The parasitoid Closterocerus chamaeleon has a greater development and survival rate than of its hosts, the Eucalyptus gall wasps Ophelimus eucalypti and Ophelimus maskelli in Sumatra, Indonesia

Abstract

Ophelimus eucalypti and Ophelimus maskelli are gall wasps that are considered as a threat to the large Eucalyptus commercial plantations in Sumatra, Indonesia. However, they are partially suppressed by parasitoids including Closterocerus chamaeleon.The aim of this study was to evaluate the longevity and daily survival rate of O. eucalypti, O. maskelli and C. chamaeleon adults when receiving or not receiving food sources and also when reared in four different vial types under two environments (one environmentally controlled and another ambient), in a laboratory in Riau, Sumatra. The rearing test of C. chamaeleon as a biocontrol agent would be used for augmentative releases. We also evaluated the duration of the stages and the complete lifespan (egg ! larva ! pupa ! adult) of O. eucalypti in a greenhouse in Porsea, North Sumatra, Indonesia, where this species is aggressive. With few exceptions, the longevity and survival rate of O. eucalypti, O. maskelli and C. chamaeleon adults was similar between the two conditions. The longevity and survival of C. chamaeleon were much greater than those of its gall wasp hosts, and of O. eucalypti greater than that of O. maskelli. Overall, these parameters were greater for gall wasps and the parasitoid reared in the larger vial types. The food source provided to O. maskelli adults did not however benefit the longevity of this gall wasp in the best tube type. The lifespan of O. eucalypti (mean ± SD of the mean) was 44 ± 6 days in a greenhouse.The much greater longevity and survival rate of C. chamaeleon than those of its hosts are facts that trigger the success of this insect as a gall wasp parasitoid. The higher longevity and survival of O. eucalypti compared to O. maskelli contribute to the higher threat status of O. eucalypti to Eucalyptus.

Parasitoids associated to Ophelimus eucalypti (gahan) (Hymenoptera: Eulophidae) on Eucalyptus (Myrtaceae) plantations in North Sumatra, Indonesia

“…The C. chamaeleon, originally from Australia, has shown its effectiveness as the most potent natural enemy for O. maskelli [5,10,14]. This parasitoid has a higher survival rate and lifetime than the gall wasps that serve as its host, which may contribute to its success as a biological agent [15]. However, five types out of 6 nine parasitoid species were discovered in Eucalyptus plantations in North Sumatra and are known to be different from those previously reported.…”

A newly invaded eucalypt gall wasp and its parasitoid in China: identification and biology

“…It is expected that compared to the blister-shaped galls on leaves, neoplastic-shaped galls of a high density on petioles may cause more serious damage on the Eucalyptus trees especially the seedlings.Parasitism of C. chamaeleon on O. maskelliClosterocerus chamaeleon was the only parasitoid of O. maskelli found during the study. C. chamaeleon is an ectoparasite with a narrow range of host species among eulophids forming galls on eucalypts(Protasov et al, 2007a), and regarded as the greater potential agent for biological control of O. maskelli due to its thelytokous nature (Doğanla &Protasov et al, 2007b), longer longevity and higher survival rate than its hosts(Sinulingga et al, 2021), and high parasitism rate(Caleca et al, 2011). Here, we show that the parasitism rate of C. chamaeleon increased from 23.4% in February to 97.4% in March 2023 when the population of O. maskelli galls was low (236.8-251.4 galls/20 branches), suggesting that C. chamaeleon may e ciently suppress the population of overwintering O. maskelli in early spring.…”