Spawning Behaviors in the Bluehead Chub, Nocomis leptocephalus, River Chub, N. micropogon and Central Stoneroller, Campostoma anomalum

Abstract

Spawning behaviors were filmed and observed in the nest-building minnows, the bluehead chub, Nocomis leptocephalus, and river chub, N. micropogon. Analysis of videotapes exposed previously unreported behaviors (e.g., female retroflexure) and a precise sequence of male-female interactions that coordinated a successful spawn. Reproductive behaviors were classified into six sequential categories (interim, approach, alignment, run, clasp, dissociation) to facilitate interspecific comparisons. The most conspicuous differences between species involved the intensity of the female's retroflexure and the male's spawning clasp (strong in N. leptocephalus vs. weak in N. micropogon) and reproductive behaviors of subordinate males. In N. leptocephalus, subordinate males spawned concurrently and independently of the resident male over a communal nest, whereas in N. micropogon a subordinate acted like a satellite male and stole spawns from the nest-building male. In addition, heterogeneric spawning clasps involving a male and female N. leptocephalus and a male central stoneroller, Campostoma anomalum, are newly described.