An integrative study of facultative personality calibration

The theory of facultative calibration, which explains personality differences as responses to variation in other phenotypic traits of individuals, received mixed results throughout the last years. Whereas there is strong evidence that individual differences in human behavior are correlated with the self-perception of other traits, it still needs to be questioned whether they are also adjusted to objective differences in body condition (i.e. formidability). In two independent studies (N₁?=?119 men and 124 women, N₂?=?165 men) we tested hypotheses of facultative personality calibration in an integrative way, assessing various outcomes of previous studies in the same samples (including Anger Proneness, Extraversion, Neuroticism, Narcissism, Shyness, Vengefulness, and Sociosexual Orientation). Formidability was derived from assessments of physical strength and various anthropometric measures from full-body 3D scans and paired with measures of self-perceived and other-rated physical attractiveness (based on rotating morphometric 3D body models and facial photographs). We could replicate positive correlations with self-perceived attractiveness across outcomes, though these were not corroborated by more objective assessments of attractiveness: an effect of other-rated attractiveness was clearly not supported in our results for either sex, regardless of the personality outcome. Anthropometric measures and physical strength were also largely unrelated to personality, with the exception of Extraversion, Utility of Personal Aggression, and Sociosexual Orientation. While the two samples differed in their results for domain-level Extraversion, at least the Extraversion facets Activity and Assertiveness were related to strength and masculinity in men. For Sociosexual Orientation the results of our two samples varied more substantially, a positive association was only present in Study 2. Future studies need to clarify whether formidability, potentially an indicator of genetic quality for males, enhances their orientation and success in short-term mating. Furthermore we propose longitudinal twin-difference studies as means to evaluate the theory of personality recalibration in a more controlled manner.     

Seasonal Occurrences of Epiphytic Algae on the Commercially Cultivated Red Alga Kappaphycus Alvarezii (Solieriaceae, Gigartinales, Rhodophyta)

Common problems faced in farming of the red algal genus Kappaphycus/Eucheuma are “ice-ice disease” and the occurrence of epiphytes. Considerable work has been documented on “ice-ice disease” and it's mode of infection but limited information is available on the emergence of epiphytes. The present study addresses the phenomenon of epiphyte infection, its prevalence in commercially cultivated red alga, Kappaphycus alvarezii, and their variability associated with seasonality. Cultured seaweed became susceptible to epiphytes in the dry seasons (1) between March – June and (2) September – November. Findings revealed Neosiphonia savatieri (Hariot) M. S. Kim et I. K. Lee, as the dominant infecting epiphyte, representing up to 80–85% of the epiphyte present during peak seasons. Besides N. savatieri, Neosiphonia apiculata, Ceramium sp., Acanthophora sp. and Centroceras sp. were observed in smaller quantities. SEM (Scanning Electron Microscope) micrographs revealed the epiphyte's attachment to the host. Further histological study showed the extent of penetration of epiphytes into the host's cortex tissues and condition of its surrounding tissues. The outbreak of epiphytic filamentous red algae also correlated with drastic changes in seawater temperature and salinity during March– June and September – November.     

DISTRIBUTION OF ALGAL EPIPHYTES ACROSS ENVIRONMENTAL GRADIENTS AT DIFFERENT SCALES: INTERTIDAL ELEVATION,HOST CANOPIES,AND HOST FRONDS1

Understanding epiphyte distribution in coastal communities is important because these organisms affect many others directly or indirectly. Yet, their distribution has been considerably less studied than that of their hosts and other primary‐space holders. Identifying major sources of variation in epiphyte abundance is thus still a need. Environmental gradients help predict species distribution and are pervasive on marine shores. In this study, we test the notion that environmental gradients across intertidal elevation, throughout host canopies, and along host fronds explain a large variation in the abundance of sympatric epiphytes. Our model system was the assemblage of Ascophyllum nodosum (L.) Le Jol. and its epiphytes Vertebrata lanosa (L.) T. A. Chr. [= Polysiphonia lanosa (L.) Tandy], Elachista fucicola (Velley) Aresch., and Pylaiella littoralis (L.) Kjellm. On the coast of Nova Scotia (Canada), we found evidence of a spatial segregation among these species at almost all scales. While the red epiphyte V. lanosa was more common at high‐ and midintertidal elevations (peaking at midelevations) and on middle segments of host fronds, the brown epiphytes E. fucicola and P. littoralis were more common at low elevations and restricted to distal segments of host fronds. Canopy habitat affected abundance only for V. lanosa, which was more common within the host canopy than on its periphery at midelevations. Since the studied gradients are related to predictable changes in abiotic factors, the identification of likely causes behind the observed patterns was facilitated. Our study ends by proposing abiotic and biotic factors that deserve priority in the experimental testing of the forces structuring this assemblage.     

Population dynamics of epiphytic orchids in a metapopulation context

Background and Aims

Populations of many epiphytes show a patchy distribution where clusters of plants growing on individual trees are spatially separated and may thus function as metapopulations. Seed dispersal is necessary to (re)colonize unoccupied habitats, and to transfer seeds from high- to low-competition patches. Increasing dispersal distances, however, reduces local fecundity and the probability that seeds will find a safe site outside the original patch. Thus, there is a conflict between seed survival and colonization.

Methods

Populations of three epiphytic orchids were monitored over three years in a Mexican humid montane forest and analysed with spatially averaged and with spatially explicit matrix metapopulation models. In the latter, population dynamics at the scale of the subpopulations (epiphytes on individual host trees) are based on detailed stage-structured observations of transition probabilities and trees are connected by a dispersal function.

Key Results

Population growth rates differed among trees and years. While ignoring these differences, and averaging the population matrices over trees, yields negative population growth, metapopulation models predict stable or growing populations because the trees that support growing subpopulations determine the growth of the metapopulation. Stochastic models which account for the differences among years differed only marginally from deterministic models. Population growth rates were significantly lower, and extinctions of local patches more frequent in models where higher dispersal results in reduced local fecundity compared with hypothetical models where this is not the case. The difference between the two models increased with increasing mean dispersal distance. Though recolonization events increased with dispersal distance, this could not compensate the losses due to reduced local fecundity.

Conclusions

For epiphytes, metapopulation models are useful to capture processes beyond the level of the single host tree, but local processes are equally important to understand epiphyte population dynamics.     

Diversity of dry forest epiphytes along a gradient of human disturbance in the tropical Andes

Question: Disturbance effects on dry forest epiphytes are poorly known. How are epiphytic assemblages affected by different degrees of human disturbance, and what are the driving forces? Location: An inter‐Andean dry forest landscape at 2300 m elevation in northern Ecuador. Methods: We sampled epiphytic bryophytes and vascular plants on 100 trees of Acacia macracantha in five habitats: closed‐canopy mixed and pure acacia forest (old secondary), forest edge, young semi‐closed secondary woodland, and isolated trees in grassland. Results: Total species richness in forest edge habitats and on isolated trees was significantly lower than in closed forest types. Species density of vascular epiphytes (species per tree) did not differ significantly between habitat types. Species density of bryophytes, in contrast, was significantly lower in edge habitat and on isolated trees than in closed forest. Forest edge showed greater impoverishment than semi‐closed woodland and similar floristic affinity to isolated trees and to closed forest types. Assemblages were significantly nested; habitat types with major disturbance held only subsets of the closed forest assemblages, indicating a gradual reduction in niche availability. Distance to forest had no effect on species density of epiphytes on isolated trees, but species density was closely correlated with crown closure, a measure of canopy integrity. Main conclusions: Microclimatic changes but not dispersal constraints were key determinants of epiphyte assemblages following disturbance. Epiphytic cryptogams are sensitive indicators of microclimate and human disturbance in montane dry forests. The substantial impoverishment of edge habitat underlines the need for fragmentation studies on epiphytes elsewhere in the Tropics.     

浓香型白酒窖泥中兼性厌氧细菌的分离鉴定

为探讨浓香型白酒窖泥中微生物区系的构成,采用传统微生物分类鉴定法,对泸州老窖不同窖龄窖底和窖壁泥样的可培养兼性厌氧细菌进行了分类计数,并初步鉴定到属。平板涂布法计数得出,老窖底样的菌落总数最多,达3.98×103cfu/g泥,新窖壁样菌落数最少,只有0.24×103cfu/g泥;经生理生化鉴定,参照伯杰氏细菌鉴定手册等将划线单离后的菌株归为8个属,其大部分属于芽孢杆菌属(Bacillus)和芽孢乳杆菌属(Sporolac-tobacillus),也存在假单胞菌属(Pseudomonas)、梭菌属(Clostridium)等。     

Physiological responses of the CAM epiphyte Tillandsia usneoides L. (Bromeliaceae) to variations in light and water supply

In an effort to understand the mechanisms that sustain rootless atmospheric plants, the modulation of Crassulacean acid metabolism (CAM) in response to variations in irradiance and water supply was investigated in the epiphyte Tillandsia usneoides. Plants were acclimated to three light regimes, i.e. high, intermediate and low, with integrated photon flux densities (PFD) of 14.40, 8.64 and 4.32 mol m-2 d-1 equivalent to an instantaneous PFD of 200, 100, and 50 mumol m-2 s-1, respectively. Daily watering was then withdrawn from half of the plants at each PFD for 7 d prior to sampling. In response to the three PFD treatments, chlorophyll content increased in plants acclimated to lower irradiances. Light response curves using non-invasive measurements of chlorophyll fluorescence demonstrated that photosystem II efficiency (phi PSII) was maintained in high PFD acclimated plants, as they exhibited a larger capacity for non-photochemical dissipation (NPQ) of excess light energy than low PFD acclimated plants. Net CO2 uptake increased in response to higher PFD, reflecting enhanced carboxylation capacity in terms of phosphoenolpyruvate carboxylase (PEPc) and ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) activities. After water was withdrawn, nocturnal net CO2 uptake and accumulated levels of acidity declined in all PFD treatments, concomitant with increased respiratory recycling of malate. Examining the strategies employed by epiphytes such as T. usneodies to tolerate extreme light and water regimes has demonstrated the importance of physiological mechanisms that allow flexible carboxylation capacity and continued carbon cycling to maintain photosynthetic integrity.     

Experimental confirmation of aggressive mimicry by a coral reef fish

A number of potential mimetic relationships between coral reef fishes have been described, but the underlying mechanisms are poorly understood. Similarities in colour between species have often been attributed to aggressive mimicry (where predators resemble models in order to deceive prey), however this has not been tested. The fang blenny, Plagiotremus rhinorhynchos is a specialized predator that feeds on tissues of other fishes. Some individuals appear to mimic the harmless cleaner wrasse Labroides dimidiatus in order to deceive fish visiting cleaning stations, thereby increasing access to food. In this study, the ecological relationship between the mimic and model was examined at Kimbe Bay (Papua New Guinea) and the hypothesis that colour similarities represent facultative aggressive mimicry was experimentally evaluated. Some juveniles exhibited a striking resemblance to the juvenile colouration of the cleaner wrasse, but only when in close proximity to the wrasse and only when similar in size. As predicted for mimics, P. rhinorhynchos co-occurred with L. dimidiatus, but was rare relative to the model. Among site comparisons showed that the abundance of mimetic type blennies was positively correlated with the abundance of juvenile cleaner wrasses. Approximately 50% of all P. rhinorhynchos were found 1 m from the nearest L. dimidiatus, a distance significantly shorter than expected if they were not associated. A cleaner wrasse removal experiment was carried out to test whether the colour displayed by the blenny and its foraging success were contingent upon the presence of a model. In all cases, removal of the model prompted a rapid colour change to a general non-mimetic colouration in P. rhinorhynchos. Removal of L. dimidiatus also resulted in a ~20% reduction in the average foraging success of the blenny compared to controls, supporting the hypothesis that the blenny is a facultative aggressive mimic of the cleaner wrasse.     

CULTURE STUDIES ON THE LIFE HISTORY OF CHORDARIA LINEARIS (PHAEOPHYCEAE) FROM TIERRA DEL FUEGO,SOUTH AMERICA1

Studies of laboratory cultures of Chordaria linearis (Hooker et Harvey) Cotton from southernmost South America revealed that this species has an obligate sexual life history in which a macroscopic sporophyte alternates with a monoecious microscopic gametophyte. Sexual reproduction is isogamous and under photoperiodic control. Gametes are produced only in short days, whereas in long days, asexual zoospores are formed that recycle the gametophyte generation. Unfused gametes develop into gametophytes, and sporophytes originate only from zygotes. Unlike other sexual members of the Chordariales, gametes of C. linearis have a reduced stigma and do not show phototaxis. They are released at the beginning of the night, not in the morning. In nature, C. linearis seems to be regularly infected by a dictyosiphonalean epiphyte resembling the rare arctic species Trachynema groenlandicum (Lund) Pedersen. The epiphyte is responsible for previous contradictory results obtained in laboratory cultures of C. linearis. This is the first record of Trachynema in the southern hemisphere.     

Re-terrestrialization in the phylogeny of epiphytic plant lineages: Microsoroid ferns as a case study

The fern family Polypodiaceae, with over 1600 species, is not only one of the most species-rich families of ferns, but also a major contributor to the vascular epiphytic diversity throughout the tropics. Although the vast majority of species belonging to this family prefer to grow as epiphytes, several species colonize successfully rheophytic, lithophytic, and even terrestrial habitats. Here, we explore the hypothesis that non-epiphytic habitat preferences, including terrestrial growth, evolved secondarily with epiphytes being the plesiomorphic habitat preference. The results of phylogenetic analyses, based on dense taxon sampling and four chloroplast DNA regions, were integrated with divergence time estimates and ancestral character state reconstructions to test these predictions. Both fossils and secondary calibration data were incorporated to obtain divergence time estimations. The results support the prediction of multiple transitions from epiphytic/lithophytic to terrestrial/rheophytic habitats occurring mainly in the Microsoreae lineage. The change in niche preferences coincides with niche colonization opportunities created by climatic fluctuations and geographical changes during the Oligocene and Miocene periods.