Results 141 to 150 of about 465 (167)

Differences in energy allocation during growth and reproduction by semelparous and iteroparous Nephelopsis obscura (Erpobdellidae)

Archiv Für Hydrobiologie, 1996
In the laboratory the freshwater invertebrate predator Nephelopsis, obscura fed ad libitum at 20°C exhibited a double-sigmoid growth pattern, with a few individuals exhibiting a single sigmoid growth pattern before death. The amount of food ingested fluctuated but two significant decreases in ingestion occurred during each sigmoid growth cycle ...
Ronald W. Davies, E. Dratnal
exaly   +2 more sources

THE LIFE CYCLE AND PRODUCTION OF THE LEECH ERPOBDELLA OCTOCULATA (L.) (HIRUDINEA: ERPOBDELLIDAE) IN A LAKE DISTRICT STREAM

The Journal of Animal Ecology, 1973
Two species of leeches, Erpobdeila octoculata (L.) and Glossiphonia complanata (L.), were found in the Wilfin Beck, a small stony stream in the English Lake District. The population of G. complanata was very small and no detailed study of this species could be made.
J. M. Elliott
semanticscholar   +2 more sources

The Diel Activity Pattern, Drifting and Food of the Leech Erpobdella octoculata (L.) (Hirudinea: Erpobdellidae) in a Lake District Stream

Journal of Animal Ecology, 1973
J. M. Elliott
exaly   +2 more sources

A revision of the British leeches of the family Erpobdellidae, with a description of Dina lineata (O. F. Müller, 1774), a leech new to British fauna

Proceedings of the Zoological Society of London, 2009
K H Mann
exaly   +2 more sources

Histopathology of hyperoxia in Nephelopsis obscura (Hirudinoidea: Erpobdellidae)

Journal of Invertebrate Pathology, 1987
Abstract Small (10–15 mg) and large (300–350 mg) Nephelopsis obscura in the laboratory were exposed to supersaturated oxygen (250–300% saturation) at 4° and 15°C simulating winter and summer field conditions in southern Alberta. The results for both weight groups at both temperatures were very similar.
R.N. Singhal, Ronald W. Davies
openaire   +1 more source

The influence of temperature on the depth distribution of sympatric Erpobdellidae (Hirudinoidea)

Canadian Journal of Zoology, 1987
Inter- and intra-specific differences in the behavioral responses of two sympatric Erpobdellidae, Nephelopsis obscura and Erpobdella punctata, to overall water temperature change and thermal gradients were investigated in the laboratory. The results are compared with the seasonal migratory patterns recorded in lentic field habitats.
T. E. Gates, Ronald W. Davies
openaire   +1 more source

Cosexuality in the Leech,Nephelopsis obscura(Erpobdellidae)

International Journal of Invertebrate Reproduction and Development, 1988
Summary Hermaphroditism of the erpobdellid leach Nephelopsis obscura is described on the basis of macroscopic and histological studies of the gonads. Perivitellogenic cells (female primordial germ cells) proliferate from the septa of segments XII and XIII in individuals of 26–30 mg and spermatogenic cells from segments XII to XIII of 20–25 mg specimens.
Ronald W. Davies, R. N. Singhal
openaire   +1 more source

Dina kobakhidzei sp. nov. (Hirudinea: Erpobdellidae): a new Caucasian cave leech from Georgia

Zoology in the Middle East
A new leech species, Dina kobakhidzei sp. nov., discovered in the Tskhrajvari I Cave in the Racha-Lechkhumi and Lower Svaneti region of western Georgia, is described and illustrated.
C. Grosser, Eteri Maghradze, S. Barjadze
semanticscholar   +1 more source

Effects of anoxia and hyperoxia on the neurons in the leech Nephelopsis obscura (Erpobdellidae): Ultrastructural studies

Journal of Invertebrate Pathology, 1988
Abstract The ultrastructure of neurons in the leech Nephelopsis obscura exposed to anoxic or hyperoxic conditions in the laboratory were studied and compared with neurons in normoxic control animals. Oxygen stress alters the shape and structure of membranous organelles, including mitochondria, endoplasmic reticulum, and Golgi complex, and also ...
Ram N. Singhal, Harvey B. Sarnat, Ronald W. Davies   +2 more
openaire   +1 more source

Effects of anoxia, hyperoxia, and salinity on neurons in the leech Nephelopsis obscura (Erpobdellidae): RNA redistribution by fluorescence histochemistry

Journal of Invertebrate Pathology, 1989
The histochemical distribution of cytoplasmic RNA in ganglion cells of the freshwater leech Nephelopsis obscura has been studied using the fluorochrome acridine orange as a marker of nucleic acids. Two series of experiments, employing 50 adult animals, involved changes in oxygen tension in the water and changes in salinity. Normal leech neurons exhibit
R N, Singhal, H B, Sarnat, R W, Davies
openaire   +2 more sources