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1.
Gerald Mayr 《Pal?ontologische Zeitschrift》2007,81(4):457-462
The taxonomy and phylogenetic affinities of the putative “New World vulture”Eocathartes robustus,Lambrecht, 1935 and the “hornbill”Geiseloceros robustus
Lambrecht, 1935 from the Middle Eocene of the Geisel Valley in Germany are revised. It is shown that the holotype specimens belong
to a single individual, whose osteology closely resembles that ofStrigogyps sapea (Peters, 1987) from the Middle Eocene of Messel (Germany). The species is classified intoStrigogyps robustus (Lambrecht, 1935), n. comb., and provides further evidence for the great similarity between the Eocene avifaunas of the Geisel Valley
and Messel.Strigogyps is a representative of the Ameghinornithidae whose phylogenetic affinities are uncertain; there is no fossil record of either
Cathartidae (New World vultures) or Bucerotidae (hornbills) from the Geisel Valley. 相似文献
2.
The contribution of insectivorous birds to reducing crop damage through suppression of herbivory remains underappreciated, despite their role as cropland arthropod predators. We examined the roles of farming system, crop cover pattern, and structural configuration in influencing assemblage composition of insectivorous birds and their herbivorous arthropod prey across maize fields, and determined how bird exclusion affects crop herbivory levels. To achieve these objectives, we collected data across a sample of organic and conventional small‐scale non‐Bt maize farms in western Kenya. Assessments of abundance, diversity, and richness of insectivorous birds and abundance of their arthropod prey were compared between organic and conventional small‐scale non‐Bt maize on monocultured and inter‐cropped farms. We also employed bird exclusion experiments to assess impacts of bird predation on herbivorous arthropod abundance. Results showed that higher structural heterogeneity supported higher insectivorous bird richness, particularly under organic systems, dense trees, large woodlots, and thick hedgerows. Bird abundance further increased with crop diversity but not in relation to cropping method, hedgerow type, or percent maize cover per se. Conversely, herbivorous arthropod abundance and richness increased on conventional farms and those with higher percent maize cover, but were unaffected by cropping methods, tree, or hedgerow characteristics. Birds’ arthropod prey was more abundant under completely closed experimental plots compared with open or semi‐closed plots, confirming a significant linkage between birds and herbivorous arthropod suppression. In this study, we demonstrate importance of structural heterogeneity in agricultural landscapes, including diverse croplands and on‐farm trees to maximize insectivorous birds’ contribution to reducing crop arthropod herbivory. Abstract in Swahili is available with online material. 相似文献
3.
Han Gil Choi Ji Hee Lee Young-Kug Choo Kyu-Yun Chai Young Sik Kim Jung-Soo Han Anchana Prathep Ki Wan Nam 《Phycological Research》2006,54(4):302-307
The seasonal growth and reproductive phenology of Neorhodomela aculeata (Perestenko) Masuda and Ceramium kondoi Yendo, and the food preferences of herbivorous snails were examined to elucidate (i) why snails select the fronds of N. aculeata for their habitat; and (ii) the survival strategies of the two red algae under grazing pressures. The maximal lengths and weights of both algal species were recorded for each season over a 12‐month period beginning with the spring of 2003. C. kondoi grew in length at a faster rate than N. aculeate, whereas the turf alga N. aculeata produced new branches from the tips of broken branches. The reproductive period of C. kondoi was between the spring and summer but the reproductive organs of N. aculeata were observed throughout the year. The algal loss rate of fresh N. aculeata to snails was low but snails had a food preference for N. aculeata when compared to C. kondoi in an artificial food experiment. These results indicate that snails may adapt to chemical compounds characteristic of N. aculeata and that the alga further reduces predation damage by its structural resistance. In conclusion, the survival strategies of C. kondoi appear to be rapid growth, seasonal sexual reproduction, and a delicately branched frond morphology that reduces stable feeding patterns of its predators plus high tissue nitrogen content, whereas the survival strategy of N. aculeata includes regenerative growth responses, structural toughness and chemical defenses while under the grazing pressure of herbivorous snails. 相似文献
4.
S. Gilbert K. Norrdahl H. Tuomisto G. Söderman V. Rinne E. Huusela‐Veistola 《Journal of Applied Entomology》2015,139(7):539-552
Insects are major contributors to farmland biodiversity, and their economic roles are also diverse. Many herbivorous species are crop pests, while predatory insects have the potential to act as biological controls against pests. Overall insect diversity has declined as a result of intensified agricultural practices. Riparian buffers may support insect populations in intensively cultivated areas, but their actual impact on the balance between harmful pests and beneficial predators is not known. It can be postulated that this impact may vary depending on the characteristics and location of the riparian buffer itself. We investigated the possibility that the biotic and abiotic attributes of agricultural riparian buffers adjoining crop fields and watercourses can explain the species composition of hemipteran assemblages. In particular, we were interested in the abundances of species belonging to the genus Nabis (generalist predators) and recognized and potential pests of cereal crops. Riparian buffer width and the presence or absence of woody plants were not associated with hemipteran species turnover among riparian buffers. In contrast, differences in the degree of dominance by grasses, in plant species turnover, and in which crop plant was cultivated in the adjacent field, explained a significant proportion of the variance in hemipteran species turnover. The abundance of predatory Nabis species increased with increasing riparian buffer width, whereas the abundance of recognized and potential crop pests decreased. The reverse patterns in the predatory and herbivorous Heteroptera suggest that increasing riparian buffer width might enhance biological control by Nabis predators. 相似文献
5.
Chemosensory responses to foods by an herbivorous acrodont lizard, <Emphasis Type="Italic">Uromastyx aegyptius</Emphasis> 总被引:2,自引:0,他引:2
Actively foraging lizards use the lingual-vomeronasal system to identify prey by chemical cues, but insectivorous ambush
foragers do not. The major clade Iguania includes numerous herbivores and omnivores; among them, two iguanid and one agamine
species identify plant and animal foods by tongue flicking, and data suggest that the leiolepidine Uromastyx acanthinurus may as well. We conducted experiments on chemosensory response to food by the herbivorous U. aegyptius. When chemical stimuli were presented on cotton balls in experiment 1, the lizards exhibited greater responsiveness (tongue-flick
attack scores) to chemical stimuli from crickets and a preferred plant food (dandelion flowers) than from deionized water.
When chemical stimuli were on ceramic tiles in experiment 2, the lizards exhibited greater total tongue flicks to cricket
stimuli than to any other stimuli, and to dandelion than to deionized water. Lizards bit more frequently in response to cricket
and dandelion cues than to stimuli from a nonpreferred plant (carrot) and deionized water. Tongue-flick attack scores were
greater in response to cricket and dandelion stimuli than to carrot or water stimuli. These findings are consistent with the
hypothesis that herbivores, even those having ambush-foraging ancestors, use chemical cues to identify potential foods. The
data support the hypothesis that chemosensory responses correspond to diet. Because most lizards are generalist predators,
studies of herbivorous species can provide important information on possible evolutionary adjustment of chemosensory response
to dietary shifts.
Electronic Publication 相似文献
6.
1. Omnivorous predators can protect plants from herbivores, but may also consume plant material themselves. Omnivores and their purely herbivorous prey have previously been thought to respond similarly to host‐plant quality. However, different responses of omnivores and herbivores to their shared host plants may influence the fitness, trophic identity, and population dynamics of the omnivores. 2. The aim of the present study was to show that an omnivorous heteropteran (Anthocoris nemorum L.) and two strictly herbivorous prey species respond differently to different genotypes of their shared host plant, Salix. Some plant genotypes were sub‐optimal for the omnivore, although suitable for the herbivores, and vice versa. 3. The contrasting patterns of plant suitability for the omnivore and the herbivores highlight an interaction between plant genotype and omnivores' access to animal food. Plant genotypes that were sub‐optimal for the omnivore when herbivores were experimentally excluded became the best host plants when herbivores were present, as in the latter situation additional prey became available. By contrast, the quality of plant genotypes that were intrinsically suitable for omnivores, did not improve when herbivores were present as these plant genotypes were intrinsically sub‐optimal for herbivores, thus providing omnivores with almost no additional animal food. 4. The differential responses of omnivores and their prey to the same host‐plant genotypes should allow omnivores to colonise sub‐optimal host plants in their capacity as predators, and to colonise more suitable host plants in their capacity as herbivores. It may thus be difficult for Salix to escape herbivory entirely, as it will rarely be unsuitable for both omnivores and pure herbivores at the same time. 相似文献
7.
Plants respond differently to damage by different herbivorous insects. We speculated that sibling herbivorous species with
different host ranges might also influence plant responses differently. Such differences may be associated with the diet breadth
(specialization) of herbivores within a feeding guild, and the specialist may cause less intensive plant responses than the
generalist. The tobacco Nicotinana tabacum L. is the common host plant of a generalist Helicoverpa armigera (Hübner) and a specialist H. assulta Guenée (Lepidoptera, Noctuidae). The induced responses of tobacco to feeding of these two noctuid herbivores and mechanical
wounding were compared. The results showed that the feeding of the specialist H. assulta and the generalist H. armigera resulted in the same inducible defensive system, but response intensity of plants was different to these two species. Inductions
of jasmonic acid (JA), lipoxygenase (LOX), and proteinase inhibitors (PIs) were not significantly different concerning these
two species, but H. assulta caused the less intensive foliar polyphenol oxidase (PPO) increase, more intensive nicotine and peroxidase (POD) increases
in tobacco than H. armigera. The defensive response of plant to herbivores with different diet breadth seems to be more complicated than we expected,
and the specialist does not necessarily cause less intensive plant responses than the generalist. 相似文献
8.
FriĐgeir Grímsson Reinhard Zetter Conrad C. Labandeira Michael S. Engel Torsten Wappler 《Grana》2017,56(1):37-70
The middle Eocene Messel and Eckfeld localities are renowned for their excellently preserved faunas and diverse floras. Here we describe for the first time pollen from insect-pollinated plants found in situ on well-preserved ancient bees using light and scanning electron microscopy. There have been 140 pollen types reported from Messel and 162 pollen types from Eckfeld. Here we document 23 pollen types, six from Messel and 18 from Eckfeld (one is shared). The taxa reported here are all pollinated by insects and mostly not recovered in the previously studied dispersed fossil pollen records. Typically, a single or two pollen types are found on each fossil bee specimen, the maximum number of distinct pollen types on a single individual is five. Only five of the 23 pollen types obtained are angiosperms of unknown affinity, the remainder cover a broad taxonomic range of angiosperm trees and include members of several major clades: monocots (1 pollen type), fabids (7), malvids (4), asterids (5) and other core eudicots (1). Seven types each can be assigned to individual genera or infrafamilial clades. Since bees visit only flowers in the relative vicinity of their habitat, the recovered pollen provides a unique insight into the autochthonous palaeo-flora. The coexistence of taxa such as Decodon, Elaeocarpus, Mortoniodendron and other Tilioideae, Mastixoideae, Olax, Pouteria and Nyssa confirms current views that diverse, thermophilic forests thrived at the Messel and Eckfeld localities, probably under a warm subtropical, fully humid climate. Our study calls for increased attention to pollen found in situ on pollen-harvesting insects such as bees, which can provide new insights on insect-pollinated plants and complement even detailed palaeo-palynological knowledge obtained mostly from pollen of wind-pollinated plants in the dispersed pollen record of sediments. In the case of Elaeocarpus, Mortoniodendron, Olax and Pouteria the pollen collected by the middle Eocene bees represent the earliest unambiguous records of their respective genera. 相似文献
9.
I. Yu. Parnikoza P. Loro N. Yu. Miryuta V. A. Kunakh I. A. Kozeretska 《Cytology and Genetics》2011,45(3):170-176
Under the environmental conditions of the Point Thomas Oasis (King George Island, the South Shetland Islands), we studied
the influence of month-long artificial treatment with fresh water, salt water, and guano solution on the biometric characteristics,
chlorophyll content, as well as the nuclear area of leaf parenchymal cells and nuclear DNA content, in a maritime Antarctic
aboriginal plant Deschampsia antarctica. The modeled factors induced an increase in the generative shoot height and the length of the largest leaf but did not influence
the number of flowers. Treatment with guano caused an increase in the chlorophyll a and b contents, while fresh water treatment only led to some increase in chlorophyll a. Fluctuations of physiologically significant traits, such as the nuclear area and DNA content in the leaf parenchyma cells
of D. antarctica, have been traced under the influence of the studied factors. Understanding of the hierarchy of influence of these factors
as well as and sensitivity of plants of this species to external agents require further investigation. 相似文献
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12.
Changyou Li Xiaozhao Song Guoxun Li Ping Wang 《Insect biochemistry and molecular biology》2009,39(10):726-734
The action of plant cysteine proteases on the midgut peritrophic membrane (PM) of a polyphagous herbivorous lepidopteran, Trichoplusia ni, was studied. Proteins in PMs isolated from T. ni larvae were confirmed to be highly resistant to the serine proteinases trypsin and chymotrypsin, but were susceptible to degradation by plant cysteine proteases, which is consistent with the known molecular and biochemical characteristics of the T. ni PM proteins. However, the PM proteins were not degraded by plant cysteine proteases in larvae or in the presence of larval midgut fluid in vitro. With further biochemical analysis, cysteine protease-inhibiting activity was identified in the midgut fluid of T. ni larvae. The cysteine protease-inhibiting activity was heat resistant and active in the tested pH range from 6.0 to 10.0, but could be suppressed by thiol reducing reagents or reduced by treatment with catalase. In addition to T. ni, cysteine protease-inhibiting activity was also identified from two other polyphagous Lepidoptera species, Helicoverpa zea and Heliothis virescens. In conclusion, results from this study uncovered that herbivorous insects may counteract the attack of plant cysteine proteases on the PM by inhibiting the potentially insecticidal cysteine proteases from plants in the digestive tract. However, the biochemical identity of the cysteine protease-inhibiting activity in midgut fluid has yet to be identified. 相似文献
13.
Correlation between plant size and reproductive output may be modified by herbivory in accordance with host plant density
and the presence of nonhost plants. To elucidate the effects of nonhost plant density and host plant density on the intensity
of herbivory and reproductive output of the host plant in relation to plant size under natural conditions, we investigated
the abundance of three lepidopteran insects, Plutella maculipennis, Anthocharis scolymus, and Pieris rapae the intensity of herbivory, and fruit set of their host plant, Turritis glabra (Cruciferae). To elucidate the effects of nonhost and host plant density, we selected four categories of plots under natural
conditions: low density of nonhost and high density of host plants; low density of both nonhost and host plants; high density
of both nonhost and host plants; and high density of nonhost and low density of host plants. The plant size indicated by stem
diameter was a good predictor of the abundance of all herbivorous species. The effects of density of nonhost and host plants
on the abundance of insects varied among species and stages of insects. As the abundance of insects affected the intensity
of herbivory, herbivory was more apparent on larger host plants in plots with low density of both nonhost and host plants.
Consequently, the correlation between plant size and the number of fruits disappeared in low plots with density of both nonhost
and host plants. In this T. glabra– herbivorous insect system, the density of nonhost plants and host plants plays an important role in modifying the relationship
between plants and herbivores under natural conditions.
Received: July 19, 1999 / Accepted: June 15, 2000 相似文献
14.
Jay K. Goldberg Genevieve Pintel Stacey L. Weiss Emília P. Martins 《Ecology and evolution》2019,9(8):4733-4738
Many lizards are olfactory foragers and prey upon herbivorous arthropods, yet their responses to common herbivore‐associated plant volatiles remain unknown. As such, their role in mediating plant indirect defenses also remains largely obscured. In this paper, we use a cotton‐swab odor presentation assay to ask whether lizards respond to two arthropod‐associated plant‐derived volatile compounds: 2‐(E)‐hexenal and hexanoic acid. We studied the response of two lizard species, Sceloporus virgatusand Aspidoscelis exsanguis, because they differ substantially in their foraging behavior. We found that the actively foraging A. exsanguisresponded strongly to hexanoic acid, whereas the ambush foraging S. virgatus responded to 2‐(E)‐hexenal—an herbivore‐associated plant volatile involved in indirect defense against herbivores. These findings indicate that S. virgatus may contribute to plant indirect defense and that a species' response to specific odorants is linked with foraging mode. Future studies can elucidate how lizards use various compounds to locate prey and how these responses impact plant‐herbivore interactions. 相似文献
15.
Sabine Karg 《Vegetation History and Archaeobotany》1995,4(1):41-50
Weed assemblages from late medieval cornfields have been studied for the first time in northern Switzerland. Eleven samples from at least two different grain stores were investigated. The samples were collected from the carbonised remains of six wooden houses built in the late 13th century A.D. and which burnt down in the middle of the 15th century. The weed floras found in the spelt (Triticum spelta) and oats (Avena sativa) indicate a high botanical diversity in the cornfields at harvest time. Although oats are normally a summer crop and spelt a winter crop, both summer and winter crop weeds (as well as many different present-day grassland taxa) were found in each type of grain. Most of the weeds found were perennial plants, which was interpreted as an indication of both extensive tillage of the arable land and application of the three-field rotation system (Dreifelderwirtschaft). The spectra of the two palaeophytocoenoses (assemblages of ancient plant remains) studied suggest that the phytosociological method may not be reliable for classification of the late medieval remains into summer and winter crop weed communities. These findings should provide a better understanding of the development of anthropogenic plant communities, and in particular, the development of crop weed communities. 相似文献
16.
ANA PINEDA ROXINA SOLER BERHANE T. WELDEGERGIS MPOKI M. SHIMWELA JOOP J. A. VAN LOON MARCEL DICKE 《Plant, cell & environment》2013,36(2):393-404
Beneficial soil‐borne microbes, such as mycorrhizal fungi or rhizobacteria, can affect the interactions of plants with aboveground insects at several trophic levels. While the mechanisms of interactions with herbivorous insects, that is, the second trophic level, are starting to be understood, it remains unknown how plants mediate the interactions between soil microbes and carnivorous insects, that is, the third trophic level. Using Arabidopsis thaliana Col‐0 and the aphid Myzus persicae, we evaluate here the underlying mechanisms involved in the plant‐mediated interaction between the non‐pathogenic rhizobacterium Pseudomonas fluorescens and the parasitoid Diaeretiella rapae, by combining ecological, chemical and molecular approaches. Rhizobacterial colonization modifies the composition of the blend of herbivore‐induced plant volatiles. The volatile blend from rhizobacteria‐treated aphid‐infested plants is less attractive to an aphid parasitoid, in terms of both olfactory preference behaviour and oviposition, than the volatile blend from aphid‐infested plants without rhizobacteria. Importantly, the effect of rhizobacteria on both the emission of herbivore‐induced volatiles and parasitoid response to aphid‐infested plants is lost in an Arabidopsis mutant (aos/dde2‐2) that is impaired in jasmonic acid production. By modifying the blend of herbivore‐induced plant volatiles that depend on the jasmonic acid‐signalling pathway, root‐colonizing microbes interfere with the attraction of parasitoids of leaf herbivores. 相似文献
17.
New trogons from the early Tertiary of Germany 总被引:3,自引:0,他引:3
GERALD MAYR 《Ibis》2005,147(3):512-518
A new trogon (Aves, Trogoniformes), Primotrogon? pumilio sp. nov., is described from the Middle Eocene (49 Ma) of Messel in Germany. It is the first articulated skeleton of an Eocene trogon, of which only very few fragmentary remains were hitherto known. It is also the earliest complete skeleton of a trogon, exceeding previous finds (Primotrogon wintersteini Mayr 1999) by at least 15 million years. An isolated wing of a trogon is further identified from the early Oligocene (about 30–34 Ma) of the fossil site Frauenweiler in Germany. Primotrogon? pumilio and all other sufficiently well‐preserved early Tertiary trogons appear to be stem group representatives of the Trogoniformes, corresponding with molecular clock data indicating a mid‐Tertiary origin of crown group Trogoniformes. 相似文献
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19.
Thomas Vanhercke Srinivas Belide Matthew C. Taylor Anna El Tahchy Shoko Okada Vivien Rolland Qing Liu Madeline Mitchell Pushkar Shrestha Ingrid Venables Lina Ma Cheryl Blundell Anu Mathew Lisa Ziolkowski Nathalie Niesner Dawar Hussain Bei Dong Guoquan Liu Ian D. Godwin Jiwon Lee Melanie Rug Xue‐Rong Zhou Surinder P. Singh James R. Petrie 《Plant biotechnology journal》2019,17(1):220-232
20.
Micropopulation differences in phenol content between intertidal and subtidal individuals of the kelp Lessonia nigrescens were found. Subtidal plants showed: (1) significantly higher phenol content than intertidal individuals, in vegetative and reproductive tissues, (2) intra-plant differences, with higher content in apical frond tissues, (3) higher resistance to consumption by herbivorous fishes. The microscopic progeny of subtidal plants showed the same trend as adult plants: (1) haploid spores from subtidal plants had higher phenol content than spores from intertidal individuals, and (2) the microscopic sporophytes derived from subtidal spores and gametophytes were less consumed by herbivorous snails (Tegula tridentata) than those derived from intertidal plant propagules. No increase in phenol content was detected after mechanical injury to experimental fronds, or after transplantation to the subtidal environment.In addition to the absence of inducible responses, the different phenol content between intertidal and subtidal individuals, in adult diploid plants and also in the haploid progeny, suggests that both environments differ someway enough to fix the mentioned features on the plants of Lessonia nigrescens. It is likely that the differences in herbivory between the two distributional extremes contributed to the observed pattern. 相似文献