New faunal and biological observations on ticks in Abruzzo]

Ticks collected during the years 1975-76 in Abruzzo (Prov. l'Aquila and Chieti) Italy are reported. The following species have been identified: Ixodes canisuga, Ixodes frontalis, Ixodes hexagonus, Ixodes ricinus, Dermacentor marginatus, Haemaphysalis sulcata, Rhipicephalus bursa, Rhipicephalus sanguineus, Hyalomma marginatum. New hosts are: Felis catus for Ixodes canisuga; Scolopax rusticola, Motacilla flava, Corvus cornix for Ixodes frontalis; Sciurus vulgaris for Haemaphysalis punctata; Garrulus glandarius for Haemaphysalis sulcata. For Italy the following records are new: hosts: Corvus frugilegus for Ixodes frontalis; Coturnix coturnix and Alauda arvensis for Haemaphysalis sulcata; immature stages: Ixodes canisuga on Vulpes vulpes; Ixodes frontalis on Turdus merula; Haemaphysalis punctata on Coturnix coturnix, Phasianus colchicus, Erinaceus europaeus, Lepus europaeus; Accordingly numerous species, hosts and seasonal records are new for Abruzzo.     

Hyperostosis frontalis interna: archaeological evidence of possible microevolution of human sex steroids?

Hyperostosis frontalis interna is a restricted bilateral thickening of the frontal endocranial surface, which is frequently found in postmenopausal females today. Surprisingly, this condition had a higher male prevalence in its rare archaeological records. This is again highlighted by the oldest known male European hyperostosis frontalis interna case in an adult Celtic from 100 BC presented here. This unique specimen supports earlier suggestions of the possible microevolution of human endocrine regulation, e.g. by sex steroids, and its pathoanatomical impact.     

The genetic similarity of different generations of Neocallimastix frontalis SK

The genetic similarity of different generations of Neocallimastix frontalis SK was examined by random amplified polymorphic DNA (RAPD) profiling and internal transcribed spacer 1 (ITS1) sequence analysis. N. frontalis SK was subcultured every 2-4 days, and SK-1, SK-3M, and SK-1Y represented N. frontalis SK cultures after one subculture, 50 subcultures, and 150 subcultures. The DNA polymorphisms of the different N. frontalis SK generations were compared by RAPD profiling. The RAPD results gave the same patterns for SK-1, SK-3M and SK-1Y using 12 selected random primers. The partial 18S rDNA, 5.8S rDNA, and ITS1 regions of different generations of N. frontalis SK were amplified and sequenced. The results of alignment and pairwise similarity indicated that the analyzed rRNA sequences of SK-1, SK-3M and SK-1Y were totally identical. This study thus demonstrated genetically identical DNA polymorphisms by RAPD profiling and an unvaried ITS1 region for N. frontalis SK when the strain is subcultured frequently. This suggests that this strain is homokaryotic and grows via an asexual life cycle in vitro.     

Observations of Strange-tailed Tyrants (Alectrurus risora) and other grassland birds following army ants and armadillos

ABSTRACT.   Birds in Neotropical forests frequently follow army ants to forage for insects. Here we report the first record of several species of Neotropical grassland birds following army ants ( Labidus praedator ) and yellow armadillos ( Euphractus sexcinctus ). We observed Strange-tailed Tyrants ( Alectrurus risora ) following army ants in El Bagual Ecological Reserve in Argentina. Other species also observed following army ants included Pampas Finches ( Embernagra platensis ), Wedge-tailed Grass-finches ( Emberizoides herbicola ), Long-tailed Reed-finches ( Donacospiza albifrons ), Great Kiskadees ( Pitangus sulphuratus ), Rufous Horneros ( Furnarius rufus ), Gray Monjitas ( Xolmis cinerea ), and Pale-breasted Spinetails ( Synallaxis albescens ). Strange-tailed Tyrants and Wedge-tailed Grass-finches were also observed following armadillos. Because birds were observed capturing insects flushed by the army ants and armadillos, our observations indicate that birds that opportunistically follow army ants and armadillos benefit from the association.     

Electrophysiological and behavioral responses of Dendroctonus frontalis (Coleoptera: Curculionidae) to volatiles isolated from conspecifics

Olfactory sensitivity of the southern pine beetle, Dendroctonus frontalis Zimmermann, to compounds isolated from the mid/hindguts of newly emerged conspecific adults was assayed with coupled gas chromatography-electroantennographic detection. All previously reported pheromones for D. frontalis plus eight additional compounds (fenchyl alcohol, myrtenal, cis-verbenol, trans-pinocarveol, acetophenone, trans-myrtanol, cis-myrtanol, and 2-phenylethanol) consistently elicited antennal responses from at least one sex. The eight additional compounds were assayed individually at three release rates (0.4-0.8, 3-9, and 25-100 mg/d) for the ability to alter D. frontalis responses to traps baited with D. frontalis attractant (4 mg/d frontalin and 17 mg/d alpha-pinene). At the high release rate, cis-verbenol enhanced attraction of D. frontalis females, whereas the other seven compounds significantly reduced attraction of one or both sexes. Acetophenone significantly reduced attraction of male D. frontalis at the low release rate, and five compounds (fenchyl alcohol, trans-pinocarveol, acetophenone, cis-myrtanol, and 2-phenylethanol) reduced attraction of one or both sexes at the intermediate rate. Only acetophenone significantly altered the sex ratio of beetles trapped, decreasing the proportion of males. Attraction of predatory checkered beetles (Cleridae) was enhanced by cis-verbenol released at the high rate but was not altered by any compound inhibitory to D. frontalis. Analyses of volatiles from individual D. frontalis indicated that the majority of the eight compounds were produced in greater quantities by newly emerged beetles than ones attacking pine bolts. Five of the compounds were associated predominantly with one sex. Possible ecological roles of these compounds in the biology of D. frontalis are discussed.     

Transcranial magnetic stimulation in research of emotion in the healthy and patients with epilepsy

The main aim of this work was by using transcranial magnetic stimulation to investigate mechanisms of interhemispheric organization the emotion in the healthy and patients with epilepsy. The research was carried out on three groups: the first and second groups of healthy and third group of the patients with idiopatical epilepsy. The first and third groups received transcranial magnetic stimulation on right and left frontalis area. The second group was control (sham transcranial magnetic stimulation). Is shown, that transcranial magnetic stimulation of right frontalis area increases the examining time on negative photos and decreases on positive photos. Transcranial magnetic stimulation of left frontalis area in the healthy and patients with epilepsy increases the examining time on positive photos and decreases on negative photos. The right hemisphere at the healthy and patients with epilepsy in the greater degree is connected to negative marks of emotions, and left hemisphere with positive marks of emotions.     

A mitochondrial-like targeting signal on the hydrogenosomal malic enzyme from the anaerobic fungus Neocallimastix frontalis: support for the hypothesis that hydrogenosomes are modified mitochondria

The hydrogenosomal malic enzyme (ME) was purified from the anaerobic fungus Neocallimastix frontalis . Using reverse genetics, the corresponding cDNA was isolated and characterized. The deduced amino acid sequence of the ME showed high similarity to ME from metazoa, plants and protists. Putative functional domains for malate and NAD⁺/NADP⁺ binding were identified. Phylogenetic analysis of the deduced amino acid sequence of the new ME suggests that it is homologous to reference bacterial and eukaryotic ME. Most interestingly, the cDNA codes for a protein which contains a 27-amino-acid N-terminus which is not present on the purified mature protein. This presequence shares features with known mitochondrial targeting signals, including an enrichment in Ala, Leu, Ser, and Arg, and the presence of an Arg at position –2 relative to amino acid 1 of the mature protein. This is the first report of a mitochondrial-like targeting signal on a hydrogenosomal enzyme from an anaerobic fungus and provides support for the hypothesis that hydrogenosomes in Neocallimastix frontalis might be modified mitochondria.     

Der KuckuckTapera naevia und seine Wirte in Surinam

Zusammenfassung Unter 12 mit Eiern belegten Nestern vonCerthiaxis cinnamomea in Surinam wurden 8 vonTapera naevia belegt. Von 13 Eiern vonTapera waren 6 weiß, 6 blau-grün und eins bläulich-weiß. In einem Nest vonSynallaxis gujanensis wurde während der Eiablage des Wirtes ein weißes Ei vonTapera gelegt. Ein zweites blau-grünesTapera-Ei wurde hinzugelegt, als die Eier 4–10 Tage bebrütet waren. Aus dem erstenTapera-Ei schlüpfte nach 15 Tagen Bebrütung der Jungvogel. DieSynallaxis-Jungen schlüpften nach 18 Tagen. Der Jungvogel vonTapera ist beim Schlüpfen nackt und rosa gefärbt. Seine Haut verfärbt sich nach 2 Tagen in Violett. Die Jungen des Wirts verschwanden einen Tag nach dem Schlüpfen, der junge Kuckuck war an diesem Tag doppelt so groß wie sie. Er wurde von beiden Pflegeeltern gefüttert und wuchs schnell heran. Am 6. Lebenstag zeigten sich die ersten Blutkiele, aus denen am 9. Lebenstag die ersten Federspitzen hervorbrachen. Am 18. Lebenstag verließ der junge Kuckuck das Nest, bevor er voll flugfähig war.

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Summary Additional records on the parasitic Cuckoo,Tapera naevia and its hosts in Surinam as a continuation of a previous article (Haverschmidt 1955).Of 12 nests ofCerthiaxis cinnamomea 8 were parasityzed byTapera. Of 13 eggs ofTapera 6 were bluish green, 6 white and 1 bluish white.A couple ofSynallaxis gujanensis started nestbuilding in the author's garden on November 23, 1960. The first egg was laid on December 15 (nestbuilding 23 days). This egg disappeared on December 16, another egg was laid on December 17, and on December 18 the nest contained 3 white eggs: 2 ofSynallaxis and 1 ofTapera. At the next inspection on December 31 the nest contained 4 eggs: 3 white eggs (2 ofSynallaxis and 1 ofTapera) and a bluish green egg ofTapera. The whiteTapera-egg hatched on January 2 (incubation period 15 days). The nestling cuckoo was naked and of a pinkish colour, its gape was orange yellow. On January 5 the 2 eggs ofSynallaxis hatched (incubation period 18 days). Apart from a few downs on the crown they were naked, of a pinkish colour and their gape was yellowish orange. On this date the nestling cuckoo had a violet colour and was twice as big as the nestlingsSynallaxis. The bluish greenTapera-egg had disappeared. On January 6 the 2 nestlings ofSynallaxis had disappeared. They were not present on the open sandpath under the shrub containing the nest where the author must have found them in case they were thrown out of the nest by the nestling cuckoo. The author is of opinion that the nestlingSynallaxis died because they got no food as the much bigger young Cuckoo got all and that they were removed after their death by their parents. The nestling Cuckoo grew very rapidly; at the age of 10 days it had sprouting feathers and it was feathered at the age of 14 days. It uttered a chirruping sound constantly. It left the nest at the age of 18 days though it was not yet able to fly well.

     

委内瑞拉东南加勒比海岸七种海洋鲸类的潜在地理分布

本研究阐述了委内瑞拉沿海最常见的海洋鲸类的潜在地理分布情况。通过GIS分析,鲸类分布与地形和深度是相反的,以此可以获得鲸类潜在的分布图。已报告确认了16个物种(有402个目击报告),其中小布氏鲸(Balaenoptera edeni)、座头鲸(Megaptera novaeangliae)、海豚(Delphinus spp.)、圭亚那侏型豚(Sotalia guianensis)、花斑原海豚(Stenella frontalis)、长吻原海豚(Stenella longirostris)和宽吻海海豚(Tursiops truncatus)是最常见的。小布氏鲸和宽吻海海豚有可能分布于整个海岸,包括江河区域。座头鲸则可能季节性地集中分布在大陆架上的海岛沿岸和浅水区域。海豚(Delphinus spp.)有可能分布于高边坡区或沿海上升流区。花斑原海豚可能分布在东北区的西部,中部沿海以及与委内瑞拉海岸平行的岛屿周围。长吻原海豚则分布于浅海和远海区域。在一些高产的生态系统内新的物种可能正在形成,而这些潜在可能的分布图可以作为在高产生态系统内确立关键栖息地的标准,由此我们可以在委内瑞拉水域为鲸类建立新的保护区。     

基于CLIMEX和GIS的南松大小蠹在中国的适生性分析

南松大小蠹Dendroctonus frontalis Zimmermann是美洲地区危害松杉类针叶树种的蛀干害虫.本文采用CLIMEX模型与ArcGIS分析相结合的预测方法,通过确定南松大小蠹的CLIMEX气候适应性参数,分析了南松大小蠹在我国的适生范围,并利用南松大小蠹的最低致死温度对适生范围进行限制.结果表明南松...     

Finger pulse amplitude and frontalis EMG biofeedback effects of single- and two-system training.

The relationship between finger pulse amplitude (PA) and frontalis EMG was studied first by looking at general physiological changes accompanying successful bidirectional PA control. Seven successful subjects were then asked to produce two patterns of PA and EMG (PAincEMGdec and PAdecEMGdec) while receiving both PA and frontalis EMG biofeedback. Results indicate subjects can easily produce the differentiation pattern of PAdecEMGdec but cannot produce the integration pattern of PAincEMGdec. These rather paradoxical results may indicate subjects were using an "attentional" rather than "arousal" strategy for controlling PA and have implications for the use of peripheral vasomotor training as a general relaxation technique.     

Early scalp responses evoked by stimulation of the supraorbital nerve in man

In 25 healthy volunteers the supraorbital nerve was stimulated and evoked potentials were recorded. Leads were placed on the scalp and along the ipsilateral eyebrow-mastoid line and were either referred to a non-cephalic reference (on the neck, or Cv7) or linked to form bipolar derivations. As template wave form was chosen the one obtained from derivation Cz-Cv7, which had an initial triphasic component with negative (SW1a), positive (SW1b), negative (SW1c) polarity (mean latencies 0.63, 0.95 and 1.43 msec), followed by 2 negative waves (SW2 and SW3, mean latencies of 2.20 and 2.89 msec). A final positive wave could be observed in most cases (SP4, mean latency of 4.08 msec). The records collected from the various derivations showed that each component (SW1, SW2, SW3 and SP4) had a different behaviour, thus suggesting separate origins. SW1 would originate from a volley travelling from the point of stimulation towards the mastoid, probably across the ophthalmic branch of the trigeminal nerve. The subsequent components would be generated by deeply situated structures: double pulse stimulation suggests that SW1, SW2 and SW3 are generated before the first synapse, whereas SP4 is a postsynaptic event. A strong similarity exists between the components evoked by stimulation of the supraorbital and the infraorbital nerves. Local anaesthetic block of the frontal nerve on the stimulated side and monitoring of the EMG activity of m. orbicularis oculi and m. frontalis ruled out any muscle contamination of the responses described in this paper.     

Distribution of cetaceans in the offshore Gulf of Mexico

In order to comprehend better the distribution of Gulf of Mexico cetaceans, all available records of whales and dolphins in the offshore Gulf were assembled and analysed. This included sightings, strandings and captures of all species, except the Bottlenose Dolphin Tursiops truncatus , from all sources, except the recently completed GulfCet project. An attempt was made to confirm species identification for each of the records. A total of 1223 records was available for analysis. Twentyseven species of cetaceans have been confirmed to occur in the offshore Gulf of Mexico. All of the baleen whales, with the possible exception of the Bryde's Whale Balaenoptera edeni appear to be extralimital in the Gulf. The Sperm Whale Physeter macrocephalus is, by far, the most common great whale in this body of water. All previous records of Common Dolphins Delphinus spp. in the Gulf are rejected as either incorrect or unreliable, and there is currently no convincing evidence that dolphins of the genus Delphinus occur in the Gulf. The Atlantic Spotted Dolphin Stenella frontalis is the only species, other than the Bottlenose Dolphin, that regularly occurs over the continental shelf. The Pantropical Spotted Dolphin Stenella attenuata is the most common species of small cetacean in oceanic waters of the Gulf, but many other species also occur there in significant numbers.     

Geographic variation in the carotenoid plumage pigmentation of male house finches (Carpodacus mexicanus)

Geographic variation in both the colour and pattern of carotenoid plumage pigmentation displayed by males in two subspecies of house finches ( Carpodacus mexicanus frontalis and C. m. griscom ) was quantified. The extent of ventral carotenoid pigmentation (patch size) differed markedly between these two subspecies; frontalis males from the U.S. (New York, Michigan, California and Hawaii) displayed a medium patch extending from their throats to their lower bellies, while griscomi males sampled in Guerrero, Mexico displayed small patches restricted to their throats. Frontalis males sampled in Michigan and New York and griscomi males were relatively bright in colouration, while frontalis males sampled in Hawaii were relatively drab. Populations of frontalis in California showed substantial local variation in average male colouration: in two areas only 12 km apart males were as colourful and as drab as any population sampled. In aviary experiments in which they were fed either a plain seed diet or a diet supplemented with red carotenoid pigments during moult, males from all populations converged on a similar appearance, except that griscomi males attained a brighter plumage than frontalis males when their diet was supplemented with red pigments. Regardless of diet, the difference in patch size between frontalis and griscomi males persisted after moult in captivity. The author concludes that the difference in patch size between frontalis and griscomi males reflects genetic differences between these populations, but that the differences in the mean plumage colouration of males among populations reflect differences in the access that males have to carotenoid pigments during moult.     

Semiochemical emission from individual galleries of the southern pine beetle, (Coleoptera: Curculionidae: Scolytinae), attacking standing trees

We collected, identified, and quantified volatiles arising from individual gallery entrances of the monogamous bark beetle Dendroctonus frontalis Zimmermann. Samples were collected while the insects were mass attacking mature loblolly pines (Pinus taeda L.) in an established infestation in western Mississippi, 1 August through 3 October 2005. Following volatile sample collection, the entrances were dissected and categorized according to those that 1) contained a solitary female (the gallery initiating sex), 2) contained a pair that had not yet produced an egg gallery, 3) led to an egg gallery with niches and/or eggs, or 4) represented failed attacks (either abandoned or containing dead beetles). The greatest mean release rate of the female-produced aggregation pheromone components frontalin (74 ng/h) and trans-verbenol (0.35 microg/h) was detected from entrances of solitary females, whereas the highest mean quantities of the male-produced multifunctional pheromone components endo-brevicomin (18 ng/h) and verbenone (0.15 microg/h) were detected from entrances of preoviposition beetle pairs. Alpha-pinene, a host-produced monoterpene that functions as a synergist for the aggregation attractant for D. frontalis, was detected from entrances of solitary females and preoviposition pairs at a rate of 0.6 mg/h, or 3-4 orders of magnitude greater than the insect-produced components of the attractant. Our results indicate that the release rates of pheromone components used in published field studies of the chemical ecology of D. frontalis (generally > 0.1 mg/h) represent thousands of 'attack equivalents' or production rates on the scale of a beetle mass attack on a single host. Additionally, our data suggest that the loss in attractiveness of host tissue fully colonized by D. frontalis is because of the disappearance of attractants rather than an increase in inhibitors.     

Attraction of the southern pine beetle, Dendroctonus frontalis, to pheromone components of the western pine beetle, Dendroctonus brevicomis (Coleoptera: Curculionidae: Scolytinae), in an allopatric zone

Subtle differences in pheromone components of sympatric species should be attractive only to the producing species and unattractive or repellent to the nonproducing species, and thereby maintain reproductive isolation and reduce competition between species. Bark beetles Dendroctonus brevicomis and D. frontalis (Coleoptera: Curculionidae) are known to have common pheromone components, except for exo-brevicomin, which is produced by D. brevicomis. We predicted that D. frontalis would not respond to exo-brevicomin outside of the zone of sympatry with D. brevicomis. We conducted a field experiment to determine the effect of exo-brevicomin on attraction of D. frontalis and associated species in Mississippi. We determined whether D. frontalis pheromone production differed inside and outside the sympatric zone and compared the pheromone profiles with D. brevicomis within the sympatric zone. Trapping studies revealed that D. frontalis can perceive and respond positively to exo-brevicomin, an aggregation pheromone of a sympatric congener (D. brevicomis), at locations hundreds of kilometers outside the sympatric zone. Qualitative pheromone profiles showed that both species emit similar pheromone components: frontalin, endo-brevicomin, exo-brevicomin, trans-verbenol, verbenone, and myrtenol. Although not previously reported, D. frontalis males from Arizona produced exo-brevicomin. The predator Thanasimus dubius did not discriminate traps baited with exo-brevicomin and was most attracted to traps with frontalin. Hylastes beetles were significantly attracted to traps baited with exo-brevicomin in combination with other compounds. Our results raise new practical and evolutionary questions on the role of exo-brevicomin in the behavioral ecology of D. frontalis. The addition of exo-brevicomin to the current lure might increase the efficiency of trapping programs in the southeastern United States.     

Amblyomma aureolatum and Ixodes auritulus (Acari: Ixodidae) on birds in southern Brazil, with notes on their ecology

Between January 1999 and December 2000, 876 bird specimens were captured in three different ecological environments from the Reinhard Maack Park, Curitiba, State of Paraná, southern Brazil. A total of 142 birds (16.2%) were infested with Amblyomma aureolatum (Pallas 1772) (N=699) and/or Ixodes auritulus Neumann, 1904 (N=18) ticks. Questing A. aureolatum nymphs (N=2) and adults (N=5) were also collected from the soil and the vegetation. None of the I. auritulus were collected off-host. We collected only immatures of A. aureolatum on birds, but all life stages of I. auritulus. The latter species was collected on Turdus rufiventris and on Synallaxis ruficapilla, which is herein recognized as a host of I. auritulus for the first time. Moreover, this is also the first report of A. aureolatum infesting birds, and 16 different bird species were found infested. It was observed that larval infestation was positively correlated with the dry and cold season, while nymphal infestation was positively correlated with the warm and rainy season. Although only 2-years worth of data is provided, our results suggest the infestation of birds by ticks was significantly higher at the biotopes formed by forest at its first stage of regeneration 'capoeira' and the original Araucaria forest habitat 'mata' than the ecotone between forest and urban areas 'peripheral area'.     

Relaxation and subjective estimates of muscle tension: Implications for a central efferent theory of muscle control

The relationship of “awareness of muscle tension” to depth of relaxation was explored. In one experiment, accuracy of forearm flexor control was assessed using the psychophysical method of magnitude production, and depth of flexor relaxation was measured using the integrated EMG before and after EMG biofeedback training. No consistent relationship between motor-control accuracy and depth of relaxation was found. A second, similar experiment with frontalis showed increased accuracy of frontalis control with deeper relaxation. Accuracy of passive, verbal judgments of spontaneous frontalis tension fluctuation exhibited no clear relationship with depth of relaxation. It was concluded that forearm flexor and frontalis may be under the control of distinct mechanisms, and that afferent information probably contributes to the control of neither muscle. Three structural theories of the control mechanisms were considered, and one depending on the central monitoring of efferent outflow(rather than afferent inflow) seemed most compatible with the frontalis data. Both flexor and frontalis data could be accounted for by a two-phase scheme combining central outflow monitoring with the monitoring of mental contents for arousal value at very low muscle tension levels.     

Diversity and seasonal patterns of ticks parasitizing wild birds in western Portugal

The diversity and abundance of questing ticks and ticks parasitizing birds was assessed during 1?year in two recreational forests in western Portugal, a suburban forest and an enclosed game area. The aim of this study was to assess the distribution and seasonality of tick species and to understand the role of bird species as hosts for ticks. Ixodes ricinus was the most abundant questing tick collected in the enclosed game area, whereas in the suburban forest, only three ticks were collected by blanket dragging. Tick species parasitizing birds included I. ricinus, I. frontalis, I. arboricola, I. acuminatus, Haemaphysalis punctata, Hyalomma marginatum and H. lusitanicum. This is the first record of I. arboricola in Portugal. Tick prevalence and intensity of infestation differed between study areas and was higher in birds from the game area where a large population of deer and wild boar may support tick populations. Ground and shrub dwelling bird species such as Turdus merula, Erithacus rubecula and Sylvia melanocephala were the most heavily parasitized by ticks, but the importance of different bird species as hosts of larvae and nymphs of I. ricinus and I. frontalis differed. Therefore, different bird species may contribute differently for tick population maintenance.     

The effect of the presence of glucose on the fermentation of mannose by the anaerobic fungus Neocallimastix frontalis strain RE1

Abstract The disappearance of mannose and the formation of formate, acetate, lactate, ethanol and succinate by Neocallimastix frontalis strain RE1 occurred slowly when mannose was the only substrate present. When an equal quantity of glucose was present, the fermentation of mannose increased. Incubations with ¹³C-labelled mannose and glucose confirmed that the presence of both substrates resulted in increased product formation from mannose and reduced product formation from glucose. The relative proportions of products formed from the two substrates varied, possibly in part due to differences in the rates of growth of the fungus. The strains of N. frontalis able to utilize mannose may have a competitive advantage in the rumen ecosystem.