Multiple regression of TE-derived piRNA abundance. (A) Extra SS F-statistics and (B) effect estimates are reported for each variable in the best-fit multiple regression model of antisense (solid bars) and sense (light bars) piRNA abundace. Ping-pong fraction × maternal deposition denotes an interaction between these terms. Bar coloring is as in figure 1. *P < 0.05; **P < 0.01; ***P < 0.001.