Life history of Nephaspis oculatus (Coleoptera: Coccinellidae), a predator of Bemisia argentifolii (Homoptera: Aleyrodidae)

Abstract

Nephaspis oculatus (Blatchley) is a common introduced coccinellid predator in Florida, which feeds on many whitefly species. We evaluated development, consumption rates, survivorship, longevity, and fecundity of a southern Florida (Immokalee) population of this coccinellid on a diet of eggs of Bemisia argentifolii Bellows and Perring. Developmental time was 4.6, 3.3, 1.5, 1.5, 3.0, and 5.2 d for eggs, 1st, 2nd, 3rd, 4th instars, and pupae, respectively, with an average of 19.4 d from oviposition to adult emergence for females and 18.3 d for males. Daily consumption of whitefly eggs by male and female larvae was not significantly different (average 79 for males, and 86 for females) with a mean of 16, 128, and 124 eggs consumed per larva per day by 1st, 2nd, 3rd, and 4th instars, respectively, totaling 51, 132, 192, and 373 eggs for each successive larval stage. Male-female pairs of adults consumed a mean of 184.1 eggs per day over a period of 16 wk. Adult females from a 2nd population in central Florida (Apopka) consumed an average of 78.0 B. argentifolii eggs per day over a period of 5 wk, and males consumed 123.0 eggs per day. The sex ratio of l153 beetles was 1.00:0.89 female to male. Adult longevities averaged 56.1 d for males, and 67.5 d for females. After an average 11.3-d preoviposition period, females laid a mean of 3.03 eggs per day. Net reproductive rate was estimated by life table analysis at 54.27, generation time was 51.27 d, and doubling time was 8.89 d. Intrinsic rate of population increase was estimated at 0.078, or λ=1.08 for finite rate of increase. N. oculatus showed good potential for biological control of B. argentifolii, especially in greenhouses.