A co-invasive microsporidian parasite that reduces the predatory behaviour of its host Dikerogammarus villosus (Crustacea, Amphipoda)

SUMMARYParasites are known to affect the predatory behaviour or diet of their hosts. In relation to biological invasions, parasites may significantly influence the invasiveness of the host population and/or mediate the relationships between the invader and the invaded community. Dikerogammarus villosus, a recently introduced species, has had a major impact in European rivers. Notably, its high position in trophic web and high predatory behaviour, have both facilitated its invasive success, and affected other macroinvertebrate taxa in colonized habitats. The intracellular parasite Cucumispora dikerogammari, specific to D. villosus, has successfully dispersed together with this amphipod. Data presented here have shown that D. villosus infected by this parasite have a reduced predatory behaviour compared with healthy individuals, and are much more active suggesting that the co-invasive parasite may diminish the predatory pressure of D. villosus on newly colonized communities.

Download Full-text

What doesn’t kill you doesn’t make you stronger: Parasites modify interference competition between two invasive amphipods

NeoBiota ◽

10.3897/neobiota.69.73734 ◽

2021 ◽

Vol 69 ◽

pp. 51-74

Author(s):

Jarosław Kobak ◽

Michał Rachalewski ◽

Karolina Bącela-Spychalska

Keyword(s):

Biological Invasions ◽

Interspecific Interactions ◽

Interference Competition ◽

Dikerogammarus Villosus ◽

Heterospecific Male ◽

Invasive Amphipods ◽

Cucumispora Dikerogammari ◽

Dikerogammarus Haemobaphes

We used a freshwater amphipod-microsporidian model (Ponto-Caspian hosts: Dikerogammarus villosus and D. haemobaphes, parasite: Cucumispora dikerogammari) to check whether parasites affect biological invasions by modulating behaviour and intra- and interspecific interactions between the invaders. We tested competition for shelter in conspecific and heterospecific male pairs (one or both individuals infected or non-infected). In general, amphipods of both species increased their shelter occupancy time when accompanied by infected rather than non-infected conspecifics and heterospecifics. Infected amphipods faced lower aggression from non-infected conspecifics. Moreover, D. villosus was more aggressive than D. haemobaphes and more aggressive towards conspecifics vs. heterospecifics. In summary, infection reduced the intra- and interspecific competitivity of amphipods, which became less capable of defending their shelters, despite their unchanged need for shelter occupancy. Dikerogammarus haemobaphes, commonly considered as a weaker competitor, displaced by D. villosus from co-occupied locations, was able to compete efficiently for the shelter with D. villosus when microsporidian infections appeared on the scene. This suggests that parasites may be important mediators of biological invasions, facilitating the existence of large intra- and interspecific assemblages of invasive alien amphipods.

Download Full-text

Effects of geographic isolation on anti-snakes responses in the wall lizard, Podarcis muralis

Amphibia-Reptilia ◽

10.1163/156853812x636448 ◽

2012 ◽

Vol 33 (2) ◽

pp. 199-206 ◽

Cited By ~ 8

Author(s):

Jonas Durand ◽

Arnaud Legrand ◽

Mélodie Tort ◽

Alice Thiney ◽

Radika J. Michniewicz ◽

...

Keyword(s):

Choice Experiment ◽

Behavioural Plasticity ◽

The Novel ◽

Geographic Isolation ◽

Podarcis Muralis ◽

Predatory Behaviour ◽

Snake Species ◽

Predator Response ◽

The Cost ◽

Predatory Pressure

Alteration in anti-predatory behaviour following geographic isolation has been observed in a number of taxa. Such alteration was attributed to the effect of relaxed selection in the novel environment, reinforced by the cost of anti-predatory behaviours. We studied aspects of anti-snake behaviour in 987 adult and juvenile wall lizards Podarcis muralis from two mainland areas (heavy snake predatory pressure) and two islands (low snake predatory pressure), isolated from the mainland 5000 and 7000 years ago. We conducted a scented retreat site choice experiment using the odours of five different snake species (saurophagous, piscivorous or generalist feeder). Mainland lizards avoided shelters scented by saurophagous snakes, but not those scented by non saurophagous snake species. Long isolated lizards (7000 years ago) showed no anti-predator response to any snake, suggesting a total loss of anti-predatory behaviour towards saurophagous snakes. More recently isolated lizards (5000 years ago) however showed anti-snake behaviour towards a former sympatric adder species, and a tendency to avoid the scent of a sympatric generalist feeder snake. There was no difference in the anti-snake responses between adult and juvenile wall lizards from all four sites, suggesting a limited role for experience (behavioural plasticity) in the expression of anti-snake behaviour in wall lizards.

Download Full-text

Predatory impact of the freshwater invader Dikerogammarus villosus (Crustacea: Amphipoda)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f02-074 ◽

2002 ◽

Vol 59 (6) ◽

pp. 1078-1084 ◽

Cited By ~ 140

Author(s):

Jaimie T.A Dick ◽

Dirk Platvoet ◽

David W Kelly

Keyword(s):

Great Lakes ◽

North American ◽

Field Studies ◽

Freshwater Ecosystems ◽

Predatory Behaviour ◽

Dikerogammarus Villosus ◽

The North ◽

North American Great Lakes ◽

Body Sizes ◽

Predatory Impact

To assess the increasing threats to aquatic ecosystems from invasive species, we need to elucidate the mechanisms of impacts of current and predicted future invaders. Dikerogammarus villosus, a PontoCaspian amphipod crustacean, is invading throughout Europe and predicted to invade the North American Great Lakes. European field studies show that populations of macroinvertebrates decline after D. villosus invasion. The mechanism of such impacts has not been addressed empirically; however, D. villosus is known to prey upon and replace other amphipods. Therefore, in this study, we used microcosm and mesocosm laboratory experiments, with both single and mixed prey species scenarios, to assess any predatory impact of D. villosus on a range of macroinvertebrate taxa, trophic groups, and body sizes. Dikerogammarus villosus predatory behaviour included shredding of prey and infliction of "bite" injuries on multiple victims. Dikerogammarus villosus killed significantly greater numbers of macroinvertebrates than did the native Gammarus duebeni, which is currently being replaced by D. villosus. This invader thus appears to impact on freshwater ecosystems through its exceptional predatory capabilities. We predict that future invasions by D. villosus will have serious direct and indirect effects on freshwaters, with its invasion facilitated in a larger "invasional meltdown" in regions like the North American Great Lakes.

Download Full-text

Ecological impacts of the microsporidian parasite Pleistophora mulleri on its freshwater amphipod host Gammarus duebeni celticus

Parasitology ◽

10.1017/s0031182005007754 ◽

2005 ◽

Vol 131 (3) ◽

pp. 331-336 ◽

Cited By ~ 23

Author(s):

N. J. FIELDING ◽

C. MacNEIL ◽

N. ROBINSON ◽

J. T. A. DICK ◽

R. W. ELWOOD ◽

...

Keyword(s):

Interspecific Interactions ◽

Parasite Burden ◽

Parasite Prevalence ◽

Abdominal Muscle ◽

Host Population ◽

Ecological Impacts ◽

Activity Level ◽

Microsporidian Parasite ◽

Individual Host ◽

Invasive Amphipod

The microsporidian parasite, Pleistophora mulleri, infects the abdominal muscle of the freshwater amphipod Gammarus duebeni celticus. We recently showed that P. mulleri infection was associated with G. d. celticus hosts being more vulnerable to predation by the invasive amphipod Gammarus pulex. Parasitized G. d. celticus also had a reduced ability to prey upon other co-occurring amphipods. We suggested the parasite may have pervasive influences on host ecology and behaviour. Here, we examine the association between P. mulleri parasitism and parameters influencing individual host fitness, behaviour and interspecific interactions. We also investigate the relationship between parasite prevalence and host population structure in the field. In our G. d. celticus study population, P. mulleri prevalence was strongly seasonal, ranging from 8·5% in summer to 44·9% in winter. The relative abundance of hosts with the heaviest parasite burden increased during summer, which coincided with high host mortality, suggesting that parasitism may regulate host abundance to some degree. Females were more likely to be parasitized than males and parasitized males were paired with smaller females than unparasitized males. Parasitism was associated with reduction in the host's activity level and reduced both its predation on the isopod Asellus aquaticus and aggression towards precopula pairs of the invasive G. pulex. We discuss the pervasive influence of this parasite on the ecology of its host.

Download Full-text

Predator recognition and anti-predatory behaviour in a recent aquatic invader, the killer shrimp (Dikerogammarus villosus)

10.1101/636100 ◽

2019 ◽

Author(s):

Matteo Rolla ◽

Sonia Consuegra ◽

Carlos Garcia de Leaniz

Keyword(s):

Predator Recognition ◽

Test Arena ◽

Predatory Behaviour ◽

Dikerogammarus Villosus ◽

Fish Kairomones ◽

Aggregation Behaviour ◽

Significant Difference ◽

Fish Predators ◽

Open Test ◽

Predator Threat

AbstractThe killer shrimp (Dikerogammarus villosus) is one of the most recent, but also most damaging, aquatic invasive species in Europe, but information on how the species responds to novel predation pressures in recently invaded areas is very limited. We employed an open test arena to examine predator recognition and anti-predatory behaviour in killer shrimp exposed to either blank water or water conditioned with fish kairomones to simulate a predator threat. Within five years after their introduction, killer shrimp spent much more time hiding in the presence of fish kairomones than when they were exposed to blank water. However, no significant difference was found in aggregation behaviour, and killer shrimp were strongly attracted to the scent of conspecifics regardless of predator threat. Given the strong selective pressures that fish predators can exert on native and invasive gammarids, our findings highlight the need to consider prey-predator interactions to better predict the dispersal and likely impact of killer shrimp into invaded ecosystems.

Download Full-text

Predator recognition and anti-predatory behaviour in a recent aquatic invader, the killer shrimp (Dikerogammarus villosus)

Aquatic Invasions ◽

10.3391/ai.2020.15.3.08 ◽

2020 ◽

Vol 15 (3) ◽

pp. 482-496

Author(s):

Matteo Rolla ◽

Sofia Consuegra ◽

Carlos de Leaniz

Keyword(s):

Predator Recognition ◽

Predatory Behaviour ◽

Dikerogammarus Villosus

Download Full-text

Explaining the microbial diversity conundrum: can microbiome composition be crucial for host fitness, while highly divergent among healthy individuals?

10.1101/2022.01.03.474762 ◽

2022 ◽

Author(s):

Itay Daybog ◽

Oren Kolodny

Keyword(s):

Empirical Studies ◽

Host Population ◽

Healthy Individuals ◽

Apparent Paradox ◽

Computational Framework ◽

Rescue Effect ◽

Host Fitness ◽

Microbiome Composition ◽

Β Diversity ◽

Selection Dynamics

Recent empirical studies offer conflicting findings regarding the relation between host fitness and the composition of its microbiome, a conflict which we term the microbial β-diversity conundrum: it has been shown that the microbiome is crucial for host wellbeing and survival. At the same time, different healthy individuals' microbiome compositions, even in the same population, often differ dramatically, contrary to the notion that a vital trait should be highly conserved. Moreover, gnotobiotic individuals exhibit highly deleterious phenotypes, supporting the notion that the microbiome is paramount to host fitness. However, the introduction of almost arbitrarily selected microbiota into the system often achieves a significant rescue effect of the deleterious phenotypes, even microbiota from soil or phylogenetically distant host species, highlighting an apparent paradox. Here we suggest several solutions to the paradox using a computational framework, simulating the population dynamics of hosts and their microbiomes over multiple generations. The answers, relating to factors such as host population size, the specific mode of contribution of the microbes to host fitness, and the typical microbiome richness, offer solutions to the conundrum by creating scenarios where even when a host's fitness is determined in full by its microbiome composition, this composition has little or no effect on the natural selection dynamics of the population.

Download Full-text

Morphological and elemental analysis of isolated incubated frog retina-choroid

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111604 ◽

1984 ◽

Vol 42 ◽

pp. 298-299

Author(s):

B. J. Panessa-Warren ◽

J. B. Warren ◽

H. W. Kraner

Keyword(s):

Elemental Analysis ◽

Pigment Epithelium ◽

Human Retina ◽

Healthy Individuals ◽

Anterior Portion ◽

Pathological Conditions ◽

Frog Retina ◽

Isolated Retina ◽

Vertebrate Eye ◽

Retina Pigment Epithelium

Our previous studies have demonstrated that abnormally high amounts of calcium (Ca) and zinc (Zn) can be accumulated in human retina-choroid under pathological conditions and that barium (Ba), which was not detected in the eyes of healthy individuals, is deposited in the retina pigment epithelium (RPE), and to a lesser extent in the sensory retina and iris. In an attempt to understand how these cations can be accumulated in the vertebrate eye, a morphological and microanalytical study of the uptake and loss of specific cations (K, Ca,Ba,Zn) was undertaken with incubated Rana catesbiana isolated retina and RPE preparations. Large frogs (650-800 gms) were dark adapted, guillotined and their eyes enucleated in deep ruby light. The eyes were hemisected behind the ora serrata and the anterior portion of the eye removed. The eyecup was bisected along the plane of the optic disc and the two segments of retina peeled away from the RPE and incubated.

Download Full-text