Search results for "Fish"

Optogenetic Interpellation of Behavior Employing Unrestrained Zebrafish Larvae

2017

Die Alkalireserven des männlichen und weiblichen Blutes des Fisches Crenilabrus pavo C.V. [Vīrišķu un sievišķu asiņu alkalirezerves zivju sugā Crenil…

1933

Teksts vācu valodā, kopsavilkums latviešu valodā.

The sexual specificness of the skin pigments of the fishes of the genus Crenilabrus colorimetrically investigated [Kolorimetrisks pētījums par Crenil…

1929

Izvilkums no: Latvijas Bioloģijas biedrības raksti, sēj.1., oktobris,1929. Teksts angļu valodā, kopsavilkums latviešu valodā.

Parasite resistance and avoidance behaviour in preventing eye fluke infections in fish.

2004

This paper examines the efficiency of acquired resistance in protecting the fish host, rainbow trout (Oncorhynchus mykiss), against the trematode parasite Diplostomum spathaceum, and the hypothesis that fish recognize areas where infective stages are aggregated and show avoidance behaviour. We found that when fish with a low level of infection were held in restricted cages in natural conditions they became infected and developed cataracts as a result of this infection. This suggests that acquired resistance is insufficient in protecting fish against the parasite or the deleterious effects of infection in conditions where fish could not avoid the parasite. Behavioural experiments in the labo…

Baltijas reņģes nārsta vietu un embrionālās attīstības raksturojums Rīgas jūras līcī

1994

Advisor: L. Duškina

Morphometrics of hard structures in cuttlefish

2006

7 pages; International audience; Cuttlefishes exhibit several hard structures that have been characterised using morphometric analysis. Most of these data come from cuttlebones, although statoliths and beaks are also used. It appears that morphometric techniques are mainly used for taxonomic purposes. However, some analyses have emphasised functional morphology and macroevolution. Morphological features (including the inner shell) of cuttlefishes and their availability for study (numerous specimens, culture in the laboratory) make them a first rank model for numerous studies in life sciences that require morphometrics, and especially in the field of evolutionary biology.

Increased susceptibility to predation and altered anti-predator behaviour in an acanthocephalan-infected amphipod.

2007

7 pages; International audience; According to the 'parasitic manipulation hypothesis', phenotypic changes induced by parasites in their intermediate hosts are effective means of increasing trophic transmission to final hosts. One obvious prediction, although seldom tested, is that increased vulnerability of infected prey to an appropriate predator should be achieved by the parasite altering the anti-predator behaviour of its intermediate host. In this study, we tested this prediction using the fish acanthocephalan Pomphorhynchus tereticollis and the freshwater amphipod Gammarus pulex. Firstly, we estimated the relative vulnerability of infected and uninfected gammarids to predation by the b…

Infection with acanthocephalans increases the vulnerability of Gammarus pulex (Crustacea, Amphipoda) to non-host invertebrate predators.

2008

SUMMARYPhenotypic alterations induced by parasites in their intermediate hosts often result in enhanced trophic transmission to appropriate final hosts. However, such alterations may also increase the vulnerability of intermediate hosts to predation by non-host species. We studied the influence of both infection with 3 different acanthocephalan parasites (Pomphorhynchus laevis, P. tereticollis, and Polymorphus minutus) and the availability of refuges on the susceptibility of the amphipod Gammarus pulex to predation by 2 non-host predators in microcosms. Only infection with P. laevis increased the vulnerability of amphipods to predation by crayfish, Orconectes limosus. In contrast, in the ab…

Manipulative parasites may not alter intermediate host distribution but still enhance their transmission: field evidence for increased vulnerability …

2013

SUMMARYBehavioural alterations induced by parasites in their intermediate hosts can spatially structure host populations, possibly resulting in enhanced trophic transmission to definitive hosts. However, such alterations may also increase intermediate host vulnerability to non-host predators. Parasite-induced behavioural alterations may thus vary between parasite species and depend on each parasite definitive host species. We studied the influence of infection with 2 acanthocephalan parasites (Echinorhynchus truttae and Polymorphus minutus) on the distribution of the amphipod Gammarus pulex in the field. Predator presence or absence and predator species, whether suitable definitive host or …

Carotenoid-based colour of acanthocephalan cystacanths plays no role in host manipulation.

2009

Manipulation by parasites is a catchy concept that has been applied to a large range of phenotypic alterations brought about by parasites in their hosts. It has, for instance, been suggested that the carotenoid-based colour of acanthocephalan cystacanths is adaptive through increasing the conspicuousness of infected intermediate hosts and, hence, their vulnerability to appropriate final hosts such as fish predators. We revisited the evidence in favour of adaptive coloration of acanthocephalan parasites in relation to increased trophic transmission using the crustacean amphipodGammarus pulexand two species of acanthocephalans,Pomphorhynchus laevisandPolymorphus minutus. Both species show car…