Larval Odon. were identified from quantitative samples of water lettuce made from a single
pond. 3 spp. of Zygoptera accounted for more individuals but less biomass than 4 spp. of
Anisoptera. Numbers of larvae were highest in the winter when smallest size classes
predominated, and lowest in the spring and summer when larger size classes were present.
Size class data indicated a probable spring emergence for Telebasis byersi and
Pachydiplax longipennis and an autumnal emergence for Coryphaeschna adnexa. Foregut …

The cosmotropical macrophyte Pistia stratiotes L. is known to be an important nursery for
aquatic insect life (DUNN, 1934; MACFIE & INGRAM, 1923). Among insect orders found on
P. stratiotes in Volta Lake, Ghana, larval Odonata dominatedin biomass and were second to
Diptera in absolute numbers (PETR, 1968). Representatives of at least five genera of
Anisoptera and three genera of Zygoptera were recovered during Petr's ten-month study.
Larval Anisoptera accounted for approximately ten times more biomass thanZygoptera on …