The reconciliation behavior of golden monkeys (Rhinopithecus roxellanae roxellanae) in small breeding groups

Observations were made following 130 spontaneous aggressive incidents in two small breeding groups of captive golden monkeys (Rhinopithecus roxellanae roxellanae). Participants were observed both during the first 10 min following these incidents and during matched control observations. An increased contact rate was observed between opponents following the aggressive incident. Post-conflict contacts were characterized by a number of behavior patterns: open mouth, rapid grooming, embrace, and crouching. Adult males played an important role as mediator in agonistic disputes among females: males intervened in 93.6% of female fights. It is speculated that this intervention behavior is related to the species' organization into one-male units.     

Size of prey ingested by whitefish,Coregonus sp., larvae. Are Coregonus larvae gape-limited predators?

The feeding ecology of whitefish, Coregonus , larvae in oligotrophic Lake Sarnen and eutrophic Lake Hallwil is presented, taking into consideration the size of the prey ingested in relation to the mouth size of larvae and to the availability of zooplankton.
When larvae grow from 10 to 16 mm their mouth width increases from 500 to 1000 μm while their gape height, with the mouth open at 45 and 90°, increases from 200 to 400 μm and from 400 to 700 μm, respectively, whichever lake is considered.
The differences found in the mean prey width between the two lakes arise in part from the composition of diets, and in part from differences in size of the available prey organisms. Whatever the origin of the larvae and the taxon we consider, larvae seem to ingest the most abundant prey size without selecting the biggest ones available even if, from a mechanical point of view, they would be able to ingest them.
Taking into account the generally low density of zooplankton in the uppermost layer of the lake, we conclude that whitefish larvae eat in the manner such as to decrease the cost of prey capture, in terms of energy and time, by choosing the more abundant prey available.     

Efficient use of lactose for the lac promotercontrolled overexpression of the main antigenic protein of the foot and mouth disease virus in Escherichia coli under fed-batch fermentation conditions

Abstract: Derivatives of the lac promoter (tac, pac, rac) belong to the strongest bacterial promoters which are frequently used for the induced overexpression of foreign genes in Escherichia coli . However, their use in fermentation processes is strongly restricted because of the high cost of the inducer iso-propyl-β-D-thiogalactopyranoside (IPTG). The aim of this work was to investigate the possibility of using lac-derived promoters in high cell density processes resulting in a high yield of the induced recombinant protein if glucose is the main carbon and energy source. Lactose is tested as inducer of the main antigenic coat protein (VP1) of the foot and mouth disease (FMD) virus in a T7-RNA polymerase expression system. It was shown that lactose is able to induce the expression of the recombinant gene to an amount of the VP1 protein corresponding to 20% of the total cell protein.     

Structure of the mouth tube of a parasitic copepod,Isobranchia appendiculata Heegaard, 1947 (Siphonostomatoida:Lernaeopodidae)

The structure and musculature of the mouth tube of the lernaeopodidIsobranchia appendiculata Heegaard is described in detail. Situated on the median eminence, the mouth tube appears to be lodged inside a median longitudinal groove on the ventral wall of the cephalothorax. The components of the mouth tube, the labrum and the labium are loosely held together along their lateral edges. The thin, transparent walls of both the labrum and the labium are reinforced by chitinous rods. The musculature of the mouth tube consists of two pairs ofretractores oris, four pairs ofcompressores labri and two pairs oflevatores labii. The mandibles are operated by a pair of antagonistic muscles, theroto adductor mandibulae androto abductor mandibulae. Like other lernaeopodids,I. appendiculata resorts to a browsing type of feeding.     

Ontogenetic structure and distribution patterns of ichthyoplankton in the confluence zone of two river systems in the Eastern Amazon

The ontogenetic structure and longitudinal variability of ichthyoplankton in a confluence zone of two river systems in the Eastern Amazon were evaluated between December 2018 and April 2019, at the time 137 eggs and 7,687 larvae of fish were captured. Ichthyoplankton proved to be heterogeneous between sections of rivers with differences in the number of taxa and abundance. The assemblages were distinguished by a NMDS Analysis, a ANOSIM, a SIMPER and a CCA, they presented a spatial zonation pattern with strong distinction and variability in the composition of the species between the river systems, under strong influence of limnological variables. The assemblages were mainly represented by larvae of Clupeiformes and Perciformes in the clear waters of the Tapajós river and Characiformes and Siluriforms in the cloudy waters of the Amazon river, influenced by the existence of a limnological gradient. Larvae in more advanced development stages were predominant in the Tapajós river while early stages were dominant in the Amazon river. The confluence zone does not seem to be a spawning area, but it is an important transport site for the larvae to reach the nursery areas in the lower stretch of the Amazon river. The encounter of these two river systems seems to guarantee the survival and biological recruitment of several fish species.     

Subtidal macrozoobenthic community resilience to change following natural mouth breaching of the temporarily open/closed East Kleinemonde Estuary,South Africa

The East Kleinemonde Estuary, on the south-east coast of South Africa, typically opens for only short periods, usually <10 days. During a nine-month study in 2006, marine influence persisted for a near-continuous period of three months. This provided an opportunity to explore potential changes in the structure and pattern of the subtidal estuarine macrozoobenthic community. Salinity changes were minimal after mouth opening, decreasing by c. 4 and 8 in the lower and upper estuary, respectively. Salinity decrease was due to river dominance over tidal influence. Two biotic assemblages, structured by sediment characteristics, typified the community throughout the study: a sand-associated group near the mouth and a mud-associated group upstream. Amphipods were proportionally the most abundant group within each assemblage and on each sampling occasion. At the species level, high variability typified the community, with no trends or patterns observed. However, species richness declined from 27–30 to 23 after mouth opening. The number of species returned to former levels at the time of the final survey and just before final mouth closure. An analysis of the subtidal macrozoobenthos in the East Kleinemonde and other temporarily open/closed estuaries (TOCEs) of similar size in the bioregion indicated that communities were typically composed of relatively few, broadly tolerant euryhaline species with no species unique to TOCEs.     

Yellow perch genetic structure and habitat use among connected habitats in eastern Lake Michigan

Maintenance of genetic and phenotypic diversity is widely recognized as an important conservation priority, yet managers often lack basic information about spatial patterns of population structure and its relationship with habitat heterogeneity and species movement within it. To address this knowledge gap, we focused on the economically and ecologically prominent yellow perch (Perca flavescens). In the Lake Michigan basin, yellow perch reside in nearshore Lake Michigan, including drowned river mouths (DRMs)—protected, lake‐like habitats that link tributaries to Lake Michigan. The goal of this study was to examine the extent that population structure is associated with Great Lakes connected habitats (i.e., DRMs) in a mobile fish species using yellow perch as a model. Specifically, we tested whether DRMs and eastern Lake Michigan constitute distinct genetic stocks of yellow perch, and if so, whether those stocks migrate between the two connected habitats throughout the year. To do so, we genotyped yellow perch at 14 microsatellite loci collected from 10 DRMs in both deep and littoral habitats during spring, summer, and autumn and two nearshore sites in Lake Michigan (spring and autumn) during 2015–2016 and supplemented our sampling with fish collected in 2013. We found that yellow perch from littoral‐DRM habitats were genetically distinct from fish captured in nearshore Lake Michigan. Our data also suggested that Lake Michigan yellow perch likely use deep‐DRM habitats during autumn. Further, we found genetic structuring among DRMs. These patterns support hypotheses of fishery managers that yellow perch seasonally migrate to and from Lake Michigan, yet, interestingly, these fish do not appear to interbreed with littoral fish despite occupying the same DRM. We recommend that fisheries managers account for this complex population structure and movement when setting fishing regulations and assessing the effects of harvest in Lake Michigan.     

Do the habitats,mouth morphology and diets of the mullids Upeneichthys stotti and U. lineatus in coastal waters of south-western Australia differ?

Two benthic carnivorous goatfish (Mullidae), Upeneichthys stotti (max total length, L _T= 179 mm) and U. lineatus (max L _T= 257 mm), were trawled from the inner continental shelf waters of Western Australia. U. stotti was found almost exclusively offshore at 20–35 m depth, while U. lineatus was most abundant inshore at 5–15 m depth. Smaller individuals of both species ate small, thin-shelled mysids, tanaids and amphipods, while larger fish ate large, hard-bodied isopods, carid decapods and brachyuran crabs. Classification and ordination of the mean volumetric percentage contributions of the prey (dietary samples) of both species from all sites and in each season did not lead to a clear separation between these two species. However, ordination demonstrated that the dietary samples of the two species were distinct when the two species were found together, and when fish of sequential 20-mm length intervals were used. The interspecific size-class differences were consistent with the results obtained using Schoener's overlap index, for which values >0·6 were recorded for only two of the 45 possible interspecific pairwise comparisons. Since these interspecific differences occurred despite virtually identical mouth sizes and morphologies, the two species must feed in a slightly different manner and/or in different microhabitats. While most comparable-sized fish ate tanaids and amphipods, U. stotti ate more relatively mobile epibenthic mysids, cumaceans and carid decapods, whereas U. lineatus ate more larger and slower-moving burrowing bivalves, onuphid polychaetes and brachyuran crabs. The partial partitioning of habitats, when combined with differences in the diet, would help facilitate the co-existence of these two mullids when they are abundant.     

Intraspecific brood mixing and reduced polyandry in a maternal mouth-brooding cichlid

Microsatellite loci were used to evaluate the level of polyandryand intraspecific brood mixing in Protomelas c.f. spilopterus,a paedophagous, maternal mouth-brooding cichlid from Lake MakaiAfrica. We found that broods were fertilized by one to threemales, which was a reduced level of multiple paternity comparedto other mouth-brooding cichlids. Low density of breeding malesand the risk of intraspecific predation are likely explanationsfor reduced polyandry. Intraspecific brood-mixing was foundin four out of the six broods examined, with the proportionsof foreign fry ranging from 6% to 65%. The potential originsof brood mixing are discussed, although no firm conclusionscan be drawn given the limited behavioral observations for thisspecies.