Predation efficiency and capacity of the. larvae of three libellulid dragonflies (Anisoptera: Libetluidae)

HASSAN, A.T.

The predation efficiency of the final and penultimate instar larvae of Urothemis assignata Selys, Palpoleura lucia (Drury) and Acisoma panorpoides Selys on six prey
types was studied in the laboratory. Predation efficiency on tadpoles, zygopteran larvae ephemeropteran larvae and ostracods was high (40 to 92%); it was highest on ephemeropteran larvae (76 to 92%) and lowest on zygopteranlarvae (40 to 720/0). Predation efficiency was also low on fish fry (0 to 56%) and anisopteran larvae (24 to 50%). The prey type, the size of prey, the movement pattern of prey, the size of the libellulid larvae and their agility influenced predation efficiency. Predation capacity was high; prey were still killed even after the larvae were satiated. It seems that a regulation of food intake exists in the larvae of the three Iibellulid larvae.

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