First Record of Oleacina cyanozoaria (Gundlach in Pfeiffer, 1857) Feeding on a Eleutherodactylus Frog in Pico San Juan, Cumanayagua, Cienfuegos Province, Cuba

Around twenty species of the landsnail subfamily Oleacininae inhabit Cuba. However, only five species were found in south-central region of the island. Despite the frequency of Oleacina in Cuba, these species have been poorly studied and little is known about their ecology, ethology and carnivorous feeding preferences. This field study is the first record showing Oleacina cyanozoaria to be an active predator on a small Eleutherodactylus frog. Small vertebrates have not been previously noted to be part of these voracious species’ diet.

Swarm-mediated phage transport disrupts a biofilm inherently protected from phage penetration

Phage therapy is the treatment of chronic bacterial infections by virus that kill bacteria and it has shown promise in combating antimicrobial resistance (AMR). A typical phage particle is around 100 times bigger than a typical antibiotic molecule. Due to larger size, a phage particle diffuses slower than an antibiotic molecule, and can get trapped in the polymeric mesh of biofilm matrix. We report that a swarm of Capnocytophaga gingivalis, a bacterium abundant in the human oral microbiota, can actively transport phages over long distances. By tracking fluorescently labeled lambda phage particles that do not infect C. gingivalis, we demonstrate active predator transport by a C. gingivalis swarm. As a result, the rate of disruption of the prey i.e., an Escherichia coli colony increases 10 times. Production of curli fiber by a mature E. coli biofilm blocks the intercellular space and is known to inhibit the diffusion of phages within a biofilm. We find that C. gingivalis forms tunnels within the prey biofilm. When phages are actively delivered, curli fiber containing E. coli biofilms are no longer protected against phage infection. Our results demonstrate that active delivery of the predator by a self-propelled swarm might improve the pharmacokinetics of phage therapy. This can lead to the development of a tool to combat chronic AMR biofilms.

Field observations on the behavioural ecology of the stout bobtail squid Rossia macrosoma (Cephalopoda: Sepiolidae) from Scottish waters

Bobtail squids (Cephalopoda: Sepiolidae) are emerging model organisms for a wide range of genetic, anatomical, neurophysiological and behavioural studies. However, the knowledge about their behavioural ecology is scarce and derives mainly from laboratory-based studies, whereas observations from the wild are rare. Here, we use photo and video footage collected through the Cephalopod Citizen Science Project to describe the hunting, burying, mating and spawning behaviour of the stout bobtail squid Rossia macrosoma (Delle Chiaje, 1830) from Scottish waters. Based on our long-term observations, we were able to determine a spawning period from August to November based on different behavioural traits for this species. Furthermore, we observed R. macrosoma to be able to adhere a sand grain layer (‘sand coat’) to its dorsal mantle. This behavioural feature has only been reported for two genera of the sepiolid subfamily Sepiolinae so far, and therefore represents the first of this kind for the subfamily Rossiinae. Lastly, we identified a local sea urchin species as an active predator of egg batches of R. macrosoma and discussed the cryptic egg laying behaviour of this bobtail squid species in terms of its protective traits to avoid egg predation.

New data regarding ecology of freshwater pelagic amphipod Macrohectopus branickii and other crustaceans of plankton from the southern part of Lake Baikal

In this study, we present a list of crustaceans traced in plankton of the southern basin Lake Baikal in addition to some details regarding ecological peculiarities of the only known freshwater pelagic amphipod Macrohectopus branickii. The amphipod is an active predator among major parts of the Lake Baikal food chain. Its role in the lake’s ecosystem is similar to that of Antarctic krill and mysids in Europe and North America water bodies. As an active swimmer, M. branickii performs daily vertical migrations. Besides, the species also has horizontal migrations and migrating swarms, including time during breeding period, that hamper species studies. We were interested in clarify some features of the species ecology. As a material we used samples obtained in the 0 to 250 m water layer with a plankton Juday net every 7 to 10 days from 2013 until 2018 as a part of long-term ecological monitoring project of Lake Baikal pelagial. Sampling was conducted in the southern part of the lake off the shore of Bolshie Koty Village. The results showed the presence of one peak of young during breeding period, which is at its maximum in May. The maximum of the 1 to 6 mm group containing young individuals and males occurs in July, and during the same period, a slight increase in immature females in comparison with the first group can also be seen. This finding might be directly linked to the warming trend in Lake Baikal.

New Insectotoxin from Tibellus Oblongus Spider Venom Presents Novel Adaptation of ICK Fold

The Tibellus oblongus spider is an active predator that does not spin webs and remains poorly investigated in terms of venom composition. Here, we present a new toxin, named Tbo-IT2, predicted by cDNA analysis of venom glands transcriptome. The presence of Tbo-IT2 in the venom was confirmed by proteomic analyses using the LC-MS and MS/MS techniques. The distinctive features of Tbo-IT2 are the low similarity of primary structure with known animal toxins and the unusual motif of 10 cysteine residues distribution. Recombinant Tbo-IT2 (rTbo-IT2), produced in E. coli using the thioredoxin fusion protein strategy, was structurally and functionally studied. rTbo-IT2 showed insecticidal activity on larvae of the housefly Musca domestica (LD100 200 μg/g) and no activity on the panel of expressed neuronal receptors and ion channels. The spatial structure of the peptide was determined in a water solution by NMR spectroscopy. The Tbo-IT2 structure is a new example of evolutionary adaptation of a well-known inhibitor cystine knot (ICK) fold to 5 disulfide bonds configuration, which determines additional conformational stability and gives opportunities for insectotoxicity and probably some other interesting features.

Food Composition of the Unisexual Lizard, Darevskia unisexualis (Darevsky, 1966) from Northeastern Anatolia, Turkey

The study presents data on the food composition of the Unisexual Lizard, Darevskia unisexualis (Darevsky, 1966), from Hanak, Ardahan, Turkey. A total of 172 preys were determined in the digestive systems of 44 individuals examined in the study. Insecta, Aranea, Malacostraca, and Gastropoda constitute food composition of lizards. Major prey groups in the food composition are included in Hymenoptera (46.5%), Coleoptera (13.4%), Diptera (8.1%), Lepidoptera (7.6%), Orthoptera (7%) and Hemiptera (7%) in number, whereas Hymenoptera (70%), Lepidoptera (25%), Coleoptera (23%), and Diptera (20%) in frequency. Our result confirm that the Unisexual Lizard is an insectivorous and active predator and generally feed with poor flying or non-flying invertebrates.

Active anti-predator behaviour of red titi monkeys (Plecturocebus cupreus)

Due to their inconspicuous behaviour and colouration, it has been assumed that titi monkeys' main anti-predator behaviour is passive crypsis and hiding. So far, active predator mobbing has been documented only for black-fronted titi monkeys, Callicebus nigrifrons. Here we report for the first time mobbing behaviour of red titi monkeys, Plecturocebus cupreus (previously Callicebus cupreus), as reaction to an ocelot (Leopardus pardalis) and a Boa constrictor. We also report other active anti-predator behaviours, such as alarm calling and approaching, as reactions to tayras (Eira barbara) and raptors. Our observations provide additional evidence for sex differences in anti-predator behaviour, possibly related to the evolution and maintenance of social monogamy.

Fish larvae as food item of planktonic predator (Chaetognatha)

Photos of predation of sagitta (Chaetognatha) to fish larvae are presented for the first time for the Black Sea. While analyzing ichthyoplankton samples obtained in May and November in 2017 (94ᵗʰ and 98ᵗʰ cruises of RV “Professor Vodyanitsky”) several sagittas were found with their guts containing fish larvae. Fish larvae seem to have been captured by sagittas in the same way as sagittas in cannibalism cases, with both folding in half at the spot of capture. The data obtained allow us to assume sagittas in conditions of high abundance of eggs and fish larvae in the plankton to be not only a food competitor of larvae and juveniles of fish, as a fodder plankton consumer, but an active predator, being able to play a significant role in the elimination of ichthyoplankton.