Effects of resource availability and distribution on autumn movements of the Nutcracker Nucifraga caryocatactes in the Alps

Radiotracking was used to study the ranging behaviour and movements of the Nutcracker Nucifraga caryocatactes in the Alevé forest (northwest Italian Alps), from September to December 1994-96, when Nutcrackers collected seeds of Arolla Pines Pinus cembra. Home range size and overlap decreased from September to December. Autumn ranging behaviour was not consistent with territoriality. Nutcrackers stored seeds throughout the Alevé; many apparently stored seeds in scree at high altitudes (above 2200 m) where the forest comes to an end, and also in Larch forests opposite the Alevé (probably to avoid competition with rodents and conspecifics). Estimates of Nutcracker abundance, derived from transect counts, varied significantly among habitats, years and months, which possibly reflected differences in seed availability and abundance. The ranging behaviour observed at the Alevé was compared with that monitored at Mont Avic, another area in the northwest Italian Alps, where resources (in this case Hazel Corylus avellana nuts) were concentrated in a few zones. Home range size was significantly larger at Mont Avic, especially during late autumn. There, the home range size increased and overlap decreased from September to November, when birds abandoned Hazels and dispersed to the coniferous woods. Differences between Alevé and Mont Avic implied that the availability and distribution of resources are the major determinants of the ranging behaviour of the Nutcracker during autumn. However, differences between adults and juveniles were also found.     

Effects of solar radiation on the endemic Mediterranean red alga Rissoella verruculosa: photosynthetic performance, pigment content and the activities of enzymes related to nutrient uptake

The effects of full-spectrum solar radiation and of solar radiation deprived of total u.v. radiation (λ<395 nm) on the endemic Mediterranean red alga Rissoella verruculosa (Bertoloni) J. Agardh were studied in situ in early summer, from sunrise to sunset. Photosynthetic performance, pigment content and the activities of enzymes related to nutrient uptake, were monitored under both radiation conditions throughout a daylight period.
The doses of solar radiation, measured on the day during which the experiments were carried out (24 June 1997), were 9228·25, 1109·70 and 13·03 kJ m⁻² for PAR (λ=400–700 nm), u.v.-A (λ=315–400 nm) and u.v.-B (λ=280–315 nm), respectively. Under these conditions, a clear daily variation in photosynthetic performance was found. However, no significant differences were detected between the two radiation conditions. At noon, strong sunlight impaired O₂ evolution by 75%, but complete recovery occurred during the afternoon, reaching similar values to those measured in the early morning. By contrast, photoinhibition of optimal quantum yield ( F _v/ F _m), and the relative electron transport rate was followed by only a slight recovery during the afternoon. The rate of photosynthesis in air (simulating emersion conditions), estimated by CO₂ exchange, showed a negative balance at noon, which was accentuated in plants exposed to the full-solar spectrum.
Significant changes in the activities of nitrate reductase and carbonic anhydrase were found throughout the day under both radiation conditions. In thalli receiving solar radiation deprived of u.v., total CA activity decreased throughout the day. However, in thalli exposed to full-spectrum solar radiation, the activity of the enzyme tended to increase in the afternoon, correlating with an increase in NR activity.     

Diet and food preferences of the endangered Bearded Vulture Gypaetus barbatus: a basis for their conservation

The Bearded Vulture Gypaetus barbatus population in the Pyrenees is managed using feeding stations to increase breeding success and reduce mortality in the pre-adult population. Nevertheless, very little quantitative and qualitative information has been published on such basic aspects of the species' ecology as feeding habits and dietary preferences. This study investigated both aspects through direct and unbiased observation of breeding Bearded Vultures during the chick-rearing period. Bearded Vulture diet comprises mammals (93%), birds (6%) and reptiles (1%), with medium-sized ungulates (mainly sheep/goats) the most important species in the diet (61%, n  = 677). Prey items were not selected in proportion to their availability, with the remains of larger species (cows and horses) being avoided, probably due to the variable cost/benefit ratios in handling efficiency, ingestion process and transport. There is no relationship between the proportion of sheep limbs in the diet and the proximity of feeding stations, suggesting that these sites are probably less important for breeding adults than for the pre-adult population. On the other hand, diet specificity seems related to productivity, with territories with greater trophic breadth being those with higher fecundity. Bearded Vultures prefer to eat limbs, although meat remains (provided principally by small mammals) can play an important role in guaranteeing breeding success during the first few weeks after hatching. The management of carrion provided by animals that die naturally in extensive livestock practices and the remains of wild ungulates which have died naturally or by human hunting, are important conservation tools for the Bearded Vulture and other carrion-eating species.     

Encystment in the Hypotrichous Ciliate Paraurostyla weissei: Ultrastructure and Cytochemistry1

The cyst wall of Paraurostyla weissei consists of four morphologically distinct layers. It shows an ultrastructure and composition similar to that of the previously described kinetosome-resorbing cysts, and its cytoplasm displays characteristics of “urostylid-type” cysts. Therefore it is possible to consider it a “transition ciliate” between Stichotrichina and Sporadotrichina.     

Late Pliocene and Quaternary Eurasian locust infestations in the Canary Archipelago

Meco, J., Muhs, D.R., Fontugne, M., Ramos, A.J.G., Lomoschitz, A. & Patterson, D. 2010: Late Pliocene and Quaternary Eurasian locust infestations in the Canary Archipelago. Lethaia, Vol. 44, pp. 440–454. The Canary Archipelago has long been a sensitive location to record climate changes of the past. Interbedded with its basalt lavas are marine deposits from the principal Pleistocene interglacials, as well as aeolian sands with intercalated palaeosols. The palaeosols contain African dust and innumerable relict egg pods of a temperate‐region locust (cf. Dociostaurus maroccanus Thunberg 1815 ). New ecological and stratigraphical information reveals the geological history of locust plagues (or infestations) and their palaeoclimatic significance. Here, we show that the first arrival of the plagues to the Canary Islands from Africa took place near the end of the Pliocene, ca. 3 Ma, and reappeared with immense strength during the middle Late Pleistocene preceding MIS (marine isotope stage) 11 (ca. 420 ka), MIS 5.5 (ca. 125 ka) and probably during other warm interglacials of the late Middle Pleistocene and the Late Pleistocene. During the Early Holocene, locust plagues may have coincided with a brief cool period in the current interglacial. Climatically, locust plagues on the Canaries are a link in the chain of full‐glacial arid–cold climate (calcareous dunes), early interglacial arid–sub‐humid climate (African dust inputs and locust plagues), peak interglacial warm–humid climate (marine deposits with Senegalese fauna), transitional arid–temperate climate (pedogenic calcretes), and again full‐glacial arid–cold climate (calcareous dunes) oscillations. During the principal interglacials of the Pleistocene, the Canary Islands recorded the migrations of warm Senegalese marine faunas to the north, crossing latitudes in the Euro‐African Atlantic. However, this northward marine faunal migration was preceded in the terrestrial realm by interglacial infestations of locusts. □Locust plagues, Canary Islands, Late Pliocene, Pleistocene, Holocene, palaeoclimatology.     

New data on the evolution of the Cretan spiny mouse,Acomys minous (Rodentia: Murinae), shed light on the phylogenetic relationships in the cahirinus group

The karyotype of the Cretan spiny mouse Acomys minous was examined with chromosome banding techniques in 53 individuals from 12 localities of Crete, aiming to gain a more detailed knowledge on the chromosomal constitution and variability of its natural populations. We found that it consists of three Robertsonian (Rb) populations with 2n = 38, 2n = 40 and 2n = 42, respectively, the last one being reported for the first time, and with stable fundamental number (FNa = 66, FN = 68). The G‐banding pattern proves that the Rb populations are closely linked phylogenetically by the many common Rb fusions and the lack of monobrachial homologies. In addition, they appear to freely mate at their contact areas, producing viable and fertile hybrids. No other type of chromosomal rearrangement appears to have played part in the chromosomal evolution of this species, at least in the recent past, as indicated also by the study of the telomeric sequences. Heterochromatin appears to be restricted to the pericentromeric position of all acrocentric and most biarmed autosomes, as well as of the X chromosome, whereas the Y chromosome is uniformly, yet faintly heterochromatic. Chromosome banding comparison of the karyotypes in A. minous with those of the other species in the cahirinus group (i.e. Acomys cahirinus, Acomys cilicicus, and Acomys nesiotes) proves their very close phylogenetic relationship, further reinforced by the study of the cytochrome b sequences, and that A. minous possesses the ancestral karyotype of the group. It is suggested that at least two of the karyotypes that characterize A. minous today, pre‐existed in North Africa before it colonized Crete and that the specific status of the four members in the cahirinus group may need to be revisited. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 498–509.     

The muscular system of Musellifer delamarei (Renaud-Mornant, 1968) and other chaetonotidans with implications for the phylogeny and systematization of the Paucitubulatina (Gastrotricha)

We studied comparatively the muscle organization of several gastrotrich species, aiming at shedding some light on the evolutionary relationships among the taxa of the suborder Paucitubulatina. Under confocal laser scanning microscope, the circular muscles were present in the splanchnic position as incomplete circular rings in Musellifer delamarei (Chaetonotidae) and Xenotrichula intermedia (Xenotrichulidae) and as dorsoventral bands in Xenotrichula punctata, Heteroxenotrichula squamosa and Draculiciteria tesselata (Xenotrichulidae); in the somatic position, M. delamarei shares the presence of dorsoventral muscles with all the Xenotrichulidae, in contrast with the remaining Chaetonotidae that lack these muscles. Maximum parsimony analysis of the muscular characters confirmed monophyly of Paucitubulatina and Xenotrichulidae, while the Chaetonotidae was paraphyletic, with the exclusion of Musellifer , which is the most basal genus within the Paucitubulatina. Xenotrichulidae is the sister taxon to Chaetonotidae, which in turn has Polymerurus as the most basal taxon. In general, the results agree with recent phylogenetic inferences based on molecular characters and support the hypothesis that, within Paucitubulatina, dorsoventral muscles are plesiomorphies retained in marine, interstitial, hermaphroditic gastrotrichs. Dorsoventral muscles were subsequently lost during changes in lifestyle and reproduction modality that took place with the invasion of the freshwater environment. This new information prompted us to reconsider the systematization of Chaetonotidae, proposing the establishment of Muselliferidae fam. nov. to include the genera Musellifer and Diuronotus .  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 379–398.