scholarly journals Chaotic genetic patchiness without sweepstakes reproduction in the shore crab Hemigrapsus oregonensis

2016 ◽  
Vol 548 ◽  
pp. 139-152 ◽  
Author(s):  
BH Cornwell ◽  
JL Fisher ◽  
SG Morgan ◽  
JE Neigel
Keyword(s):  
Shore Crab ◽  
Hemigrapsus Oregonensis ◽  
Genetic Patchiness

scholarly journals Long-term change in the parasite burden of shore crabs ( Hemigrapsus oregonensis and Hemigrapsus nudus ) on the northwestern Pacific coast of North America

2021 ◽  
Vol 288 (1945) ◽  
pp. 20203036
Author(s):  
Jessica Quinn ◽  
Sarah Lee ◽  
Duncan Greeley ◽  
Alyssa Gehman ◽  
Armand M. Kuris ◽  
...  
Keyword(s):  
Parasite Burden ◽  
Shore Crab ◽  
Northwestern Pacific ◽  
Intermediate Hosts ◽  
Term Change ◽  
Shore Crabs ◽  
Living Species ◽  
Hemigrapsus Oregonensis ◽  
Over Time

The abundances of free-living species have changed dramatically in recent decades, but little is known about change in the abundance of parasitic species. We investigated whether populations of several parasites have shifted over time in two shore crab hosts, Hemigrapsus oregonensis and Hemigrapsus nudus, by comparing the prevalence and abundance of three parasite taxa in a historical dataset (1969–1970) to contemporary parasite abundance (2018–2020) for hosts collected from 11 intertidal sites located from Oregon, USA, to British Columbia, Canada. Our data suggest that the abundance of the parasitic isopod Portunion conformis has varied around a stable mean for the past 50 years. No change over time was observed for larval acanthocephalans. However, larval microphallid trematodes increased in prevalence over time among H. oregonensis hosts, from a mean of 8.4–61.8% between the historical and contemporary time points. The substantial increase in the prevalence of larval microphallid trematodes could be owing to increased abundances of their bird final hosts, increased production of parasite infective stages by snail intermediate hosts or both. Our study highlights the variability among parasite species in their temporal trajectories of change.

Genetic patchiness of the shore crab Pachygrapsus marmoratus along the Portuguese coast

2009 ◽  
Vol 378 (1-2) ◽  
pp. 50-57 ◽  
Author(s):  
Inês C. Silva ◽  
Natacha Mesquita ◽  
Christoph D. Schubart ◽  
Maria Judite Alves ◽  
José Paula
Keyword(s):  
Shore Crab ◽  
Portuguese Coast ◽  
Pachygrapsus Marmoratus ◽  
Genetic Patchiness

scholarly journals A whiter shade of male: Color background matching as a function of size and sex in the yellow shore crab Hemigrapsus oregonensis (Dana, 1851)

2015 ◽  
Vol 61 (4) ◽  
pp. 729-738 ◽  
Author(s):  
Gregory C. Jensen ◽  
Michael S. Egnotovich
Keyword(s):  
Carapace Width ◽  
Shore Crab ◽  
Differential Mortality ◽  
Striking Difference ◽  
White Background ◽  
Female Size ◽  
White Males ◽  
Color Background ◽  
Hemigrapsus Oregonensis ◽  
Pure White

Abstract Juveniles of the shore crab Hemigrapsus oregonensis are highly variable in color, ranging from the typical yellowishgreen of adults to pure white and myriad patterns of white mottling and other disruptive markings, but large individuals with white coloration appear to be very rare. Using image analysis to quantify the relative “whiteness” of beaches, we sampled crabs from nine locations in Washington State that varied widely in their amount of shell fragments and other light-colored material. The total proportion of white individuals in the different locations was strongly correlated to the proportion of white material on the beaches, but there was a striking difference between sexes. Although white specimens of both sexes declined significantly at sizes above 10 mm carapace width, white females generally persisted throughout the entire female size range on lighter-colored beaches while white males larger than 10 mm were virtually absent from all of the sampled populations. Pure white males held on dark backgrounds in captivity remained white, as they lack the dark chromatophores in their hypodermis needed to change color; off-white males became darker and in some cases lightened up again when transferred back to a white background. Behavioral differences between the sexes may result in differential mortality of white individuals by visual predators.

scholarly journals Ontogenetic changes in the olfactory antennules of the shore crab, Hemigrapsus oregonensis , maintain sniffing function during growth

2015 ◽  
Vol 12 (102) ◽  
pp. 20141077 ◽  
Author(s):  
Lindsay D. Waldrop ◽  
Miranda Hann ◽  
Amy K. Henry ◽  
Agnes Kim ◽  
Ayesha Punjabi ◽  
...  
Keyword(s):  
Particle Image ◽  
Relative Size ◽  
Physical Models ◽  
Shore Crab ◽  
Ontogenetic Changes ◽  
Return Stroke ◽  
Critical Range ◽  
Image Velocimetry ◽  
Flow Through ◽  
Hemigrapsus Oregonensis

Malacostracan crustaceans capture odours using arrays of chemosensory hairs (aesthetascs) on antennules. Lobsters and stomatopods have sparse aesthetascs on long antennules that flick with a rapid downstroke when water flows between the aesthetascs and a slow return stroke when water is trapped within the array (sniffing). Changes in velocity only cause big differences in flow through an array in a critical range of hair size, spacing and speed. Crabs have short antennules bearing dense arrays of flexible aesthetascs that splay apart during downstroke and clump together during return. Can crabs sniff, and when during ontogeny are they big enough to sniff? Antennules of Hemigrapsus oregonensis representing an ontogenetic series from small juveniles to adults were used to design dynamically scaled physical models. Particle image velocimetry quantified fluid flow through each array and showed that even very small crabs capture a new water sample in their arrays during the downstroke and retain that sample during return stroke. Comparison with isometrically scaled antennules suggests that reduction in aesthetasc flexural stiffness during ontogeny, in addition to increase in aesthetasc number and decrease in relative size, maintain sniffing as crabs grow. Sniffing performance of intermediate-sized juveniles was worse than for smaller and larger crabs.

Post-larval mortality of the endoparasitic isopod castrator Portunion conformis (Epicaridea: Entoniscidae) in the shore crab, Hemigrapsus oregonensis, with a description of the host response

Parasitology ◽  
1980 ◽  
Vol 80 (2) ◽  
pp. 211-232 ◽  
Author(s):  
Armand M. Kuris ◽  
George O. Poinar ◽  
Roberta T. Hess
Keyword(s):  
Host Response ◽  
Larval Mortality ◽  
Parasite Population ◽  
Shore Crab ◽  
Differential Mortality ◽  
Multiple Infection ◽  
High Prevalence ◽  
Shore Crabs ◽  
Parasitic Castrator ◽  
Hemigrapsus Oregonensis

SummaryThe shore crabs, Hemigrapsus oregonensis and H. nudus, sometimes kill the female endoparasitic entoniscid isopod, Portunion conformis, a parasitic castrator. Studies of host populations from Baja California, Mexico to Vancouver Island, Canada, show that the incidence of parasitized hosts with dead parasites and the percentage of the parasite population found dead vary markedly with locality but only occasionally with season. Both higher incidences of hosts with dead P. conformis and higher proportions of the total parasite population found dead are associated with (1) high prevalence of parasitism, (2) female hosts and (3) large hosts. Within a host, the proportion of the parasites that are dead is not related to the degree of multiple infection. Typically, either all or none of the parasites in a multiple infection are dead. Supernumerary juvenile parasites do not suffer differential mortality. The developmental stage of the female parasite does not seem to influence the likelihood of death. The presence of dead parasites may not confer an acquired immunity to re-infection. These features suggest that parasite death is typically the result of activation of a successful host defensive process rather than indicative of a defect on the part of the parasites. Parasitized female hosts can regain their reproductive capabilities following death of the parasite. Post-parasitic broods are smaller than normal. Reproductive recovery is presumed to provide the selective pressure favouring evolution of a lethal host response. The host-produced sheath surrounding female parasites is a haemocytic response. Sheaths enclosing dead parasites are thicker and more electron dense than those containing healthy parasites. The sheath of a healthy P. conformis may actually protect the parasite from a more intense host response.

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