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

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.


1976 ◽  
Vol 54 (12) ◽  
pp. 2230-2231 ◽  
Author(s):  
R. J. F. Smith

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.



1963 ◽  
Vol 41 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Wolfgang Pfeiffer

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.



Copeia ◽  
1977 ◽  
Vol 1977 (4) ◽  
pp. 653 ◽  
Author(s):  
Wolfgang Pfeiffer


1986 ◽  
Vol 64 (2) ◽  
pp. 551-553 ◽  
Author(s):  
R. J. F. Smith

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.



2004 ◽  
Vol 82 (3) ◽  
pp. 407-415 ◽  
Author(s):  
Angélique Dupuch ◽  
Pierre Magnan ◽  
Lawrence M Dill

The northern redbelly dace, Phoxinus eos (Cope, 1862), is subject to predation by brook trout, Salvelinus fontinalis (Mitchill, 1814), in Canadian Shield lakes, particularly when individuals migrate to the pelagic zone at sunset to feed on zooplankton and fish shoals break up into single individuals. The objectives of the present study were to (i) determine whether northern redbelly dace react to skin extracts from conspecifics and thus potentially use chemical alarms to detect predators in nature, (ii) characterize the fright reaction in northern redbelly dace under different concentrations of alarm substance, and (iii) estimate the active space of the alarm substance in this species. Northern redbelly dace responded to skin extracts of conspecifics with a series of antipredator behaviours. The dace moved closer to the substrate and away from the area where the alarm substance was injected, increased both the cohesion and polarization of their schools, and performed more dashing and freezing behaviours. The observed responses were closely correlated with the concentration of the skin extract solution, suggesting that individuals could use this sensitivity to different concentrations of alarm substance to estimate the risk of predation in nature. The dilution experiment allowed us to estimate that 1 cm2 of northern redbelly dace skin contains enough alarm substance to generate a response of individuals in 110 558 L of water, which corresponds to a cube with sides of approximately 4.8 m. Indirect evidence suggests that the northern redbelly dace could use chemical alarm cues to assess the risk of predation by brook trout in nature.



Behaviour ◽  
2001 ◽  
Vol 138 (10) ◽  
pp. 1205-1214 ◽  
Author(s):  
Gilson Volpato ◽  
Percília Giaquinto

AbstractAlthough the skin of an injured conspecific releases alarm substance in some fish species, it has been shown that such damage induces feeding behaviour rather than an alarm reaction under conditions of food scarcity. We studied chemical communication associated with this paradox in a Brazilian catfish, the pintado (Pseudoplatystoma coruscans). In preliminary tests pintado were confirmed to demonstrate an alarm reaction to conspecific skin extract. In the experiment we investigated whether skin extract of pintado induces either alarm response (panic or alert component) or feeding in hungry conspecifics. Fish feed-deprived for eight days and fed control fish were exposed to either conspecific skin extract or distilled water (as a control). Alarm reaction was restricted to the skin extract treatment and occurred in the fish irrespective of their hunger state, but the components of this response were significantly affected by hungry. Fed fish showed a complete alarm reaction (dashing and freezing behaviours). Feed-deprived fish exhibited only part of this biphasic response, the dashing component. We conclude that chemicals from injured fish elicit an alarm reaction, which is partially inhibited by feeding motivation.



2007 ◽  
Vol 274 (1625) ◽  
pp. 2611-2619 ◽  
Author(s):  
Douglas P Chivers ◽  
Brian D Wisenden ◽  
Carrie J Hindman ◽  
Tracy A Michalak ◽  
Robin C Kusch ◽  
...  

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.



1986 ◽  
Vol 64 (2) ◽  
pp. 291-295 ◽  
Author(s):  
Jeaniene D. Smith ◽  
R. J. F. Smith

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.



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