KIN-MEDIATED MORPHOGENESIS IN FACULTATIVELY CANNIBALISTIC TADPOLES.

Area of Science:

• Evolutionary Biology
• Developmental Biology
• Behavioral Ecology

Background:

• Inclusive fitness theory explains kin-directed altruism.
• Morphogenesis can be influenced by environmental factors, including social context.
• Some species exhibit polyphenism, developing distinct phenotypes based on environmental cues.

Purpose of the Study:

• To investigate the effect of kinship on the development of a cannibalistic carnivore phenotype in spadefoot toad tadpoles.
• To determine if consanguinity influences the facultative expression of alternative phenotypes.
• To test the role of waterborne chemical cues in mediating kinship-dependent development.

Main Methods:

• Tadpoles of Spea bombifrons and Spea multiplicata were reared in controlled groups with varying degrees of relatedness (pure vs. mixed sibships).
• The expression of the carnivore phenotype was quantified in each group.
• Food availability, size, and growth rates were controlled or measured to isolate the effect of kinship.

Main Results:

• Spea multiplicata tadpoles were more likely to develop the carnivore phenotype in mixed sibship groups compared to pure sibship groups.
• Spea bombifrons tadpoles were more likely to develop the carnivore phenotype when reared alone versus in pure sibship groups.
• These effects were independent of food availability or individual growth, and non-kin chemical cues triggered carnivore phenotype expression.

Conclusions:

• Kinship environment significantly influences the development of alternative phenotypes, such as the cannibalistic carnivore form in spadefoot toads.
• Waterborne chemical cues signaling relatedness play a role in mediating these developmental responses.
• Morphogenesis is sensitive to kinship, particularly in species exhibiting environmentally induced polyphenism.