Spatial-temporal distribution and recruitment of Stramonita haemastoma (Linnaeus, 1758) (Mollusca) on a sandstone bank in Ilhéus, Bahia, Brazil

We examined aspects of the population ecology of the gastropod Stramonita haemastoma at Ilhéus, Bahia, Brazil. We collected monthly from October 2007 through September 2008 on a sandstone bank 1.5 km long, on which two points and two sampling levels were defined. We took five previously randomised replicates at each level, using a square enclosing an area of 0.0625 m². The snails were photographed, counted, and measured at the site. Both recruits and other individuals in the population preferentially inhabit the regions closer to the lower shore, where they are submerged for longer periods and are less subject to physiological stresses caused by temperature variation and desiccation. The cracks and holes in the bank serve as refuges and places for S. haemastoma to lay their egg capsules. Recruits were observed throughout the study period, and the population showed continuous reproduction.

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Reproductive features of the swimming crab Callinectes danae(Crustacea, Portunoidea) on the subtropical coast of Brazil: a sampling outside the estuary

Brazilian Journal of Biology ◽

10.1590/1519-6984.21513 ◽

2015 ◽

Vol 75 (3) ◽

pp. 692-702 ◽

Cited By ~ 7

Author(s):

LS Andrade ◽

M Antunes ◽

PA Lima ◽

M Furlan ◽

IF Frameschi ◽

...

Keyword(s):

Sexual Maturity ◽

Temporal Distribution ◽

Reproductive Pattern ◽

Swimming Crab ◽

Exposed Area ◽

Continuous Reproduction ◽

Spatio Temporal ◽

Marine Areas ◽

Reproductive Females ◽

Callinectes Danae

AbstractThe life cycle of the crab Callinectes danae is estuarine-dependent, and studies on aspects of their biology should also cover marine areas. The present study investigated the sexual maturity, as well as habitat preference by adults in different gonadal stages, and the crabs’ reproductive periodicity outside the estuary. Three bays on the subtropical southeastern coast of Brazil were sampled monthly for two years. For each bay, six transects were established, four of them parallel to the beach line (5, 10, 15 and 20 m depth), as well as one transect in an exposed area, and another sheltered from the action of waves. The results showed that the pattern of spatio-temporal distribution of adults C. danae was similar in three bays, although the highest abundance was found in Ubatumirim. Females with developed gonads/ovigerous females were found in greater abundance than females with rudimentary/developing gonads, mainly in deeper transects. Although the areas sampled have different environmental characteristics, the reproductive pattern of the species did not change, showing continuous reproduction throughout, with more abundance of reproductive females on spring and summer. Males reached maturity at larger sizes than females in all three bays.

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Extinction and the temporal distribution of macroevolutionary bursts

10.1101/725689 ◽

2019 ◽

Author(s):

Stephen P. De Lisle ◽

David Punzalan ◽

Njal Rollinson ◽

Locke Rowe

Keyword(s):

Population Dynamics ◽

Parameter Space ◽

Population Ecology ◽

Temporal Distribution ◽

Real Data ◽

Phenotypic Evolution ◽

Deep Time ◽

Important Contributor ◽

Alternative Perspective

ABSTRACTPhenotypic evolution through deep time is slower than expected from microevolutionary rates. This is the paradox of stasis. Previous models suggest stasis occurs because populations track adaptive peaks that typically move on million-year intervals, raising the equally perplexing question of why peaks shifts are so rare. Here, we consider the possibility that peaks can move more rapidly than populations can adapt, resulting in extinction. We model peak movement with explicit population dynamics, parameterized with published microevolutionary parameters. Allowing extinction greatly increases the parameter space of peak movements that yield the appearance of stasis observed in real data through deep time. Our work highlights population ecology as an important contributor to macroevolutionary dynamics, presenting an alternative perspective on the paradox of stasis where apparent constraint on phenotypic evolution in deep time reflects our restricted view of the subset of earth’s lineages that were fortunate enough to reside on relatively stable peaks.

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