Reduced alarm substance cell counts in male and androgen-treated zebra danios (Brachydanio rerio)

1986 ◽  
Vol 64 (2) ◽  
pp. 551-553 ◽  
Author(s):  
R. J. F. Smith
Keyword(s):  
Breeding Season ◽  
Reproductive Cycle ◽  
Epidermal Cells ◽  
Alarm Substance ◽  
Brachydanio Rerio ◽  
Cell Counts ◽  
Alarm Substance Cells

Ostariophysan fish possess large epidermal cells that contain the alarm substance or Schreckstoff characteristic of this group. In some species these alarm substance cells are retained throughout the reproductive cycle; in others they are completely absent from the epidermis during the breeding season in males only or in both sexes. Zebra danios represent a fourth category: males have fewer alarm-substance cells than do females and treatment with 17α-methyltestosterone leads to a further reduction, but not complete absence, of alarm substance cells. Treating females with 17α-methyltestosterone reduced the number of alarm substance cells in their epidermis.

Effect of hormone treatments on alarm substance cell counts in the pearl dace, Semotilus margarita

1986 ◽  
Vol 64 (2) ◽  
pp. 291-295 ◽  
Author(s):  
Jeaniene D. Smith ◽  
R. J. F. Smith
Keyword(s):  
Pimephales Promelas ◽  
Mucous Cell ◽  
Cell Loss ◽  
Alarm Substance ◽  
Androgen Treatment ◽  
Cell Counts ◽  
Sexual Characteristics ◽  
Alarm Substance Cells ◽  
The Difference ◽  
Induced Changes

The seasonal loss of alarm substance cells that normally occurs in breeding male and female pearl dace, Semotilus margarita, could not be induced by treatment with androgen, estrogen, salmon gonadotropin, or prolactin. Treatment with carp pituitary did lead to a significant reduction in alarm substance cell numbers. Androgen treatment induced changes in tuberculation and mucous cell counts. Salmon gonadotropin and carp pituitary increased breeding colouration. Prolactin treatment increased mucous cell counts. The lack of response of pearl dace alarm substance cells to androgen contrasts with the situation in fathead minnows, Pimephales promelas, where seasonal alarm substance cell loss is under androgen control. The difference may reflect differences in the annual cycle of secondary sexual characteristics.

Male fathead minnows (Pimephales promelas Rafinesque) retain their fright reaction to alarm substance during the breeding season

1976 ◽  
Vol 54 (12) ◽  
pp. 2230-2231 ◽  
Author(s):  
R. J. F. Smith
Keyword(s):  
Breeding Season ◽  
Pimephales Promelas ◽  
Field Tests ◽  
Alarm Substance ◽  
Skin Extract ◽  
Fathead Minnows ◽  
Fright Reaction ◽  
Alarm Substance Cells

In laboratory and field tests, breeding male fathead minnows respond to conspecific skin extract with a fright reaction despite their own seasonal loss of alarm substance cells. Their fright reaction is facilitated by the presence of other fatheads.

Epidermal club cells are not linked with an alarm response in reedfish, Erpetoichthys (= Calamoichthys) calabaricus

1987 ◽  
Vol 65 (8) ◽  
pp. 2057-2061 ◽  
Author(s):  
D. M. Hugie ◽  
R. J. F. Smith
Keyword(s):  
Alarm Pheromone ◽  
Cross Reaction ◽  
Alarm Substance ◽  
Skin Extract ◽  
Feeding Response ◽  
Brachydanio Rerio ◽  
Alarm Response ◽  
Fright Reaction ◽  
Club Cells ◽  
Alarm Substance Cells

Club cells in the epidermis of reedfish, Erpetoichthys (= Calamoichthys) calabaricus (Pisces, Polypteriformes), are morphologically similar, perhaps homologous, to the "alarm substance cells" found in the skin of cypriniform fishes. Cypriniforms perform a fright reaction when they detect chemicals released from the damaged alarm substance cells of conspecifics. We examined the response of reedfish to conspecific skin extract and checked for a cross reaction to reedfish extract by a cypriniform fish, the zebra danio, Brachydanio rerio. Reedfish responded to conspecific skin extract with an increase in activity but this response did not resemble a fright reaction. Zebra danios responded to reedfish extract with a feeding response. We conclude that reedfish do not show a fright reaction to the skin extract of conspecifics. This suggests that if cypriniform alarm substance cells are homologous to reedfish club cells, their alarm pheromone function is a secondary adaptation.

THE FRIGHT REACTION IN NORTH AMERICAN FISH

1963 ◽  
Vol 41 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Wolfgang Pfeiffer
Keyword(s):  
North American ◽  
Alarm Substance ◽  
Fish Skin ◽  
Cyprinid Species ◽  
Fright Reaction ◽  
Skin Physiology ◽  
Alarm Substance Cells

The fright reaction was found in five species of North American Cyprinidae including the predaceous northern squawfish, and in two species of Catostomidae. The threshold for Cyprinidae is 1/1000 N ("normal") extract or lower, that for Catostomidae at least a 1/100 N extract. The cyprinid species reacted very strongly to extract from other Cyprinidae but less strongly to catostomid extract; catostomid species reacted strongly to extract from other Catostomidae but less strongly to cyprinid extract. Salmon extract did not produce any reaction in Cyprinidae or Catostomidae. The epidermis of all species studied contained alarm substance cells; the epidermis of the Catostomidæ was very similar to that of the Cyprinidae. There was a relationship between number and size of the alarm substance cells (histology) and the quantity of alarm substance in the fish skin (physiology). The ability to respond to the alarm substance first appeared in young redside shiners at an age of 42 days, in young zebrafish at an age of 32 days, when the fish were kept at 26 °C.

The Distribution of Fright Reaction and Alarm Substance Cells in Fishes

Copeia ◽  
1977 ◽  
Vol 1977 (4) ◽  
pp. 653 ◽  
Author(s):  
Wolfgang Pfeiffer
Keyword(s):  
Alarm Substance ◽  
Fright Reaction ◽  
Alarm Substance Cells

Population ecology of the Intertidal Anemone Actinia tenebrosa II Geographical distribution, synonymy, reproductive cycle and fecundity

1979 ◽  
Vol 27 (2) ◽  
pp. 273 ◽  
Author(s):  
JR Ottaway
Keyword(s):  
New Zealand ◽  
Geographical Distribution ◽  
Breeding Season ◽  
Reproductive Cycle ◽  
Population Ecology ◽  
Adult Population ◽  
Gonad Development ◽  
Reproductive Mode ◽  
The Other

Synonymy and geographical distribution of A. tenebrosa are discussed. Reproductive cycle and fecundity were examined between 1972 and 1975 inclusive at Kaikoura, New Zealand. At any one time, up to 77% of the adult population developed gonads and 20-94% of adults were brooding young. The main periods of gonad development, November-April inclusive, coincided with the warmest annual sea temperatures. Over 99.4% of brooded embryos dissected from 1851 adults were tentaculate young; the rest were planulae. It is suggested that the normal reproductive mode of the observed population is cross-fertilizing labile gonochorism, in which adults change from one sex to the other within each breeding season. Brooding adults would therefore be the maternal parents of their brooded embryos, even though subsequently the brooders would appear to be asexual or could become functional males.

The reproductive cycle of the firetail gudgeon, Hypseleotris galii II. Seasonal histological changes in the testes

1973 ◽  
Vol 21 (1) ◽  
pp. 67 ◽  
Author(s):  
NJ Mackay
Keyword(s):  
Water Temperature ◽  
Breeding Season ◽  
Reproductive Cycle ◽  
Meiotic Division ◽  
Steroid Biosynthesis ◽  
Histological Changes ◽  
Late Autumn

Seasonal histological changes in the testis of H.galii are described. Spermatogenesis follows the cystic pattern common in anamniotes. Mitotic increase in spermatogonia occurs in late autumn, when photoperiod and water temperature are falling. The meiotic division of spermatocytes and subsequent changes of spermatogenesis are initiated when photoperiod and water temperature are rising and continue through the breeding season (November-January) until March, when water temperature begins to fall rapidly. The possible role of cholesterol-positive lobule boundary cells in steroid biosynthesis is discussed.

scholarly journals Epidermal ‘alarm substance’ cells of fishes maintained by non-alarm functions: possible defence against pathogens, parasites and UVB radiation

2007 ◽  
Vol 274 (1625) ◽  
pp. 2611-2619 ◽  
Author(s):  
Douglas P Chivers ◽  
Brian D Wisenden ◽  
Carrie J Hindman ◽  
Tracy A Michalak ◽  
Robin C Kusch ◽  
...  
Keyword(s):  
Public Information ◽  
Alarm Substance ◽  
Alarm Cues ◽  
Uvb Radiation ◽  
Ecological Role ◽  
Saprolegnia Ferax ◽  
Predator Prey ◽  
Cell Production ◽  
Saprolegnia Parasitica ◽  
Alarm Substance Cells

Many fishes possess specialized epidermal cells that are ruptured by the teeth of predators, thus reliably indicating the presence of an actively foraging predator. Understanding the evolution of these cells has intrigued evolutionary ecologists because the release of these alarm chemicals is not voluntary. Here, we show that predation pressure does not influence alarm cell production in fishes. Alarm cell production is stimulated by exposure to skin-penetrating pathogens (water moulds: Saprolegnia ferax and Saprolegnia parasitica ), skin-penetrating parasites (larval trematodes: Teleorchis sp. and Uvulifer sp.) and correlated with exposure to UV radiation. Suppression of the immune system with environmentally relevant levels of Cd inhibits alarm cell production of fishes challenged with Saprolegnia . These data are the first evidence that alarm substance cells have an immune function against ubiquitous environmental challenges to epidermal integrity. Our results indicate that these specialized cells arose and are maintained by natural selection owing to selfish benefits unrelated to predator–prey interactions. Cell contents released when these cells are damaged in predator attacks have secondarily acquired an ecological role as alarm cues because selection favours receivers to detect and respond adaptively to public information about predation.

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