Ancient DNA reveals traces of Iberian Neolithic and Bronze Age lineages in modern Iberian horses

Multiple geographical regions have been proposed for the domestication of Equus caballus . It has been suggested, based on zooarchaeological and genetic analyses that wild horses from the Iberian Peninsula were involved in the process, and the overrepresentation of mitochondrial D1 cluster in modern Iberian horses supports this suggestion. To test this hypothesis, we analysed mitochondrial DNA from 22 ancient Iberian horse remains belonging to the Neolithic, the Bronze Age and the Middle Ages, against previously published sequences. Only the medieval Iberian sequence appeared in the D1 group. Neolithic and Bronze Age sequences grouped in other clusters, one of which (Lusitano group C) is exclusively represented by modern horses of Iberian origin. Moreover, Bronze Age Iberian sequences displayed the lowest nucleotide diversity values when compared with modern horses, ancient wild horses and other ancient domesticates using nonparametric bootstrapping analyses. We conclude that the excessive clustering of Bronze Age horses in the Lusitano group C, the observed nucleotide diversity and the local continuity from wild Neolithic Iberian to modern Iberian horses, could be explained by the use of local wild mares during an early Iberian domestication or restocking event, whereas the D1 group probably was introduced into Iberia in later historical times.     

Effects of brown and turbid water on piscivore–prey fish interactions along a visibility gradient

1. Environmental changes such as eutrophication and increasing inputs of humic matter (brownification) may have strong effects on predator–prey interactions in lakes through a reduction in the visual conditions affecting foraging behaviour of visually oriented predators. 2. In this experiment, we studied the effects of visual range (25–200 cm) in combination with optically deteriorating treatments (algae, clay or brown humic water) on predator–prey interactions between pike (Esox lucius) and roach (Rutilus rutilus). We measured effects on reaction distance and strike distance for pike and escape distance for roach, when pike individuals were exposed to free‐swimming roach as well as to roach held in a glass cylinder. 3. We found that reaction distance decreased with decreasing visual range caused by increasing levels of algae, clay or humic matter. The effect of reaction distance was stronger in turbid water (clay, algae) than in the brown water treatment. 4. Strike distance was neither affected by visual range nor by optical treatment, but we found shorter strike distances when pike attacked roach using visual cues only (roach held in a cylinder) compared to when pike could use multiple senses (free‐swimming roach). Escape distance for roach was longer in turbid than in brown water treatments. 5. Changes in environmental drivers, such as eutrophication and brownification, affecting the optical climate should thus have consequences for the strength of predator–prey interactions through changes in piscivore foraging efficiency and prey escape behaviour. This in turn may affect lake ecosystems through higher‐order interactions.     

The logical priority of the tree over characters and some of its consequences for taxonomy

The aim of the present paper is to explore the role of the character in phylogenetic systematics. I argue that too much emphasis is put on particular characters rather than congruence both in the choice of phylogenetic hypotheses and in taxonomic decisions. This means that the logical priority of the tree over the characters is neglected. To a large extent, this is a result of not paying enough attention to the individuality thesis which states that clades are historical individuals and hence contingent in nature.     

Development, structure and function of rhinoceros enamel

Vertical enamel prism decussation in the inner-layer enamel of rhinoceroses occurs as the result of vertical translation, in opposite senses, of zones of ameloblasts, which begins very shortly after amelogenesis commences at the enamel-dentine junction. Prisms in the centre of the decussating zones are stacked in the Pattern 3 arrangement. Zone boundary prisms adopt intermediate orientations, are locally nearly perpendicular to the enamel surface, and have a cylindrical, Pattern 1 cross-section. Decussation also continues in the outer-layer enamel, but the prisms all have occlusal-going courses: the occlusal-going zones of the inner enamel continue as the more occlusally oriented zones of the outer layer. Abrasion resistance to diamond polishing and soft abrasive projectile erosion (air-polishing with NaHCOs) and resistance to ion beam erosion is greater with distance from the nearest prism boundary discontinuity. Polished surface areas containing longitudinally sectioned prisms are more prone to 'air-polishing' and 'airbrading' erosion than areas with transversely sectioned prisms. These observed relationships fully explain the relief developed at natural wear surfaces.     

Flight endurance in relation to adult age in the green‐veined white butterfly Pieris napi

• 1 The flight apparatus in butterflies, as well as in other insects, is costly to manufacture. Since most animals live in a world where resources are limited, trade‐offs are expected and available resources must thus be allocated between flight and other functions, such as reproduction.
• 2 To mitigate this trade‐off, previous studies have shown that butterflies can break down flight muscles in the thorax as they age in order to use muscle nutrients for reproduction.
• 3 Although breakdown of flight muscles is expected to reduce flight ability, relative flight muscle mass (thorax mass/body mass) in many butterfly species does not decrease with age. The aim of the present study was to test the relationship between flight endurance and adult age in the green‐veined white butterfly Pieris napi (L.). The tests were performed in the laboratory at five different temperatures.
• 4 The results showed that age has a significant influence on butterfly flight endurance; older butterflies showed reduced flight endurance. Male butterflies fly for a longer time than females and flight endurance increases with temperature in both sexes.

     

Weak responses to dietary enrichment in a specialized aphid predator

Some ladybeetles are specialist predators of aphids, coccids or other prey, although they often eat a variety of species from their focal prey taxon. In addition, the diet is often supplemented with alternative prey. How larvae of the aphidophagous Coccinella septempunctata L. utilize a non‐aphid alternative prey (fruit‐fly larvae Drosophila melonogaster Meigen) is compared with adequate (i.e. high‐quality) aphid prey provided alone (monotypic diet) or in mixed diets. The alternative prey are presented either nutrient‐enriched (i.e. raised on dog food supplemented medium) or not (raised on pure medium). Ladybird performance (survival, growth and development) is poor on the pure fly larvae diets, and also reduced when given mixed diets compared with the pure aphid diet. Nutrient enrichment of the fly larvae has no positive effects. The physiological background for the differences in food value, as indicated by performance in life‐history parameters, is a strong pre‐ingestive effect (i.e. reduced consumption of fly larvae compared with aphids) and a post‐ingestive effect (i.e. reduced utilization of assimilated larval fly tissue), whereas the assimilation efficiency of the consumed fly larvae is as high as that of aphids. The results show a physiological trade‐off resulting from prey specialization that reduces the possibility of utilizing alternative prey when the availability of aphids is scarce. Connected with this is a high robustness against variation in prey nutrient diversity and composition; the ladybird shows little positive response to dietary mixing (i.e. neither mixing of adequate aphids, nor of aphids and alternative prey) or to nutrient enrichment of prey. This contrasts with the results from generalist predators (spiders), where similar treatments lead to strong effects on life‐history parameters.     

THE FIRST NEOCERATOPSIAN DINOSAUR REMAINS FROM EUROPE

Abstract:  Shallow marine, nearshore strata of earliest Campanian ( Gonioteuthis granulataquadrata belemnite Zone) and latest Early Campanian (informal Belemnellocamax mammillatus belemnite zone) age in the Kristianstad Basin, southern Sweden, have yielded isolated leptoceratopsid teeth and vertebrae, representing the first record of horned dinosaurs from Europe. The new leptoceratopsid occurrence may support a European dispersal route for the Leptoceratopsidae, or may represent an entirely endemic population. The presence of leptoceratopsid teeth in shallow marine deposits contradicts previous hypotheses suggesting that basal neoceratopsians mainly preferred arid and/or semi-arid habitats far from coastal areas.