The environmental physiology of Bufo bufo L. and Bufo calamita Laur. tadpoles.
Using spawncollected from the north ~rseyside sand dune system, the
effects of tenperature on growth, developrent, rretabolism and
rretamorphosis in B. bufo and B. calamita tadpoles were investigated,
together with a limited study on the effects of L-thyroxine. The
effects of density on growth, developteI1t and rretarnorphosis were
examined. Physiological and behavioural effects of B. bufo tadpoles on
B. calamita tadpoles were also studied.
B. calamita spawnand tadpoles survive at higher temperatures than
B. bufo. Below20°CB. bufo spawn, and below 15°Ctheir t.adpcl.es,
develop at a greater rate than B. calamita. B. calamita spawnand
tadpoles' growth and developrent is faster at higher temperatures.
B. calamita tadpoles have higher rretabolic rates than B. bufo across
the terrperature range 15-30°C. Faster rates of rretabolism and
developnent in B. calamita result in smaller tadpoles and toadlets than
B. bufo. B. calamita mayconpensate for this with increased
rretamorphic efficiency in tenns of energy. It is speculated that
differences in tadpole thyroid physiology could account for observed
differences. ~tamorphic efficiency was greatest, and rates of
developrent and growth maximised/at the tadpoles' preferred body
Increased density reduced growth-and developteI1t of tadpoles, but
influenced different stages in the two species. ~tamorphosis in
all B. bufo tadpoles was delayed, whereas in B. calamita a proportion
of the population rretarnorphosedapparently unaffected by increased
The responses of tadpoles to temperature and density were related to
the species' prefered spawningenvironrrents.
In the presence of B. bufo tadpoles, B. calamita growth, developrent
and rretabolism was suppressed. The pattern of developrent and timing
of rretamorphosis in B. calamita becamesimilar to that of B. bufo.
Inhibition was not relieved by L-thyroxine, and did not effect tadpole
behaviour. Mass specific food consurrption was increased. It is
speculated that the i.nh.ibitor is a parasite or a substance which