Pollinator preferences and the persistence of crop genes in wild radish populations (Raphanus raphanistrum, Brassicaceae)

Crop-weed hybridization can potentially influence the evolutionary ecology of wild populations. Many crops are known to hybridize with wild relatives, but few studies have looked at the long-term persistence of crop genes in the wild. This study investigated one factor in the hybridization process in radish: differential pollinator visitation to wild radish (Raphanus raphanistrum) vs. crop-wild F1 hybrids (R. sativus x R. raphanistrum). Wild genotypes had yellow flowers, a recessive single-locus trait, whereas hybrids always had white or pale pink flowers. In experimental arrays in northern Michigan, total pollinator visitation was significantly biased toward wild plants when the frequencies of wild and hybrid plants were equal. Syrphid flies, the most frequent visitors, preferred wild plants while bumble bees showed no preference. This pattern was also observed when hybrid plants were overrepresented in the array (12 hybrid:2 wild). In contrast, when hybrid plants were rare (2 hybrid:12 wild), neither morph was preferred by any pollinator group. Later in the summer, pollinators were also observed in a large experimental garden with nearly equal frequencies of wild and hybrid plants. Cabbage butterflies (Pieris rapae) strongly overvisited wild plants, while bumble bees showed a slight preference for hybrids. Taken together, these studies suggest that F1 hybrids may not be at a disadvantage with regard to pollinator visits when they occur at low frequencies or when bumble bees are frequent flower visitors. Thus, variation in the proportion of white-flowered morphs among wild radish populations could be influenced by different histories of crop-to-wild hybridization, as well as by variation in the composition of local pollinator taxa.     

Flower morphometry of Rhizophora mangle (Rhizophoraceae): geographical variation in Mexican populations

We explored the patterns of intra- and interpopulation variation in flower morphology of the red mangrove, Rhizophora mangle. Twelve populations in Mexico were studied: five from the Gulf of Mexico and the Caribbean Sea, and seven from the Pacific Coast. Six metric floral attributes were measured from a sample of 1370 flowers. Significant differences among populations were found for all six attributes. Because floral attributes were all correlated, scores derived from principal factor analysis were used to describe the variation in flower morphology. Two factors explained essentially all of the variance in flower morphology. Corolla and calyx size had a strong effect on factor 1, while gynoecium size had the higher effect on factor 2. Nested analyses of variance on the scores from both factors revealed significant differences among coasts, among populations within coasts, and among plants within populations. Nonetheless, this variation cannot be explained as a result of clinal variation, as indicated by a series of regression analyses. Cluster analysis (UPGMA) showed that a population from the Pacific coast was clustered together with those of the Atlantic, and the arrangement of populations within each coast showed no evident geographical pattern. We propose that frequent events of extinction and recolonization by a few individuals, followed by selfing, may produce differentiation among populations of red mangrove.     

Distinct feeding behavior between sexes of shape Frankliniella occidentalis results in higher scar production and lower tospovirus transmission by females

Feeding behavior and scar production of male and female F. occidentalis (Pergande) (Thysanoptera: Thripidae) were studied in relation to transmission of tomato spotted wilt tospovirus (TSWV). Electrical penetration graph (EPG) analysis showed that females feed more frequently and intensively than males. The feeding intensity, reflected by silvery scar production and studied by an image analysis system, demonstrated that females induced more numerous scars than males. At the same time, males transmitted TSWV with a higher efficiency than females, indicating that TSWV transmission and scar production are not positively correlated. Furthermore, males produced significantly more local lesions of TSWV than females. These quantitative differences in scar production and transmission of TSWV can be explained by the lower mobility and higher consumption rate of females. The influence of the sex-ratio on crop damage and virus transmission, and thus to the spread of TSWV, is emphasized.     

Do the habitats,mouth morphology and diets of the mullids Upeneichthys stotti and U. lineatus in coastal waters of south-western Australia differ?

Two benthic carnivorous goatfish (Mullidae), Upeneichthys stotti (max total length, L _T= 179 mm) and U. lineatus (max L _T= 257 mm), were trawled from the inner continental shelf waters of Western Australia. U. stotti was found almost exclusively offshore at 20–35 m depth, while U. lineatus was most abundant inshore at 5–15 m depth. Smaller individuals of both species ate small, thin-shelled mysids, tanaids and amphipods, while larger fish ate large, hard-bodied isopods, carid decapods and brachyuran crabs. Classification and ordination of the mean volumetric percentage contributions of the prey (dietary samples) of both species from all sites and in each season did not lead to a clear separation between these two species. However, ordination demonstrated that the dietary samples of the two species were distinct when the two species were found together, and when fish of sequential 20-mm length intervals were used. The interspecific size-class differences were consistent with the results obtained using Schoener's overlap index, for which values >0·6 were recorded for only two of the 45 possible interspecific pairwise comparisons. Since these interspecific differences occurred despite virtually identical mouth sizes and morphologies, the two species must feed in a slightly different manner and/or in different microhabitats. While most comparable-sized fish ate tanaids and amphipods, U. stotti ate more relatively mobile epibenthic mysids, cumaceans and carid decapods, whereas U. lineatus ate more larger and slower-moving burrowing bivalves, onuphid polychaetes and brachyuran crabs. The partial partitioning of habitats, when combined with differences in the diet, would help facilitate the co-existence of these two mullids when they are abundant.     

Stunting and flower buds deficiency of Lilium sp.: a new phytoplasma associated disease

The presence of phytoplasmas in Lilium sp. showing severely stunted growth, leaf malformation and flower buds deficiency was demonstrated for the first time using polymerase chain reaction assays with primers amplifying phytoplasma 16S rDNA regions. These phytoplasmas were found in leaves as well as roots and bulb scales of symptomatic and CMV and/or LSV affected and asymptomatic virus-free lilies.     

永久型70kD热休克蛋白在白菜花发育过程中的免疫组织化学定位

利用免疫组织化学技术研究了永久型热休克蛋白ＨＳＣ７０在白菜花各组织中的分布。结果表明：在正常温度条件下,ＨＳＣ７０在小孢子母细胞、四分体细胞、花药壁绒毡层细胞中分布最多,在花原基、花托的维管组织、花粉母细胞以及发育早期的胚珠中的表达也较多。该结果与其他人用核酸杂交、同位素示踪等技术所得结果基本一致,本文对ＨＳＣ７０在白菜花不同组织中的分布与其功能的关系进行了初步讨论。     

CaMADS1, a MADS box gene expressed in the carpel of hazelnut

Hazelnut (Corylus avellana L.) is a species of economic interest that shows a peculiar floral biology. Unlike most of the angiosperms, which produce ovules during floral development such that they are ready for pollen at anthesis, hazelnut ovary development is delayed and triggered by compatible pollination. In order to elucidate the mechanisms regulating this unusual process and the role of the MADS box genes in ovary development, a cDNA library from pollinated styles of hazelnut was screened with a mixture of MADS box genes from different plant species. CaMADS1 (Corylus avellana MADS box), a floral-specific MADS box gene, was isolated, and characterized as belonging to the sub-family of the AGAMOUS genes. Northern blot, RT-PCR analyses and in situ hybridization experiments show a precise correlation between ovary development and CaMADS1 expression, indicating a role of this MADS box gene in the processes of floral organogenesis.     

The ontogeny of foragwehaviour in desert ants, Cataglyphis bicolor

Abstract. 1. Individually foraging desert ants, Cataglyphis bicolor , exhibit short foraging lives (half lifetime, i.e. half-time of the exponential decay function: 4.5 days), in which they perform 3.7 ± 1.9 foraging runs per day.
2. During their short lifetime foraging period the ants increase the duration of their foraging round trips (up to 40.0 ± 24.6 min per run), the maximal distance of individual foraging runs (up to 28.2 ± 4.1 m), and their foraging success, i.e. the ratio of successful runs to the total number of runs (up to 0.70).
3. The parameter that increases most dramatically during a forager's lifetime is direction fidelity, i.e. the tendency to remain faithful to a particular foraging direction.
4. A model based on some simple behavioural rules is used to describe the experimental findings that within an isotropic food environment individual ants develop spatial foraging idiosyncrasies, and do so at a rate that increases with the food densities they encounter.
5. Finally, it is argued that in functional terms direction fidelity is related to the navigational benefits resulting from exploiting familiar (route-based) landmark information, and hence reduces round-trip time and by this physiological stress and predatory risk.     

Life history and locomotion in Cebus capucinus and Alouatta palliata

As an individual matures from birth to adulthood, many factors may influence the positional repertoire. The biological and behavioral changes that accompany a growing individual are expected to influence foraging strategy, social status and interaction, diet, predator avoidance strategies, and ultimately positional behavior as a behavioral link between anatomy and the environment. In this work, positional behavior is considered as an important feature of life history in juvenile and adult white‐faced capuchins (Cebus capucinus) and mantled howling monkeys (Alouatta palliata) inhabiting the same tropical forest in Costa Rica. During growth and development ontogenetic changes in body size, limb proportions, and motor skills are likely to influence locomotion and posture through the arboreal canopy. I collected data on positional behavior, activity, branch size, branch angle, and crown location during a 12‐month period at Estación Biológica La Suerte in northeastern Costa Rica. Life history timing and differences in rates of growth did not predictably influence the development of adultlike positional behaviors in Cebus and Alouatta. Young Cebus resembled the adult pattern of positional behavior by 6 months of age while howlers exhibited significant differences in several positional behavior categories through 24 months of age. The positional repertoire of both species revealed similarities in the types of modes used during feed/forage and travel in juveniles and adults. Data presented here suggest that the environment exerts different pressures on growing Cebus and Alouatta that may relate to diet, energy expenditure, foraging skill, and/or social learning. Am J Phys Anthropol, 2009 © 2009 Wiley‐Liss, Inc.