Livestock density affects species richness and community composition of butterflies: A nationwide study

Extensively managed grasslands are globally recognized for their high biodiversity value. Over the past century, a continuous loss and degradation of grassland habitats has been observed across Europe that is mainly attributable to agricultural intensification and land abandonment. Particularly insects have suffered from the loss of grassland habitats due to land-use change and the decrease in habitat quality, either due to an increase in livestock density, higher mowing frequency, and an increase in nitrogen fertilization, or by abandonment. However, only a few studies have used nationwide datasets to analyse the effects of land cover and land-use intensity on insects. It further remains largely unexplored how these effects are modulated by species traits, i.e. habitat specialisation and mobility. Using nationwide butterfly data originating from the German Butterfly Monitoring Scheme, we investigated the effect of three indicators related to land cover and agricultural land-use intensity on species richness as well as trait composition of butterfly communities. Based on agricultural census data at the municipality scale, we calculated the share of permanent grasslands (measure of habitat availability), the total livestock density (proxy for organic fertilization) and the livestock density of domestic herbivores (proxy for management intensity in grasslands) within a 2 km buffer surrounding each butterfly transect. To analyse the relationships between butterflies and indicators of land cover and land-use intensity, we applied generalised linear mixed effect models. We found a negative relationship between butterfly species richness and the livestock density of domestic herbivores. Further, the ratio of butterfly generalist to specialist species shifted towards generalists and the size of butterflies increased with higher herbivore livestock density, indicating a shift in communities towards mobile habitat generalists. Our results are in accordance with previous studies carried out across smaller geographic extents, highlighting the importance of low herbivore livestock densities to halt the loss of pollinating insects and safeguard biodiversity and associated ecosystem services in agricultural landscapes. We here demonstrate that indicators based on livestock distribution data at the municipality scale can provide insights into processes and spatial diversity patterns of butterflies at the national level. Further, we highlight potentials and limitations of using agricultural census data to quantify and assess effects of land cover and land-use intensity on butterflies, and make recommendations for further research needs.

Intensive grazing alters the diversity, composition and structure of plant-pollinator interaction networks in Central European grasslands

Complex socio-economic, political and demographic factors have driven the increased conversion of Europe's semi-natural grasslands to intensive pastures. This trend is particularly strong in some of the most biodiverse regions of the continent, such as Central and Eastern Europe. Intensive grazing is known to decrease species diversity and alter the composition of plant and insect communities. Comparatively little is known, however, about how intensive grazing influences plant functional traits related to pollination and the structure of plant-pollinator interactions. In traditional hay meadows and intensive pastures in Central Europe, we contrasted the taxonomic and functional group diversity and composition, the structure of plant-pollinator interactions and the roles of individual species in networks. We found mostly lower taxonomic and functional diversity of plants and insects in intensive pastures, as well as strong compositional differences among the two grassland management types. Intensive pastures were dominated by a single plant with a specialized flower structure that is only accessible to a few pollinator groups. As a result, intensive pastures have lower diversity and specificity of interactions, higher amount of resource overlap, more uniform interaction strength and lower network modularity. These findings stand in contrast to studies in which plants with more generalized flower traits dominated pastures. Our results thus highlight the importance of the functional traits of dominant species in mediating the consequences of intensive pasture management on plant-pollinator networks. These findings could further contribute to strategies aimed at mitigating the impact of intensive grazing on plant and pollinator communities.

Effects of Natura 2000 on nontarget bird and butterfly species based on citizen science data

The European Union's Natura 2000 (N2000) is among the largest international networks of protected areas. One of its aims is to secure the status of a predetermined set of (targeted) bird and butterfly species. However, nontarget species may also benefit from N2000. We evaluated how the terrestrial component of this network affects the abundance of nontargeted, more common bird and butterfly species based on data from long-term volunteer-based monitoring programs in 9602 sites for birds and 2001 sites for butterflies. In almost half of the 155 bird species assessed, and particularly among woodland specialists, abundance increased (slope estimates ranged from 0.101 [SD 0.042] to 3.51 [SD 1.30]) as the proportion of landscape covered by N2000 sites increased. This positive relationship existed for 27 of the 104 butterfly species (estimates ranged from 0.382 [SD 0.163] to 4.28 [SD 0.768]), although most butterflies were generalists. For most species, when land-cover covariates were accounted for these positive relationships were not evident, meaning land cover may be a determinant of positive effects of the N2000 network. The increase in abundance as N2000 coverage increased correlated with the specialization index for birds, but not for butterflies. Although the N2000 network supports high abundance of a large spectrum of species, the low number of specialist butterflies with a positive association with the N2000 network shows the need to improve the habitat quality of N2000 sites that could harbor open-land butterfly specialists. For a better understanding of the processes involved, we advocate for standardized collection of data at N2000 sites.

[Enlarged blind spot and reduced visual evoked potentials due to melanocytoma of the optic disc]

A 59-year-old male patient presented with clinical characteristics of a melanocytoma of the optic disc in the right eye. Using functional tests, such as visual acuity, visual fields, visual evoked potentials (VEP) and imaging procedures (e.g., fundus photography and spectral domain optical coherence tomography) the findings were documented. Best corrected visual acuity was 25/20 in both eyes. Ophthalmoscopy showed a slightly prominent and pigmented tumor in the upper third of the optic disc. Comparing both eyes, an enlarged blind spot and a reduction of VEP were detectable.

In vivo synthesis of meganuclease for generating transgenic zebrafish Danio rerio

The authors show that co-injection at the one-cell stage of mRNA encoding a nuclear-targeted meganuclease I-SceI together with expression cassettes flanked by cognate restriction sites results in efficient stable transgenesis in zebrafish Danio rerio.

Comparison of the effects of simmondsin and cholecystokinin on metabolism, brown adipose tissue and the pancreas in food-restricted rats

In this study, we investigated the analogies between the physiological effects of simmondsin, a satiety-inducing glycoside extracted from jojoba seeds, and the gastro-intestinal satiation peptide, cholecystokinin. The effects of intraperitoneal injection of the biological active CCK-octapeptide on the pancreas, interscapular brown adipose tissue, growth performance and energy metabolism in normal-fed, severely food intake-restricted (50 % of normal food intake) or moderately food intake-restricted (65 % of normal food intake) growing rats were compared to the effects of 0.25 % simmondsin mixed in the food, inducing moderate food intake reduction (65 % of normal) in rats. Cholecystokinin induced pancreatic hypertrophy. In normal fed rats, cholecystokinin had no effect on brown adipose tissue or growth, while, in severely food intake-restricted rats, it caused brown adipose tissue hypertrophy and reduced growth. In moderately food intake-restricted rats, both cholecystokinin and simmondsin induced pancreatic hypertrophy, increased brown adipose weight and metabolism and caused a slight decrease in growth. We conclude that cholecystokinin may decrease growth performance in fast growing severely food intake-restricted rats by stimulating brown adipose tissue metabolism, probably because of protein shortage induced by pancreatic hyperstimulation. Simmondsin has similar effects. These results support the hypothesis that endogenous cholecystokinin is involved in the effects of simmondsin in rats.

Reproductive performance of rats treated with defatted jojoba meal or simmondsin before or during gestation

The effects on food intake, growth and reproductive performance parameters of defatted jojoba meal and pure simmondsin, an extract from jojoba meal, were compared in female Wistar rats. Rats fed 0.15% simmondsin or 3% defatted jojoba meal (equivalent to 0.15% simmondsin) for 8 weeks before conception showed a similar reduction in food intake (about 20%) and a similar growth retardation compared with controls. Both treatments induced a reduction in the number of corpora lutea on gestation day 16: this effect could be ascribed to the lower food intake before conception because it was also observed in rats pair-fed to the treated ones. Rats given feed containing 0.15% simmondsin or 3% defatted jojoba meal during days 1-16 of gestation showed a similar reduction in food intake relative to controls. Foetal and placental weights were reduced, relative to controls, to a similar extent in both groups, and the reductions were slightly greater than in the corresponding pair-fed groups. We conclude that the effects on food intake, growth and reproductive performance that were seen after feeding rats defatted jojoba meal were due to the simmondsin content of the meal. The simmondsin induced reduction in food intake and probably also a relative protein shortage.

Devazepide reverses the anorexic effect of simmondsin in the rat

Simmondsin, a glycoside extracted from jojoba meal (Simmondsia chinensis), causes a reduction in food intake after oral administration. To investigate the mechanism by which simmondsin reduces food intake, fasted and free-feeding rats were given simmondsin-supplemented food and simultaneously injected with devazepide, a specific antagonist of peripheral-type cholecystokinin receptors (CCKA receptors). In free-feeding rats, supplementation of food with 0.5% simmondsin caused a reduction in food intake of +/- 40% in the period of 4 h following food presentation. Intraperitoneal injection of 100 micrograms devazepide/kg body weight prevented this effect. In rats fasted for 20 h, the food intake in the 30 min after presentation of food supplemented with 0.15% or 0.50% simmondsin was reduced in a dose-related manner; this was also inhibited by simultaneous application of devazepide. It is suggested that peripheral CCKA receptors are involved in the effect of simmondsin on food intake. However, a direct effect of simmondsin on CCKA receptors has been excluded, since simmondsin was unable to cause contraction of the guinea-pig gallbladder in vitro.

Selenium content of livers from sex-linked dwarf and normal broiler breeders. Influence of a thyrotropin-releasing hormone-induced growth hormone release

Plasma concentrations of cGH, T3, and T4 were not different between dwarf and normal broiler breeders. Normal hens had a liver selenium content of 710 +/- 35 ng/g, and dwarf hens 656 +/- nine ng/g (n = 8). Following injections into a wing vein of different doses (1.5, 3, 6, 12, and 24 micrograms/kg) of the hypothalamic hormone TRH, GH was increased after 15 min. This effect seemed to last longer in dwarf chickens. Plasma concentrations of T3 increased significantly 1 h after TRH in normal hens, but TRH was ineffective in raising T3 levels in dwarf animals. The selenium content of livers obtained following decapitation after 2 h was also increased in normal hens up to 902 +/- 42 ng/g using the highest dose of TRH (24 micrograms/kg). This seemed not to be the case for dwarf animals. A much smaller number of hepatic cGH receptors was also found in dwarf hens, whereas the affinity of the hepatic GH receptor was not influenced by the genotype. It is concluded that the sex-linked dwarf hens are unable to increase their hepatic T4 into T3 conversion following a TRH challenge probably because of a deficiency in hepatic GH receptors. The lower content of selenium in dwarfs and their inability to increase its uptake after TRH seem therefore to support the hypothesis that selenium has a direct role in the activity of the 5'-deiodinase complex.

Effects of dietary T3 on growth parameters and hormone levels in normal and sex-linked dwarf chickens

Tri-iodothyronine (T3) has been administered in the diet, from day of hatch until 8 weeks of age, to sex-linked dwarf and normal chicks of both sexes from a brown-egg slow-growing strain. Feed was supplemented with either 0.1 ppm or 0.5 ppm T3. A significant genotype by treatment interaction was observed on body weight: the effect of T3 in males was significantly positive for dwarfs and null for normals, the effect in females was null for dwarfs and significantly negative for normals. Feed efficiency was rather decreased by the treatment in both genotypes. Abdominal fatness was decreased in a dose-dependent manner in both genotypes, while rectal temperature was raised in dwarf chicks only. Plasma T3 was raised to normal levels in dwarfs receiving 0.1 ppm exogenous T3, while the 0.5 ppm dose yielded hyperthyroid levels. Plasma GH levels were decreased in a dose-dependent manner by the T3 treatment, the effect being larger in dwarfs. Surprisingly, plasma IGF-I was unchanged in spite of the GH decrease, whatever the genotype or the sex. It was concluded that exogenous T3 alone can have a stimulatory effect on growth in dwarfs but can not fully restore a normal growth rate. Both T3 and IGF-I are important for a normal growth and the relationship between T3 and IGF-I production should be further investigated in order to better understand the physiological modifications due to the sex-linked dwarf gene.