Tamarixia triozae, an important parasitoid of Bactericera cockerelli: circadian rhythms and their implications in pest management

Tian

et al. 2021

Insects

Pyemotes spp. are small, toxic, ectoparasitic mites that suppress Coleoptera, Hemiptera, and Lepidoptera plant pests. To explore their potential use as a biocontrol agent, we studied the reproductive development, paralytic process, time to lethality and mortality, and searching ability of Pyemotes zhonghuajia on different developmental stages of the oriental leafworm moth, Spodoptera litura. Pyemotes zhonghuajia gained 14,826 times its body weight during pregnancy. One single P. zhonghuajia female could rapidly kill one S. litura egg and first to third instar larvae, but not fourth to sixth instar larvae, prepupae, or pupae within 720 min. Pyemotes zhonghuajia could develop on eggs, first to sixth larvae, and pupae, but only produced offspring on the eggs and pupae. A single P. zhonghuajia female (an average weight of 23.81 ng) could paralyze and kill one S. litura third instar larvae (an average weight of 16.29 mg)—680,000 times its own weight. Mites significantly affected the hatch rate of S. litura eggs, which reduced with increasing mite densities on S. litura eggs. Releasing 50 or 100 P. zhonghuajia in a 2 cm searching range resulted in significantly higher mortality rates of S. litura first instar larvae within 48 h compared to second and third instar larvae in searching ranges of 4.5 and 7.5 cm within 24 h. To the best of our knowledge, this is the first study to reveal that P. zhonghuajia undergoes the greatest changes in weight during pregnancy of any adult female animal and has the highest lethal weight ratio of any biocontrol agent.

Section: Methodsmentioning

confidence: 99%

The Biocontrol Agent Pyemotes zhonghuajia Has the Highest Lethal Weight Ratio Compared with Its Prey and the Most Dramatic Body Weight Change during Pregnancy

Tian

et al. 2021

Insects

“…Each vial was provided with a diet saturated in a cotton ball (0.5 cm in diameter) and plugged with cotton wool. Because one-day-old wasps can successfully copulate within one hour after encountering a mate (Chen et al 2020), we kept wasps in their vials for 24 h, and then individually paired males and females that fed on the same diet in glass vials and allowed 2 h for mating to occur. We obtained 28, 30, and 28 mated pairs that fed on honey, yeast, and water diets, respectively, for the second phase of treatments.…”

Section: Treatmentsmentioning

confidence: 99%

Diets for Tamarixia triozae adults before releasing in augmentative biological control

Zhou

et al. 2022

BioControl

Self Cite

The effectiveness of augmentative biological control using parasitoids often depends on their physiological state and the pest population density at the time of release. Tamarixia triozae (Burks) (Hymenoptera: Eulophidae) is a primary host-feeding parasitoid of a serious invasive pest Bactericera cockerelli (Šulc) (Hemiptera: Triozidae). Here we investigated the effects of adult diets (honey, water, yeast, and hosts) and timing of their provision on T. triozae fitness and oviposition patterns, providing knowledge for enhancement of its biological control potential. Adults fed with honey for four days with no access to hosts or with water or yeast for one day followed by host feeding for three days had similar longevity and lifetime pest killing ability. Adults fed with only water for one day before release had significantly greater intrinsic rate of increase, shorter doubling time, and higher daily fecundity peak. Adults fed with honey or yeast for one day followed by host feeding for three days significantly flattened their daily oviposition curves. These findings have several implications for augmentative biological control using T. triozae. First, honey diet may allow at least four days for successful shipment of host-deprived adults without compromising biological control effectiveness. Second, the release of host-deprived adults with one-day water feeding may achieve rapid pest suppression when the pest population density is high. Finally, releasing host-deprived adults with one-day honey or yeast feeding followed by three-day host feeding can increase their establishment success and reduce the risk of massive removal of hosts when the pest population density is low.

“…Design of an effective post‐release monitoring program requires knowing when flight activity of the parasitoid is likely to occur and, during this period, what environmental factors such as temperature, humidity and wind speed will influence adult wasp flight (Rousse et al 2009). Although insects are known to have circadian patterns of activity, almost exclusively this research has been laboratory based with ecological implications extrapolated from such studies (Bertossa et al 2013; Chen et al 2020; Sanders & Lucuik 1975). Determining the interactions of abiotic factors with flight activity directly in the field is more pertinent than the laboratory as a method to increase the success of rearing conditions, field release methods and subsequent field monitoring programs (Coelho et al 2016).…”

Section: Introductionmentioning

confidence: 99%

“…Whipple et al (2013), for example, found significant differences in sweep net catches of grasshoppers during different times of the day and by doing so demonstrated the need for standardised sampling times for rangeland grasshopper management. Furthermore, knowing the flight activity of parasitoids has important implications for integrating biological control with other pest management methods, thereby increasing the potential for success (Chen et al 2020).…”

Section: Introductionmentioning

confidence: 99%

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

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.