The brine shrimp Artemia sp. as alternative prey for rearing the predatory bug Macrolophus caliginosus

The predatory bug Macrolophus caliginosus, which is widely used in greenhouse crops, is limited in its application by its high price. An important factor in the cost is the high price of Ephestia kuehniella eggs, the prey used in their mass rearing. In order to reduce their price, alternatives to moth eggs are currently being investigated. The brine shrimp Artemia sp. is produced in large quantities in saline lakes and is fed as live food source to the larvae of a variety of marine and freshwater organisms. In this study, we tested Artemia sp. as prey for rearing M. caliginosus from two strains. We evaluated developmental and reproduction parameters of the predator when fed nauplii, enriched nauplii with a fatty acid, dry cysts and hydrated cysts, and were compared with those obtained when the predator was fed with E. kuehniella eggs. Nauplii had a significant reduction in survivorship, a delay in development of nymphs and a low reproduction of adults. Nauplii enriched with docosahexaenoic acid (DHA, 22:6n − 3), a common practice for larviculture of some marine fish species, resulted toxic to M. caliginosus nymphs and survival was quite low. On the contrary, either dry or hydrated cysts from the two strains tested of the brine shrimp produced the same nymphal survivorship, nymphal development time and weight and fecundity of adults as those obtained with E. kuehniella eggs. Demographic parameters of the eighth generation of the predator reared with cysts of the two strains, either dry or hydrated, were as good as those of moth eggs. We concluded that Artemia sp. cysts were a good substitution prey for the mass rearing of M. caliginosus.     

Diet of Buffy Tufted-Eared Marmosets (Callithrix aurita) in a Forest Fragment in Southeastern Brazil

The feeding ecology of the Atlantic forest marmosets (Callithrix spp.) in southeastern Brazil is poorly known, and few studies have focused on buffy tufted-eared marmosets, Callithrix aurita. We determined the food items and investigated the seasonal variation in the diet of a group of four Callithrix aurita in a 17-ha semideciduous forest fragment in southern Minas Gerais State, Brazil. We recorded daily feeding activities between October 1994 and September 1995 using scan sampling at 5-min intervals. The marmosets devoted feeding time to gums (50.5%), fruits (11%), and animal prey (38.5%) in a total of 499 records. Plant resources comprised 27 species from 16 families. They used Acacia paniculata (Mimosoideae, Leguminosae), the main gum source (82%), year-round. Maclura tinctoria (Moraceae) was the fruit species that they consumed most (22%). The marmosets preyed on caterpillars (33%), katydids (5%), and homopterans (4%). Feeding on fruits varied seasonally and was inversely related to gum feeding. Consumption of animal prey remained constant over the year. The wide and year-round dependence on gum suggests that Acacia may play a critical role in marmoset persistence in forest fragments.     

Diet-induced variations in fatty acid content and composition of two on-grown stages of Artemia Salina

Three species of microalgae, the freshwater Euglena gracilis and themarine Dunaliella salina and Tetraselmis suecica, were fed tothe brine shrimp Artemia salina in order to compare their suitabilityin terms of fatty acid enrichment, and their effect on the biometric parametersof the zooplankter. The fatty acid content and composition were analyzed for the post-larval and pre-adult stages of Artemia fed the algae and theresults compared to the initial content of unfed 24-hour post-hatch nauplii.Differences in the total fatty acid content occurred between the three stages,the fatty acid profile being determined by the composition of the diet. A decreasing trend for almost all the individual fatty acids occurred throughdevelopment from post-larva to pre-adult with each of the three algal diets.Biometrical differences between Artemia fed the marine algae and that fed Euglena were not consistent in the post-larval stage, but became considerable in the pre-adult stage. Artemia fed with Euglena achieved twice the weight of animals fed the marine algae and showed thehighest length. The implications for the use of on-grown Artemia as afeed in larviculture of marine and freshwater fish and crustaceans are considered.     

Zooplankton capture by a coral reef fish: an adaptive response to evasive prey

Synopsis High-speed cinematography and video using modified Schlieren optics and laser illumination helped elicit details of prey capture mechanisms used by Chromis viridis while feeding on calanoid copepods and Artemia. Chromis viridis is capable of a ram-jaw, low-suction feeding, as well as a typical suction feeding behavior described for other species of planktivores. By adjusting the degree of jaw protrusion and amount of suction used during a feeding strike, this fish can modulate its feeding strikes according to the prey type being encountered. The ram-jaw feeding mode enables C. viridis to capture highly evasive calanoid copepods within 6 to 10 msec. The use of specialized feeding behavior for evasive prey and the ability to vary feeding behavior are adaptations for feeding on evasive prey.     

Prey-related odor preference of the predatory mites Typhlodromalus manihoti and Typhlodromalus aripo (Acari: Phytoseiidae)

Typhlodromalus manihoti and Typhlodromalus aripo are exotic predators of the cassava green mite Mononychellus tanajoa in Africa. In an earlier paper, we showed that the two predators were attracted to odors from M. tanajoa-infested cassava leaves. In addition to the key prey species, M. tanajoa, two alternative prey mite species, Oligonychus ossypii and Tetranychus urticae also occur in the cassava agroecosystem. Here, we used a Y-tube olfactometer to determine the attraction of the predators to odors from O. gossypii- or T. urticae-infested cassava leaves and their prey-related odor preference. T. aripo but not T. manihoti was slightly attracted to odors from O. gossypii-infested leaves. Both predator species showed a stronger response to odors from cassava leaves infested by M. tanajoa over odors from cassava leaves infested by O. gossypii. Neither predator species was attracted to odors from T. urticae-infested leaves and the predators preferred the odors from M. tanajoa-infested leaves over those from T. urticae-infested leaves. When O. gossypii was present together with M. tanajoa on the same leaves or on different sets of leaves offered together as an odor source the two predators were attracted. In contrast, after mixing non-attractive odors from T. urticae-infested leaves with attractive odors from M. tanajoa-infested leaves, neither T. aripo nor T. manihoti was attracted. Ecological advantages and disadvantages of the predators’ behavior and possible implications for biological control of M. tanajoa are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

不同营养模式下内蒙古沙漠小型盐湖卤虫种群特征与环境负载力

通过对桑根达莱淖尔卤虫的养殖实验与卵囊解剖,研究了内蒙古沙漠小型盐湖投饵、施肥与自然状态3种营养模式下卤虫的生境、种群动态、生殖特征,分析了环境对卤虫资源的负载力。结果表明:1在起始种群相同的情况下,不同营养模式对种群结构与密度有显著影响;2不同营养模式对个体生长速度影响存在差异,投饵对加快个体生长速度效果最明显,但在性成熟速度方面不同营养模式没有出现统计学显著差异;3不同营养模式对卤虫的怀卵量、卵生/卵胎生比例有显著影响;与空白组相比,投饵组平均怀卵量提高了35.52%—72.71%,施肥组提高了11.34%—26.15%;4卤虫资源的环境负载力为0.3—0.4 kg/m3,加以补充肥料,可提高到0.45 kg/m3,在投喂饲料的情况下可以达到0.5 kg/m3;5卤虫蛋白可开发量按环境负载力的1/3估计,对照组、施肥组和投饵组的相应年开发量分别为2.61—2.98 kg/m3、4.5—5.4 kg/m3和7.51—8.67 kg/m3,滞育卵产量分别为0.73、1.10 g/m3和1.17 g/m3。     

Natural vitamin E enrichment of Artemia salina fed freshwater and marine microalgae

Three species of microalga, the freshwater Euglena gracilis and the marine Dunaliella salina and Tetraselmis suecica, were compared in terms of vitamin E enrichment and survival and growth of the brine shrimp Artemia salina. The tocopherol content was investigated using HPLC for the post-larval and pre-adult stages of Artemia fed the microalgae and the results compared to the initial content of unfed newly hatched nauplii. There was a markedly higher content of tocopherols (about two-fold) in Artemia fed Euglena. Since this microalga contains other antioxidants such as -carotene, vitamin C and glutathione, bioactive molecules such as PUFA, and the immunostimulant polysaccharide -glucan, it represents a valuable alternative for enriching the diets of Artemia and increase its nutritional value as a food item.     

Characterization of brine shrimp Artemia from Cam Ranh Bay in Central Vietnam

Artemia cysts collected from inoculation experiments in Cam Ranh salterns are evaluated for their potential use in aquaculture. Cyst biometrics, hatching quality, naupliar fatty acid profile and naupliar growth were measured and compared to reference Artemia strains. Cyst characteristics reveal that the parthenogenetic strain (PR China) used in inoculations, was eliminated from the environment and that the remaining brine shrimp are likely to be composed of Macau and Great Salt Lake Artemia strains, and of their cross-breds. Differences in cyst diapause deactivation characteristics between Macau and Great Salt Lake Artemia may have resulted in the disappearance of Macau Artemia during the rainy season and the persistence of Great Salt Lake Artemia during the following dry season.     

Solar Pond devices: free energy or bioreactors for<Emphasis Type="Italic"> Artemia</Emphasis> biomass production?

The recent exponential growth in industrial aquaculture has led to a huge increase in Artemia biomass production in order to meet increased fish production needs. The present study explores the potential use of salt gradient solar ponds (SGSPs) for production of Artemia nauplii. An SGSP is a basin of water where solar energy is trapped and collected via an artificially imposed gradient. Three zones can be identified in an SGSP: upper and lower zones, which are both convective, and a middle zone, which is intended to be non-convective. The latter acts as a transparent insulation layer and allows for storage of solar energy at the bottom, where it is available for use. The combination of salt, temperature and high transparency could make SGSPs promising bioreactors for the production of Artemia nauplii. Using particle image velocymetry (PIV) and Shadowgraph visualisation techniques, the behaviour of Artemia nauplii under critical cultivation parameters (namely, salinity, temperature and light) was monitored to determine movement velocity, and how movement of Artemia affects the salt gradient. It was observed that Artemia nauplii constantly follow light, irrespective of adverse salinity and/or temperature conditions. However, despite the substantial displacement of Artemia following the light source, the salt gradient is not disrupted. The suitability of SGSPs as bioreactors for Artemia biomass production was then tested. The results were disappointing, probably due to the lack of sufficient O₂ for Artemia survival and growth. Follow-up trials were conducted aimed at using the SGSP as a green and economically attractive energy source to induce faster hatching of cysts and improved Artemia nauplii growth. The results of these trials, and a case study of Artemia nauplii production using an SGSP, are presented. The authors constructed a Solar Pond device, which they suggest as a novel way of supplying thermal energy for Artemia biomass production in an aquaculture enterprise. Finally, the authors suggest a method of producing and collecting Artemia biomass, and of heating a fish larval tank, in an ‘ideal’ Solar Pond device, profiting from the low investment costs of using a decommissioned salt works.     

Zooplankton distribution in four ponds of different salinity: a seasonal study in the solar salterns of Sfax (Tunisia)

The seasonal distribution of metazooplankton and large-sized ciliates was studied in four ponds of different salinity in the solar salterns of Sfax (Tunisia). Total zooplankton abundance varied from 1 × 10³ to 4.7 × 10⁶ ind m^–3. Salinity had a negative effect on the abundance of copepods and rotifers which were absent in the pond with the highest salt concentration (180) in which the number of taxa was low and Artemia or the ciliate Fabrea largely dominated the zooplankton community. Temperature and the presence of Dunaliella salina as prey appeared as key factors in controlling the abundance of Artemia, while organic detritus appeared as important in the diet of Fabrea. Change in zooplankton species composition along the hypersaline gradient (40–90) was primarily related to salinity. However, our data suggest the importance of both the abundance and composition of food in the spatial and temporal variations of some zooplankton species.     

Springtail postmolt vulnerability to pseudoscorpion predation: Mechanisms and implications

Arthropod prey are expected to be more vulnerable to their predators immediately following molt. The effects of springtail (Isotoma carpenteri) postmolt vulnerability on interactions with a pseudoscorpion predator were examined in the laboratory. Springtails exposed to vials pretreated with pseudoscorpions (Apochthonius minimus) delayed molting compared to those prey that were exposed to vials pretreated only with springtails. Although their escape ability (measured as distance jumped) was unaffected by molt condition, postmolt springtails were more profitable in terms of reduced predator handling time following capture. Despite this,A. minimus did not distinguish between postmolt and intermolt prey presented at either end of a T-maze.     

Food and feeding of Aurelia aurita in Tokyo Bay with an analysis of stomach contents and a measurement of digestion times

In situ seasonal variations in stomach contents of Aurelia aurita (L.) in Tokyo Bay, Japan, were analyzed. Copepods, such as Oithona davisae Ferrari & Orsi were the predominant food items of A. aurita from June to November. The mean digestion time measured in incubation experiments was 0.95 h. Daily rations calculated using stomach content data and digestion times were 2.2–21.8 mg C ind^–1 corresponding to 0.58–5.56% of body carbon. The ingestion rate increased significantly with an increase in medusa size, although no significant relationship was found between medusa size and carbon specific daily ration. The zooplankton community in Tokyo Bay is characterized by the significant dominance of O. davisae and it is assumed that the prosperity of A. aurita is caused by the high abundance of the O. davisae population. It is suggested that a food chain comprised of microflagellates, cyclopoid copepods O. davisae, and A. aurita is the most significant one in Tokyo Bay and only a small portion of production is transferred to fish.     

Macrolophus caliginosus: Functional response to whiteflies and preference and switching capacity between whiteflies and spider mites

Laboratory experiments were performed with adult female Macrolophus caliginosus Wagner (Heteroptera: Miridae) at 22ºC on bean plants to determine the functional response towards whiteflies, as well as the preference and switching capacity between the two prey species: whiteflies and spider mites. Predation of females presented with first instars of Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodidae) was of a Type III functional response. The observed maximum predation was approximately 75 first instars at high prey densities within a 24-h period. The preference of M. caliginosus females between eggs of T. vaporariorum and Tetranychus urticaeKoch (Acarina: Tetranychidae) changed with the ratio of offered prey. The preference for T. vaporariorum eggs increased non-linearly with increasing proportions of this prey type. The average maximum predation of whitefly and spider mite eggs were approximately 166 and 111 eggs per day, respectively, at the highest ratio of the two preys. The proportion of M. caliginosus females found on the test plants at the end of the experiment increased with prey density suggesting that this mirid spends more time in areas with high prey density. Macrolophus caliginosus females are voracious predators of eggs and first instars of T. vaporariorum as well as of spider mite eggs and may thus be a valuable addition to existing methods of biological control of T. vaporariorum and T. urticae.     

Ontogenetic changes in the ecological function of the association behavior between jack mackerel <Emphasis Type="Italic">Trachurus japonicus</Emphasis> and jellyfish

Commensal behavior of jack mackerel Trachurus japonicus (Temminck & Schlegel) with jellyfishes has been widely observed but its ecological function is still unclear. The goal of the present research is to examine the function of association behavior with jellyfish in the laboratory and in field observations with an emphasis on ontogenetic changes. In the laboratory, jack mackerel juveniles (mean standard length (SL) = 11, 19, 38, and 55 mm) were placed in 500-l polycarbonate tanks with two live moon jellyfish, Aurelia aurita (Linné), and one artificial jellyfish made of silicon. Association behavior with either live or artificial jellyfish was visually observed under the following conditions: control, presence of a predator model, before and after feeding live Artemia, 1 h and 3 h after feeding, and at night. Jack mackerel at 11 mm SL associated with both the moon jellyfish and artificial jellyfish, unrelated to the presence of a predator model or feeding. Juveniles at 19 mm associated with moon jellyfish only in the presence of a predator model. Larger juveniles associated with moon jellyfish at 1 h and 3 h after feeding. Thus the ecological function of association was proposed to develop first from school formation, next as a hiding place from predators, and then as a food source. Underwater observations of jack mackerel associating with giant jellyfish Nemopilema nomurai (Kishinouye) in two different areas in the Sea of Japan supported this hypothesis. High predation pressure from benthic piscivorous fishes in the southern area (Tsushima) may encourage association with jellyfish, whereas pressure from pelagic predators in the northern area (Maizuru) may encourage settlement to rocky reef habitats in temperate waters. Thus the jellyfish may also function as a vehicle for the northward migration of this species. Guest editors: K. A. Pitt & J. E. Purcell Jellyfish Blooms: Causes, Consequences, and Recent Advances     

Prey Preference by the StinkbugPerillus bioculatus,a Predator of the Colorado Potato Beetle

Perillus bioculatus(F.) is sometimes considered a generalist but has most often been recorded as predator of Colorado potato beetle (CPB),Leptinotarsa decemlineata.(Say). This study was designed to analyze prey selection inP. bioculatuswith respect to factors that may lead to specialization. To establish if parental prey determines preference in na?&#x0308;ve progeny, prey selection experiments were conducted with the CPB and two unusual prey, the yellow mealwormTenebrio molitor(L.) and the house cricketAcheta domesticus(L.). Na?&#x0308;ve nymphs reared from yellow mealworm-fed parents in the absence of contact with the CPB initiated feeding more frequently on CPB (81.4%) than on cricket prey (69.6%) (P = 0.038), suggesting genetically inheritable preference for CPB. Progeny from CPBfed parents initiated feeding more frequently on CPB prey (93.3%) than on yellow mealworm prey (76.6%) (P = 0.0001), but progeny from yellow mealwormfed parents initiated feeding on yellow mealworm prey as frequently (89.2%) as on CPB (95.0%) (P = 0.613). Similarly, progeny from CPB-fed parents established proboscis contact more frequently on CPB (39.2%) than on house cricket prey (25.0%) (P = 0.008), whereas those from cricket-fed parents probed house cricket prey as frequently (12.5%) as CPB prey (15.4%) (P = 0.416). Results confirm specialization ofP. bioculatustoward CPB or related prey and suggest genetically inheritable as well as maternally reinforcible affinity toward CPB prey. However, affinity of na?&#x0308;ve nymphs for the CPB can be lowered by rearing parents on alternative prey, increasing their chances of survival when alternative prey must be relied upon.     

Hydrocarbon-released nestmate aggression in the Argentine ant, Linepithema humile, following encounters with insect prey

Argentine ants, Linepithema humile, were attacked by their nestmates following contact with a particular prey item, the brown-banded cockroach, Supella longipalpa. Contact with prey, as brief as 2 min, provoked nestmate aggression. Argentine ants contaminated with hydrocarbons extracted from S. longipalpa also released nestmate aggression behavior similar to that released by the whole prey item, confirming the involvement of hydrocarbons. In contrast to S. longipalpa, little or no nestmate aggression was induced by other ant prey from diverse taxa. A comparison of prey hydrocarbon profiles revealed that all hydrocarbons of S. longipalpa were very long chain components with 33 or more carbons, while other prey had either less, or none, of the very long chain hydrocarbons of 33 carbons or greater. We identified the hydrocarbons of S. longipalpa and some new groups of long chain hydrocarbons of L. humile. The majority of S. longipalpa hydrocarbons were 35 and 37 carbons in length with one to three methyl branches, and closely resembled two previously unidentified groups of compounds from L. humile of similar chain length. The hydrocarbons of S. longipalpa and L. humile were compared and their role in the Argentine ant nestmate recognition is discussed.     

Morphology and defensive structures in the predator-prey interaction: an experimental study of Parabroteas sarsi (Copepoda,Calanoida) with different cladoceran prey

Parabroteas sarsi is a predaceous calanoid copepod commonly found in South Andes lakes. Feeding experiments were carried out in order to estimate the predation rates and attack patterns on different cladoceran prey. Predation rates were related with prey sizes. The smallest prey, Bosmina longirostris, was ingested up to 5 prey pred^–1 h^–1 while the largest, Daphnia middendorffiana, only at 0.12 prey pred^–1 h^–1. The functional response of P. sarsi differed when confronted with different prey although in all cases, the number of kills increased with prey density. A saturation of ingestion rates at high prey densities was only observed for B. longirostris and Ceriodaphnia dubia juveniles. Remains seldom appeared at the end of the experiments, implying that the predator consumed prey totally. Yet, in all experiments carried out with Daphnia ambigua and D. middendorffiana, remains, including soft parts, were found. Direct observations of attack and of number and types of remains showed interference of handling by tail, helmet, and size of the prey.     

Occurrence of an alternative pathway in the larval development of the crab Chasmagnathus granulata Dana, 1851 under laboratory conditions

Larvae of the crab Chasmagnathus granulata were collected in a salt marsh located in the Lagoa dos Patos, Brazil and reared from eclosion to metamorphosis under different dietary regimes. Larvae reared individually in beakers of 40 ml and fed Tetraselmis chuii (zoea III and zoea IV), showed a supplementary stage, here designated as zoea V, with morphological characteristics intermediary between zoea IV and megalopa. No zoeae V molted to megalopa stage. To confirm the occurrence of the supplementary stage, mass cultures of larvae of C. granulata were fed Artemia sp. at high densities, we again detected the fifth zoeal instar. However, when zoeae V were individually placed in beakers and fed Artemia nauplii, they succeeded in molting into megalopae. We observed the occurrence of two types of zoeae IV — a smaller type (from which originated the zoeae V) and a larger type (which directly developed into megalopae). We conclude that stressful nutritional/environmental conditions were responsible for the occurrence of this alternative path of development.     

Functional responses of five cyprinid species to planktonic prey

Synopsis The functional responses of five species of cyprinids (Chalcalburnus chalcoides, Vimba vimba, Abramis brama, Rutilus rutilus, and Scardinius erythrophthalmus) feeding on four planktonic prey types were measured in the laboratory. Although no alternative prey types were present, the response curves were sigmoid in most cases, because attack rates were not independent of prey density. The findings are explained as being the overt expression of the fishes& foraging tactics. The chief way of maximizing food uptake, according to our interpretation, is accelerating attack rates with increasing prey density. The ability of prey to escape or relative prey size may interfere with this strategy. C. chalcoides, the only obligatory planktivore among the species studied, attacks at higher rates and responds most markedly to changes in prey density.     

Craniometrical variations among eastern Brazilian marmosets and their systematic relationships

The craniometrical variations among marmosets on the eastern coast of Brazil or theCallithrix jacchus group (C. jacchus, C. penicillata, C. kuhli, C. geoffroyi, C. flaviceps, andC. aurita) were analyzed to test various hypotheses for the arrangement of the species and phylogenetic relationships ofC. kuhli andC. flaviceps. Q-mode correlation coefficients and principal component analysis were employed to extract important shape factors from the craniometrical data. On this basis, the shape distances among the eastern Brazilian marmosets were found to be larger than those between the marmosets which are recognized as distinct species. This evidence supports the hypothesis that the members of theC. jacchus group are distinct species.C. kuhli shows the strongest resemblance toC. geoffroyi within theC. jacchus group.C. flaviceps is the most similar toC. aurita in its cranial shape. These findings indicate thatC. kuhli is most closely related toC. geoffroyi, whileC. flaviceps is toC. aurita.