The evaluation of the effects of early starvation and feeding on survival and growth in the early stages of the life cycle of ornamental marine caridean shrimp species is fundamental to establish adequate feeding protocols in their culture. In this study, we determine the nutritional vulnerability in the early larval stages of ornamental shrimp Lysmata ankeri exposed to different periods of starvation or feeding. The larvae were separated into three groups (zoea I-ZI, zoea II with ZI fed, and zoea II with ZI unfed) and subjected to two experiments: (1) point-of-no-return (PNR), comprising one or two days of initial starvation followed by feeding; and (2) point-of-reserve-saturation (PRS), comprising one or two days of initial feeding followed by starvation. Each experiment was still composed of two control groups: continuous feeding and continuous starvation. Larvae tolerated some periods of starvation, with a high PNR value (2.00) and low PRS (0.50). Longer periods of starvation influenced both growth and survival rates in zoea II stages. The nutritional vulnerability index for zoea I was 0.25, which represents a low dependence on food supply. In this study, it was observed that ornamental shrimp L. ankeri larvae hatch with energy reserves, presenting facultative primary lecithotrophy, in which they are able to moult from zoea I to zoea II using such reserves in the absence of food. In this sense, the early larvae stages (zoeas I and II) can tolerate a certain period of starvation, indicating the great potential of this species for aquaculture.

Studies on the larval development of fish are essential for conservation and improvements in cultivation techniques. Geophagus brasiliensis popularly known as Cará has potential as a fish of interest in ornamental aquaculture. Wild adults of G. brasiliensis were kept in an aquarium for spontaneous reproduction. Newly hatched larvae were transferred to 5-litre aquaria at 22, 26 and 30°C until total yolk sac resorption. Histological slides were used for biometric analysis and monitoring of larval ontogenesis at different temperatures. Histologically, from the first to the fourth days it was possible to identify myomeres, optic vesicle, yolk syncytial layer, brain, heart and differentiation of the eye layers. From the fourth to the seventh days, it was possible to identify mandibular and gill cartilages, swim bladder, liver, prismatic epithelium with striated border in intestine and renal epithelium. All biometric measurements increased over the days, except height and length of the yolk sac, which gradually decreased until the complete resorption of the yolk sac that occurred on the fifth day at a temperature of 30°C, the sixth day at 26°C and the seventh day at 22°C. Morphological events at 30°C such as the reabsorption of the yolk sac, the appearance of cartilage in the branchial arches and differentiation of the layers of the eyes occurred faster compared with the other temperatures tested. Opening of the mouth and digestive tract occurred at a similar time on the fourth day in all temperatures.

The first zoeal stages of the snapping shrimps Alpheus carlae and A. intrinsecus from Brazil were obtained from laboratory-hatched specimens and a detailed morphological description is provided. The morphological characteristics of both species are compared with available descriptions of other Alpheus species with a known first zoeal stage. Remarks from a semi-quantitative comparison of species belonging to A. armillatus species complex (A. carlae and A. brasileiro) and a comparison between larvae of A. intrinsecus from two localities in Brazil are presented. It was possible to distinguish first zoea of both species from the other congeners based on morphology. No intraspecific variability was detected between A. intrinsecus larvae obtained from two locations. Some structures showed differences between species of the A. armillatus complex. However, generalizations and conclusions based on larval morphology for taxonomic rearrangements at this point need to be made with caution and accuracy, since data of a sufficient number of species are not yet available for comparison.

Lysmata vittata is considered an invasive shrimp in the Atlantic Ocean and some characteristics might have contributed to its invasive success, such as its larval nutritional vulnerability during the early stages of development. The objective of this study was to evaluate the early larval stages of the shrimp L. vittata. Ovigerous specimens were captured in an estuarine region of north-eastern Brazil. Zoeae were assigned to two experiments: (1) the point of no return (PNR), consisting of treatments with an increasing number of days of starvation and subsequent days of feeding; and (2) the point of reserve saturation (PRS), consisting of treatments with an increasing number of days of feeding and subsequent days of starvation. Two control groups were considered: continuous starvation (CS) and continuous feeding (CF). Nutritional vulnerability was estimated by the time when 50% of the initially starved larvae (PNR50) lost the ability to moult to the next stage, when 50% of the initially fed larvae (PRS50) were capable of moulting to the next stage. In the CF, the mean development time (±SD) of the larvae that reached stage III was 4.36 ± 0.74 days with a mortality of 70%, and the mean carapace length (±SD) was 0.61 ± 0.04 mm CL. The PNR50 and PRS50 were 2.42 ± 0.14 and 1.32 ± 0.83 days, respectively. The nutritional vulnerability index (PRS50/PNR50 = 0.54) indicates that L. vittata presents intermediate dependence on exogenous food during the early larval stages, which might help our understanding of the invasive potential of this species in the Atlantic Ocean.

The morphology of the zoeal stages IX and XI of the shrimp Thalassocaris lucida is described and illustrated in detail from plankton specimens identified by barcoding of the mitochondrial 16S ribosomal RNA gene (sequence similarities 99.4–99.6%). The present study confirms the larval morphology of Thalassocaris, that shows distinct features within Pandaloidea: (1) carapace broad and dorsoventrally flattened, (2) coxal endite of maxilla with only one lobe, (3) basis of third maxilliped with a distal globose lobe. On the other hand, the funnel-shaped eyes, and the development with long series of larval stages of Thalassocaris indicate affinities with some genera of Pandalidae which corroborates the results of recent phylogenetic analyses in abandoning the family status of Thalassocarididae.

Toxocara canis (Werner, 1782) is a zoonotic nematode commonly parasitizing dogs worldwide with great public health importance as the aetiological agent of human toxocariasis. In this respect, the aim of this study was to evaluate the effect of six disinfectant products commonly used in kennels, veterinary clinics and as household cleaning products on the embryogenesis and viability of T. canis eggs. The composition of active ingredients in these commercial disinfectants was sodium hypochlorite (A); a mix of N-(3-aminopropyl)-N-dodecylpropan-1.3-diamine and didecyldimethylammonium chloride (B); sodium dichloroisocyanurate dehydrate (C); a mix of glutaraldehyde, quaternary ammonium compounds, benzyl-c12-18-alkyldimethyl and chlorides (D); a mix of 2-propanol, ethanol, benzalkonium chloride and glucoprotamin (E); a mix of pentapotassium bis (peroxymonosulphate) bis (sulphate), sodium C10-13-alkylbenzenesulphonate, malic acid, sulphamidic acid, sodium toluenesulphonate, dipotassium peroxodisulphate and dipentene (F). After dilution, the tested disinfectants had the maximal concentration recommended by the manufacturer in order to achieve a biocidal effect. Each product was tested on approximately 10,000 T. canis eggs, having five different contact times (5, 10, 15, 30, 60 min). Three replicates were tested for each diluted disinfectant and for each contact time. After the treatment, eggs were washed and incubated in distilled water at 27 °C for 2 weeks. None of the tested products had a significant inhibitory effect on the embryogenesis and viability of T. canis eggs, regardless of the contact time. Moreover, after 2 weeks, in all tested samples, eggs containing motile infective larvae were identified, showing that routinely used disinfectants do not eliminate risk of infection by T. canis.

Caobangiids are an aberrant group of annelids with an unusual phoronid-like body plan. The most perceptible anatomical characteristic of caobangiids is the anal trunk, which is recurved outside the body and ends with an anal opening located near the head. So far neither the larval development nor the metamorphosis of these worms have been investigated thoroughly. This study describes the larval development and metamorphosis of Caobangia billeti, and focuses mainly on the formation of the alimentary tract. The trochophore has eight chaetigers. Embryogenesis includes the development of segmentally arranged bands of cilia and ventral ciliary fields, the development of chaetae and the early formation of anterior radioles. Upon exiting the larval duct, larvae have eyes with lenses, two pairs of rudimentary radioles on the prostomium, a pair of nephridia on the peristomium, and two capillary chaetae in each parapodium of segments 3–9; parapodia of the 10th segment also bear a row of palmate hooks. Metamorphosis takes about 20 h and involves dorso-ventral folding of the body and enlargement of the pygidium along the dorsal side of segments 5–8. Thus, the anus develops on the dorsal side of the 5th segment, the anal trunk forms from the projection of pygidium whereas the prepygidial growth zone appears posterior to the 8th body segment. After the completion of metamorphosis, the prostomial and peristomial segments are fused and reduced, eight full thoracic chaetigers derive from the larva's body. Abdominal chaetigers grow posteriorly from the prepygidial growth zone.

The present study describes the morphological changes of the mouthparts and foregut of the freshwater prawn M. acanthurus that occur during the development of the larvae and first juvenile. The results indicate that the zoeae I have mouthparts with reduced setae and a structureless foregut that indicates obligatory lecithotrophic behaviour. There is an increase in the number of setae in these structures between the zoea II and the juvenile stage, indicating the adaptation of the organism for feeding. More complex structural alterations were observed in the first juvenile, which acquires benthonic habits, which ensure the capture and ingestion of a diversity of feeding resources found in the substrate.

Aelurostrongylus abstrusus is a worldwide occurring lungworm affecting felids. This metastrongyloid nematode has an indirect lifecycle relying on slugs and snails as intermediate hosts. In the present study the development of first-stage (L1) to third-stage larvae (L3) in the tropical freshwater pulmonate snail Biomphalaria glabrata was assessed. A total of 306 snails were individually exposed to 300 A. abstrusus L1, which were obtained from a naturally infected stray cat. The species was confirmed by biomolecular analysis. Second stage larvae (L2) and L3 were first isolated by artificial digestion of snails in the second and fourth week post exposure (wpe), respectively. From 8 wpe onwards, all larvae had developed into L3. Snails remained infected for up to 26 wpe. Only 0.4% of the L1 had pursued their development into L3, indicating low suitability of this artificial intermediate host for production of infective A. abstrusus L3.

Two new species of South African Syllidae of the genus Syllis Lamarck, 1818 are described. Syllis unzima sp. nov. is characterized by having unidentate compound chaetae with long spines on margin, a characteristic colour pattern and its reproduction by vivipary. Vivipary is not common among the polychaetes, but most representatives occur in the family Syllidae Grube, 1850 (in five other Syllis species, two species of Dentatisyllis Perkins, 1981 and two species of Parexogone Mesnil & Caullery, 1818). Syllis unzima sp. nov. differs from the other viviparous species in having large broods (>44 juveniles) which develop synchronously. Development of the juveniles is similar to that of free-spawning Syllis species, but the appearance of the first pair of eyespots and the differentiation of the pharynx and proventricle occur later in S. unzima. Syllis amicarmillaris sp. nov., is characterized by having an elongated body with relatively short, fusiform dorsal cirri and the presence of one or two pseudosimple chaeta on midbody parapodia by loss of blade and enlargement of shaft. Syllis unzima sp. nov. was found in high densities on cultured Holothuria scabra Jaeger, 1833 with single specimens found on a cultured Crassostrea gigas Thunberg, 1793 and on coralline algae, respectively, while S. amicarmillaris was found mainly in sediment outside an abalone farm and less frequently on cultured Haliotis midae Linnaeus, 1758. We discuss the possible benefits of the association with H. scabra to S. unzima sp. nov.

The aim of this project was to evaluate the impact of probiotic (Phaeobacter gallaeciensis, X34 strain) treatment on the complete development (from veliger to metamorphosis) of Pecten maximus larvae in the context of a bacterial challenge and in conditions more representative of hatchery practices. To that effect, the present study was divided into two main steps. In the first, we used in vitro analyses (antibiograms and microplate assays) to validate the inhibition abilities of X34 on the growth of four Vibrio pathogen species. During the second step, we added pathogens (Vibrio pectenicida) into rearing tanks after two weeks of pre-treatment with the probiotic and then followed the larval development of Pecten maximus through the monitoring of survival rates, shell lengths and metamorphosis ability. Moreover, antioxidant (catalase and superoxide dismutase) and lipids peroxidation activities were also measured after bacterial challenge in order to evaluate the physiological response of larvae to pathogen exposition. Our results indicated an activation of the two selected antioxidant enzymes after bacterial challenge, but the increase was significantly lower in probiotic treated larvae. At the end of the experiment, the strain X34 treatment prevented a mass mortality event and showed a significant increase in the number of individuals reaching competence, when compared to untreated larvae.

Aelurostrongylus abstrusus (Strongylida, Angiostrongylidae) and Troglostrongylus brevior (Strongylida, Crenosomatidae) are regarded as important lungworm species of domestic felids, with the latter considered an emerging threat in the Mediterranean region. The present study aimed to assess their concurrent development in the mollusc Helix aspersa (Pulmonata, Helicidae). Thirty snails were infested with 100 first-stage larvae (L1) of A. abstrusus and T. brevior, isolated from a naturally infested kitten. Larval development was checked by digesting five specimens at 2, 6 and 11 days post infestation. Larvae retrieved were morphologically described and their identification was confirmed by specific PCR and sequencing. All H. aspersa snails were positive for A. abstrusus and T. brevior, whose larval stages were simultaneously detected at each time point. In addition, snails were exposed to outdoor conditions and examined after overwintering, testing positive up to 120 days post infestation. Data herein presented suggest that A. abstrusus and T. brevior develop in H. aspersa snails and may eventually co-infest cats. Data on the morphology of both parasitic species in H. aspersa provide additional information on their development and identification, to better understand the population dynamics of these lungworms in receptive snails and paratenic hosts.

With the advent of transgenic Bacillus thuringiensis (Bt)-cowpea, there is a need to identify the feeding preferences of Maruca vitrata Fab. to determine in which component of the plant the expression of the toxin needs to be the highest to ensure the greatest efficacy of insecticidal Bt proteins. In the current study, we examined the feeding preferences of M. vitrata larvae in a naturally infested cowpea field. We also tested, in the laboratory, the suitability of different flower components for the larval development of M. vitrata. Our results indicate that in the field, all types of flowers, regardless of their age, were infested with M. vitrata larvae. The reproductive organs, in the flowers, were the preferred feeding diet for the larvae. Laboratory bioassays confirmed that the reproductive organs were the optimal tissues for M. vitrata larval development. The implications of these findings for transgenic Bt-cowpea are discussed.

Climate change in the Arctic is anticipated to alter the ecology of northern ecosystems, including the transmission dynamics of many parasite species. One parasite of concern is Ostertagia gruehneri, an abomasal nematode of Rangifer ssp. that causes reduced food intake, weight loss, and decreased pregnancy rates in reindeer. We investigated the development, availability, and overwinter survival of the free-living stages of O. gruehneri on the tundra. Fecal plots containing O. gruehneri eggs were established in the Northwest Territories, Canada under natural and artificially warmed conditions and sampled throughout the growing season of 2008 and the spring of 2009. Infective L3 were present 3–4 weeks post-establishment from all trials under both treatments, except for the trial established 4 July 2008 under warmed conditions wherein the first L3 was recovered 7 weeks post-establishment. These plots were exposed to significantly more time above 30°C than the natural plots established on the same date, suggesting a maximum temperature threshold for development. There was high overwinter survival of L2 and L3 across treatments and overwintering L2 appeared to develop to L3 the following spring. The impact of climate change on O. gruehneri is expected to be dynamic throughout the year with extreme maximum temperatures negatively impacting development rates.

Upogebia vasquezi inhabits the western Atlantic in the regions of southern Florida, the Bahamas, Central America and Brazil (from the States of Maranhão to São Paulo). Its occurrence has been extended to the coastal region of the State of Pará (northern Brazil). There are few descriptions of the larval development of the 116 known species of Upogebia. The present study offers the first description and illustrations of the first two larval stages (zoeas I and II) of U. vasquezi reared in laboratory. The larval features of U. vasquezi were compared with those of two other species of Upogebia, revealing very similar morphological characteristics among species in zoea I. The main variation in this larval stage was in the segmentation of the maxillulary endopod. In zoea II, the number of setae on the scaphognathite was different among some species of Upogebia. The present study contributes to the available literature on the identification of thalassinidean larvae.

Entedon erythrinae sp. n. (Hymenoptera: Eulophidae), a gregarious egg-larval endoparasitoid of the Erythrina bruchine Specularius impressithorax, an invasive pest of the coral tree seeds (Erythrina spp.), is described from the Hawaiian Islands and Africa (South Africa, Tanzania and Mozambique). The biology and morphology of preimaginal stages of this new species are described in details.

It is remarkable that the early embryo of the parasitoid represents a mass of undifferentiated cells surrounded by a peculiar membrane formed by the peripheral enlarged polygonal cells. The young larva developing inside this membrane corresponds morphologically to the second instar of congeneric species. Various peculiarities of the parasitoid-host relationships in gregarious and solitary Entedon parasitoids are discussed. The DNA sequences of 28S D2 (nuclear), Cytochrome Oxidase I (COI, mitochondrial) and Cytochrome B (CytB, mitochondrial) genes are provided for this new species and compared with the sequences of some other Afrotropical and Palearctic species of the genus.

Acute toxicity of ammonia was investigated in four life stages of juvenile chub, Leuciscus cephalus (cyprinid fish): 1, 10, 20 and 30 days after the first feeding. The fish used for the toxicity test were reared intensively in a closed recirculation system. Each acute toxicity test duration was 96 h and lethal concentration LC1, LC50 and LC99 values were calculated for 24, 48, 72 and 96 h. The susceptibility of chub to acute ammonia toxicity decreased linearly with age and stage of development. The LC50 (48 h) values ranged from 0.62 mg L-1 of unionized ammonia nitrogen for one day after first feeding larvae to 1.73 mg L-1 for 30 days after first feeding ones. A significant linear relationship between chub larvae susceptibility to ammonia toxicity and both body weight and length was found. The critical level of unionized ammonia nitrogen for chub larvae was suggested as 0.49 mg L-1.

Metaphycus flavus (Howard) (Hymenoptera: Encyrtidae) is a facultatively gregarious endoparasitoid of soft scales (Hemiptera: Coccidae). When it develops in superparasitised hosts, the larvae often attack and consume brood mates six or more days post oviposition. Under our laboratory conditions (25±1°C and 14 hours of light followed by 18±1°C and ten hours of darkness in 50–70% R.H.), M. flavus eggs hatched three days after oviposition. Measurements of the mandibles and tentorium indicate there are four larval instars, and M. flavus reaches the fourth instar by day six post oviposition, and pupates on day eight. Thus, cannibalism among M. flavus larvae occurs during the fourth instar. During this instar, M. flavus larvae separate from their attachment to the scale cuticle, to which they were tethered by a respiratory structure during the previous three larval instars. Once detached, they are free to move within the scale, which increases the probability of larval encounters and aggressive behaviours. Moreover, the mandibles of the fourth instar are better adapted for fighting than are those of the first three larval instars, since they are larger and more sclerotized. The cranium and mouthparts of M. flavus have four different types of sensory organs, some of which are almost certainly olfactory, an unexpected function for a larva that presumably is surrounded by an aqueous medium where gustatory sensilla would seem to be more appropriate. The cranium also bears two pairs of what appear to be secretory pores.

Larvae of Stenorhynchus seticornis were reared in the laboratory in a factorial experiment employing three temperatures (22, 25 and 28°C) and three salinities (30, 35 and 40‰) to determine the effects of these variables on the survival and duration of the larval stages. Larvae from five females were subdivided in six groups of 10 and reared in glass bowls containing 125 ml filtered and UV-irradiated seawater at different temperature–salinity combinations. Larvae were transferred daily to clean bowls with newly hatched Artemia nauplii, and the number of moults and mortality within each bowl was recorded. Complete larval development of S. seticornis occurred under all experimental conditions, except at temperature 28°C and salinity 35‰. Salinity affected percentage survival of the two zoeal stages, but not that of the megalopa. Survival of the second zoeal stage, the megalopa, and the complete development to the first crab was affected by temperature, with the greatest survival occurring at 25°C. Duration of the two zoeal stages, the megalopa, and development to the first crab stage showed a gradual reduction with increasing temperature. Development from hatching to the first crab stage required 17 to 31 days and was inversely related to temperature, averaging 26.9 days at 22°C, 21.0 days at 25°C and 19.7 days at 28°C. Salinity affected the duration of the first zoeal stage only.

Parablennius gattorugine and Parablennius ruber are closely related sympatric western European species. In this note, traits that distinguish the larvae of both species are presented and it is demonstrated that conflicting descriptions reported in the literature on the larvae of P. gattorugine stem from confusion between the two species.