The first case of morphological differentiation of Altai Osman <Emphasis Type="Italic">Oreoleuciscus potanini</Emphasis> (Cyprinidae,Actinopterigii) in a river

The variability of osteological characters has been investigated in cyprinid fish of the genus Oreoleuciscus (Potanin Altai osman) from the river Zavkhan; this fish species is endemic for water bodies of Central Asia. Multivariate analysis of 13 quantitative parameters of the size of the cerebral and visceral skull and the pectoral girdle and the construction of ontogenetic channels allowed the detection of morphologically distinct forms in the fluvial habitats. The result obtained provides additional proof of the possibility of sympatric diversification of fish in river ecosystems. One of the two fluvial forms discovered has been shown to be identical (with regard to the osteological characters) to a previously described herbivorous form of O. potanini from the standing water bodies of the Great Lakes Hollow (Western Mongolia).     

The land/inland-water ecotones and fish population of Lake Valley (West Mongolia)

New data on fish populations of a closed desert watershed of Mongolia were obtained in 1990 and 1991. For this region periodic droughts, with the accompanying disappearance of lakes and some parts of rivers, are typical. Two forms of a Cyprinid species Oreoleuciscus humilis (dwarf Altai osman) occur in this region during wet periods which usually last for 10-30 years. The dwarf form, is characterized by a maximum SL of 200 mm and early maturation (SL = 70 mm, four years of age). It inhabits small desert rivers in dry periods which last for 3–5 years and both rivers and the riparian zone of lakes during wet periods. The larger lake form occurs only in lakes during the wet periods. It can attain a maximum size of 450 mm and matures in six years, SL = 200 mm. These two forms of O. humilis differ in feeding habits, rates of growth, and morphology. The dwarf form feeds mainly on insect larvae and on plants. The lake form consumes the same food items until it reaches 180 mm SL and then becomes piscivorous. Populations of O. humilis in lakes are restored after a dry period, originating anew from river populations of the dwarf form.Currently there is a transition from a dry period to a wet one. Orog-Nur (one of the lakes of Lake Valley) has been filling with water since 1990. In July 1991 the depth of this lake reached 0.5–1.0 m and fish were found in the lake. The large individuals of dwarf form which came to the lake from the Tuyn-Gol River became cannibals, and their growth rate increased rapidly. The homogeneous environment and low food supply in the restored lakes are suggested to be the main causes of these phenomena.     

New Specimens of Yanornis Indicate a Piscivorous Diet and Modern Alimentary Canal

A crop adapted for an herbivorous diet of seeds has previously been documented in the Early Cretaceous birds Sapeornis and Hongshanornis. Here we report on several specimens of Yanornis that preserve a crop containing fish. One specimen preserves two whole fish in the oesophagus, indicating that Early Cretaceous birds shared trophic specializations with Neornithes for the increased energetic demands of flight – namely the storing of food for later consumption when the stomach is full. Whole fish also indicate that despite their presence, teeth were not used to orally process food, suggesting the hypertrophied dentition in this taxon were utilized in prey capture. The presence of macerated fish bones in the crop of other specimens indicates the highly efficient advanced muscular system of peristalsis responsible for moving ingested items between different segments of the alimentary canal was also in place. Despite the fact many features of the modern avian alimentary canal are inferred to compensate for the absence of teeth in birds (expandable oesophagus, grinding gizzard), the derived alimentary canal was apparently present in toothed Cretaceous birds. Although Yanornis was considered to have switched their diet from piscivorous to herbivorous, based on position and morphology we reinterpret the gastroliths reported in one specimen as sand impacted in the intestines, and reconstruct the taxon as primarily piscivorous. This is a novel interpretation for fossilized gastroliths, and the first documentation of this condition in the fossil record.     

Taxonomical and palaeoecological investigations of the chondrichthyan and osteichthyan fish remains from the Middle-Late Triassic deposits of the Villány Hills (Southern Hungary)

Two sites in the Villány Hills, Hungary, have yielded rich fish assemblages from Middle to Late Triassic shallow marine deposits. The collected material comes from the Ladinian Templomhegy Dolomite Member and from the Carnian Mészhegy Sandstone Formation. The ichthyofauna is composed of both chondrichthyans (Hybodontidae indet., Palaeobates angustissimus, ‘Polyacrodus’ sp., ?Lissodus sp.) and osteichthyans (Gyrolepis sp., Birgeria sp., and further indeterminate actinopterygians). Despite the large sample size, no remains of neoselachians have been found. The Ladinian Templomhegy Dolomite is dominated by durophagous hybodontiforms (Palaeobates angustissimus, ?Lissodus sp.), but the piscivorous hybodontid and the generalist ‘Polyacrodus’ sp. are missing, while in the fish fauna collected from the Carnian Mészhegy Formation indeterminate piscivorous hybodontids are the most common elements and durophagous forms are much less abundant. The dominance of piscivorous hybodontids in the Carnian Mészhegy Sandstone could be related to the global decrease of diversity of marine fish-eating reptiles (e.g., nothosaurs) or to a change of paleoenvironmental conditions. The present study improves our knowledge on the poorly known Triassic vertebrate faunas of the Tisza Mega-unit, which formed a segment of the passive Neotethys margin of the European Plate and shows an important example of a potential vertebrate faunal shift during the Middle to Late Triassic.     

Selenium and mercury concentrations in some fish species of the Madeira River, Amazon Basin, Brazil

Samples of 7 species of piscivorous, omnivorous, and herbivorous fish caught at 12 different sites on the Madeira River, Amazon Basin, were analyzed for selenium and mercury. Selenium was determined by anodic stripping voltammetry and mercury by cold vapor atomic absorption spectrophotometry. The means for selenium concentrations ranged from 0.49 to 3.11 nmol/g and for mercury from 0.41 to 6.66 nmol/g depending on the fish species. The molar ratios of Hg:Se increased according to the fish trophic level. Piscivorous species had the highest mean ratio (4.0) and herbivorous species the lowest (0.9). There was a positive and statistically significant correlation between selenium and mercury concentrations for the herbivorous species (r = 0.716;p = 0.0088) not seen for omnivororus and piscivorous species (r = -0.2032;p = 0.3407). These findings are significant for the fish-eating population of the Madeira River because the ingestion of mercury would always be in excess of selenium.     

Anthropogenic impact of mercury accumulation in fish from the Rio Madeira and Rio Negro rivers (Amazonia)

Fish is an important concentrator of mono-methyl mercury and the main route to human contamination. We compared fish Hg bioaccumulation (within similar weight ranges) in two Amazonian river habitats during high-water seasons. The Rio Madeira has been greatly impacted by agriculture, alluvial gold extraction, and a hydroelectric reservoir, whereas the Rio Negro is much less affected by these human activities. The species at the top of the food web, Hoplias malabaricus (piscivorous; 80-668 ng Hg/g) and Cichla spp. (piscivorous; 42–747 ng Hg/g) showed the highest range of Hg concentrations. Nonpiscivorous species with comparable weight range, such as Potamorhina latior (detritivorous; 20–157 ng Hg/g) and Myleus torquatus (herbivorous; 2–182 ng Hg/g), had lower Hg concentrations. Triportheus elongatus (omnivorous; 5–350 ng Hg/g), with the lowest weight range, also showed a low range of Hg concentrations. Despite the Rio Madeira's higher sediment load as well as environmental impacts (deforestation, agriculture, hydroelectric reservoir, and alluvial gold mining) on natural Hg release, fish Hg bioaccumulation was no different between the two river habitats for nonpiscivorous species. In this small observational study only the species at the top of the food web (M. torquatus, Cichla spp, T. elongatus) showed higher mean Hg concentrations in the Rio Madeira than the dominantly wilderness habitat of the Rio Negro.     

Musculature of the ovipositor of Lenitovena trigona (Matsumura) (Diptera, Tephritidae) with reference to the larval saprophagy

The larvae of most Tephritidae are endobiotic in various living plants and are therefore convenient objects for analysis of the associations of this dipteran family with seed plants. The structure of the sclerites and musculature of the ovipositor of Lenitovena trigona (Matsumura) a Far Eastern tephritid of the tribe Acanthonevrini with initially saprobiont larva, was investigated to facilitate understanding of the morphological changes in the adults associated with larval shift from saprophagous to herbivorous habit. Differences between the ovipositor of L. trigona and those of species of the genera Urophora, Ceratitis, and Rhagoletis with endophytic larvae have been found; the ovipositor musculature of these genera has been described by Dean (1935), Nanna (1938), and Berube and Zacharuk (1983).     

Extant and extinct forms of arctic charr Salvelinus alpinus (L.) complex from the Leprindo lake system (Transbaikalia): Differentiation in life history, morphology, and genetics

Interconnected lakes Bol’shoe Leprindo and Maloe Leprindo in Transbaikalia hosted large (extinct) and dwarf charr forms. Rarely “small” individuals intermediate in size between these forms are caught. In order to assess morphological, ecological, and genetic differentiation of sympatric charr forms and parapatric charr populations we studied their meristic and morphometric characters, feeding, breeding, and growth; we also investigated variation at 8 microsatellite loci using DNA isolated both from contemporary and historic samples. Profound differences were found between large and dwarf charr in growth rate, feeding (piscivores and highly specialized zooplanktivores, respectively), spawning time, and morphology. Dwarf charr from the two lakes demonstrate minor differences in morphology and growth rate. “Small” individuals are morphologically similar with dwarf charr and spawn together with them, they are recruited from dwarf form in late ontogeny as the result of transition to piscivorous feeding and growth acceleration. Microsatellite analysis showed that: (1) large and dwarf charr forms display high degree of genetic differentiation and reproductive isolation; (2) dwarf charr from interconnected lakes belong to different isolted populations; (3) “small charr” are genetically identical with dwarfs. The degree of ecomorphological and genetic differentiation between large and dwarf forms places charr from Leprindo Lakes among the most strongly differentiated Arctic charr forms’ flocks known at the vast range of S. alpinus complex.     

First feeding and subsequent growth performances in piscivorous larvae of Chinese perch Siniperca chuatsi (Perciforms: Sinipercidae)

The success of first feeding is influenced by many factors, such as prey availability, and is critical to subsequent larval growth performances. To test the advantages of prey exposure before complete yolk absorption in piscivorous larvae, feeding incidence and specific growth rate were longitudinally measured in Chinese perch Siniperca chuatsi larvae first fed at different ages. The results showed that Chinese perch larvae were able to capture live piscine prey at 4 DAH (days after hatching), 1 day before complete yolk absorption. The feeding incidence and specific growth rate were higher in larvae first fed at 4 DAH than in larvae first fed at 5 or 6 DAH. These results indicate that prey exposure experience can facilitate the onset of first feeding, and that successful exogenous feeding, even before complete yolk absorption, is important for growth performances of piscivorous fish larvae.     

Factors affecting the establishment success of the invasive piscivorous chub in small irrigation ditches in northern Kyushu,Japan

Habitat matching is an important factor for the establishment of alien fishes in recipient environments. The piscivorous chub, Opsariichthys uncirostris uncirostris, originally exclusively inhabited large water areas; however, the species has been introduced and established in small irrigation ditches on Kyushu Island. The evaluation of the habitat use of the piscivorous chub suggested that this alien fish uses the lentic-type irrigation ditches as a nursery ground and the lotic-type ditches as a spawning ground. This finding implies that the establishment of the piscivorous chub may require connectivity between lentic and lotic habitats.     

Life cycle of Anthracophora rusticola (Coleoptera: Cetoniidae) from the commensal nests of Chinese Sparrowhawks (Accipiter soloensis)

Commensal breeding habits of the Anthracophora rusticola (Coleoptera: Cetoniidae) in stick nests of carnivorous, piscivorous, and omnivorous birds were recently reported, but the detailed life history of the scarab beetle has not been thoroughly elucidated. To understand the breeding cycle of the declining A. rusticola related to that of nesting Chinese sparrowhawks (Accipiter soloensis) in Korea, we examined six sparrowhawk nests from 2005 to 2008 and reared larvae and cocoons in a cage in 2008. Each sparrowhawk nest hosted 11.3 ± 3.0 larvae and cocoons, implying that sparrowhawk nests might be the most important nesting resource of the beetles in Korea. The beetles may lay their eggs between late May and early July after nest building by sparrowhawks. Larvae were observed from July to August in the sparrowhawk nests, and adult beetles emerged in September after a mean pupal period of 25.5 days. Our results on the coinciding breeding of two commensal taxa over three months from May to September may provide key information regarding the life history of the commensal scarabid beetle and potential causes of the concurrent decline of both taxa in Korea.     

A tortricid moth of Cydia sp. (Lepidoptera: Tortricidae) boring into thorns of Gleditsia japonica Miq. (Fabaceae) in Japan

Plants defend themselves using various physical structures, including spines and thorns. However, some herbivorous insects can make use of defensive structures as food sources. A tortricid moth larva in the genus Cydia bores into thorns of the endangered Japanese honey locust Gleditsia japonica. The larva may escape predation by using the thorns as protection. A survey of sharp plant structures was proposed.     

Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae) use of Opuntia host species in Argentina

A central aspect in biology and ecology is to determine the combination of factors that influence the distribution of species. In the case of herbivorous insects, the distribution of herbivorous species is necessarily associated with their host plants, a pattern often referred to as “host use”. Novel interactions that arise during a biological invasion can have important effects on the dynamics of that invasion, especially if it is driven by only a subset of the genetic diversity of the invading species. This is the case of the wellknown South American cactus moth, Cactoblastis cactorum, a successfully used biological control agent of non-native Opuntia cacti in Australia and South Africa, but now threatening unique cactus diversity and agriculture in North America. We studied the patterns of host plant usage by and host plant availability for C. cactorum under field conditions in Argentina, covering the geographical range of the four C. cactorum phylogroups and the recently documented southern distribution. We also assessed female preference and larval performance under laboratory conditions. Cactoblastis cactorum showed a geographical pattern of host use in its native range that was related to host availability. Laboratory assays of female preference showed some degree of preference to oviposit on O. ficus-indica, O. leucotricha and O. quimilo, but it was not positively correlated with the performance of larvae. These findings contribute to the further comprehension of the host use dynamics of C. cactorum in the insects’ native range, and could provide useful information for assessing the risk and future spread of this insect in North America.     

Estimates of daily mortality from a neascus trematode in age-0 shortnose sucker (Chasmistes brevirostris) and the potential impact of avian predation

Parasites may be an important component of early life mortality in fishes, but assigning part of total mortality to parasites is difficult. The Chapman-Robson mortality estimator is a robust and potentially valuable way to quantify the added mortality of parasites when age data are available. We used daily age data and the Chapman-Robson catch-curve procedure to estimate daily mortality for 15 years in juvenile age-0 shortnose suckers (Chasmistes brevirostris), and for 6 years, the daily mortality of fish with and without black spot infection, a trematode whose final host is a piscivorous bird. Infected fish always had higher mortality rates than uninfected fish, and for 3 years when those differences were significant, the added daily mortality for infected fish was 3.6–3.7 %. Based on the proportion infected each year, and for durations of 15–50 d, juvenile populations were 18.3–38.6 % lower than they would have been without black spot infections. There were no significant differences in growth between infected and uninfected fish in most years and little indication of a direct metabolic impact of infections. Thus, this added mortality, primarily in July and August, seemed unlikely to be an indirect result of infection and was most likely due to predation. The source of that predation is unknown but the parasite’s final hosts, piscivorous birds, seemed the most obvious candidate for this added mortality.     

Predation Risk,Resource Quality,and Reef Structural Complexity Shape Territoriality in a Coral Reef Herbivore

For many species securing territories is important for feeding and reproduction. Factors such as competition, habitat availability, and male characteristics can influence an individual’s ability to establish and maintain a territory. The risk of predation can have an important influence on feeding and reproduction; however, few have studied its effect on territoriality. We investigated territoriality in a haremic, polygynous species of coral reef herbivore, Sparisoma aurofrenatum (redband parrotfish), across eight reefs in the Florida Keys National Marine Sanctuary that were either protected or unprotected from fishing of piscivorous fishes. We examined how territory size and quality varied with reef protection status, competition, predation risk, and male size. We then determined how territory size and quality influenced harem size and female size to understand the effect of territoriality on reproductive potential. We found that protected reefs trended towards having more large predatory fishes and that territories there were smaller but had greater algal nutritional quality relative to unprotected reefs. Our data suggest that even though males in protected sites have smaller territories, which support fewer females, they may improve their reproductive potential by choosing nutritionally rich areas, which support larger females. Thus, reef protection appears to shape the trade-off that herbivorous fishes make between territory size and quality. Furthermore, we provide evidence that males in unprotected sites, which are generally less complex than protected sites, choose territories with higher structural complexity, suggesting the importance of this type of habitat for feeding and reproduction in S. aurofrenatum. Our work argues that the loss of corals and the resulting decline in structural complexity, as well as management efforts to protect reefs, could alter the territory dynamics and reproductive potential of important herbivorous fish species.     

Multitrophic web of insects associated with <Emphasis Type="Italic">Piptadenia gonoacantha</Emphasis> (Mart.) Macbr. (Fabaceae) and their relationship with resource traits

We describe for the first time the food web of insects associated with fruits and seed of Piptadenia gonoacantha (Fabaceae), and analyze their relationships with resource traits, such as biomass and fruit area. A total of 440 fruits of P. Gonoacantha were sampled in the city of Lavras, Minas Gerais, Brazil. We found twenty-one species of insects distributed in three trophic levels. The most widely sampled species was Acanthoscelides clitellarius (Coleoptera, Chrysomelidae, Bruchinae), the main consumer species of seeds. It was also verified the presence of Lepidoptera larvae consuming both seeds and the internal fruit tissue. Other species of herbivorous insects were found in low numbers. The food web was subdivided into one sub-web of 10 parasitoid species and one hyperparasitoid species associated to A. clitellarius and another one sub-web of four parasitoid species associated with Lepidoptera. For the parasitism rates, we obtained the following: 19.11% for the total food web, 17.93% for the A. clitellarius parasitism, and 36% for the Lepidoptera parasitism. The resource traits had influence on the oviposition behavior of A. clitellarius, where fruits with larger area showed more eggs of this species. Fruits with higher biomass showed greater abundance and richness of insects as well as more interactions. Seeds with higher biomass were more often used by herbivorous insects. The larval forms of Lepidoptera caused the greatest damage in seed biomass among herbivores. Seeds with parasitoids did not show a significant difference in biomass when compared to predated seeds.     

Three new Prototapirella species,Opisthotrichum janus,and Troglocorys cava add to Entodiniomorphida (Ciliophora,Trichostomatia) diversity in mountain gorillas in Rwanda

Recently, a high number of Entodiniomorphida species was discovered in Virunga mountain gorillas (Gorilla beringei beringei) in Rwanda compared to other primates. Thirteen species of five genera (Troglocorys, Gorilloflasca, Prototapirella, Troglodytella, and Opisthotrichum) were identified with 10 species in Gorilloflasca, Prototapirella, and Troglodytella being host-specific, to our current knowledge. The remaining three species have been described for other herbivorous mammals; Prototapirella gorillae for western lowland gorillas; Troglocorys cava for western lowland gorillas, chimpanzees, and guinea baboons; Opisthotrichum janus in the family Ophryoscolecidae is regarded as specific to African antelopes. Here, we show the first indication that wild herbivorous hindgut fermenting mammals might have rumen ophryoscolecids in the intestine sympatric with their native intestinal ciliates. We also describe three new Prototapirella species, P. sabyinyo, P. sulcata, and P. curiosa. The somatic ciliary zones of the three new species are atypical of Prototapirella while their buccal infraciliature is not different from that of other Prototapirella species.     

The selective advantage of avoidance of the predatory whelk Lepsiella vinosa (Lamarck) by Littorina unifasciata (Philippi)

The herbivorous snail Littorina unifasciata (Philippi) is widely distributed, and different species of predatory whelks occur in different parts of its range. At Coobowie, South Australia, L. unifasciata coexists with and avoids Lepsiella vinosa (Lamarck), while at Portobello, New Zealand, Littorina unifasciata similarly coexists with and avoids Lepsiella scobina albomarginata (Deshayes). By transporting Lepsiella vinosa from Coobowie to Portobello it was shown that Littorina unifasciata from the latter population did not avoid this foreign species but were captured, drilled and eaten by it.     

杭州湾北岸大型围隔海域人工生态系统的能量流动和网络分析

根据2006年在杭州湾北岸大型围隔海域进行的生态调查数据,利用EwE软件构建围隔海域人工生态系统的能量流动模型.模型由13个功能组构成,分别是肉食性鱼类、底栖捕食鱼类、浮游动物性鱼类、草食性鱼类、蟹类、虾类、软体动物、底栖动物、肉食性浮游动物、植食性浮游动物、大型藻类、浮游植物和有机碎屑,每一组都代表在生态系统中具有相似地位的有机体,基本覆盖了该人工生态系统能量流动的主要过程.能量流动分析表明,围隔海域人工生态系统中能量流动主要以碎屑食物链途径为主,其中植食性浮游动物在能量从低级向高层次转换中起关键作用.人工生态系统的营养级范围为1.00～3.90级,系统的能量流动主要有6级,来自初级生产者的能流效率为9.4%,来自碎屑的转换效率为9.8%,平均能量转换效率为9.6%.经生态网络分析,直接来源于碎屑的比例占总流量的57%,而直接来源于初级生产者的比例为43%,生态系统特征参数:总初级生产计算量/总呼吸量(TPP/TR)、系统物质和能量循环率(FCI)和系统聚合度(A)值分别为2.672、0.25、0.315,表明围隔海域人工生态系统目前正处于发育时期.该研究为首次利用Ecopath模型分析大型围隔海域人工生态系统的结构和能量流动,旨在为富营养化近岸海域的生态修复提供理论依据.     

The food-finding orientation mechanism of Biomphalaria glabrata (Say)

An experimental procedure involving the use of time-lapse cinematography for accurately recording pathways was used to investigate the responses of Biomphalaria glabrata (Say) to a stimulus source of plant chemicals. This allows a more detailed analysis of the orientation mechanism than is the case with the Y-maze method. Snails of this species, which are essentially herbivorous, respond either by klinotaxis or tropotaxis or both to a source of plant chemicals. It was not possible to demonstrate the involvement of kinesis in the orientation mechanism.