Energy reserves of parasitoids depend on honeydew from non‐hosts

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Taphonomy and palaeoecology of Hauterivian–Barremian nerineoid shell beds from the Neuquén Basin,west‐central Argentina

Nerineoid shell beds are described for the first time from Lower Cretaceous deposits of southern South America. These come from carbonates near the top of the Agrio Formation in southern Mendoza Province, west‐central Argentina. To envisage the origin of the nerineoid shell beds, a taphonomic study was carried out, which indicated that these represent within‐habitat time‐averaged, primary sedimentological concentrations with a secondary biogenic imprint related to a relatively high local production of nerineoid shells. The associated palaeoenvironments were studied through a facies analysis of the carbonate succession including the shell beds. The carbonates were deposited in a homoclinal ramp system and depict a shallowing upward trend from mid to inner ramp. The individuals lived and accumulated in oolitic shoals within the inner ramp, in a shallow, well‐lit, high‐energy setting above fair‐weather wave base. Substrate was oxygenated and loose. The nerineoids are shown to belong to one species of the genus Eunerinea, and through the functional morphology of the shells they are tentatively interpreted as infaunal or semi‐infaunal. It is suggested that the recorded monospecific nerineoid shell beds indicate that the palaeoenvironmental conditions may have been favourable for the development of abundant populations of these gastropods in the northern part of the Neuquén Basin during a short time interval in the Hauterivian–Barremian boundary. This could have been related to a brief warming episode, but other factors may have also been involved. □Argentina, Early Cretaceous, Gastropods, nerineoids, Neuquén Basin, shell beds, taphonomy.     

Semiempirical modeling of abiotic and biotic factors controlling ecosystem respiration across eddy covariance sites

In this study we examined ecosystem respiration (R_ECO) data from 104 sites belonging to FLUXNET, the global network of eddy covariance flux measurements. The goal was to identify the main factors involved in the variability of R_ECO: temporally and between sites as affected by climate, vegetation structure and plant functional type (PFT) (evergreen needleleaf, grasslands, etc.). We demonstrated that a model using only climate drivers as predictors of R_ECO failed to describe part of the temporal variability in the data and that the dependency on gross primary production (GPP) needed to be included as an additional driver of R_ECO. The maximum seasonal leaf area index (LAI_MAX) had an additional effect that explained the spatial variability of reference respiration (the respiration at reference temperature T_ref=15 °C, without stimulation introduced by photosynthetic activity and without water limitations), with a statistically significant linear relationship (r²=0.52, P<0.001, n=104) even within each PFT. Besides LAI_MAX, we found that reference respiration may be explained partially by total soil carbon content (SoilC). For undisturbed temperate and boreal forests a negative control of total nitrogen deposition (N_depo) on reference respiration was also identified. We developed a new semiempirical model incorporating abiotic factors (climate), recent productivity (daily GPP), general site productivity and canopy structure (LAI_MAX) which performed well in predicting the spatio‐temporal variability of R_ECO, explaining >70% of the variance for most vegetation types. Exceptions include tropical and Mediterranean broadleaf forests and deciduous broadleaf forests. Part of the variability in respiration that could not be described by our model may be attributed to a series of factors, including phenology in deciduous broadleaf forests and management practices in grasslands and croplands.     

New microsatellite resources for groupers (Serranidae)

We characterized nine microsatellite loci and identified an additional 60 genomic regions containing microsatellites in the red hind grouper, Epinephelus guttatus. The nine loci were highly polymorphic, and primers designed from red hind genomic DNA produced a strong amplification product in a test panel of 16 other groupers in the genera Epinephelus and Mycteroperca collected from across the world. Most of the amplified regions were homologous to the red hind locus and a well‐defined microsatellite repeat was generally evident. The nine loci, together with the 60 uncharacterized microsatellite‐containing regions, provide a powerful tool for ecological and evolutionary studies in groupers.     

Predicting the environmental niche of the genus Phymaturus: Are palluma and patagonicus groups ecologically differentiated?

The genus Phymaturus (Reptilia: Liolaemidae) is distributed in the mountains and rocky plateaux of Argentina and Chile and comprises two groups of species, palluma and patagonicus. The two lineages have diverged early in the evolution of the genus and up to today, there is very little geographical overlap between them. We worked with records of localities from the literature, herpetological collections and field data to evaluate habitat suitability of the genus Phymaturus. We used 11 environmental variables to develop environmental niche models (ENMs) for each group within the genus using the Maxent software, and to determine those variables that best explain the distribution of each group. We also estimated measures of niche similarity using ENMTools to determine whether niche differentiation is real or apparent. The geographical overlap between the groups was very low considering the large geographical range of the genus. Some variables, such as mean annual temperature, soil type and bare soil cover, have a high contribution to the models for both groups. The current niche overlap between Phymaturus groups indicates that the environmental niches of the palluma and patagonicus groups are not equivalent. Based on background analysis, we cannot reject the hypothesis that similarity (or divergence) between groups of Phymaturus is no more than expected based on the availability of habitat. The results of this study are a first approximation to the knowledge of the environmental variables associated with the palluma and patagonicus groups, and reveal that the ecological differences found between these groups are more likely due to habitat availability in their respective regions than to differences in habitat preferences.     

Two new species of Mussaenda (Rubiaceae) from Panay Island,Philippines

Two new species of Mussaenda (Rubiaceae) from Aklan, Panay, Philippines are described and illustrated. Mussaenda ustii sp. nov. is distinct by its long pedicel (up to 7 mm), yellow with white margins corolla lobes forming a star and recurved stigma lobes which are always semi‐ or distinctly exserted in long‐styled morphs. Mussaenda viridiflora sp. nov. is characterized by its white, sweet‐scented corolla lobes, which are green tinged on the median ridges and bases, and strongly reflexed calyx lobes. A discussion of the relationships of the new taxa to closely related Philippine Mussaenda is provided. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 87–92.     

Habitat requirements of the Socorro Mockingbird Mimodes graysoni

The population size of the Socorro Mockingbird Mimodes graysoni, which represents a monotypic genus endemic to Socorro Island, México, has declined dramatically within the last 40 years. Postulated causal factors include competitive exclusion by Northern Mockingbirds Mimus polyglottos, predation by feral cats and overgrazing by feral sheep. Habitat degradation looms as the primary candidate because surviving Socorro Mockingbirds live mainly in areas of the island with little apparent habitat damage, and because Northern Mockingbirds and cats both arrived on Socorro after much of the decline had occurred. Isolating key factors is difficult, however, because the present distributions of cats and Northern Mockingbirds coincide broadly with patterns of habitat degradation. To investigate habitat requirements of the endemic mockingbird in detail, we measured vegetation characteristics at localities with and without Socorro Mockingbirds, and observed their foraging behaviour. Socorro Mockingbirds occupied sites in montane regions covered with Ilex socorroensis, Guettarda insularis, Triumfetta socorrensis and Eupatorium pacificum; they were also abundant in pristine lowland forests. Socorro Mockingbirds were scarce in disturbed forests where Dodonaea viscosa has replaced the original understorey, and they were absent from low-elevation Croton masonii scrub, even in areas with no signs of degradation. Restoration of degraded habitat could help the population of Socorro Mockingbirds grow and reoccupy more of its former range.     

Landscape and anti-predation determinants of nest-site selection, nest distribution and productivity in a Mediterranean population of Long-eared Owls Asio otus

Nest predation is an important determinant of owl breeding success. We studied Long-eared Owl Asio otus productivity and attributes of nest-sites at the microhabitat and landscape scales in a Mediterranean locality over an 8-year period. We examined the effect on nest location and productivity of protective cover in concealing the nest from aerial and terrestrial predators. A dense cover of ivy and tree-foliage at canopy level favoured nest location but not productivity. By contrast, high shrub cover beneath the nest was selected by Owls and was positively related to both the site reoccupancy rate and the overall number of young fledged. Pre-fledging Owls use the ground, where they are exposed to terrestrial predators, which are much more abundant in the study area than are aerial predators. Our results therefore support the hypothesis that Owls adapt nest-site choice to local sources of predation risk. As reported elsewhere, Long-eared Owls in our study area showed restricted territoriality and nested in clusters. As active nest-sites during the same breeding season were more than 1 km apart on average, and their productivity was never greater for clustered nests than for more isolated nests, nest aggregation could not be interpreted as a case of facultative colonial breeding, which has been reported for this species in other areas. Neither landscape variables indicative of the availability of foraging areas nor structural attributes that protect young from predators explained the remarkable scarcity of nests in half of the study area. Unmeasured factors such as human disturbance could explain the pattern of distribution of Long-eared Owl nests.