Some biological parameters of Sympiesis striatipes (Hym.: Eulophidae), an ectoparasitoid of the citrus leafminer Phyllocnistis citrella (Lep.: Gracillariidae)

The biological parameters of Sympiesis striatipes Ashmead, one of the most abundant hymenopterous ectoparasitoid of Phyllocnistis citrella Stainton in Ehime province of Japan, were studied under laboratory and field conditions. The mean immature developmental time and adult longevity at different temperatures (22 to 31°C), 50-70% RH and 12L: 12D photoperiod decreased as the temperature increased, and females survived longer than males. Offspring sex ratio from females provided with males was 84.7% males and 15.3% females. Presumably mated females began oviposition 2-3 days after emergence and continued up to 39 days. Each female laid a mean of 123.4 ± 13.97, and longevity reached 33.8 ± 1.5 days at 27 ± 1°C, 50-70% RH and 12L: 12D photoperiod. The intrinsic rate of natural increase (rm) was 0.312. Host feeding or stinging without oviposition killed 44.7 ± 4.2 host larvae per female parasitoid. Seventy five point eight percent of eggs were laid on third instar larva of host and the remainder on the prepupa. Under field conditions, superparasitism on the third instar larvae was 9.2% (n = 200) and up to 7 eggs per host were recorded. Under superparasitism lethal competition (n = 40), one adult parasitoid per host emerged from 87.5% of the samples and two adult parasitoids per host emerged from the rest. Superparasitism on prepupa was rare. The sex ratio (M: F) of the parasitoid oviposited on the third instar larvae of host and pupae was 2.2: 1.0, and 1.3: 3.0, respectively.