Gut Dissection Research Articles

Study of Altenia wagneriella (rebel) as a predator associated with Forda marginata from Iran.

The larvae of Altenia spp. and gall aphids are known to feed on plants related to Anacardiaceae. This study documents the aphidophagous habit of Altenia wagneriella, which was verified by molecular techniques, subsequently by the gut dissection test, and direct observation. To identify the moth larvae and adult aphids, two mitochondrial genes, cytochrome c oxidase I (COI) and cytochrome b (Cytb), were amplified by polymerase chain reaction (PCR). Nested PCR with the aphid-specific primer pairs AphidF and AphidR was used to detect aphids in the body of moth larvae. The specificity of the primers was verified by PCR analysis of DNA from moth larvae and adult aphids. The method detected aphids in moth larvae, and a band of approximately 200bp was amplified from moth larvae feeding on aphids. No cross reactions with moth larvae were observed. In the laboratory, all moth larvae feeding on aphids (Forda marginata) were also PCR positive for aphids. Gall-inducing insects are microhabitat engineers that manipulate their host to obtain a better nutrient supply, as well as protection from natural enemies and abiotic factors. This is the first recorded instance worldwide of the carnivorous larva of the moth A. wagneriella acting as an aphid predator, as well as the first record of a host insect for this species. Additionally, it is the first effort to molecularly analyze the predator-prey relationship between the moth larvae and the aphids inside the wild pistachio gall.

Establishing Silphids in the invertebrate DNA toolbox: a proof of concept.

Environmental DNA (eDNA) analyses are an increasingly popular tool for assessing biodiversity. eDNA sampling that uses invertebrates, or invertebrate DNA (iDNA), has become a more common method in mammal biodiversity studies where biodiversity is assessed via diet analysis of different coprophagous or hematophagous invertebrates. The carrion feeding family of beetles (Silphidae: Coleoptera, Latreille (1807)), have not yet been established as a viable iDNA source in primary scientific literature, yet could be useful indicators for tracking biodiversity in forested ecosystems. Silphids find carcasses of varying size for both food and reproduction, with some species having host preference for small mammals; therefore, iDNA Silphid studies could potentially target small mammal communities. To establish the first valid use of iDNA methods to detect Silphid diets, we conducted a study with the objective of testing the validity of iDNA methods applied to Silphids using both Sanger sequencing and high throughput Illumina sequencing. Beetles were collected using inexpensive pitfall traps in Alberta, Michigan in 2019 and 2022. We successfully sequenced diet DNA and environmental DNA from externally swabbed Silphid samples and diet DNA from gut dissections, confirming their potential as an iDNA tool in mammalian studies. Our results demonstrate the usefulness of Silphids for iDNA research where we detected species from the genera Anaxyrus, Blarina, Procyon, Condylura, Peromyscus, Canis, and Bos. Our results highlight the potential for Silphid iDNA to be used in future wildlife surveys.

Co-habiting ants and silverfish display a converging feeding ecology

BackgroundVarious animal taxa have specialized to living with social hosts. Depending on their level of specialization, these symbiotic animals are characterized by distinct behavioural, chemical, and morphological traits that enable close heterospecific interactions. Despite its functional importance, our understanding of the feeding ecology of animals living with social hosts remains limited. We examined how host specialization of silverfish co-habiting with ants affects several components of their feeding ecology. We combined stable isotope profiling, feeding assays, phylogenetic reconstruction, and microbial community characterization of the Neoasterolepisma silverfish genus and a wider nicoletiid and lepismatid silverfish panel where divergent myrmecophilous lifestyles are observed.ResultsStable isotope profiling (δ13C and δ15N) showed that the isotopic niches of granivorous Messor ants and Messor-specialized Neoasterolepisma exhibit a remarkable overlap within an ant nest. Trophic experiments and gut dissections further supported that these specialized Neoasterolepisma silverfish transitioned to a diet that includes plant seeds. In contrast, the isotopic niches of generalist Neoasterolepisma silverfish and generalist nicoletiid silverfish were clearly different from their ant hosts within the shared nest environment. The impact of the myrmecophilous lifestyle on feeding ecology was also evident in the internal silverfish microbiome. Compared to generalists, Messor-specialists exhibited a higher bacterial density and a higher proportion of heterofermentative lactic acid bacteria. Moreover, the nest environment explained the infection profile (or the 16S rRNA genotypes) of Weissella bacteria in Messor-specialized silverfish and the ant hosts.ConclusionsTogether, we show that social hosts are important determinants for the feeding ecology of symbiotic animals and can induce diet convergence.

Metabolic engineering of commensal bacteria for gut butyrate delivery and dissection of host-microbe interaction

An overwhelming number of studies have reported the correlation of decreased abundance of butyrate-producing commensals with a wide range of diseases. However, the molecular-level mechanisms whereby gut butyrate causally affects the host mucosal immunity and pathogenesis were poorly understood, hindered by the lack of efficient tools to control intestinal butyrate. Here we engineered a facultative anaerobic commensal bacterium to delivery butyrate at the intestinal mucosal surface, and implemented it to dissect the causal role of gut butyrate in regulating host intestinal homeostasis in a model of murine chronic colitis. Mechanistically, we show that gut butyrate protected against colitis and preserved intestinal mucosal homeostasis through its inhibiting effect on the key pyroptosis executioner gasdermin D (GSDMD) of colonic epithelium, via functioning as an HDAC3 inhibitor. Overall, our work presents a new avenue to build synthetic living delivery bacteria to decode causal molecules at the host-microbe interface with molecular-level insights.

Enhancing microbial diversity as well as multi-organ health in hind-limb unloaded mice

During space travel, the gut microbiota is changed which can lead to health-related issues. Previously, we utilized the hind-limb unloaded (HU) mouse, which is an established ground-based in-vivo model of microgravity and observed altered gut microbiota. In this study, we evaluated the beneficial effects of novel bacterial conditioned media in HU mice to understand if they can offset the effects of unloading in the HU mouse model. We aimed to explore the influence of bacterial conditioned media on diversity and quantity of intestinal microbes in HU mice, and investigated the microarchitecture of mice retinas and kidneys to evaluate the potential systemic effects of bacterial conditioned media in HU mice. Four-month-old, male C57/Bl6 mice were separated into groups: including the ground-based control group, the HU group mice fed with vehicle as placebo (HU-placebo mice), and the HU group fed with bacterial conditioned media (HU-CP mice) and kept under controlled environmental conditions for three weeks. Next, mice were sacrificed; gut dissections were conducted, and metagenomic analysis of bacterial species was performed via DNA extraction and 16S rRNA analysis. The results revealed an HU-induced reduction in intestinal microbial diversity, and an increase in pathogenic bacteria dominated by Firmicutes (45%). In contrast, supplementation with bacterial conditioned media for three weeks led to a significant increase in gut microbial diversity with noticeable changes in the OTUs abundance in the HU mice. Additionally, HU-induced muscle weakness and structural abnormalities in the retina and kidney were partially prevented with bacterial conditioned media. Moreover, a greater diversity of several bacteria in the HU-CP was observed including, Bacteriodota, Firmicutes, Proteobacteria, Actionobacteriota, Verrucomicorbiota, Cyanobacteria, Gemmatimonadota, Acidobacteriota, Chloroflexi, Myxococcota, and others. Prospective research involving molecular mechanistic studies are needed to comprehend the systemic effects of bacterial metabolites conditioned media on experimental animal models under chronic stress.

Effect of Microgravity on the Gut Microbiota Bacterial Composition in a Hindlimb Unloading Model.

We utilised a ground-based microgravity hindlimb unloading (HU) mouse model to elucidate the gut microbiota bacterial changes in mice under a simulated microgravity environment. Four-month-old, male C57/Bl6 mice were randomly divided into ground-based controls and the HU groups and kept under controlled environmental conditions. For the microgravity environment, the mice were suspended in special cages individually for 20 days. At the end of the suspension, the mice were sacrificed; gut dissections were performed, followed by a metagenomic analysis of bacterial species, which was carried out by extracting DNA and 16S rRNA analysis. The results revealed that the gut bacterial communities of mice under gravity and microgravity were different. Notably, our findings revealed differences in the bacterial community structure. Around 449 bacterial OTUs were specific to mice kept under normal gravity versus 443 bacterial OTUs under microgravity conditions. In contrast, 694 bacterial OTUs were common to both groups. When the relative abundance of taxa was analyzed, Bacteroidetes dominated the gut (64.7%) of normal mice. Conversely, mice in the microgravity environment were dominated by Firmicutes (42.7%), and the relative abundance of Bacteroidetes differed significantly between the two groups (p < 0.05). The distribution of Muribaculaceae between normal mice versus microgravity mice was significantly different, at 62% and 36.4%, respectively (p < 0.05). Furthermore, a significant decrease in 11 bacteria was observed in mice under simulated microgravity, including Akkermansia muciniphila, Eubacterium coprostanoligenes, Bacteroides acidifaciens, Clostridium leptum, Methylorubrum extorquens, Comamonas testosterone, Desulfovibrio fairfieldensis, Bacteroides coprocola, Aerococcus urinaeequi, Helicobacter hepaticus, and Burkholderiales. Further studies are needed to elucidate gut bacterial metabolites of these identified bacterial species in microgravity conditions and normal environment. Notably, the influence of these metabolites on obesity, neuroprotection, musculoskeletal and cardiovascular dysfunction, longevity, inflammation, health, and disease in astronauts ought to be investigated and will be important in developing procedures against adverse effects in astronauts following space travel.

Adapting Museum Workflows to Accommodate Omic-based, Multi-species Occurrences from Environmental Samples

Natural history museums play a critical role in curating global anthropological, biological and geological diversity. Museums host more than voucher samples for comparative identification purposes. They host a suite of derived products and associated information, which cascade from these records of diversity in time and space. Increasingly, museums capture whole communities through curation of environmental samples and their derived data. Environmental samples are defined as material samples that yield multi-species occurrence records that cannot be sorted into traditional independent lots and whose membership can only be determined by downstream analytical processes, usually based on the generation of DNA sequence profiles. These materials include samples such as filtered water; feces, gut dissections or gastric lavage; scraped and blended settlement plates; as well as sediment, ice or soil cores. Given the level of ongoing and predicted global change, through the curation of these environmental samples, museums provide time capsules of diversity and longitudinal breadth to examine temporal patterns in phenology, range shifts, species interactions and diversity loss or gain. The future of natural history museums is likely to expand from providing inventory-like services to more observatory functions. They should provide strategic windows to the past by partnering with place-based observatories or targeted regions of predicted change. Rather than individual specimens, environmental samples represent entire systems as events, defined by space and time. Thus, these environmental samples are explicitly event-centric. The cascade of derived information, protocols and handling steps, as well as analytical processes and their associated metadata, needs to be tracked via the minting of persistent identifiers at each material sample and derived data step. Efforts are underway through collaboratively funded programs like the iSamples Cyberinfrastructure group, funded by the US National Science Foundation, to semantically map these various material samples while capturing their parent-child relationships. Moreover, museums, such as the Smithsonian’s National Museum of Natural History, are scoping and examining existing systems of record, metadata models and mapping workflows, with particular emphasis on environmental samples. These event-based samples create new challenges for historically taxonomically-siloed departments pertaining to custodianship, permitting, versioning of biodiversity occurrence records based on improved reference libraries, and future use and reuse of these material samples. Management systems are being augmented or adopted to encompass these new workflows to ensure that today’s samples can support tomorrow’s science in service to a sustainable future.

Experimental methods modestly impact interpretation of the effect of environmental exposures on the larval zebrafish gut microbiome

Rapidly growing fields, such as microbiome science, often lack standardization of procedures across research groups. This is especially the case for microbiome investigations in the zebrafish (Danio rerio) model system, which is quickly becoming a workhorse system for understanding the exposure-microbiome-physiology axis. To guide future investigations using this model system, we defined how various experimental decisions affect the outcomes of studies on the effects of exogenous exposure on the zebrafish gut microbiome. Using a model toxicant, benzo[a]pyrene (BaP), we assessed how each of two dissection methods (gut dissection vs. whole fish), three DNA extraction kits (Qiagen Blood & Tissue, Macherey–Nagel NucleoSpin, and Qiagen PowerSoil), and inclusion of PCR replicates (single vs. pooled triplicate reactions) affected our interpretation of how exposure influences the diversity and composition of the gut microbiome, as well as our ability to identify microbiome biomarkers of exposure. We found that inclusion of PCR replicates had the smallest effect on our final interpretations, and the effects of dissection method and DNA extraction kit had significant effects in specific contexts, primarily in the cases of identifying microbial biomarkers.

The Role of 4-Phenylbutyric Acid in Gut Microbial Dysbiosis in a Mouse Model of Simulated Microgravity

The altered gut microbes of astronauts during space travel may contribute to health issues after their return to Earth. Previously, an association between the elevated endoplasmic reticulum (ER) stress and gut microbial dysbiosis has been described. Herein, we induced gut microbial changes in mice under a simulated microgravity environment in an established model of hindlimb unloaded (HU) mice. The intestinal metabolomic profiles under microgravity conditions using the HU model were examined, along with the potential role of 4-phenylbutyric acid (4-PBA), a potent ER stress inhibitor. For a microgravity environment, the mice were suspended in special cages individually for three weeks. Mice were sacrificed, and gut dissections were performed, followed by amplicon sequencing analysis of bacterial species via DNA extraction and 16S rRNA analysis. The results indicate that the gut bacterial communities of mice differed under gravity and microgravity conditions. Principal component analyses revealed differences in the bacterial community structure in all groups. Around 434 operational taxonomic units (OTUs) were specific to mice seen in controls, while 620 OTUs were specific to HU mice. Additionally, 321 bacterial OTUs were specific to HU mice treated with 4-PBA. When the relative abundance of taxa was analyzed, Bacteroidetes dominated the gut of control and HU mice treated with 4-PBA.. In contrast, the untreated HU mice were dominated by Firmicutes. At the genus level, a reduction in beneficial species of Akkermansia and Lactobacillus was observed in HU but not the unloaded–treated and control mice. Furthermore, an increase in the relative abundance of Lachnospiraceae and Enterorhabdus, associated with inflammation, was observed in HUmice but not in controls and unloaded-treated mice. Following treatment with 4-PBA, the ratio of Firmicutes to Bacteroidetes was restored in unloaded–treated mice, comparable to controls. Of note, beneficial microbes such as Akkermansia and Lactobacillus were observed in unloaded–treated mice but not or in lesser relative abundance in HU mice. Nonetheless, microbial diversity was reduced in unloaded–treated mice compared to controls, and future studies are needed to mitigate this finding. These may comprise the addition of pre-/pro- and postbiotic species in the diet to increase microbial diversity. Overall, the findings suggest that 4-PBA, a potent ER stress inhibitor, may have therapeutic value in treating patients on prolonged bed rest or astronauts during spaceflight.

The transmission of visceral leishmaniasis in the municipality of Guarujá, on the Coast of São Paulo state, Brazil

OBJECTIVE: To perform an entomological survey, evaluating the circulation of Leishmania spp. in sand flies captured from the new foci of visceral leishmaniasis (VL) in the coastal region of São Paulo state. METHODS: Sand flies were captured from November 2016 to September 2018 using light traps of the Centers for Disease Control (CDC), in the neighborhood where VL cases were reported. Leishmania spp. circulation was evaluated by gut dissection and molecular analysis of the females captured. RESULTS: Nyssomyia intermedia was the more frequent species (90,7%) within the 1,203 sand flies captured. We found no flagellates in dissected females, but two pools containing females of Ny. Intermedia presented DNA of L. infantum. CONCLUSION: Our results suggest that Ny. intermedia might be involved in the establishment of this new VL focus in Sao Paulo. However, before incriminating this species as a L. infantum vector, further studies should investigate other vectorial capacity parameters, including competence, survival, and feeding habits.

The transmission of visceral leishmaniasis in the municipality of Guarujá, on the Coast of São Paulo state, Brazil.

ABSTRACTOBJECTIVE To perform an entomological survey, evaluating the circulation of Leishmania spp. in sand flies captured from the new foci of visceral leishmaniasis (VL) in the coastal region of São Paulo state.METHODS Sand flies were captured from November 2016 to September 2018 using light traps of the Centers for Disease Control (CDC), in the neighborhood where VL cases were reported. Leishmania spp. circulation was evaluated by gut dissection and molecular analysis of the females captured.RESULTSNyssomyia intermedia was the more frequent species (90,7%) within the 1,203 sand flies captured. We found no flagellates in dissected females, but two pools containing females of Ny. intermedia presented DNA of L. infantum.CONCLUSION Our results suggest that Ny. intermedia might be involved in the establishment of this new VL focus in Sao Paulo. However, before incriminating this species as a L. infantum vector, further studies should investigate other vectorial capacity parameters, including competence, survival, and feeding habits.

Trypanosomes of the Trypanosoma theileri Group: Phylogeny and New Potential Vectors

Trypanosomes belonging to Trypanosoma theileri group are mammalian blood parasites with keds and horse fly vectors. Our aim is to study to vector specificity of T. theileri trypanosomes. During our bloodsucking Diptera survey, we found a surprisingly high prevalence of T. theileri trypanosomes in mosquitoes (154/4051). Using PCR and gut dissections, we detected trypanosomes of T. theileri group mainly in Aedes mosquitoes, with the highest prevalence in Ae. excrucians (22%), Ae. punctor (21%), and Ae. cantans/annulipes (10%). Moreover, T. theileri group were found in keds and blackflies, which were reported as potential vectors for the first time. The vectorial capacity was confirmed by experimental infections of Ae. aegypti using our isolates from mosquitoes; sand fly Phlebotomus perniciosus supported the development of trypanosomes as well. Infection rates were high in both vectors (47–91% in mosquitoes, 65% in sandflies). Furthermore, metacyclic stages of T. theileri trypanosomes were observed in the gut of infected vectors; these putative infectious forms were found in the urine of Ae. aegypti after a second bloodmeal. On the contrary, Culex pipiens quinquefasciatus was refractory to experimental infections. According to a phylogenetic analysis of the 18S rRNA gene, our trypanosomes belong into three lineages, TthI, ThII, and a lineage referred to as here a putative lineage TthIII. The TthI lineage is transmitted by Brachycera, while TthII and ThIII include trypanosomes from Nematocera. In conclusion, we show that T. theileri trypanosomes have a wide range of potential dipteran vectors, and mosquitoes and, possibly, sandflies serve as important vectors.

Pollen feeding by syrphids varies across seasons in a Mediterranean landscape dominated by the olive orchard

Syrphids provide valuable ecosystem services such as pollination, pest control or organic matter decomposition. In many cases, adults exploit pollen resources from the landscape to complete their life cycles. Yet, the knowledge about the most suitable plants for enhancing syrphid populations is still insufficient for most habitats. Also syrphid distribution across the landscape is understudied. In this work we analyzed: (i) syrphids distribution across different land uses and seasons in a Mediterranean landscape dominated by olive orchards, (ii) pollen resources exploited by the most abundant syrphid species and (iii) specific pollen resources relevant for egg production. Syrphids were captured weekly in spring, summer and autumn from April to November 2013 with a sweep net in patches with different land uses (olive orchards, herbaceous and scrubland patches). Nine species, generally with predatory aphidophagous larvae, were identified. The most abundant species was Sphaerophoria scripta (L.) followed by Melanostoma mellinum (L.). Sphaerophoria scripta was associated to olive orchards while M. mellinum was associated to herbaceous/scrubland patches. Pollen selection and consumption and number of eggs within gravid females for the most abundant species were determined through gut dissection and identified with a microscope. Several pollen types were showed a positive selection index by syrphid species. During spring and summer, the most ingested pollen types belonged to abundant plants in the patches of capture indicating that syrphids possibly do not need to fly among patches to feed during those periods. In spring, Asteraceae and Plantago type were particularly consumed by S. scripta and M. mellinum gravid females respectively while in summer feeding habits of males, gravid and non-gravid females did not differ. Females consumed more pollen than males but the number of eggs in gravid females was not related with the amount of ingested pollen grains. This study brings some insights about the seasonal variation of pollen feeding habits shown by adult syrphids across a Mediterranean heterogeneous landscape dominated by the olive orchard. In spring, dense flowering strips maintained within the olive orchards might attract and nourish adult syrphids while in summer syrphids might fly to non-crop areas to feed.

An integrative approach combining molecular analyses and experiments to investigate predation of insect eggs by a mite

AbstractUncovering the predation habits of small arthropods such as mites can be a major challenge, as direct observations are not always feasible in natura. Therefore, PCR‐based analyses of gut content, or body content when gut dissection is not applicable, are being increasingly used to detect remains of prey items. Here, we present an integrative approach to investigate predation of eggs of the viburnum leaf beetle Pyrrhalta viburni, an invasive pest in North America, by the oribatid mite species Trichoribates trimaculatus, to assess the potential of this mite as a biological control agent. We combined (1) manipulative laboratory experiments exposing beetle eggs to mites under controlled conditions and (2) body content molecular analyses using quantitative PCR (qPCR) to detect traces of consumed P. viburni egg DNA in mites. To account for risks of false‐negative and false‐positive results, mainly due to detectability problems, body surface contamination, and non‐specific DNA amplification, we developed a stepwise procedure to analyze qPCR results. Egg integrity and survivorship were unaffected by mites in all experiments. However, traces of P. viburni DNA were detected in the body of mites exposed to P. viburni eggs, suggesting that they consumed either fragments of the chorion or fragments of the egg cap secreted by P. viburni females to protect the eggs, which was shown to contain P. viburni DNA. In conclusion, T. trimaculatus does not directly impact P. viburni eggs and should therefore not be considered as a biocontrol agent. The fact that mites did not directly predate eggs but contained traces of P. viburni DNA shows that detection of an organism's DNA within a presumed predator does not necessarily equal predation and that results of molecular analyses should be interpreted with caution in studies attempting to reconstruct trophic interactions.

Comparative study of biology on ground beetles (Coleoptera: Carabidae) - flight ability, feeding habits and fecundity

We studied flight ability, feeding habits and fecundity in carabids. Based on these traits, we investigated characteristics of five species of Harpalus, Synuchus and Carabus as bioindicators of changing environments. Three species of Harpalus, H. griseus, H. eous and H. tridens, showed different degrees of flight ability. We examined the morphology and the length of hind wings, and also investigated by dissection the phenology of flight muscles. The ratio of hind wing to body length (HWBL) was 0.93 in H. tridens, 0.99 in H. eous and 1.02 in H. griseus. The aerial catches ratio to total catches (aerial / aerial+ pitfall traps) of H. tridens was lower (16%) than the other two (72, 76%), and the proportion of individuals with flight muscles of H. tridens (29%) was lower than the other two (71, 77%), indicating H. tridens has lowest flight ability. All three species exhibited flight muscle polymorphism. The hind wings of Synuchus cycloderus were mono-morphic macropterous with 0.75 (HWBL). However, no individuals were caught by aerial traps, and none possessed the flight muscles, indicating this species does not fly. The hind wings of Carabus procerulus were mono-morphic stick-shaped brachyptery without the flight muscle. Flight is important trait for food searching and dispersal. Gut dissection revealed that three Harpalus species depended mainly on seeds and partly on arthropods. The fact that animal fragments were found more frequently in the guts of H. tridens than the other two indicated a close relationship between flight ability and diet. Through gut dissection, we found S. cycloderus was a generalist predator. It preys not only on larvae but also adults of small arthropods including collembola. The food remains of guts of C. procerulus consisted of amorphous fluid, and cuticles were hardly detected. It suggested that the inside of prey was exclusively consumed by extra-oral digestion rather than chewing. Fecundity was assessed by gonad dissection through the number of ovarian eggs and their size. S. cycloderus had many eggs with small size, by contrast C. procerulus and three Harpalus species had few-large eggs. Many studies have shown that ground beetles responded differently to vegetation disturbances. We interpreted these results from their ecological traits. Our previous study of the vegetation disturbance effects on ground beetles demonstrated that C. procerulus declined in number was accompanied with decline in body size. Food shortage induced the reduction in both number and body size of C. procerulus. On the other hand, the number of S. cycloderus significantly increased. Although some of their prey were reduced, as generalist predators, they alternatively consumed other prey that has increased greatly in number. The trait of S. cycloderus with many eggs has also great potential for population explosion. The numbers of H. griseus and H. eous were not affected by the disturbance, while H. tridens decreased. Shortage of prey organisms caused negative effects on H. tridens compared to H. griseus and H. eous which depend more on seeds. We have been studying ground beetles in Japan, and already have some basic knowledge, such as hind wings, flight ability, feeding habits, reproductive phenology and seasonal activity for 78 key species. Ground beetles are excellent bioindicators. Our bottom up approach by the dissection of ground beetles collected periodically through the year would be essential when we have to face with extreme conditions, such as global warning.

Molecular gut content analysis of different spider body parts.

Molecular gut-content analysis has revolutionized the study of food webs and feeding interactions, allowing the detection of prey DNA within the gut of many organisms. However, successful prey detection is a challenging procedure in which many factors affect every step, starting from the DNA extraction process. Spiders are liquid feeders with branched gut diverticula extending into their legs and throughout the prosoma, thus digestion takes places in different parts of the body and simple gut dissection is not possible. In this study, we investigated differences in prey detectability in DNA extracts from different parts of the spider´s body: legs, prosoma and opisthosoma, using prey-specific PCR and metabarcoding approaches. We performed feeding trials with the woodlouse hunter spider Dysdera verneaui Simon, 1883 (Dysderidae) to estimate the time at which prey DNA is detectable within the predator after feeding. Although we found that all parts of the spider body are suitable for gut-content analysis when using prey-specific PCR approach, results based on metabarcoding suggested the opisthosoma is optimal for detection of predation in spiders because it contained the highest concentration of prey DNA for longer post feeding periods. Other spiders may show different results compared to D. verneaui, but given similarities in the physiology and digestion in different families, it is reasonable to assume this to be common across species and this approach having broad utility across spiders.

Efficacy and toxicity of praziquantel in helminth-infected barbel (Barbus barbus L.).

This study evaluated efficacy and toxicity of the pyrazinoisoquinoline anthelmintic praziquantel (PZQ) in barbel infected with metacercariae of Diplostomum spathaceum and adult Pomphorhynchus laevis, and assessed antioxidant biomarkers and the lipid peroxidation response in juvenile barbel post-treatment. The estimated 96-hr LC50 of PZQ was 28.6mg/L. For evaluation of efficacy, barbel naturally infected with D.spathaceum were exposed to a 10 and 20mg/L PZQ 4-day bath treatment. Both concentrations were 100% effective against D.spathaceum and significantly (p<.01) affected the activity of catalase, superoxide dismutase, glutathione reductase and glutathione-S-transferase as well as levels of reduced glutathione in liver and muscle. The efficacy of orally administered PZQ was assessed in adult barbel naturally infected with P.laevis. Fish were administered 10, 30 and 50mg/kg of body weight and examined via gut dissection after 6days. The 50mg/kg dose significantly decreased the intensity of infection. Praziquantel is a feasible bath treatment for barbel infected with D.spathaceum and has potential for oral treatment of broodfish infected with P.laevis.

Wild flower resources and insect honeydew are potential food items for Elasmus flabellatus

Adult parasitoids need non-host food such as nectar or honeydew for survival and reproduction. In a conservation biological control strategy, the knowledge about non-host feeding of parasitoid species is a key factor to successfully increase their action. The nutritional behavior of Elasmus flabellatus (Fonscolombe) (Hymenoptera: Eulophidae), a major parasitoid of the olive moth, Prays oleae (Bernard) (Lepidoptera: Praydidae), is completely unknown. Survival experiments were performed on two secondary olive pest honeydews and eight common flowering plant species in order to analyze their suitability as potential food sources for E. flabellatus females. Abdomen and gut dissections were carried out to verify the pollen consumption and the egg production. Floral architecture and insect morphology were described. Cox’s proportional hazard regression models were used to analyze the differences between parasitoid survivals. Honeydews secreted by Saissetia oleae (Olivier) (Hemiptera: Coccidae) and Euphyllura olivina (Costa) (Hemiptera: Psyllidae) resulted in the best performance followed by the flowers of Malva sylvestris L. (Malvaceae), Daucus carota L. (Apiaceae), and the Cichorioideae Tolpis barbata (L.) and Andryala integrifolia L. Theoretical flower resources accessibility were assessed and related with the survival results. E. flabellatus females did not consume pollen and did not produce eggs, suggesting that the species is synovigenic and requires additional foods for egg production. In sustainable pest control programs, this novel knowledge is a promising opportunity for improving suitable food resources of E. flabellatus in the field.

Temperature and water flow influence feeding behavior and success in the barnacle Balanus glandula

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 507:207-218 (2014) - DOI: https://doi.org/10.3354/meps10848 Temperature and water flow influence feeding behavior and success in the barnacle Balanus glandula Michael T. Nishizaki1,2,*, Emily Carrington1,2 1Department of Biology, University of Washington, Seattle, WA 98195, USA 2Friday Harbor Laboratories, Friday Harbor, WA 98250, USA *Corresponding author: mnishiza@uoguelph.ca ABSTRACT: Suspension feeding is a common energy acquisition strategy for many marine organisms. Conditions in the fluid environment (e.g. flow, temperature) can influence both the flux of particles past an organism and the efficiency with which organisms retain those particles. We investigated feeding behavior in the barnacle Balanus glandula under a range of water velocities and temperatures using gut dissections to directly quantify capture rates of food particles. Overall, the percentage of barnacles observed beating was typically high (68 ± 3%), yet gut dissections confirmed that a far lower percentage had actually ingested food particles (hydrated Artemia cysts; 22 ± 3%). This discrepancy suggests that cirral activity may serve other functions and that simple behavioral descriptions provide a poor proxy for barnacle feeding rate. Although the delivery of cysts to the cirral net and cyst capture rates peaked at intermediate water velocities (7.5 to 20 cm s-1), capture efficiency (the ratio of cysts captured to cysts encountered) was highest under the slowest flow (1 cm s-1). Model analysis demonstrated that detailed characterization of cirral beating behavior is required to accurately predict patterns of flow-dependent cyst capture. Barnacles also showed a clear thermal optimum between 10 and 15°C in both capture rate and efficiency. At high temperatures (25°C), feeding was reduced due to an increase in abbreviated beating behavior, whereas at low temperatures (5°C) reduced capture was likely a consequence of slower beating rate. Again, only when beating behavior was incorporated into models were patterns of temperature-dependent cyst capture accurately predicted. These results suggest that the limits to feeding success are not simply biophysical, but also behavioral in nature. KEY WORDS: Suspension feeding · Barnacles · Water flow · Thermal tolerance Full text in pdf format PreviousNextCite this article as: Nishizaki MT, Carrington E (2014) Temperature and water flow influence feeding behavior and success in the barnacle Balanus glandula. Mar Ecol Prog Ser 507:207-218. https://doi.org/10.3354/meps10848 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 507. Online publication date: July 17, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.

Adaptations for Symbiont-Mediated External Digestion in Sirex noctilio (Hymenoptera: Siricidae)

Abstract Wood-feeding insects face a host of physical, chemical, and nutritional barriers in their food resource. Wood-boring Hymenoptera in the family Siricidae are associated with mutualistic basidiomycete wood-rot fungi, which assist colonization and provide nutrition for their insect partner, though functional properties of this symbiosis are poorly described. In this study, we document the behavioral and morphological adaptations of the globally invasive woodwasp, Sirex noctilio F., for foraging using its fungal symbiont Amylostereum areolatum (Chaillet ex Fries) Boidin. Larvae concentrated foraging near the border of fungal symbiont growth in pine xylem. Foraging larvae do not ingest bulk xylem tissue, but rather use specialized asymmetric mandibles to press xylem shavings and extract liquid fractions. Fluids drain toward the oral cavity via a sulcus on the occlusal surface of the left mandible. Processed shavings are expelled from the oral cavity without ingestion and passed along the underside of the larvae via peristaltic undulation to the rear of the feeding gallery. Larval midguts lack elaborated chambers typical in insects reliant on microbial fermentation of cellulose, and no xylem tissue was recovered from gut dissections. Larval behavior and functional morphology indicate larval S. noctilio do not ingest xylem, but instead use the fungus as an external gut for digestion of recalcitrant lignocellulosic compounds.