Can a Shore Crab See a Star?

Can a Shore Crab See a Star ?

1. The absolute-intensity threshold of the optokinetic response in the crab Leptograpsus variegatus was measured using a moving continuous monochromatic point source. The results are compared to the photoreceptor responses of the same animal (Doujak, 1984), to determine the photoreceptor signal for the same behavioural threshold stimuli. 2. Optokinetic eye movements demonstrate that at the peak...

Why Can We See a Local Spread of Chikungunya Virus (CHIKV) Infection?

Asymmetry and fighting performance in the shore crab Carcinus maenas.

Fluctuating asymmetries (left-right differences in symmetric traits) can be negatively related to fitness parameters in a number of biological systems. Hence, it has been suggested that symmetric individuals should outcompete asymmetric individuals during intraspecific agonistic encounters. However, there is a lack of experimental evidence for such a relationship. We investigated the relationsh...

The ability to feed in hypoxia follows a seasonally dependent pattern in shore crab Carcinus maenas.

The ability of the adult shore crab Carcinus maenas, native to the Bay of Arcachon (SW France), to feed in hypoxia was determined at various seasons. Crabs previously kept at field temperature were fed after a 5-day fasting period at 15 degrees C. Their blood oxygenation and pH regulation strategy and also their gill anatomy were analysed. From May to October, C. maenas feed at levels of O(2) p...

The anaerobic endproduct lactate has a behavioural and metabolic signalling function in the shore crab

This study presents the first evidence that, in invertebrates, the anaerobic endproduct lactate has an alarm signal function and induces metabolic and behavioural responses as in the anuran Bufo marinus. In support of this function, behavioural hypothermia was demonstrated in the shore crab Carcinus maenas. The animals moved to a cooler environment when exposed to hypoxic conditions. A decrease...