NEOSEIULUS-CALFORNICUS (MCGREGOR) AND NEOSEIULUS-FALLACIS (GARMAN) - LARVAL RESPONSES TO PREY AND HUMIDITY, NYMPHAL FEEDING DRIVE AND NYMPHAL PREDATION ON PHYTOSEIID EGGS

Are Neoseiulus californicus (McGregor) and Neoseiulus fallacis (Garman ) both specialized predators of spider mites? As part of a series of s tudies made to answer this question, responses by larvae were assessed in treatments either with or without prey (Tetranychus urticae Koch) and with either moderate or high relative humidities (st factor that m ay distinguish between these two morphologically similar species). Neo seiulus fallacis larvae had more feeding, ambulatory activity and jerk ing (intra- or interspecific communication) in all treatments than N. californicus. The percent egg hatch was less and development took long er for N. fallacis larvae than for N. californicus larvae without prey at moderate humidity levels. The nymphs of both mites showed similar drives to feed 1-2h after being held 12-48 h without food and then giv en eggs of T. urticae. Neoseiulus californicus nymphs fed more on the eggs of either phytoseiid and thereafter became adults than did N. fal lacis nymphs. These data indicate that N. californicus may be a less s pecialized predator of spider mites than is N. fallacis.