From feeding habits to food webs: exploring the diet of an opportunistic benthic generalist

2020 ◽  
Vol 655 ◽  
pp. 107-121
Author(s):  
AL van der Reis ◽  
AG Jeffs ◽  
SD Lavery

Deep-sea benthic ecosystems are difficult to study, particularly when trying to clarify diet and trophic relationships. New Zealand scampi Metanephrops challengeri are endemic, commercially prized deep-sea lobsters that are bottom trawled. These lobsters are typically the dominant mobile megafaunal species in the deep-sea benthic habitat, and their burrowing behaviour plays an important role in bioturbation of seafloor habitats. DNA metabarcoding was undertaken on the gut contents of 66 scampi from 4 fishery management areas using COI and 18S rRNA markers to better understand their feeding habits and trophic role. Scampi were confirmed to be opportunistic benthic scavengers, with the gut samples containing over 150 species, ranging from small (e.g. alveolates) to large eukaryotes (e.g. fish). The main dietary components consisted of crabs and prawns, but also included macroalgae and fish. Significant differences were found among scampi gut contents when comparing season and geographic region, but not when comparing sex and size. Due to their generalist scavenging nature, scampi play an important role in the deep-sea benthic ecosystems and are natural benthic samplers that are well suited to being used as deep-sea ecosystem/biodiversity monitors.

2021 ◽  
Author(s):  
Christina Lynggaard ◽  
Alejandro Oceguera-Figueroa ◽  
Sebastian Kvist ◽  
M. Thomas P. Gilbert ◽  
Kristine Bohmann

Leeches play important roles in food webs due to their abundance, diversity and feeding habits. Studies using invertebrate-derived DNA (iDNA) extracted from leech gut contents to target vertebrate DNA have focused on the Indo-Pacific region and mainly leveraged the leech family Haemadipsidae, composed of haematophagous terrestrial leeches, while the aquatic haematophagous, liquidosomatophagous and macrophagous counterparts have largely been disregarded. While there is general knowledge regarding the taxonomic groups that leeches prefer to feed on, detailed taxonomic resolution is still missing and therefore, their potential use for monitoring animals is not known. In this study, 116 non-haemadipsid leeches belonging to 12 species and spanning the three feeding habits were collected in Mexico and Canada. We used DNA metabarcoding to investigate their diet and assess their potential use for vertebrate monitoring. We detected vertebrate taxa from five orders including fish, turtles and birds in the diet of the aquatic haematophagous leeches; eight invertebrate orders of annelids, arthropods and molluscs in the liquidosomatophagous leeches; and ten orders of invertebrates belonging to Arthropoda and Annelida, as well as one vertebrate and one parasitic nematode, in the macrophagous leeches. These results show the potential use of iDNA from the gut content of aquatic haematophagous leeches for retrieving vertebrate taxa, and from macrophagous and liquidosomatophagous counterparts for invertebrates. Our study provides information about the dietary range of the freshwater leeches and the non-haemadipsid terrestrial leech and proof-of-concept for the use of non-haemadipsid leeches for animal monitoring, expanding our knowledge of the use of iDNA from leech gut contents to North America.


2013 ◽  
Vol 1 (1) ◽  
pp. 10
Author(s):  
Noar Muda Satyawan ◽  
Shelly Tutupoho ◽  
Yusli Wardiatno ◽  
Makoto Tsuchiya

Erosion rate on corals due to activities of other biota is called bioerosion. The rock-boring urchin, Echinometra mathaei, when it is abundant, plays a significant role in benthic ecosystems, including biological processes like coral erosion. During feeding, E. mathaei erodes calcium carbonate besides grazing on algae living on coral, so it plays an important role in both organic and inorganic carbons in coral reefs. The urchin E. mathaei actively feeds during the night time (nocturnal grazer). Although in Okinawa four types (A-D) of the urchin exist, the research only focused on the types A and B. Type A of E. mathaei produced 0.44951 g feces per day on average while type B produced 0.38030 g feces per day. CaCO3 analysis in feces and gut contents showed bioerosion rate of E. mathaei type A was 0.64492 g/individu/day, and 0.54436 g/individu/day in type B. There were no significant differences in bioerosion impact of E. mathaei type A and B© Laju erosi pada karang yang disebabkan oleh biota, dikenal dengan bioerosi. Bulu babi jenis Echinometra mathaei, ketika melimpah, menjadi sangat berpengaruh terhadap ekosistem bentik termasuk proses biologi seperti erosi karang. Selama aktivitas makan, E. mathaei menggerus kalsium karbonat dalam proporsi yang besar di samping alga yang tumbuh menempel pada karang sehingga memiliki peran penting dalam siklus karbon organik dan anorganik di ekosistem terumbu karang. Bulu babi E. mathaei aktif mencari makan pada malam hari (nocturnal grazer). Meskipun di Okinanawa ada 4 tipe (A-D), pada eksperimen kali ini memfokuskan pada tipe A dan B saja. Tipe A E. mathaei rata-rata memproduksi 0,44951 g feses/hari dan tipe B memproduksi 0,38030 g feses/hari. Berdasarkan analisis CaCO3 yang dilakukan pada feses dan isi lambung, laju bioerosi yang disebabkan oleh E. mathaei tipe A sebesar 0,64492 g/individu/hari sedangkan tipe B sebesar 0,54436 g/individu/hari. Tidak terdapat perbedaan dampak bioerosi yang signifikan antara E. mathaei tipe A dan B©


Author(s):  
Pierre Taberlet ◽  
Aurélie Bonin ◽  
Lucie Zinger ◽  
Eric Coissac

Environmental DNA (eDNA), i.e. DNA released in the environment by any living form, represents a formidable opportunity to gather high-throughput and standard information on the distribution or feeding habits of species. It has therefore great potential for applications in ecology and biodiversity management. However, this research field is fast-moving, involves different areas of expertise and currently lacks standard approaches, which calls for an up-to-date and comprehensive synthesis. Environmental DNA for biodiversity research and monitoring covers current methods based on eDNA, with a particular focus on “eDNA metabarcoding”. Intended for scientists and managers, it provides the background information to allow the design of sound experiments. It revisits all steps necessary to produce high-quality metabarcoding data such as sampling, metabarcode design, optimization of PCR and sequencing protocols, as well as analysis of large sequencing datasets. All these different steps are presented by discussing the potential and current challenges of eDNA-based approaches to infer parameters on biodiversity or ecological processes. The last chapters of this book review how DNA metabarcoding has been used so far to unravel novel patterns of diversity in space and time, to detect particular species, and to answer new ecological questions in various ecosystems and for various organisms. Environmental DNA for biodiversity research and monitoring constitutes an essential reading for all graduate students, researchers and practitioners who do not have a strong background in molecular genetics and who are willing to use eDNA approaches in ecology and biomonitoring.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Alexandra Schoenle ◽  
Manon Hohlfeld ◽  
Karoline Hermanns ◽  
Frédéric Mahé ◽  
Colomban de Vargas ◽  
...  

AbstractHeterotrophic protists (unicellular eukaryotes) form a major link from bacteria and algae to higher trophic levels in the sunlit ocean. Their role on the deep seafloor, however, is only fragmentarily understood, despite their potential key function for global carbon cycling. Using the approach of combined DNA metabarcoding and cultivation-based surveys of 11 deep-sea regions, we show that protist communities, mostly overlooked in current deep-sea foodweb models, are highly specific, locally diverse and have little overlap to pelagic communities. Besides traditionally considered foraminiferans, tiny protists including diplonemids, kinetoplastids and ciliates were genetically highly diverse considerably exceeding the diversity of metazoans. Deep-sea protists, including many parasitic species, represent thus one of the most diverse biodiversity compartments of the Earth system, forming an essential link to metazoans.


Author(s):  
Chiyuki Sassa

The feeding habits of myctophid larvae of Symbolophorus californiensis were examined in the southern transition region of the western North Pacific where the main spawning and nursery grounds of S. californiensis are formed. This species is a key component of the pelagic ecosystems of this region, and their larvae attain one of the largest sizes among myctophids. To analyse gut contents larvae, including most life history stages after yolk-sac absorption (3.7 to 22.2 mm body length (BL)), were collected in the upper 100 m layer in 1997 and 1998. Feeding incidence was higher during the day than at night (53.1–92.3% versus 0–5.6%), and daytime feeding incidence increased gradually with larval growth. Larvae fed mainly on copepods of various developmental stages. Larvae of S. californiensis showed an ontogenetic change in their diet: larvae ≤7.9 mm BL (i.e. preflexion stage) fed mainly on copepod eggs and nauplii, while the larvae ≥8 mm BL consumed mainly calanoid copepodites such as Pseudocalanus and Paracalanus spp. In the largest size-class (16–22.2 mm BL), the furcilia stage of euphausiids was also an important prey item. There was an increase in the average prey size with growth in larvae ≤11.9 mm BL, while the number of prey eaten positively correlated with growth in larvae ≥12 mm BL. The trophic niche breadth also increased with larval growth, which would ensure a wide range of available food resources for the larger size-class larvae.


2006 ◽  
Vol 86 (6) ◽  
pp. 1443-1447 ◽  
Author(s):  
D. Fourgon ◽  
G. Lepoint ◽  
I. Eeckhaut

Analyses of the natural abundance of carbon and nitrogen stable isotopes were performed to investigate the feeding habits of two ophiuroids, Ophiomastix venosa and Ophiocoma scolopendrina, and to assess the potential benefit obtained by the symbiotic Ophiomastix venosa juveniles. A tracer experiment was also carried out to clarify the contribution of algae to the nitrogen uptake amongst the tested ophiuroids. Our results suggest that Ophiocoma scolopendrina adults occupy a higher position in the food web than Ophiomastix venosa and mainly feed on neuston. In contrast, O. venosa adults feed on the alga Sargassum densifolium and on organic matter associated with sediment. Free juveniles and symbiotic juveniles of O. venosa have intermediate δ13C values between both adult species. The high proportion of 13C in the symbiotic juveniles compared to the one in their conspecific adults indicates that their diet slightly differs from the latter and is closer to that of Ophiocoma scolopendrina. This raises the hypothesis that symbiotic juveniles steal neuston from their associated host, O. scolopendrina.


2019 ◽  
Vol 2 ◽  
Author(s):  
Lucija Šerić Jelaska ◽  
Barbara Anđelić ◽  
Mišel Jelić ◽  
Tomislav Kos

A type of management and the use of pesticides in arable land may negatively affect a range of soil biota and thus their food webs important for ecosystem functioning. By analysing trophic interactions we could reveal the extent of potential benefits that certain organisms can provide in biocontrol and maintaining healthy ecosystems. To evaluate the role of predatory arthropods within olive orchards and vineyards under Integrated Pest Management (IPM) and Ecological Pest Management (EPM) we collected carabid beetles together with other dominant predatory arthropods in the field (e.g. ladybugs, antlions, spiders, centipedes) and subdued the individuals to molecular gut content analyses using NGS. DNA metabarcoding diet analysis approach allowed detecting a wide variety of taxa from gut contents of the predators. In addition, using ICP-MS and LC-MS/MS we quantified Cu, pesticides and its residues in soil and animals representing different trophic guilds. Since concentrations of some toxic compounds detected in carabids body were negatively correlated with those in the soil, we aim to identify a potential vector for possible transfer of toxicants to general predators via predation. The results contribute to the risk assessment of proliferation of detected chemical compounds including copper in the ecosystem and to the knowledge on the overall field sustainability of predatory invertebrates to maximize their role in pest control. The study was conducted under the project activity of HRZZ – Mediteratri.


2017 ◽  
Vol 66 (1) ◽  
pp. 136 ◽  
Author(s):  
Yulibey Caleño Ruiz ◽  
Carlos Alberto Rivera Rondon ◽  
Hernando Ovalle

Tropical high mountain lakes show unique environmental conditions where chironomids play an important role in ecosystem functioning. The characteristics of these environments could favor diet overlap and therefore a high interspecific competition. This study described the dietary habits of chironomid genera, identified whether the dietary habits were specialized or generalist, and analyzed the diet overlap in the genera. Chironomidae larvae were collected from four lakes of the Chingaza paramo during the dry season, between April and May of 2 016. The feeding habits of larvae were evaluated by analyzing gut contents following standard methods. Each genus was assigned to trophic guilds (carnivore, detritivore and algivore) and the diet overlap was estimated using the Pinka's index. A total of 1 003 individuals were collected and nine genera were identified. Larvae consumed mainly fine particulate organic matter (FPOM), algae, macrophyte fragments, macroinvertebrates, and animal tissues. FPOM was the main feeding resource of detritivores. The analysis of diets showed a high affinity of each genus for a single trophic guild and most of the genera were generalist in the use of resources. For all lakes, high levels of diet overlap were observed among genera and trophic guilds, mainly among detritivores. Our results suggested that Chironomidae larvae of these lakes presented well differentiated trophic habits, and showed a moderate diet overlap within detritivores and carnivores.


<em>Abstract.</em>—Understanding the diel activity of a species can shed light on potential interactions with other species and inform management practices. To understand the diel activity of Northern Snakehead <em>Channa argus</em>, feeding habits and movement patterns were observed. Two hundred seventy-three Northern Snakehead were captured by boat electrofishing during May and June of 2007 and 2008. Their gut contents were extracted and preserved. The level of digestion of each prey item was estimated from fresh (1) to >50% digested (4) or empty (5). Random forest models were used to predict feeding activity based on time of day, tide level, date, water temperature, fish total length, and sex. Diel movement patterns were assessed by implanting Northern Snakehead with radio transmitters and monitoring them every 1.5 h for 24 h in both March and July 2007. Movement rates were compared between March and July and among four daily time periods. Independent variables accounted for only 6% of the variation in feeding activity; however, temporal feeding patterns were apparent. No fresh items were observed in guts between 12:30 and 7:30 am, and the proportion of empty stomachs increased at the end of May coinciding with the onset of spawning. Overall, fish moved greater distances during the July tracking period compared to March. Fish showed a greater propensity to move during daylight hours than at night during the March tracking period. A similar but nonsignificant (<EM>P </EM>> 0.05) pattern was observed in July. Movement and feeding data both indicated greater activity during daylight hours than at night, suggesting that Northern Snakehead is a diurnal species. Based on our preliminary findings, we hypothesize that a) diurnal species are more susceptible than nocturnal species to predation by Northern Snakehead and b) Northern Snakehead are more likely to compete for food with diurnal than nocturnal predators.


2003 ◽  
Vol 63 (2) ◽  
pp. 269-281 ◽  
Author(s):  
A. L. Henriques-Oliveira ◽  
J. L. Nessimian ◽  
L. F. M. Dorvillé

Chironomids larvae are frequently one of the most abundant and diverse groups of insects in several kinds of aquatic environments. Also, they play a major role in the aquatic food webs, representing a major link among producers and secondary consumers. This work investigates the feeding behavior of the chironomid larvae present in the Rio da Fazenda, situated in the Parque Nacional da Tijuca, Rio de Janeiro, Brazil, between August 1994 and May 1995. Algae, fungi, pollen, leaf and wood fragments, animal remains, detritus and silt were the main gut contents found in the larvae studied. The main food item ingested by the larvae was detritus, except for the Stenochironomus whose main food source was leaf and wood fragments. Tanypodinae exhibited a large quantity of animal remains of several kinds in the diet. During the period studied it was observed that the diet of 16 genera (out of 24 studied) varied. Tanypodinae had mainly coarse particulate organic matter (> 1 mm) in the gut contents, while Chironominae and Orthocladiinae had fine particulate organic matter (< 1 mm).


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