Insect (Salebria sp.) infestation and impact on Vitellaria paradoxa C.F. Gaertn. fruit production in agroforestry parklands

Vitellaria paradoxa, known as Shea tree or karité, is one of the dominant trees of agroforestry parklands in Sahelian region with an immense commercial value. In this study, we examined infestation of fruit-bearing shoots and fruits on two sites in western Burkina Faso across different reproductive phenophases, crown heights and aspects. The number of infested and healthy shoots and fruits were counted on 60 reproductively active trees randomly selected from on-year shea trees in each site, using a metal frame (0.5 × 0.5 m) to mark a fixed area of the canopy for sampling. The shoot and fruit borer was identified as Salebria sp. (Lepidoptera:Pyralidae), which was not reported earlier. The proportion of infested trees and shoots varied significantly between sites and among reproductive phenophases (P < 0.0001). The site close to the natural forest had the highest infestation rate than distantly located site. Among reproductive phenophases, the proportions of infested trees and shoots were the highest during flowering and fruit set, respectively. Fruit infestation also varied significantly between sites, crown heights and aspects (P < 0.001). The site close to the natural forest and the crown with north-east aspect were heavily infested while the bottom part of the crown had the lowest infestation. As a whole, 49–80% of trees, 24–31% of shoots and 4–15% of fruits were found infested, depending on the site. These infestation levels combined with precocious flower and fruit abscissions would pose serious economic losses that justify a call for immediate pest control initiatives.     

Morphological variation in <Emphasis Type="Italic">Balanites aegyptiaca</Emphasis> fruits and seeds within and among parkland agroforests in eastern Niger

Balanites aegyptiaca (L.) Delile. is one of the priority indigenous fruit trees for rural communities in the West African Sahel. As part of a participatory tree domestication program in Niger, phenotypic variation in fruit and seed morphology was assessed in four natural populations in eastern Niger. Measured variables were weight of the fruit, seed coat and kernel; length and width of the fruit and seed (25 trees per population, 30 fruits per tree). Derived variables were the tree’s coefficient of variation (CVs) for each measured variable, and two sets of factor scores from principal components analysis of tree means and CVs. ANOVA indicated significant variation in all measured variables due to trees nested in populations. ANOVA and simple linear regression indicated significant geographic variation in some variables: the drier parts of the sample region tended to have heavier fruits and kernels, longer/narrower seeds, and lower within-tree variability in fruit and seed width. Length and width were strongly correlated between fruits and seeds, fruit weight was moderately correlated with seed dimensions, and CVs of fruit weight and width were moderately correlated with the CV of seed width. Some hypotheses for the geographic variation are presented, and some practical implications of the correlations for tree domestication programs are discussed.     

山西省中国沙棘天然种群优树表型变异研究

目的 为揭示山西省中国沙棘天然种群优树表型变异规律及其与生态因子的关系,为沙棘遗传资源收集、保存和品种创制提供技术支撑。 方法 以山西省中国沙棘天然种群分布区为研究对象,调查了11个中国沙棘天然种群110个优良单株的10个表型性状指标,采用方差分析和变异系数研究种群优树间的表型变异;应用相关分析揭示表型性状间及其与生态因子间的相关性;运用主成分分析和聚类分析进行了种群优树分类。 结果 中国沙棘10个表型性状在不同种群优树间呈显著（p < 0.05）或极显著（p < 0.01）差异,中国沙棘天然种群优树表型性状的平均变异系数为5.23%～37.42%。中国沙棘果实横径与果实纵径、百果质量、种子千粒质量、当年枝长均呈极显著（p < 0.01）正相关,与果形指数、结实密度呈极显著（p < 0.01）负相关;种子千粒质量与果实横径、果实纵径、百果质量呈极显著（p < 0.01）正相关;果形指数、果柄长、当年枝长与纬度因子呈极显著（p < 0.01）负相关;果实横径、果实纵径、百果质量、种子千粒质量、当年枝长与海拔因子呈极显著（p < 0.01）正相关。主成分分析结果表明：隰县种群优树的综合得分最高,五寨种群优树的综合得分最低。利用种群间欧式距离进行聚类分析,将11个中国沙棘天然种群优树分为4类,揭示了山西省中国沙棘优树表型性状未形成连续变异规律,具有随机变异的特点。 结论 山西省中国沙棘天然种群优树间存在丰富的表型变异。隰县种群优树的综合性状表现最好,可参考作为中国沙棘优良种质资源收集的重点区域。     

Growth and fruit production of the tree <Emphasis Type="Italic">Caryocar brasiliense</Emphasis> in the Cerrado of central Brazil

Caryocar brasiliense is a native tree found throughout the Cerrado savanna biome in central Brazil, and is exploited by rural population as food and industry. Although the abundance and popularity of this species in Cerrado have been an important component of local extractive economy, several aspects of sustainability as fruit production per tree size and growth rate have received little attention. We monitored, during two growing seasons, the stem growth rates and fruit production of tree in a wild population in Distrito Federal, central Brazil. The results showed a low growth rate of trees. The proportion of adult population fruiting was higher in 2006 than in 2007. For the smallest size (7.3-cm stem diameter) to begin fruiting, the estimated age was between 30 and 51 years old, and for tree with the largest stem diameter in the plot (43-cm diameter) the age was estimated to be between 110 and 153 years old. The whole fruit production by hectare was highly variable between years and was associated with differences in annual precipitation. The total fruit production was 1,004 fruits per ha (72.9 kg ha⁻¹) in 2006, and 299 fruits per ha (21.7 kg ha⁻¹) in 2007. The fruit production per tree was significantly positively correlated between 2006 and 2007 fruit season. Although an estimated fruit yield for whole Cerrado region is more than enough to support the actual demand, the slow growth rates and intensive harvesting indicates that more attention to sustainable management is required to avert demographic collapse of this cornerstone of the Cerrado extractive economy.     

Leafing, flowering and fruiting of Vitellaria paradoxa subsp. nilotica in savanna parklands in Uganda

Vitellaria paradoxa leafing, flowering and fruiting patterns were monitored in Otuke county (Lira district), northern Uganda, over a period of 25 months. The monitoring revealed that leaf shedding takes place in the middle of the dry season and the trees are in full leaf by the onset of the wet season. New leaves continue to appear on the new shoots while old leaves persist during the leaf-fall period. The pattern of leafing and leaf loss, flowering and fruiting are unimodal with major peaks in flowering and fruiting, although in the study area rainfall is bimodal. Flowering was concentrated in months when the atmospheric relative humidity begins to rise from an initially low value (around November), peaks three months later and usually ends when rainy conditions persist. Flowers produced during the rainy season usually abort. Fruiting starts at the end of the dry season (December/January) and peaks from February to April. Seed matures during the rainy season (March to May) and fruit harvesting occurs mainly from May to August, when the soil is well supplied with plant available water but coinciding with high pre-growing season famine risk in the community.This revised version was published online in November 2005 with corrections to the Cover Date.     

海拔高度对‘香玲’核桃生长结果习性的影响

以引种的‘香玲’核桃为试材,对襄阳市保康县不同海拔区域的核桃生长结果习性进行调查研究,结果表明:在相同的生长年限下,引种的‘香玲’核桃平均树高、平均地径在海拔700~800 m呈现最大值,单株冠幅面积和单株结果数量在600~700 m呈现最大值,700~800 m产量最不稳定,病果率在海拔600~700 m最低;在海拔800 m以上,随着海拔的升高,树体平均高度、树体平均地径、单株冠幅面积和单株结果数量均呈现下降的趋势。因此,保康县600~800 m区域是最适宜‘香玲’核桃引种的区域。     

山西野生沙棘结实性状和果实营养成分研究

了解沙棘种质资源特性是其种质创新和良种选育的基础。为给沙棘资源的开发利用和良种培育提供理论依据,分别从山西省沙棘野生资源重要分布区的右玉、交城、古交和沁源共采集了45个沙棘单株的果实样品进行观测与分析,比较分析了不同单株、不同采样地区、不同颜色果实的结实性状(结实密度、果实横径、果实纵径、果形指数、果柄长度和百果质量)和营养成分(可溶性固形物、可溶性糖、可滴定酸、VC和黄酮含量)及其差别,并对其性状特性与营养成分间的相关性进行了分析。观测结果表明:采集于交城的27号单株在结实特状和果实外观品质上的表现均最优,果实中的可溶性固形物、可滴定酸、VC、黄酮含量均最高的单株编号分别为10、7、32和27号;不同地区沙棘的结实密度、果柄长度和果实中VC、可溶性固形物含量间均存在显著性差异,其中采集于古交的沙棘果实其结实密度最大,采集于沁源的沙棘果实其VC含量最高,采集于古交的沙棘果实其可溶性固形物含量最高;不同颜色沙棘果实间其百果质量、结实密度、果实横径和纵径均存在显著性差异,黄色果的百果质量最大但结实密度最小。相关性分析结果表明:果实中的黄酮含量与VC含量间呈极显著正相关,而与可溶性糖含量间呈显著负相关。     

Rejuvenating indigenous trees in agroforestry parkland systems for better fruit production using crown pruning

The effects of crown pruning of mature indigenous fruit trees of Vitellaria paradoxa C. F Gaertn (commonly known as karité) and Parkia biglobosa (Jacq.) R. Br. ex G. Don (commonly known as néré) on recovery of crown size and fruit yield were assessed during 6 years in an agroforestry parkland system in Burkina Faso. Three treatments of crown pruning (total-pruning, half-pruning and a control of no-pruning) were applied to karité and néré. Each treatment comprised ten individuals of each species or a total of 60 trees of both species. Six years after pruning, higher recovery (81%) of crown diameter was achieved in total-pruned trees of néré as opposed to karité which recovered by only 73%. On the contrary, fruit production in total-pruned trees of karité recovered by 83% 5 years after pruning and fully (100%) 6 years after pruning as opposed to néré which recovered by only 57% 5 years after pruning but declined to 16% on the sixth year probably due to interannual variability. Fruit yields did not differ significantly between unpruned and half-pruned trees of both species throughout the experiment period. Total pruning may, therefore, be recommended to farmers to rejuvenate old trees of karité in parklands on the basis of fast recovery of fruit and slow recovery of crown in the species. Slow recovery of crown in pruned trees is the most desirable characteristic in parklands in order to avoid the negative effect of tree shade on adjacent crop.     

昆明引种地的元宝枫开花结实习性研究

以云南昆明地区引种栽培的元宝枫林为对象对其林木的开花结实习性进行了调查研究。结果表明,在昆明引种地元宝枫的花期主要集中在3月份;树冠东南西北4个方位的开花结实量基本无差异;上层树冠开花结实数是下层树冠开花结实数的3倍左右;结实数与开花数呈显著正相关,相关系数为0.642 8;从坐果到果实开始成熟期的落果率约为50%;果实各性状的株间变异特别大,变异系数8.20%~50.55%,但同一植株的果实形态和大小差异不大。     

Domestication of Dacryodes edulis: 1. Phenotypic variation of fruit traits from 100 trees in southeast Nigeria

A participatory approach to tree domestication is being pioneered by ICRAF and international partners in Cameroon and Nigeria. The domestication of Dacryodes edulis offers opportunities to improve the livelihoods of subsistence farmers and to diversify farming systems, such as cocoa farms. The trees produce marketable fruits as well as shade for cocoa and coffee. Twenty-four ripe fruits were collected from each of 100 D. edulis trees in Mgbuisi, southeast Nigeria by subsistence farmers. There was continuous and significant tree-to-tree variation in fruit mass (10.2±0.5–71.4±1.3 g), flesh mass (6.8±0.3– 62.2±1.2 g) and kernel mass (1.3±0.5–15.1±0.4 g). Mean fruit mass did not differ significantly between different land uses. Flesh mass:kernel mass ratio varied from 0.79 to 29.0. Two trees had fruits without kernels. There was also continuous and significant tree-to-tree variation in fruit length (39.0±0.6– 95.1±1.2 mm), fruit width (21.82±0.16–43.75±0.33 mm) and flesh thickness (1.82±0.1–6.39± 0.1 mm). Fruit length:width ratio varied from 1.35 to 3.18. Cooked fruits varied in taste with only 14% of trees getting the highest score. Similarly, fruits varied in oiliness with only 3% of trees getting the highest score. Thirteen skin colours were recorded, with the most common being dark blue (31%), greyish violet (29%) and deep blue (9%). Ninety-nine percent of the trees had been planted, with 57% in homegardens, 22% in crop fields, 17% in fallow land and 4% in cocoa. Tree height ranged from 4 to 22m, and DBH from 9.55 to 63.65 cm. Tree age ranged from 5 to 64 years. Farmers reported first fruiting from age 3 up to 22 years (average of 9.4 years). Most trees originated from seeds bought in markets (63%). Market prices of fruits from different trees, ranged from 2 to 12 fruits for 10 Naira (US0.07). These quantitative results will help in the identification of elite trees of D. edulis for cultivar development through clonal propagation.     

Baobab (Adansonia digitata L.) fruit production in communal and conservation land-use types in Southern Africa

Baobab fruit are harvested and used throughout Africa as an important source of food and are sold to generate income. Commercial use is increasing rapidly as derivatives of the fruit such as baobab seed oil and fruit pulp are being exported to Europe and North America. The cash derived from the sale of fruit support thousands of rural people. This study examines baobab fruit yields in an area being harvested for commercial use. It represents baobab populations and harvesting scenarios typically found in Southern Africa and is the first study in Africa to combine demographic and production data in determining baobab fruit yields.Fruit production was examined across five land-use types (nature reserves, rocky outcrops, plains, fields and villages) and over three consecutive years. Factors assessed included differences in life-stage, tree size, land-use type, inter-annual variation and quantifiable fruit predation.Results showed that adult trees produced 8 times more fruit than sub-adult trees. Fruit production fluctuated between size-classes and exhibited weak linear and logarithmic trends between fruit production and dbh and crown volume, respectively. There was high variation between trees with 41% of adult trees consistently producing <5 fruit per year, which we classed as ‘poor-producers’. Different land uses showed no significant differences in fruit production per tree, but where baboons were present, in nature reserves and rocky outcrops, predation of immature fruit resulted in up to 85% fruit loss. Villages and fields had the highest tree density and yielded the most fruit/ha. Inter-annual variation was significant with a two and a half fold difference between the highest and lowest year.The results of this study are important for economic planning and management and are key to determining sustainable harvesting levels of baobab fruit in Southern Africa.     

促进三台核桃中幼树生长结实技术措施研究

为了探寻能促进云南三台核桃中幼树生长结实的技术措施,从而为云南核桃的提质增效提供理论依据,以树龄为10~15 a的三台核桃中幼树为研究对象,采用修剪、螺旋环剥、花前灌水这3种技术处理进行了为期2年的试验研究,调查和综合比较分析了不同处理的新梢发枝力、果枝率、新梢生长量、单株产量。结果表明:螺旋环剥处理,能增加母枝抽发的新梢数量,但对新梢的营养生长却有一定的抑制作用,能使其果枝率和单株产量均有提高,其平均单株结果数可达508.3个,增产效果明显;修剪处理,增强了中幼树的发枝力,增加了母枝抽发的新梢数量,增产效果也较明显;花前灌水处理,促进了新梢的长度生长和粗度生长,促进了其营养生长,对其果枝率和单株结果数均一定的促进作用,但增产效果不很显著。     

Growth,flowering and fruiting of stecklings,grafts and seedlings of <Emphasis Type="Italic">Allanblackia floribunda</Emphasis> Oliver (Clusiaceae)

A study was carried out to assess the growth, flowering and fruiting of stecklings (rooted cuttings), grafts and seedlings of Allanblackia floribunda in Cameroun. Thirty-one individuals of each plantlet type were planted in May 2006. Height, collar and crown diameters were recorded in September and October, while flowering and fruiting were recorded each month from January to December. In 2014, the trees with the greatest height were those from seeds (6.98 ± 0.25 m), followed by those from grafts (1.65 ± 0.23 m) and cuttings (1.09 ± 0.21 m). Grafts started flowering and fruiting 3 years after planting, while seedlings started flowering and fruiting after four and 6 years, respectively. Stecklings still had not flowered 8 years after planting. Fruit weight and length from seed-origin trees are about seven times higher than grafts. Correlations between height and crown diameter were significant and positive irrespective of the nature of the planting material. In conclusion, grafts fruited earlier, while seedlings grew faster and had greater yields than grafts and stecklings of A. floribunda.     

陕西红花椒树冠结构对产量的影响

根据花椒树冠结构与产量的关系,确定影响花椒产量的主要结构因素,为丰产管理提供依据.对4个品种('大红袍'豆椒'黄盖狮子头'小红袍')的树龄、地径、树高、冠幅、标准枝(结果枝)数和产量进行调查,分析产量与树冠结构因子的关系.结果表明:(1)花椒适宜栽植密度约50株/666.7m2,栽植后树高应控制在2.50 m左右...     

环剥与环割处理对冬枣生长结果及果实品质的影响

以8年生冬枣为试材,研究不同时期环剥与环割对冬枣生长结果及果实品质的影响,旨在为改进枣树的栽培技术和提高枣树的产量与枣果质量提供理论依据。结果表明:主干环剥及主枝环割适宜在盛花期即开花30%~50%时进行,可明显提高冬枣果实及花序坐果率,提高产量;环剥与环割后果实的维生素C、总酸、总糖和可溶性固形物含量提高;环剥处理后的枣果总糖含量较环割处理高,硬度较环割处理低,果实品质更好;盛花后期即开花60%~80%进行环剥与环割,可提高枣果纵横径及单果质量,促使果实膨大,所以在栽培中可结合盛花期进行环剥、环割后,在盛花后期根据树势情况进行2次环剥、环割处理;木质化枣吊的坐果率、可溶性固形物含量、平均纵横径和单果质量均高于脱落性枣吊,说明在生产中应注意培养木质化枣吊,这是提升枣果产量及品质的有效方法。     

Domestication potential of Marula (Sclerocarya birrea subsp caffra)in South Africa and Namibia: 1. Phenotypic variation in fruit traits

Studies of tree-to-tree variation in fruit traits are a pre-requisite for cultivar development. Fruits were collected from each of 63 marula (Sclerocarya birrea) trees in Bushbuckridge, South Africa and from 55 trees from the North Central Region of Namibia. The South African trees were in farmers fields, communal land and natural woodland, at three sites: Acornhoek road, Allandale/Green Valley and Andover/Wits Rural Facility. The Namibian trees were all from farmers fields in three areas: North east, North west and West. The fruits were partitioned into skin and flesh/juice to examine the extent of the variation found in different components of marula fruits from different trees. Namibian fruits were significantly larger than those from South Africa (26.7 vs 20.1 g), due to their greater pulp mass (22.2 vs 16.2 g), especially the flesh/juice component. In South African fruits, those from farmers fields were significantly larger in all components (Fruit mass = 23.6 vs 19.3 and 18.0 g in natural woodland and communal land respectively). In Namibia, mean fruit mass did not differ significantly across sites (25.5 − 27.0 g). However, within each sample there was highly significant and continuous variation between trees in the pulp (S Africa = 7.5 − 31.3 g; Namibia = 8.3 − 36.0 g) and flesh/juice mass (S Africa = 2.2 − 7.6g; Namibia = 3.8 − 22. 6g), indicating the potential for selection of trees producing superior products. The fruits of the Namibian trees were compared with the fruits from one superior tree (‘Namibian Wonder) with a mean fruit mass of 69.9 g The percentage frequency distribution of fruit mass from trees in farmers fields in South Africa was skewed, while being bimodal in North east and North west populations from Namibia, suggesting that at these sites farmers are engaged in domestication through truncated selection of the best mother trees. It is concluded that there are trees in on-farm populations that have great potential to be propagated vegetatively as selected cultivars.     

Impact of bark and foliage harvesting on fruit production of the multipurpose tree <Emphasis Type="Italic">Afzelia africana</Emphasis> in Burkina Faso (West Africa)

In sub-Saharan Africa, extraction for daily livelihood needs often results in uncontrolled exploitation of bark and leaves of valuable medicinal and fodder trees. However, overharvesting of bark and foliage can reduce fruit production and threaten reproduction. This study evaluates the impact of combined bark and foliage harvesting on the performance of fruit production of Afzelia africana in Burkina Faso. We compared fruit and seed production at different harvesting intensities. Data on fruit yields were collected by stratified random sampling of 91 trees with no, low, severe, and very severe harvesting intensities. The fruit production varied with harvesting intensity, tree size and number of branches. Fruit and seed quantity and quality decreased with increasing harvesting intensity. However, no significant difference was detected between trees without and trees under low harvesting. Trees of all size classes under very severe harvesting intensity had no fruits. Under low harvesting impact, large trees had twice as many fruits as the control, whereas fruits were reduced by half to 95 % for the small trees. High harvesting intensity is an unsustainable practice that should be completely prohibited in order to ensure longterm persistence of Afzelia africana. Low harvesting intensity should be allowed, but only on large reproductive individuals.     

Land use impact on Vitellaria paradoxa C.F. Gaerten. stand structure and distribution patterns: a comparison of Biosphere Reserve of Pendjari in Atacora district in Benin

The shea tree, Vitellaria paradoxa, is a socio-economically important tree for the rural population in parts of West Africa. Our study assessed the current status of this native tree species with regard to increasing human pressure in northern Benin. We compared distribution of adult shea trees, seedlings and saplings in farmed lands with protected areas in the Biosphere Reserve of Pendjari (BRP). At our study site near BRP, agricultural activities foster recruitment of shea trees by regularly cropping of vegetation cover. Furthermore, traditional farming practices preserve adult individuals thus permitting regular fruit harvests. Consequently, most of the tallest and largest individuals of shea trees are found in framed lands. In contrast, the highest density of juvenile trees including seedlings (dbh <5 cm) and saplings (dbh 5–10 cm) occurred within BRP. Saplings were negatively affected by farming activities. Furthermore, spatial point pattern analysis revealed differences in the spatial structure of juveniles. Juveniles showed significant aggregations at small scale (<20 m) in BRP as well as significant and positive small-scale associations with adult trees. This contrasts with farmed lands where we did not find such spatial patterns at similar small scale but only a weak aggregation between juveniles and absence of association (attraction) of adults to juveniles. Although our analyses indicate that shea trees are rather well preserved, we conclude that the observed severe reduction of saplings in farmed lands is likely to negatively impact the long-term viability of the tree population. Therefore agroforestry practices must consider the preservation of sapling populations in farming areas for long-term conservation.     

腾冲红花油茶果实成熟度及堆沤处理对油产量及其品质的影响

选择38个腾冲红花油茶优株,设置八成熟采果、近生理成熟采果与及时脱粒、堆沤12d后脱粒组合而成的4种果实采收脱粒处理,对其主要产量、品质指标进行测定和分析.结果表明:4种处理间产量、品质达极显著差异(P＜0.01);果实八成熟采收导致产量严重损失,其仁油率、籽油率、果油率分别降低11.9％、18.2％和31.7％,籽油酸价亦降低10.5％而利于储存;近生理成熟采收“堆沤”处理与及时脱粒比较,其仁油率降低4.5％,而籽油酸价则提高7.3％;因此,腾冲红花油茶果实宜在生理成熟时采收并及时脱粒.研究结果为确定腾冲红花油茶果实合适采收期和采后处理方式提供了技术依据.     

Relationships between spur- and orchard-level fruit bearing in almond (Prunus dulcis)

Almond is often considered to be a moderately alternate-bearing species but historical yield data typically do not exhibit clear patterns of alternate bearing at the orchard level, while research has indicated that spurs (the main fruit bearing unit in almond trees) rarely produce fruit in two subsequent years. The objective of the present work was to analyze the bearing behavior of almond trees at both the orchard level and the individual spur level over multiple years to explain this apparent paradox. The 10-year yield patterns of three almond cultivars grown at three different sites within California were analyzed for tendencies of alternate bearing at the orchard level. At the individual spur level, data on spur viability, and number of flowers and fruits per spur were collected on 2400 individually tagged spurs that were observed over 6 years to characterize bearing at that level. At the orchard level one cultivar (Nonpareil) did exhibit a tendency for alternate bearing at one site (Kern) but other cultivars and sites did not. The orchard and the individual trees in which the spur population study was conducted showed tendencies for alternate bearing but the spur population did not. Only a relatively small percentage of the total tagged spur population bore fruit in any given year and therefore while individual fruiting spurs exhibited a high level of non-bearing after fruiting the previous year the spurs that did produce fruit in any year generally did not constitute enough of the total spur population to exhibit alternate bearing at the whole population level. Our results suggest that annual bearing fluctuations in almond are probably mainly due to year-to-year variations of parameters affecting fruit set and that high rates of fruit set in a given year may involve a larger-than-normal percentage of a spur population in fruit bearing. This would limit the size of the spur population available for flowering in the subsequent year and could cause alternate year bearing. However, from historical records, this would appear to be the exception rather than a normal circumstance. Therefore, almond should not be considered to be a strictly alternate-bearing species.