Water UptakeviaTwo Pairs of Specialized Legs inLigia exotica(Crustacea, Isopoda)

Abstract

When individuals of Ligia exotica were exposed to dry environments, their weight decreased within 3 h to 90% of the initial weight. When the animals were subsequently presented with wet paper, pereiopods VI and VII were firmly apposed and moved around until their tips were stationary for some seconds. Subsequently the pleopods became soaked in water and the body weight recovered. Morphological observations revealed hollow structures on the surface of the dactylus and propodus of pereiopods VI and VII, and a series of thin cuticular protrusions, oriented in several parallel lines, from the propodite to the ischiopodite of pereiopod VI and on the basipodite of pereiopod VII. The width between the parallel lines varied little, but the total width of the regular lines increased linearly with increasing body size. When isolated caudal pereiopods were immersed, beginning at the distal end, in water, water flowed along pereiopod VI as far as the proximal end of the ischiopodite, but water flow along pereiopod VII occurred only in conjunction with the basipodite. This means that water uptake with the legs requires both pereiopods VI and VII and can be achieved only when these legs are closely apposed.

Capillary Rise on Legs of a Small Animal and on Artificially Textured Surfaces Mimicking Them

“…To survive it absorbs water from the sea through its legs [29]. On the outer surface of the leg there is a path for water transport covered with a remarkable array of small blades of micron scales as in Fig.…”

Pollution of radiocesium and radiosilver in wharf roach (Ligia sp.) by the Fukushima Dai-ichi Nuclear Power Plant accident

“…As semi-terrestrial organisms, wharf roaches have to actively absorb water via their specialized legs from droplets or puddles [12]. If wharf roaches absorb water from contaminated sediments, this water uptake pattern may accelerate the accumulation of radionuclides and thereby contribute to their high radionuclide concentrations.…”

“…Abundant wharf roaches can be found on the seashore among pilings, beach fortifications, jetties, and rocks in most estuary and coastal areas of Japan [11,12]. Owing to some of their ecophysiological characteristics, these crustaceans are highly constrained throughout their life cycle to remain on the same beach [10], and thus may serve as a good bioindicator of radioactive contamination of their habitats [13].…”

In Vivo Ion Fluxes across the Eggs ofArmadillidium vulgare(Oniscidea: Isopoda): The Role of the Dorsal Organ

“…Over the period from 400 to 800 niin, means ± SHM were -13.2 ± 2.0 (anterior pole), -10.6 ± 1.9 (posterior pole), and -46.2 ± 4.6 (dorsal organ). The ability of these genera to provision the marsupial fluid from external water sources (Hoese 1984;Horiguchi et al 2007) may compensate for the apparently minimal development of the dorsal organ. In the more terrestrial oniscidean lineages, the hypertrophy of the dorsal organ can be seen as part of a suite of adaptations including the closed marsupium, maternal regulation of marsupial fluid, and reduced permeability (Carefoot 1993; Surbida and Wright 2001 ), allowing for tighter physiological control of the embryo environment and helping to explain their extensive speciation and ecological diversity on land.…”