Gypsy moth (Lymantria dispar) larval development and survival to pupation on diet plus extractables from green ash foliage

Gypsy moth, Lymantria dispar L., rate of larval development, molting, pupal weight and survival were studied on an artificial diet containing different concentrations of green ash ethyl acetate extractables (EtOAc Exts). Insects were reared on experimental diets from egg to pupa. Addition of EtOAc Exts to artificial diet significantly prolonged larval development and reduced their survival compared to larvae reared on control diet. Weights of pupae were significantly reduced when larvae were reared on diet containing the lowest dosage of EtOAc Exts (i.e., 0.01%) versus on control diet. EtOAc Exts in diet (e.g., 0.01, 0.06 and 0.2%) frequently caused incomplete ecdysis which invariably resulted in larval death. Impaired feeding, locomotion and excretion are likely causes of death. The combination of these results with our earlier findings of repellents and feeding deterrents against gypsy moth larvae (GML) in green ash foliage shows that the non-host status of green ash to the highly polyphagous GML involves three orders of chemical defense: repellents, feeding deterrents and inhibitors of nutritional and developmental physiology. As the insect becomes sequentially exposed to these orders of defense, it incurs higher costs because the adverse effects become less reversible.     

“Male factors” in ticks: their role in feeding and egg development

Summary

Female ticks of the family Ixodidae utilize their salivary glands as the major organs for fluid balance, secreting back into the host a dilute saliva. Feeding is composed of three phases: a preparatory phase (1–2 days) during which the tick establishes the feeding lesion, a slow phase (~7 days) during which body weight increases 10-fold, and a rapid phase (~1 day) in which body weight increases a further 10-fold. Following engorgement, the salivary glands are resorbed by an autolytic process triggered by an ecdysteroid hormone. If a female is removed from the host prior to repletion, her subsequent behaviour depends mostly on two factors: the degree of engorgement achieved and whether or not she has mated. If removed during the preparatory or slow phase of engorgement, the salivary glands are not resorbed, the tick will lay virtually no eggs and she will reattach to a host if given the opportunity, all of this irrespective of whether she is virgin or mated. If removed during the rapid phase of engorgement, however, mated females will not reattach to a host even if given the opportunity. Instead, they will resorb the salivary glands within 4 days post-removal and lay a batch of eggs. Virgin females removed after exceeding 10-fold the unfed weight likewise refuse to resume feeding if given the opportunity, but salivary gland reabsorption is delayed (to 8 days post-removal); if any eggs are laid, they are infertile. A number of chemical “factors” entering the female during copulation influence her feeding behaviour and egg development. Here we discuss the complexities of these interactions and suggest how they might be adaptive to ticks in nature.     

早期断奶对犊牛生产性能和母牦牛繁殖性能的影响

本试验旨在研究早期断奶对犊牛生产性能和母牦牛繁殖性能的影响。试验组采取"全哺乳+早期诱饲+补饲+放牧+早期断奶"的模式进行饲养,对照组采取传统放牧。实验表明:试验组犊牛5月龄实现早期断奶,体重极显著高于对照组(p<0.01)((53.13±12.34) kg VS (23.44±9.38) kg);试验组犊牛7月龄时体重达71.42 kg,比对照组提高了1.36倍;血液检测分析:与对照组相比,试验组显著提高了牛表皮生长因子(p<0.05);12月龄时体重极显著高于对照组(p<0.01)((87.25±23.43) kg VS (39.51±17.28) kg);当年生犊牦牛实施早期断奶,母牦牛进入下一个繁殖周期,其"一年一胎"比例达68.6%。因此,早期断奶尚未影响犊牦牛生长发育,同时有利于母牦牛年产犊的提高。     

Selective feeding by shredders on leaf-colonizing stream fungi: comparison of macroinvertebrate taxa

Summary Laboratory experiments were conducted to examine the effects of fungal species composition of leaf detritus on the feeding of distantly related macroinvertebrate shredders. Preferences of shredders representing three orders of insects (Diptera: Tipulidae; Plecoptera: Pteronarcidae; Trichoptera: Limnephilidae and Calamatoceridae) and one each of gastropods (Basommatophora: Planorbidae) and crustaceans (Amphipoda: Gammaridae) were compared. Shredder preferences were based on consumption of leaves separately colonized by one of eight species of aquatic hyphomycetes. The feeding patterns of the invertebrates ranged from lack of feeding to heavy consumption of fungal-colonized leaves. Where consumption occurred, rank orders of preference and degree of selectivity differed among invertebrate shredders. Differences in preferences together with relationships between degree of selectivity and the relative mobility and digestive specializations exhibited by shredders suggest that the exploitation of fungal-colonized leaf detritus by different taxa is affected by phylogenetic constraints. Our results suggest that fungal species composition affects the feeding of a variety of shredders and that fungal species composition may be as important as degree of conditioning in determining food selection by shredders.     

Feeding strategies of Japanese monkeys against deterioration of habitat quality

Field observations of the feeding behaviour of Japanese monkeys were carried out from autumn to winter on Kinkazan Island which is covered with cool temperate forest. As a result, the following two points became clear: (1) the available food items were fixed for a long time; and (2) the habitat quality deteriorated monotonously because the monkeys themselves or their competitors, such as wild mice, utilized the food resources. Against the decrease in food intake caused by this deterioration of the habitat quality, the monkeys controlled the decrease in food intake by employing the following strategies: (1) they recovered their feeding speed by exploiting new food patches (patch-increase strategy); (2) they extended the time spent on feeding (time-extension strategy); and (3) they changed their food (food-change strategy). The former two strategies operated earlier than the third one.     

Life history traits of shrimps (Decapoda: Palaemonidae) of Amazonian inland waters and their Phylogenetic interpretation

Amazonian shrimps (Decapoda, Palaemonidae) of several genera from the generally nutrient‐poor, acid waters of the Rio Negro basin show two different breeding patterns: in the annually inundated (Jan./Feb. to Sept./Oct.) lowland forest (= “igapó") they breed during a period with rising and high water levels only (Dec. to July); in the headwater streams draining the “terra firme”; (= regions not subject to annual inundations), the same species breed continuously the year round. All species from these nutrient‐poor and hence, plankton‐deficient, waters have abreviated life cycles with 1–3 benthic larval stages; this includes several Macrobrachium species. However, Macrobrachium amazonicum from the plankton‐rich floodplain lakes, which are fed by the richer water of the Amazon river, maintains the marine pattern of development with numerous stages of filter‐feeding, planktonic larvae. Phylogenetic convergence (several genera developing independently the same adaptive pattern) and divergence (the same genus/species exhibiting different patterns in different environments) are discussed in relation to recent, general molecular genetics.     

Norcantharimide analogues possessing terminal phosphate esters and their anti-cancer activity

A family of norcantharidin analogues possessing a terminal alcohol (ethanol, propanol, butanol, pentanol, hexanol and cyclohexanol) moiety were treated with either chlorodiethyl, chlorodiphenyl or chloro-bis-trichloroethyl-phosphate to afford highly focused libraries of the corresponding phosphate esters. Subsequent biological screening against a panel of nine human cancer cell lines identified a trend between the ease of phosphate unmasking (phosphate ester hydrolysis) and cell death. The most potent analogues possessed either a diphenyl or a bis-trichloroethyl moiety. The effect of alkyl spacer was also examined with the hexyl analogues typically more potent. 4-Aza-4-(3-{bis(2,2,2-trichloroethyl)phosphate}propyl)-10-oxatricyclo[5.2.1.0]decane-3,5-dione (10b) was the most potent analogue synthesised with an average GI(50) of 11 μM across a panel of nine human carcinoma cell lines: colon carcinoma (HT29 and SW480); breast carcinoma (MCF-7); ovarian carcinoma (A2780); lung carcinoma (H460); skin carcinoma (A431); prostate carcinoma (DU145); neuronal carcinoma (BE2-C) and brain carcinoma (SJ-G2). This represents a fivefold improvement in anti-proliferative activity relative to the lead, norcantharidin.     

Effect of liquid feeding at different water-to-feed ratios on the growth performance of growing-finishing pigs

The study examined the growth performance of pigs offered liquid feed or dry feed on either a restricted or an ad libitum basis, and whether their growth performance was further influenced by the water-to-feed ratio. The study was split into two parts to enable unrestricted (trial 1; n = 64) and restricted (trial 2; n = 48) feeding to be compared. Male pigs were randomly allocated to six dietary treatment groups. A standard dry pellets diet (D) was offered either as: (i) unrestricted ration (UR); (ii) restricted ration (R); or D soaked in water at a feed-to-water ratio of (iii) 1 : 1.5 restricted (1 : 1.5 R); (iv) 1 : 3 unrestricted (1 : 3 UR); (v) 1 : 3 restricted (1 : 3 R); or (vi) 1 : 3 restricted with the addition of lactic acid to adjust the feed to pH 4 (1 : 3(4) R). Liquid feeding improved (P < 0.05) average daily live-weight gain (ADG) and lean tissue growth rate (LTGR) in the 1 : 3 UR compared with DUR but did not alter feed conversion ratio (FCR). Within the R groups, ADG were greater in all of the 1 : 3 diets, whereas feed intake, and hence FCR, was lower (P < 0.001) in these groups when offered the R ration. In conclusion, liquid feeding has a beneficial influence on the performance of modern porcine genotypes during the growth/finishing phase and this is further modulated by the water-to-feed ratio.     

Instars ofMicroplitis rufiventris [Hym.: Braconidae] and their relative developmental speed under different photoperiods

The internal parasiteMicroplitis rufiventris Kok. passes through 3 instars but moults 3 times within its host. The last moult occuring just at emergence time. The morphology of the egg and larval stages of the parasite are discussed. At 27°C and a photoperiod of 6 h (6L:18D) the endo-developmental cycle of the parasite can summarize as follows: Egg 18–24 h; instar 1,4 days (fighting phase 48 h; feeding phase 30–48 h); instar 2, 12–18 h and instar 3,3 days. The effect of different photoperiods on the relative speeds of the endo-developmental stages of the parasite at each of 30, 25, 20°C were carefully studied. At the first 2 temperatures, the short photoperiod (6L:18D) accelerated the development of larval instars, while both of 18L:6D or 0L:24D slowed down the development. Under the latter photoperiods some larvae failed to moult and had emergence problems. The influence of photoperiod is significantly noticeable at 20°C. The incubation period of the egg-stage was prolonged significantly at 18L:6D and the development of larval instars was significantly faster and refined at 6L:18D. The factor(s) inhibiting the development of the egg-stage perhaps differ from those affecting the larval development. The ventral area of the host mid-gut among malpighian tubes seems to be where the surplus parasite larvae are eliminated by physical attack. A physiologically suppressed parasite larva is able to attack its developed competitor of the same age. Teratocytes cells perhaps play a part in eliminating the surplus parasite larvae by physiological suppression.     

阿魏传粉昆虫及其访花行为的初步研究

对新疆阿魏访花昆虫种类、昆虫访花频次、昆虫访花时间及昆虫访花行为进行了初步研究。在盛花期观察中,(1)发现有5目、23科、45种昆虫进行了访花,其中传粉昆虫4科7种,均属蜜蜂总科;(2)各类昆虫访花频次在不同观察时间变化较大,传粉蜜蜂仅出现在其中一个观察日中;(3)不同种类昆虫在花上的停留时间差异很大,传粉昆虫停留时间很短,鞘翅目昆虫停留时间最长。进入始果期后,昆虫的访花行为是围绕花盘的蜜腺展开的。     

Effects of neem-treated aphids as food/hosts on their predators and parasitoids

Abstract:  Experiments were conducted in the laboratory and in greenhouses. Of three neem preparations sprayed upon eggs, only neem oil (NO) exerted a negative impact on the hatching rate of Coccinella septempunctata and Chrysoperla carnea . First instar larvae of Episyrphus balteatus proved to be highly susceptible, when feeding 24 h on aphids sprayed with neem kernel water extract (NKWE). First instar larvae of C. septempunctata showed a very high mortality when feeding on aphids sprayed with different neem preparations. Aphid feeding and live span was reduced. When NKWE had been applied to the soil, the mortality of larvae of E. balteatus and C. septempunctata were lower, when feeding on aphids. Second instar larvae of C. septempunctata were far less susceptible when feeding 48 h on neem-sprayed aphids than first instars; the time of their development was prolonged, and aphid consumption reduced. Larvae of C. carnea proved to be less susceptible, when feeding on neem-sprayed aphids, than E. balteatus and C. septempunctata . In C. carnea , however, significant influences were also observed in aphid consumption, time of development, mortality, longevity, and rate of deformity. NO, containing a very low concentration of azadirachtin A, had stronger negative effects than NeemAzal-T/S^®, in all observations. In the parasitoid Diaeretiella rapae , NKWE application to the soil induced negative reactions, when aphids on these plants were parasitized: low percentage parasitization, lowered mummy weight, low emergence rate of adults of F1 and even of F2. Foliar sprays of NKWE had less severe effects in this parasitoid species. The results are discussed with regard to their theoretical and practical significance.     

Ediacaran macroalgal holdfasts and their evolution: a case study from China

A macroalgal holdfast (root-like structure) anchored or grown into sediments is a key trait of metaphytes and eukaryotic algae. Various patterns and taphonomic variants of congeneric holdfasts are preserved on the bedding planes of black shales of the Ediacaran Wenghui biota in South China. The macroalgal holdfast, which commonly consists of a rhizome, rhizoid and pith (perhaps mechanical tissue), can be morphologically classified into ten types within four groups of rhizomes: bare rhizome holdfasts (Grypania, Tongrenphyton and Sectoralga-type holdfasts), canopy rhizome holdfasts (Gemmaphyton, Gesinella, Discusphyton and Baculiphyca-type holdfasts), pithy rhizome holdfasts (Zhongbaodaophyton and pithy-cone-type holdfasts) and differentiated rhizome holdfasts (Wenghuiphyton-type holdfasts). Analysis of the Precambrian macroalgal record indicates that rhizomes played a more important role in the evolution of macroalgal holdfast than rhizoids. The following evolutionary stages of development of macroalgal holdfasts are proposed: (1) growth of the basal thallus into sediments (Grypania-type holdfast); (2) development of a primitive (indistinct) rhizome from the base of a stipe or thallus (Tongrenphyton-type and Sectoralga-type holdfasts); (3) growth of a distinct rhizome with rhizoid (Gemmaphyton-type, Gesinella-type and Discusphyton-type holdfasts); (4) development of a pith in the stipe (Baculiphyca-type holdfast); (5) pith extension into the rhizome (Zhongbaodaophyton-type and pithy-cone-type holdfasts); and (6) rhizome differentiation and development of a complex holdfast system (Wenghuiphyton-type holdfast).     

Optimal foraging and community structure: implications for a guild of generalist grassland herbivores

Summary A particular linear programming model is constructed to predict the diets of each of 14 species of generalist herbivores at the National Bison Range, Montana. The herbivores have body masses ranging over seven orders of magnitude and belonging to two major taxa: insects and mammals. The linear programming model has three feeding constraints: digestive capacity, feeding time and energy requirements. A foraging strategy that maximizes daily energy intake agrees very well with the observed diets. Body size appears to be an underlying determinant of the foraging parameters leading to diet selection. Species that possess digestive capacity and feeding time constraints which approach each other in magnitude have the most generalized diets. The degree that the linear programming models change their diet predictions with a given percent change in parameter values (sensitivity) may reflect the observed ability of the species to vary their diets. In particular, the species which show the most diet variability are those whose diets tend to be balanced between monocots and dicots. The community-ecological parameters of herbivore body-size ranges and species number can possibly be related to foraging behavior.     

The effects of trans trans methyl linoleate on the concentration of prostaglandins and their precursors in rat

Four groups of weanling male rats were fed a diet containing hydrogenated coconut oil (Treatment A); 9-trans, 12-trans linoleate (trans linoleate, Treatment B); an equal mixture of 9-cis, 12-cis linoleate (cis linoleate) and trans linoleate (Treatment C); and cis linoleate (Treatment D); respectively for 12 weeks. The level of dietary fat was 11% of calories. Only trace amount of eicosatrienoic acid (C20:3w6) was detected in tissues, (liver, platelets) of rats in Treatments A and B. The level of C20:3w6 in platelet lipids of Treatments C and D was 0.1 and 0.33% respectively. The level of arachidonic acid in rats on Treatments A, B, C and D was 2.0, 1.4, 14.1 and 17.6% for platelet lipids, respectively. The serum levels of prostaglandin PGE₁ for Treatments A, B, C and D were 1.10 ± 0.24, 0.22 ± 0.02, 3.51 ± 0.58 and 5.69 ± 0.59 ng/ml, respectively and 2.19 ± 0.85, 0.15 ± 0.03, 11.64 ± 2.63 and 24.89 ± 4.35 ng/ml for PGE₂, respectively. Thus feeding trans linoleate to rats apparently caused decreased biosynthesis of PGs resulting from decreased levels of precursor acids. This was apparently due to the inhibition of conversion of cis linoleate to longer chain polyunsaturated fatty acids. The results indicate that the availability of precursor acids is one limiting factor in PG biosynthesis in rats, and small differences in the level of precursor acids, affected by dietary trans fatty acids may cause large variations in amounts of PGs synthesized.     

The effects of trans trans methyl linoleate on the concentration of prostaglandins and their precursors in rat.

Four groups of weanling male rats were fed a diet containing hydrogenated coconut oil (Treatment A); 9-trans, 12-trans linoleate (trans linoleate, (Treatment B); an equal mixture of 9-cis, 12-cis linoleate (cis linoleate) and trans linoleate (Treatment C); and cis linoleate (Treatment D); respectively for 12 weeks. The level of dietary fat was 11% of calories. Only trace amount of eicosatrienoic acid (C20:3w6) was detected in tissues, (liver, platelets) of rats in Treatments A and B. The level of C20:3w6 in platelet lipids of Treatments C and D was 0.1 and 0.33% respectively. The level of arachidonic acid in rats on Treatments A, B, C and D was 2.0, 1.4, 14.1 and 17.6% for platelet lipids, respectively. The serum levels of prostaglandin PGE1 for Treatments A, B, C and D were 1.10 +/- 0.24, 0.22 +/- 0.02, 3.51 +/- 0.58 and 5.69 +/- 0.59 ng/ml, respectively and 2.19 +/- 0.85, 0.15 +/- 0.03, 11.64 +/- 2.63 and 24.89 +/- 4.35 ng/ml for PGE2, respectively. Thus feeding trans linoleate to rats apparently caused decreased biosynthesis of PGs resulting from decreased levels of precursor acids. This was apparently due to the inhibition of conversion of cis linoleate to longer chain polyunsaturated fatty acids. The results indicate that the availability of precursor acids is one limiting factor in PG biosynthesis in rats, and small differences in the level of precursor acids, affected by dietary trans fatty acids may cause large variations in amounts of PGs synthesized.     

REVIEW: Lycaenid-ant interactions of the Maculinea type: tracing their historical roots in a comparative framework

Parasitic relationships between lycaenid butterfly larvae and ants are contrasted with the more common, and ancestral, mutualistic butterfly-ant associations. Three types of lycaenid-ant parasitism can be recognized: (i) the Miletinae type (derived from predation on Homoptera); (ii) the Aphnaeini type (derived from obligate and specific mutualism or commensalism); and (iii) the Maculinea type (derived from facultative mutualism, only represented by the genera Maculinea and Lepidochrysops). Parasitic lycaenid-ant interactions are rare (37 confirmed recorded cases worldwide) and are mostly confined to single species, or small species-groups, in larger non-parasitic clades. Only the two genera representing the Maculinea type have undergone substantial radiation. Ant-parasitic lycaenids predominantly occur in highly seasonal habitats with an extended unfavourable dry or cold season. These observations suggest that (a) parasitic interactions are relatively unstable in evolutionary time, and (b) their evolution usually started with caterpillars seeking shelter in ant nests. Ecological and zoogeographical data for species of the Glaucopsychiti (of which Maculinea forms a part) are compiled and used to discuss the evolutionary origin of ant-parasitism in Maculinea butterflies in a comparative framework. These comparisons suggest that (a) Maculinea evolved from facultative unspecific ant-mutualists, (b) the loss of larval tentacle organs is primarily related to their endophytic feeding habits, (c) that Lamiaceae were the hostplants of ancestral Maculinea, and (d) that Maculinea evolved in eastern central Asia. Further phylogenetic and biogeographical analyses are required to quantitatively test these possibilities. © Rapid Science Ltd. 1998     

Natural transfer of helminths of marine origin to freshwater fishes with observations on the development of Diphyllobothrium alascense

Infective stages of helminths of 5 species that occur as adults in marine mammals were found in burbot, Lota lota (L.) (Gadidae), from the lower Kuskokwim River (southwestern Alaska): Diphyllobothrium alascense Rausch et Williamson, 1958; Pyramicocephalus phocarum (Fabricius, 1780); Corynosoma strumosum (Rudolphi, 1801); Corynosoma semerme (Forsell, 1904); and Pseudoterranova decipiens (Krabbe, 1878). Some larval stages were obtained also from smelt, Osmerus mordax dentex Steindachner, an anadromous fish important as prey of burbot. Burbot, which are freshwater fish, could become paratenic hosts of those helminths by means of at least 3 interactions: by consuming marine fishes in brackish waters at river mouths, by feeding on marine fishes that enter lower reaches of rivers, or by preying on anadromous fishes as they migrate up rivers. Consumption of burbot by people may result in infection by helminths of marine origin; of those recorded, only P. decipiens may be significantly pathogenic. Attempts to rear P. phocarum in dogs were unsuccessful. Plerocercoids of D. alascense, of very small size and found only in the gastric lumen of burbot, readily infected dogs. For study of their development, strobilae were obtained at intervals of 48 hr to 32 days postinfection. In heavy infections, some strobilae developed slowly, while others underwent rapid development.     

Orexins对小鼠摄食和能量代谢的影响

目的:探讨Orexins对小鼠摄食和能量代谢的影响。方法:将小鼠分为摄食组和代谢组,摄食组通过中枢置管,注射不同剂量(1、3、10 nmol)的orexin-A和orexin-B,观察它们对小鼠摄食以及肝柠檬酸合酶活性的影响。代谢组将小鼠置于代谢笼内,通过中枢注射orexin-A,观察小鼠在光照条件、黑暗条件、禁食条件下呼吸商和代谢率的变化。结果:与对照组相比,1 nmol和10 nmol orexin-A在注射后4小时内可显著刺激小鼠进食(P0.05),而3 nmol orexin-A对摄食量的影响并不明显,但能显著促进柠檬酸合酶活性。任何剂量的orexin-B对小鼠摄食都没有显示出刺激作用(P0.05)。在光照条件下,orexin-A可显著降低呼吸商(RQ),代谢率显著升高(P0.05);而在黑暗条件下,orexin-A对RQ没有任何影响,但代谢率显著升高(P0.05);但是给禁食小鼠中注射orexin-A可诱导RQ的短暂升高,代谢率显著升高(P0.05)。结论:Orexins对小鼠摄食与能量代谢可能有一定的调控作用。     

Feeding behaviour and efficiency of banana weevil (Cosmopolites sordidus) larvae on banana cultivars of varying resistance levels

Nutrient composition, secondary plant substances and other host quality characteristics govern resistance and influence herbivore feeding. The current study was carried out to compare aspects of feeding behaviour and food utilization of banana weevil (Germar) (Coleptera: Curculionidae) larvae feeding on banana cultivars with different levels of resistance. In the first study, penetration times of larvae into tissue of seven banana cultivars (two susceptible, three intermediate and four resistant) were compared. Day‐old larvae were placed on corm or pseudostem tissue of these cultivars and time taken to penetrate the tissue was recorded. Larvae generally took longer to tunnel into resistant cultivars, although Yangambi Km5 (resistant) did not fit this pattern. In the second set of studies, food consumption and growth of larvae were compared on cultivars: (i) Kisubi (resistant) vs. Atwalira (susceptible); and (ii) Mbwazirume (intermediate) vs. Kayinja (resistant). Day‐old larvae were offered weighed pieces of corm that were changed every 4–7 days. At each corm change, weights of the larvae, corms and frass were measured. Changes in corm and larval weight were calculated to determine larval growth and amount of tissue consumed. Larvae feeding on resistant cultivars had lower consumption and growth rates and longer developmental duration. It was concluded that low food consumption rates contribute to delayed development of larvae feeding on resistant cultivars. Differences between resistant and susceptible cultivars in food utilization may be of limited consequence for the cultivars tested. This is one step in identifying the factors influencing weevil development rates in cultivars of different resistance levels. If these factors are identified, they can be targeted in breeding for resistance.     

Comparative morphology and ecomorphology of the gut in European cyprinids (Telostei)

The patterns of coiling of the gut were compared in 22 species of Eurasian Cyprinidae. In selected species, also the length of gut and mucosal surface structure were compared. Piscivorous ( Aspius aspius ), planktivorous ( Abramis ballerus ) fishes as well as species feeding mainly on plankton and wind-borne' drift'( Alburnus alhurnus, Pelecus cultratus ) have the relatively shortest guts, with only a single loop. The same simple arrangement of a short gut is present in many euryphagous species with more or less carnivorous tendencies ( Abramis sapa, Alburnoides bipunctalus, Abramis brama, Blicca bjoerkna, Chalcalburnus chalcoides memo, Gobio gobio, Leuciscus cephalus, Leuciscus leuciscus, Rutilus rutilus, Scardinius erythrophthalmus. Tinea tinea, Vimba vimba ). Some benthivorous winnowers (oropharyngeal sorters) and species with herbivorous feeding tendencies have relatively long guts showing a more complex pattern of loops and coils ( Barbus barbus, Carassius carassius, Chondrostoma nasus, Ctenopharyngodon idella, Cyprinus carpio ). The goldfish, Carassius auratus , has the most complex coils. Scanning electron microscopy of the mucosal surface revealed five types of folding in the intestinal bulb which were only loosely related to feeding: 1, smooth surface ( Aspius aspius, Leuciscus cephalus, Vimba vimba ); 2, irregularly branching folds ( Alhurnus alburnus, Barbus barbus, Blicca bjoerkna, Chalcalburnus chalcoides memo, Leuciscus leuciscus, Rutilus rutilus, Scardinius erythrophthalmus ); 3, curl-like folds ( Tinea tinea ); 4, net-like folding pattern ( Abramis brama ); 5, honeycomb-like mucosal structure ( Cyprinus carpio ).