Host testing of Eadya daenerys, a potential biological control agent for the invasive chrysomelid pest Paropsis charybdis, predicts host specificity to eucalypt-leaf feeding Paropsina

Withers, T. M.; Todoroski, CL; Allen, Gordon; Pugh, Andrew R.; Gresham, BA

doi:10.1007/s10526-019-09978-6

Cited by 5 publications

(17 citation statements)

References 23 publications

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“…No female parasitoid was tested more than once against any one non‐target species in the same assay type but may have repeatedly been used on a different day against another non‐target, and to oviposit into P. charybdis larvae for colony rearing (Withers et al, 2020).…”

Section: Methodsmentioning

confidence: 99%

“…Four species from the same sub-family as the target (Chrysomelinae: D. semipunctata, C. abchasica, G. olivacea, and A. nr. tarsalis; Table S1) revealed some internal parasitism by E. daenerys in physiological assays (Withers et al, 2020) even though those species did not support complete development of the parasitoid. The results of rearing non-target larvae attacked in these assays supported this evidence, i.e., incomplete internal parasitism in C. abchasica and A. nr.…”

Section: Risk Assessment Conclusionmentioning

confidence: 99%

“…To assess the non-target species that may be at risk from an introduced parasitoid we examined the Chrysomelidae sub-family relationships from Reid (1995) and Leschen & Reid (2004). This resulted in close consideration of all NZ species of Galerucinae, the sister sub-family to the Chrysomelinae, as well as NZ native and beneficial introduced Chrysomelidae (Withers et al, 2015(Withers et al, , 2020. Two methods of assessing non-target risk were compared to ensure we had included the most appropriate species on the host testing list (Withers et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

“…The behavioural observations during choice and no-choice tests were undertaken within Scion's insect containment facility in Rotorua, NZ. Physiological host development assays were also conducted (Withers et al, 2020), with both research studies completed prior to NZ government approval for E. daenerys field release being granted in 2019.…”

Section: Introductionmentioning

confidence: 99%

“…In terms of testing galerucines, we chose to test exotic rather than endemic species, one from each of the two tribes Galerucini and Alticini. This was a practical choice as galerucines are characterised by soil‐dwelling root feeders whereas alticine ‘flea beetles’ are usually miniscule but biologically diverse (Withers et al, 2020). The two weed biocontrol agents were larger than any NZ species, spring‐time active, leaf feeders, and easily obtainable.…”

Section: Introductionmentioning

confidence: 99%

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Observations of parasitoid behaviour in both no‐choice and choice tests are consistent with proposed ecological host range

Withers

Allen

Todoroki

et al. 2020

Entomologia Exp Applicata

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The solitary larval endoparasitoid Eadya daenerys Ridenbaugh (Hymenoptera: Braconidae) is a proposed biocontrol agent of Paropsis charybdis St al (Coleoptera: Chrysomelidae, Chrysomelinae), a pest of eucalypts in New Zealand. Eadya daenerys oviposition behaviour was examined in two assay types during host range testing, with the aim of improving ecological host range prediction. No-choice sequential and two-choice behavioural observations were undertaken against nine closely related species of New Zealand non-target beetle larvae, including a native beetle, introduced weed biocontrol agents, and invasive paropsine beetles. No behavioural measure was significantly different between nochoice and two-choice tests. In sequential no-choice assays the order of first presentation (target-nontarget) had no significant effect on the median number of attacks or the attack rate while on the plant. Beetle species was the most important factor. Parasitoids expressed significantly lower on-plant attack rates against non-targets compared to target P. charybdis larvae. The median number of attacks was always higher towards target larvae than towards non-target larvae, except for the phylogenetically closest related non-target Trachymela sloanei (Blackburn) (Coleoptera: Chrysomelidae, Chrysomelinae). Most non-target larvae were disregarded upon contact, which suggests that the infrequent attack behaviour observed by two individual E. daenerys against Allocharis nr. tarsalis larvae in two-choice tests and the frass of Chrysolina abchasica (Weise) was probably abnormal host selection behaviour. Results indicate that E. daenerys is unlikely to attack non-target species apart from Eucalyptus-feeding invasive paropsines (Chrysomelinae). Non-lethal negative impacts upon less preferred non-target larvae are possible if E. daenerys does attack them in the field; however, this is likely to be rare.

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Section: Methodsmentioning

confidence: 99%

Section: Risk Assessment Conclusionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Observations of parasitoid behaviour in both no‐choice and choice tests are consistent with proposed ecological host range

Withers

Allen

Todoroki

et al. 2020

Entomologia Exp Applicata

View full text Add to dashboard Cite

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Why introducing a parasitoid of Paropsis charybdis Stål, 1860 (Coleoptera: Chrysomelidae) larvae is expected to enhance biological control of this Eucalyptus pest in New Zealand

et al. 2020

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Paropsis charybdis (Coleoptera: Chrysomelidae) has been a major pest of Eucalyptus spp. since invading New Zealand from Australia over 100 years ago. Here, we report on the phenology, egg parasitism and defoliation levels of P. charybdis at two Eucalyptus nitens plantations in the central North Island of New Zealand and assess the establishment prospects and potential impact of a new biological control agent, the larval parasitoid Eadya daenerys. Field monitoring found that 90–100% of first generation P. charybdis eggs emerged, showing that the existing egg parasitoids Enoggera nassaui (Hymenoptera: Braconidae) and Neopolycystus insectifurax (Hymenoptera: Pteromalidae) are ineffective at controlling this generation. Further field monitoring revealed effective control of second generation eggs by E. nassaui and N. insectifurax despite the presence of Baeoanusia albifunicle (Hymenoptera: Encyrtidae), a hyperparasitoid of E. nassaui. Phenology data show that first generation P. charybdis larvae will likely be synchronous with the adult emergence of E. daenerys (Hymenoptera: Braconidae) the new larval endoparasitoid proposed to be introduced from Australia. Climate matching predicts E. daenerys could establish in all areas of New Zealand where P. charybdisimpacted Eucalyptus spp. plantations are grown. The addition of a larval endoparasitoid could significantly contribute to the suppression of P. charybdis by decreasing first generation larval survival.

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Circadian and seasonal flight activity differences between the sexes of the biocontrol agent Eadya daenerys (Hymenoptera: Braconidae) and the impact of host size on adult emergence

et al. 2023

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Since its accidental introduction into New Zealand in 1916, the invasive eucalypt leaf beetle Paropsis charybdis remains a pest of economic significance to Eucalyptus forestry. For this reason, the braconid parasitoid Eadya daenerys has been approved for release as a classical biological control agent. To aid in field monitoring using hand netting of biocontrol releases and laboratory rearing protocols, the flight activity over 6 a year field research program of E. daenerys and the relationships between the parasitoid and the size of its beetle hosts were evaluated in the country of origin. Wasps were observed flying over 32 days from mid‐November to mid‐December in Tasmania. E. daenerys was found to exhibit a morning‐based scramble competition mating system. Females flying in the early morning had lower mature egg loads (134.2 ± 27.6) than at other times of the day. In the first half of the season, male flight was most often seen in the early morning, whereas in the second half of the season, there was a 4.5‐fold decrease in any wasps flying. Female flight activity significantly increased to 70% female in the evening hours from 5:00 pm to 8:00 pm, which by the second half of the season was almost exclusively female. Wasps were caught flying across a wide range of air temperatures (10.7–23.8°C), humidity and light levels, but even light winds reduced flight when average wind speed exceeded 0.27 m/s for males and 0.73 m/s for females. Beetle prepupal weight was a predictor of E. daenerys parasitism success with mean beetle prepupal weights significantly higher for stung but unsuccessfully parasitised larva (62.09 mg) than those successfully parasitised (52.94 mg). The chance of an emerged wasp larva spinning a pupal cocoon was found to increase by 5% with every 1‐mg increase in its beetle prepupal weight. Heavier beetle prepupae produced bigger parasitoids. Field‐collected adult E. daenerys had larger (12%) head capsule widths (mean of 1.42 mm) than those reared in the laboratory (mean of 1.27 mm), suggesting that improving host nutrition and laboratory rearing conditions for increasing host size may help optimise E. daenerys rearing success.

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Host testing of Eadya daenerys, a potential biological control agent for the invasive chrysomelid pest Paropsis charybdis, predicts host specificity to eucalypt-leaf feeding Paropsina

Cited by 5 publications

References 23 publications

Observations of parasitoid behaviour in both no‐choice and choice tests are consistent with proposed ecological host range

Observations of parasitoid behaviour in both no‐choice and choice tests are consistent with proposed ecological host range

Why introducing a parasitoid of Paropsis charybdis Stål, 1860 (Coleoptera: Chrysomelidae) larvae is expected to enhance biological control of this Eucalyptus pest in New Zealand

Circadian and seasonal flight activity differences between the sexes of the biocontrol agent Eadya daenerys (Hymenoptera: Braconidae) and the impact of host size on adult emergence

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