Is offspring dispersal related to male mating status? An experiment with the facultatively polygynous spotless starling

Patterns of natal dispersal are generally sex‐biased in vertebrates, i.e. female‐biased in birds and male‐biased in mammals. Interphyletic comparisons in mammals suggest that male‐biased dispersal occurs in polygynous and promiscuous species where local mate competition among males exceeds local resource competition among females. However, few studies have analysed sex‐biased patterns of dispersal at the individual level, and facultatively polygynous species might offer this opportunity. In the spotless starling, polygynous males exhibit their mating status during courtship carrying higher amounts of green plants to nests than monogamous males. We experimentally incorporated green plants to nests during four years to analyse long‐term consequences on breeding success and offspring recruitment rates. We unexpectedly found that experimental sons recruited farther than experimental daughters, while control daughters recruited farther than control sons. A similar pattern was found using observational information from eight years. We discuss this result in the context of local competition hypothesis and speculate that sons dispersed farther from nests controlled by polygynous males to avoid competition with relatives. The amount of green plants in nests affects female perception of male attractiveness and degree of polygyny, although little is known about proximate mechanisms linking this process with the offspring dispersal behaviour. Our results support the idea that male‐biased dispersal is related to polygyny in a facultatively polygynous bird.     

Is the salt marsh vegetation a determining factor in the sedimentation processes?

Many authors have referred to the important role of vegetation in the consolidation of salt marsh sediments, but experiments previously carried out by us have shown results that do not always agree with these statements. In other words, the type of salt marsh surface coverage is not the main factor that contributes to the consolidation of sediments. To test this hypothesis different Portuguese salt marsh stations (species/unvegetated areas) from two sites, Tagus estuary (Corroios and Pancas) and Ria de Aveiro (Barra and Verdemilho), were compared to evaluate their influence on suspended matter deposition on the salt marsh surface. A short-term sedimentation study was performed within stands of Spartina maritima, Halimione portulacoides, Sarcocornia perennis subsp. perennis and unvegetated areas, by analysing the deposition of sediment material on nylon filters anchored to the marsh surface. Numerical results obtained from hydrodynamic models coupled to a Lagrangean module implemented for the Ria de Aveiro and the Tagus Estuary, namely the root-mean square velocity (V _rms) and residual velocity of tides, were also used. Average sedimentation rates (mean value between the different surface cover in a salt marsh) showed a seasonal trend more or less defined but with significantly different values between sites and salt marshes. Sedimentation rates varied between marshes: there are significant differences between Pancas and the other three marshes, but only significant differences in sedimentation rates between Spartina and Sarcocornia. Despite the important role of vegetation in the consolidation of salt marsh sediments, our results suggest that, the position of stations and related abiotic conditions in the salt marshes are determining factors of variation to take into account in the studies related with the stabilization and survival of salt marshes facing sea level rise. Handling editor: P. Viaroli     

Is there a relationship between dominance rank and condition in captive male bank voles, Clethrionomys glareolus?

The sexual selection theory predicts that traits associated with male–male competition or female mate choice honestly reflects individual quality when they are costly and condition dependent. Dominance seems to be a reliable signal of male quality. The aim of this study was to investigate whether dominance rank, measured in terms of agonistic interactions and trait correlated with dominance, such as preputial gland mass, depends on condition in captive male bank voles. We used five physiological measures to characterize condition: body mass, neutrophils to lymphocytes ratio (N/L ratio), spleen mass, thymus mass and adrenal gland mass. Additionally, the condition of males was challenged with a T cell-dependent antigen, sheep red blood cells. Dominance rank was not significantly related to body mass, N/L ratio and adrenal gland mass but was positively correlated with immune defence organ mass. Moreover, testes mass was positively related to the N/L ratio. However, after Bonferroni correction, only the relationship between preputial gland mass and thymus mass remained significant. Results of this experiment showed condition dependence of dominance in captive male bank voles.     

Is the adipose fin and the lower jaw (kype) related to social dominance in male Arctic charr Salvelinus alpinus?

This study reports on the importance of the size of the kype (lower jaw) and the adipose fin for establishing and maintaining social dominance in pair-wise interactions among size-matched, reproductively active male Arctic charr Salvelinus alpinus. The size of these traits seems not to have a large influence on establishing dominance, but after 4 days of social interactions, and after dominance rank is established, subordinate males show reduced size of their adipose fins and kypes relative to that of dominant males. Consequently, these traits seem to be costly labile characters that could be of importance in inter and intra-sexual evaluations of individual quality.     

Is it possible to equilibrate the different “levels” of an imbalanced biological system by acting upon one of them only? Example of the agonistic antagonistic networks

To answer the question in the title, we take as an example the model for the regulation of agonistic antagonistic couples (MRAAC). It is a model that associates 4 non-linear differential equations and allows to simulate balance, imbalance between two state variables, and control, if necessary, by two control variables of the same nature as the state variables: this control is defined as a bilateral strategy (bipolar therapy in the medical field). The super model for the regulation of agonism antagonistic couples (SMRAAC), that may be also considered as an agonistic antagonistic network (AAN), associates several elementary MRAAC's, but the interconnection structure falls equally under the category of the agonistic antagonism (AA). First we indicate what may be the results of the interconnection, favourable or not. In the last case, a control can be performed, by acting upon a sole couple of the SMRAAC, even if other couples were imbalanced (with two AA control variables only). Simulation examples are given. We bring also a new result with the SMRAAC, i.e. the appearance of strange auractors with this model. The general models belonging to the AA phylum should put on a growing importance in the future, because they could be the sole models enable to control some complex systems by avoiding the perverse effects of the unilateral strategies.     

Is community persistence related to diversity? A test with prairie species in a long-term experiment

Community persistence, or the ability of a community to maintain species composition and diversity through time, is a component of stability that is important to restoration. We ran a biodiversity–ecosystem functioning experiment for three years, and then stopped weeding it for 5–6 years, which allowed us to test whether increased plant species diversity and dissimilarity in height would lead to increased community persistence in the face of high invasion pressure by non-native species. Our approach was unique in that the experiment varied richness (one or four species) and evenness (three levels plus monocultures of the dominant species) using two separate dissimilarity types (having all tall species or having tall and short species combined) in six spatiotemporal blocks. Persistence was quantified as to how well positive productivity–diversity relationships, proportion of planted native species, and species richness remained unchanged over time. Thus, high persistence values indicate low levels of invasion and local extinction. We found that the positive relationship between diversity measures and productivity persisted after cessation of weeding. The proportion of planted species was 32% higher in mixture than in monoculture plots, indicating that monocultures were more heavily invaded by non-native species. Reduced evenness did not affect persistence measures in plots with dissimilar heights, but measures declined linearly with decreased evenness in plots with all tall species. Our results suggest that (1) persistence–diversity relationships are likely to vary with the traits of species becoming rare and going extinct, and (2) it is important to restore higher species diversity in restoration projects to favor the long-term persistence of planted species.     

Is preoperative core biopsy accurate in determining the hormone receptor status in women with invasive breast cancer?

Background

The objective of this study was to determine the concordance rate between core needle biopsy (CNB) and surgical excision of invasive breast cancer regarding the oestrogen receptor (ER) and Progesterone receptor (PgR) status as determined by Immunohistochemistry (IHC).

Methods

Hormone receptor status was established using IHC (using quickscore system 0–8) on preoperative CNB and subsequent surgical excision in 93 patients with invasive breast cancer. Results were compared taking into account tumour's size, grade, and patient's age.

Results

The ER concordance rate between CNB and surgical excisions was 95%. The PgR concordance rate was 89%. This shows that CNB has a sensitivity of 97% for ER and 95% for PgR.There is a positive correlation of ER and PgR between CNB and surgical excision (p < 0.000001). There was no significant difference in the number of core biopsies between concordant and discordant cases.

Conclusion

Preoperative core biopsy is highly sensitive for the IHC detection of ER and PgR in invasive breast cancer. The concordance rate is higher for ER than PgR, which could be due to the fact that ER is more homogeneously distributed.

     

Is an ovulation-inducing factor (OIF) present in the seminal plasma of rabbits?

The objectives of this study were (1) to determine the effect of rabbit seminal plasma on LH secretion and ovulation using the llama animal model as an in vivo ovulation bioassay and (2) to determine the effect of llama or rabbit seminal plasma on ovulation induction in the rabbit model. In Experiment 1, llamas with a growing follicle ≥8mm in diameter were assigned randomly to one of three groups (n=5 per group) and given an intramuscular dose of 1mL of: (a) llama seminal plasma, (b) rabbit seminal plasma, or (c) phosphate buffered saline (PBS; negative control). Blood samples for LH measurement were taken every 15 min from 1.5 h before to 8 h after treatment (Day 0: starting of treatment). Llamas were examined by ultrasonography every 12h from treatment to ovulation, and then every other day until Day 16 after treatment to evaluate corpus luteum (CL) development. Blood samples for progesterone measurement were taken every other day from Day 0 to Day 16. Ovulation was detected in 4 of 5, 5 of 5, and 0 of 0 llamas treated with llama or rabbit seminal plasma and PBS, respectively (P<0.001). After treatment, plasma LH concentration increased and decreased (P<0.01) in the llama and rabbit seminal plasma group but not in the PBS-treated group. No differences were observed on CL development (P≥0.3) and progesterone secretion (P>0.05) between both seminal plasma treated groups. In Experiment 2, receptive female rabbits (n=5-7 per group) were given an intramuscular dose of: (a) 0.5, (b) 1.0 and (c) 2.0mL of either rabbit or llama seminal plasma, (d) 0.5mL PBS (negative control), or (e) 25μg of gonadoreline acetate (GnRH; positive control). Does were submitted to laparotomy 24-36 h after treatment to determine the ovulatory response and the presence of antral and hemorrhagic anovulatory follicles. Ovulation sites (7.0±0.6) were only detected in GnRH-treated does (P<0.01). There was an increase (P<0.01), in the total number of follicles (antral plus hemorraghic follicles) in those females treated with 1mL of rabbit seminal plasma and there was a tendency (P=0.08) for more hemorrhagic anovulatory follicles in does treated with 1.0 and 2.0mL of either rabbit or llama seminal plasma. Results document the presence of OIF in the seminal plasma of rabbits. The differential ovulatory response between species, however, requires further investigation.     

Is there an alternative to increasing the sample size in microarray studies?

Our answer to the question posed in the title is negative. This intentionally provocative note discusses the issue of sample size in microarray studies from several angles. We suggest that the current view of microarrays as no more than a screening tool be changed and small sample studies no longer be considered appropriate.     

Coupling the microbial food web with fish: are bacteria attached to cyanobacteria an important food source for underyearling roach?

1. After observing that juvenile roach fed intensively on cyanobacteria and that cyanobacteria were densely colonized by heterotrophic bacteria, we tested whether the bacteria are used by underyearling roach and the extent to which they contribute to the energy requirements of the fish.
2. We radiolabelled attached bacteria in a natural cyanobacterial suspension, fed the fish with these particles, and estimated their assimilation by roach. Biomass of attached bacteria on cyanobacteria increased with the proportion of the cyanobacterium Microcystis in total cyanobacteria. Biomass-specific thymidine incorporation of attached bacteria was higher than that of free bacteria.
3. In feeding experiments, we detected assimilation of bacterial biomass into muscle tissue of underyearling roach. Fish consumed Microcystis to a lesser extent compared with Aphanizomenon but assimilation of attached bacteria was higher when roach fed on Microcystis because of the higher biomass of epibacteria on this cyanobacterium. However, biomass of attached bacteria was too low to be an important food source for underyearling roach.
4. We conclude that assimilation of epibacteria from cyanobacteria cannot explain the success of roach in eutrophic lakes.     

Is the host or the parasite the most locally adapted in an amphipod-acanthocephalan relationship? A case study in a biological invasion context

Manipulative endoparasites with complex life cycles can alter their intermediate host immunity and behaviour in ways that increase survival probability within the host body cavity and enhance successful transmission to the definitive host. These parasitic manipulations are variable among and within parasite species and may result from co-evolutionary processes, in which the parasite is constrained for adaptation to the local intermediate host. Hence, arrival of a new host species in a local host population may promote local parasite maladaptation. This study tested the occurrence of local adaptation in two distantly located populations of the acanthocephalan parasite Pomphorhynchus laevis and its effect on the immunity and behaviour of its gammarid intermediate host Gammarus roeseli. This was done in France (an area for which G. roeseli is a recent invader) and Hungary (an area from which G. roeseli was believed to be native). As expected, we found no alteration in G. roeseli's immune defence and behaviour associated with infection by P. laevis in localities, where the gammarid is invasive. Unexpectedly, we found similar results in Hungarian populations, where the parasite was even more exposed to the host immune response. Whilst these results suggest maladaptation of the parasite to the gammarid in both countries, they also suggest that the gammarid host might be locally adapted to the parasite. Genetic analyses were performed on both the parasite and the host and the results suggest that the two subsets of populations we studied harbour rather isolated host-parasite systems, both probably deriving from a common ancestral population. We propose that G. roeseli is also of recent acquisition in Hungary, and that a recent co-evolutionary history between P. laevis and G. roeseli in association with a long generation time in the parasite has constrained parasite adaptations in Europe or even favoured host adaptation to the parasite.     

Is coenzyme M bound to factor F430 in methanogenic bacteria? Experiments with Methanobrevibacter ruminantium

Coenzyme M (2-mercaptoethane sulfonic acid) and factor F430 (a nickel porphinoid) are coenzymes found in methanogenic bacteria. Recently it has been proposed that in these bacteria a coenzyme MF430 also exists which plays a key role in methane formation and in which coenzyme M and F430 are bound to each other. To test this hypothesis Methanobrevibacter ruminantium, which requires coenzyme M as a vitamin, was grown in the presence of [2-14C]CoMSH. F430 and 'CoM' (mixture of CoMSH and its disulfides) were quantitatively extracted from these cells and from partially purified methyl-CoM reductase using various methods. The extracts were chromatographed on cellulose or Sephadex G-10. Under all conditions factor F430 and 'CoM' were completely (greater than 99%) separated. There was no indication for the existence of a protein-free F430 species containing covalently bound coenzyme M in Mb. ruminantium. The results support the structure previously assigned to coenzyme F430.     

Macrophytes in tropical shallow lakes: An important food item to benthic entomofauna or an underused resource?

Although macrophytes are known to increase benthic diversity in lakes, the importance of this resource as food for the insects living at the bottom of these ecosystems are still poorly understood. This study assessed the diets of benthic Chironomidae and Campsurus (Ephemeroptera) in two environments: a lake with macrophytes (M+) and another without macrophytes (M?). We expected a differential use of food resources in M+, where plant tissue is particularly important for the aquatic insects’ diet. The diet of 734 individuals from 16 taxa were analyzed. Contrary to expectations, benthic insects consumed low amounts of plant tissue. This finding led us to investigate whether the presence of macrophytes in lakes would indirectly contribute to the benthic insects’ feeding, as more food resources were explored in M+ and a spatial variation of resources intake was observed in this lake, in contrast to the homogeneous feeding in M?. We highlight that macrophytes were responsible for the organic matter build‐up in the sediment, especially at the lake region dominated by these plants, and contributed to increase the deposition of high‐quality amorphous organic matter, which favored taxa in M+ that fed exclusively on this item. The lower diversity of food items exploited in M?, and the Tanypus alga‐based diet in this lake, indicates the low quality of organic resources in its sediment. Although macrophytes were indirectly beneficial for benthic insects’ feeding, we found that this is not an attractive resource for prompt ingestion by most benthic taxa.     

Is food availability the main factor controlling the abundance of Euchlanis dilatata lucksiana Hauer in a shallow,hypertrophic lake?

Visual observations and experiments on food preference of Euchlanis dilatata lucksiana show that this euchlanid can feed on blue-green algae not consumed by the most planktonic animals. Nevertheless, even in lakes with blooms of blue-green algae, E. d. lucksiana occur infrequently and generally in low numbers. The paper is an attempt to explore into the causes for the rare occurrence of Euchlanis in the pelagial. A comparison of threshold food concentrations calculated from N and P excretion rates (Gulati et al., this volume) with the concentrations of seston in the Lake Loosdrecht shows that the latter were several times higher during study period in 1984. This implies that the food requirements of Euchlanis were always satisfied in this lake. The time needed for the consumption of the total food fraction in a liter of lake water by a concentration of 50 Euchlanis l^–1 was also calculated. This time varied from 70 to 200 days, so a Euchlanis population even at its maximum density will not cause major changes in blue-green algae biomass by grazing. Thus, food limitation cannot be viewed as a factor controlling the Euchlanis densities in Loosdrecht Lakes. There is some evidence that Euchlanis is heavily predated in Loosdrecht Lakes, losses in its biomass accounting for 126% of the production. Adaptation of this species to the littoral zone, as expressed by the deposition of eggs on plants, can also limit the occurrence of the lucksiana form to water bodies with blooms of blue-green algae.     

Expression of scatter factor/hepatocyte growth factor is regionally correlated with the initiation of sperm motility in murine male genital tract: Is scatter factor/hepatocyte growth factor involved in initiation of sperm motility?

Based upon findings that the scatter factor/hepatocyte growth factor (SF/HGF) has strong mitogenic and motogenic properties, and that the sperm cell acquires its fertilizing capacity and motility in the distal parts of mammalian epididymis, the present study was conducted to investigate the role of SF/HGF in initiation of sperm cell motility. This was investigated by determining the expression of SF/HGF in various regions of the murine male genital tract by scatter and cell tracking assays using MDCK epithelial cells, Western blot procedure, and the immunohistochemical procedure using paraffin sections of various regions of the male genital tract. The findings from all these assays indicate that SF/HGF is differentially expressed in various parts of the male genital tract with slight or no expression in the testes, caput epididymis, and vas deferens, and with the highest expression in cauda and corpus (distal) epididymis followed by expression in the corpus (proximal) epididymis. This region-specific SF/HGF expression pattern coincides with the pattern of acquiring the fertilizing capacity and motility by the sperm cell during its transit through the male genital tract. However, wherever SF/HGF was expressed in the male genital tract, its molecular weight was slightly higher (Mr, 82 kD), compared to the SF/HGF expressed in various other somatic tissues (Mr, 78 kD), indicating that the genital tract SF/HGF may be a different molecular species that shares some immunoreactive epitopes with the somatic cell SF/HGF. Incubation of immotile sperm from caput epididymis with the purified human placental SF/HGF of 78 kD initiated motility in 5–15% of sperm population. These results strongly suggest that the SF/HGF-like activity is expressed in the male genital tract in a region-specific manner, and this activity may have a role in initiation of sperm motility acquired during its transit through the epididymis in mammals. © 1994 Wiley-Liss, Inc.     

Is facial structure an honest cue to real-world dominance and fighting ability in men? A pre-registered direct replication of

Masculine facial morphology (e.g., larger jaw, prominent cheekbones) have been linked to a suite of social outcomes—including greater wealth, career progress, romantic desirability, and even greater political success. A leading explanation for these links is that dominant facial structures represent honest cues of physical dominance and fighting ability. T?ebický et al. (2013) published the first study to demonstrate that masculine facial cues (e.g., large nose, deep-set eyes) similarly predict both dominance judgments and real-world fighting success, but no studies have replicated these popular findings that a large and specific assortment of masculine facial structures are implicated in both fighting ability and dominance perception. Thus, we conducted a pre-registered direct replication and extension of T?ebický et al. (2013). Two separate samples of United States MTurk participants rated 516 UFC fighters' facial photographs on perceived aggressiveness (N = 500) and fighting ability (N = 500). Results showed that perceived aggressiveness was associated with masculine facial morphology (e.g., large nose, deep-set eyes) independent of bodily size. There was also some evidence that perceived fighting ability was associated with masculine facial morphology, which disappeared after controlling for bodily size. There was no support for the relation between facial structure and fighting success, and there were often negative relations between perceived aggressiveness and fighting ability on fighting success (i.e., more successful fighters were perceived as less successful and aggressive). We argue that our evolved psychology differentially processes the distinct avenues to victory that constitute overall fighting success (e.g., knockout versus submission wins).     

Evolutionary Trends in the Flowers of Asteridae: Is Polyandry an Alternative to Zygomorphy?

Background and Aims

Floral symmetry presents two main states in angiosperms, actinomorphy (polysymmetry or radial symmetry) and zygomorphy (monosymmetry or bilateral symmetry). Transitions from actinomorphy to zygomorphy have occurred repeatedly among flowering plants, possibly in coadaptation with specialized pollinators. In this paper, the rules controlling the evolution of floral symmetry were investigated to determine in which architectural context zygomorphy can evolve.

Methods

Floral traits potentially associated with perianth symmetry shifts in Asteridae, one of the major clades of the core eudicots, were selected: namely the perianth merism, the presence and number of spurs, and the androecium organ number. The evolution of these characters was optimized on a composite tree. Correlations between symmetry and the other morphological traits were then examined using a phylogenetic comparative method.

Key Results

The analyses reveal that the evolution of floral symmetry in Asteridae is conditioned by both androecium organ number and perianth merism and that zygomorphy is a prerequisite to the emergence of spurs.

Conclusions

The statistically significant correlation between perianth zygomorphy and oligandry suggests that the evolution of floral symmetry could be canalized by developmental or spatial constraint. Interestingly, the evolution of polyandry in an actinomorphic context appears as an alternative evolutionary pathway to zygomorphy in Asteridae. These results may be interpreted either in terms of plant–pollinator adaptation or in terms of developmental or physical constraints. The results are discussed in relation to current knowledge about the molecular bases underlying floral symmetry.Key words: Floral symmetry, architectural constraints, Asteridae, comparative analysis, composite tree, correlated evolution, evolutionary scenario