Does lake age affect zooplankton diversity in Mediterranean lakes and reservoirs? A case study from southern Italy

Zooplankton assemblages of 51 lacustrine environments located in the middle of the Mediterranean Region were analysed to evaluate the existence of an ‘age effect’ in determining their structure. The analysed datasets refer to two different geographic areas, one comprising 30 natural and artificial lakes in Sicily and the other an arrangement of 21 analogous aquatic ecosystems located at the bottom of the Italian Peninsula, a more pristine area called Southern Apennine region. Most of the natural lakes are of post-glacial origin. The artificial lakes in both datasets were built in the last century and offer the opportunity to evaluate the possible short-term effects of ageing on the structure of their zooplankton. A comparison of assemblages in the two regions by PERMANOVA and nMDS revealed that they are quite different; therefore they were analysed separately. An explorative analysis on the possible relationship between biological data and environmental data (including lake age) was performed on both datasets using DISTLM. The presence of an ‘age effect’ emerged only in the subset of artificial lakes of the Southern Apennine region; accordingly it was tested more in detail with an a posteriori PERMANOVA analysis in the subset of reservoirs that resulted positive in the first test. SIMPER allowed us to single out the main species responsible of changes in the zooplankton along the selected age groups. No age effect was evident in the Sicilian water bodies, where other variables, such as conductivity, trophic state, urbanisation and water level fluctuations proved to have a major role in shaping zooplankton assemblages. The results showed that the age effect is: (i) detectable only at a time scale of decades; (ii) masked by the human impact in the watershed.     

On the way from morphology to phonology: German linking elements and the role of the phonological word

German linking elements are sometimes classified as inflectional affixes, sometimes as derivational affixes, and in any case as morphological units with at least seven realisations (e.g. -s-, -es-, -(e)n-, -e-). This article seeks to show that linking elements are hybrid elements situated between morphology and phonology. On the one hand, they have a clear morphological status since they occur only within compounds (and before a very small set of suffixes) and support the listener in decoding them. On the other hand, they also have to be analysed on the phonological level, as will be shown in this article. Thus, they are marginal morphological units on the pathway to phonology (including prosodics). Although some alloforms can sometimes be considered former inflectional endings and in some cases even continue to demonstrate some inflectional behaviour (such as relatedness to gender and inflection class), they are on their way to becoming markers of ill-formed phonological words. In fact, linking elements, above all the linking -s-, which is extremely productive, help the listener decode compounds containing a bad phonological word as their first constituent, such as Geburt+s+tag ‘birthday’ or Religion+s+unterricht ‘religious education’. By marking the end of a first constituent that differs from an unmarked monopedal phonological word, the linking element aids the listener in correctly decoding and analysing the compound. German compounds are known for their length and complexity, both of which have increased over time—along with the occurrence of linking elements, especially -s-. Thus, a profound instance of language change can be observed in contemporary German, one indicating its typological shift from syllable language to word language.     

Darwin and His Pigeons. The Analogy Between Artificial and Natural Selection Revisited

The analogy between artificial selection of domestic varieties and natural selection in nature was a vital element of Darwin’s argument in his Origin of Species. Ever since, the image of breeders creating new varieties by artificial selection has served as a convincing illustration of how the theory works. In this paper I argue that we need to reconsider our understanding of Darwin’s analogy. Contrary to what is often assumed, nineteenth-century animal breeding practices constituted a highly controversial field that was fraught with difficulties. It was only with considerable effort that Darwin forged his analogy, and he only succeeded by downplaying the importance of two other breeding techniques – crossing of varieties and inbreeding – that many breeders deemed essential to obtain new varieties. Part of the explanation for Darwin’s gloss on breeding practices, I shall argue, was that the methods of his main informants, the breeders of fancy pigeons, were not representative of what went on in the breeding world at large. Darwin seems to have been eager to take the pigeon fanciers at their word, however, as it was only their methods that provided him with the perfect analogy with natural selection. Thus while his studies of domestic varieties were important for the development of the concept of natural selection, the reverse was also true: Darwin’s comprehension of breeding practices was moulded by his understanding of the working of natural selection in nature. Historical studies of domestic breeding practices in the eighteenth and nineteenth century confirm that, besides selection, the techniques of inbreeding and crossing were much more important than Darwin’s interpretation allowed for. And they still are today. This calls for a reconsideration of the pedagogic use of Darwin’s analogy too.     

Brocchi,Darwin, and Transmutation: Phylogenetics and Paleontology at the Dawn of Evolutionary Biology

Giambattista Brocchi’s (1814) monograph (see Dominici, Evo Edu Outreach, this issue, 2010) on the Tertiary fossils of the Subappenines in Italy—and their relation to the living molluscan fauna—contains a theoretical, transmutational perspective (“Brocchian transmutation”). Unlike Lamarck (1809), Brocchi saw species as discrete and fundamentally stable entities. Explicitly analogizing the births and deaths of species with those of individual organisms (“Brocchi’s analogy”), Brocchi proposed that species have inherent longevities, eventually dying of old age unless driven to extinction by external forces. As for individuals, births and deaths of species are understood to have natural causes; sequences of births and deaths of species produce genealogical lineages of descent, and faunas become increasingly modernized through time. Brocchi calculated that over 50% of his fossil species are still alive in the modern fauna. Brocchi’s work was reviewed by Horner (1816) in Edinburgh. Brocchi’s influence as a transmutational thinker is clear in Jameson’s (1827) “geological illustrations” in his fifth edition of his translation of Cuvier’s Theory of the Earth (read by his student Charles Darwin) and in the anonymous essays of 1826 and 1827 published in the Edinburgh New Philosophical Journal—which also carried a notice of Brocchi’s death in 1827. The notion that new species replace older, extinct ones—in what today would be called an explicitly phylogenetic context—permeates these essays. Herschel’s (1830) discussion of temporal replacement of species and the modernization of faunas closely mirrors these prior discussions. His book, dedicated to the search for natural causes of natural phenomena, was read by Charles Darwin while a student at Cambridge. Darwin’s work on HMS Beagle was in large measure an exploration of replacement patterns of “allied forms” of endemic species in time and in space. His earliest discussions of transmutation, in his essay February 1835, as well as the Red Notebook and the early pages of Notebook B (the latter two written in 1837 back in England), contain Brocchi’s analogy, including the idea of inherent species longevities. Darwin’s first theory of the origin of species was explicitly saltational, invoking geographic isolation as the main cause of the abrupt appearance of new species. We conclude that Darwin was testing the predicted patterns of both Brocchian and Lamarckian transmutation as early as 1832 at the outset of his work on the Beagle.     

A seafloor crater in the German Bight and its effects on the benthos

 In 1963 a deep crater was formed about 65 m below sea level in the western part of the German Bight, due to a gas eruption caused by drilling carried out from the platform ’Mr. Louie’. The study area is situated in a sandy to muddy bottom area inhabited by an Amphiura filiformis association (sensu Salzwedel et al. 1985). The crater, sometimes called ’Figge-Maar’, functions as a sediment trap, concentrating particles and organisms from the water column, thus leading to extreme sedimentation rates of about 50 cm, on average, per year. Crater stations, compared with stations situated in the vicinity, show enrichments of juveniles. Echinoderms, especially the subsurface-dwelling heart urchin Echinocardium cordatum and ophiuroids are responsive to enrichment. Other species that are typical of the Amphiura filiformis association are shown to be unable to cope with the special conditions in the crater. Received: 12 June 1998 / Accepted:16 September 1998     

Aggressive and Docile Colony Defence Patterns in Apis mellifera. A Retreater–Releaser Concept

Colony defence in Apis mellifera involves a variety of traits ranging from ‘aggressive’ (e.g. entrance guarding, recruitment of flying guards) to ‘docile’ (e.g. retreating into the nest) expression. We tested 11 colonies of three subspecies (capensis, scutellata, carnica) regarding their defensiveness. Each colony was selected as reportedly ‘aggressive’, ‘intermediate’ or ‘docile’ and consisted of about 10,000 bees. We applied three stimulation regimes (mechanical disturbance, exposure to alarm pheromones, and the combination of both) and measured their behaviours by tracking the rates of outflying bees at the entrance sites of the test hives. We provided evidence that for mechanical disturbances the test colonies resolved into two response types, if the ‘immediate’ defence response, assessed in the first minute of stimulation, was taken as a function of foraging: ‘releaser’ colonies allocated flying guards, ‘retreater’ colonies reduced the outside-hive activities. This division was observed irrespective of the subspecies membership and maintained in even roughly changing environmental conditions. However, if pheromone and mechanical stimulation were combined, the variety of colony defensiveness restricted to two further types irrespective of the subspecies membership: six of nine colonies degraded their rate of flying defenders with increasing foraging level, three of the colonies extended their ‘aggressiveness’ by increasing the defender rate with the foraging level. Such ‘super-aggressive’ colonies obviously are able to allocate two separate recruitment pools for foragers and flying defenders.     

Sound transmission and burrow characteristics of the subterranean rodentCtenomys talarum (Rodentia: Ctenomyidae)

Males of tuco-tucoCtenomys talarum Thomas, 1898 use particular burrow’s entrances to emit their territorial vocalization. Therefore we studied the internal structure of these entrances and the possible effect on the emission and propagation of airborne sounds. Externally, the burrow entrances used by tuco-tucos males to vocalize were characterized by the absence of sand mounds around their openings. Internally, most of the burrow’s entrances consisted of a main, relatively straight, tunnel of 30–40 cm length, with a diameter of 5.7–6.4 cm. After passing through the burrow’s entrance, the low-frequency components of an artificial signal played back inside the tunnel were not only less attenuated but also amplified (measured at 10–30 cm from the burrow opening). Therefore, the emission of territorial vocalizations inside the particular burrow’s entrances may be considered as a complex adaptative behavior, in which burrow structure improves the signal emission and propagation. Moreover, this work also showed thatC. talarum’s territorial vocalization seems to be adequate for long, inter-burrow communication, since its physical characteristics (high amplitude and low main frequency) are concomitant with the frequencies that are better transmitted in the natural habitat of this species of subterranean rodent.     

Change your diet or die: predator-induced shifts in insectivorous lizard feeding ecology

Animal feeding ecology and diet are influenced by the fear of predation. While the mechanistic bases for such changes are well understood, technical difficulties often prevent testing how these mechanisms interact to affect a mesopredator’s diet in natural environments. Here, we compared the insectivorous lizard Acanthodactylus beershebensis’ feeding ecology and diet between high- and low-risk environments, using focal observations, intensive trapping effort and fecal pellet analysis. To create spatial variation in predation risk, we planted “artificial trees” in a scrubland habitat that lacks natural perches, allowing avian predators to hunt for lizards in patches that were previously unavailable to them. Lizards in elevated-risk environments became less mobile but did not change their microhabitat use or temporal activity. These lizards changed their diet, consuming smaller prey and less plant material. We suggest that diet shifts were mainly because lizards from risky environments consumed prey items that required shorter handling time.     

Reversed selection responses in small populations of the housefly (Musca domestica L.)

We compared the efficacy of artificial and natural selection processes in purging the genetic load of perpetually small populations. We subjected replicate lines of the housefly (Musca domestica L.), recently derived from the wild, to artificial selection for increased mating propensity (i.e., the proportion of male–female pairs initiating copulation within 30 min) in efforts to cull out the inbreeding depression effects of long-term small population size (as determined by a selection protocol for increased assortative mating). We also maintained parallel non-selection lines for assessing the spontaneous purge of genetic load due to inbreeding alone. We thus evaluated the fitness of artificially and ‘naturally’ purging populations held at census sizes of 40 individuals over the course of 18 generations. We found that the artificially selected lines had significant increases in mating propensity (up to 46% higher from the beginning of the protocol) followed by reversed selection responses back to the initial levels, resulting in non-significant heritabilities. Nevertheless, the ‘naturally’ selected lines had significantly lower fitness overall (a 28% reduction from the beginning of the protocol), although lower effective population sizes could have contributed to this effect. We conclude that artificial selection bolstered fitness, but only in the short-term, because the inadvertent fixation of extant genetic load later resulted in pleiotropic fitness declines. Still, the short-term advantage of the selection protocol likely contributed to the success of the speciation experiment since our recently-derived housefly populations are particularly vulnerable to inbreeding depression effects on mating behavior.     

Modeling Coevolution between Language and Memory Capacity during Language Origin

Memory is essential to many cognitive tasks including language. Apart from empirical studies of memory effects on language acquisition and use, there lack sufficient evolutionary explorations on whether a high level of memory capacity is prerequisite for language and whether language origin could influence memory capacity. In line with evolutionary theories that natural selection refined language-related cognitive abilities, we advocated a coevolution scenario between language and memory capacity, which incorporated the genetic transmission of individual memory capacity, cultural transmission of idiolects, and natural and cultural selections on individual reproduction and language teaching. To illustrate the coevolution dynamics, we adopted a multi-agent computational model simulating the emergence of lexical items and simple syntax through iterated communications. Simulations showed that: along with the origin of a communal language, an initially-low memory capacity for acquired linguistic knowledge was boosted; and such coherent increase in linguistic understandability and memory capacities reflected a language-memory coevolution; and such coevolution stopped till memory capacities became sufficient for language communications. Statistical analyses revealed that the coevolution was realized mainly by natural selection based on individual communicative success in cultural transmissions. This work elaborated the biology-culture parallelism of language evolution, demonstrated the driving force of culturally-constituted factors for natural selection of individual cognitive abilities, and suggested that the degree difference in language-related cognitive abilities between humans and nonhuman animals could result from a coevolution with language.     

Chaotic dynamics of information processing: The “magic number seven plus-minus two” revisited

In a well-known collection of his essays in cognitive psychology Miller (The Psychology of Communication. Penguin, 1974) describes in detail a number of experiments aiming at a determination of the limits (if any) of the human brain in processing information. He concludes that the ‘channel capacity’ of human subjects does not exceed a few bits or that the number of categories of (one-dimensional) stimuli from which unambiguous judgment can be made are of the order of ‘seven plus or minus two’. This ‘magic number’ holds also, Miller found, for the number of random digits a person can correctly recall on a row and also the number of sentences that can be inserted inside a sentence in a natural language and still be read through without confusion. In this paper we propose a dynamical model of information processing by a self-organizing system which is based on the possible use of strange attractors as cognitive devices. It comes as an amusing surprise to find that such a model can, among other things, reproduce the ‘magic number seven plus-minus two’ and also its variance in a number of cases and provide a theoretical justification for them. This justification is based on the optimum length of a code which maximizes the dynamic storing capacity for the strings of digits constituting the set of external stimuli. This provides a mechanism for the fact that the ‘human channel’, which is so narrow and so noisy (of the order of just a few bits per second or a few bits per category) possesses the ability of squeezing or ‘compressing’ practically an unlimited number of bits per symbol—thereby giving rise to a phenomenal memory.     

Framing the ethical and legal issues of human artificial gametes in research,therapy, and assisted reproduction: A German perspective

Recent results from studies on animals suggest that functional germ cells may be generated from human pluripotent stem cells, giving rise to three possibilities: research with these so‐called artificial gametes, including fertilization experiments in vitro; their use in vivo for therapy for the treatment of human infertility; and their use in assisted reproductive technologies in vitro. While the legal, philosophical, and ethical questions associated with these possibilities have been already discussed intensively in other countries, the debate in Germany is still at its beginning. A systematic and detailed analysis of the legal framework in Germany is provided with regard to the three possibilities, including the applicable statutory laws as well as the constitutional law. The question emerges as to whether the statutory laws as well as the constitution justify a distinction to be made between embryos of artificial and natural origin. This question is subject to philosophical analysis, discussing the distinction between person and thing, dignity and price, personality and property, and nature and technique. As a result, the criterion of naturalness alone may not be sufficient to differentiate between embryos of natural and artificial origin, and other criteria need to be identified.     

Farmers’ Management of Finger Millet (Eleusine coracana L.) diversity in Tigray, Ethiopia and Implications for on-Farm Conservation

Tigray (region) is one of the major finger millet growing regions in Ethiopia and an important site from an archeobotanical point of view. Three zones of Tigray (east, central and west) were identified as representative sites in the region and a total of 14 districts/ ‘Woreda’ were surveyed. Thirty-seven landraces/farmers’ varieties of finger millet were identified/recorded. Farmers in Tigray undertake pre and post harvest selection in finger millet and sometimes they also select seeds from storage based on a number of attributes. Farmers maintain diversity as a way to ensure harvest security or stability of production, to promote diversity of diet and income sources, minimize crop failure risk, reduce insect and disease incidences and ensure efficient use of labour. The traditional management of finger millet in the entire study area is generally found to be demand driven, showing the existence of potential sites for on-farm conservation. The high morphological diversity (H =0.76 ± 0.09) found in the gene bank collections of Tigrayan origin also reveals the importance of linking ex situ with in situ conservation activities. Furthermore, the enhancement and conservation significance of the crop is discussed.     

Comparative parasitological examination on sympatric equids in the Great Gobi “B” Strictly Protected Area,Mongolia

The Przewalski’s horse (Equus caballus przewalskii) became extinct in the wild during the 1960s. Based on a successful captive breeding program, Przewalski’s horses were reintroduced to the Great Gobi Part “B” strictly protected area (SPA) in SW Mongolia in the late 1990s. The Asiatic wild ass (Equus hemionus hemionus), Przewalski’s horse, and sometimes domestic horses live sympatricly in the Gobi B SPA. Previously published data demonstrates that, as a result of their different requirements and utilization of the park’s resources, their home-range size and social structure differ. Parasitological examinations in the three equid species show how the factors “home range, social structure, and resource selection” significantly impact parasitic burden. Asiatic wild asses are potentially exposed to a higher risk of parasite re-infection due to their temporal aggregation in very large groups. This study demonstrates a highly significant greater parasite load in the Asiatic wild ass for the majority of parasites evaluated (Dictyocaulus arnfieldi, Trichostrongylus axei, Strongyloides westeri, Parascaris equorum) compared to Przewalski’s horses and domestic horses in the same habitat. Domestic horses had higher parasite loads for eggs of strongylids, eggs of anoplocephalidae, and Eimeria leuckarti. The potential risk of cross infection between sympatric living equids is high, as is the cross infection between ruminants and equids. Furthermore, this study reports for the first time the occurrence of lungworms in free-ranging Przewalski’s horses. Whereas, Asiatic wild asses and Przewalski’s horses seem to cope very well with the sometimes high parasite burden, Mongolian domestic horses manifested typical parasite burden symptoms.     

Formaldehyde stress

Formaldehyde, one of the most toxic organic compounds, is produced and processed in human cells. The level of human endogenous formaldehyde is maintained at a low concentration (0.01–0.08 mmol L⁻¹ in blood) under physiological conditions, but the concentration increases during ageing (over 65 years old). Clinical trials have shown that urine formaldehyde concentrations are significantly different between elderly Alzheimer’s patients (n=91) and normal elderly volunteers (n=38) (P<0.001). Abnormally high levels of intrinsic formaldehyde lead to dysfunction in cognition such as learning decline and memory loss. Excess extracellular and intracellular formaldehyde could induce metabolic response and abnormal modifications of cellular proteins such as hydroxymethylation and hyperphosphorylation, protein misfolding, nuclear translocation and even cell death. This cellular response called formaldehyde stress is dependent upon the concentration of formaldehyde. Chronic impairments of the brain resulted from formaldehyde stress could be one of the mechanisms involved in the process of senile dementia during ageing.     

Sources for Imanishi Kinji’s views of sociality and evolutionary outcomes

Prior to the contribution of genetics or the modern evolutionary synthesis (MES) to natural selection theory, social ecologists searched for factors in addition to natural selection that could influence species change. The idea that sociality, not just biology, was important in determining evolutionary outcomes was prevalent in research in social ecology in the 1920s and 1930s. The influence of ‘tradition’ (or the transmission of learned behaviours between generations) and the view that animals are active in selecting their own environments, rather than passive organisms acted upon by chance, were given as much attention as natural selection theory in European ecology, while animal aggregation and cooperation studies were pursued in America. Imanishi Kinji’s personal library and his scientific notes and papers reveal that he was well aware of this literature and had been profoundly influenced by these earlier viewpoints prior to writing his view of nature in his first book, Seibutsu no Sekai (The World of Living Things, 1941). Evidence is presented to show that he developed his theories based partly on early western debates in social ecology while finding inspiration and a way to express his views in the writings of philosopher Nishida Kitarō and, perhaps, General J C Smuts. One of Imanishi’s lasting contributions is in the demonstrated results of over 40 years of subsequent ecological and ethological research by Imanishi and those trained by him that maintained the broader viewpoints on evolution that had been dropped from the western corpus of research by the 1950s. The current attempt to again get beyond natural selection theory is reflected in debates surrounding genetic and cultural evolution of cooperation, the biology of ‘traditions’ and the idea of ‘culture’ in animal societies. Imanishi Kinji is the Japanese name order, with family name first. Other Japanese names in the text are also written with family name first. A modified version of this paper appeared in Japanese in Seibutsu Kagaku, Vol. 57 No. 3, April 2006, pp 142–149.     

Hybridization between two gartersnake species (<Emphasis Type="Italic">Thamnophis</Emphasis>) of conservation concern: a threat or an important natural interaction?

Distinguishing between hybrid zones formed by secondary contact versus parapatric divergence-with-gene-flow is an important challenge for understanding the interplay of geographic isolation and local adaptation in the origin of species. Similarly, distinguishing between natural hybrid zones and those that formed as a consequence of recent human activities has important conservation implications. Recent work has demonstrated the existence of a narrow hybrid zone between the plains gartersnake (Thamnophis radix) and Butler’s gartersnake (T. butleri) in the Great Lakes region of North America, raising questions about the history and conservation value of genetically admixed populations. Both taxa are of conservation concern, and it is not clear whether to regard hybridization as a threat or a natural interaction. Here we use phylogeographic and population genetic methods to assess the timescales of divergence and hybridization, and test for evidence that the hybrid zone is of recent origin. We assayed AFLP markers and ND2 mitochondrial DNA (mtDNA) sequences from T. radix, T. butleri, and the closely related short-headed gartersnake (T. brachystoma) throughout their North American ranges. We find shallow mtDNA divergence overall and high levels of variation within the contact zone. These patterns are inconsistent with recent contact of long-diverged taxa. It is not possible to distinguish true divergence-with-gene-flow from a long-term secondary contact zone, but we infer that the hybrid zone is a long-standing, natural interaction.     

Neprilysin Deficiency-Dependent Impairment of Cognitive Functions in a Mouse Model of Amyloidosis

Alzheimer’s disease, responsible for the vast majority of dementia cases in the elderly population, is caused by accumulation of toxic levels of amyloid β peptide (Aβ) in the brain. Neprilysin is a major enzyme responsible for the degradation of Aβ in vivo. We have previously shown that elevation of neprilysin levels in the brain delays the deposition of Aβ -plaques in a mouse model of amyloidosis and that lack of neprilysin leads to increased Aβ generation and to signs of incipient neurodegeneration in mouse brains. This study was designed to test whether low brain levels of neprilysin affect the amyloid pathology or perturb the learning and memory performance of mice. Double-mutated mice carrying a targeted depletion of one allele of Mme, the gene encoding neprilysin, and over-expressing human amyloid precursor protein (APP), exhibited a reinforced amyloid pathology in comparison with their APP transgenic littermates. Moreover, in contrast to their parental lines, these mice were impaired in the Morris water maze learning and memory paradigm and showed facilitated extinction in the conditioned taste aversion test. These data suggest that even a partial neprilysin deficiency, as is found during aging, exacerbates amyloid pathology and may impair cognitive functions. Special issue to Honor Dr. Akitane Mori.