EVALUATION OF THE TOXICITY OF EGGS, HATCHLINGS AND TADPOLES OF THE INTRODUCED TOAD BUFO-MARINUS (ANURA, BUFONIDAE) TO NATIVE-AUSTRALIAN AQUATIC PREDATORS
Mr. Crossland et Ra. Alford, EVALUATION OF THE TOXICITY OF EGGS, HATCHLINGS AND TADPOLES OF THE INTRODUCED TOAD BUFO-MARINUS (ANURA, BUFONIDAE) TO NATIVE-AUSTRALIAN AQUATIC PREDATORS, Australian journal of ecology, 23(2), 1998, pp. 129-137
The early life history stages of anurans in the Family Bufonidae often
possess chemicals that are noxious or toxic to predators. Predators w
ith no evolutionary history of exposure to bufonids may be particularl
y susceptible to these toxins. We conducted a series of laboratory exp
eriments to investigate the toxic effects of eggs, hatchlings and tadp
oles of the introduced toad, Bufo marinus (Linnaeus), on native Austra
lian aquatic predators. There was considerable interspecific and intra
specific variation in these effects. Bufo marinus were highly toxic to
some predator species, but were readily consumed by other species wit
hout apparent in effect. Interspecific variation in toxic effects was
not related to predator feeding mode or the number of B. marinus inges
ted by predators, and there was no clear pattern of distribution of vu
lnerability among species within higher taxa. Intraspecific variation
in responses to toxins may result from individual variation in the res
istance of predators to B. marinus toxins, or from individual variatio
n in toxicity among B. marinus. Some native species adversely affected
by B. marinus appeared unable to detect and avoid B. marinus toxins.
This may result from a general inability to assess the toxicity of foo
d items or from a lack of evolutionary exposure to B. marinus toxins.