Juvenile anoles seem to utilize very different habitats than adults of the same species. Could this be a product of intraspecific competition between age classes?
David Delaney, a master’s student in Dan Warner’s lab at the University of Alabama, Birmingham, set out to answer this question using brown anoles (Anolis sagrei), and presented a poster describing his experimental study at SICB this week. He manipulated the densities of adult lizards cohabiting with 6 juvenile lizards within mesh enclosures containing artificial trees in five treatment groups. These groups were: (1) no adults; (2) 1 adult male; (3) 1 adult female; (4) 3 adult males; (5) 3 adult females. Unexpectedly, adult density did not affect the microhabitat use (perch height, perch width, or substrate composition) of juvenile lizards in the enclosures. However, when three adult male lizards were present, juvenile survival rate decreased and larger juveniles were more likely to survive. These results are intriguing because adult males are a selective force on juveniles, yet in this study, juveniles did not alter their microhabitat use in response to adults. The next question, then, is what is causing the distinct habitat use differences between adults and juveniles in the wild?
Note: This post was written by Bonnie Kircher, a graduate student studying anole development in Marty Cohn’s lab at the University of Florida.