120 research outputs found
Mutual mate choice in crayfish: large body size is selected by both sexes, virginity by males only.
Assessing mate size in the red swamp crayfish Procambarus clarkii: effects of chemical versus visual stimuli.
Evidence of female cryptic choice in crayfish.
To test whether male body size affects female reproductive investment in the polygamous crayfish Procambarus clarkii, we described mating behaviour of virgin females paired with either small or large males, and analysed the number, size and weight of both eggs and juveniles sired by either types of male. Along with confirming the overt selection by females of larger mates, we found that the size and weight of both the eggs and the juveniles were higher when sired by larger fathers. This suggests that P. clarkii females exert a form of cryptic choice for large males, seemingly adjusting the quantity of egg deutoplasm in function of the mate body size. The question of why females spend time and energy to brood low-fitness offspring is finally raised
Habitat use and dispersal of the invasive crayfish Procambarus clarkii in ephemeral water bodies of Portugal.
We used radio-telemetry to analyze habitat use and dispersal of the invasive crayfish Procambarus clarkii in the extreme environmental conditions of a temporary river in southern Portugal. The
rationale of this study was that an understanding of the properties that make this species a successful invader can be of help for the conservation of freshwater biodiversity. The results showed that:
(1) crayfish displaced at a similar rate (ranging 2.5–38md 1) as other European populations; (2)movement was faster at night; (3) crayfish movement had no clear environmental correlates, except
for water temperature; (4) peaks of more intense locomotion were intercalated with longer periods of slow or null speed; and (5) P. clarkii did not excavate burrows in the study habitat, but took refuge under boulders and most often occupied complex microhabitats (e.g., vegetated sections of the river). The conclusion was that, notwithstanding their extreme conditions, ephemeral water bodies in southern Europe are highly susceptible to invasion by P. clarkii
Behavioral plasticity, behavioral syndromes and animal personality in crustacean decapods: An imperfect map is better than no map
Abstract
Despite their key role as model organisms in many behavioral studies, crustacean decapods have been only slightly touched upon by the recent surge of scientific interest in animal personality. Only seven articles investigated the issue in a handful of species among hermit crabs, crabs, and crayfish. Obviously, a limited number of publications does not mean that personality is rare in decapods. On the contrary, few studies might be the result of a form of reluctance by behavioral ecologists to deal with such a phenomenon in these and other invertebrates. This reluctance contrasts with the enthusiasm shown in tackling the behavioral plasticity issue. Here we discuss the possible theoretical and methodological difficulties raised by applying the animal personality perspective to decapods and analyze implications of personality studies for their ecology, conservation, and welfare. By highlighting gaps in knowledge and directions of future research, our intention is to increase scientific emphasis on the issue
Interrelationships among Egg, Larvae and Maternal Characteristics in Persian Sturgeon Acipenser persicus
This study was aimed to observe the correlations among egg, larvae and maternal characteristics of Persian sturgeon. A total of 41 females were used and the variables including fertilization rate, incubation survival rate, larvae survival rate during yolk sac absorption (before feeding), and larvae survival rate after first feeding were determined. As a result, fertilization rate was positively correlated with three variables: incubation survival, larvae survival during yolk sac absorption, and GSI (gonadosomatic index). Also, maternal size (age, weight, total length) did not show a significant relation (P > 0.05) with incubation survival, larvae survival during yolk sac absorption and larvae survival at first feeding stage
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