The spatial pattern of Cyprideis torosa (Jones, 1850)(Crustacea: Ostracoda)

Abstract

The spatial pattern of the ostracod Cyprideis torosa (Jones, 1850) is aggregated and can be described by the negative binomial distribution. The fit of the observed distribution to the negative binomial is less well for the total number of females because females that are not carrying eggs tend to be independently distributed from both females carrying eggs and males. The aggregations are roughly circular with a radius of about 13 cm and may be themselves aggregated. A method to picture the aggregations is described.

Distributional patterns of non-marine Ostracoda (Crustacea) in Adiyaman Province (Turkey)

“…Based on this ratio (S 2 /m), several types of the indices of dispersion have been proposed such as Green's index, index of dispersion, index of clumping, standardized Morisita index (Morisita, 1959;Ludwig and Reynolds, 1988). Among them, the index of dispersion is widely used (Heip, 1976) to predict uniform and clumped distribution. Accordingly, if s 2 /m = 1 (Poisson distribution), organisms (or population) show a random distribution, but if s 2 /m > 1 (negative binomial), they display a clumped pattern.…”

“…Published studies are available describing ostracod habitat preferences (Benzie, 1989;Du¨gel et al, 2008), habitat similarities (Sar and Ku¨lko¨ylu¨og˘lu, 2010), and ecology and distribution (Teeter, 1973;Malmqvist et al, 1997;Mezquita et al, 1999;Kiss, 2007;Pieri et al, 2009;Van der Meeren et al, 2010;Ku¨lko¨ylu¨og˘lu et al, 2013). However, with the exception of Heip (1976), there is no specific research on the distributional patterns of ostracods using Poisson probabilities. Heip (1976) attempted to test the spatial pattern of a single species (Cyprideis torosa (Jones, 1850)) in a small brackish pond in Northern Belgium during a single sampling event in January 1971.…”

“…However, with the exception of Heip (1976), there is no specific research on the distributional patterns of ostracods using Poisson probabilities. Heip (1976) attempted to test the spatial pattern of a single species (Cyprideis torosa (Jones, 1850)) in a small brackish pond in Northern Belgium during a single sampling event in January 1971. He concluded that C. torosa showed aggregated distribution in this pond.…”

Cyprideis torosa: a model organism for the Ostracoda?

“…Two methods used to establish production of torosa return values of 9.7 and 9.2 g of dry weight per m 2 per year, with even a total biomass value once found by Heip (1976b) reaching 48.9 g dry weight per m 2 per year; an amazing phenomenon which clearly identifies that torosa is on top of the food chain (Heip 1976a, b). This author also showed that the number of individuals found in his four-year sampling varied between 20 000 and 40 000 individuals per m 2 with, in one instance, numbers reaching 1.8 million specimens per m 2 (at that time adult specimens amounted to c. 15% of the population).…”

Crustaceans from a tropical estuarine sand-mud flat, Pacific, Costa Rica, (1984-1988) revisited

“…In addition, brood protection and the release of juveniles lead to aggregations of individuals. The aggregated distribution of the temperate ostracod Cyprideis torosa has been studied by Heip (1976b), who found that patches have a radius of about 13cm and patterns vary between sexes. The study by Colby & Fonseca (1984) on the spatial pattern (Morisita's index) of the temperate crab Uca pugilator indicates that this species appear to increase aggregation during the colder months.…”