Pollination by nectar-foraging pompilid wasps: a new specialized pollination strategy for the Australian flora.

The Pompilidae is a cosmopolitan and diverse group of wasps, which commonly feed on nectar. However, pollination systems specialized on pompilids have not been documented in detail outside of southern Africa. Here, we studied Caladenia drummondii (Orchidaceae) where, based on floral traits and preliminary field observations, we predicted pollination by sexual deception of male pompilid wasps. Detailed pollinator observations were undertaken using floral baiting experiments at sites spanning 375 km. Following evidence for nectar on some flowers of C. drummondii, the sugar content on the labellum was analysed by GC-MS. Floral spectral reflectance was measured and compared with Caladenia using other pollination strategies. Males of a single species of pompilid wasp (Calopompilus sp.) were the only visitors capable of pollinating C. drummondii. Attempts to feed from the surface of the labellum were frequent and were associated with removal and deposition of pollinia. GC-MS analysis revealed larger quantities of sugar on the labellum than reported in other Caladenia species. While no sexual or courtship behaviour was observed, the zig-zag and circling flight on approach to the flower is suggestive of odour-based attraction. Floral spectral reflectance was similar to sexually deceptive Caladenia. This study represents the first confirmation of a specialized pompilid pollination system outside of Africa. Although pollination occurs during nectar-foraging, long-distance sexual attraction cannot be ruled out as an explanation for the exclusive male visitation. The similarity in floral spectral reflectance to other Caladenia indicates colour may not impose a constraint on the evolution of pollination by pompilids.

A specialised pollination system using nectar-seeking thynnine wasps in Caladenia nobilis (Orchidaceae).

Caladenia is a diverse Australian genus that is exceptional among orchids in having both species pollinated by food-seeking and sexually deceived insects. Here, we investigated the pollination of Caladenia nobilis, a species predicted to be food-deceptive due to its large, cream-coloured and apparently nectarless flowers. Pollinator observations were made using experimental clumps of flowers. Measurements of floral colour were undertaken with a spectrometer, nectar was tested using GC-MS, and reproductive success was quantified for 2 years. While C. nobilis attracted nine species of insect, only males of the thynnine wasp Rhagigaster discrepans exhibited the correct size and behaviour to remove and deposit pollen. Male R. discrepans attempted to feed from the surface of the labellum, often crawling to multiple flowers, but showed no evidence of sexual attraction. Most flowers produced little or no nectar, although some may provide enough sucrose to act as a meagre reward to pollinators. Floral colouration was similar to a related Caladenia species pollinated by sexual deception, although the sexually deceptive species had a dull-red labellum. Reproductive success was generally low and highly variable between sites and years. In addition to most visitors being of inappropriate size for pollinia removal, the lack of response to the orchid by several co-occurring species of thynnine wasp suggests filtering of potential pollinators at the attraction phase. Our discovery of a pollination strategy that may be intermediate between food deception and food reward raises the question, how many putatively rewardless orchids actually produce meagre amounts of nectar?

Evolutionary relationships among pollinators and repeated pollinator sharing in sexually deceptive orchids.

The mechanism of pollinator attraction is predicted to strongly influence both plant diversification and the extent of pollinator sharing between species. Sexually deceptive orchids rely on mimicry of species-specific sex pheromones to attract their insect pollinators. Given that sex pheromones tend to be conserved among related species, we predicted that in sexually deceptive orchids, (i) pollinator sharing is rare, (ii) closely related orchids use closely related pollinators and (iii) there is strong bias in the wasp lineages exploited by orchids. We focused on species that are pollinated by sexual deception of thynnine wasps in the distantly related genera Caladenia and Drakaea, including new field observations for 45 species of Caladenia. Specialization was extreme with most orchids using a single pollinator species. Unexpectedly, seven cases of pollinator sharing were found, including two between Caladenia and Drakaea, which exhibit strikingly different floral morphology. Phylogenetic analysis of pollinators using four nuclear sequence loci demonstrated that although orchids within major clades primarily use closely related pollinator species, up to 17% of orchids within these clades are pollinated by a member of a phylogenetically distant wasp genus. Further, compared to the total diversity of thynnine wasps within the study region, orchids show a strong bias towards exploiting certain genera. Although these patterns may arise through conservatism in the chemical classes used in sex pheromones, apparent switches between wasp clades suggest unexpected flexibility in floral semiochemical production. Alternatively, wasp sex pheromones within lineages may exhibit greater chemical diversity than currently appreciated.

Paternity analysis reveals wide pollen dispersal and high multiple paternity in a small isolated population of the bird-pollinated Eucalyptus caesia (Myrtaceae).

Optimal foraging behaviour by nectavores is expected to result in a leptokurtic pollen dispersal distribution and predominantly near-neighbour mating. However, complex social interactions among nectarivorous birds may result in different mating patterns to those typically observed in insect-pollinated plants. Mating system, realised pollen dispersal and spatial genetic structure were examined in the bird-pollinated Eucalyptus caesia, a species characterised by small, geographically disjunct populations. Nine microsatellite markers were used to genotype an entire adult stand and 181 seeds from 28 capsules collected from 6 trees. Mating system analysis using MLTR revealed moderate to high outcrossing (tm=0.479-0.806) and low estimates of correlated paternity (rp=0.136±s.e. 0.048). Paternity analysis revealed high outcrossing rates (mean=0.72) and high multiple paternity, with 64 different sires identified for 181 seeds. There was a significant negative relationship between the frequency of outcross mating and distance between mating pairs. Realised mating events were more frequent than expected with random mating for plants <40 m apart. The overall distribution of pollen dispersal distances was platykurtic. Despite extensive pollen dispersal within the stand, three genetic clusters were detected by STRUCTURE analysis. These genetic clusters were strongly differentiated yet geographically interspersed, hypothesised to be a consequence of rare recruitment events coupled with extreme longevity. We suggest that extensive polyandry and pollen dispersal is a consequence of pollination by highly mobile honeyeaters and may buffer E. caesia against the loss of genetic diversity predicted for small and genetically isolated populations.

Mismatch in the distribution of floral ecotypes and pollinators: insights into the evolution of sexually deceptive orchids.

Plants are predicted to show floral adaptation to geographic variation in the most effective pollinator, potentially leading to reproductive isolation and genetic divergence. Many sexually deceptive orchids attract just a single pollinator species, limiting opportunities to experimentally investigate pollinator switching. Here, we investigate Drakaea concolor, which attracts two pollinator species. Using pollinator choice tests, we detected two morphologically similar ecotypes within D. concolor. The common ecotype only attracted Zaspilothynnus gilesi, whereas the rare ecotype also attracted an undescribed species of Pogonothynnus. The rare ecotype occurred at populations nested within the distribution of the common ecotype, with no evidence of ecotypes occurring sympatrically. Surveying for pollinators at over 100 sites revealed that ecotype identity was not correlated with wasp availability, with most orchid populations only attracting the rare Z. gilesi. Using microsatellite markers, genetic differentiation among populations was very low (GST = 0.011) regardless of ecotype, suggestive of frequent gene flow. Taken together, these results may indicate that the ability to attract Pogonothynnus has evolved recently, but this ecotype is yet to spread. The nested distribution of ecotypes, rather than the more typical formation of ecotypes in allopatry, illustrates that in sexually deceptive orchids, pollinator switching could occur throughout a species' range, resulting from multiple potentially suitable but unexploited pollinators occurring in sympatry. This unusual case of sympatric pollinators highlights D. concolor as a promising study system for further understanding the process of pollinator switching from ecological, chemical and genetic perspectives.

Genetic structure of Melanotaenia australis at local and regional scales in the east Kimberley, Western Australia.

The Kimberley region of Western Australia possesses a poorly studied freshwater fish fauna with high endemism in an aquatic landscape subject to monsoonal floods and dry season isolation. In the first population genetic study of freshwater fish in this region, the authors tested the effects of geographic barriers on genetic structure at multiple spatial scales in east Kimberley populations of the western rainbowfish, Melanotaenia australis, the most widespread and abundant species in the region. Based on allozyme comparisons, hierarchical analysis of F(ST) revealed increasing genetic subdivision with spatial scale. Minimal genetic structure within creeklines demonstrated that wet season dispersal, rather than dry season isolation, determines genetic structure at small scales. At the scale of sub-catchments, a pattern of isolation by distance along creeklines was evident. Genetic subdivision between adjacent river systems was greater between rivers separated by a plateau than by lowlands. This implies greater connectivity of populations in lowland areas and may explain the greater similarity of the east Kimberly freshwater fish fauna with lowlands to the east than with the more rugged regions to the west. Similarly, greater connectivity between lowland populations may account for the on-average larger distribution of lowland Melanotaeniids.

Consumer-based optimization of a third-generation product made from peanut and rice flour.

Indirectly puffed snacks were produced by an extrusion process with partially defatted (12% fat) peanut flour (30%, 40%, 50%) at different levels of screw speed (200, 300, 400 rpm) and feed rate (4, 5, 6 kg/h). Extrudates were dried to obtain half-products (11% to 12% MC) followed by puffing with deep-fat frying. The puffed snack prototypes were subjected to consumer acceptance test. Consumers rated higher than 6.0 (= like slightly) for all products produced within the experimental factor ranges on the attributes of crispness and texture, whereas consumer scores for appearance, color, flavor, and overall liking were lower than 6.0 for the product containing 50% peanut flour regardless of screw speed and feed rate. The product extruded with 50% peanut flour at screw speed of 400 rpm and feed rate of 6 kg/h received the lowest score of 5.5 on overall liking in a 9-point hedonic score. Predicted regression models indicated that feed rate had the largest effect on consumer attributes followed by peanut flour and screw speed. From the superimposed contour plot of individual contour plot of consumer attributes, the optimum region was identified as the area beginning at the 42.0% to 43.0% peanut flour and 4.0 kg/h feed rates, rising to a maximum at 45% peanut flour and 4.6 kg/h feed rates and decreasing to the 33.0% to 34.0% peanut flour and 6.0 kg/h feed rates. Verification confirmed the ability of predictive regression models to identify peanut-based snacks, which would be scored higher than 6.0 by consumer evaluation.

Effect of milling and preparation method on the physical properties and quality of moin-moin (steamed paste).

Moin-moin is steamed cowpea paste native to Nigeria. This product is classified as a protein/starch gel with the dominate portion of the gel network consisting of cowpea starch. Moin-moin was prepared from starting materials (cowpea meal and cowpea flour) and compared to moin-moin prepared from dry, whole, undecorticated cowpea seeds. Texture profile measurements showed that moin-moin made from cowpea flour (small particle size) formed a firmer structure when compared to moin-moin made from either cowpea meal or whole, dry cowpea seeds. Starting materials with smaller particle sizes and longer cooking times produced stickier moin-moin. The cowpea solids to water ratio was shown to affect the firmness of moin-moin, where a 3.75:1 ratio of solids to water produced a firmer product than other concentrations. Generally, color was unaffected across treatment regimens as identified by an expert sensory panel, although instrumental color measurements showed significant differences for hue angle and chroma. This study demonstrated that the particle size of this food ingredient contributes significantly to its functionality in food formulations.

Effects of twin-screw extrusion of peanut flour on in vitro digestion of potentially allergenic peanut proteins.

Partially defatted peanut flour was processed in a twin-screw extruder. Resulting extrudates were dried, ground, and incubated with simulated gastric fluid for various time periods. Soluble protein content of the resulting digesta was measured after 10% trichloroacetic acid treatment to evaluate the digestibility. In vitro digestion using pepsin increased the solubility of peanut protein in 10% trichloroacetic acid solution from 2 to 6% to 65 to 75%. Four strong IgE-binding subunits (65, 22, 17, and 14 kDa) were found with immunoblotting in peanut proteins extracted from unextruded peanut flour; no IgE-binding bands were observed in extrudates. The 65-kDa (putative Ara h 1) subunit was insolubilized during extrusion, and its IgE-binding property was susceptible to in vitro digestion. Following extrusion cooking, no IgE-binding bands were detected by immunoblotting, including the strongly IgE-binding 14-kDa fraction, a strong IgE-binding band from native peanut protein that is stable in pepsin. The 22- and 17-kDa (putative Ara h 2) subunits retained a small amount of IgE-binding potential and became susceptible to pepsin hydrolysis after extrusion.

Ethanol-mediated variations in cellular fatty acid composition and protein profiles of two genotypically different strains of Escherichia coli O157:H7.

Two strains of Escherichia coli O157:H7 were grown in tryptic soy broth (TSB, pH 7.1) supplemented with 0, 2.5, 5.0, 7.5, and 10% ethanol at 30 degrees C for up to 54 h. Growth rates in TSB supplemented with 0, 2.5, and 5.0% ethanol decreased with an increase in ethanol concentration. Growth was not observed in TSB supplemented with 7.5 or 10% ethanol. The pH of TSB containing 5.0% ethanol decreased to 5.8 within 12 h and then increased to 7.0 at 54 h. The ethanol content in TSB supplemented with 2.5 or 5.0% ethanol did not change substantially during the first 36 h of incubation but decreased slightly thereafter, indicating utilization or degradation of ethanol by both strains. Glucose was depleted in TSB supplemented with 0, 2.5, or 5.0% ethanol within 12 h. Cells grown under ethanol stress contained a higher amount of fatty acids. With the exceptions of cis-oleic acid and nonadecanoic acid, larger amounts of fatty acid were present in stationary-phase cells of the two strains grown in TSB supplemented with 5.0% ethanol for 30 h than in cells grown in TSB without ethanol for 22 h. The trans-oleic acid content was 10-fold higher in the cells grown in TSB with 5.0% ethanol than those grown in TSB without ethanol. In contrast, cis-oleic acid was not detected in ethanol-stressed cells but was present at concentrations of 0.32 and 0.36 mg/g of cells of the two strains grown in TSB without ethanol. Protein content was higher in ethanol-stressed cells than in nonstressed cells. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein profiles varied qualitatively as affected by the strain and the presence of ethanol in TSB. An ethanol-mediated protein (28 kDa) was observed in the ethanol-stressed cells but not in control cells. It is concluded that the two test strains of E. coli O157:H7 underwent phenotypic modifications in cellular fatty acid composition and protein profiles in response to ethanol stress. The potential for cross protection against subsequent stresses applied in food preservation technologies as a result of these changes is under investigation.

The performance of broiler chicks fed diets containing extruded cottonseed meal supplemented with lysine.

Three experiments were conducted to test the hypothesis that extruding cottonseed meal (CSM) with supplemental lysine improves its feeding value by detoxifying gossypol. The performance of 1-wk-old straight-run Peterson x Arbor Acres broiler chicks fed diets containing 20% feed-grade or extruded CSM was compared with that of control chicks fed corn and soybean meal-based broiler rations. All diets were formulated to meet minimum NRC requirements. Lysine levels were adjusted by addition of synthetic lysine at rates of 0.5 to 2.0% of the protein in CSM. In all experiments, weight gain, feed intake, and feed conversion ratio (FCR) of broilers at 21 d were significantly affected by the diets. Feeding feed-grade and extruded CSM resulted in decreased body weight gain, increased feed intake, and inefficient feed utilization. When 2% lysine was added to feed-grade or extruded CSM, the body weight gains of chicks were not significantly different from those fed the control diet. The FCR of chicks fed feed-grade and extruded CSM plus 2% lysine at 21 d was significantly better than that of chicks fed feed-grade or extruded CSM alone. Abdominal fat pads (as a percentage of body weight) were significantly increased by the inclusion of CSM with or without the addition of lysine (P < or = 0.019). Liver, spleen, and heart weights were not affected by the presence of 20% CSM in the diet. The effects of CSM on plasma iron level was not consistent. Only in Experiment 1 did CSM cause a significant reduction in plasma iron. The hemoglobin contents and hematocrit values of blood from chicks fed diets with 20% CSM were not significantly different from those of the controls. The extrusion process reduced the free gossypol in CSM, but the total gossypol level was not changed, and chick performance was not improved. However, this study shows that, with adequate supplemental lysine, CSM can be used in broiler diets without a reduction in performance.

Acceptability of extrusion cooked cereal/legume weaning food supplements to Ghanaian mothers.

Six cereal/legume mixtures were developed with the aid of computer-assisted optimization software from cereal and legume staples indigenous to the West African sub-region. The mixtures had 45-50% maize, 35-40% decorticated cowpeas and either blanched peanuts or decorticated soybeans as a source of lipid and complementary amino acids. Three processing schemes involving roasting, amylase digestion and extrusion cooking were employed. The proportion of ingredients in each cereal/legume blend was based on meeting the nutrient requirement of the 0.5-0.9-year-old infant and cost considerations. Nutrient composition of the blends (proximate, amino acid, mineral and vitamin composition) indicated that these formulations were adequate nutritionally as weaning supplements (Mensa-Wilmot et al, 2000a,2000b). These formulations were evaluated by mothers of weanling children based on their preferences with respect to color, flavor, texture and willingness to purchase the product assessed. A total of 133 one-on-one interviews and 23 group discussions were conducted (involving 6-12 respondents) with selected Ghanaian women. The mothers found the convenience of a weaning food made from local staples that could be processed on village/market scale very attractive.

The normal foot.

The term "normal foot" has many different interpretations. This article reviews some of the ways in which the word "normal" has been used historically to describe the foot. Also discussed are the problems of attempting to determine what should constitute a normal foot and proposed criteria for distinguishing between the normal and the pathological.

1998 William J. Stickel Gold Award. The effects of extrinsic muscle forces on the forefoot-to-rearfoot loading relationship in vitro. Tibia and Achilles tendon.

The effects of muscular activity on the distribution of forces under the foot, as well as within the foot, are of great importance for determining the mechanisms of foot pathologies. Limited data exist concerning muscle forces during the gait cycle and the effects of muscle forces conveyed to the ground-reactive forces of the foot. The authors developed a cadaveric loading system to determine the effects of force applied to the Achilles tendon on the forefoot-to-rearfoot loading relationship in eight cadaveric specimens. The study indicated that, during axial loading of the tibia, force was inherently transferred from the rearfoot to the forefoot. However, the observed forefoot-to-rearfoot loading relationship did not match the predicted loading relationship from a rigid-body diagram, as would be observed in a class I lever. The results indicated that, as the force was increased on the Achilles tendon, the change in loads on the forefoot and rearfoot was not linear. Specimens with calcaneal inclination angles greater than 20 degrees demonstrated a more linear increase as compared with those with inclination angles less than 20 degrees.

Effect of processing on some properties of cowpea (Vigna unguiculata), seed, protein, starch, flour and akara.

Large brown eye Kano white cowpea (Vigna unguiculata) seeds were processed into three batches of flour by wetting, drying individually at 30, 80, and 120 degrees C, decorticating and dry milling. Starch was extracted from the cowpea seed and protein from the flour using water as solvent. The water-extractable proteins were purified by dialysis and analysed by electrophoresis. The cowpea flour was used to produce akara balls (fried paste). The microstructure of the cowpea cotyledon, flour, starch and akara crumb were examined with a scanning electron microscope (SEM). Electrophoretic separation revealed that some of the protein fractions from the sample extracted from 30 degrees C dried cowpea were absent in the sample extracted from the 80 degrees C and 120 degrees C dried cowpeas or their quantities had decreased. In the SEM study, no difference was observed in the microstructure of the three flour samples except in the size and shape of the starch granules and particles of protein and cell wall material. The starch granules from the cowpea dried at 120 degrees C had surface defects. Cavities occurred in the cotyledons of the 80 and 120 degrees C dried cowpea seeds, some starch granules, protein matrix and sometimes the entire cell contents were lost from the cell. The protein sheet in the akara crumb became thicker as temperature increased to 80 and 120 degrees C.

Functional motion of the medial column joints of the foot during propulsion.

Motion in the ankle, subtalar, midtarsal, and first metatarsophalangeal joints has been well documented. However, motion in the first metatarsocuneiform, the first cuneonavicular, and the first interphalangeal joint has not been addressed. Motion in these joints has not been documented because many believe that little motion occurs at these joints, and because of the difficulty in assessing motion at these joints. Using two-dimensional motion analysis, the authors present sagittal plane ranges of motion occurring in the first metatarsophalangeal joint, the first metatarsocuneiform joint, the medial cuneonavicular joint, and the first interphalangeal joint during the propulsive period of gait. This pilot study indicates that sagittal plane motion between the navicular and calcaneus and between the first metatarsal and first cuneiform are very mild and inconsistent. However, plantarflexion motion between the first cuneiform and the navicular is significant and comprises most of the plantarflexion motion of the first ray during propulsion. Motion in the first interphalangeal joint is slight during the first 80% of the propulsive period but shows slight-to-moderate dorsiflexion during the last 20% of the propulsive period of gait.

Cowpea flour: a potential ingredient in food products.

Cowpeas (Vigna unguiculata L. Walp) are an important grain legume in East and West African countries as well as in other developing countries. The U.S. is the only developed country producing large amounts of cowpeas. High protein (18 to 35%) and carbohydrate (50 to 65%) contents, together with an amino acid pattern complementary to that of cereal grains, make cowpeas potentially important to the human diet from a nutritional standpoint. Despite their potential as an inexpensive source of protein and energy, cowpeas are underutilized in the U.S. and other industrialized countries. A simple technology for preparing cowpea flour would stimulate increased consumption of this legume. This paper reviews the status of cowpea flour production technologies and uses of cowpea flour in various food products.

Use of peanut and cowpea in wheat-based products containing composite flours.

Cowpeas and peanuts are legumes of major dietary and economic importance. They are favored worldwide because of their palatability, contribution to nutritional status, and low cost as a protein source compared to animal protein. Flours processed from cowpeas and peanuts have unique physico-chemical and sensory properties when used in composite flour mixtures. Appropriate blends of cowpea and peanut flours to replace wheat flour in Chinese-type noodles, muffins, and tortillas were determined using modelling and optimization procedures. For noodles, 15% peanut flour and 8% cowpea flour supplementation produced an acceptable product with high protein content (21%). For wheat flour replacement in muffins, up to 43% cowpea and up to 44% peanut flours may be used. However, when wheat flour replacement is 50% or greater, cassava flour should comprise 56 to 72% of the blend with a few exceptions. In tortillas, 24% cowpea and 46% peanut flours produced products similar in quality characteristics to those made from 100% wheat flour. The systematic approach used in these studies is more efficient than the traditional substitution method to optimize sensory qualities of wheat-based products containing composite flours.