Sex allocation and field population sex ratio of Apanteles taragamae Viereck (Hymenoptera: Braconidae), a larval parasitoid of the cucumber moth Diaphania indica Saunders (Lepidoptera: Crambidae)

Sex ratio is one of the most important biological characteristics of arthropods. In a parasitoid population, sex ratio can influence the suppression of host populations or the stability of host–parasitoid interactions in the field. In this study, a survey was carried out to determine the sex allocation through the sequence of male/female adult emergence and calculate the sex ratio of selected populations of Apanteles taragamae in their natural habitat. Assessment of sex ratio at the population and individual level (brood size per female) was examined. We found no difference in the likelihood that either sex would emerge before the other. Observations of sex ratio at the population and individual level reveal a females biased sex ratio. Analysis of the relationship between brood size and sex ratio of A. taragamae shows that brood size may influence the proportion of male to female offspring yielded. A male-biased sex ratio tends to be found in smaller brood size. However, sex ratio is shifted to female biased in larger brood size.

Biology and Reproductive Behaviour of Apanteles taragamae Viereck (Hymenoptera: Braconidae), a Larval Parasitoid of Diaphania indica Saunders (Lepidoptera: Crambidae)

Apanteles taragamae (Hymenoptera: Braconidae) is a larval parasitoid of Diaphania indica (Saunders) (Lepidoptera: Crambidae), a minor pest of Cucurbitaceae crop. The aim of this study was to determine the behavior and biology of A. taragamae. The study was conducted under laboratory conditions by exposing 930 larvae of D. indica to be parasitized by 11 adult female parasitoid of A. taragamae (1 day old), which have been mated 24 hours prior to expose. Each female was exposed to 15 larvae/day until they died. The parameters used to measure the biology of A. taragamae were fecundity, longevity, and parasitism. Results showed that the longevity of adult females was 5.64 days, the parasitism was 96%, the number of egg laid was 76.40/day, the total number of eggs laid was 611.18, and potential fecundity was 752.73 egg.

Pengaruh Ketiadaan Inang terhadap Biologi Reproduksi dan Perilaku Parasitoid Apanteles taragamae Viereck (Hymenoptera: Braconidae)

Apanteles taragamae Viereck (Hymenoptera: Braconidae) is a gregarious larval endoparasitoid of cucumber moth Diaphania indica Saunders (Lepidoptera: Crambidae). The success of biological control using parasitoids depends on reproductive behavior of adult female parasitoids, especially those related to the host availability that can affect oviposition behavior. The objectives of this research is to study the effect of host deprivation against reproductive capacity and searching and handling time behavior of A. taragamae. The study was conducted by depriving adult females of A. taragamae of host for 1, 2, 3, 4 days after emergence (virgin females with no oviposition experience) and experienced females. The parameters observed were the number of eggs laid and parasitization on the first day after treatment, actual fecundity, ovary egg load, potential fecundity, longevity, searching and handling time of the first host after treatment,. The results showed that host deprivation affect the number of eggs laid on the first day after treatment, ovary egg load , searching and handling time of host. Adult virgin females of A. taragamae without oviposition experience has more eggs laid on the first day after treatment, but has a slower searching and handling time for the first host after treatment than females with oviposition experience.IntisariApanteles taragamae Viereck (Hymenoptera: Braconidae) merupakan parasitoid larva utama dari Diaphania indica Saunders (Lepidoptera: Crambidae) yang bersifat gregarius. Keberhasilan pengendalian hayati menggunakan parasitoid sangat tergantung pada perilaku reproduksi imago betina parasitoid, terutama yang berhubungan dengan ketersediaan inang yang dapat memengaruhi perilaku peletakkan telur. Penelitian ini bertujuan untuk mempelajari pengaruh ketiadaan inang terhadap perilaku dan kapasitas reproduksi parasitoid A. taragamae. Penelitian dilakukan dengan cara memberikan perlakuan berupa ketiadaan inang selama 1, 2, 3, dan 4 hari setelah kemunculan A. taragamae menjadi imago (ketiadaan inang di depan) dan setelah A. taragamae mendapatkan inang terlebih dahulu (ketiadaan inang di belakang). Parameter yang diamati adalah jumlah telur yang diletakkan pada hari pertama setelah perlakuan, total telur yang diletakkan, sisa telur dalam ovari, potensi produksi telur, lama hidup imago A. taragamae, serta waktu pencarian dan penanganan inang pertama setelah ketiadaan inang. Hasil penelitian menunjukkan bahwa perlakuan ketiadaan inang memberikan pengaruh terhadap jumlah telur yang diletakkan pada hari pertama setelah perlakuan, jumlah telur yang tersisa dalam ovari, serta waktu pencarian dan penanganan inang pertama setelah perlakuan. Imago A. taragamae pada perlakuan ketiadaan inang di depan meletakkan telur yang lebih banyak pada hari pertama setelah perlakuan, namun memerlukan waktu lebih lama dalam mencari dan menangani inang pertama dibandingkan imago A. taragamae pada perlakuan ketiadaan inang di belakang.