Intraspecific cleaning behaviour in Cyprinus carpio in aquaria

Intraspecific cleaning behaviour of diseased juvenile Cyprinus carpio L, in experimental tanks in Wuxi, China has been observed and is described.     

Cleaner shrimp use a rocking dance to advertise cleaning service to clients

Signals transmit information to receivers about sender attributes, increase the fitness of both parties, and are selected for in cooperative interactions between species to reduce conflict [1, 2]. Marine cleaning interactions are known for stereotyped behaviors [3-6] that likely serve as signals. For example, "dancing" and "tactile dancing" in cleaner fish may serve to advertise cleaning services to client fish [7] and manipulate client behavior [8], respectively. Cleaner shrimp clean fish [9], yet are cryptic in comparison to cleaner fish. Signals, therefore, are likely essential for cleaner shrimp to attract clients. Here, we show that the yellow-beaked cleaner shrimp [10] Urocaridella sp. c [11] uses a stereotypical side-to-side movement, or "rocking dance," while approaching potential client fish in the water column. This dance was followed by a cleaning interaction with the client 100% of the time. Hungry cleaner shrimp, which are more willing to clean than satiated ones [12], spent more time rocking and in closer proximity to clients Cephalopholis cyanostigma than satiated ones, and when given a choice, clients preferred hungry, rocking shrimp. The rocking dance therefore influenced client behavior and, thus, appears to function as a signal to advertise the presence of cleaner shrimp to potential clients.     

Microhabitats of sharknose goby (Elacatinus evelynae) cleaning stations and their links with cleaning behaviour

Coral Reefs - Coral reefs are renowned for the complexity of their habitat structures and their resulting ability to host more species per unit area than any another marine ecosystem. Dedicated...     

Variation in posing behaviour among fish species visiting cleaning stations

The adaptive significance of posing behaviour by fish visiting cleaning stations on a Barbadian fringing reef was investigated. The probability of a visitor being cleaned by cleaning gobies ( Elacatinus spp.) was significantly higher after posing than after failing to pose upon arrival at a cleaning station. Despite this, not all visitors posed, and there was much variation among species in tendency to pose. This interspecific variation was not related to the probability of being cleaned, either after posing or after failing to pose, nor was it related to trophic level or fish total length. The latter was true both for cross-species analyses and phylogenetically independent contrasts. A cost-benefit model is proposed to understand interspecific variation in posing behaviour, which considers both decisions by clients and by cleaners. As well as explaining the results, this may reconcile differences among anecdotal and experimental observations from previous studies.     

虾池清塘排出物沉积厚度对老鼠簕幼苗的影响

模拟直接排入红树林的虾池清塘排出物在林地的不同沉积厚度（0、2、4、8 cm）,研究其对培养424 d的红树植物老鼠簕（Acanthus ilicifolius）幼苗生长和生理的影响。清塘排出物的加入对老鼠簕幼苗茎高、基径、叶片数、叶面积、生物量和相对生长率等生长指标都有显著促进作用。总体长势表现为沉积厚度8 cm>4 cm> 2 cm>0 cm。生长指标显示只需少量清塘排出物的沉积（沉积厚度2 cm、4 cm）就能对幼苗的生长产生明显的促进作用,但大量排出物沉积的积累并不会带来更明显的促进作用。清塘排出物沉积的加入能显著提高叶片光合能力,尤其利于叶绿素a的合成。沉积厚度2 cm和4 cm时,幼苗叶片游离脯氨酸的积累并不显著,但丙二醛、可溶性糖、可溶性蛋白含量显著高于正常水平;沉积厚度8 cm则使叶片中游离脯氨酸、丙二醛和水溶性化合物均有大量积累;而叶片中抗氧化酶活性只有在大量沉积物加入（沉积厚度8 cm）时才显著低于对照组水平。总之,老鼠簕幼苗对清塘排出物沉积厚度4 cm以下具有较强的抗逆性和适应力,沉积厚度8 cm会使老鼠簕幼苗受到一定程度的逆境伤害,但本实验期间还未影响其生长。     

Correction to: Microhabitats of sharknose goby (Elacatinus evelynae) cleaning stations and their links with cleaning behaviour

Coral Reefs - A correction to this paper has been published: https://doi.org/10.1007/s00338-021-02111-z     

Punishment and partner switching cause cooperative behaviour in a cleaning mutualism

What are the mechanisms that prevent partners from cheating in potentially cooperative interactions between unrelated individuals? The cleaner fish Labroides dimidiatus and client reef fish both benefit from an interaction as long as the cleaner eats ectoparasites. However, the cleaner fish prefers some client mucus, which constitutes cheating. Field observations suggested that clients control such cheating by using punishment (chasing the cleaner) or by switching partners (fleeing from the cleaner). Here, we tested experimentally whether such client behaviours result in cooperative cleaner fish. Cleaners were allowed to feed from Plexiglas plates containing prawn items and fish flake items. A lever attached to the plates allowed us to mimic the behaviours of clients. As cleaners showed a strong preference for prawn over flakes, we taught them that eating their preferred food would cause the plate to either chase them or to flee, while feeding on flakes had no negative consequences. We found a significant shift in cleaner fish foraging behaviour towards flake feeding after six learning trials. As punishment and terminating an interaction resulted in the cleaners feeding against their preferences in our experiment, we propose that the same behaviours in clients improve the service quality of cleaners under natural conditions.     

Fish odour triggers conspecific attraction behaviour in an aquatic invertebrate

Group living has evolved as an adaptation to predation in many animal species. In a multitude of vertebrates, the tendency to aggregate varies with the risk of predation, but experimental evidence for this is less well known in invertebrates. Here, we examine the tendency to aggregate in the freshwater amphipod Gammarus pulex in the absence and presence of predator fish odour. Without fish odour, the gammarids showed no significant tendency to aggregate. In contrast to this, in fish-conditioned water, they significantly preferred to stay close to conspecifics. Predation risk can, thus, influence gammarids social behaviour.     

Fish by‐catch in shrimp beam trawls in the northern South China Sea

The by‐catch of shrimp beam trawl fisheries in the northern South China Sea were estimated during the 2005–2006 and 2012–2013 fishing seasons. A total of 98 hauls from three important shrimp fishing grounds were used in the analyses. A total of 119 by‐catch species were captured, compared with only 15 target species. The ratio of by‐catch to shrimp ranged from 1.01 to 13.90. The dominant standard length (SL) range of fish by‐catch was 51–100 mm. The percentage of juveniles in the total catch of some fish species was high (e.g. 100% for A. aneus).     

Antifouling adaptations of marine shrimp (Decapoda: Caridea): gill cleaning mechanisms and grooming of brooded embryos

Gills in the branchial chambers of caridean shrimps, as well as the brooded embryos in females, are subject to fouling by particulate debris and epizoites. Important mechanisms for cleaning the gills are brushing of the gills by the grooming or cleaning chelipeds in some species, while in others, setae from the bases of the thoracic legs brush up among the gills during movement of the limbs (epipodsetobranch complexes). Setae of cleaning chelipeds and of epipod-setobranch complexes show similar ultrastructural adaptions for scraping gill surfaces. Ablation of the cleaning chelipeds of the shrimp Heptacarpus pictus results in severe fouling of the gills in experimentals, while those of controls remain clean. Embryos brooded by female carideans are often brushed and jostled by the grooming chelipeds. In H. pictus , removal of the cleaning chelae results in heavier microbial and sediment fouling than in controls.     

The importance of nest cleaning in egg rejection behaviour of great reed warblers Acrocephalus arandinaceas

We tested the importance of nest cleaning in egg rejection behaviour of the great reed warbler Acrocephalus arundinaceus in a highly parasitised population in which about 64% of nests are parasitised by the common cuckoo Cuculus canorus . Three types of objects of the same weight, texture and colour but with different shapes (dummy cuckoo eggs, sticks and disks) were placed into great reed warbler nests. We investigated the response of hosts in two stages of breeding: pre-incubation when the risk of brood parasitism is high, and during incubation when the risk of parasitism is low. The dummy cuckoo eggs were rejected less often than the other objects in both breeding stages, although we did not find any difference in the frequency of rejection between pre-incubation and incubation. We integrate these results into current views on the evolution of host–parasite interactions, and propose a hierarchical concept to understand egg rejection behaviour: (1) hosts reject all non-egg shaped objects as a general cleaning mechanism; (2) adaptations for the hosts' ability to recognise their own eggs allows them to distinguish these eggs from similar objects and parasitic eggs.     

Activity of neck-muscle motoneurones during eye cleaning behaviour in the cricket Gryllus campestris

The activity of neck-muscle motoneurones which control head movements during eye cleaning behaviour was recorded from motor nerves with chronically implanted electrodes in unrestrained crickets. We show that motoneurones of the dorso-ventral muscles displayed strong activity differences between both sides of the neck, with higher discharge frequencies either ipsi- or contralateral to the direction of the head movement. Motoneurones innervating dorsal-longitudinal muscles were equally active on both sides. A single excitatory motoneurone of one dorso-ventral muscle showed a discharge pattern unequivocally related to eye cleaning. Lesions of connectives revealed that this motoneurone is monitored by interneuronal pathways from the suboesophageal ganglion although the primary sensory axons eliciting eye cleaning, project into the prothoracic ganglion.     

Snapping behaviour in intraspecific agonistic encounters in the snapping shrimp (Alpheus heterochaelis)

During intraspecific agonistic encounters in snapping shrimp (Alpheus heterochaelis) the behaviour of the snapper, emitting a fast water jet by very rapid closure of the large modified snapper claw, and the receiver was analysed by single frame video analysis before, during, and after the snap. During snapping the opponents usually face each other. Snapping is most frequently preceded by touch of frontal appendages. The snapping animal keeps its snapper claw slightly across the midline, shielding frontal body parts, and its tailfan bent downwards. The mean claw cocking duration (generating muscle tension) before snapping amounts to about 500 ms. In 58% of the snaps, the snapper claw pointed at the opponent, its claws, densely covered with sensory hairs, representing the main target of the water jet. The mean distance for these directed snaps was 0.9 cm, while undirected snaps were emitted from larger distances of on average 3.4 cm. The snapper usually withdraws immediately after snapping, the receiver approaches. Initial snaps are often answered by return snaps and both are emitted from smaller distances and hit more often than subsequent snaps.     

Comparison of the carpal cleaning brush in two genera of hydrothermal vent shrimp (Crustacea,Decapoda, Bresiliidae)

Clusters of specialized serrate setae in patches called “carpal cleaning brushes,” or carpal-propodal brushes, are found on the distal margins of the chelipedal carpus in many species of caridean shrimps and other decapod crustaceans. These brushes, used to clean the antennal flagellum, occur in some bresiliid shrimp species associated with hydrothermal vents in the Pacific and Atlantic oceans, and recently their presence has been proposed as a distinguishing taxonomic character at the genus level. Occurrence of such brushes in shrimp that live near hydrothermal vents is of interest because of the high number of bacteria associated with these vents. These shrimp have the potential to be heavily fouled with bacteria, whereas at the same time preliminary studies suggest that they may depend upon these bacteria at least in part (or possibly exclusively) for food. We employ scanning electron microscopy to examine and describe the general morphology and location of carpal brushes on the chelipeds of all known species in two vent shrimp genera, Rimicaris Williams and Rona and Chorocaris Martin and Hessler. The brush is well developed and clearly delimited in all known species of Chorocaris, where it consists of a triangular field of serrate setae and a posterior blunt spine that possibly functions as a “stop” to keep the antennal flagellum in place during grooming. Rimicaris exoculata has no recognizable carpal cleaning brush or any serrate setae on the chelipedal carpus and thus appears derived relative to species of Chorocaris with regard to this feature. A newly described species, R. aurantiaca, is somewhat intermediate, having no carpal brush but with two serrate setae and a blunt spine in the region occupied by the brush in species of Chorocaris. Possible implications and comparisons to the genera Alvinocaris and Opapaele are discussed briefly. J. Morphol. 235:31–39, 1998. © 1998 Wiley-Liss, Inc.     

Parasite infection rather than tactile stimulation is the proximate cause of cleaning behaviour in reef fish.

Cleaning behaviour is a popular example of non-kin cooperation. However, quantitative support for this is generally sparse and the alternative, that cleaners are parasitic, has also been proposed. Although the behaviour involves some of the most complex and highly developed interspecific communication signals known, the proximate causal factors for why clients seek cleaners are controversial. However, this information is essential to understanding the evolution of cleaning. I tested whether clients seek cleaners in response to parasite infection or whether clients seek cleaners for tactile stimulation regardless of parasite load. Parasite loads on client fish were manipulated and clients exposed to cleaner fish and control fish behind glass. I found that parasitized client fish spent more time than unparasitized fish next to a cleaner fish. In addition, parasitized clients spent more time next to cleaners than next to control fish, whereas unparasitized fish were not attracted to cleaners. This study shows, I believe for the first time, which is somewhat surprising, that parasite infection alone causes clients to seek cleaning by cleaners and provides insight into how this behaviour evolved.