Is the aestivation of the earthworm<i>Hormogaster elisae</i>a paradiapause?

Cosín, Darío J. Díaz; Ruiz, M. Pilar; Ramajo, Marta; Garcı́a-Gutiérrez, Miguel

doi:10.1111/j.1744-7410.2006.00057.x

Cited by 22 publications

(17 citation statements)

References 10 publications

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“…Branchiobdellidan aestivation can be entered and broken quickly (within minutes), it can be entered and broken multiple times (i.e., temporary), but it cannot last for extended periods (>~20 min). These features are consistent with a shallow, facultative quiescence rather than a deep diapause (criteria from Denlinger 2002;Díaz Cosín et al 2006). Enhanced water conservation during coiling suggests C. mesochoreus uses quiescence as an adaptive strategy for maintaining water balance in the short-term, but not for longterm survival in the absence of free water resources.…”

Section: Discussionsupporting

confidence: 66%

“…Desiccation prompts the worms to enter a non-feeding, immobile state, and they are resurrected (activated) by adding water to them. Coiling with a water resurrection is a common response for an annelid, having been described in free-living annelids, oligochaetes, and leeches triggered by soil dryness (Valle et al 1999;Jiménez et al 2000;Díaz Cosín et al 2006) and it is associated with water conservation in soil nematodes (Wharton and Barclay 1993;Wharton 1996;Treonis and Wall 2005;Wharton et al 2008;Perry et al 2012). In fact, the water loss rate profile of C. mesochoreus fits the typical anhydrobiotic 'permeability slump' in nematodes (Wharton and Barclay 1993;Wharton 1996;Wharton et al 2008), which features a biphasic, two-component curve (discontinuous slope) as the worm shifts from vermiform (high water loss) to coiled form (low water loss) and back again to vermiform (high water loss).…”

Section: Discussionmentioning

confidence: 97%

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Hygric stresses and strategies in maintaining the association between crayfish and ectosymbiotic worms across vastly different environments

et al. 2016

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Crayfish and their ectosymbiotic worms may be a valuable model system for studying strategies to maintain symbiotic relationships strained by host-induced environmental shifts. Ectosymbiotic branchiobdellidan worms are thought to be dependent on crayfish hosts for reproduction. However, many crayfish species leave surface waters to excavate and reside in subterranean burrows. During this semi-terrestrial phase, crayfish are frequently out of water, subjecting their associated worms to desiccation. Water balance characteristics of Cambarincola mesochoreus, an ectosymbiont of Procambarus clarkii, were examined to elucidate strategies for surviving emersion while maintaining host associations. Emersed worms were characterized by a high water loss rate and low tolerance for dehydration. A lack of direct water contact eventually prompted a coiled, immobile dormant state where water loss was temporarily suppressed. This dormant state was broken by addition of water and re-entered by subsequent emersion. Neither group effects by clustering of many worms, nor water vapor absorption were utilized as mechanisms to increase desiccation hardiness. When crayfish leave surface or subterranean water, worm survival while maintaining host contact is likely facilitated by facultative quiescence. However, this strategy only allows for survival during relatively short-term, cyclic bouts of emersion. Survival of longer-term emersion periods would require worms to leave hosts and remain behind in surface or subterranean water. These strategies likely incur counterbalancing trade-offs: increased mortality but maintenance of host association versus increased survival but temporary or permanent loss of host association and sites for reproduction.

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Section: Discussionsupporting

confidence: 66%

Section: Discussionmentioning

confidence: 97%

Hygric stresses and strategies in maintaining the association between crayfish and ectosymbiotic worms across vastly different environments

et al. 2016

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“…To protect themselves from these environmental adversities, diapausing animals minimize exchanges with their environment by producing cocoons [e.g. Nemertea and Annelida (Càceres, 1997;Diaz Cosin et al, 2006)] or a thicker cuticle [e.g. dauer larva of nematodes (Càceres, 1997)], or remaining within the cuticle of the previous instar [e.g.…”

Section: Discussionmentioning

confidence: 99%

Diapause in tardigrades: a study of factors involved in encystment

Guidetti¹,

Boschini

Altiero

et al. 2008

Journal of Experimental Biology

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SUMMARYStressful environmental conditions limit survival, growth and reproduction, or these conditions induce resting stages indicated as dormancy. Tardigrades represent one of the few animal phyla able to perform both forms of dormancy: quiescence and diapause. Different forms of cryptobiosis (quiescence) are widespread and well studied, while little attention has been devoted to the adaptive meaning of encystment (diapause). Our goal was to determine the environmental factors and token stimuli involved in the encystment process of tardigrades. The eutardigrade Amphibolus volubilis, a species able to produce two types of cyst (type 1 and type 2), was considered. Laboratory experiments and long-term studies on cyst dynamics of a natural population were conducted. Laboratory experiments demonstrated that active tardigrades collected in April produced mainly type 2 cysts, whereas animals collected in November produced mainly type 1 cysts, indicating that the different responses are functions of the physiological state at the time they were collected. The dynamics of the two types of cyst show opposite seasonal trends: type 2 cysts are present only during the warm season and type 1 cysts are present during the cold season. Temperature represents the environmental factor involved in induction, maintenance and termination of the cyst. We also obtained evidence that A. volubilis is able to perform both diapause and cryptobiosis, even overlapping the two phenomena. The induction phase of tardigrade encystment can be compared to the induction phase of insect diapause, also indicating an involvement of endogenous factors in tardigrade encystment. As in insect diapause, tardigrade encystment can be considered a diapausing state controlled by exogenous and endogenous stimuli.

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“…This species is adapted to sandy soils that are poor in organic matter. Hence, it can form monospecific populations in poorer soils where other earthworm species cannot survive (Hernández et al 2007), and when conditions are adverse, such as lack of rain and dryness of soil, it can undergo paradiapause (Díaz Cosín et al 2006). All these make H. elisae a potential beneficiary of global warming.…”

mentioning

confidence: 99%