparent; primates fed preferentially on a phylogenetically restricted subsample of large plants with large fruits of the subclass Rosidae. We discuss why the observed primate dispersal syndrome is most likely explained by a process of ecological fitting.     

Septa and processes: convergent evolution of the orbit in haplorhine primates and strigiform birds

According to the “nocturnal visual predation hypothesis” (NVPH), the convergent eyes and orbits of primates result from selection for improved stereoscopic depth perception to facilitate manual capture of prey at night. Within primates, haplorhines share additional derived orbital morphologies, including a postorbital septum and greater orbital convergence than any other mammalian clade. While the homology and function of the haplorhine septum remain controversial, experimental data suggest that septa evolved to inhibit mechanical disturbance of the orbital contents by the anterior temporalis muscle during mastication. According to this “insulation hypothesis,” haplorhines are particularly susceptible to disruption of the orbital contents because they have large and highly convergent eyes and orbits. However, comparative tests of the insulation hypothesis have been hindered by the morphological uniqueness of the haplorhine septum among mammals. Among birds, owls (Strigiformes) exhibit an expanded postorbital process that may be functionally analogous to the haplorhine septum. Here we present a comparative analysis of orbital morphology in 103 avian species that tests two hypotheses: (1) large, convergent orbits are associated with nocturnal visual predation, and (2) the strigiform postorbital process and haplorhine postorbital septum similarly function to insulate the eyes from contractions of mandibular adductors. Strigiforms, as nocturnal visual predators, possess relatively large orbits and exhibit the highest degree of orbital convergence in our sample. Notably, orbital convergence does not scale with orbit size in birds as in mammals. Owls are also unique among the birds examined in possessing extensive, plate-like postorbital processes that largely isolate the orbits from the temporal fossae. Furthermore, dissections of four owl species demonstrate that the expanded strigiform postorbital process deflects the path of mandibular adductors around the eye's inferolateral margin. These findings provide further comparative support for both the NVPH and the insulation hypothesis.     

Critical forest age thresholds for the diversity of lichens,molluscs and birds in beech (Fagus sylvatica L.) dominated forests

Forest age is one of the most simple but ecologically effective key values that may be controlled by forest management. Young and mature but managed forests differ significantly from old-growth forests in species composition, structure and socio-ecological function. Human land-use has already caused the loss or dramatic reduction in occurrence of some entire species assemblages, especially of logging-sensitive species, in Central European forests. These general statements also apply to beech forests, beech (Fagus sylvatica) being the naturally dominating tree species in Central Europe. Based on data for breeding birds (from 258 sampling plots in a sub-montane and 228 plots in a montane area), molluscs (36 plots in the sub-montane and 79 plots in the montane area) and lichens (84 plots in the montane forest), this paper aims at identifying significant forest age threshold ranges for the occurrence of these old-growth sensitive taxa. The sampling plots in the sub-montane zone (420–520 m a.s.l.) are in beech-oak forests, plots in the montane zone (650–1150 m a.s.l.) are in beech-spruce-fir forests. Stand ages in both areas range up to around 350–400 years. Threshold values for the total number of species related to stand age were calculated by recursive partitioning.In all three taxonomic groups the number of species per plot significantly increases with forest age. The same analysis was run for red-listed lichen and mollusc species as well as hole-nesting bird species. The threshold values obtained are very similar to those for the whole species assemblages, except for molluscs where considerably lower threshold values are computed with red-listed species assemblages. Regarding the confidence intervals, the difference pattern between the whole species datasets and the more sensitive species subsets is inconsistent. Threshold values in sub-montane beech forests range from 100 to 170 years and in mixed montane forests from 160 to 220 years.These threshold levels are clearly incompatible with economic interests that aim on reducing the rotation period in beech stands to less than 140 years to avoid formation of red heartwood. It would therefore seem to be essential to establish a network of trees and stands that are never logged and may thus act as areas for retreat and dispersion for logging-sensitive species.     

Wildlife trade,CITES and the protection of marine molluscs in Indonesia

ABSTRACT

Indonesia is a significant trader in marine molluscs and has a comprehensive legislative framework in place to protect and use molluscs sustainably. The recent inclusion of nautilus in Appendix II of CITES and the general lack of understanding of the level of protection and regulation Indonesia's marine molluscs receive necessitates a review of current laws and agreements. The most relevant are two legally binding international agreements, CITES and the CBD, and Law No 5, and Regulations 8 and 20, dealing with protection, preservation and exploration, respectively. Over the last 30 years, 12 species of mollusc have been legally protected in Indonesia and 7 are included in CITES Appendix II. Species that are not protected can be traded, provided quotas have been set for their commercial exploitation. Seizure data suggest that the illegal trade is considerable – on average almost 10,000 shells/year are confiscated. Seizures do not lead to prosecutions. It is recommended that (a) those involved in the trade of Indonesian marine molluscs need to familiarise themselves better with current legislation and regulation, (b) monitoring of domestic and international trade in marine molluscs needs to be better coordinated and intensified and (c) prosecutions for those trading illegally in marine molluscs need to increase.     

Common antigenic determinants in the glycoproteins of plants,molluscs and insects

An antiserum raised against -fructosidase isolated from the cell walls of suspension-cultured carrot cells cross-reacts with many plant proteins and hemocyanin ofHelix pomatia. The shared epitope appears to be a small complex glycan with a (1–2)-linked xylose residue attached to the -linked mannose residue of the core of an asparagine-linked oligosaccharide. There is strong cross-reactivity with the proteins of many seed plants, molluscs and insects, and no cross-reactivity with the proteins of fungi, algae, mosses, ferns, or any of the vertebrates tested. Xylose-containing glycans appear to increase the immunogenicity of the proteins to which they are attached, and we suggest that they may be responsible for some allergic responses of people that are repeatedly exposed to plant or insect proteins.     

The marine bivalve molluscs pathogen Vibrio neptunius produces the siderophore amphibactin,which is widespread in molluscs microbiota

Amphiphilic siderophores, including amphibactins, are the most abundant siderophores in oceans. Genes putatively encoding the amphibactin system were proposed in some bacteria and homologues of these genes are particularly abundant in multiple bacterial lineages inhabitant of low-iron seawater. However, since no defective mutant strains in any of these genes were studied to date, their role in amphibactin synthesis or uptake was not demonstrated. In this work, an in silico analysis of the genome of the mollusc pathogen Vibrio neptunius leads us to identify a gene cluster (denoted absABDEF) that is predicted to encode an amphibactin-like siderophore and several mutant strains unable to synthesize or use siderophores were constructed. The results showed that genes absABDEF are required for amphibactin synthesis. A comparative chemical analysis of V. neptunius wild type and biosynthesis mutants allowed us to identify a mixture of nine amphibactin forms produced by this bacterium. In addition, the gene abtA is predicted to encode the ferri-amphibactin outer membrane transporter. The prevalence of the amphibactin system in bivalve hemolymph microbiota was also studied. We found that the amphibactin system is widespread in hemolymph microbiota including both commensal and pathogenic bacterial species. Thus, its contribution to bacterial fitness must be more related to environmental persistence than to pathogenicity.     

Evolution of calcium-carbonate skeletons in the Hydractiniidae

Biomineralization has mostly been studied in the class Anthozoa (Phylum Cnidaria), but very little is known about the evolution of the calcified skeleton in the class Hydrozoa or about the processes leading to its formation. The evolution of the calcified skeleton is here investigated in the hydrozoan family Hydractiniidae. A phylogenetic analysis of ribosomal, mitochondrial, and nuclear-protein-coding DNA sequences supported two independent origins of the calcified skeleton within the Hydractiniidae and indicates a case of parallel evolution, as suspected in the Anthozoa. Neither of the two origins of skeleton in the Hydractiniidae has led to either speciose or numerically abundant species, in contrast with other skeletonized hydrozoan families. Finally, we show that the origin of calcified skeletons in the Hydractiniidae is significantly correlated with the distribution of species with calcium carbonate granules within a polyp's gastrodermal cells. This suggests that the presence of these granules precedes the origin of a full skeleton.     

Algae-associated marine molluscs in the Azores

The raolluscan fauna of a special habitat, the high intertidal algal turf, was studied at four stations on the island of Sao Miguel, Azores. The number of species found ranged from 13 to 23. However, a small group of only six species (the bivalve Lasaea adansoni and the gastropods Pisinna punctulum, Omalogyra atomus, Fossarus ambiguus, Skeneopsis planorbis and Alvania postrema) accounted for more than 80% of all the specimens collected. Mollusc density reached values of 20000 specimens per 100 g algal dry weight. The abundance and number of species of molluscs was comparable with those reported for algal zones lower on the Azorean shores.
Wave exposure and seasonality effects were found to be small, presumably because of the relatively mild abiotic conditions and the protective role of the turf. The algal substrata influenced the phytal molluscan community in two ways. First, the abundance of molluscs was significantly correlated with algal dry weight. Secondly, molluscan abundance and diversity were influenced by the algal composition of the turf. A rich algal composition, with several species of branched fleshy and coralline algae, was associated with a rich molluscan fauna. The dominance of coralline algae resulted in a abundant but species-poor fauna, while an almost monospecific turf of Gigartina was poor in both species and number of molluscan fauna.     

Apophyses,verticiles, and denticles in skeletons of Late Paleozoic radiolarians of the subfamily Entactiniinae

Morphostructural analysis of secondary skeletal elements, such as apophyses on the main spines and verticiles on the secondary spines of certain Late Paleozoic radiolarians of the subfamily Entactiniinae allow their taxonomic rank to be raised to genus. The presence of denticles on the secondary spines is only evidence of particular species. Three skeleton morphotypes are established: primary morphotype A, verticillate morphotype B, and apophyseal morphotype C. A new species, Entactinia mariannae sp. nov., and two new genera, Apophysiacus gen. nov. with five species, A. ichikawai (Caridroit et De Wever, 1984), A. minuta (Feng, 2007), A. praepycnoclada (Nazarov et Ormiston, 1983), A. pycnoclada (Nazarov et Ormiston, 1985), and A. sakmaraensis (Kozur et Mostler, 1989), and Verticillides gen. nov. with three species, V. nazarovi nom. nov., V. nestellae sp. nov., and V. verticillatus sp. nov., are described.     

Distribution of the glio-interstitial system in molluscs

Summary Ten hamsters received repeated injections of ³H-thymidine for 4 days and were allowed to survive for 7, 28, 42 and 100 days. Changes in spatial distribution of the labelled cells and in labelling indices of each cell line in the gastric glands were studied at various days after ³H-thymidine injections, and the fate of the mucous neck cell, the replacement of the chief cell and the mode of cell migration were discussed.After 4 days of repeated injections of ³H-thymidine, the labelled parietal cells and the mucous neck cells were concentrated at the neck area. Starting from the neck area, they migrated an average of 3 micra downwards per day. By 42 days, they reached the middle level of the glands, where the labelled mucous neck cells decreased but the labelled chief cells increased in number. The differentiation of the chief cell then appears to take place at the middle level of the glands through transformation of the migratory mucous neck cells. After 4 days of the labelling, about 1.8% of the chief cells located in the lower part of the glands was found to undergo in situ replication. This indicates that the renewal of this cell type is partly assured by its own mitotic activity.The foveolar cell — the future surface epithelium — seems to migrate upwards along the long axis of the glandular tubule in the pipe line system, which means first produced, first migrates. After migrating out from the neck area, the parietal cell and the mucous neck cell (the future chief cell) take an average of 200 days to reach the lower end of the glands. In the process of migration, however, the cells produced contemporaneously at the neck area became scatteringly spread from the neck towards the bottom of the gland. The time required for the newly-formed cells to reach the lower end of the gland varied between 100 and 300 days. In the gastric glands the cells first produced at the neck area do not first reach the lower end of the glands. This mode of random migration is referred to as the stochastic flow system. As one of the probable factors which disturb the pipe line flow of downward cell migration, cellular movements perpendicular to the long axis of the glandular tubule were suggested to occur at random at an any level of the gastric glands.Supported by a Grant-in-Aid for Cancer Research from the Ministry of Education, Science and Culture, Japan     

Bonding, biophilia, biosynergy, and the future of primates in the wild

Human and nonhuman primates bond with one another in countless ways, and the results are varied and vital to the individuals and species involved. The manifesto that is the basis for the collection of essays in which this commentary is included proposes that the "human/nonhuman bonds that arise in primatological research and practice deserve and demand study and research." An essential corollary of this proposal is that the primatologists themselves must be studied. The aim of this essay is to explore the influence of human/nonhuman primate bonding on conservation practice and on the future of primates in the wild. This commentary applies the author's professional experience as a conservation psychologist and his research on the impact of profound interspecies bonds on human worldviews, attitudes, and behavior. It examines two general categories of bonds: those driven by Biophilia (human fascination with life) and those influenced by Biosynergy (mutual enrichment of life). It is the author's premise that biosynergy promotes complex collaborative interspecies bonds that broaden the conservationist's desire to enhance synergy among all organisms in an ecosystem. Conversely, biophilia induces relatively simple unidirectional bonds between humans and other animals that deepen the conservationist's desire to understand and protect certain species. This contrast raises some crucial questions. Do biophilia-driven bonds between conservationists and their favorite primates blind them to the synergistic needs of all species and impair their ability to work for sustained preservation of threatened habitat? Does biosynergy-based human/nature bonding enhance focus on conservation as an ecological science and thus ignore species-specific factors crucial to assure survival of endangered primates? How can both types of bonds be optimally applied to the conservation of wildlife and wilderness?     

Predation of birds in mist nets by callitrichids (primates): how to prevent similar events

We report predation of four birds while caught in mist nets and recommend some means of prevention. Two birds were attacked by Callitrhix jacchus and one by Saguinus midas. The predator in the fourth case was unidentified. These cases were relatively rare, affecting 0.4–4.4% of the captured birds. Two of the predated birds were caught more than 1 m above the ground and may have been accessed from branches. The other two were caught close to the ground. Reducing time intervals between net checks and cutting off branches close to nets may reduce bird predation in mist nets.