ZOOLOGICAL SCIENCE 5: 443-448 (1988) ? 1988 Zoological Society of Japan Feeding Responses of Pacific Snappers (genus Lutjanus) to the Yellow-bellied Sea Snake (Pelamis platurus) Paul J. Weldon Department of Biology, Texas A & M University, College Station, TX 77843, U.S.A. ABSTRACT ? Previous studies indicate that Pacific fishes refuse to attack the yellow-bellied sea snake (Pelamis platurus). Visual and non-visual cues are thought to be used to identify this snake. Three species of Pacific snappers -Lutjanus aratus, L. argentiventris, and L. guttatus -were tested for reactions to pieces or extracts of P. platurus. Snappers presented with carcass pieces of a variety of stimulus animals regurgitated P. platurus more than others; one experiment was inconclusive. Snappers presented in darkness with pieces of stimulus animals attached to clips removed fewer P. platurus pieces than those of other species. Pieces of P. platurus skin were regurgitated more frequently, and removed from clips less frequently, than were pieces of skinned carcass or control animals. Large pieces (5.0 g) of P. platurus were regurgitated and rejected more often than were small pieces (1.3 g). Snappers regurgitated and rejected fish pieces treated with a chloroform: methanol extract of P. platurus more than pieces treated with solvent alone. This study indicates that snappers detect chemicals from this snake. INTRODUCTION The yellow-bellied sea snake (Pelamis platurus) is found from the west coast of Central America to the east coast of Africa [1]. Although predation pressure in tropical Pacific waters is notoriously intense [2], no species has been observed to eat this highly venomous, pelagic serpent. A couple of presumed predators (rather than scavengers) have regurgitated P. platurus [3, 4], but stomach con- tent analyses of a variety of predatory fishes -457 fishes representing 25 species from Panama [1], 186 dolphins (Stenella spp.) and 79 tuna (Thunnus albacores) from the eastern Pacific [5], approx- imately 1000 sharks (mostly Carcharhinus falcifor- mis) from Baja California to Costa Rica (S. Kato, pers. comm.), and thousands of sharks from around Australia [6, 7] -failed to indicate this snake's remains. Heatwole [6] inspected 19 species of marine snakes in Australian waters for pre- dator-induced injuries and found that P. platurus was the only amply represented species that lacked any sign of attacks by fishes. Wounds in P. Accepted October 20, 1987 Received February 26, 1987 platurus from the eastern Pacific have been documented, but at least some of these appear to be man-made rather than caused by would-be predators [8]. Observations of the reactions of birds and predatory fishes to P. platurus indicate that this snake is avoided. Naive herons and egrets in Panama presented with several eels, a terrestrial snake, and P. platurus fled only from the latter [9]. A variety of teleost and elasmobranch fishes refused to attack P. platurus or regurgitated pieces of this snake if they were ingested [10]. The cues by which potential predators recognize sea snakes have not been studied systematically, but several authors suggest that the conspicuous yellow (ventral) and black (dorsal) coloration of P. platurus acts as an aposematic signal [1,6, 10, 11]. Rubinoff and Kropach [10] state that other cues also may be involved since snake pieces were rejected by Pacific fishes even after the snakes' color patterns had been modified with marking pens, when snakes were skinned, and when snake pieces were wrapped in squid flesh. Rubinoff and Kropach [10] suggest that fishes identify snakes by chemical cues. This study examines the feeding reactions of
Reference added about 22 hours ago
Viewer
blog comments powered byPage loaded in 0.10334 seconds
ZOOLOGICAL SCIENCE 5: 443-448 (1988) ? 1988 Zoological Society of Japan Feeding Responses of Pacific Snappers (genus Lutjanus) to the Yellow-bellied Sea Snake (Pelamis platurus) Paul J. Weldon Department of Biology, Texas A & M University, College Station, TX 77843, U.S.A. ABSTRACT ? Previous studies indicate that Pacific fishes refuse to attack the yellow-bellied sea snake (Pelamis platurus). Visual and non-visual cues are thought to be used to identify this snake. Three species of Pacific snappers -Lutjanus aratus, L. argentiventris, and L. guttatus -were tested for reactions to pieces or extracts of P. platurus. Snappers presented with carcass pieces of a variety of stimulus animals regurgitated P. platurus more than others; one experiment was inconclusive. Snappers presented in darkness with pieces of stimulus animals attached to clips removed fewer P. platurus pieces than those of other species. Pieces of P. platurus skin were regurgitated more frequently, and removed from clips less frequently, than were pieces of skinned carcass or control animals. Large pieces (5.0 g) of P. platurus were regurgitated and rejected more often than were small pieces (1.3 g). Snappers regurgitated and rejected fish pieces treated with a chloroform: methanol extract of P. platurus more than pieces treated with solvent alone. This study indicates that snappers detect chemicals from this snake. INTRODUCTION The yellow-bellied sea snake (Pelamis platurus) is found from the west coast of Central America to the east coast of Africa [1]. Although predation pressure in tropical Pacific waters is notoriously intense [2], no species has been observed to eat this highly venomous, pelagic serpent. A couple of presumed predators (rather than scavengers) have regurgitated P. platurus [3, 4], but stomach con- tent analyses of a variety of predatory fishes -457 fishes representing 25 species from Panama [1], 186 dolphins (Stenella spp.) and 79 tuna (Thunnus albacores) from the eastern Pacific [5], approx- imately 1000 sharks (mostly Carcharhinus falcifor- mis) from Baja California to Costa Rica (S. Kato, pers. comm.), and thousands of sharks from around Australia [6, 7] -failed to indicate this snake's remains. Heatwole [6] inspected 19 species of marine snakes in Australian waters for pre- dator-induced injuries and found that P. platurus was the only amply represented species that lacked any sign of attacks by fishes. Wounds in P. Accepted October 20, 1987 Received February 26, 1987 platurus from the eastern Pacific have been documented, but at least some of these appear to be man-made rather than caused by would-be predators [8]. Observations of the reactions of birds and predatory fishes to P. platurus indicate that this snake is avoided. Naive herons and egrets in Panama presented with several eels, a terrestrial snake, and P. platurus fled only from the latter [9]. A variety of teleost and elasmobranch fishes refused to attack P. platurus or regurgitated pieces of this snake if they were ingested [10]. The cues by which potential predators recognize sea snakes have not been studied systematically, but several authors suggest that the conspicuous yellow (ventral) and black (dorsal) coloration of P. platurus acts as an aposematic signal [1,6, 10, 11]. Rubinoff and Kropach [10] state that other cues also may be involved since snake pieces were rejected by Pacific fishes even after the snakes' color patterns had been modified with marking pens, when snakes were skinned, and when snake pieces were wrapped in squid flesh. Rubinoff and Kropach [10] suggest that fishes identify snakes by chemical cues. This study examines the feeding reactions of
Feeding Responses of Pacific Snappers (genus Lutjanus) to the Yellow-bellied Sea Snake (Pelamis platurus) : Behavior Biology
Reference added about 22 hours ago
Viewer
blog comments powered byPage loaded in 0.10334 seconds
Source: http://biostor.org/reference/106992
Nastia Liukin Gabby Douglas hair Kayla Harrison Mars landing Gabby Douglas John Orozco Garrett Reid
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.