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We evaluated the direct effects of progesterone on the morphology, maturation and behavior of Haemonchus contortus larvae in vitro . The presence and location of possible progesterone receptors in these larvae were also determined. The addition of 8 ng/mL of progesterone to larval cultures over 10 days reduced larval enlargement, while the addition of 160 ng/mL of the hormone increased the enlargement. Up to 62% and 65% of the H. contortus larvae molted from third-stage larvae (L3) to fourth-stage larvae (L4) when cultured in RPMI-1640 media without hormone for 5 and 10 days, respectively. The addition of different progesterone concentrations (1, 8, 16, 80 and 160 ng/mL) to the larval cultures significantly inhibited the molting process within the same periods. The addition of 8 ng/mL or higher progesterone concentrations to the cultures significantly increased larval motility (p < 0.05) compared with unstimulated larvae. Flow cytometry showed the expression of progesterone receptors (P4-R) in 15% of the cells from newly isolated H. contortus larvae. When the larvae were cultured for 5 days in the presence of the hormone, the percentage of P 4 -R+ cells remained the same. In contrast, unstimulated larvae showed a significant reduction in the number of P 4 -R+ cells. Using confocal microscopy, a greater concentration of P 4 -Rs was immunolocated in the anterior portion of the alimentary tract of the larvae, suggesting that the cells in this region are targeted by the hormone. The results of the present study show that H. contortus larvae have possible P 4 -Rs and respond to this hormone by inhibiting their molting process, thereby suggesting the participation of progesterone in the larval arrest phenomenon. [ABSTRACT FROM AUTHOR]

Hatchery production of great scallop, Pecten maximus, remains unpredictable, notably due to poor larval survival. Large-scale flow-through systems up to 3500 L have been developed to avoid the use of antibiotics in static systems. Alternatively, small-scale flow-through systems have been successfully applied for oysters but they proved to be unsuitable to rear scallop larvae. By focusing on physical factors presumed to limit P. maximus larval development, this study aimed to optimize great scallop larvae rearing parameters under controlled conditions. First, the influence of aeration on larval performances, energetic metabolism and antioxidant defences were studied both in static and flow-through systems. Aeration depressed larval food intake, regardless of the intensities of flow tested (100 ml/min, 155 ml/min and 270 ml/min). On the other hand, antioxidant enzyme activities remained constant or decreased, suggesting that antioxidant defences were inactivated. The increase in citrate synthase activity suggested an increase in metabolic rate possibly due to a turbulent stressful environment. All larvae exposed to such turbulence died before reaching metamorphosis, whereas those reared without aeration survived well (≈ 95%). The effects of water renewal were thereafter studied in 50-L flow-through flat-bottomed tanks. No differences in survival (20.4 ± 0.5%), growth (3.8 ± 0.2 μm/d), competence (5.6 ± 0.2%), energetic metabolism level and antioxidant enzyme activities were observed when comparing 12.5 and 25 L/hr water renewal. Whereas air bubbling leads to detrimental effects, flow-through in small flat-bottomed tanks appears to be a suitable technique for scallop larvae rearing. [ABSTRACT FROM AUTHOR]

Under global change organisms are exposed to multiple, potentially interacting stressors. Especially interactions between successive stressors are poorly understood and recently suggested to depend on their timing of exposure. We particularly need studies assessing the impact of exposure to relevant stressors at various life stages and how these interact. We investigated the single and combined impacts of a heat wave (mild [25 °C] and extreme [30 °C]) during the egg stage, followed by successive exposure to esfenvalerate (ESF) and a heat wave during the larval stage in damselflies. Each stressor caused mortality. The egg heat wave and larval ESF exposure had delayed effects on survival, growth and lipid peroxidation (MDA). This resulted in deviations from the prediction that stressors separated by a long time interval would not interact: the egg heat wave modulated the interaction between the stressors in the larval stage. Firstly, ESF caused delayed mortality only in larvae that had been exposed to the extreme egg heat wave and this strongly depended upon the larval heat wave treatment. Secondly, ESF only increased MDA in larvae not exposed to the egg heat wave. We found little support for the prediction that when there is limited time between stressors, synergistic interactions should occur. The intermediate ESF concentration only caused delayed mortality when combined with the larval heat wave, and the lowest ESF concentrations only increased oxidative damage when followed by the mild larval heat wave. Survival selection mitigated the interaction patterns between successive stressors that are individually lethal, and therefore should be included in a predictive framework for the time-scale dependence of the outcome of multistressor studies with pollutants. The egg heat wave shaping the interaction pattern between successive pesticide exposure and a larval heat wave highlights the connectivity between the concepts of ‘heat-induced pesticide sensitivity’ and ‘pesticide-induced heat sensitivity’. [ABSTRACT FROM AUTHOR]

Bacterial infection and heat stress, as two major environmental threats of marine molluscs, could affect larval development and dramatically promote mortality of oysters. In the present study, next-generation sequencing, together with determinations of mRNA expression and measurements of enzyme activities, were employed to understand the response patterns of oyster larvae under acute heat and bacterial stress. After RNA-seq, a total of 9472 differentially expressed genes including 4895 significantly up-regulated ones and 4577 significantly down-regulated ones were obtained from 12 transcriptome libraries. GO overrepresentation analysis of the up-regulated genes revealed that the neuroendocrine immunomodulation pathway was activated after acute heat and bacterial stimulation, in which the catecholaminergic regulation played an important role. GO overrepresentation analysis of the down-regulated genes suggested that the immune capacity of Crassostrea gigas larvae was suppressed under stress, which was further validated since superoxide dismutase (SOD) and phenoloxidase (PO) activities in the total protein extract of larvae decreased dramatically after stress. Moreover, the shell formation of trochophore was inhibited and severe mortality was caused after acute heat and bacterial stress. These results collectively indicated that acute heat and bacterial stress could significantly inhibit larval development and suppress immune response of oyster C. gigas larvae. And the neuroendocrine immunomodulation, especially the catecholaminergic regulation, played an indispensable role in the stress response of molluscan larvae. [ABSTRACT FROM AUTHOR]

The clam, Panopea globosa , is one of two geoduck species intensively exploited in Mexico because of its high demand and commercial export value to Asian countries. Current efforts to develop successful seed production technology involve appropriate methods for improving the survival of larval and metamorphic stages. Several organic and inorganic chemicals have been successfully used to induce, synchronize or accelerate the settlement and/or metamorphosis of different molluscan species. In the present study the effect of 5 chemicals (serotonin, GABA, L -DOPA, epinephrine and KCl) on the metamorphosis of P. globosa larvae was tested at 3 different concentrations (10 − 6 , 10 − 5 and 10 − 4 M, or 1, 10 and 20 mM in the case of KCl), with 3 different exposure periods (1.5, 6 and 24 h). Percent metamorphosis and survival were evaluated after 30 h. In each case, 3 metamorphic phases were documented (initial, intermediate and completed). Survival approached 100% after exposure to the different treatments, except with L -DOPA, where 80% of P. globosa larvae died after 24 h exposure at the highest concentration (10 − 4 M). The compounds GABA, L -DOPA and KCl failed to induce larval metamorphosis when compared to their respective controls. Serotonin rapidly triggered the initiation of metamorphosis, and the highest percent of metamorphosed larvae (87% ± 6.7 standard error) was observed in the combination of 6 h exposure and 10 − 6 M concentration. Epinephrine effects were slower than those of serotonin, yet the former also induced a high percent metamorphosis (> 75%) after 6 to 24 h exposure to a concentration of 10 − 4 M or 10 − 6 M. It is concluded that both serotonin and epinephrine can be potentially used to accelerate and synchronize the process of metamorphosis of P. globosa larvae. [ABSTRACT FROM AUTHOR]

Controlled incorporation of selected microalgae and bacteria in aquaculture systems can be beneficial because they can act as microbiological control. That is why the characteristics of biofilm generated naturally in Seriola lalandi culture cages were analysed, their potential benefit to the growth of larvae was studied, and their controlled use for improving the larval viability and as a vector to improve incorporation of previously studied probiotic bacteria was tested. According to biodiversity results, these biofilms are composed of a diatom-bacteria mix showing a decrease in biodiversity in laboratory culture conditions being dominated by Navicula phyllepta and bacteria of the family Rhodobacteraceae. This can be produced on mesh substrates incorporated in bioreactors with rapid growth rate and adhesiveness. Preliminary results from the addition of substrates with this specific biofilm in larvae culture systems showed that it is consumed by the larvae without negative effects, while positive effects on the viability of larvae in combination with probiotics were observed. Considering preliminary results, the addition of these specific substrates with diatom-bacteria biofilms could be a good improvement for aquaculture systems and together with the use of probiotics can contribute to maintaining a stable and controlled system improving the viability of the larval fish culture in its early stages. [ABSTRACT FROM AUTHOR]

The use of herbal medicines either in combination with or instead of synthetic anthelmintics is an approach to reducing the exposure of parasites to synthetic chemicals. The present study aimed to assess the in vitro and in vivo effects of Spigelia anthelmia decoction (SaDec) on sheep gastrointestinal nematodes. SaDec was obtained by extracting active constituents of the plant in boiling water. The condensed tannins present in SaDec were quantified and subjected to phytochemical analysis. The egg hatch test (EHT), the larval development test (LDT), and an adult worm motility (AWM) assay were performed. Ultrastructural changes in the cuticle of the adult Haemonchus contortus were evaluated by scanning electron microscopy (SEM). Acute toxicity tests in mice were performed to define the safe dose of SaDec to be administered in the fecal egg count reduction test (FECRT) In the FECRT, fecal samples were collected at days 0, 7 and 14 post-treatment to estimate the eggs per gram (epg) and to identify the most prevalent nematode genera. The results of the EHT and LDT were analyzed using analysis of variance (ANOVA) and compared using Tukey’s test ( P < 0.05). The effective concentration to inhibit 50% (EC 50 ) of egg hatching or larval development was determined by the probit method. In the AWM assay, worm survival was analyzed with the non-parametric stratified Cox regression test. The efficacy in the FECRT was calculated using BootStreat 1.0 software. The phytochemical screening detected high concentrations of condensed tannins, flavonoids, flavones, saponins, alkaloids and xanthones. The weights of the total phenolics and the condensed tannins were 96.56 and 51.25 mg gallic acid equivalents (GAE)/g dry weight (DW), respectively. The EC 50 ± 95% confidence interval values of SaDec for the EHT and LDT were 1.4 (1.2–1.6) and 1.2 (1–1.3) mg/ml, respectively. Treatment with SaDec at 1.6 mg/ml produced 100% inhibition of worm motility after 12 h of exposure. SEM revealed ultrastructural changes in the cephalic region and cuticle of H. contortus females. In the acute toxicity test, there was no mortality in mice. SaDec at 350 mg/ml reduced the sheep epg by 47% at 14 days post-treatment. Haemonchus was the most prevalent nematode genus. This study demonstrated that SaDec shows promising efficacy against gastrointestinal nematodes in small ruminants. [ABSTRACT FROM AUTHOR]

The secretory EF-hand Ca ++ -binding proteins act as calcium signaling molecules for control of cell functions, but those proteins from parasitic helminths are poorly understood. Here, we have identified and characterized an EF-hand Ca ++ -binding protein from the rodent nematode, Strongyloides venezuelensis , termed ‘venestatin’, which is highly conserved in Strongyloides spp. Canonical two EF-hand domains and a signal peptide are present in venestatin. A gel mobility shift assay and Ruthenium red staining indicated that the recombinant venestatin possesses binding ability with Ca ++ ions. Endogenous venestatin was seemingly localized in the hypodermis and gut of the worms and was found in the excretory-secretory products. Quantitative reverse transcription-PCR data showed that venestatin-specific transcript was upregulated in the parasitic stages of S. venezuelensis , and the upregulation occurred promptly after larval invasion through the host’s skin, but not in the case of in vitro incubation. Immunization of mice with recombinant venestatin caused a 55% reduction in larval migration to the lungs, and lung hemorrhaging was mild compared with non-immunized groups, suggesting that anti-venestatin sera may interfere with larval migration from skin to lung. Our results suggest that venestatin is secreted from the hypodermis and gut of S. venezuelensis, and has pivotal roles in larval migration. [ABSTRACT FROM AUTHOR]

Consumption of conspecific and heterospecific eggs and larvae is common in many animal taxa, including many amphibians. Adult newts (Amphibia Urodela) often co-occur temporally and spatially with conspecific and heterospecific newt eggs and larvae, and adult individuals may benefit from their consumption, but little is known on the degree of discrimination in the newts’ predatory behaviour towards them. We performed two laboratory experiments to examine whether adult male and female alpine,Ichthyosaura alpestris(Laurenti 1768), and smooth,Lissotriton vulgaris(Linnaeus 1758), newts discriminate between conspecific and heterospecific eggs and larvae in their predatory behaviour. In our study, eight out of 64 newts succeeded in consuming eggs, although 3 times as many attacked them. We found no differences in predatory behaviour towards conspecific and heterospecific eggs, or between males and females in either species. Similarly, we found no evidence for the occurrence of discriminative predatory behaviour towards conspecific and heterospecific larvae. In our experiments the criterion for whether a newt would consume a prey item (egg or larva) was not the prey’s identity (species), but the newts’ ability to detect, capture and/or ingest it. Our results suggest that newts of both species follow an opportunistic foraging strategy, consuming whatever prey of appropriate size they manage to capture. [ABSTRACT FROM AUTHOR]

Vertical distribution of planktonic larvae affects their passive horizontal transport. We investigated vertical distributions of ark shell Arcidae species larvae at successive developmental stages monthly from August to October 2009 along axial transects in Sendai Bay, an open embayment along the Pacific coast of northeastern Japan, where the ark shell Anadara broughtonii (Schrenck 1867) is the dominant arcid species. Younger larvae (early and mid-umbo stages) were typically distributed in the surface near the shore with salinity <33 psu. Older larvae (late umbo and competent stages) were distributed in the bottom far from the shore with salinity >33 psu. Surface axial distributions of younger larvae were marginally affected by the river discharge volume, tidal height and southerly wind strength. The younger and older larvae were distributed closer inshore and further offshore than the main habitat of the adults, respectively. Therefore, younger larvae were first transported inshore and moved upward to the surface layer, and then transported offshore, increasing their distribution depth. These results indicate that ark shell larvae ontogenetically change their swimming behaviour to increase their distribution depth and their axial distribution patterns may be explained by the different flow patterns among the layers of the water column in Sendai Bay. [ABSTRACT FROM AUTHOR]

Nervous system organization differs greatly in larvae and adults of many species, but has nevertheless been traditionally used for phylogenetic studies. In phoronids, the organization of the larval nervous system depends on the type of development. With the goal of understanding the ground plan of the nervous system in phoronid larvae, the development and organization of the larval nervous system were studied in a viviparous phoronid species. The ground plan of the phoronid larval nervous system includes an apical organ, a continuous nerve tract under the preoral and postoral ciliated bands, and two lateral nerves extending between the apical organ and the nerve tract. A bilobed larva with such an organization of the nervous system is suggested to be the primary larva of the taxonomic group Brachiozoa, which includes the phyla Brachiopoda and Phoronida. The ground plan of the nervous system of phoronid larvae is similar to that of the early larvae of annelids and of some deuterostomians. The protostome- and deuterostome-like features, which are characteristic of many organ systems in phoronids, were probably inherited by phoronids from the last common bilaterian ancestor. The information provided here on the ground plan of the larval nervous system should be useful for future analyses of phoronid phylogeny and evolution. [ABSTRACT FROM AUTHOR]

Used as a traditional Chinese medicine, the high mortality rate and slow growth of Whitmania pigra larvae are the most serious bottlenecks for the scale development of artificial breeding. Firstly, five light colour treatments (white, blue, green, red and yellow) were tested to determine effects of light spectrum on the growth of larval W. pigra at the same intensity of 70.00 μmol m−2 s−1. The experiment lasted for 45 days. Under our experimental conditions, the weight gain (WG) and the specific growth rate (SGR) under blue light condition were significantly higher compared with the other treatments ( P ≤ 0.05). It is reasonable to conclude that blue light can promote the leech growth. In addition, reared at five blue light intensity treatments (20.00 ± 3.84, 40.78 ± 4.18, 53.67 ± 5.98, 70.00 ± 7.26 and 87.33 ± 5.77 μmol m−2 s−1), the WG and SGR increased with increasing intensity. Meanwhile, they were significantly higher in the 70.00 and 87.33 μmol m−2 s−1 treatments ( P ≤ 0.05). In the higher intensity light treatments, the digestive enzymes were higher and antioxidant enzymes were lower. These results suggest that the optimal light spectrum for the culture of W. pigra during the early life stage was blue and the optimal light intensity was higher light intensity (70.00-87.33 μmol m−2 s−1). [ABSTRACT FROM AUTHOR]

Light is a key environmental factor that influences the growth, culture and survival of aquatic organisms. This study examined the effects of different light qualities (red, orange, white, blue and green light) and intensities (5 μmol m−2 s−1, 15 μmol m−2 s−1 and 40 μmol m−2 s−1) on the hatching and metamorphosis of larva of Haliotis discus hannai Ino and the growth and survival of juveniles. It was found that under blue and green light, the hatching success rate and metamorphosis of larva were significantly higher than those for any other light quality ( P < 0.05), and there was a decreasing trend with an increase in light intensity. Under red and orange light, the abnormality rate of trochophores in each light intensity treatment and the time required for the metamorphosis of larva were significantly higher than those for any other light group ( P < 0.05). Both the abnormality and metamorphosis rates significantly increased with light intensity. Under white light, at an intensity of 40 μmol m−2 s−1, the settlement and size of larva at metamorphosis were significantly smaller than those for any other light intensity ( P < 0.05). Under red and orange light, the SGR of juvenile abalone in each light intensity treatment was significantly lower than that in any other light group ( P < 0.05), but no significant difference was identified ( P > 0.05). Therefore, selecting blue and green light and controlling the light intensity to 5-15 μmol m−2 s−1 during fingerling reproduction of abalone should increase the hatching success rate of larva and the yield per water body. [ABSTRACT FROM AUTHOR]

With projected changes in the marine environment under global climate change, the effects of single stressors on corals have been relatively well studied. However, more focus should be placed on the interactive effects of multiple stressors if their impacts upon corals are to be assessed more realistically. Elevation of sea surface temperature is projected under global climate change, and future increases in precipitation extremes related to the monsoon are also expected. Thus, the lowering of salinity could become a more common phenomenon and its impact on corals could be significant as extreme precipitation usually occurs during the coral spawning season. Here, we investigated the interactive effects of temperature [24, 27 (ambient), 30, 32°C] and salinity [33 psu (ambient), 30, 26, 22, 18, 14 psu] on larval settlement, post-settlement survival and early growth of the dominant coral Platygyra acuta from Hong Kong, a marginal environment for coral growth. The results indicate that elevated temperatures (+3°C and +5°C above ambient) did not have any significant effects on larval settlement success and post-settlement survival for up to 56 days of prolonged exposure. Such thermal tolerance was markedly higher than that reported in the literature for other coral species. Moreover, there was a positive effect of these elevated temperatures in reducing the negative effects of lowered salinity (26 psu) on settlement success. The enhanced settlement success brought about by elevated temperatures, together with the high post-settlement survival recorded up to 44 and 8 days of exposure under +3°C and +5°C ambient respectively, resulted in the overall positive effects of elevated temperatures on recruitment success. These results suggest that projected elevation in temperature over the next century should not pose any major problem for the recruitment success of P. acuta. The combined effects of higher temperatures and lowered salinity (26 psu) could even be beneficial. Therefore, corals that are currently present in marginal environments like Hong Kong, as exemplified by the dominant P. acuta, are likely to persist in a warmer and intermittently less saline, future ocean. [ABSTRACT FROM AUTHOR]

The culture of the common octopus (Octopus vulgaris) is promising since the species has a relatively short lifecycle, rapid growth, and high food conversion ratios. However, recent attempts at successful paralarvae culture have failed due to slow growth and high mortality rates. Establishing an optimal nutritional regime for the paralarvae seems to be the impeding step in successful culture methods. Gaining a thorough knowledge of food regulation and assimilation is essential for paralarvae survival and longevity under culture conditions. The aim of this study, then, was to elucidate the characteristic metabolic organization of octopus paralarvae throughout an ontogenic period of 12 days post-hatching, as well as assess the effect of diet enrichment with live prey containing abundant marine phospholipids. Our results showed that throughout the ontogenic period studied, an increase in anaerobic metabolism took place largely due to an increased dependence of paralarvae on exogenous food. Our studies showed that this activity was supported by octopine dehydrogenase activity, with a less significant contribution of lactate dehydrogenase activity. Regarding aerobic metabolism, the use of amino acids was maintained for the duration of the experiment. Our studies also showed a significant increase in the rate of oxidation of fatty acids from 6 days after-hatching. A low, although sustained, capacity for de novo synthesis of glucose from amino acids and glycerol was also observed. Regardless of the composition of the food, glycerol kinase activity significantly increased a few days prior to a massive mortality event. This could be related to a metabolic imbalance in the redox state responsible for the high mortality. Thus, glycerol kinase might be used as an effective nutritional and welfare biomarker. The studies in this report also revealed the important finding that feeding larvae with phospholipid-enriched Artemia improved animal viability and welfare, significantly increasing the rate of survival and growth of paralarvae. [ABSTRACT FROM AUTHOR]

Branchiomma bairdi is a Caribbean fan worm introduced in several localities worldwide, including the Mediterranean Sea, where the species' range has rapidly expanded. Reproduction in B. bairdi was previously investigated in both extra-Mediterranean and Mediterranean areas, but no information is available on larval development and post-larval growth. In the present article, we examined these features for a population from the Mar Grande of Taranto (Ionian Sea). The species is hermaphrodite, and fertilization occurs in situ. Mucus seems to play an important role in fertilization, and also in preserving eggs before fertilization. The trochophore stage develops within the mucus and after hatching, larvae swim for about 3 d before settlement. The trochophore showed a distinct prototroch and two red dorsolateral larval eyes. The pelagic stage takes only 96 h even though prototroch is maintained after settlement, disappearing at 5 d, when larvae showed three chaetigers and branchial crown consisted of four radioles. Some interesting observations concerning changes in the morphology of chaetae and in the number of uncini during growth are also reported, together with discussion of the development of stylodes, an important diagnostic feature in Branchiomma species identification. [ABSTRACT FROM AUTHOR]

The reproduction of captive Pleurodeles nebulosus was followed during five breeding seasons. The breeding season lasted from the onset of autumn to early spring. Most eggs were laid in October, although oviposition occurred throughout the breeding season. Each season a female would produce one or more clutches of 19-224 eggs. Diameter of the ova was 1.63-1.65 mm. Eggs hatched after 8-12 days, and at hatching the larvae were in Harrison stages 37-38. It took 73-108 days for the larvae to reach metamorphosis and the metamorphs measured 25.6-32.1 mm in standard length. A modest correlation was found between standard length at metamorphosis and larval development time. Juveniles, which were kept aquatic, reached maturity after 9-10 months, whereas juveniles, which were reared on land, did not reach maturity until approx. 20-22 months after metamorphosis. [ABSTRACT FROM AUTHOR]

We present here the first laboratory study on the effects of pharmacologically active compounds on the larval metamorphosis of the New Zealand geoduck, Panopea zelandica (Quoy and Gaimard, 1835). Two batches of competent hatchery-reared larvae were exposed to acetylcholine chloride, epinephrine hydrochloride and excess potassium ions in the form of KCl and K2 SO4. None of the tested chemicals increased the proportion of metamorphosed geoducks, and in some cases, the chemical caused significant mortality, despite having been used extensively with other species, such as mussels and oysters. This might indicate that geoduck larval physiology and development differs from other bivalves. Geoducks may have evolved distinct chemoreceptor patterns that facilitate metamorphosis under environmentally favourable conditions for subtidal soft sediment habitats suitable for burrowing. Thus, further research is needed to identify alternative cues (e.g. conspecific adults, sediment characteristics and surface biofilm) and understand their role in settlement and metamorphosis. This information will aid the design of reseeding methods and contribute to the development of reliable hatchery production of geoduck spat. [ABSTRACT FROM AUTHOR]

The study was aimed at to investigate the anthelmintic efficacy of aqueous and ethanolic extracts of Cucurbita pepo against gastrointestinal nematodes of sheep by scientifically validated in vitro and in vivo tests. In vitro anthelmintic activity was determined by egg hatch assay, larval migration inhibition assay and larval development assay against eggs and larvae of mixed gastrointestinal nematodes of sheep. The extracts which were found to be effective in in vitro assays were further evaluated by in vivo faecal egg count reduction test against mixed species of sheep gastrointestinal nematodes with 3 different doses (125, 250 and 500 mg kg-1). Haematological and serum parameters were estimated before and after treatment to determine the impact of plant extracts on health of the animal. Aqueous extract of C. pepo demonstrated significant inhibition of egg hatch at 40 and 80 mg/ml. The ED50 value of egg hatch inhibition was 3.51mg/ml. In larval migration inhibition assay, both aqueous and ethanolic extracts of C. pepo demonstrated inhibition of larval migration and the LM50 was 1.75 and 0.32 mg/ml respectively. However, in larval development assay, both aqueous and ethanolic extracts showed only marginal inhibition of larval development at all concentrations tested. In faecal egg count reduction test (FECRT), aqueous extracts of C. pepo at 500 mg/kg caused significant reduction in eggs per gram (96.61 per cent) the reduction being higher than the result obtained with albendazole, the positive control (93.25 per cent). There was a significant difference in EPG reduction between sheep treated with albendazole and C. pepo. Haematological and serum parameters were not affected in both the treated and untreated sheep indicating that the extracts did not cause toxic effects. Based on the results obtained in this study, the aqueous extract of C. pepo possesses anthelmintic activity and could offer an alternative source for the control of gastrointestinal nematodes of sheep. [ABSTRACT FROM AUTHOR]

In marine environments, connectivity among populations of benthic invertebrates is provided primarily by dispersion of larvae, with the duration of pelagic larval phase (PLD) supposed to represent one of the major factor affecting connectivity. In marine gastropods, PLD is linked to specific larval development types, which may be entirely intracapsular (thus lacking a pelagic dispersal), or include a short pelagic lecithotrophic or a long planktotrophic phase. In the present study, we investigated two sibling species of the cosmopolitan neogastropod genus Columbella (commonly known as dove shells): Columbella adansoni Menke, 1853, from the Macaronesian Atlantic archipelagos, with planktotrophic development, and Columbella rustica Linnaeus, 1758, from the Mediterranean Sea, with intracapsular development. We expected to find differences between these two sister species, in terms of phylogeographic structure, levels of genetic diversification and spatial distribution of genetic diversity, if PLD was actually a relevant factor affecting connectivity. By analysing the sequence variation at the cytochrome c oxidase subunit I (COI) in 167 specimens of the two species, collected over a comparable geographic range, we found that Columbella adansoni, the species with planktotrophic development, and thus longer PLD, showed no phylogeographic structure, lower levels of genetic diversity, interpopulational variance lower than the intrapopulational one and no spatial structure in the distribution of the genetic diversity; Columbella rustica , the species with intracapsular development, thus with evidently lower dispersal abilities, showed a clear phylogeographic structure, higher levels of genetic diversity, high interpopulational and low intrapopulational variance, and a clear signature of global spatial structure in the distribution of the genetic diversity. Thus, in this study, two sibling species differing almost only in their larval ecology (and PLD), when compared for their genetic variation showed patterns supporting the hypothesis that PLD is a major factor affecting genetic connectivity. Therefore, it seems reasonable to expect that the ecological attributes of the marine communities - also in terms of the variation in larval ecology of the species involved – are taken into the due consideration in conservation actions, like the design of marine protected areas networks. [ABSTRACT FROM AUTHOR]

Myctophid fish are an important component of the Southern Ocean food web because of their very high biomass. This study investigated the spatial distributions of larval and juvenile/adult stages of the Antarctic myctophid Electrona antarctica . Fish were sampled in January 2011 and 2012 on a transect along 140°E and in January 2013 along 110°E using two different opening/closing net systems. In total, 1075 specimens of E . antarctica were collected: 948 larvae, 127 juveniles/adults, and 2 in the transformation stage. Most larvae were collected at 5–200 m depth, with diel vertical migration (DVM) not apparent. Larvae were mainly distributed in the Modified Circumpolar Deep Water (−1.5 °C–2.0 °C). By contrast, an analysis of the echogram at 38 kHz and discrete depth samples implied that juveniles/adults undertook DVM except in the continental slope area (65.5°S). As the distribution of krill is limited to the cold water mass (<–1.5 °C) along the continental slope, E . antarctica and krill populations are spatially separated off Wilkes Land during summer. According to the previously estimated larval period of 30–47 days, E. antarctica may spawn in late November to December in the marginal ice zone or near the sea ice edge. This study suggests that the environment related to sea ice provides a nursery ground for early stage larvae of E. antarctica . [ABSTRACT FROM AUTHOR]

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Polydora websteribelongs to a group of the Spionidae known as thePolydoracomplex, members of which are known for building tubes within the shells of mussels and for their ability to infest commercially valuable bivalves, which causes serious losses for malacoculture.P. websteriis a species subjected to increasing research due to the global scale at which these infestations occur. In this paper, we describe the larval development ofP.cf.websteriassociated with the oysterCrassostreacf.brasilianain a tropical region of north-east Brazil. The main structures of all stages of development were analysed and compared to other populations ofP.websteri. Ovigerous capsules ofP.cf.websteriwere cultured in the laboratory and the larval stages were analysed until metamorphosis. Ovigerous capsules were present in all sampling intervals, indicating that this population exhibits continuous reproduction. Up to 21 capsules per tube were found, and the number of eggs per capsule varied from 20 to 40. All observed eggs developed into larvae. Larval development from egg to recruitment stage did not exceed 13 days. Metamorphosis occurred when larvae attained 17 chaetigers, at which stage important diagnostic characteristics were revealed, such as the spines on chaetiger 5. The developmental stages ofP.cf.websterilarvae, and the morphological features found at each stage, are in accordance with what has been recorded for temperate populations. In our study, the planktonic stage was found to be of shorter duration than elsewhere, which might be associated with the higher temperatures at which larvae were cultured compared to previous studies. [ABSTRACT FROM AUTHOR]

The distribution of the sea urchin Arbacia lixula, a warm affinity species, has been expanding in the Mediterranean Sea. To address questions on potential for future success of this species in the region, the thermotolerance of larval development was investigated in context of regional warming. The larvae were reared in present day spawning period (20 °C) and warming conditions (+4 = 24 and + 6 = 26 °C). As the calcifying larvae of sea urchins are vulnerable to stunted growth caused by ocean acidification, the impact of lower pH (--0.3 pH units) on larval development was also investigated in combination with warming. Morphological traits of the larvae, post-oral length arms, overall length of larvae and body length, were affected by increased temperature across pH treatments, indicating that for the larvae of southern Mediterranean population here, 24°C appears to approximate the optimal temperature for development. A slightly negative effect of pH was evident. Increased temperature ameliorated the stunting effect of acidification on growth. The thermal tolerance of A. lixula development overlaps with projections for warming in the region by 2100 and also indicates that this species has acclimatized or adapted its reproductive biology to the broad environmental conditions of the Mediterranean Sea. Due to the broad thermal range (~10 ° C) of development of A. lixula across its distribution, this species is likely to be a winner in the climate change stakes. The broad thermal tolerance of the larvae is likely to assure population connectivity between Mediterranean sub-basins populations. The continued success of A. lixula can have a strong consequences for the ecological structure of Mediterranean rocky habitat. [ABSTRACT FROM AUTHOR]

Background: Vector control is facing a menace due to the appearance of resistance to synthetic insecticides. Insecticides of plant origin may provide appropriate substitute biocontrol techniques in the future. The present study was carried out to investigate the bio control potentiality of active ingredient isolated from chloroform: methanol (1:1 v/v) extract of mature leaves of Solanum nigrum L. (Solanaceae) against early 3rd instar larvae of Culex vishnui group (comprising of Cx. vishnui Theobald, Cx. pseudovishnui Colless and Cx. tritaeniorhynchus Giles) and Anopheles subpictus Grassi. S. nigrum is a common plant distributed in many parts of India with medicinal properties. Methods: Bioactive compound isolated from chloroform: methanol (1:1 v/v) extract of mature leaves of S. nigrum was (25, 45, 60 mg/L) tested against early 3rd instar larvae of Cx. vishnui group and An. subpictus. The lethal concentration was determined by log probit analysis. The chemical nature of the active substance was also evaluated following gas chromatography-mass spectroscopy (GC-MS) and infrared (IR) analysis. The compound was also studied on non target organisms such as Daphnia sp. and Diplonychus annulatum. Results: TLC spot having Rf value of 0.94 (Rf = 14.1/15 = 0.94) showed larvicidal activity. In a 72 h bioassay experiment, mortality rate at 60 mg/L was significantly higher (P < 0.05) than those at 25 and 45 mg/L against early 3rd instar. Result of log-probit analysis (at 95% confidence level) revealed that LC50 and LC90 values gradually decreased with the exposure period showing the lowest value at 72 h of exposure. A clear dose-dependent mortality was observed, as the rate of mortality (Y) was positively correlated with the concentration (X) having regression coefficient value close to one in each case. The compound was found to be eco-friendly as it did not show any adverse effect to the studied non target organisms. Chemical characterization (GC-MS and IR analyses) of the active ingredient revealed the presence of phytosteroid compounds responsible for mosquito larvicidal activity. Conclusion: Leaf extract of S. nigrum has great potential as bio control agent against Cx. vishnui group and An. subpictus. In near future the isolated bioactive phytochemical could be used as a source of an effective mosquitocidal agent. [ABSTRACT FROM AUTHOR]

As the earth's climate has warmed, many tropical species have expanded their ranges poleward and encountered high-latitude seasonal temperature regimes, in which further permanent expansion is limited by physiological vulnerability to cold temperatures. The barnacle Megabalanus coccopoma is native to shorelines from Baja California to Peru and has been introduced to many locations worldwide, including the southeastern USA. The ability of larvae to develop successfully at local temperatures can be an important factor limiting the spread of invasive species. To determine if cold temperatures limited larval success near the northern range limit of M. coccopoma along the Atlantic southeastern USA coast, we measured lower temperature limits to larval development, examined the effects of temperature on larval growth and energy accumulation, and calculated a larval energy budget to estimate the extent of potential larval dispersal in this region. Larvae were able to develop through metamorphosis at 16°C, which is much colder than sea surface temperatures during the spawning season in their invasive range, making it unlikely northern range limits are set by a lower temperature limit to larval development. Energy budgets suggest that for larvae produced at the northern end of the invasive range, long distance dispersal to sites far poleward of the current range limit is possible. Similar to the findings of the handful of other studies on cold tolerances of tropical marine invertebrate larvae, larvae should be successful far poleward of current adult distributions. [ABSTRACT FROM AUTHOR]

Whereas the external larval morphology of some species of Adenomera has been described, their internal morphology remains poorly studied. In this work, we provide information on the reproductive features and larval morphology of populations of Adenomera from northeastern Argentina and southwestern Brazil, including the first description of the chondrocranium and hyobranchial apparatus for a member of the genus Adenomera. We found that, morphologically, the buccal cavity of A. diptyx is more similar to that of the species of the Leptodactylus fuscus group than to that of A. marmorata, the only species of Adenomera whose buccal cavity is known. Adenomera diptyx shares with the species of the L. fuscus group a semicircular crest in the prenarial region, two pairs of infralabial papillae, four lingual papillae, and few papillae on the roof and the floor of the cavity. The chondrocranial morphology of A. diptyx exhibits all the characters that characterise all members of the genus Leptodactylus and several characters that are shared with the L. fuscus group: wide suprarostrals with U-shaped corpora in frontal view, long and narrow cornua, long and finger-like processi anterolaterali on the otic capsules, a posterior curvature of the palaquadrate at the level of the point of attachment of the processus ascendens of the orbital cartilage, a processus ascendens that is almost perpendicular to the main axis of the body, a connection between the processus ascendens and the orbital cartilage just posterior to the oculomotor foramen, and a processus branchialis that is open between ceratobranchials II and III. Considering that the phylogenetic relationships between Adenomera and Leptodactylus are still discussed and that information on the larval morphology of Adenomera species is scarce, new studies are necessary for a more exhaustive analysis, including further data about the internal larval morphology of Adenomera species. [ABSTRACT FROM AUTHOR]

Effects of select pharmacological compounds, with known mode of action in vertebrates, were evaluated on the development, metabolism and settlement of larvae of the common fouling barnacle, Amphibalanus amphitrite . Atrovastatin, a lipid-regulating compound, cetrizine hydrochloride, an anti-histamine, atenolol, a β-blocker, and amlodipine, a calcium-channel blocker were the compounds studied. Nauplii treated with these compounds took more days to reach the cypris stage when compared with the control. These compounds also inhibited the settlement of cyprids on Petri dishes. While exposure to these compounds led to a decrease in the metabolic activity of stage III nauplii, it increased the respiratory rate of cyprids. The results emphasize the role of neurotransmitters and lipids in the development and settlement of barnacle larvae on hard surfaces. [ABSTRACT FROM AUTHOR]

Background: Phagocyte-derived extracellular traps (ETs) were recently demonstrated mainly in vertebrate hosts as an important effector mechanism against invading parasites. In the present study we aimed to characterize gastropod-derived invertebrate extracellular phagocyte trap (InEPT) formation in response to larval stages of important canine and feline metastrongyloid lungworms. Gastropod haemocytes were isolated from the slug species Arion lusitanicus and Limax maximus, and the snail Achatina fulica, and exposed to larval stages of Angiostrongylus vasorum, Aelurostrongylus abstrusus and Troglostrongylus brevior and investigated for gastropod-derived InEPT formation. Results: Phase contrast as well as scanning electron microscopy (SEM) analyses of lungworm larvae-exposed haemocytes revealed ET-like structures to be extruded by haemocytes thereby contacting and ensnaring the parasites. Co-localization studies of haemocyte-derived extracellular DNA with histones and myeloperoxidase in larvae-entrapping structures confirmed classical characteristics of ETs. In vivo exposure of slugs to A. vasorum larvae resulted in InEPTs being extruded from haemocytes in the slug mucous extrapallial space emphasizing the pivotal role of this effector mechanism against invasive larvae. Functional larval entrapment assays demonstrated that almost half of the haemocyte-exposed larvae were contacted or even immobilized by released InEPTs. Overall, as reported for mammalian-derived ETs, different types of InEPTs were here observed, i.e. aggregated, spread and diffused InEPTs. Conclusions: To our knowledge, this study represents the first report on metastrongyloid lungworm-triggered ETosis in gastropods thereby providing evidence of early mollusc host innate immune reactions against invading larvae. These findings will contribute to the better understanding on complex parasite-intermediate host interactions since different gastropod species bear different transmitting capacities for metastrongyloid infections. [ABSTRACT FROM AUTHOR]

Summary Many animals are indirect developers with distinct larval and adult body plans [ 1 ]. The molecular basis of differences between larval and adult forms is often poorly understood, adding a level of uncertainty to comparative developmental studies that use data from both indirect and direct developers. Here we compare the larval and adult body plans of an indirect developing hemichordate, Schizocardium californicum [ 2 ]. We describe the expression of 27 transcription factors with conserved roles in deuterostome ectodermal anteroposterior (AP) patterning in developing embryos, tornaria larvae, and post-metamorphic juveniles and show that the tornaria larva of S. californicum is transcriptionally similar to a truncated version of the adult. The larval ectoderm has an anterior molecular signature, while most of the trunk, defined by the expression of hox1 – 7 , is absent. Posterior ectodermal activation of Hox is initiated in the late larva prior to metamorphosis, in preparation for the transition to the adult form, in which the AP axis converges on a molecular architecture similar to that of the direct developing hemichordate Saccoglossus kowalevskii . These results identify a molecular correlate of a major difference in body plan between hemichordate larval and adult forms and confirm the hypothesis that deuterostome larvae are “swimming heads” [ 3 ]. This will allow future comparative studies with hemichordates to take into account molecular differences caused by early life history evolution within the phylum. Additionally, comparisons with other phyla suggest that a delay in trunk development is a feature of indirect development shared across distantly related phyla. [ABSTRACT FROM AUTHOR]

Mosquitoes host communities of microbes in their digestive tract that consist primarily of bacteria. We previously reported that Aedes aegypti larvae colonized by a native community of bacteria and gnotobiotic larvae colonized by only Escherichia coli develop very similarly into adults, whereas axenic larvae never molt and die as first instars. In this study, we extended these findings by first comparing the growth and abundance of bacteria in conventional, gnotobiotic, and axenic larvae during the first instar. Results showed that conventional and gnotobiotic larvae exhibited no differences in growth, timing of molting, or number of bacteria in their digestive tract. Axenic larvae in contrast grew minimally and never achieved the critical size associated with molting by conventional and gnotobiotic larvae. In the second part of the study we compared patterns of gene expression in conventional, gnotobiotic and axenic larvae by conducting an RNAseq analysis of gut and nongut tissues (carcass) at 22 h post-hatching. Approximately 12% of Ae. aegypti transcripts were differentially expressed in axenic versus conventional or gnotobiotic larvae. However, this profile consisted primarily of transcripts in seven categories that included the down-regulation of select peptidases in the gut and up-regulation of several genes in the gut and carcass with roles in amino acid transport, hormonal signaling, and metabolism. Overall, our results indicate that axenic larvae exhibit alterations in gene expression consistent with defects in acquisition and assimilation of nutrients required for growth. [ABSTRACT FROM AUTHOR]

A variety of early ontogenetic events of anuran species (growth, structural and biochemical diversification, metamorphosis) offers a unique opportunity to evaluate the effectiveness and application limits of mass spectrometry method for the analysis of metabolic and transformation events in developing organisms. The dynamics of relative carbon and nitrogen contents and stable isotopes of these elements during larval development in the period of metamorphosis climax and after its conclusion in moor frog specimens developing in their natural habitat and in vitro on a referent diet are traced. A decrease in C/N ratio and enrichment of the tissues with heavy stable isotopes of carbon and nitrogen during embryonal and larval development (prior to the beginning of independent feeding) indicates the increase in the portion and variety of proteins, accompanied by consumption of yolk lipids. The relative nitrogen content increase and C/N ratio decreases with the growth and development of independently feeding tadpoles, which indicates surpassing increase of the portion of proteins in tissues. In growing tadpoles, the rates of tissue renewal in general and rates of protein metabolism in particular affect the kinetics of changes of tissue isotope composition, which approaches isotope composition of the consumed food. A decrease in С/N ratio in the bodies of metamorphs during mass tissue decomposition is indicative of continuing reconstruction of larval organs and growth of anlage of definitive organs. Significant increase of C/N ratio and depletion of liver samples by heavy carbon isotopes are associated with intensive synthesis and reservation of lipids within the organ. Strong enrichment of metamorphs' tissues with heavy nitrogen isotope indicates the substitution of ammoniotelic type of nitrogen metabolism by urotelic type. Decrease in C/N ratio and enrichment of tissues by heavy carbon isotope may be connected to intensive oxidation of lipids, which supports the growing energy costs of terrestrial underyearlings. Relative contents of heavy nitrogen isotope in the tissues of underyearlings does not change compared to the tissues of metamorphs. [ABSTRACT FROM AUTHOR]

Semanotus japonicus larvae feed on the phloem of living trees of Cryptomeria japonica and Chamaecyparis obtusa, and newly emerged adults stay in xylem from August through the following April when they emerge from the trees. A positive correlation is known between the female body mass and lifetime fecundity in this insect. To determine the timing of maturation in reproductive organs and the relationships of female body size to the total number of ovarioles of a female (ovariole number) and egg production per ovariole, we dissected adults taken from dead trees from October through the following April. Dissecting females showed that well-developed eggs began to appear in the calyx in April, that the ovariole number ranged from 34 to 79, and that the ovariole number per female and egg production per ovariole increased as the female body mass increased, indicating that the body size-dependent lifetime fecundity was attributed to greater ovariole number and greater egg production per ovariole for large females. Dissecting males taken from dead trees and reared on C. obtusa bolts showed that a great deal of sperms were found in testes and seminal vesicles in October and that a long-term exposing to 25°C at a photoperiodic regime of 16-h photophase and 8-h scotophase broke down the testes internally in which sperms disappeared. Body-size dependency of ovariole number was discussed in relation to the adult feeding and phylogeny. [ABSTRACT FROM AUTHOR]

In risk assessment, honey bees are used as a model organism to evaluate the effects of pesticides on pollinators. Honey bees forage on pollen and nectar, which are the nutritional basis for the nurse bees to produce the food jelly they feed to the larvae of all castes and sexes. It has been proven in several studies that pesticide residues can be found in different bee related products like wax, beebread, or honey and thus a further transfer into the larval food jelly might be possible. Here, we aim to summarize and analyze the current literature dealing with residue analysis of pesticides in food jelly. Furthermore, we assess the amount of contaminants remaining in jelly, to evaluate factors influencing their occurrences, and to deduce risk for larvae. Most of the studies focus on the detection of residues in royal jelly, while only one focused on worker jelly. It was demonstrated that 30 out of 176 analyzed pesticides were detectable in a range of 0.005 to 3860.25 ng/g in different royal jelly samples. The application and exposure method are the main factors influencing if residues remain detectable in food jellies. All detected concentrations were predominantly below toxicological values for bee larvae, but sub-lethal effects should not be neglected. Nevertheless, there is still information missing about the contamination pathway of pesticides, dilution or accumulation factors within the hive, degradation time in bee-related matrices, and impact on larval physiology, which should be completed to allow for sufficient protection levels of honey bees. [ABSTRACT FROM AUTHOR]

The susceptibility of the northern corn rootworm Diabrotica barberi (Smith & Lawrence) to mCry3A and eCry3.1Ab proteins derived from Bacillus thuringiensis (Bt) was determined using a diet bioassay. Northern corn rootworm neonates were exposed to different concentrations of mCry3A and eCry3.1Ab, incorporated into artificial diet. Larval mortality was evaluated after 7 d. The mCry3A and eCry3.1Ab proteins were found to be toxic to the northern corn rootworm larvae. The LC50 and LC99 values for mCry3A were 5.13 and 2482.31 μg/mL, respectively. For eCry3.1Ab, the LC50 and LC99 values were 0.49 and 213.01 μg/mL. Based on the estimated lethal concentrations, eCry3.1Ab protein was more efficacious to northern corn rootworm larvae than mCry3A. These lethal concentration values will be used as diagnostic doses for routine annual monitoring for change in susceptibility of field collected northern corn rootworm to mCry3A, and eCry3.1Ab toxins. [ABSTRACT FROM AUTHOR]

Branches of Quercus species killed by Coraebus florentinus (Coleoptera, Buprestidae) are a chief resource for many saproxylic insects, mainly of the orders Coleoptera and Diptera, in the oak forests of the southern Iberian Peninsula. To investigate the biology of these species, a total of 127 dry oak branches that had been previously colonised by C. florentinus were collected and kept in the laboratory, in conditions comparable to the outdoor climate. For 4 years, the emergence of saproxylic insects from the branches was monitored. We obtained 651 individuals, belonging to 19 species of 6 families. Three buprestids ( Anthaxia hungarica, A. millefolii and Agrilus angustulus) and one cerambycid ( Chlorophorus ruficornis) made up 68% of the total abundance. Results on host tree preferences indicated that A. hungarica and C. ruficornis show more affinity to holm oaks ( Q. ilex). Conversely, A. angustulus and A. hastulifer prefer cork oaks ( Q. suber). Preimaginal stages have long durations, but vary in relation to the body size of species: smaller species such as A. angustulus and A. millefolii exhibit shorter larval time, reaching the maximum of emergences after 12 months monitoring, whereas larger species such as A. hungarica and C. ruficornis display a longer pre-adult period (3 and 4 years, respectively). The insects were found to be active in spring and summer and to have a balanced sex ratio in all of the species studied. Finally, our results also indicate the importance of long-term maintenance of these branches in the natural environment for the conservation of saproxylic biodiversity in the Iberian 'dehesa'. [ABSTRACT FROM AUTHOR]

Events in the early life history of reef-building corals, including fertilisation and larval survival, are susceptible to changes in the chemical and physical properties of sea water. Quantifying how changes in water quality affect these events is therefore important for understanding and predicting population establishment in novel and changing environments. A review of the literature identified that levels of salinity, temperature, pH, suspended sediment, nutrients and heavy metals affect coral early life-history stages to various degrees. In this study, we combined published experimental data to determine the relative importance of sea water properties for coral fertilisation success and larval survivorship. Of the water properties manipulated in experiments, fertilisation success was most sensitive to suspended sediment, copper, salinity, phosphate and ammonium. Larval survivorship was sensitive to copper, lead and salinity. A combined model was developed that estimated the joint probability of both fertilisation and larval survivorship in sea water with different chemical and physical properties. We demonstrated the combined model using water samples from Sydney and Lizard Island in Australia to estimate the likelihood of larvae surviving through both stages of development to settlement competency. Our combined model could be used to recommend targets for water quality in coastal waterways as well as to predict the potential for species to expand their geographical ranges in response to climate change. [ABSTRACT FROM AUTHOR]

The venerid clam ( Mactra veneriformis Reeve 1854) is one of the main cultured bivalve species in intertidal and shallow subtidal ecosystems along the west coast of Korea. To understand the effects of ocean acidification on the early life stages of Korean clams, we investigated shell growth and abnormality rates and types in the D-shaped, umbonate veliger, and pediveliger stages of the venerid clam M. veneriformis during exposure to elevated seawater pCO. In particular, we examined abnormal types of larval shell morphology categorized as shell deformations, shell distortions, and shell fissures. Specimens were incubated in seawater equilibrated with bubbled CO-enriched air at (400±25)×10 (ambient control), (800±25)×10 (high pCO), or (1 200±28)×10 (extremely high pCO), the atmospheric CO concentrations predicted for the years 2014, 2084, and 2154 (70-year intervals; two human generations), respectively, in the Representative Concentration Pathway (RCP) 8.5 scenario. The mean shell lengths of larvae were significantly decreased in the high and extremely high pCO groups compared with the ambient control groups. Furthermore, under high and extremely high pCO conditions, the cultures exhibited significantly increased abundances of abnormal larvae and increased severity of abnormalities compared with the ambient control. In the umbonate veliger stage of the experimental larvae, the most common abnormalities were shell deformations, distortions, and fissures; on the other hand, convex hinges and mantle protuberances were absent. These results suggest that elevated CO exerts an additional burden on the health of M. veneriformis larvae by impairing early development. [ABSTRACT FROM AUTHOR]

Larval amphibians are particularly likely to encounter variation in rearing temperature and resource availability due to variation in aquatic breeding habitats. In this study, plasticity in growth rates, larval mass, larval period, and size at metamorphosis were examined in Rana kukunoris Nikolskii, 1918 under different combinations of temperature and food level. Larval period and larval body mass was sensitive to food level, and varied with temperature. Tadpoles metamorphosed at an older age at low temperature than those reared at warm temperature. Food level was a significant affect on larval period at low temperature, but not at warm temperature. Mass was heavier for tadpoles reared at low temperatures than those reared at warm temperatures. The effect of food level depended on temperature, because larvae reared at low temperature that were offered a high food level achieved a larger size than larvae offered a low food level, but this did not occur at warm temperature. Therefore, we suggest that high food availability at low temperature prolonged developmental periods, thus larvae are larger as metamorphs than those reared at warm temperatures. [ABSTRACT FROM AUTHOR]

Climate change is imposing constant and more severe environmental challenges to coastal and marine species. Regional climate and species acclimation capacity determine the communities' ecological response to stressors. Marine heatwave events are of serious threat to species fitness and survivorship, even more to the sensitive early-history stages of ectotherms. By combining modeled regional historical data and climate change predictions with manipulative experiments, we evaluated the potential impact of marine heatwaves in a widespread and abundant planktonic larvae of the fiddler crab Leptuca thayeri. Larvae survival was affected by temperature increase with lowest survival probability under higher temperature treatments regardless of pH conditions. Larval physiology was affected by both temperature increase and pH conditions. With heatwaves becoming more frequent, hotter, and lasting longer in the region, we could expect potential reductions in the larval recruitment and stocks with cascade ecological negative effects on estuarine habitats. [Display omitted] • Larvae survival was affected by temperature increase regardless of pH conditions. • Larvae heart beating and abdominal contractions were affected by temperature and pH. • Over the past 38 years Santos/São Vicente coast had a mean SST increase of 0.85 °C. • Higher intensity and duration of heatwaves are expected to reduce larval recruitment. [ABSTRACT FROM AUTHOR]

Plant protection products like insecticides, fungicides, or herbicides are applied onto plants to protect them against pest insects or plant diseases. The collected and stored pollen and nectar serve as the nutritional resources of honey bees to produce the larval food which is fed to the larvae. Thus, contaminants could be transferred from plants, via nectar and pollen, to honey bees and further to larvae, and may lead to harmful risks. It has been proven in different studies that pesticides residues can be found in bee related products like wax, honey, and bee bread. We aimed to review and assess the amount of contaminants remaining in jelly, to evaluate factors influencing their occurrences as well as to deduce risk for larvae. Therefore, the current literature dealing with residue analysis of pesticides in larval food jelly was summarized and analyzed. Most of the studies focused on the detection of residues in royal jelly samples and found that 30 out of 176 analyzed pesticides remain detectable. They detected concentrations in a range of 0.005 to 3860.25 ng/g, which correspond to 0.00001% to 58% pesticide transfer into royal jelly. Only one study analyzed residues in worker jelly. The main factors influencing if residues remain detectable in jellies are the application and exposure methods. All detected concentrations were predominantly below the toxicological values for bee larvae. Nevertheless, there are no information about an impact on larval physiology and thus sublethal effects should not be neglected. The literature screening revealed that there are still knowledge gaps about the contamination pathway of pesticides, dilution or accumulation factors within hive, and degradation time in bee-related matrices. Those gaps should be filled to allow for sufficient protection levels of honey bees. [ABSTRACT FROM AUTHOR]

An efficient and low-cost method of examining larval movement in Drosophila melanogaster is needed to study how mutations and/or alterations in the muscular, neural, and olfactory systems affect locomotor behavior. Here, we describe the implementation of wrMTrck, a freely available ImageJ plugin originally developed for examining multiple behavioral parameters in the nematode C. elegans . Our optimized method is rapid, reproducible and does not require automated microscope setups or the purchase of proprietary software. To demonstrate the utility of this method, we analyzed the velocity and crawling paths of two Drosophila mutants that affect muscle structure and/or function. Additionally, we show that this approach is useful for tracking the behavior of adult insects, including Tribolium castaneum and Drosophila melanogaster . [ABSTRACT FROM AUTHOR]

This study suggests a new method for determining the viability of Ascaris spp. ova, based on in-vitro early-to-late stage development of ova. This method includes stages prior to larval development, providing an estimation of potential viability. After application of biosolids onto soil and exposure to 7°C, 22°C, or 37°C for 45 days, ova were microscopically distinguished as viable or non-viable according to progression through development categories. Results were compared to viability estimates from current methods that distinguish viable ova as motile larva. Results suggest conventional techniques underestimate viability, whereas the new method provides a more conservative approach. [ABSTRACT FROM AUTHOR]

Comadia redtenbacheri (Hammerschmidt) es un lepidóptero que representa un alto valor comercial para la industria mezcalera porque en diversas marcas de mezcal se incluye una larva en cada botella. La larva tiene una coloración roja intensa que se pierde al contacto con el mezcal, lo que demerita su aspecto estético, calidad, y por lo tanto la aceptación del mezcal. Con el objeto de preservar el color y la consistencia del insecto se evaluaron cinco tratamientos: mezcal (38° de alcohol etílico), alcohol etílico 70%, serie ascendente de alcohol etílico (40, 60, 80, y 96%), vinagre blanco-alcohol etílico 40% y congelación de la larva. Los resultados muestran que el vinagre blanco-alcohol etílico 40% mantiene una mayor consistencia de las larvas, mientras que la congelación fue más eficiente para la conservación de color. Comadia redtenbacheri (Hammerschmidt) is a lepidopteran insect with a high commercial value for the mezcal industry. The coloration of the developed larvae is intense red, but this colour is lost inside mezcal bottles after a few days, which diminishes their aesthetic appearance, the quality of the beverage, and the acceptance of the product. With the objective of preserving the original color and turgidity of the insect, five treatments were evaluated: mezcal (38° ethanol), 70% ethanol at 40, 60, 80, and 96% alcohol concentration, white vinegar plus 40% alcohol, and freezing. The results showed that the treatment with 40% white vinegar plus alcohol better preserved the consistency of the larvae; freezing was more efficient to preserve their color. [ABSTRACT FROM AUTHOR]

It had been previously established that ionizing irradiation either of eggs or 5th (final) instars of Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) with 50–70 Gy would suppress the flight ability and reproduction of moths that emerged. A mean dose of 40 Gy was used to γ-irradiate larvae in oranges and in artificial diet in rearing jars to determine if the larvae reared on a synthetic diet would differ in radiotolerance from those reared in oranges. The mortality of irradiated larvae was low and very similar in rearing jars and oranges. A significantly larger number of eggs were produced by moths from 5th instars irradiated in rearing jars compared to that from oranges. However, the reduction in fecundity caused by irradiation was not significantly different for moths originating from both sources. Thus the fertility of the moths from larvae irradiated in oranges and in rearing jars from 4th and 5th instars was reduced by 64.6, 37.7 and 15.1%, respectively, compared to moths from non-irradiated control larvae. These differences were statistically significant and indicated that wild T. leucotreta were less radiotolerant than their artificially reared counterparts. Significantly fewer eggs were produced by moths from non-irradiated larvae in oranges than by moths from non-irradiated larvae in rearing jars. It is unknown whether the wild moths underperformed, or conversely, if performance of the insectary moths was enhanced by artificial rearing. Nonetheless, this aspect complements the experimental differences observed between the 2 larval sources in the experiment. The use of artificially reared T. leucotreta in research aimed at the eventual validation of ionizing radiation for the phytosanitary suppression of this pest in export citrus fruit is thus justified. [ABSTRACT FROM AUTHOR]

The peach fruit moth, Carposina sasakii Matsumura (Lepidoptera: Carposinidae), is a serious pest of many pome and stone fruits and presents a quarantine problem in some export markets. To investigate the effects of irradiation on larval weight, developmental time, and mortality, 3-, 6-, 9-, 12-, and 15 d-old larvae—which were 1st, 2nd, 3rd, 4th and 5th instars, respectively—were reared within ‘Red Fuji’ apple (Malus domestica Borkh.; Rosales: Rosaceae) fruits, and gamma-irradiated at doses from 20 to 140 Gy in increments of 20 Gy. Irradiation had significant effects on larval weight, cumulative larval developmental time, and mortality. More specific findings were as follows. Body Weight. The mean body weight of late 5th instars that developed from the 4 preceding instars decreased significantly in a dose-dependent manner when larvae in any one of these preceding instars had been irradiated with gamma rays. Mean body weight reduction of late fifth instars was greatest when 3rd instars were irradiated. In contrast, when 5th instars were irradiated their mean body weight increased significantly. Cumulative Larval Development Time. The mean cumulative larval developmental times increased significantly in a dose-dependent manner in comparison to the controls when any one of the 5 instars was irradiated. Larval Mortality. Significant larval mortality occurred in the first 4 instars when any one of them had been irradiated, but none of the irradiated 5th instars died in the apple fruits, indicating that the 5th instar is the most radiotolerant larval stage. Additional Research. Further research is suggested to elucidate the mechanisms whereby the weights of 5th instars that developed from irradiated 3rd instars are substantially diminished. Also research is suggested to elucidate the mechanisms whereby the weights of irradiated 5th instars increase substantially after they have been irradiated. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The vector species Aedes albopictus (Skuse, 1894) was recorded in Turkey for the first time, near the Greek border, in 2011 and a high risk of expansion towards Aegean and Mediterranean coasts of Turkey was estimated. A preliminary study was planned to evaluate the possibility of creating a satellite mass rearing facility for this species and manage a larval rearing procedure by using the new mass-rearing technology proposed by the International Atomic Energy Agency (IAEA). For this purpose, the effects of different larval densities (1, 2, 3 and 4 larvae per ml) on the preimaginal development were evaluated by observing pupal, adult and male productivity using life cycle trials. Geometric morphometric analyses were also performed to define all phenotypic differences that occurred on the wing size and shape morphology of adult stage at the four different rearing conditions tested. A high pupation productivity was obtained with a larval density of 2 larvae/ml while adult emergence ratio was not affected by the densities tested. No significant difference was observed in shape of the wings among different densities in males and females. Nevertheless, a significant difference in female’s centroid sizes was observed between the treatment groups 1–2 and 3–4 larvae/ml and in males centroid size reared at 1 larvae/ml versus the other densities. [ABSTRACT FROM AUTHOR]

The effects of salinity on the embryonic and larvae stage of Crassostrea iredalei were investigated. Fertilised eggs and one day old D-larvae were subjected to salinities ranging from 0 to 30 ppt at temperature of 30±2°C. At salinity lower than 10 ppt, 100% mortality was observed. For embryo development, the highest survival was observed at salinity 25 ppt with 80.9±2.2% survival with no significant difference compared to 15 and 30 ppt. Shell height and length were both greatest at salinity 30 ppt. Throughout the 11 days culture, the highest larval survival occurred at salinity 15 ppt with no significant difference compared to all other salinities except 10 ppt. Larval shell sizes showed no significant differences between salinities, except for 10 ppt. Optimum culture condition for larvae growth are salinities ranging from 15 to 30 ppt whereby the larval of this species can tolerate wider range of salinity compared to other oyster species and thus, making it a competitive species to be cultured. [ABSTRACT FROM AUTHOR]