Relationships between the occurrence of misshapen fruit on late-season strawberry in the United Kingdom and infestation by insects, particularly the European tarnished plant bug, Lygus rugulipennis

In experiments in which the European tarnished plant bug, Lygus rugulipennis, was caged on the developing flowers or young fruits of strawberry, the insects caused malformation of the fruits. Another species of capsid, Plagiognathus chrysanthemi, caused similar damage; this species is less numerous than L. rugulipennis on late-season crops of strawberry in UK. Other insects which sometimes occur in large numbers in the flowers of late-season strawberry, i.e. various species of thrips and pollen beetles, did not cause fruit malformation in caging experiments, though thrips sometimes caused discoloration of the fruit. In field experiments where numbers of L. rugulipennis were reduced by the use of insecticides, the amount of misshapen fruit was reduced greatly compared to untreated plots. Correlations between the numbers of L. rugulipennis present at the early stages of fruit development and damage scores for fruit deformity were highly significant. This capsid is likely to be the major cause of fruit malformation in late-season crops of strawberry in the UK.     

A new plant-animal mutualism involving a plant with sticky leaves and a resident hemipteran insect

We report on a new plant-animal mutualism in which the plant Roridula gorgonias, first suspected by Darwin (1875) to be carnivorous, is, at least in part, indirectly carnivorous. This plant has sticky leaves which trap many insects but it has no digestive enzymes. Instead, trapped invertebrates are rapidly consumed by a hemipteran Pameridea roridulae, only found on this plant. However, evidence from ¹⁵N experiments suggests that R. gorgonias does derive significant amounts of nitrogen from trapped prey, apparently via exudations of P. roridulae.     

An experimental test of the defensive role of sticky traps in the carnivorous plant Pinguicula moranensis (Lentibulariaceae)

It has been sustained that the sticky traps present in some carnivorous plants could have evolved from ancestor species bearing leaves covered with secreting glands formerly associated with a defensive function. In this study, we evaluated the interaction of the carnivorous plant Pinguicula moranensis with its insect herbivores to assess the defensive role of the glandular trichomes. Firstly, we estimated the standing levels of insect herbivory in field conditions. We also evaluated the response of herbivore insects to the removal of the secreting glands from the leaves of P. moranensis in field and laboratory conditions. The mean damage was 1.61%, and half of the sampled plants showed no damage. The low level of herbivory in the field suggests that P. moranensis has an efficient defense ability. In the field experiment, after 25 d of exposure to natural damage, treated glandless plants received 18 times more damage than control plants. In the laboratory, the consumption of glandless tissue was three times higher during a 6 h evaluation period. Overall, our results provide evidence that secreting trichomes in Pinguicula are not only associated with prey capture but also have a defensive role. The defensive function could have favored the evolution of the sticky traps, the most extended prey‐capture strategy among carnivorous plants.     

The movement of involucral bracts of Syngonanthus elegans (Eriocaulaceae-Poales): Anatomical and ecological aspects

Syngonanthus elegans flowers are distributed in capitula whose involucral bracts open and close in a diurnal rhythm. The anatomy of these bracts was studied to understand how such movements occur and how it influences reproductive ecology of the species. The involucral bracts have a single layered epidermis composed of thick-walled cells on the abaxial surface, which are responsible for the movement. Since they are hygroscopic, these cells swell when they absorb water from the surrounding environment, causing the bracts to bend and the capitula to close. In natural conditions, the capitula open by day, when temperature increases and the relative air humidity decreases, and close at night, when temperature decreases and the relative air humidity increases. The involucral bracts may thus protect the flowers from abiotic factors, exposing them only at the time of the day when temperature is higher and insects are more active, favoring pollination by small insects. The closed capitula do not only protect the flowers, but they also function as a shelter for floral visitors as Brachiacantha australe (Coccinellidae) and Eumolpini sp. (Chrysomelidae). These small Coleoptera pollinate the flowers of S. elegans during the day and remain within the closed capitula during the night, in a possible mutualistic relationship.     

Hoverflies can sense the risk of being trapped by carnivorous plants: An empirical study using Sphaerophoria menthastri and Drosera toyoakensis

Carnivorous plants are major predators of small insects in some habitats. Because traps of carnivorous plants are serious threats for small insects, it is probable to evolve a mechanism to sense a cue of carnivorous plants and avoid being trapped. However, such a sensing behavior of small insects has never been described. Here we report that a hoverfly species Sphaerophoria menthastri, a major pollinator species of carnivorous sundew Drosera toyoakensis, exhibits a behavior to sense a cue of trap leaves and avoids landing there. In a quadrat (5?m?×?5?m) where D. toyoakensis and other non-carnivorous plant species co-occur, we observed behaviors of hoverflies approaching D. toyoakensis and other plants. The numbers of approaches to trap leaves, flowers of D. toyoakensis, flowers of non-carnivorous Lysimachia fortunei and leaves of Poaceae and Cyperaceae were 9, 60, 52 and 54, respectively, and the numbers of landings to those four organs were 2, 55, 49 and 49, respectively. When S. menthastri approached trap leaves, almost all individuals successfully avoided landing there by 1 or 2 hesitation behaviors. These findings suggest that S. menthastri can sense the cue of trap leaves during an approach.     

Prey spectra of aquatic Utricularia species (Lentibulariaceae) in northeastern Germany: The role of planktonic algae

The carnivorous bladderworts (Utricularia) possess complicated suction traps. Remarkably, information on the prey trapped is relatively sparse. We have conducted a detailed survey on the prey spectra found in traps of selected aquatic bladderworts (U. australis, U. vulgaris) occurring in ponds in northeastern Germany. A close examination of more than 200 traps revealed cladocerans, copepods, rotiferas, ciliates and insect larvae as being common prey.Of particular interest was the considerable amount of phytoplankton (i.e. algae, cyanobacteria) found in the traps. In total, more than 160 algae species (among others, Kirchneriella lunaris, Scenedesmus quadricauda and S. acuminatus) belonging to more than 50 genera were present, with Chlorophyceae being dominant. The role of the vegetarian diet for nutrient supply of bladderworts is discussed.     

Three new species of Dendropanax (Araliaceae) from Bahia, Brazil

Three new species of BrazilianDendropanax from the rain forests of Bahia state are described and illustrated.Dendropanax amorimii, endemic to the rain forests near Boa Nova, in southern Bahia, is characterized by compound umbellate inflorescences with elongated primary branches each having a proximal whorl of bracts, and by leaves with well-developed tertiary venation.Dendropanax bahiensis, endemic to the Atlantic rain forests of southern Bahia, is distinguished by its large and membranous leaves with reddish schizogenous glands on the abaxial surface and by the reduced and branched inflorescences with short-pedicellate flowers and large fruits.Dendropanax geniculatus, an endemic species from the “matas de grotão” of Serra da Chapadinha, Chapada Diamantina, is characterized by simple and usually geniculate inflorescences bearing long-pedicellate flowers and fruits.     

Light and electron microscopy study of the salivary glands of the carnivorous opisthobranch Philinopsis depicta (Mollusca, Gastropoda)

Cephalaspideans are a group of opisthobranch gastropods that comprises carnivorous and herbivorous species, allowing an investigation of the relationship between these diets and the morphofunctional features of the salivary glands. In this study, the salivary glands of the carnivorous cephalaspidean Philinopsis depicta were observed by light and electron microscopy. The secretory epithelium of these ribbon-shaped glands is formed by ciliated cells, granular cells and cells with apical vacuole. In ciliated cells the nucleus and most cytoplasmic organelles are located in the wider apical region and a very thin stalk reaches the base of the epithelium. These cells possess significant amounts of glycogen. Granular cells are packed with electron-dense secretory granules and also contain several cisternae of rough endoplasmic reticulum and Golgi stacks. The other type of secretory cell is mainly characterized by the presence of a large apical vacuole containing secretion. These cells possess high amounts of rough endoplasmic reticulum cisternae and several Golgi stacks. Vesicles with peripheral electron-dense material are also abundant, and seem to fuse to form the apical vacuole. The available data point out to a significant difference between the salivary glands of carnivorous and herbivorous cephalaspidean opisthobranchs, with an intensification of protein secretion in carnivorous species.     

A field study on the red-bellied tamarin,Saguinus l. labiatus,in Bolivia

A 5-month field study was conducted on red-bellied tamarins,Saguinus labiatus labiatus, in the Pando Department of northern Bolivia. Group sizes ranged from 5 to 10 animals, and each group associated with a group of saddle-backed tamarins,Saguinus fuscicollis weddelli. Members of three groups were trapped and marked and data were collected by radiolocation. The average range size used over 10 days was 19 ha. On average the groups entered about 29% of their range each day and had a mean daily path length of about 1487 m. The groups used a number of different sleeping sites within their ranges. They fed on a variety of different fruits and also on nectar from flowers, resin, and insects. Areas within the home range which were used significantly more than expected were generally those in which one or more of the following existed: a sleeping site, an intergroup encounter site, or a site where the group took shelter during an extended period of heavy rain.     

桑叶西番莲——中国西番莲科植物新归化种

外来物种的归化和入侵对全球环境和社会发展造成了严重影响,已成为当今各国生物多样性管理和生态保护中所面临的全球性问题。我国是遭受外来入侵危害最为严重的国家之一,在外来物种入侵的预警、管理和治理等方面形势严峻。该研究报道了中国西番莲科(Passifloraceae)西番莲属(Passiflora Linn.)一个新归化种,即桑叶西番莲(P.morifolia Mast.),并提供了形态描述和野外生态照片。桑叶西番莲原产于中美洲和南美洲的热带地区,现发现新归化于我国云南省普洱市孟连县的竜山龙血树省级自然保护区。桑叶西番莲的主要鉴别特征为叶片草质,掌状3浅裂,疏被短硬毛,托叶卵形,半抱茎,聚伞花序退化,苞片线状,具1~2花,花梗长3~6 cm,花瓣白色,副花冠基部紫色,浆果成熟时紫黑色,被短刺毛和白霜。国产种类中,桑叶西番莲与龙珠果(Passiflora foetida)最为近似,但后者全株被柔毛和腺毛,叶柄不具腺体,花序苞片一至三回羽状分裂,丝状的副花冠基部常粉红色。此外,还简要评估了桑叶西番莲的危害和入侵风险。     

Timing of reproduction in a prairie legume: seasonal impacts of insects consuming flowers and seeds

Summary Seasonal patterns of insect damage to reproductive tissue of the legume Baptisia australis were studied for three years in native tallgrass priairie. Contrasting seasonal patterns of damage were associated with the major species of insect consumers. The moth Grapholitha tristegana (Olethreutidae) and the weevil Tychius sordidus (Curculionidae), which together infested 80–100% of developing fruits (pods), consistently damaged more seeds on average in early than in late maturing pods. But while late opening flowers were less subject to attack from moths and weevils, they were more subject to attack from chewing insects, particularly blister beetles (Epicauta fabricii, Meloidae), which destroyed >80% of all flowers and developing young pods (including moth and weevil larval inhabitants). The blister beetles arrived late in the flowering season and fed particularly on young reproductive tissue, allowing larger, older pods that had developed from early opening flowers to escape destruction. The relative abundances and impacts of blister beetles, moths, and weevils varied from year to year. Adding to the uncertainty of reproductive success of the host plant were the large and variable amounts of damage to immature buds inflicted by insects (including the blister beetles and weevil adults) and late killing frosts. Thus, timing of flowering is critical to success in seed production for B. australis. The heavy impacts of insects and weather can result in a very narrow window in time (which shifts from year to year) during which B. australis can flower with any success. The opposing pressures exerted by insects and weather on floral reproductive success may act in concert with other features of the plant's biology to foster the maintenance of considerable diversity in flowering times among individuals in local populations of B. australis.     

The design of trapping devices in pollination traps of the genus Arum (Araceae) is related to insect type

Pollinators have long been known to select for floral traits, but the nature of this relationship has been little investigated in trap pollination systems. We investigated the trapping devices of 15 Arum spp. and compared them with the types of insects trapped. Most species shared a similar general design of trap chamber walls covered in downward‐pointing papillate cells, lacunose cells in the chamber wall and elongated sterile flowers partially blocking the exit of the trap. However, there was significant variation in all these morphological features between species. Furthermore, these differences related to the type of pollinator trapped. Most strikingly, species pollinated by midges had a slippery epidermal surface consisting of smaller papillae than in species pollinated by other insects. Midge‐pollinated species also had more elongated sterile flowers and tended to have a larger lacunose area. We conclude that pollination traps evolve in response to the type of insect trapped and that changes to the slippery surfaces of the chamber wall are an important and previously little recognized variable in the design of pollination traps. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172 , 385–397.     

Response of natural populations of predators and parasitoids to artificially induced volatile emissions in maize plants (Zea mays L.)

1 In response to herbivore attack, maize plants (Zea mays L.) emit a specific blend of induced volatiles. Artificial damage and subsequent treatment of the damaged site with caterpillar regurgitant induces the same response. The induced volatile chemicals are known to be highly attractive to several parasitoids of herbivores in laboratory bioassays, but very limited information is available on how the plant odours affect entomophagous insects in the field. 2 Experiments were conducted to determine if induced maize volatiles attract parasitic and predatory insects under field conditions and whether they affect their spatial distribution. 3 In a preliminary field experiment with blue sticky traps near treated (damaged and treated with caterpillar regurgitant) and healthy plants, more entomophagous insects (total number of parasitic Hymenoptera, Anthocoridae and Syrphidae) were trapped near treated plants than near healthy plants. 4 In a second experiment, attraction to the induced volatiles was monitored with sticky traps placed next to treated and healthy maize plants in a regular maize field. No significant differences between the two treatments were found, but significantly more insects (parasitic wasps, thrips and anthocorid bugs) were trapped near to the top of plants than on traps placed near the mid‐stem. Displacement of these insect groups within the field seemed to occur principally over the canopy, but under severe weather conditions they travelled lower in the canopy. 5 In a third experiment, the effect of induced maize odours on the spatial distribution of predators and parasitoids was investigated by placing sticky traps at different distances from healthy and treated plants. The higher catches of parasitoids near treated plants and the increased presence of these insects on the downwind side of treated plants support the notion that herbivore‐induced maize odours attract natural enemies of maize pests in the field.     

Do carnivorous plants use volatiles for attracting prey insects?

1.  Scientists have been fascinated by carnivorous plants for centuries and they have thoroughly investigated how these plants can benefit from insect capture for example through increased growth, earlier flowering, and increased seed production. How prey is actually lured into the traps, however, is less well understood. Trapping prey may be achieved in a random way, for example by camouflaging the traps (hiding them in the surrounding vegetation), so that prey is trapped by accidental landing on the trap leaves or wind drift, or in the other extreme, trapping may involve mimicry of other attractive resources such as fruits or flowers by using specific visual or olfactory signals to attract a specific prey assemblage.
2.  We investigated for the first time volatiles of the trapping leaves of carnivorous plant species by dynamic headspace methods. We present data on the venus flytrap Dionaea muscipula , the sundew Drosera binata , and the North American pitcher plants Sarracenia flava , Sarracenia leucophylla , Sarracenia minor , and Sarracenia purpurea . A large number of compounds and relatively high emission rates were found in three of the North American pitcher plants ( S. flava , S. leucophylla , and S. minor ) with compounds typically found in flowers or fruits. This suggests together with other features (e.g. colour, nectar production) that these traps are possibly flower or fruit mimics. The leaves of S. purpurea , Dionaea muscipula , and Drosera binata emitted much weaker scents with lower numbers of components, consisting mainly of volatiles typically emitted from green leaves.
3.  We discuss whether or not the use of volatiles for attracting prey animals is linked with specific trapping mechanisms and whether carnivorous plants can be grouped into specialized 'olfactory syndromes'.     

The fate of flowers and fruits of Cornus sanguinea L. in three contrasting Mediterranean habitats

Summary In the Mediterranean region of southern France, the fate of flowers and fruits of Cornus sanguinea, a deciduous shrub, was studied in three contrasting habitats: (1) an abandoned olive grove, (2) the edge and (3) the interior of a deciduous forest. Abundance of flowering and fruiting of C. sanguinea differed widely between the three habitats. The fate of the flowers, on the other hand, did not differ significantly between habitats. Taking all three habitats together, 77% of the flowers aborted, 23% initiated fruits, 6% developed mature fruits, and 3% produced ripe fruits that were eaten by birds. Likewise, there were for the most part no significant differences in the fate of immature and mature fruits between the habitats. On average, 58% of the immature fruits were abscised undamaged, 24% matured, 10% were damaged by insects and 8% dried up. Of the mature fruits, on average, 51% were eaten by birds, 23% damaged by insects, 20% dried up and 6% fell to the ground undamaged. Independent of habitat conditions, C. sanguinea seems to regulate the quantity of its seed crop primarily by limiting the number of flowers and secondarily by aborting surplus immature fruits, and the number of flowers is mainly controled by resource availability and genetic factors. In the case of C. sanguinea, both the fruit/flower ratio and the proportion of flowers producing mature fruits that are eaten by birds remain constant over a wide range of environmental conditions.     

Do exotic bumblebees and honeybees compete with native flower-visiting insects in Tasmania?

Honeybees, Apis mellifera, have been introduced by man throughout the globe. More recently, other bee species including various bumblebees (Bombus spp.) have been introduced to several new regions. Here we examine the impacts of honeybees and the bumblebee, Bombus terrestris, on native flower-visiting insects in Tasmania. To assess whether native insects have lower abundance or are excluded in areas that have been colonised by exotic bees, we quantified the abundance, diversity and floral preferences of flower-visiting insects at sites where bumblebees and honeybees were present, and compared them to sites where they were absent. This was achieved by hand searches at 67 sites, and by deploying sticky traps at 122 sites. Honeybees were by far the most abundant bee species overall, and dominated the bee fauna at most sites. There was considerable niche overlap between honeybees, bumblebees and native bees in terms of the flowers that they visited. Sites where bumblebees were established had similar species richness, diversity and abundance of native flower-visiting insects compared to sites where bumblebees were absent. In contrast, native bees were more than three times more abundant at the few sites where honeybees were absent, compared to those where they were present. Our results are suggestive of competition between honeybees and native bees, but exclusion experiments are needed to provide a definitive test.     

Floral structure and ontogeny in Globba (Zingiberaceae)

We present new comparative morphological and ontogenetic data on flowers and bulbils of Globba (Zingiberaceae) to clarify their homologies. Globba flowers are characteristically Zingiberaceous, possessing a single stamen and epigynous (``supragynopleural') nectaries, but are unusual as the anther bears triangular lateral outgrowths and the style is held tightly in position across the curvature of the filament like a bowstring. Floral ontogeny in Globba is similar to other Zingiberaceae. Characteristic features, such as anther wings, occur late in development, shortly before anthesis. Unusually Globba has zygomorphic style anatomy with only two abaxial vascular bundles, in contrast to most other Zingiberaceae, which possess three stylar traces. The ovary is unilocular and lacks septa. Bulbils have enclosing bracts and replace flowers in the lower part of the inflorescence; they consist of a shoot with an enlarged corky storage root forming the bulk of the propagule.     

The coconut mite, Aceria guerreronis, in Benin and Tanzania: occurrence, damage and associated acarine fauna

The coconut mite Aceria guerreronis (Eriophyidae) is considered the most important pest of coconut fruits in Africa; however, quantitative knowledge about its distribution and abundance is lacking. We conducted four diagnostic surveys—three in Southern Benin and one along the coast of Tanzania—to determine the distribution of A. guerreronis and the severity of its damage to coconut fruits, as well as the diversity and abundance of other associated mites and potential natural enemies. Aceria guerreronis was found in all visited plantations with the percentage of damaged fruits varying considerably among plantations—67–85% in Benin and 43–81% in Tanzania. Overall, 30–40% of the fruit surfaces were damaged by A. guerreronis. Damage severity increased with fruit age and negatively affected fruit weight of 7- to 12-months-old fruits. Aceria guerreronis was by far the most abundant mite on coconut fruits but its abundance depended on fruit age. The highest densities of A. guerreronis were observed on 3- to 4-months-old fruits. Neocypholaelaps sp. (Ameroseiidae) was the most abundant mite on inflorescences. Three species of predatory mites (Phytoseiidae)—Neoseiulus baraki, N. neobaraki and N. paspalivorus—were the most commonly found predatory mites beneath the coconut bracts in association with A. guerreronis. Neoseiulus neobaraki was the prevailing predator in Tanzania while N. paspalivorus was the most frequent predator in Benin. Other mites found beneath the bracts were the herbivore Steneotarsonemus furcatus (Tarsonemidae) and the detritivore and fungivore Tyrophagus putrescentiae (Acaridae).     

Phytophagous insect oviposition shifts in response to probability of flower abortion owing to the presence of basal fruits

Phytophagous insects use a wide range of indicators or associated cues to avoid laying eggs in sites where offspring survival is low. For insects that lay eggs in flowers, these unsuitable sites may be created by the host plant's resource allocation to flowers. In the sequentially flowering host plant, Yucca glauca, late‐opening distal flowers are more likely to be aborted in the presence of already‐initiated basal fruits because they are strong resource sinks. If flowers are aborted, all eggs of the phytophagous insect, Tegeticula yuccasella, within the flower die. We used the phytophagous insect T. yuccasella that lays eggs in and pollinates host plant Y. glauca flowers to test the hypothesis that phytophagous insect females are less likely to invest eggs in host plant flowers if basal fruits are present because they are more likely to be aborted. We also investigated potential predictors of arrival of T. yuccasella at inflorescences at the onset of flowering. These factors may influence a phytophagous insect's decisions to select oviposition sites. We carried out a behavioral experiment using wild‐caught T. yuccasella females on manipulated inflorescences with distal flowers with basal fruits and without fruits. As potential predictors of T. yuccasella arriving at inflorescences, we used floral display size and day of onset of flowering. In support of our hypothesis, our experimental results showed that T. yuccasella was significantly less likely to oviposit in distal flowers on inflorescences with basal fruits. We also found that T. yuccasella arrival was higher at inflorescences with larger floral display size and earlier in the flowering season. These findings uncover a novel indicator of unsuitable oviposition sites—the presence of basal fruits, that phytophagous insects use to make oviposition decisions. Further, our study contributes to the growing body of evidence that shows that females prefer sites that increase the probability of survival of their offspring.     

Mimicry and mutualism in carnivorous pitcher plants (Sarraceniaceae, Nepenthaceae, Cephalotaceae, Bromeliaceae)

The carnivorous pitcher plants of the Sarraceniaceae, Nepenthaceae and Cephalotaceae seem to have developed attraction and rewarding systems which resemble those of many flowers. Contrary to a previous view, Batcsian mimicry does not appear to apply to pitcher traps because: (a) there is no evidence of insects visiting traps by mistake, (b) no model is known for any one of the traps, (c) the duration of the trap activity and the structure of the plant community are not compatible with a deceptive mimetic status, (d) nectar which is a real reward is provided to visiting insects by the pitcher plants. It is suggested that these plants perform mutual rather than deceptive relations with the insect communities in their habitats. Insects benefit from nectar which is provided by pitchers and which serves for their nutrition in habitats where sources of floral nectar might be either uncommon or absent. At the same time the insects pay the plants in a small portion of their community which is 'sacrificed' as prey and consumed by the plants, which grow in nutrient deficient soils.