Tidal rates of settlement of the intertidal barnacles Chthamalus stellatus and Chthamalus montagui in western Europe: the influence of the night/day cycle

Chthamalus montagui and Chthamalus stellatus are abundant barnacles in western Europe. Tidal settlement of Chthamalus in SW Ireland and SW Portugal was studied in relation to a night and day factor and at different temporal (dates) and spatial (shores and sites) scales. Based on the identifiable cyprids and metamorphs, Chthamalus settlement in SW Ireland was comprised mainly of C. stellatus but was composed of C. montagui only in SW Portugal.In SW Ireland and SW Portugal, settlement rates of Chthamalus (mean number of settlers per 25 cm²±S.E.) were higher after one day tidal cycle (597±158.7 in SW Ireland, 144±23.6 in SW Portugal) than one night tidal cycle (55±12.1 in SW Ireland, 13±2.2 in SW Portugal), but significant differences were only detected in SW Portugal. Different models were proposed for explaining this pattern related to night and day variability of the physical processes responsible for transporting cyprids to shore (1), and/or of pre-settlement behaviour (2) and/or of settlement behaviour of cyprids (3).Spatial patterns of tidal settlement of both species or at both locations seem similar with small scale variability (between sites, 5 to 30 m apart) in settlement of Chthamalus being the only spatial scale at which variability was detected in both locations.The composition of Chthamalus cohorts settling during one tidal cycle differed considerably between locations/species: settlers of C. stellatus were mainly cyprids; settlers of C. montagui during the day (when most settlement occurred) were essentially metamorphs.     

Spatial variation in the recruitment of the intertidal barnacles Chthamalus montagui Southward and Chthamalus stellatus (Poli) (Crustacea: Cirripedia) over an European scale

Spatial variation in the recruitment of the intertidal barnacles Chthamalus montagui and Chthamalus stellatus was examined over an European scale. The study was carried out using standardised protocols at a series of locations. The five locations chosen (SW Ireland, NW Spain, SW Portugal and NW and NE Italy) span a large part of the range of these species in Europe. The spatial scales were location (hundreds of kilometres) and shore (thousands of metres).Estimates of total cumulative recruitment (cyprids and metamorphs) summed over the year (April 1997 to March 1998) showed substantial variation between locations which was dependent on the species. Recruitment was highest in SW Portugal for C. montagui and in SW Ireland and NW Spain for C. stellatus. Overall recruitment of C. montagui was higher than that of C. stellatus at all locations except SW Ireland, where recruitment of the two species was not significantly different. There were significant differences among shores in each location.The recruitment period of both species varied with location, with recruitment beginning earlier further south. In general, recruitment of C. montagui and C. stellatus was recorded in 8 months in NW Spain and NE Italy, while only in 7 months in SW Ireland. Recruitment of C. montagui occurred in 10 months in SW Portugal, but no recruits of C. stellatus were found. In all locations there was at least one distinct peak of recruitment. In SW Ireland both species showed only one peak of recruitment, a month after initiation. At the more southerly Atlantic locations, as well as in the Mediterranean, two unequal peaks of recruitment were generally seen. During recruit census, the number of cyprids, in comparison to metamorphs, found at any location was very low. In SW Ireland and NW Spain cyprids of both species were found, while in SW Portugal and in the Mediterranean, only cyprids of C. montagui were found.     

The responses during development of the embryos of some common cirripedes to wide changes in salinity

The effect of hypo- and hypersaline media on the development of the embryos of the common cirripedes, Balanus balanoides, (L.), B. crenatus Brug., B. balanus (L.), B. perforatus Brug., Chthamalus stellatus (Poli), and Elminius modestus Darwin has been examined. These species represent littoral and sublittoral, boreo-arctic and warm-temperate, relatively steno- and euryhaline, and steno- and eurythermal forms. The range of salinity over which the embryos would develop to give free-swimming stage I nauplius larvae, no matter at what stage of development the cultures were started, was similar in all species, namely 15–20 to 40%. Low-salinity media cause cytolysis while high salinity media give grossly abnormal embryos which may, however, develop further. There seems little direct relation between salinity tolerance and that of the habitat in which the animals are found; a capacity for acclimation may be more important. The causes underlying the production of abnormalities are discussed.     

Patterns of adult abundance in Chthamalus stellatus (Poli) and C. montagui Southward (Crustacea: Cirripedia) emerge during late recruitment

The aim of this study was to investigate when adult distribution patterns are established in the barnacles Chthamalus stellatus and C. montagui. Adult ‘zones’ were identified by analysing field counts of both species at mid and upper shore heights. Monthly collections of cyprids, < 1 month old metamorphs and recruits (all metamorphosed individuals older than approximately 1 month) were made for C. stellatus and C. montagui in natural barnacle beds at six shores in SW Ireland. This was carried out over one year in 1996/1997, using a hierarchical sampling design. Abundance of total recruits (0-3 months old) was compared between adult zones after the main settlement season had ended. In addition, scales of variability in 0-3 month recruitment into adult zones were compared between the species at two scales: shores (1000s of metres) and sites within shores (10s of metres). Older recruits of each species, up to 11 months of age, were also compared between adult zones.The majority of settlement (measured as attached cyprids) occurred between August and October 1996. In October, there was no effect of adult zone on the abundance of total (0-3 month) recruitment up to that point in either species. Despite this homogeneity in recruitment between adult zones, significant spatial variation was found in 0-3 month recruits of both species at both of the scales examined. In C. stellatus the amount of variation associated with the larger scale (shore) was more than twice that of sites or of the residual variation (replicates within sites). 0-3 month recruitment in C. montagui was also most variable at the scale of shores but the residual variability (between replicates within site) was of similar magnitude to that of shores. Variability in 0-3 month C. montagui recruitment was relatively low at the scale of sites.There was a small but consistent input of recruits to adult zones over 9 months of the year, complicating the assessment of when adult patterns were set-up in these species. By June 1997, characteristic patterns of adult dominance had been established at all shores. Settlement had completely ceased by this time and individual barnacles were potentially 11 months old. Neither settlement nor early recruitment are significant in determining adult zonation patterns in these species. Instead, differential mortality patterns in individuals up to the age of 11 months are implicated in determining patterns of distribution of both species.     

Distribution and abundance of co-occurring chthamalid barnacles Chthamalus montagui and Chthamalus stellatus (Crustacea,Cirripedia) on the southwest coast of Portugal

Two co-occurring chthamalid barnacle species occur on the rocky shores of continental Portugal: Chthamalus stellatus (Poli) and Chthamalus montaguiSouthward. In the present study, patterns of distribution and abundance (density and percentage cover), both vertically (tidal level) and horizontally (wave action), were studied for each species on headlands (more wave action) and not on headlands (less wave action) and at two spatial scales (shore and site) and three tidal levels (low, mid and upper). Chthamalus montagui was significantly more abundant than C. stellatus in both degrees of wave action and at all tidal levels. Despite this great difference in abundance and considering each species individually, C. montagui was more abundant at mid tide-level, while C. stellatus was more abundant at the low tide-level, and C. montagui was less abundant on headlands, while C. stellatus was more abundant on headlands. Small-scale variability (between sites, tens of meters) of abundance of each species was detected, while differences on a larger scale (between shores, tens of kilometres) were not significant.     

Contrasting spatial heterogeneity of sessile organisms within mussel (Perna perna L.) beds in relation to topographic variability

We examined the spatial heterogeneity in three sessile rocky shore organisms, the mussel Perna perna, the barnacle Octomeris angulosa (Sowerby) and the red alga Gelidium pristoides (Turn.) at a range of continuous local scales along horizontal transects within mid- and upper mussel beds of South African shores. We also examined the relationships between variability of organisms and topographic features (rock depressions, slope, aspect), and between mussel, barnacle and algal variability over the same scales. To estimate spatial heterogeneity, we analyzed scaling properties of semivariograms using a fractal approach. Relationships between different variables at the different scales were examined by cross-semivariograms. Spatial dependence of P. perna variability increased with spatial dependence of topographic variability, so that scaling regions of mussel and topographic distributions corresponded well. This relationship often improved with larger local scales (mussel cover increased with depressions, steeper slope and aspect towards waves), while at smaller spatial scales, variability in mussel cover was less well explained by variability in topography. The variability of the barnacle O. angulosa exhibited spatial dependence, even on topographically unstructured shores. In contrast, the distribution of the alga G. pristoides revealed high fractal dimensions, showing spatial independence on topographically unstructured shores. Algae also showed a very strong negative relationship with mussels at most local scales, and a negative relationship with barnacles in upper zones, especially at larger local scales. Barnacles may show clear spatial dependence because of hydrodynamics (at larger local scales) and the need to find a future mate in close proximity (at smaller local scales), while algae may show a strong negative relationship with mussels because of competition for space.     

Fruit-coat and seed fats of Rhopalostylis, Elaeocarpus and Nestegis species

The fruit-coat fats of Rhopalostylis sapida, R. baueri (Palmae), Elaeocarpus dentatus (Elaeocarpaceae) and Nestegis cunninghamii (Oleaceae) and the seed fats of E. dentatus and N. cunninghamii contain as their major fatty acids palmitic 11–35%, oleic 13–68%, and linoleic 16–31%. The seed fat of E. dentatus contains 10% hexadecenoic acid and the fruit-coat fat of N. cunninghamii 13% linolenic acid.     

Effect of rock type on the recruitment and early mortality of the barnacle Chthamalus montagui

Discontinuities in distribution of sessile species due to changes in available habitat have rarely been investigated. In the English Channel, soft sedimentary rocks including chalk could potentially present a barrier to eastward range extension of the southern barnacle Chthamalus montagui. To test the effect of rock type on recruitment and mortality, prepared settlement tiles of four calcareous rocks that form important platforms close to existing limits of distribution were fixed to the shore at a site in south-west England, known to have consistently high larval settlement. Prior to fixation, the roughness parameter “R_a” and Potential Settlement Sites (PSS) index was measured. Recruitment was monitored photographically on four occasions during the settlement season and subsequent mortality for 7 months after the settlement season. By the end of the settlement season, recruitment on the hard Kimmeridge Cementstone was significantly less than on the other three rock types and attributed to low surface roughness and fewest Potential Settlement Sites (PSS), yet only 28% of variance could be attributed to PSS. Post-recruitment mortality was more variable, however after 7 months there were significant differences between rock types. Simultaneous surveys of post-recruitment mortality in natural populations showed that although recruitment on chalk can potentially be high, survivorship was relatively low. Thus rock type could be influential in setting species geographical limits.     

Studies in the biochemistry of cirripede eggs. IV. The free Amino-acid pool in the eggs of Balanus balanoides (L.) and B. balanus (L.) during development

Changes in the ‘free’ amino acids, betaine, and trimethylamine oxide during the development of the eggs of Balanus balanoides (L.) and B. balanus (L.) have been determined; the results are given in terms of μM/g dry wt, μM/g water, and μM/10⁶ eggs. The amino acids are derived from the yolk proteins the net composition of which is known. Free amino acids are present in considerable quantity, as is commonly the case with crustacean tissue. Changes in the individual amino acids are discussed. B. balanus eggs contain large, and relatively constant, amounts of sarcosine; its function is unknown but large quantities are present in the more highly evolved cirripedes so far examined. A possible relation between betaine glycine, and sarcosine relative to choline metabolism is considered. Large amounts of taurine are present. There is a striking increase in β-alanine in the late stages of development; in B. balanoides it comes to be the most, and in B. balanus the third most common amino acid; its possible involvement in purine metabolism is considered. The relation between the amounts of the various entities in the eggs and in the bodies of the adult are examined.     

Chthamalus stellatus (Poli) und C. depressus (Poli) in der adria

A study has been made of the ecology of Chthamalus stellatus (Poli) and C. depressus (Poli) in the region of Rovinj (Yugoslavia). The distribution has been examined at several localities of different habitat conditions particularly with respect to wave action.     

The vertical distribution of Chthamalus montagui and Chthamalus stellatus (Crustacea,Cirripedia) in two areas of the NW Mediterranean Sea

The Mediterranean Sea is characterised by a small tidal range (0.3–1 m). Despite this, intertidal communities are well established and their upper limits often extend above mean high water level. Organisms living in the intertidal region and in the supralittoral zone rely on both tides and wave action to perform their biological functions. Lack of food, desiccation and predation are common stresses in such a harsh environment. The present study deals with the vertical distribution of two species of intertidal barnacles, Chthamalus montagui Southward and Chthamalus stellatus (Poli), which are the main constituents of the barnacle belt along Mediterranean rocky shores. Previous work, carried out in the Atlantic, showed that where the distribution ranges of the two Chthamalus species overlap, C. montagui is more common in the upper barnacle zone while C. stellatus is dominant lower down. The main aims of our study are: (1) to establish if there is a relationship between position and extension of the barnacle belt on the shore and tidal range and/or wave exposure, (2) to test the hypothesis that in the study areas C. montagui is more abundant than C. stellatus high on the shore, and that the pattern is reversed lower down. Barnacle populations were monitored in summer 1998 in the Gulf of Genoa (Ligurian Sea) and in the Gulf of Trieste (North-Adriatic Sea). The two areas differ in tidal range and hydrodynamism, the former presenting quite strong wave action and a tidal range of 30 cm, the latter having limited wave action and 1 m tidal range. Three shores were randomly selected in each gulf and two transects on each shore. Counts of barnacles in 10 ^* 10 cm quadrats were done at different shore heights along each transect. The data was subjected to analysis of variance. Results showed that a more pronounced hydrodynamic regime corresponded to a shift of the barnacle belt towards the higher shore (Gulf of Genoa), while in more sheltered areas (Gulf of Trieste), the barnacle distribution was confined to the intertidal region. The relative spatial distribution of C. montagui and C. stellatus within the barnacle belt varied locally, even between transects on the same shore, and this obscured the distribution pattern along the vertical gradient. Nevertheless, it was still possible to conclude that at mid and high shore in Genoa, C. stellatus was more abundant than C. montagui, while in Trieste the pattern was reversed.     

基于28S, COI和Cytb基因序列的薜荔和爱玉子传粉小蜂分子遗传关系研究

薜荔和爱玉子均属于桑科榕属植物,二者为同一物种的原变种与变种的关系,早期研究认为这两种榕树与同一种传粉榕小蜂(Wiebesia pumilae (Hill))建立了稳定的互利共生关系,但近期在形态学、生态学、传粉生物学等方面对二者的研究结果表明,薜荔传粉小蜂和爱玉子传粉小蜂之间可能发生了遗传分化。实验用核糖体28SrDNAD1-D3区、线粒体Cytb及COI基因部分序列,对采自福建3个不同样地的薜荔传粉小蜂和3个不同品系的栽培爱玉子的传粉小蜂进行分析,结果表明:(1)薜荔传粉小蜂和爱玉子传粉小蜂的核糖体28S序列的碱基组成中A,T,G,C 4种含量较平均,C+G的平均含量(56%)稍高于A+T的含量(44%)。线粒体Cytb序列中A+T的含量(76.1%)明显高于C+G的含量(23.9%),COI序列中A+T的含量(71.9%)也明显高于G+C的含量(28.1%),这是膜翅目昆虫线粒体基因的普遍特征。在薜荔和爱玉子传粉小蜂的线粒体Cytb及COI基因中,密码子第三位点A+T的含量最高。(2)比较薜荔和爱玉子传粉小蜂的3种分子标记的变异范围显示,28S进化速度较Cytb及COI序列慢,比较保守,更适合科、亚科等较高分类单元的研究。薜荔传粉小蜂与爱玉子传粉小蜂之间的亲缘关系较近,采用Cytb与COI序列进行分析更为精确。(3)用Cytb及COI序列对薜荔传粉小蜂与爱玉子传粉小蜂之间的遗传距离进行分析显示,薜荔传粉榕小蜂个体间Cytb序列平均遗传距离为0.0054,爱玉子传粉小蜂个体间的Cytb遗传距离为0.0164;薜荔传粉小蜂与爱玉子传粉小蜂群体之间的Cytb序列平均遗传距离为0.1385;COI序列的薜荔传粉榕小蜂个体间遗传距离为0.0048,爱玉子传粉小蜂各样本间平均遗传距离为0.0102;薜荔传粉小蜂与爱玉子传粉小蜂群体间COI序列平均遗传距离为0.1896,两群体间的遗传距离(差异大于10%以上)明显大于群体内各样本之间的遗传距离,表明薜荔传粉小蜂与爱玉子传粉小蜂之间已经发生了很大的遗传分化,其变异水平达到了种间分化水平,即薜荔传粉小蜂与爱玉子传粉小蜂为两个不同的种。     

Age-stage,two-sex life table and food utilization efficiencies of Galerucella placida Baly (Coleoptera: Chrysomelidae) on two Polygonaceae weeds

Rumex dentatus L. and Polygonum glabrum Willd. (Polygonaceae) are important weeds of wheat and rice fields, respectively, in India and Pakistan. Adults and larvae of Galerucella placida Baly (Coleoptera: Chrysomelidae) feed both weeds. Therefore, we studied the biology of G. placida on two weed leaves using age-stage, two-sex life table at 21 °C, 65 ± 5% r.h. and 12L: 12D. We also studied food utilization indices of G. placida on these leaves. Further, we investigated the quantities of nutrients (total carbohydrates, proteins, lipids, amino acids and nitrogen) and antinutrients (total phenols, flavonols and tannins) of the leaves. Correlation analysis suggested that fecundity and the intrinsic rate of increase (r_m) of G. placida were positively correlated with nutrients of leaves, while negatively correlated with antinutrients. Faster larval development, higher longevity of adults and greater fecundity of G. placida were recorded on R. dentatus than P. glabrum. The r_m was higher on R. dentatus than P. glabrum. The nutrients were greater in R. dentatus than P. glabrum, while antinutrients were lower in R. dentatus than P. glabrum. The growth rate and consumption index were greater on R. dentatus than P. glabrum. The above results suggested that better nutritional quality of R. dentatus than P. glabrum influenced faster larval development, higher longevity of adults and greater fecundity of G. placida on R. dentatus. This study concluded that R. dentatus could be used for mass rearing of G. placida in biocontol program prior to release in fields for control of both these weeds.     

Isolation of highly polymorphic microsatellite markers from the intertidal barnacle Chthamalus montagui Southward

This study reports the isolation and characterization of seven highly polymorphic microsatellite loci in Chthamalus montagui (Crustacea, Cirripedia). The loci were isolated from a library constructed from genomic DNA enriched for CA repeats. The markers yielded three to 43 alleles per locus (mean 16.7) in samples averaging 49 individuals. Observed heterozygosity ranged from 0.08 to 0.58 (mean 0.39). These microsatellite loci will be valuable tools for population genetic studies of this species.     

Comparative SEM Studies of Lattice Organs: Putative Sensory Structures on the Carapace of Larvae from Ascothoracida and Cirripedia (Crustacea Maxillopoda Thecostraca)

Putative sensory structures, called lattice organs, were studied with scanning electron microscopy from ascothoracid or cypris larvae representing a wide range of families of the Ascothoracida and Cirripedia. These organs, situated dorsally on the carapace were, with few exceptions, always found in two anterior and three posterior pairs. The lattice organ morphology displayed by the Ascothoracida, a seta–like structure with a terminal pore, is believed to be the most plesiomorphic condition. Within the Cirripedia lattice organ morphology varied from types resembling the Ascothoracida in the Acrothoracica and the lepadomorph Capitulum mitella, to an elongate pore field with a larger terminal pore in most Thoracica and Rhizocephala. Akentrogonid Rhizocephala seem to display the most apomorphic condition. While lattice organ morphology was generally constant at the family level, cases were seen where closely related species such as Chthamalus stellatusand Chthamalus montaguishowed minor, but clear cut differences. Lattice organs in 2 + 3 pairs are argued to represent a synapomorphy for the Ascothoracida and the Cirripedia. The results confirm that the cyprid morphology at the ultrastructural level will prove to be of high value in estimating phylogeny within the Cirripedia.     

夏蜡梅及其主要伴生种叶的灰分含量和热值

分别于2006年7月、10月和2007年4月,对全光照、林缘和林下3种光环境下夏蜡梅及群落中35种主要植物叶的灰分含量和去灰分热值进行测定,分析它们在光合作用中对太阳能的固定和积累能力。不同光环境下夏蜡梅叶灰分含量的大小顺序都是全光照＞林缘＞林下,10月3种光环境下夏蜡梅叶灰分含量均高于4月和7月,均差异显著。4月、7月和10月,林下和全光照环境下的叶去灰分热值呈先下降后上升的趋势,而林缘中叶去灰分热值却逐渐下降。群落各层植物的灰分含量大小顺序为草本层＞灌木层＞间层＞乔木层,夏蜡梅灰分含量略低于灌木层灰分含量的平均值;各层次植物平均去灰分热值大小顺序为乔木层＞灌木层＞草本层＞间层,夏蜡梅平均去灰分热值低于间层。多数植物不同季节叶的灰分含量、去灰分热值均以10月最高。     

Variability for protein and oil quality in Lupinus albus

Amino acid composition and fatty acid composition were determined on seed samples of a range of white lupin (Lupinus albus) cultivars and accessions grown in either of two environments.Variability between genotypes was found for lysine, arginine and glutamic acid content, but not for the concentrations of other amino acids. The deficiency in sulphurcontaining amino acids, typical of legume proteins, was evident, with methionine and cyst(e)ine totalling only 2.2% of the protein. Variability was limited, indicating that improvement by breeding would be impracticable. Lupinus albus differed slightly from other lupin species in amino acid composition, having higher levels of threonine, tyrosine and isoleucine, but a lower level of glutamic acid than both L. angustifolius and L. luteus. Four low-alkaloid lines of L albus each had higher lysine content than the high-alkaloid line, but ‘Kiev Mutant’, despite earlier claims, had a lysine level no higher than the other three low-alkaloid lines.Fatty acid composition of the seed oil varied considerably between genotypes. Oleic acid ranged from 43.6 to 54.4% and linolenic acid from 6.7 to 15.2%, these two fatty acids being negatively correlated at one site. Linoleic acid content varied between 17.2 and 26.9% and was not correlated with other fatty acids. Total oil content averaged 9.6% with little variability between lines.It is concluded that, relative to other lupin species, L. albus has a more favourable amino acid profile for its utilisation in cereal-based diets for animals, particularly if the energy source is wheat, which is deficient in threonine. The higher oil content would be an important energy benefit to such diets and may allow their protein/energy balance to be maintained at higher levels of incorporation of L. albus seed meal than is possible with other lupin species.     

Early life-history processes and their implications for the invasion of the barnacle Balanus glandula

As invasions become increasingly prevalent, it is important to understand how spread may be moderated by environmental conditions. This study considered the effect of location and changing substratum temperature on the early life-history processes of the alien barnacle Balanus glandula and its native comparator, Chthamalus dentatus, along the South African coast. Using settlement plates of different colours, temperature was manipulated to assess settlement, mortality, recruitment and growth of the two species. These variables were tracked over 10 weeks using repeat photography. Unexpectedly, there was no evidence of an effect of temperature on early life-history processes of either species. Settlement by the two barnacles was spatially segregated, with B. glandula occurring only on the West Coast where it is the dominant intertidal barnacle, while C. dentatus settled only on the South Coast, which has only recently been invaded by the alien. Despite this, it was notable that the relative settlement of B. glandula on rock was higher than that of C. dentatus. However, the lack of mortality of the native resulted in comparable levels of recruitment among the species. Nonetheless, the propensity of B. glandula to settle sporadically, coupled with fast growth, suggests that the invader may still possess the ability to become dominant along the newly invaded South Coast. This study highlights that measurements of early life-history parameters may not adequately predict the future range and impacts of alien species unless interpreted within the broader context of the nature of the recipient region and species-specific traits of the invader.     

The effect of ecdysterone on cyprids of Balanus eburneus Gould

Synthetic ecdysterone in concentrations from 0.02 to 250 · 10^?6 causes developmental abnormalities in the cyprids of Balanus eburneus Gould. These cyprids are unable to attach themselves to the substratum, but readily metamorphose into barnacles with recognizable adult shell structures; these remain encased within the cyprid valves, but live only for a short time. The possible involvement of an ecdysone system in the metamorphosis of cirripedes is discussed.     

Field assessment of sub-epidermal leaf anthocyanin, PSII photochemistry,and the xanthophyll-cycle as photoprotective mechanisms in two morphs of Agave striata

We tested the hypothesis that leaf epidermal pigments screen light of particular wavelengths from reaching the photosynthetic machinery, reducing dependence on the xanthophyll-cycle as an energy dissipation process. Under field conditions, photosynthesis and water relations were studied in two morphs of Agave striata that differ in leaf coloration (green vs. reddish-purple). Titratable acidity, chlorophyll fluorescence, and internal and surface leaf temperatures were measured under low irradiance by shading (30%) and full sunlight (100%) for six days. We also measured the reflectance ratio (R_RED: R_GREEN), an index of anthocyanin content and the change in photochemical reflectance index (ΔPRI), an index of xanthophyll-cycle de-epoxidation state (xanthophyll conversion). Our results showed that both morphs expressed typical CAM-activity with no significant differences under sun vs. shade. However, shading did reduce titratable acids in both morphs. Both morphs were well hydrated, with the relative water content (RWC) being greater than 93%. Leaf surface temperature was found to be significantly higher during the day in the green morph compared to the red morph under sun and shade. Dark level fluorescence (Fo), photochemical efficiency of PSII (Fv/Fm), and the quantum yield of PSII electron transport (Φ_PSII) were higher in the red morph under sun compared to the green morph. The value of qN (non-photochemical quenching) was significantly higher during the day for the green morph compared to the red morph and this higher qN value was associated with a greater xanthophyll conversion and surface leaf temperature. However, sunlight did not predispose either of the morphs to photoinhibition. It is clear that the sub-epidermal anthocyanins serve as a photoprotective mechanism in the red morph, screening light energy from reaching the photosynthetic machinery and reducing dependence on the xanthophyll-cycle. We concluded that under natural light conditions the leaves of two morphs tested utilized differential photoprotective mechanisms.