Demographic analyses of organophosphate-resistant and susceptible strains of greenhouse whitefly, Trialeurodes vaporariorum, on three cotton cultivars

Laboratory experiments were conducted using organophosphate-resistant and susceptible strains of greenhouse whitefly, Trialeurodes vaporariorum Westwood, to assess age-specific vital rates in individually-held adults, and development and survival in preadults on three cotton cultivars at 27±1 °C, 50±10% RH, and a photoperiod of 16:8 (L:D). Female whiteflies lived longer than males, with a maximum life expectancy of 29 days. Heaviest egg laying occurred at ages between 7 and 18 days when individual whiteflies laid > 10 eggs/day. Greenhouse whitefly populations doubled weekly, with stable age distribution of 63% eggs, 28% larvae, 5% pupae, and 4% adults. Analysis of various life history parameters that combine aspects of survival, developmental rates, and fecundity indicated no consistent differences in reproductive fitness between the two greenhouse whitefly strains. Of the three cotton cultivars tested, Pima S-6 was most susceptible, Acala SJ-2 was intermediate and Gumbo 500 was most resistant to greenhouse whitefly. Resistance of Gumbo 500 was expressed as slower developmental rates, reduced survival to adulthood, lower reproductive rates, and lower intrinsic rate of increase.     

Influence of Hairiness ofGerbera jamesoniiLeaves on the Searching Efficiency of the ParasitoidEncarsia formosa

To characterize the relationship between the leaf surface ofGerbera jamesoniiHooker cultivars and the searching behavior of the parasitoidEncarsia formosaGahan on a leaf, the trichome density and shape were described, and the walking behavior was quantified. Leaf hair density varied from 80 to more than 1000 trichomes/cm²and the hair shape varied from single erect trichomes to tapestries of entangled trichomes above the leaf surface. The walking activity, speed, and pattern of the parasitoid were tested on leaves with different hair density and shape. In spite of the large differences in leaf surface structure, the walking activity was similar and around 75% on most cultivars. The walking speed was between 0.2 and 0.3 mm/s on all cultivars and was not significantly different from the speed on tomato. On hairless sweet pepper leaves the walking speed is much higher (0.73 mm/s), so the hairs onGerberaleaves do hamper parasitoid females and result in a strong reduction of the walking speed, but the variation in hair density and shape onGerberadoes not lead to differences in walking activity, pattern, and speed. It appears that the hairs ofGerberaare less of an obstacle forE. formosathan the stiff, large hairs occurring in a high density on cucumber, where the walking speed of the parasitoid is less than 0.2 mm/s. A rise of temperature of 5°C gave a significantly higher walking speed (0.39 mm/s) ofE. formosafemales on all cultivars tested. The relative straightness of the walking track was high and the same on all cultivars. Consequences of the results of the searching behavior ofE. formosaonG. jamesoniicultivars are discussed with respect to other host plants. As parasitoid walking speeds are the same onGerberaand tomato, and whitefly reproduction is also similar on these two host plants, we conclude that biological control of whiteflies onGerberais a realistic option. This conclusion is confirmed by the strong increase of commercial biological control onGerberawhich occurred during the past 5 years.     

Life on a deadly trap: Buckleria paludum,a specialist herbivore of carnivorous sundew plants,licks mucilage from glands for defense

Caterpillars of Buckleria spp. (Lepidoptera: Pterophoridae) have a unique feeding habit of eating trap leaves of carnivorous sundew plants (Drosera spp.). We observed the foraging behavior of Buckleria paludum on trap leaves of Drosera spp. and discussed how the moth species avoided being caught by trap leaves. In 81.5% (66/81) of encounters with glandular hairs on adaxial surfaces of Drosera trap leaves, B. paludum larvae licked mucilage and crawled on the processed hairs. The frequency of licking mucilage was significantly higher than the frequency of other behaviors such as eating glandular hairs, chewing bases of them without eating and ignoring when encountering secreted mucilage. Licking mucilage enables the caterpillars to move safely on trap leaves and prevents bending of glandular hairs.     

Bemisia tabaci (Hemiptera: Aleyrodidae) biotype B colonisation and leaf morphology relationships in upland cotton cultivars

Cultivars of upland cotton, Gossypium hirsutum L., are widely grown throughout the world for fibre production. They are also good reproductive hosts for Bemisia tabaci (Gennadius) biotype B. We studied the relationships between cotton leaf morphology and whitefly population densities in eight United States Deltapine and six Australian cotton cultivars and breeding lines at Holtville, California, in 1996. Results showed that okra-leaf cultivars and lines were colonised with fewer whitefly adults, eggs and nymphs compared to normal-leaf cultivars. The distance from underleaf surfaces of cotton leaves to the centres of nearest minor vascular bundles was negatively correlated with whitefly adult, egg and nymphal densities on leaves for all genotypes with the exception of the Australian breeding line 89013–114. Our results suggest that okra-leaf and distance from underleaf surfaces to the centre of nearest minor vascular bundles of cotton leaves are genetic traits that have potential for breeding whitefly-resistant upland cotton cultivars.     

Differences in distribution and performance of two sap-sucking herbivores on glandular and non-glandular Datura wrightii

1. Datura wrightii Regel (Solanaceae) is polymorphic with regard to trichome type. Some plants are densely covered with short, non-glandular trichomes, whereas other plants in the same populations possess glandular trichomes that excrete a sticky exudate. The hypothesis that glandular trichomes enhance resistance to all small insect herbivores is evaluated.
2. Field censuses in four southern Californian D. wrightii plant populations revealed that glandular plants are indeed resistant to whitefly spp. (Homoptera: Aleyrodidae). Whiteflies are almost exclusively found on non-glandular plants. In contrast, Tupiocoris notatus (Distant) (Heteroptera: Miridae), another sap-sucking herbivore of similar body size, is found predominantly on plants with glandular trichomes.
3. Laboratory experiments showed that whiteflies are unable to colonize glandular D. wrightii phenotypes. After the whitefly adults had landed on the leaves of these plants, they were trapped in the exudate and died.
4. Tupiocoris notatus adults, on the other hand, laid significantly more eggs on glandular plants. The presence of the exudate was shown to be the cue that determined their choice of glandular plants.
5. In no-choice experiments, T. notatus nymphs reared on glandular plants had significantly higher survival rates and had shorter developmental periods than those raised on non-glandular plants. This, combined with the higher oviposition rates, resulted in higher T. notatus population growth rates on glandular plants than on non-glandular plants.
6. Glandular trichomes are not therefore a universal protection against small herbivores. Differences in distribution over the two plant types within the natural herbivore guild on D. wrightii may, among other selection pressures, contribute to the maintenance of the observed trichome polymorphism.     

Variable responses of tuber moth to the leaf trichomes of wild potatoes

This study examines the response of tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), during the initial stages of attack, to variability in trichome density and composition on foliage of Solanum berthaultii (Hawkes) and Solanum tarijense (Hawkes) (Solanaceae). Solanum berthaultii bears two types of glandular trichome (type A and type B) that together reduced oviposition by the moth. Females were often completely deterred from ovipositing on foliage with >300 trichomes per cm². In contrast, neonate establishment on S. berthaultii was generally positively related to trichome densities, indicating that trichomes may be a poor defense against P. operculella when the moth oviposits in soil and neonate larvae select the host plant. Solanum tarijense has only one type of glandular trichome (type A) and eglandular hairs. Most eggs were deposited on the adaxial leaf surfaces that had lower trichome densities. Although the density of type A trichomes was negatively related to oviposition, high densities of hairs on the abaxial and adaxial leaf surfaces appeared to stimulate oviposition, leading to stronger positive relations between hair densities and oviposition. Larvae generally established on the abaxial surface where hair densities were greatest. Relationships between the abaxial densities of leaf hairs and neonate establishment on S. tarijense were positive. The results indicate that the responses by P. operculella to the types and density of trichomes are complex. Whereas type A and type B trichomes may act synergistically to reduce oviposition by the moth, leaf hairs do not defend against oviposition and neither leaf hairs nor type A and B trichomes reduce neonate establishment by this herbivore species.     

Influence of trichomes on attractiveness and ovipositional preference of Bemisia tabaci (Genn.) B biotype (Hemiptera: Aleyrodidae) on tomato genotypes

Brazil is one of the world's largest tomato producer, but considerable part of the production is lost due to the attack of Bemisia tabaci (Genn.) B biotype. Resistant germoplasm plants can be an important method for B. tabaci control in integrated pest management approaches. The attractiveness and ovipositional preference of B. tabaci for 17 tomato genotypes were evaluated in a free-choice test. Trials were set up in a randomized block design with ten replicates. Each replicate (one tomato plant per pot) was placed in a cage (80 x 50 x 50 cm) and infested with 1,000 adults during four days. Linear correlation tests were applied between the number of insects and eggs and number of trichomes in each tomato genotype. LA716, LA444-1 and PI134418 genotypes were the least attractive, while the 'Santa Clara' was the most attractive; PI134417 trapped the largest number of adults. LA716 genotype (4.1 eggs/leaflet and 2.1 cm2/eggs per leaflet) was the least preferred for whitefly oviposition; NAV1062, 'Fanny', LA1335, 'Santa Clara' and IAC294 were the most preferred genotypes. The glandular trichomes density was negatively correlated with whitefly's attractiveness and oviposition per leaflet and per leaf, and positively with the number of trapped insects. The non-glandular trichomes density was negatively correlated with the number of trapped insects and positively with whitefly's oviposition per cm2/leaflet andper cm2/leaf. LA716 had high antixenosis level (ovipositional nonpreference) toward B. tabaci B biotype related with type IV glandular trichome.     

Yellow sticky trap catches of parasitoids of Bemisia tabaci (Hemiptera: Aleyrodidae) in vegetable crops and their relationship to in-field populations

We examined the relationship of yellow sticky trap captures of Bemisia tabaci (Gennadius) biotype B parasitoids to the local population of parasitoids as measured by leaf samples of parasitized whiteflies and mass release of parasitoids. Traps were placed in experimental collard and cowpea field plots in Charleston, SC, and in commercial organic fields of spring cantaloupe and watermelon in the Imperial Valley, CA. The exotic parasitoid Eretmocerus emiratus Zolnerowich and Rose was released in Imperial Valley fields to ensure parasitoid populations would be present. Bemisia adults were trapped in the greatest numbers on the upper surface of horizontally oriented sticky traps in melon fields. In contrast, the lower trap surfaces consistently captured more Eretmocerus than upper surfaces. Female parasitoids were trapped in greater numbers than males, especially on the lower trap surfaces. Progeny of released exotic Eretmocerus greatly outnumbered native E. eremicus Rose and Zolnerowich and Encarsia spp. on traps. Throughout the season, the trend of increasing numbers of Eretmocerus on traps parallelled the increase in numbers of whiteflies. Over the season, 23-84% of all B. tabaci fourth instars were visibly parasitized by Eretmocerus. The numbers of Eretmocerus caught by traps in cantaloupe were similar in trend to numbers on leaf samples in melons, but not with those in watermelon, where whitefly populations were lower. Parasitoid numbers were low in collard and cowpea samples, and no trend was observed in numbers of parasitoids captured on traps and numbers on leaves for these two crops. Overall, there were no significant correlations between sticky trap catches of parasitoids and numbers of parasitized whiteflies on leaf samples in any test fields. Nevertheless, sticky traps placed within crops may be useful for observing trends in whitefly parasitoid populations at a particular site and for detecting parasitoids at specific locations.     

Foraging Behavior of the Parasitoid Encarsia formosa on Gerbera jamesonii Leaves

Insight into the foraging behavior of the parasitoid Encarsia formosa Gahan for whitefly hosts was gained by continuous observation of individual parasitoids on leaves of the ornamental plant Gerbera jamesonii, until females left the leaf. Comparison of the parasitoid behavior on three cultivars gave similar results. Mean searching time on uninfested G. jamesonii leaves of three cultivars was 1 h 30 min and the mean percentage of walking activity of the total observation time on those cultivars was 61%. Both parameters were not influenced by different leaf structures of Gerbera cultivars. Encounters with hosts arrested the parasitoids on the leaves. The walking activity and the percentage of host encounters that resulted in an oviposition decreased with decreasing egg load of the parasitoid. In comparison with tomato, where biological control of whiteflies is successful, only minor differences in the foraging behavior occur, except for the residence time of females, which was about three to four times longer on G. jamesonii leaves, but these leaves are about seven times larger than tomato leaves. The facts that (1) the foraging behavior of E. formosa on G. jamesonii is independant of the cultivar and (2) the foraging behavior is, in many aspects, similar to that on tomato suggest that biological control of whitefly on this ornamental plant is a potential option.     

Population suppression of Bemisia tabaci (Hemiptera: Aleyrodidae) using yellow sticky traps and Eretmocerus nr. rajasthanicus (Hymenoptera: Aphelinidae) on tomato plants in greenhouses

We conducted three experiments for management of Bemisia tabaci (Gennadius) biotype ‘B’ on tomatoes under greenhouse conditions: (i) vertically placing yellow sticky cards either parallel or perpendicular to tomato rows at a rate of 1 per 3‐m row; (ii) releasing Eretmocerus sp. nr. rajasthanicus once at 30 adults/m² in the high whitefly density greenhouses (> 10 adults/plant), or twice at 15 adults/m² at a 5‐day interval in the low whitefly density greenhouses (< 10 adults/plant); and (iii) using combinations of yellow sticky cards that were placed vertically parallel to tomato rows and parasitoids released once at 30/m² in high whitefly density greenhouses or twice at 15/m² at a 5‐day interval in low whitefly density greenhouses. Our data show that yellow sticky cards trapped B. tabaci adults and significantly reduced whitefly populations on tomato. The yellow sticky cards that were placed parallel to tomato rows caught significantly more whitefly adults than those placed perpendicular to tomato rows on every sampling date. In the treatment where parasitoids were released once at 30/m² in high whitefly density greenhouses, the number of live whitefly nymphs were reduced from 4.6/leaf to 2.9/leaf in 40 days as compared with those on untreated plants on which live whitefly nymphs increased from 4.4/leaf to 8.9/leaf. In the treatment where parasitoids were released twice at 15/m² in low whitefly density greenhouses, the numbers of live nymphs of B. tabaci on tomato leaves were reduced from 2.1/leaf to 1.7/leaf in 20 days as compared with those on untreated plants on which numbers of live nymphs of B. tabaci increased from 2.2/leaf to 4.5/leaf. In the treatment of yellow sticky cards and parasitoid release once at 30/m² in high whitefly density greenhouses, the numbers of live nymphs of B. tabaci on tomato leaves were reduced from 7.2/leaf to 1.9/leaf, and in the treatment of yellow sticky cards and parasitoid release twice at 15/m² at a 5‐day interval at low whitefly density, the numbers of live nymphs of B. tabaci on tomato leaves were reduced from 2.5/leaf to 0.8/leaf; whereas the numbers of live nymphs of B. tabaci on untreated plants increased from 4.4/leaf to 8.9/leaf. An integrated program for management of B. tabaci on greenhouse vegetables by using yellow sticky cards, parasitoids and biorational insecticides is discussed.     

Attachment ability of the beetle Chrysolina fastuosa on various plant surfaces

To study the role of different structures of a plant surface preventing insect attachment, a variety of plant surfaces were screened. Attachment ability of the beetle Chrysolina fastuosa Scop. (Coleoptera, Chrysomelidae) was measured on 99 surfaces among them smooth, hairy, felt-like, waxy, and glandular ones of three plant organs (stems, leaves, fruits) of 83 plant species belonging to 45 families. Insects attached successfully to smooth, hairy, and felt-like substrata. These surface types did not effect the further attachment of C. fastuosa, indicating the adhesive system remained intact after contacting these substrata. However, the beetles could not attach properly to surfaces covered with wax crystalloids or glandular hairs. In most experiments on pruinose plant substrata, no influence of the surfaces on the subsequent attachment ability of insects was observed. Only in one case (the stem of Acer negundo), was such an impairment recorded, but recovery of attachment ability was fast. Crystalloids of this plant species probably temporarily disable function of tenent setae of C. fastuosa. Four hypotheses, explaining anti-adhesive properties of plant surfaces, covered with wax crystalloids are proposed. A plant surface with glandular trichomes disabled the attachment system of the beetle for a long time. Secretions of trichomes probably glue tenent setae together making further attachment impossible.     

Effect of imidacloprid on the sivlerleaf whitefly, Bemisia argentifolii Bellows and Perrring (Homoptera: Aleyrodidae), and whitefly parasitism

Bioassays were conducted under greenhouse conditions to determine the effect of imidacloprid on adult and nymphal stages of the silverleaf whitefly, Bemisia argentifolii Bellows and Perring, and parasitism by Encarsia formosa (Gahan). A flowable formulation (24Oglitre^-1) of imidacloprid at six rates (0.09, 0.04 and 0.02 g a.i. litre^-1 pot volume for experiments 1 and 2; 0.009, 0.004, and 0.002 g a.i. litre^-1 pot volume for experiment 3) was evaluated. After a 48 h exposure to treated plants, high mortality of adult whitefly (>94%) was observed. Adults exposed to poinsettias treated 150 days earlier also had significantly greater mortality (>79%) than the adults on control plants. When exposed to treated plants for only 6 h, >65% of adults were killed. All three rates of imidacloprid caused >97% mortality of immature whiteflies by day 19. When treated plants were continually exposed to adult whiteflies, immature mortality was 100% for the three higher rates of imidacloprid up to and including 88 days after treatment. During the same time, emerging adults were reduced significantly. Immatures reinfested on plants treated 161 days earlier, incurred 80% mortality at the higher rate 0.09 g a.i. litre^-1 pot volume and 38% mortality at 0.02 g a.i. litre^-1 pot volume. At lower treatment rates, results varied. At 0.009 g a.i. litre^-1 of pot volume, mean percentage whitefly mortality (65%) 25 days after treatment was significantly higher than the controls; however, whitefly mortality at 0.004 and 0.002 g a.i. litre^-1 pot volume was not significantly different from controls or plants treated with the higher rate. Parasitoids could develop to the adult stage on whiteflies infesting imidacloprid treated plants. Parasitism occurred at low levels (< 10%), doe to high levels of whitefly mortality on treated plants. No phytotoxicity was observed for any treatment throughout the length of the trials that lasted through flowering.     

Evaluation of the lady beetle,Serangium parcesetosum for control of Bemisia tabaci on greenhouse eggplant in the Mediterranean region

Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) is one of the most serious pests of greenhouse crops. It is mainly controlled by chemical means, requiring some 10–12 sprays during the average growing season in Turkey. There is growing interest in finding alternatives to pesticides for control of B. tabaci in greenhouse crops because this heavy pesticide usage disrupts biocontrol and leads to rapid build-up of insecticide resistance in the pest. In our study, the control of B. tabaci on greenhouse eggplants was evaluated following releases of the lady beetle Serangium parcesetosum Sicard (Coleoptera: Coccinellidae). In cage experiments, four adults per plant were introduced and, within 3–4 weeks, resulted in 97 and 98% reductions in whitefly populations in 2004 and 2005, respectively. In a large plot experiment, two adults per plant were released only one time. Beetle larvae were observed through 2–9 weeks after release. The density of whitefly in large plot receiving beetle adults showed fluctuations to a level lower than in control plot receiving no beetle in 2004 and 2006. Further study is needed to develop new managing strategies in biological control of B. tabaci with S. parcesetosum in protected culture.     

Susceptibility of strawberry cultivars to the vine weevil Otiorhynchus sulcatus (Coleoptera: Curculionidae)

Abstract 1 The feeding preference of vine weevil, Otiorhynchus sulcatus (Fabricius), adults for foliage from 21 commercial cultivars of strawberries is investigated using binary choice tests with leaf disks, using ‘Honeoye’ as a standard against which all other cultivars are compared. ‘Delmarvel’, ‘Idea’, ‘Lester’, ‘Primetime’ and ‘Seneca’ are not preferred. 2 Variation in leaf nitrogen content is correlated with feeding preference, but does not explain all the variation, because outliers exist for both preferred and nonpreferred cultivars. 3 Removal of leaf hairs with adhesive tape permits their role in deterrence to be evaluated. Eight of the 21 cultivars have deterrent leaf hairs. Paradoxically, some highly preferred cultivars (e.g. ‘Latestar’ and ‘Tristar’) have deterrent leaf hairs, and four of the five nonpreferred cultivars lack significantly deterrent leaf hairs. 4 The 21 tested cultivars do not differ in their suitability for vine weevil larval development. 5 Differences in cultivar susceptibility to vine weevil in the field may involve interactions between the palatability and nutritional value of foliage, which influence fecundity and egg placement, and the tolerance of strawberry plants to larval feeding, determined by root biomass. The nonpreference traits found in the foliage of commercial cultivars of strawberry are present by chance. Accordingly, further selective breeding to enhance strawberry varietal tolerance to vine weevils may be possible.     

Anti-herbivore structures of Paulownia tomentosa: morphology, distribution, chemical constituents and changes during shoot and leaf development

Background and Aims: Recent studies have shown that small structures on plant surfacesserve ecological functions such as resistance against herbivores.The morphology, distribution, chemical composition and changesduring shoot and leaf development of such small structures wereexamined on Paulownia tomentosa. Methods: The morphology and distribution of the structures were studiedunder light microscopy, and their chemical composition was analysedusing thin-layer chromatography and high-performance liquidchromatography. To further investigate the function of thesestructures, several simple field experiments and observationswere also conducted. Key Results: Three types of small structures on P. tomentosa were investigated:bowl-shaped organs, glandular hairs and dendritic trichomes.The bowl-shaped organs were densely aggregated on the leavesnear flower buds and were determined to be extrafloral nectarines(EFNs) that secrete sugar and attract ants. Nectar productionof these organs was increased by artificial damage to the leaves,suggesting an anti-herbivore function through symbiosis withants. Glandular hairs were found on the surfaces of young and/orreproductive organs. Glandular hairs on leaves, stems and flowerssecreted mucilage containing glycerides and trapped small insects.Secretions from glandular hairs on flowers and immature fruitscontained flavonoids, which may provide protection against someherbivores. Yellow dendritic trichomes on the adaxial side ofleaves also contained flavonoids identical to those secretedby the glandular hairs on fruits and flowers. Three specialtypes of leaves, which differed from the standard leaves inshape, size and identity of small structures, developed nearyoung shoot tips or young flower buds. The density of smallstructures on these leaf types was higher than on standard leaves,suggesting that these leaf types may be specialized to protectyoung leaves or reproductive organs. Changes in the small structuresduring leaf development suggested that leaves of P. tomentosaare primarily protected by glandular hairs and dendritic trichomesat young stages and by the EFNs at mature stages. Conclusions: The results indicate that P. tomentosa protects young and/orreproductive organs from herbivores through the distributionand allocation of small structures, the nature of which dependson the developmental stage of leaves and shoots.     

Glandular Trichomes on Alfalfa Impede Searching Behavior of the Potato Leafhopper Parasitoid

New cultivars of alfalfa, Medicago sativa L., have been released with glandular trichomes for resistance to potato leafhopper, Empoasca fabae (Harris). Yet, the impact of the glandular trichomes on the primary natural enemy of the leafhopper, Anagrus nigriventris Girault, is unknown. We compared the host searching behavior of the egg parasitoid on four alfalfa clones varying in trichome characters. Female wasps were videotaped on Ranger, a susceptible clone with relatively sparse trichomes, B14, a resistant clone with dense but nonglandular trichomes, and FG12 and FG18, two resistant clones with glandular trichomes. Although the number of leafhopper eggs per stem exposed to wasps did not significantly differ among the four clones, the frequency of foraging and total foraging time were less on the two clones with glandular trichomes than on the two clones with nonglandular trichomes. In addition, an analysis of covariance demonstrated that, although the number of ovipositional probes increased with egg density on a stem, the number of probes on stems with glandular trichomes was significantly less than that on stems without glandular trichomes. The allocation of time by wasps among drumming, probing, and grooming behaviors was similar among the clones. Wasps tended to fly off of clones with glandular trichomes more often than off of clones with nonglandular trichomes. This study suggests that cultivars with glandular trichomes may interfere with host searching by A. nigriventris.     

Leaf micromorphology and leaf glandular hair ontogeny of Myoporum bontioides A. Gray

Myoporum bontioides A. Gray (Myoporaceae), a red list plant in Japan, is restricted to only a few East Asian countries like China, Japan and Taiwan, associated to some true mangroves. The leaf is isolateral and has a thick cuticle; stomata are anomocytic, sunken and have a beak‐shaped cuticular outgrowth at the inner and outer side of the stomatal pore (ledges); profuse glandular hairs are scattered on both leaf surfaces of young leaves. The mesophyll is compact with palisade and spongy parenchyma cells in the young stage, but at maturity profuse intercellular spaces can be observed. Secretory ducts occur in young leaves. Pear‐shaped glandular hairs protrude from the epidermal layer. Hair primordia are well distinct by their larger size and undergo divisions to produce two laterally placed basal cells, two stalk cells and four radiating terminal cells. The cuticle layers of the terminal cells are often separated from the cell wall to form a space, in which ions accumulate for excretion. Inner walls of the basal cells are connected with the mesophyll. Though ontogeny and structure of glandular hairs have resemblance to typical mangroves, considering leaf micromorphology, this plant is better termed as “mangrove associate” instead of “true mangrove”. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Trichome morphology provides phylogenetically informative characters for Tremandra, Platytheca and Tetratheca (former Tremandraceae)

Summary Trichomes of Tremandra R.Br. ex DC., Platytheca Steetz and Tetratheca Sm. (Elaeocarpaceae, former Tremandraceae), together with two outgroup species of Elaeocarpus L., are illustrated using scanning electron microscopy, and their distribution on various plant organs is documented. Various trichomes types were identified that relate taxa: simple hairs, stellate hairs, short glandular trichomes, long glandular trichomes, and three forms of tubercules. Both outgroup and ingroup taxa have simple hairs. Stellate hairs are confirmed as unique to Tremandra. Prominent and sculptured multicelled tubercules, some bearing a stout hair, are characteristic of Platytheca. Smaller multicelled tubercules occur in both Platytheca and Tetratheca, except for the Western Australian taxon Te. filiformis Benth. (possibly plesiomorphic). Unicellular tubercules (papilla) characterise two species of Tetratheca. Short glandular trichomes, usually found on the ovary, also occur in both of these genera but not in all species (possibly secondary losses), while long glandular trichomes, usually on stems and leaves, occur only in some groups of Tetratheca. Within Tetratheca, Western Australian taxa that have five-merous flowers fall into three ‘groups’: seven species (together with one from South Australia) that have short glandular trichomes but no long glandular trichomes; six species that have long glandular trichomes but no short glandular trichomes; and four species that have both trichome types. All other species of Tetratheca have four-merous flowers and form two ‘groups’: 12 eastern species (including one from South Australia) that have both short glandular trichomes and long glandular trichomes; 4 western species and six eastern species that lack short glandular trichomes. On the basis of these characters, a phylogenetic hypothesis for the three genera is presented.     

Pedestal hairs of the ant Echinopla melanarctos (Hymenoptera, Formicidae): morphology and functional aspects

The South East Asian arboreal Formicine Echinopla melanarctos, as well as some other members of this genus possess a cuticular structure unique in ants, the pedestal hairs. In E. melanarctos, about 700 pedestal hairs are situated on the dorsal and lateral surfaces of the head, the alitrunk, the petiole and the gaster. They are arranged in a polygon-like figuration. On the summit of each of the up to 200-μm high pedestals, a single central hair inserts. This hair (up to 500-μm long) is innervated by a single bipolar mechanosensitive sensory cell. The lumen of each tube-like pedestal contains (1) epithelial cells (2) the sensory cell and the auxiliary cells of the central hair and (3) the long efferent ductules of up to ten isolated bicellular glandular units. Each glandular unit is composed of a secretory glandular cell and a duct cell, all of which are located at the base of a pedestal. The cytoplasm of a glandular cell contains a well-developed end apparatus and is characterised by stacks of smooth and granular endoplasmic reticulum, numerous polyribosomes, a lot of mitochondria and some up to 5-μm large secretory vesicles. The secretion of the gland cells is released on the apex of the pedestal wall via small pores. Approximately 30 μm below their summit, some pedestals possess additionally (up to six) mechanosensitive hairs that are arranged ray-like. We suppose that the pedestal hairs are important in nest-space protection and find that only in ants with high pedestals on the head (Echinopla melanarctos and Echinopla pallipes), the compound eyes are stalked thus overtopping the pedestals.     

细叶益母草(Leonurus sibiricus)叶表面腺毛多样性及发育形态学研究

本文研究了分布在细叶益母草（Ｌｅｏｎｕｒｕｓｓｉｂｉｒｉｃｕｓ） 叶表面三种腺毛的发育过程,在此基础上,对２细胞头状腺毛、４细胞头状腺毛和８细胞盾状腺毛的多样性特征进行了讨论