A new species of Ilyocryptus (Crustacea: Anomopoda) from Bafra Balikgölü, Turkey

A new species of Ilyocryptus Sars from Bafra Balikgölü in Samsun, is described and figured. The shape and armature of Ilyocryptus samsuni n.sp. resembles I. sordidus (Liévin), but I. samsuni n.sp. differs from I. sordidus (Liévin) by the absence of ramified setae along the valve rims, and the occurrence of complete moulting.This study was supported by Hacettepe University Research Foundation, Project HÜAF 85 01 007 03.This study was supported by Hacettepe University Research Foundation, Project HÜAF 85 01 007 03.     

Banana defence responses to Cosmopolites sordidus feeding and methyl jasmonate application

Each year 25–75% of banana and plantain yields are lost because of rhizome damages caused by banana weevil (Cosmopolites sordidus) in growing regions of sub‐Saharan Africa. However, the specific plant defence response of the rhizome tissue in relation to the C. sordidus attack is unknown. Consequently, in this study, we evaluated whether plant defence substances in the rhizome are correlated with the degree of larval damage and whether applications of methyl jasmonate (MJ) elicit a greater induction of the plant defence potential against C. sordidus. Moreover, we attempted to reveal cellular modifications in response to the root feeding herbivore through histochemical staining. The banana cultivars “Km5” and “Mbwazirume” with tolerance and susceptibility to C. sordidus, respectively, were used in a pot experiment to evaluate percent rhizome damage, leaf chlorophyll content, total phenolic content (TPC), antioxidant capacity and cell morphology in response to C. sordidus attack and/or MJ applications compared to untreated control plants. We found that C. sordidus‐induced rhizome damage was 30% in the susceptible cultivar but less than 5% in the tolerant cultivar. The percent rhizome damage was not related to leaf chlorophyll content but showed a significant negative linear relationship to both TPC and antioxidant capacity. Larvae feeding induced a considerably greater increase of polyphenolic defence compounds in Km5 than in Mbwazirume; however, this response was opposite in the MJ treatment, suggesting that the phytohormone induced the susceptible plant to invest more into the synthesis of defence chemicals that in turn lead to reduced C. sordidus damage. Tissue staining demonstrated a greater deposition of lignin and suberin in C. sordidus challenged rhizome, presumably to seal off healthy tissue with a physical barrier from continued pest attack. It is concluded that MJ induces polyphenolics in susceptible Mbwazirume banana that reduced C. sordidus damage.     

Redescription of Ilyocryptus sarsi Stingelin, 1913

Ilyocryptus sarsi Stingelin, 1913, earlier regarded as a subspecies of I. sordidus Liévin, 1848, is a valid species, relatively common and widely distributed in South America. It is here redescribed based on material from a number of localities in Brazil. The type specimen is lost, and therefore a neotype is selected from Sars' (1901) specimens, hatched from dried mud from Ipiranga, Paraná, Brazil. Differences between I. sarsi, I. sordidus and some other species are indicated. Recent problems in the systematics of the sordidus-group are discussed. The validity of all species in the sordidus-group described after Liévin and Stingelin is in need of checking.     

A new species of Ilyocryptus (Cladocera: Macrothricidae) from Turkey

A new species of Ilyocryptus Sars from Çildir Lake in Kars is described and figured. In external morphology, Ilyocryptus anatolicus n. sp. resembles partly I. sordidus (Liévin) and I. spinosus tifter, but it shows several morphological differences in shape and armature of the postabdomen and in the defensive spines on the posterior margin of the carapace.     

Invaded habitat incompatibility affects the suitability of the potential biological control agent Listronotus sordidus for Sagittaria platyphylla in South Africa

Sagittaria platyphylla (Engelmann) J.G. Smith (Alismataceae) was first recorded in South Africa in 2008 and is considered to be an emerging weed with naturalised populations occurring throughout the country. A biological control programme was initiated in Australia and surveys conducted between 2010 and 2012 yielded potential agents, including the crown feeding weevil, Listronotus sordidus Gyllenhal (Coleoptera: Curculionidae). The potential of L. sordidus as a candidate biological control agent against S. platyphylla in South Africa was examined. Although adult feeding was recorded on a number of plant species, oviposition and larval development indicated a narrow host range restricted to the Alismataceae. In South Africa, S. platyphylla populations are primarily found in inundated systems. However, laboratory studies showed that L. sordidus did not oviposit on inundated plants, potentially nullifying the impact of the insect on South African populations. It is suggested that even though L. sordidus is a damaging, specific agent, its limited impact on inundated plant populations in South Africa does not justify the inherent risk associated with the release of a biological control agent.     

Feeding selectivity,food assimilability and demand of the Baikal invader <Emphasis Type="Italic">Gmelinoides fasciatus</Emphasis> (Stebbing, 1899) in Lake Ladoga

Feeding selectivity and assimilability of the Baikal invader Gmelinoides fasciatus (Stebbing, 1899) in Lake Ladoga at feeding by various types of plant and animal food have been studied experimentally. The food demand has been assessed at different assimilation levels. Freshwater shrimp G. fasciatus has been shown to have distinct selective capacity with respect to different kinds of plant and animal food.     

Preference of Cosmopolites sordidus for fusarium wilt-diseased banana plants

The objective of this study was to understand the role of Cosmopolites sordidus in the dispersal of Fusarium oxysporum f. sp. cubense race 1 (Foc) and more specifically to determine whether C. sordidus is preferentially attracted to Foc-contaminated banana plant material vs. Foc-free material. The attraction of C. sordidus to healthy and Foc-contaminated Gros Michel banana bulbs and pseudostems, as well as to pure cultures of Foc, was compared using four-choice olfactometers. Males and females were studied separately. After storage in a dark room, weevils were placed in the central chamber of olfactometers. After 15 min, the orientation of each of the weevil was determined according to the food source located in each of the four peripheral chambers of the olfactometer. Overall, 560 olfactometer assays were carried out. Weevils were found to prefer Foc-infected plant tissues. Weevil preference was not significantly affected by weevil sex. The attraction of C. sordidus to Foc-contaminated plant material suggests that this insect could be important for the dissemination of Foc, especially in early stages of epidemics, when Foc-infected plants are scarce.     

Costs and Benefits of Food Foraging for a Braconid Parasitoid

The costs and benefits of food foraging for the insect parasitoid, Phanerotoma franklini Gahan (Hymenoptera: Braconidae), were examined. Feeding benefited P. franklini by increasing longevity, but did not influence egg maturation. Costs of feeding are represented by the time required to locate and consume food. Field observations of starved wasps revealed that wasps spent approximately 25% of their time grazing on substances on the surface of cranberry foliage. However, our initial laboratory tests to determine the value of these substances were inconclusive. We also examined how grazing behavior integrated with host foraging by comparing the attack rate of fed and unfed wasps held under different host densities. While feeding status did not affect the mean attack rate of wasps, starvation enhanced the probability that a wasp will engage in movement over the host plant foliage. We conclude that feeding benefits P. franklini by increasing longevity, that travel time to food sources is likely to be low, and that the observed food-foraging behavior does not appear to influence host-foraging efficiency.     

Control of foraging behavior of individuals within an ecosystem context: the clam Macoma balthica,flow environment,and siphon-cropping fishes

Macoma balthica (L.), an abundant clam, ubiquitous in temperate estuaries across the North Atlantic, is known to practice both alternative basic modes of feeding available to seafloor invertebrates. It either holds its feeding organ, the siphon, at a fixed position just above the sediment surface to filter out food particles suspended in the overlying water or else extends and moves its siphon around to vacuum up deposited food particles on the sediment surface. Previous laboratory experiments have established an understanding of the role of current flow in dictating the choice of whether suspension or deposit feeding will be used by marine invertebrates with the facultative flexibility to choose. Faster flows imply greater fluxes of suspended particles so that the energetic rewards of suspension feeding are enhanced. Slower flows imply reduced renewal rates of suspended foods in the bottom boundary layers and enhanced deposition of food particles on the seafloor so that a switch to deposit feeding is favored. Like early optimal foraging theory, this understanding is based on energetic considerations alone without incorporation of broader implications of how population interactions such as predation and competition influence individual foraging behavior. Feeding behavior of Macoma balthica is influenced in the Neuse River estuary by both hydrodynamics and siphon-cropping by juvenile demersal fishes. Under conditions of identical concentrations of suspended particulates in the water column and organic contents of surface sediments, Macoma exhibited much higher levels of deposit feeding where currents were slower. In addition, exclosure and fish inclosure experiments demonstrated that juvenile demersal fishes influence feeding behavior of Macoma by cropping exposed siphons and inducing reduction in deposit-feeding activity. Effects of croppers were substantial in early to midsummer, when juvenile fish abundances were greatest in trawl samples from this estuarine nursery and before the growing fish exhibited ontogenetic changes in diet away from early concentration on bivalve siphons. Field experiments in which siphon-cropping fish were caged at varying distances off the bottom failed to detect any effective behavioral avoidance by Macoma of cropping in response to proximity of fish. One might have hypothesized that under high risk of cropping, Macoma would switch to suspension feeding and away from deposit feeding, the feeding method entailing more risk of losses to croppers because of greater siphon activity and greater extension of siphons on the sediment surface. Consequently, partial predation by siphon-cropping fishes greatly reduces deposit-feeding activity by Macoma balthica during summer as an apparent direct effect of disfigurement and reduction of siphons, the organ required for efficient deposit feeding. Information on current flows alone would not suffice to predict feeding behavior of this marine invertebrate: the influence of partial predation must also be included.     

Mechanisms of food selection in Daphnia

A conceptual behavioural and mechanistic Holling-type model of food selection in Daphnia pulicaria is derived from SEM observations with animals feeding on mixtures of spherical-cylindrical diatoms, oblongate green algae, and filamentous cyanobacteria, as well as ultrafine particles. The algae used were Stephanodiscus hantzschii (<- 6 µm length), Monoraphidium setiforme ( 20 µm), and Oscillatoria aghardii (strands, >- 80 µm). Cell (strand) selection can occur at any or all of three stages: (i) interception from the feeding currents, (ii) collection and channeling to the food groove, and (iii) compaction and transport to the mouth. During each stage, given equal initial cell densities, elongate cells are more likely to escape collection than spherical cells and are more likely to be rejected. In addition, filaments require increased handling time at stages (ii) and (iii) and promote entanglement with limb 5 and the postabdominal claw. Food is collected primarily with the aid of limbs 3 (and 4), but limbs 1 and 2 also intervene. Neither the leaky sieve hypothesis alone nor any other single-process hypothesis explains the observations on examined in corpore positions, morphology, and derived movements of the feeding limbs. Attachment and mucus appear to be important for the ingestion of bacteria and ultrafine particles.The model is consistent with many experimental results of differential feeding by Daphnia pulicaria on mixtures of variously shaped algae and other observations on Daphnia feeding behaviour. The paradigm of invariate, nonselective feeding by Daphnia is rejected.     

Feeding behavior of leaf-like juveniles of the round batfish <Emphasis Type="Italic">Platax orbicularis</Emphasis> (Ephippidae) on reefs of Kuchierabu-jima Island,southern Japan

Feeding behavior of juvenile batfish Platax orbicularis, which presents a mimic state resembling a fallen leaf drifting on the water surface, were surveyed on reefs off Kuchierabu-jima Island, southern Japan. The fish consistently showed drifting swimming patterns on the surface during daylight hours, and fed in a picking–feeding manner on algae covering floating materials or substrates near the water surface. The fish drastically switched to planktivory during the night as they actively hunted free zooplanktonic particles through combined ram and suction feeding manners. Stomach content analysis supported that the fish adopted different feeding tactics, targeting different food items between the two diel periods. Even without an abrupt change of habitat use, due to its mimic state, juveniles of P. orbicularis explore different preys according to their daily activities.     

Some Factors Governing Feeding Behavior of Homalozoon vermiculare (Ciliophora, Holotricha)

SYNOPSIS. Feeding activity of Homalozoon vermiculare on Paramecium and Blepharisma and on a number of non-living materials was compared in order to understand its feeding behavior and some of the factors governing it. During a given period it involves a series of feeding responses, each response being completed in 5 stages: (i) contact of prey or non-living particles with the oral rim of Homalozoon, (ii) ejection of toxin by Homalozoon, if the food is a living organism, (iii) paralysis of the prey, (iv) grasping, and (v) swallowing. The feeding activity of Homalozoon differs from one food to another and also on any one food at different times. These differences are governed by (i) the physiologic condition of Homalozoon and (ii) certain food characteristics. Its starvation, but not its developmental stage, markedly influences its feeding activity on any food. The food characteristics most important for feeding by Homalozoon are: (i) concentration of prey or non-living particles in the medium, insuring their adequate contact with the organism's mouth, (b) susceptibility of living organisms to paralysis by the toxin, (c) suitability of particle size for accommodation in the organism's mouth, and (d) suitability of the food material to stimulate the grasping and swallowing responses. Homalozoon much prefers Paramecium to Blepharisma on account of (i) a greater susceptibility of Paramecium to paralysis by the toxin, and (ii) certain differences in the chemical characteristics of the certain proteins, particularly albumins, hemoglobin, etc., of the 2 organisms.     

Food,feeding and digestion in streptocephalus dichotomus baird (Crustacea: Anostraca)

Summary Gut analysis of Streptocephalus dichotomus revealed that the main source of food is phytoplankton. S. dichotomus is a non-selective filter feeder, taking in all the food-items carried in the feeding currents and passed through the midventral groove. The feeding currents are produced by the thoracic limbs.Feeding experiments have shown that the time taken for the passage of food is directly proportional to the number of days of starvation. Food intake of males did not significantly differ from that of females when fresh animals were used, as well as animals used after one day of starvation.Fresh males as well as females took in significantly more food than starved animals.The digestive enzymes such as carbohydrases, proteases and lipases are present in the gut. The optimal pH for amylase ranged between, 5.8 to 6.6, for protease 7.4 to 8.0 and for lipase 5.2 to 6.5.This work formed a part of the thesis submitted to the University of Madras, in 1970 for the award of the Degree of Doctor of Philosophy.     

Phagostimulation of Lytechinus variegatus (Lamarck) (Echinodermata: Echinoidea)

Artificial agarose foods containing either starch, glycogen, carragheenan, alginate, casein, gelatin, albumin, or peptones at a concentration of 1% dry weight were not phagostimulatory. Artificial foods containing sugars, especially galactose, at a concentration of 0.005 M were phagostimulatory. Of the common amino acids, only L‐phenylalanine was phagostimulatory at this concentration. The initiation of feeding postures (movement of the spines, tube feet, peristome, and Aristotle's lantern) of Lytechinus variegatus was little affected by the concentration of plant extracts. Many aspects of this behavior were attributable to physical rather than chemical stimulation. Feeding rates of L. variegatus upon artificial agarose foods containing either Thalassia testudinum or Gracilaria verrucosa were directly dependent upon plant tissue concentration. All artificial agarose food‐items were initially moved to the mouth and fed upon, however the time spent feeding was directly dependent upon plant type and tissue concentration. Retention of the artificial food‐items upon the test after feeding was not influenced by plant type or tissue concentration. Differences in consumption of foods by L. variegatus are determined by the degree of persistence in feeding upon encountered items and not be selection before initiating feeding or by retention of food‐items for subsequent feedings.     

Feeding Life Style of Redlegged Earth Mite, Halotydeus Destructor (Acari: Penthaleidae), in pastures and the role of broad-leafed weeds

Redlegged earth mite, Halotydeus destructor, is a major pest of pastures and crops in Australia, and also feeds on lower plants on the soil surface. Feeding behaviour is reviewed, and the role of Arctotheca calendula, capeweed, in determining occurrence and abundance in pastures is investigated. Mites fed more and produced more progeny on Trifolium subterraneum (subclover) than on capeweed in non-choice experiments. In pastures with mixed species three times more mites were feeding on subclover than on capeweed foliage. However, twice as many mites were found on the soil surface under pasture patches consisting mainly of capeweed than of subclover. Patches were selected on the basis of pasture height, irrespective of plant composition. Twice as many mites were found in populations under patches of tall than short pasture. The daytime relative humidity was higher in tall than short patches, and the temperature slightly lower, making tall patches a more favourable niche for these mites. Ninety per cent of H. destructor were on the soil surface, while 10% were feeding on the upper canopy of pasture. The proportion of each population that was feeding was greater on subclover than capeweed, and subclover was a more suitable food. In Australia H. destructor occurs in regions with mixed pasture species, grown in rotation with grain crops. The ability of H. destructor to utilize foliage of a range of plant species of differing suitability for food, while living mostly on the soil surface in niches favourable for survival, has enabled it to become very abundant.     

Cross habituation to feeding deterrents and acceptance of a marginal host plant byPieris rapae larvae

Sensitivity of the cabbage butterfly,Pieris rapae L. to feeding deterrents was compared for larvae reared on different food sources under laboratory conditions. Since cabbage-reared larvae normally reject nasturtium,Tropaeolum majus L., the effects of previous exposure to allelochemicals on larval acceptance or rejection of this plant were also examined. When compared with cabbage-reared larvae, nasturtium-reared larvae were less sensitive to feeding deterrents including cymarin, erysimoside and 2-O-β-d-glucosyl cucurbitacin E. Nasturtium-reared larvae were insensitive to chlorogenic acid, which was deterrent to cabbage-reared larvae. Feeding by larvae reared on a wheat germ diet was not deterred by these compounds. The results indicate that dietary experience can extensively affect larval sensitivity to feeding deterrents and that cross habituation of larvae to deterrents occurs in response to certain chemical constituents of nasturtium and wheat germ diet. Digitoxin, however, proved to be an exception. Larvae reared on either nasturtium or wheat germ diet were as sensitive to digitoxin as those reared on cabbage. Previous results have shown that rejectionof nasturtium by cabbage-reared larvae is due to the presence of strong feeding deterrents in this plant. However, more than 50% of 2nd instar larvae reared from neonate on cabbage leaves treated with strophanthidin, cymarin, erysimoside, digitoxigenin and digitoxin accepted nasturtium as a food source. 2-O-β-d-glucosyl cucurbitacin E, 2-O-β-d-glucosyl cucurbitacin I and rutin were also active in causing larvae to feed on nasturtium. Thus dietary exposure to unrelated plant chemicals can profoundly affect insect acceptance of a plant that contains feeding deterrents.     

Selectivity and Variability in the Diet of Milne-Edwards' Sifakas (Propithecus diadema edwardsi): Implications for Folivory and Seed-Eating

Propithecus diadema edwardsi combines a strategy of high selectivity for many food items with the use of more readily available and abundant foods. Selectivity is seen in relation to taxonomic affiliations of plants eaten, forest composition, and phenological patterns. Feeding time is concentrated on relatively uncommon species as indicated by high selection ratios. Annual and monthly dietary diversity is low, with food choices restricted to a relatively narrow set of species: a total of 82 and 73 plant species were eaten by the two groups of which, only 22 and 16% contributed >1% feeding time, however, these values fall with commonly reported ranges. Plant parts eaten varied widely from month to month, with overall variance in seed-eating higher than variance in young or mature leaf feeding. No correlation between percentage feeding time and food availability is significant; instead, monthly feeding patterns are better explained by the availability of particular plant species, which also supports a view of high selectivity in food choice. In contrast to selectivity for many seed, whole fruit, and new leaf sources, reliably abundant food sources appear to be leaves from lianas, epiphytes, and parasites, which were eaten in all focal months. While dramatic interannual differences in dietary composition in response to the absence of a preferred seed source highlight the interpretation of folivores as surviving food crunches by turning to readily available, poor quality resources, this strategy is not unique to folivores.     

A Phylogenetic Analysis of Ilyocryptus Sars, 1862 (Cladocera: Ilyocryptidae)

Kotov and Štifter (2006) revised the taxonomy of the genus Ilyocryptus Sars, 1862 (Branchiopoda: Anomopoda: Ilyocryptidae) and concluded that 28 species can be recognized as valid for the world fauna. In order to test phylogenetic relationships between the species and to contribute to a better understanding of the genus, a cladistic (using branch‐and‐bound search) analysis was conducted for 25 Ilyocryptus species (two of them with two subspecies). In total, 32 morphological characters were used. An evolutionary‐morphological interpretation of the results was also made. Phylogenetic analysis revealed that Ilyocryptus elegans is an earlier derived member of the genus, while other species are separated into two main branches: agilis ‐ and sordidus ‐lines (without reference to type of moulting). Species with incomplete moulting and species with complete moulting do not form separate clusters, suggesting an independent origin of incomplete moulting within different species groups. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)