Sheltering behavior of terrestrial isopods in grasslands

Abstract. The hypotheses that the sheltering behavior of four species of terrestrial isopods varies in relation to differences in their morphological, physiological, and behavioral adaptations to the terrestrial environment were tested using artificial refugia together with independent estimates of density to derive an index of sheltering activity. (1) Porcellio scaber sheltered significantly more than Platyarthrus hoffmannseggi, Armadillidium vulgare, or Philoscia muscorum, which sheltered the least. (2) There was a decline in the sheltering index (SI) for all four species after the breeding season, continuing through to the autumn and remaining low throughout the winter. (3) Changes in the sheltering behavior of each species in relation to changes in environmental conditions were used to interpret known differences in the position and breadth of their resource utilization curves along a gradient of rabbit grazing intensity. (4) Porcellio scaber sheltered more where the soil was more calcareous, P. muscorum more under the shade of trees, and both P. muscorum and A. vulgare more in grazed than in ungrazed swards. (5) Sheltering behavior was found to be positively correlated to both rainfall and soil temperature the day before sampling for A. vulgare but negatively to rainfall for P. muscorum. There was a positive relationship between the SI for P. scaber and daily air temperature range. (6) Variations in the sheltering behavior of these four species of terrestrial isopod are discussed in the context of their foraging and digestive strategies and in relation to their morphological, physiological, and behavioral adaptations to the terrestrial environment.

[1]  G. Pyke.  Optimal Foraging Theory: A Critical Review , 1984 .

[2]  G. Walter,et al.  Activity patterns and oviposition rates of Aphytis lingnanensis females, a parasitoid of California red scale Aonidiella aurantii: implications for successful biological control , 1999 .

[3]  B. N. K. Davis,et al.  The distribution and diversity of soil fauna , 1977, Pedobiologia.

[4]  M. Hassall.  THE FUNCTIONAL MORPHOLOGY OF THE MOUTHPARTS AND FOREGUT IN THE TERRESTRIAL ISOPOD PHILOSCIA MUSCORUM (SCOPOLI, 1763) , 1977 .

[5]  M. Warburg.  Water Relation and Internal Body Temperature of Isopods from Mesic and Xeric Habitats , 1965, Physiological Zoology.

[6]  A. Yair,et al.  Population dynamics and rôle of Hemilepistus reaumuri (Audouin & Savigny) in a desert ecosystem , 1984 .

[7]  B. M. Lensink.  Distributional ecology of some Acrididae (Orthoptera) in the dunes of Voorne, Netherlands , 1963 .

[8]  J. C. Pollard,et al.  Shelter for lambing in southern New Zealand. II. Sheltering behaviour and effects on productivity , 1999 .

[9]  N. Metcalfe,et al.  Shelter selection in juvenile Atlantic salmon, or why do salmon seek shelter in winter? , 1998 .

[10]  M. Warburg,et al.  Intra-habitat distribution of terrestrial isopods , 1996 .

[11]  W. Topp,et al.  Microorganisms and Cellulose Digestion in the Gut of the Woodlouse Porcellio scaber , 1998, Journal of Chemical Ecology.

[12]  M. Warburg.  Isopods and Their Terrestrial Environment , 1987 .

[13]  M. Warburg,et al.  Seasonal changes on the distribution and abundance of isopod species in different habitats within the Mediterranean region of northern Israel , 1995 .

[14]  M. Hassall,et al.  Shelter site use and secondary sex ratios in the woodlice Armadillidium vulgare and Porcellio scaber (Crustacea: Isopoda) , 1994 .

[15]  E. Odum,et al.  THE EFFECT OF COPROPHAGY ON RETENTION AND BIOELIMINATION OF RADIONUCLIDES BY DETRITUS-FEEDING ANIMALS. , 1969 .

[16]  A. Grant,et al.  Ecotypic differentiation and phenotypic plasticity in reproductive traits of Armadillidium vulgare (Isopoda: Oniscidea) , 2005, Oecologia.

[17]  J. Emlen.  The Role of Time and Energy in Food Preference , 1966, The American Naturalist.

[18]  L. C. Cole.  A Study of the Cryptozoa of an Illinois Woodland , 1946 .

[19]  H. Schmalfuss.  Eco-morphological strategies in terrestrial isopods , 1984 .

[20]  W. C. Allee.  Studies in animal aggregations: Causes and effects of bunching in land isopods , 1926 .

[21]  S. Hopkin,et al.  The structure and function of the digestive system of terrestrial isopods , 1989 .

[22]  E. Edney.  WOODLICE AND THE LAND HABITAT , 1954 .

[23]  M. Hassall,et al.  The role of coprophagy in the feeding strategies of terrestrial isopods , 1982, Oecologia.

[24]  N. Metcalfe,et al.  Experimental demonstration of differences in sheltering behaviour between Icelandic populations of Atlantic salmon (Salmo salar) and Arctic char (Salvelinus alpinus) , 2000 .

[25]  M. Hassall,et al.  The effects of food quality on the life history parameters of the terrestrial isopod (Armadillidium vulgare (Latreille)) , 1983, Oecologia.

[26]  T. Benton,et al.  Estimation of leaf-litter production by dicotyledonous plants in grasslands , 1998 .

[27]  M. Warburg,et al.  The Microclimate in the Habitats of Two Isopod Species in Southern Arizona , 1965 .

[28]  J. Bédard,et al.  Energetic Cost of Man-Induced Disturbance to Staging Snow Geese , 1990 .

[29]  O. H. Paris.  The Ecology of Armadillidium vulgare (Isopoda: Oniscoidea) in California Grassland: Food, Enemies, and Weather , 1963 .

[30]  E. Edney.  Transition from Water to Land in Isopod Crustaceans , 1968 .

[31]  A. Watt.  Studies in the ecology of Breckland. IV. The grass-heath. , 1937 .

[32]  M. Hassall,et al.  Effects of density and spatial heterogeneity on foraging behaviour and fitness correlates of Armadillidium vulgare (Isopoda Oniscidea) , 2005 .

[33]  R. Macarthur,et al.  On Optimal Use of a Patchy Environment , 1966, The American Naturalist.

[34]  S. L. Sutton.  The Biology of Terrestrial Isopods , 1984 .

[35]  L. Lawlor,et al.  A COST OF REPRODUCTION IN A TERRESTRIAL ISOPOD , 1983, Evolution; international journal of organic evolution.

[36]  William Block,et al.  The biology, life cycle and ecophysiology of the Antarctic mite Alaskozetes antarcticus , 1995 .

[37]  H. Hirvonen.  Effects of backswimmer (Notonecta) predation on crayfish (Pacifastacus) young : autotomy and behavioural responses , 1992 .

[38]  M. Hassall,et al.  A modified high-gradient extractor for multiple samples of soil macro-arthropods , 1988, Pedobiologia.

[39]  Larissa Conradt,et al.  Sex differences in weather sensitivity can cause habitat segregation: red deer as an example , 2000, Animal Behaviour.

[40]  D. Kempson,et al.  A new extractor for woodland litter , 1963, Pedobiologia.

[41]  N. Loneragan,et al.  Habitat type and light affect sheltering behaviour of juvenile tiger prawns (Penaeus esculentus Haswell) and success rates of their fish predators , 1995 .

[42]  J. B. Jennings,et al.  Adaptive features of gut structure and digestive physiology in the terrestrial isopod Philoscia muscorum (scopoli) 1763. , 1975, The Biological bulletin.

[43]  A. Robertson,et al.  Energetics of free-ranging large herbivores: when should costs affect foraging behaviour? , 2000 .

[44]  R. Davis.  Effects of weather and habitat structure on the population dynamics of isopods in a dune grassland , 1984 .

[45]  M. Hassall,et al.  The adaptive significance of coprophagous behaviour in the terrestrial isopod Porcellio scaber , 1985 .